Causality and Causal Explanation in Aristotle 2022062180, 2022062181, 9780197660867, 9780197660881, 019766086X

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Causality and Causal Explanation in Aristotle

Causality and Causal Explanation in Aristotle NAT HA NA E L ST E I N

Oxford University Press is a department of the University of Oxford. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide. Oxford is a registered trade mark of Oxford University Press in the UK and certain other countries. Published in the United States of America by Oxford University Press 198 Madison Avenue, New York, NY 10016, United States of America. © Oxford University Press 2023 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, by license, or under terms agreed with the appropriate reproduction rights organization. Inquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above. You must not circulate this work in any other form and you must impose this same condition on any acquirer. Library of Congress Cataloging-in-Publication Data Names: Stein, Nathanael, 1976– author. Title: Causality and causal explanation in Aristotle / Nathanael Stein. Description: New York, NY : Oxford University Press, [2023] | Includes bibliographical references. Identifiers: LCCN 2022062180 (print) | LCCN 2022062181 (ebook) | ISBN 9780197660867 (hardback) | ISBN 9780197660881 (epub) | ISBN 9780197660898 Subjects: LCSH: Aristotle. | Causation. | Explanation. Classification: LCC B 49 1 .C 3 S 84 2023 (print) | LCC B 4 9 1 . C 3 (ebook) | DDC 122—dc23/eng/20230314 LC record available at https://lccn.loc.gov/2022062180 LC ebook record available at https://lccn.loc.gov/2022062181 DOI: 10.1093/​oso/​9780197660867.001.0001 Printed by Integrated Books International, United States of America

Contents Preface  Abbreviations and Editions Cited of Aristotle’s Works 

Introduction 

I.1. The Basic Problem  I.2. Outline  I.3. Themes, Consequences, Comparisons, and Absences 

ix xiii

1

1 12 18

PA RT I :   C O N C E P T UA L ST RU C T U R E 1. Reading (and Animating) Physics II 3 

25

2. Background 1: Critiques of the Predecessors 

37

3. Background 2: Science and Dialectic 

55

4. Physics II 3 in Argumentative Context 

71



1.1. The Problem of Physics II 3  1.2. Physics II 3 in the Context of Book II  2.1. Epistemological and Scientific Critiques  2.2. Metaphysical Critiques  2.3. Summary 

3.1. Being “in Virtue of Oneself ” and in Other Ways  3.2. Physics II 2 and the Autonomy of Natural Science  3.3. Posterior Analytics II 11 and the Simple Schema of Causes  3.4. Summary  4.1. Highlights  4.2. Implications for Theory and Method  4.3. Causal Pluralism  4.4. Strengths, Weaknesses, and Open Questions 

25 29 37 44 53 55 60 62 69 71 79 82 87

PA RT I I :   M E TA P H YSIC S 5. The Realist Challenge 

5.1. Metaphysical Pluralism  5.2. Clarifying the Question 

95

95 100

vi Contents

6. Causes, Kinds, and Transformations 

105

7. Causal Kinds and Causal Profiles 

131

8. Discreteness in Agent–​Patient Relations 

162



6.1. From Privileged Entities to Intrinsic Causes  6.2. Essentialism and Kinds of Natural Change  6.3. Pre-​theoretical and Theoretical Accounts of Change  6.4. Real Definitions of Transeunt Interactions  6.5. Summary  7.1. Real Definitions and Causal Profiles  7.2. The Varieties of Causal Profile  7.3. Connections and Correspondences to Other Distinctions  7.4. Causal Profiles at Work: Gluttonous Birds  7.5. Implications for Puzzles about Aristotelian Causality  7.6. Summary  8.1. The Realist Question  8.2. “Ways of Being Causes” in Physics II 3  8.3. Transeunt-​Causal Change in Physics III 3  8.4. Varieties of Discreteness  8.5. Discreteness Applied  8.6. Aristotle and Modern “Neo-​mechanism”  8.7. Summary, Comparisons, and Open Questions 

105 112 116 123 129 131 133 145 148 152 160 162 165 174 181 186 190 193

PA RT I I I :   E P I ST E M O L O G Y 9. Coming to Know Causes 

199

10. Causality and Epistemic Asymmetries 

217



9.1. Basic Questions about Grasping Causes  9.2. Causes and the Two Images  9.3. A Problem of Induction  9.4. Stages of Inquiry and Their Associated States or Capacities 

10.1. Manifest Causes and Basic Asymmetries  10.2. The Priority of Transeunt-​Causal Efficient Causality  10.3. Grasping Transeunt-​Causal Interactions  10.4. Understanding Origin-​Dominant Causal Profiles  10.5. Summary 

199 201 205 212 217 223 225 233 235

Contents  vii

11. The Non-​Secret Connexion 

237

Conclusion 

255

Bibliography  Index Locorum  Subject Index 

261 273 281



11.1. Is Some Causality Just as It Appears?  11.2. The Special Importance and Epistemic Status of Crafts  11.3. The Nature of Blood  11.4. Summary: Causal Explanation and Aristotle’s Empiricism 

237 240 244 251

Preface Philosophical problems get some of their extra bite from the fact that they are two-​faced: we are typically unsure what to say about the subject matter itself but also puzzled about the right way to approach it. Questions about causality and explanation have persistently been a focus of those two sorts of puzzlement for me—​not knowing what to say about them, and not knowing how to start looking for answers. Now, Aristotle connects causality directly to the natural human desire to know, and I think it is, above all, that connection that is the source of its abiding interest: not just in relation to scientific explanation or metaphysics, but in relation to almost any domain in which we have an impulse to understand and therefore to explain—​and to feel like we have the explanation, even at the cost of self-​deception. That impulse drives a whole range of behavior, from scientific and philosophical inquiry, to historical explanation, all the way down to arguments about the meaning of election results, clickbait, and conspiracy theories. By nature, we desire to know, especially if there’s a chance that reality is different from the appearances. If you’re a suspicious type, or just think it’s generally good policy to be circumspect even around your own ideas, then you may naturally start to wonder about the difference between good and bad explanations. As a philosopher, you may also start to wonder about good and bad approaches to explanation, and one way to get a grip on that problem is to cast a wide net, going back as far as possible. Aristotle is almost as far back as you can go for a self-​conscious discussion of causality and causal explanation, and a great many paths in philosophy and its history lead back to his understanding of causes and their role in explaining the natural world. But here, I think, we find ourselves in a strange position. On the one hand, Aristotle says so much about causes, and his thinking about them permeates so much of his work, that they constitute in a way a main point of entry into his theoretical and natural philosophy. On the other hand, they are so rarely a focus of his direct philosophical attention—​so rarely a focus of argument as opposed to a tool for building an argument, or a framework for guiding an inquiry about something else—​that it isn’t nearly as clear as one might have thought what his theory of causality really is. Thus, in ways that I will make

x Preface more precise in the Introduction, in spite or even because of its centrality to so much of his work, we cannot really answer some basic questions about Aristotle’s views on causality in the way that we can for Plato, Hume, Kant, and others. This gap is not just unfortunate: given the role Aristotelian causality has played in the history of philosophy and science, and the role it is supposed to play in standard accounts of how modern thought and especially modern science have broken with the past, it really shouldn’t be allowed. Furthermore, when we look at contemporary discussions of causation, we find a proliferation of approaches with very little that counts as common ground or even common sense, especially as previously dominant approaches have come to be just one among many. So it would be of interest to get a clear idea of the theory that is in some ways the point of origin for theorizing about causality in Western philosophy and science, even for those aiming to flee it. For these reasons, I want to try to have a philosophical conversation about causality with Aristotle, a conversation of the kind that has proven so fruitful in other domains, but which has in some ways been missing here, however much attention has been devoted to the wide array of particular topics on which he brings his causal notions to bear. In some ways this book goes all the way back to the beginning for me. The route that I have just described, from generalized puzzlement about how one should satisfy one’s desire to know to wanting a better philosophical account of Aristotle’s theory of causality, is in fact a cleaned-​up version of how I went from being a confused and dissatisfied undergraduate to whatever it is that I am now. Along the way I wrote my dissertation on causality and explanation in Aristotle; some of the ideas in it and from subsequent papers survive here in some altered form, but it represents a fresh start, and as far as possible I do not repeat here what I have said in print elsewhere, or cover the same ground. I aim instead to keep the discussion rather tightly focused on questions about the kinds of philosophical challenge for which Aristotle thinks that a correct account of causality is crucial, what he thinks that account is, and how we should assess it, both as a response to those challenges and as a philosophical theory in general. So while parts of this book will mainly interest specialists in ancient philosophy, the argument as a whole is meant for anyone interested in philosophical theories of causation and explanation and their history, as well as anyone who has read Aristotle’s thoughts on the topic of causality and come away wondering what it all really adds up to, and how we might engage with it.

Preface  xi Because this project goes so far back, the list of those to whom I’m indebted is long. Especially important for me are the debts that have less to do with the content of the book than with the people along the anything-​ but-​straight path from the beginnings of graduate school to actual employment who, for whatever reason, saw fit to give me their time, help, or just some much-​needed encouragement on the basis of what must have been, at the start at least, very slight evidence of any promise. These include David Rosenthal, Nick Pappas, Michael Tooley, Bob Pasnau, David Charles, Terry Irwin, Lindsay Judson, Roger Crisp, Ursula Coope, and Jonathan Lear. The biggest debts by far, though, accumulated over many years, are owed to Chris Shields. I wouldn’t know where to start. As to the content of the book, I have received helpful feedback at various stages from a variety of audiences, including those at the Ancient Philosophy Seminar at the University of Oxford, Syracuse University, the University of Coimbra, the University of Campinas, the Center for the Aristotelian Tradition at the University of Notre Dame, and in many different contexts from colleagues at Florida State. I’m grateful for feedback from several readers, including Andrea Falcon, Devin Henry, Thomas Johansen, Michael Strevens, and especially Jessica Gelber and the participants at the workshop she organized at the University of Toronto, as well as Peter Ohlin at OUP. More materially, it is a pleasure to thank the National Endowment for the Humanities, a fellowship from which made it possible for me to give this project my full attention. Finally, I thank my friends and family, especially my mother, Cecile, and my wife, Hashi, for support—​again stretching back to a time of great uncertainty and maybe unfathomable decision-​making on my part. I dedicate the book to my father, Michael, who died right in the middle of the route I have described, whose love and life remain a constant source of good in my own.

Abbreviations and Editions Cited of Aristotle’s Works [APo.] [APr.] [Cat.] [DA] [DC] [De Juv.] [De Motu] [De Somno] [GA] [GC] [HA] [Met.] [Mete.] [EN] [PA] [Phys.] [Pol.] [Top.]

Posterior Analytics (Ross 1949) Prior Analytics (Ross 1949) Categories (OCT) De Anima (OCT) De Caelo (Bekker 1831) On Youth, Old Age, Life and Death, and Respiration (Bekker) Motion of Animals (Nussbaum 1978) On Sleep and Waking (Bekker) Generation of Animals (Peck 1943) De Generatione et Corruptione (Joachim 1922; Rashed 2005) History of Animals (Bekker) Metaphysics (Ross 1924) Meteorology (Bekker, Fobes 1919) Nicomachean Ethics (OCT) Parts of Animals (Bekker, Peck 1937) Physics (Ross 1936) Politics (OCT) Topics (OCT)

Introduction I.1.  The Basic Problem Causality is at the heart of Aristotle’s philosophical project, and at the same time it so permeates his work that it can come to seem indistinguishable from that project as a whole, or whatever part of it one happens to be looking at. It is at the heart of his project because, in his view, it is at the core of understanding in the most ambitious sense: our highest cognitive achievement as rational beings, whether identified as wisdom (sophia) or scientific knowledge (epistêmê), is held to consist in coming to grasp the causes of things.1 At the same time, when he articulates, in Metaphysics I, how his own thought has advanced and improved upon that of his predecessors, he famously does so by casting the history of attempts at a rational understanding of the natural world in terms of the progressive discovery of the four causes (aitiai), the progress being nonetheless so limited that, he says, “in a certain way they have all been described before, while in another way, not at all” (Metaphysics I 10, 993a14–​15). He thus thinks that causality is both at the heart of any theoretical undertaking and that the correct understanding of it is central to his own philosophical achievement. For all that, and for all the influence his claims about causality have had over the centuries, it is surprisingly difficult to say what the theory is, or whether it is even a theory at all. By this I mean that it is unclear, from what Aristotle says and what his commentators have said about it, (a) how he answers the main philosophical questions about causes to which he thinks his predecessors’ answers are flawed, and (b) how his answers bear on the main questions we confront in thinking about causality in general, such that they could be usefully critiqued, defended, developed, and compared with others. 1 ‘Wisdom’ is used in Metaphysics [Met.] I, ‘scientific knowledge’ or ‘understanding’ (sometimes a better translation of epistêmê) is more often the term used elsewhere, as in the Posterior Analytics [APo.]. Regardless of the term, Aristotle consistently identifies grasping causes with a higher grade of cognitive achievement, close to if not identical with our primary aim as potential knowers.

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0001

2  Causality and Causal Explanation in Aristotle Here are some of the questions I have in mind. Granted that Aristotle is some kind of pluralist, in that he recognizes multiple different types or modes of causality, what is the basis of those distinctions, and why should we accept them? Are these causes subject to further distinctions or further unification? What are the criteria by which a certain relationship is to be considered a causal one, rather than, say, a correlation or a merely conditional relationship? What, precisely, are the metaphysical relationships between causes and their effects? How do we, on the basis of experience or observation, come to understand causal relationships, so that we are justified in thinking that certain elements of nature are genuinely responsible for others, rather than simply correlated with one another? These are not just questions we wish to answer in our own, modern discussions of causality. As we shall see, they overlap considerably with the questions Aristotle puts to his predecessors, and they underlie the criticisms he makes of their views. Now, it is easy enough to list “the four causes” by the names traditionally applied to them by later commentators—​the efficient, formal, material, and final causes—​and to analyze some examples of artifacts like statues and houses in terms of them.2 Indeed, a typical account of Aristotle’s theory of causality will do just that, and then show how Aristotle intends those modes of causality to apply to far less obvious relationships, such as the constitution of a natural organism and its relationship to its own body and bodily activities. Such a presentation is fine as far as it goes, but it mainly serves to sharpen the difficulties we face in understanding Aristotle’s views about causality and natural science. A reader may well find the initial examples quite clear, the later ones quite unclear, and then wonder at the end of it what has actually been presented—​a theory? a doctrine? a schema? It has been called all of these, suggesting that commentators themselves are uncertain about it, and indeed there is good reason to be so without a sense of either an argumentative background or some other motivating concern—​and Aristotle does not give one when he presents his distinctions. The standard presentation does not provide answers to questions of the sort I have just raised.3 2 As is often noted, these labels are not Aristotle’s, though he has standard ways of referring to them—​e.g., the efficient cause is often referred to as “the origin of the change” (hê archê tês kinêseôs) or “the principle from which the change originates” (hothen hê archê tês kinêseôs). The labels appear to trace back at least to the second century CE: Ptolemy refers to four “well-​known causes: material, acting, formal, and final” (“tessara eisi polluthrullêta aitia: hulikon poiêtikon eidikon telikon,” Musica, § 26 ln. 2). 3 Certainly, there is no simple way to cast the standard presentation as a theory, though commentators sometimes do this. Aristotle does not claim in these chapters that citing all these four

Introduction  3 It is a much more straightforward matter, by contrast, to reconstruct the core philosophical commitments of Platonic, Humean, or Kantian accounts of causality, and to identify contemporary thinkers whose views constitute, deliberately or not, developments of those positions, than it is for Aristotle’s. There are, of course, many problems and disputes that arise in reconstructing or evaluating their views—​I do not mean to suggest that the content of Kant’s theory of causality, for example, is especially obvious. I mean, rather, that the task of presenting their theories in such a way as to make reconstruction and evaluation possible is easier for these thinkers, in part because they raise and address philosophical questions about causality more directly than Aristotle does. When Plato has Socrates introduce the theory of Forms as causes in the Phaedo, for example, Socrates gives explicit statements about the types of questions he was investigating, why he was dissatisfied with his predecessors’ answers, what he thought a good answer should do, the logical status of his own answer, and how (and to what extent) he thinks that answer solves the problems he raises.4 That is, even if the content of the view needs clarification, the core claims are explicit and the philosophical context is well-​marked. Further, when Plato returns to the general topic of the causal explanation of coming-​to-​be in nature in the Timaeus, he has Timaeus introduce several distinctions among types of causes; here, too, there is a clear

causes is either necessary or sufficient for understanding any natural thing, or for understanding a special kind of natural thing (e.g., substance), nor does he list four causes for any one particular kind of thing, even an artifact. The closest he gets to such a claim in Physics II is in c­ hapter 7, 198b5–​9, where he states that “we render the Why in all ways,” sketching all four types of answer, but this is not itself a claim that all or some particulars have all four types of cause, nor does it present reasons for thinking these four modes are necessary for causal explanations. Rather, it is supposed to follow from the preceding discussion, none of which involves a claim that they are jointly necessary or sufficient for explaining a particular entity or type of entity. In one of the rare passages where he does list four causes for a single entity (a human being), Met. VIII 4, 1044a32–​b1, Aristotle only says that, when seeking something’s cause, since causes are spoken of in many ways, one must state all possible (kinds of) causes. He then immediately gives examples of cases in which there are fewer than four causes to be named. 4 Phaedo, 96a5–​107b10, on which see, for example, Vlastos 1969; Fine 1986; Devereux 1994; Sedley 1998; Silverman 2002, ch. 3; and Dancy 2004, ch. 13. There is, of course, no shortage of treatments of Hume’s arguments in the Treatise and the Enquiry; recent treatments include Kail 2007. For a full-​scale account of Kant’s theory of causality, see Watkins 2004. Modern treatments of a broadly Platonic character include, prominently those of Dretske 1977; Tooley 1977, 1987; and Armstrong 2016, ch. 6, who all account for causation in terms of nomological relationships between universals, despite Armstrong’s scruples about the nature of universals themselves. An explicitly neo-​Kantian approach is framed by Price 2007 (see also the introduction to the volume in which it is included). Neo-​Humean approaches are, of course, widespread, including not only the various types of counterfactual analysis but also more reductive regularity approaches inspired by Mackie 1974.

4  Causality and Causal Explanation in Aristotle attempt to spell out the reasons for introducing these distinctions and what work they are meant to accomplish.5 Philosophical theories are also partially self-​reflective, however: they contain both claims about the topic at hand as well as a view, implicit or explicit, about how we should think or argue about that topic itself. Second-​order questions of this sort include, for example: Why do we need a theory of causality at all? What problems or disputes is a theory of causality meant to resolve? What are the standards we might use to evaluate such a theory, and what types of evidence have the most authority? Here again, at least the broad outlines of this second-​order thinking are more explicit for philosophers like Plato, Hume, and Kant. Plato has Socrates, in the Phaedo, present his dissatisfaction with “materialist” accounts of natural phenomena, especially insofar as their explanations of generation and change display the kind of inadequacy he thinks generally affects perceptible reality—​the kind of instability by which something alleged to be a source of beauty in one context will be a source of ugliness in another, making both claims suspect.6 Thus, according to the Phaedo, an adequate theory of causality must yield the right sort of stable relationship without which purported explanations crumble far too easily. Further, in the Phaedo, the Forms are explicitly presented as a hypothesis that would allow us to render the properties and changes of particulars intelligible, in the absence of the kind of teleological account that Socrates was hoping to get from Anaxagoras—​that is, one that appeals to goodness or beauty (100a2–​b9; cf. 101d1–​e3). In the Timaeus, a teleological account of the right sort is given, and it is in this context that Timaeus distinguishes different types of causality: one intelligent cause that aims at what is best, and another, “necessity,” that does not.7 In this way, Plato gives us the theoretical status and the theoretical context of his main claims about causality, as well as some relatively clear adequacy conditions for a good account of the causes of coming-​to-​be. Hume has a very different approach, of course, and his presentation enables us to see the resulting differences in second-​order thinking quite

5 See Strange 1985 and Johansen 2004, ch. 5. 6 See Phaedo 96e6–​97b7 for the point that the types of cause to which these earlier thinkers appeal are subject to this kind of instability, though its precise nature is controversial. For the inadequacy of explanatory principles that do not appeal to Forms generally, see Rep. V, 478e7–​479e5. 7 See especially Tim. 46c7–​47c4 and 47e3–​48b3. Necessity includes what is described as the “wandering” cause (hê planômenê aitia), as well as the notion of an auxiliary cause (sunaitia); on these and their relation to necessity, see Johansen 2004, ch. 5. Cf. also the general claim at 28a4–​6, that everything that comes to be (pan to gignomenon) does so necessarily by virtue of some cause.

Introduction  5 starkly: he thinks that we must come to terms with causation against the background of certain starting points concerning how anything at all comes to be present to the mind, which include a sharp cleavage between relations of ideas and matters of fact.8 Many post-​Humeans, in turn, present their views against the background of the challenges he raises for the notion of a necessary connection, and especially the problem of avoiding the kind of skepticism they threaten, including, most famously, Kant.9 In Aristotle’s case, however, the second-​order thinking is far less clear, despite the fact that he evidently thinks that his predecessors were not just incorrect about causes but were thinking about them in profoundly wrong ways—​and the standard presentation does not really help here either. I submit, then, that despite the abundance of texts and commentary we have about causes in Aristotle, we do not really have a good account of his theory of causality, in the sense I have described. In part I think this is because of the way causality permeates so much of Aristotle’s work, as mentioned at the outset—​so often the frame, so rarely the focus—​but there are other, more concrete reasons as well. Aristotle’s own presentation in those canonical chapters of Physics [Phys.] II is surely partly to blame. Even though these chapters are the ones most explicitly concerned with general theses about causality in Aristotle’s surviving works, they are not a philosophical inquiry into causes as a distinctive or disputed subject in its own right, the way, say, Phys. III 1–​3 is an examination of change (kinêsis), Met. VII an examination of substance (ousia), and Met. IX of actuality (energeia). Phys. II as a whole is concerned with nature (phusis) and the problems that arise in understanding it, especially as an object of scientific inquiry. In Phys. II 3, without preamble or obvious philosophical motivation, he simply says that, having discussed the notion of nature and how the natural scientist differs from the mathematician—​an odd-​seeming question to which I return later (§ 3.2)—​we should discuss the kinds of cause and how many there are (194b16–​17). He presents a list with some examples—​ some obviously appropriate, some unclear—​draws a variety of distinctions 8 See, canonically, Treatise I.III.II and Enquiry § 4.I. 9 More recently, many analytic philosophers have approached the question following the broad pattern applied to other general notions, with a focus on ordinary usage, the “method of cases,” and so on; see Paul and Hall 2013 for a sustained treatment. Others, approaching from the philosophy of science, build theories of causal explanation while eschewing the task of giving an analysis of causation itself, such as Woodward 2003, who rightly laments the fractured nature of contemporary discussions of causality across different sub-​disciplines (3–​4). Nevertheless, Hume’s critique continues to cast a shadow even over these other approaches.

6  Causality and Causal Explanation in Aristotle and sub-​classifications, and then moves on to a discussion of chance and luck (chs. 4–​6), before returning in II 7 to give a brief account of the way in which a natural scientist should approach causal explanation. In short, the standard presentation and its limits are no accident, since they mirror Aristotle’s own. Phys. II seems somehow both highly informative and philosophically silent at the same time, giving us a wealth of distinctions, examples, and specifications, but no arguments, no claims to insight, and no sense that what is being revealed here is the key to what everyone else missed.10 Another reason Aristotle’s theory is unclear is no doubt the pluralism that lies at its core—​indeed, it is pluralistic in ways that extend beyond the obvious fourfold distinction, as I shall argue. That pluralism has, along with modern assumptions about causation, made it possible to treat the modes separately, and so to assume that if Aristotle does aim to answer questions about causality, those answers lie in his claims about efficient or material causes. It also makes it more natural for scholars to examine topics in a piecemeal way—​to look at his account of the causes of substance (ousia), or teleological explanations in biological contexts, for example—​especially since for these topics Aristotle does indeed make his motivating concerns and his argumentation more evident. Finally, there is the persistent question of the relationship between Aristotle’s mature thinking about causality and natural science in the Physics and Metaphysics [Met.], on the one hand, and his account of scientific understanding in the Posterior Analytics [APo.], on the other.11 The latter work presents a theory of scientific demonstration with causality at its core: the 10 Aristotle does, of course, extensively discuss his predecessors’ views and point out their shortcomings relative to his own. In particular, Metaphysics I contains a rich source of understanding for Aristotle’s views about the defects of his predecessors’ theories; Phys. I presents a case for recognizing matter and form as principles of change, against the background especially of earlier accounts (and rejections) of change; and Phys. II 8 defends the idea that nature acts for the sake of something—​the thesis of so-​called natural teleology. But these piecemeal, and in some cases notoriously unsatisfying, discussions do not give an account motivating or defending the fourfold distinction itself either, nor do they tell us exactly how Aristotle’s conceptions of these causes are distinctive enough that it makes sense for him to say that in a way they have not even been discussed at all before him. In the Metaphysics the causes function as a lens for clarifying the nature of wisdom: his discussion of his predecessors confirms for us that, since no other modes of causality have been identified other than the ones described in the Physics, we can be satisfied with using them as organizing principles for the search for wisdom. He explicitly refers us to the Physics for a full discussion of the causes at Met. I 3, 983a34. The discussion of principles in Phys. I likewise tends to emphasize the similarities between Aristotle’s account and the “principles” of his predecessors (e.g., that they all recognize contraries as principles), rather than the differences. Finally, the enormously controversial arguments for natural teleology in Phys. II 8, on most readings, make use of a prior understanding of teleology which, he argues, extends to nature and natural things (see § 1.2). 11 The Posterior Analytics is universally regarded as an early work, and earlier than the Physics; Barnes 1994, xiv supposes it was written while Aristotle was still at Plato’s Academy.

Introduction  7 middle terms of demonstrations are supposed to pick out causes of what they demonstrate, and essences are among the first principles of demonstration. These accounts of demonstration and essence have much to say about causes and causal explanation, but they do not present a theory of causality as such—​for the most part the nature of causality appears to be taken for granted. Nor is it clear, notoriously, how exhaustive this account is meant to be as an account of causal explanation (i.e., of the ways in which we appeal to causes to render phenomena intelligible), or how much of it is meant to apply to Aristotle’s natural scientific work. Even if we do not claim, as some commentators have, that Aristotle abandons the Analytics model when he turns to natural science, we nevertheless cannot assume that the APo.’s discussion of demonstration is informed by Aristotle’s mature thinking about causality—​as we shall see, there are good reasons to think that it is not. Thus, there is a great deal of difficulty in linking Aristotle’s most sophisticated discussions of causality with his most developed account of scientific explanation, despite the prominence of causal notions in the latter. There are, then, good textual and philosophical explanations for the fact that it is difficult to discern a clear and unified theory of causality in Aristotle’s general remarks about causes, and for why scholars and philosophers have not reconstructed one. Yet he is explicit that his predecessors only had a partial grasp of whatever causal principles they did identify, and that his own achievement does not lie simply in having collected the whole set. Indeed, for each mode of causality, Aristotle is explicit that it has not just been imperfectly grasped, but ignored or outright rejected by some of his predecessors.12 Such an insistence makes little sense without some general reflection as to what makes for an adequate understanding of causality and causal explanation. Thus, we also have good reason to suppose that Aristotle does have a general theory, at least to the extent that what he says about causes and causal explanation is guided by a reasonably determinate sense of how his own views about causes are superior to those of his predecessors. Tracing this line of thought is the main goal of this book. Commentators have raised a number of interlocking questions, however, about whether, broadly speaking, it is appropriate to take Aristotle’s concerns with aitiai to match with our concerns about causes, which would imply that tracing this line of thought would not in fact yield a theory that is usefully compared with modern theories of causality. It is common, for example,

12 I discuss these passages in Chapter 2.

8  Causality and Causal Explanation in Aristotle to note semantic worries about whether ‘aitia’ really means or should be translated as ‘cause’, rather than ‘because’ or ‘explanation’. These worries are sometimes coupled or confounded with conceptual worries about whether Aristotle’s claims about aitiai (or Plato’s for that matter) should be interpreted as claims about causes (i.e., whether their concept of aitia, if they have one, is a match for our concept of cause, if we have one). There are, further, more theoretical worries about whether certain modern assumptions about causes are incompatible with Aristotelian or Greek assumptions about aitiai, which would suggest that the modern theoretical enterprise is in some important way different from the ancient one.13 The semantic claim by itself is not compelling as long as we do not insist that ‘cause’ must mean what recent Anglophone philosophers have taken causes to be, and so I will follow the tradition of translating ‘aitia’ and ‘aition’ as ‘cause’ except where noted.14 The more substantive worries about conceptual and theoretical overlap are not borne out either, as I hope will be clear from what follows. Even at this stage, however, there are good reasons to 13 For example, whether Aristotle’s efficient causes are “things that do things to other things,” as M. Frede 1980 contests, or whether final causes can genuinely be responsible for things that are temporally prior to them, or whether we must assume causes are events. 14 Occasionally ‘explanation’ is indeed better, but not because there is anything misleading about ‘cause’ in most contexts. For what it is worth, the Latin ‘causa’ apparently first entered several Romance languages as meaning “thing” (and is the ancestor of ‘chose’ in French, ‘cosa’ in Spanish); later, it re-​entered those languages, and English, as ‘cause’, with the technical sense from its use in medieval philosophical discussions, having been used to translate ‘aitia’ into Latin from the classical period onward (OED). There was thus no decision to use an antecedent English word ‘cause’ to translate Aristotle’s ‘aitia’; rather, ‘cause’ owes its usefulness as a translation of ‘aitia’ to its intimate history with the term. Discomfort with the usage seems to have begun only in the late nineteenth and early twentieth century, despite criticisms of Aristotle’s own distinctions stretching back to Theophrastus. Grote 1872 uses ‘cause’ throughout his book on Aristotle, without noting any particular difficulty or awkwardness of translation, and Mill 1872, in his Logic, is comfortable using ‘cause’ in his discussion of Aristotelian as well as “Scotch” causes. But Heath 1876 criticizes Mill for this usage, and Wicksteed and Cornford’s 1929 translation of the Physics warns us that “it does violence to the English idiom to call the material out of which a thing is made, or the distinctive attributes which define it, its ‘causes’. . . . Paraphrase or barbarism offer the only escape from using English words in a sense that they cannot really bear” (126–​27). Among recent commentators, Ross 2004, Ackrill 2001, 111, M. Frede 1980, Annas 1982, Barnes 1994, 89, Charlton 1992, 98, Hankinson 1998, 132, Lear 1988, 28, Moravcsik 1974, 1975, Santayana 1925, 183–​84, Sorabji 1980, 40, and Vlastos 1969, 294f. all note that the translation requires qualification in one way or another, but their claims range from minor caveats (Ross, Ackrill) to sharp warnings that the translation is deeply misleading (Vlastos, Frede, Annas). On the other hand, some commentators have remained unmoved: see, e.g., Gotthelf 1987a, Freeland 1991, and Furley 1996. Interestingly, the seventeenth-​century authors of the so-​called Port-​ Royal logic (Arnauld and Nicole 1981) make the opposite complaint about scholastic definitions of cause, which they claim are imprecise and do not seem to capture all of the kinds of cause, so that it is better to leave ‘cause’ undefined—​“l’idee que nous en avons étant aussi claire que les définitions qu’on en donne” (238). There is, of course, no point in arguing that ‘cause’ and ‘aitia’ mean the same thing, but nor do we make progress on the more substantive questions by suggesting that, for semantic or conceptual reasons, Aristotle’s claims about aitiai are really claims about something other than causes. For a clear survey of the history and evolution of the term ‘aitia’ itself, see Natali 2013.

Introduction  9 suppose that the basic problems underlying Aristotle’s inquiries are essentially the same as the ones underlying modern ones. There are many reasons for wanting to understand the nature of causality, but the presentation in Met. I expresses two of the central ones. First, causality is at the heart of explanation and the pursuit of knowledge or understanding, especially in natural science. A good account of causality, Aristotle clearly thinks, is required if we are to understand and justify a broad swath of our knowledge-​seeking practices; to say what kinds of explanation are good or bad, in what contexts, or for which topics; to distinguish genuine from pseudo-​explanations; to know what kinds of things can be causally explained, and what cannot; to know what can be explained at all and what must be understood some other way, or can only be described. Second, as Aristotle’s exposition makes clear, one’s approach to causality bears on fundamental questions about appearance and reality, and how they relate to one another. Imagine a debate between three parties: one tells us that to understand the appearances we confront in everyday life and in observing the natural world, we need to seek the material stuff that underlies those appearances and controls them from below; another tells us that we need to find the abstract patterns and ultimate realities that govern the world of passing appearances, which can only be grasped by the mind and not the senses. A third interjects, and tells us that the other two are both wrong: we can grasp and explain fundamental reality without “descending” or “ascending” to a different ontological plane, and yet still arrive at a profound type of understanding, as “scientific” or theoretical as we might wish, rather than a merely detailed description of the shifting appearances we call the natural world. This is a philosophically dramatic clash of viewpoints, and it is more or less the story Aristotle tells us about himself and his predecessors.15 He is explicit that a proper understanding of causality itself is what allows us to see this third way, yet we do not have his argument, really, as to how his own account of causality helps ground his contention. Like him, however, we tend to assume that ultimate reality and genuine causality go together, and it is common to argue that some phenomenon is mere appearance, or of ontologically lesser status, or epiphenomenal, because it is not causally efficacious or arises incidentally from different causal processes that are genuine.

15 Indeed, some of the puzzles in Met. II, especially the sixth (998a20–​b14) and eleventh (1001a4–​ b25), set up an opposition between the Platonist and reductive materialist approaches in just this way, such that the dissolution of the puzzle will require seeing how each is mistaken.

10  Causality and Causal Explanation in Aristotle Thus, while one might raise questions about the extent to which Aristotle’s accounts of aitiai fit with or diverge from contemporary accounts of causation, the motivations underlying his reflections on aitiai are of clear philosophical concern to us, and they connect very closely to basic questions about causality.16 In view of his pluralism and the broad but still limited scope he places on causal explanation, his view is also of interest to recent debates about the nature and scope of non-​causal explanation. There are two further motivations for trying to formulate Aristotle’s theory of causality in the unified way I have proposed. First, there are a number of persistent but seemingly more circumscribed puzzles and controversies in Aristotle’s work which, I think, are best understood and answered in light of a general theory of causality rather than independently of it. These include questions about the scope of his commitments to teleological explanation in nature, his understanding of causal powers and causal action, the nature of his essentialism, and his commitment (or lack thereof) to the so-​called Principle of Causal Synonymy (the principle that only something F can be a genuine cause of something else’s being F), as well as his frequent but sometimes obscure claims that formal and final causes are “the same” or “one.” It is valuable to pursue piecemeal analyses of various types of causal relationship in Aristotle’s work, but problems like these also call for a synthetic understanding that treats them in relation to a theoretical whole, absent any reason to think this cannot or should not be done. Second, Aristotle’s four-​causal framework is often identified as at the core of the pre-​modern, pre-​scientific view of nature that was abandoned or at least thoroughly revised by the scientific revolution. Even though it has been well-​established that the most radical versions of this way of reading the revolution are caricatures, there is an enduring supposition, even among philosophers and historians of philosophy, that somehow the Aristotelian conception of causality, especially in light of its commitments to hylomorphism and teleological causality, cannot really be separated from

16 These reservations about aitiai and causes should be further distinguished from the one considered in a moment, namely, whether Aristotle’s views about causes are so tightly connected to a pre-​modern understanding of nature that they do not apply in a modern scientific context. This question is important and substantive, but it is sometimes miscast as a question about whether Aristotle’s notion of aitia is really a notion of cause, or whether his word ‘aitia’ is appropriately translated by ‘cause’ in English. Given the philosophical motivations I have just described, the idea that for conceptual reasons, in his investigations of ‘aitiai’, Aristotle is engaged in a deeply different project than the one in which Hume, Kant, Mackie, Hart and Honoré 2002, Armstrong, Lewis 2000, or Woodward 2003 are engaged when discussing causation, simply is not true in any worthwhile sense.

Introduction  11 a pre-​scientific understanding of nature and its metaphysics.17 At the same time, when we read these chapters of the Physics or Metaphysics I, many of their main statements seem plainly reasonable. Indeed, for all the worries about their suitability for a modern scientific worldview, all of Aristotle’s four causes continue to be deployed in causal explanations in both scientific and philosophical contexts, in various guises, whether separately or together: material and efficient-​causal explanations often stand alongside teleological and functional explanations, various forms of essentialism are developed and defended, and many examples of what are now often called “grounding” explanations are recognizably types or descendants of what Aristotelians would have called material-​or formal-​causal explanation.18 But the problems that made Aristotelian views of nature seem inconsistent with modern science do not really turn on whether or not all of these relationships deserve the label of ‘cause’, so it remains unclear how and how much our own explanatory theories and practices are really different from Aristotle’s. Part of the difficulty in assessing those differences lies again, I think, in the fact that presentations of Aristotle’s account of causality tend to be so closely bound up with particular applications or cases, especially that of substance, that it is simply not clear how much paradigmatically Aristotelian metaphysics is really embedded in Aristotle’s claims about causes.19 An account of Aristotle’s theory of causality therefore holds the promise of clarifying more local questions about his views, as well as answering broader questions about the continuities and discontinuities between ancient, medieval, and modern scientific approaches to the natural world and our understanding of it.

17 For an account of the development of early modern science which is sensitive to the ways in which it was and has been taken to reject various strands of Aristotelian natural science, see Shapin 1996. For an account of some key developments between Scholasticism and early modern conceptions of causality, see Schmaltz 2008, 2014. For a survey and analysis of different historical claims about “the Scientific Revolution” and its relation to Aristotelianism, see Cohen 1994, ch. 4. 18 The nature and scope of “grounding explanations” are controversial and the subject of an ever expanding literature. See the contributions in Raven 2020, many of which note the connections to Aristotle and other ancient authors. 19 To cast some doubt on this tendency, it is enough to note that Aristotle only mentions substance (ousia) once in Phys. II 3–​9, and only to make the point that a teleological explanation should explain something in virtue of its being better not unqualifiedly, but in relation to a substance. This is the very last line of c­ hapter 7 (198b9). There are only a handful of other uses in book II, all of which are in ­chapter 1, which is a dialectical study of the notion of nature—​a context in which Aristotle often uses the term for substance in describing the views of his predecessors.

12  Causality and Causal Explanation in Aristotle

I.2.  Outline This study thus has two main motivations: to understand Aristotle’s theory of causality in the philosophical context of his critiques of his predecessors’ views about causation and causal explanation, and to understand it in such a way that it can fruitfully be considered as a philosophical approach alongside broadly Platonic, Kantian, and Humean approaches. These aims are interdependent, of course. Because of the various ways in which causality permeates Aristotle’s work so thoroughly, however, it can seem as though such a project would require nothing short of a full reckoning of his theoretical philosophy, and so would in the end accomplish little. Nor can we dismiss the skeptical hypothesis that Aristotle does not really have a full-​blown theory, as opposed to a reasonable and flexible framework that he applies and extends in a piecemeal way—​not randomly, but not because of any overarching general account of causality, explicitly or implicitly held. I think, however, that we can see a general theory at work that answers to these main motivations, and that we can isolate the basic elements of his answers to these main philosophical questions we tend to raise about causality, especially in light of the ways Aristotle himself raises and recognizes them. The only way to decide the question is to see what results from the attempt. My strategy is first to animate the key chapters about causality, namely Phys. II 2–​9, but especially 2–​7.20 As I have noted, these chapters present Aristotle’s distinctions without philosophical motivation or defense, but we can see what they accomplish, in theoretical terms, by reading them against their philosophical background, particularly the criticisms Aristotle makes elsewhere of his predecessors that connect most directly to questions about causality, as well as the general constraints concerning causation and explanation that he describes in other works, such as On Generation and Corruption, the Metaphysics, and the Posterior Analytics. Against this background, several features of those key chapters stand out, which allow us to delineate some important conceptual claims Aristotle makes about causes, and which govern the four-​causal framework as a whole. This is the task of Part I. 20 While Phys. II 3 contains the canonical presentation, II 2 has already, in responding to the demarcation challenge in relation to mathematics (discussed below), introduced some key points about all four modes of causality.

Introduction  13 In each of Parts II and III, I then frame a primary question about causality which is also at the heart of Aristotle’s critique of his predecessors, and argue for an interpretation of the way the views in Phys. II and III express commitments that respond to those questions and problems. Part II raises a metaphysical question, while Part III focuses on an epistemological one. In more detail, the three parts of the book run as follows:

I.2.1.  Part I After briefly discussing the canonical chapter of Phys. II 3 and the problems it raises, both by itself and in the context of the whole line of discussion in Phys. II (Chapter 1), I turn to an examination of Aristotle’s criticisms of his predecessors, focusing especially on criticisms that relate to causality (Chapter 2). Those criticisms mainly divide into two sorts. Some are motivated by worries about how the natural world can be a genuine object of scientific understanding (e.g., in light of worries about whether something fundamentally characterized by change and instability, as nature is, can be fully understood). Others relate to metaphysical worries about the relationships between certain types of proposed causal principle and the phenomena of which they are claimed to be causes. Next, I turn to a different set of background philosophical considerations pertinent to Phys. II 3, having to do with general constraints on explanation and explanatory practice (Chapter 3). I then return to Phys. II 2–​7 to highlight the philosophically significant claims of these chapters against this background, and I assess their implications for my main questions (Chapter 4). Three key interpretive claims emerge from this part, which in different ways reflect Aristotle’s critiques of his predecessors’ views: (1) Aristotle, I think, diagnoses many of the problems with his predecessors’ accounts of nature as stemming their commitment to a kind of reductionist approach, requiring what I call a special metaphysics for causal explanation. This approach typically connects causal explanation with a special ontology and/​or privileged relationships to such an ontology. This reductionist approach, as I argue, is pursued in different ways by Platonists and materialists alike, though its precise

14  Causality and Causal Explanation in Aristotle nature, and the problems Aristotle sees with it, must be distinguished from other types of reductionism. (2) The schema presented in the Physics represents an extension of a simpler schema given in Posterior Analytics II 11—​simpler in that it appeals to fewer and more basic concepts. That simple schema presents four ways of accounting for a situation in which something answering to a predicate is said to hold of some subject—​that is, in some appropriate sense of the term, a fact. Phys. II 2–​7 take these distinctions and extend them to the task of explaining things and the changes they undergo rather than true predications, in particular to the more controversial task of stating the causes that are intrinsically (kath’hauto) connected to stable kinds of change or thing, whether natural or artificial—​that is, to things that are not co-​incidences or otherwise unique.21 (3) While Aristotle’s four-​causal schema is often loosely described as being comprised of four distinct metaphysical roles or relationships, this is inaccurate and misleading in important ways. They are rather what I shall call second-​order roles, since they each cover what Aristotle thinks of as clusters of importantly different and more determinate metaphysical roles and relationships—​and the differences matter a great deal for a variety of reasons that have not been appreciated. Thus, the schema in Phys. II represents an ambitious extension of a logically more basic (and possibly earlier) schema for explaining facts of any sort, to a more metaphysically committed task of explaining

21 Here and throughout the book I use ‘intrinsic’ as a placeholder translation of ‘kath’hauto’, following Irwin 1988, Freeland 1991, and Meyer 1992, among others—​and only in this way except where noted. ‘Kath’hauto’ (“with respect to itself ”; often translated ‘per se’ or ‘in its own right’) is usually contrasted by Aristotle with ‘kata sumbebêkos’, literally something like “with respect to being placed or occurring together,” often translated by ‘per accidens’, or ‘accidental’, ‘incidental’, or ‘co-​ incidental’. It is also contrasted, more rarely, with ‘kath’heteron’, for example, at De An. I 3, 406a4—​ “with respect to another,” or ‘per aliud’. I discuss some of these contrasts later in § 3.1. These are all quasi-​technical terms, and Aristotle’s use of them is sometimes flexible or unclear; all translations have their own drawbacks. ‘Intrinsic’ is similarly quasi-​technical, and usually not bad, but it should above all not be taken to imply that something is internal. In Aristotle’s translated usage, then, a doctor is normally an intrinsic and external cause of health in a patient, and so Aristotle’s claim in Phys. II 1 is that to have a nature is to have an intrinsic origin of change which is also internal in some important sense. There is a modern usage of ‘intrinsic’ in relation to causation which is different, though, I think, adjacent to this one; for that sense see, e.g., Menzies 1999, Hall 2004b. I will use ‘co-​incidental’ for ‘kata sumbebêkos’, since ‘intrinsic’ requires a contrasting English term, and I am reserving ‘extrinsic’ for broader work (see again § 3.1); here again the term is something of a placeholder, since not everything that ‘co-​incides’ with something else in this usage is a mere accidental concomitant.

Introduction  15 regularly occurring phenomena in terms of their intrinsic causes. It is nevertheless far more metaphysically neutral than it may appear and is often presented.

I.2.2.  Part II The metaphysical neutrality of the schema in one sense makes it flexible but also raises worries about explanatory power. If there is no special metaphysics for causality, what account can we give of the relations between causes and what they cause? These worries derive from a more general set of tensions surrounding the metaphysics of causation, to which Hume’s famous rejection of the notion of “necessary connexion” is one kind of response. The tensions are broadly due to the fact that causes and effects are somehow supposed to be connected tightly enough to ensure that their relationship is not one of mere co-​incidence or regular co-​occurrence, but not so tightly connected that the phenomenon collapses into a kind of self-​realization of an effect. Finding an acceptable compromise between these various pulls is, I suggest, one of the main problems for giving a good account of the relationship at the core of the metaphysics of causality: that between causes and what they cause. Aristotle himself, in various guises, raises some of these same concerns for his predecessors. How, then, does he think causes in nature relate to what they cause, and how can his account avoid the metaphysical problems he raises for his predecessors that pertain to the tension I have described? Since Aristotle, on my account, rejects the appeal to a special ontology for causal explanation, and since he is also committed to a kind of metaphysical pluralism within each mode, he does not think that there is one universal kind of connection between, say, material causes and what they cause. Rather, I argue, his position involves extending the features commonly associated with essentialism about natural kinds to the whole range of regular phenomena that have intrinsic (i.e., kath’hauto, or per se) causes (Chapter 6). These include not just substances and the processes by which they are generated and destroyed but also those changes, activities, and states of affairs which always or usually occur in the same way, by the same causes. For these phenomena, too, the natural scientist should give a so-​called real definition, that is, one which specifies what they are by stating why they are—​ by stating their intrinsic causes. I argue that Aristotle does just that for different kinds of change, giving a brief and cryptic statement of how this is to

16  Causality and Causal Explanation in Aristotle be done in Phys. III 3, and following precisely the suggested model in certain key cases, especially clearly in his so-​called chemical work, Meteorology IV. Clarifying this point requires finding a path through a thicket of philosophical and interpretive difficulties about essences and the different types of definition and definienda Aristotle recognizes. Aristotle further recognizes, I argue, different types of what I call “causal profile,” corresponding to different types of regularly occurring phenomena with different arrays and types of causes (Chapter 7). As on many standard presentations of the four causes, some natural phenomena do indeed have all of their causes intrinsically, the way substances do. Many, however, do not, and even among those that do, there are important differences in the ways the causes of a causally defined kind relate to each other, and to the phenomenon they explain. I argue that Aristotle observes an especially important distinction between what I call “origin-​dominant” and “end-​dominant” causal profiles. This distinction is expressed briefly but relatively clearly in Met. VII 17, though Aristotle does not go into detail. When we elaborate on this distinction, however, we can offer satisfying interpretations of some persistently difficult questions and passages, including the nature of his commitment to the so-​called Principle of Causal Synonymy, and the various passages in which he seems to identify the formal and the final causes (on which see the final section of Chapter 7). I then return (Chapter 8) to the challenge of accounting for the various features of causal relations that seem to be in tension. Focusing especially on the question of discreteness between efficient causes and what they bring about, I articulate the components of a transeunt-​causal change (i.e., a change brought about in one thing by something else) and how they relate to the change itself. Several distinctions then need to be drawn between different ways in which things may be considered discrete or not discrete, and these in turn need to be applied to the different components Aristotle recognizes in a causal interaction, as well as the distinction between actuality and potentiality. The resulting response to the question of discreteness is quite complex, but that complexity is an inevitable function of several key features of Aristotle’s view. Rather than admitting a simple answer, which would be inappropriate given the complexity of the phenomena, the question of discreteness and the distinctions drawn allow us to see how Aristotle negotiates the different demands we face in giving a good account of causal interactions.

Introduction  17

I.2.3.  Part III Finally, I turn to questions about the epistemology of causality. These issues are, I think, as important as any of the others, but perhaps the least developed in Aristotle’s work, as well as that of his commentators.22 The problem, in effect, is one of appearance and reality, or the relationship between the so-​called manifest and scientific images of nature. As I argue (Chapter 9), in Aristotle’s terms, this is the problem of moving from what is “more knowable to us” (gnôrimôteron hêmin) to what is “more knowable by nature” (gnôrimôteron phusei), or “more knowable without qualification” (gnôrimôteron haplôs), and how causality figures in this transition. That Aristotle takes this question very seriously is clear, but the brief texts in which he confronts it directly are some of the most cryptic in the whole corpus, and the commentary tradition, understandably enough, largely follows the texts. Describing his account is therefore necessarily more of a reconstructive effort than that of the previous sections. Each point I make has a firm basis in the texts, however, while building on what I take to have been established in Parts I and II, and the view that results is a recognizably Aristotelian one that fits with his main philosophical commitments. I focus especially on aspects of what is “more knowable to us”—​the manifest image—​and how Aristotle thinks we progress from it to a grasp of causes, in such a way that he would have reason to claim that his views make a scientific grasp of nature possible in ways that his predecessors’ do not. The main elements of my account are that (1) there are epistemic asymmetries among different modes of causality and with respect to different causal profiles (Chapter 10); and (2) at least some causality is such that it can be grasped with our more basic cognitive powers of observation, that is, without inference and without going beyond the conceptual resources available to ordinary perceptual judgment (Chapter 11). Some causality is, we might say, just as it appears, at least to careful observation, and so for these phenomena there is no necessary gap between appearance and reality. To illustrate the view as a whole and use it to clarify some of Aristotle’s claims about particular natural phenomena, I examine Parts of Animals II 2–​3, which is concerned with how we should approach a scientific understanding of the nature of blood, and, finally, connect that account back to some of the problems raised by Aristotle’s remarks on induction.

22 Claims about causal inference are, of course, at the heart of Hume’s critique as well.

18  Causality and Causal Explanation in Aristotle Thus, in contrast to what I take to be the implication of most readings of Aristotle as well as a standard contemporary picture, understanding the causal structure of the natural world is not a matter of moving from an image that lacks causal content or causal concepts to one that does. That picture of epistemic progress fits more naturally with the kind of appeal to a special metaphysics for causal explanation that Aristotle rejects. Nor are all four causes epistemically on par with one another. Rather, I argue, the path from the most basic to the most sophisticated kinds of causal knowledge is anchored in non-​inferential knowledge of certain kinds of cause and causality, and it is marked by different and more sophisticated causal concepts as it progresses.

I.3.  Themes, Consequences, Comparisons, and Absences As the summary in the previous section makes clear, pluralism is a recurring theme. Aristotle is not just a pluralist about the modes of causality, but about the different types of relationship within the various modes between causes and what they cause, and about the different types of epistemological task we confront in coming to know them. This is thoroughly in character for a philosopher who generally seeks to observe salient differences among general groupings, and to privilege the more determinate specifications of lower-​level kinds over highly general and, he thinks, often deceptively uninformative accounts. These pluralistic commitments are important for many reasons, but a central one I think is this: Aristotle thinks that if we follow the approaches of his predecessors, the best we can achieve is a kind of “co-​ incidental” knowledge of natural things—​that is, we can only know them indirectly, and therefore only in a qualified way. If natural phenomena are to be objects of scientific understanding in their own right, however, we must be able to know them unqualifiedly—​hence, not just in relation to something else—​and this, he thinks, requires a more articulated approach to causation that can allow for different types of explanandum, the knowledge of which places correspondingly different cognitive demands on us. Another theme is that Aristotle’s views about causality are often studied and assimilated too closely with his views about especially important cases of causally explicable phenomenon, most prominently substance. Indeed, part of what motivates this book is the thought that Aristotle’s claims about causality have suffered not just from their presentation, but from a subsequent

Introduction  19 failure to disentangle them from these more prominent applications of causal analysis. Substance is indeed basic on Aristotle’s view in many ways. For this reason, however, it is not only difficult to understand and a source of persistent controversies, but it also lies at the extreme end of the spectrum of natural beings in a way that makes Aristotle’s causal concepts harder to clarify. We can do better in that regard by attending to the full range of phenomena Aristotle thinks admit of genuine causal explanation, and indeed, since Aristotle ultimately aims to understand substance in light of causality, we can gain a better understanding of his views about substance as well if we can tease the two apart.23 I have taken my primary task to be arguing for the account of Aristotle’s theory itself, rather than about whether it succeeds or how it compares with other accounts, and so this introduction has largely followed that line of argument. Along the way, however, I do draw connections, raise and consider objections, and make some assessments of the view. One theme of those sections is that, if Aristotle’s theory of causality has modern relatives or at least natural friends, they are in the family of views in recent philosophy of science known as “neo-​mechanism.”24 That connection is rarely noted in the scholarly or philosophical literature, but Aristotle and the neo-​ mechanists share similar motivations—​to avoid reductionism and to frame causal explanations that respect the contours of the phenomena they are addressing—​as well as the view that natural phenomena are often complex wholes made up of simpler, causally interacting processes which always or usually occur in the same way. I discuss the similarities and differences especially in § 8.6. Another main “exoteric” theme is that comparing Aristotle’s view to modern ones is often very fruitful, but rarely direct. When we understand what he claims and what he does not claim about causation, I think two aspects of his view stand out especially clearly in contrast with a pair of related assumptions common to a great deal of contemporary work. One is

23 For similar reasons I have also paid less attention to the difficult topic of the inter-​transformation of the elements, especially since it is bound up with the question of prime matter. For a recent study of that question, see Lewis 2008. Likewise, I have tried not to use artifacts as primary illustrations as far as possible, since their role as models for substance and for causality more generally is easily tangled. Causality in general, I submit, is seen most clearly through examples in between these extremes of substance and prime matter, which lie at the limits of natural science, as Aristotle conceives it. 24 Perhaps the most prominent contribution is Machamer, Darden, and Craver 2000, but see also Glennan 2016 and Craver and Tabery 2019. For a useful survey, see Andersen 2014a, b. These views and their relationship to Aristotle’s should be sharply distinguished from views known under the more standard “mechanist” label. Aristotle’s relationship to mechanism in that sense is discussed in Berryman 2009.

20  Causality and Causal Explanation in Aristotle the assumption that giving a genuine, scientific account of nature involves moving from the “ordinary” ontology with which we are presented in everyday life to a special ontology consisting only of objects which meet certain more stringent criteria for existence or causal power. A version of this assumption is held, he thinks, by the materialist and Platonist reductionists whose approaches he rejects, but, of course, the manner in which he rejects the assumption depends on how he construes their views and his own. The other is the common and related assumption that causal relations somehow supervene on non-​causal facts, events, or states of affairs, such that giving an account of causation amounts to analyzing the relationship between these basic, non-​causal facts and the supervenient causal ones.25 That assumption has clear and profound implications for discussions of the metaphysics of causation, and less clear but equally profound implications for questions about the epistemology of causation. I think that Aristotle rejects it, and has decisive reasons to do so. Since I have attempted to trace Aristotle’s theory of causality in argumentative context, there are a number of other issues one might expect to be discussed in a book about Aristotelian causality which are not. These include the role that notions of necessity play in Aristotle’s account of causality, his theory of motion (including projectile motion, with its notorious problems), and theology, all of which have been given attention in their own right. Further, for the reasons given earlier, I have discussed substance and attendant questions about hylomorphism only as much as necessary for the argument.26 The position as I have sketched it in this introduction in some ways necessarily seems more complex than its underlying philosophical motivations. 25 This view and its status are shown very clearly by Paul and Hall 2013, who present their general survey as assuming “a broadly reductionist outlook, according to which facts about which events cause which other events are fixed, somehow, by (i) the facts about what happens, together with (ii) the facts about the fundamental laws that govern what happens. Minimally, that’s a supervenience thesis: no two possible worlds differ with respect to what causes what without differing with respect to what happens or with respect to what the fundamental laws are that govern what happens. But, as will become apparent, the most important philosophical approaches to causation aim for something arguably stronger, namely, an account of causation that lays bare the causal ontology in terms of how causal facts are grounded in, reduce to or depend upon these more basic facts” (7–​8). 26 Likewise, I do not discuss some topics that are prominent in recent discussions of causation, since they are not of central importance to clarifying Aristotle’s theory. These include questions about whether causation is transitive, whether absences can be causes, whether causes must be prior in time to their effects, and how causal relations should be “modeled.” In some cases, I think relatively clear answers do result from the theory as I have reconstructed it (as, for example, for the question of simultaneity, which should be clear by the end of Part II), while in others the question may simply lose its relevance, since some modern questions only result from adopting a certain framework.

Introduction  21 Because of his pluralism and his tendency to prefer causally determinate levels of specification to general ones, Aristotle’s views often resist easy summary. But the philosophical import of the position and the motivations behind its pluralism are reasonably straightforward. Against the persistent tendency to look for explanations behind, outside, above, or below the appearances, which ultimately treat them as somehow only of diminished status, Aristotle presents a picture according to which the things that we confront in the appearances are themselves primary realities, even if they are usually not ultimately just as they appear. His response to the various kinds of explanatory reductionism is a version of Butler’s dictum that “Everything is what it is and not another thing,” and one of his aims is to show that this response still leaves room for a scientific understanding of those realities that is profound, and does not consist merely in redescribing the way things appear. Some parts of the picture I present are heterodox, some are not, but the picture as a whole is perhaps neither heterodox nor orthodox, since, for the reasons mentioned earlier, I do not think there is a clear orthodoxy. There has not been a place at the table for an account of the whole, and there really should be.

PART I

C ONC E PT UA L STRU CT U R E

1 Reading (and Animating) Physics II 3 1.1.  The Problem of Physics II 3 In formulating the most basic questions about Aristotle’s four causes, both as constituting a theory and as a response to certain problems, we are at a disadvantage. The chapter in which the four causes are presented, Phys. II 3, does not argue for the distinctions, nor are they presented in any explicit context of dispute or inquiry into the nature of causes. As Ross (1936) says, “We do not know how Aristotle arrived at the doctrine of the four causes; where we find the doctrine in him, we find it not argued for but presented as self-​evident” (37). Our textual evidence is a series of statements of varying clarity, the philosophical aims and motivations of which are not apparent. After introducing his topic in Phys. II 1 as the study of nature, clarifying what he takes this to imply, and then distinguishing the natural scientist from the mathematician in II 2, Aristotle simply says: Having distinguished these things we must examine causes, both what sorts there are and how many they are in number. For since this inquiry is aimed at knowing, and we do not think we know each thing until we grasp the Why for each thing (and this is to grasp its primary cause), it is clear that we must also do this concerning generation and destruction, and every natural transformation (metabolê),1 so that knowing their principles, we may attempt to refer each of the things being investigated back to them. So then, one way in which ‘cause’ is said is as that out of which something comes to be and which is inherent2 in it; for example, the bronze of 1 Translating Aristotle’s terms related to change is difficult: he recognizes three canonical forms of ‘kinêsis’—​increase/​decrease (auxêsis/​phthisis), alteration (alloiôsis), and locomotion (phora); these are included under the even more general heading of metabolê, which also includes generation and destruction (see Phys. V 1 for the canonical distinctions). He does not always seem to observe the differences strictly. I use ‘change’ for ‘kinêsis’ throughout and choose ‘transformation’ as the least awkward for ‘metabolê’, but where the terminology matters I will provide Aristotle’s term in parentheses. 2 ‘Enuparchontos’ also presents some difficulties of translation, which in the end are difficult to disentangle from philosophical questions about the nature of matter in a hylomorphic compound.

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0002

26  Causality and Causal Explanation in Aristotle the statue and the silver of the cup, and the genera of these things. Another way is the form, i.e. the paradigm, and this is the account of the essence, and its genera (for example of the octave, the ratio two-​to-​one, and in general number), as well as the parts in the account. Further, the primary principle from which the transformation or rest originates: for example, the person who has deliberated is a cause, and the father of the son, and in general what makes (to poioun) of what gets made and what transforms (to metaballon) of what gets transformed. Further, as the end: and this is that for the sake of which, for example, health of walking about. For when asked, “Why does he walk about?” we say, “in order to be healthy,” and speaking in this way we think we have given the cause. And however many things come to be leading up to the end, when something else is bringing about the change, for example, of health, slimming or purging or medicines or instruments—​all these things are for the sake of the end, but they differ from one another by being some of them functions and some of them instruments. So then, the causes are spoken of roughly in this many ways, and it follows that, as the causes are spoken of in many ways, there are also many causes of the same thing, not co-​incidentally; for example, both sculpting craft and the bronze [are causes] of the statue, not in accordance with anything else [ou kath’heteron ti] except insofar as it is a statue, though not in the same way, but rather the one as matter and the other as the origin of the change. (194b16–​195a8)

This text provides the most detailed description in the corpus of the four causes as a group.3 The rest of the chapter presents:

The example of metal suggests not just something present in what comes to be, but that the material is somehow continuously the same sort of thing from beginning to end. This seems incorrect for many cases such as biological generation, making translations such as ‘component’ (Reeve 2018) or ‘persistent’ (Hardie and Gaye in the Revised Oxford Translation) appear too strong (see Henry 2019, chs. 2–​3). In any case, given Aristotle’s examples later in the chapter and the philosophical questions he works through about matter here and elsewhere, we should not expect the term itself to be especially committal. 3 It is not immediately clear whether the fourfold distinction implies that ‘aitia’ is a multivocal term, i.e., ‘pollachôs legomenon’, or whether Aristotle might have another kind of multiplicity in mind, such as genus/​species relations. Here he mainly speaks of “ways” (tropoi) of being causes, but he does also say that they are “spoken of in this many ways” (195a3); at 195a29 he says that ‘aitia’ is pollachôs legomenon, but where this is not to indicate the main fourfold distinction. Elsewhere he uses the language of multivocity more explicitly; see, e.g., DA II 4, 415b8–​9, Met. I 3, 983a26–​27, and Met. VIII 4, 1044a33. There is some variation in his expressions, however: we find “forms” (eidê) of causes at Met. II 2, 994b28, and “kinds” (genê) at Met. III 2, 996a19–​20. I discuss the nature of this pluralist commitment in Stein 2011, though I revisit the issue here from a somewhat different

Reading (and Animating) Physics II 3  27 (1) Some entailments of drawing these distinctions among the causes (195a3–​14); (2) Confirmation that all the things that are “now” or “in fact” called causes fall under these four headings (195a15–​26); (3) A further set of distinctions among the ways in which causes and “effects” are specified, resulting in what he claims is an array of six main possibilities.4 Causes may be specified as follows: particular or general; particular co-​incidental or general co-​incidental; simple or complex. Each of these may be further specified as either actual or potential (195a26–​b21);5 (4) Some further claims about how causes should be pursued or specified (195b21–​30). This presentation is thus in some ways very detailed and informative, but philosophically inanimate, in that Aristotle does not argue for these claims and distinctions, nor does he provide a sense of what motivates or justifies them either in general or in context, so that even the seemingly informative parts turn out to be somewhat obscure. (Why, e.g., is it important to say that one way (tropos) of being a cause is as a co-​incident, and that Polycleites is in this sense a co-​incidental cause of a statue?) Indeed, Ross’s statement actually goes slightly beyond what we can say about the four causes, given Aristotle’s presentation. Though it is common to call it a doctrine, as Ross does, if we do not have a clear sense of why we are meant to accept these claims or what their precise import is—​nor who ‘we’ refers to when he says that “we do not think we know each thing until we perspective in § 4.3; the variations in expression may indicate genuine ambivalence, which would fit with my account. See also Gourinat 2013, § 1. 4 For convenience I will use ‘effect’ to refer to what causes are causes of, regardless of category or kind; Aristotle himself does not generally use a single word for what causes cause, but occasionally uses an equivalent periphrasis (e.g., ‘those things of which the causes are causes,’ as at Phys. II 3, 195b7), and we do find ‘what is caused’ (to aitiaton) at APo. II 16, 98a36 and 98b3. 5 Particularity and generality are initially referred to as ‘prior’ (proterôs) and ‘posterior’ (husterôs), but re-​glossed immediately below at 195b13–​14 as particular (kath’hekaston) and general (hôs to genos); co-​incidental causes may also be “farther” (porrôteron) or “nearer” (egguteron), which may be a matter of whether they are “directly” co-​incidental to the cause as such or co-​incidental to a co-​incident (see Ross 1936, 512–​13). ‘Co-​incidental’ brings in an implicit contrast with what is intrinsic (kath’hauto), subsequently made explicit by referring to intrinsic causes as causes “properly speaking” (ta oikeiôs legomena). The final distinctions are being spoken as potential (hôs dunamena) and as active (hôs energounta). Some of these terms are ones Aristotle uses consistently for talking about causes, but others are rare, and the language varies even within the passage. It is not entirely clear how to take some of them individually, nor what the aim is of the set of distinctions as whole; I discuss the latter question in § 8.2.

28  Causality and Causal Explanation in Aristotle grasp the Why for each thing”—​then we also lack a clear sense of their overall status. Do they constitute a metaphysical theory, a reflection of common beliefs, a survey of ordinary Greek usage, a “model,” claims resulting from a long examination of nature and especially natural substance, or something else? All these have been suggested, though some are less plausible than others.6 While the distinctions among causes are presented without argument or justification here, they are not supposed to be merely obvious to anyone without the right philosophical background—​they are not “self-​evident” in the strong sense. Indeed, Aristotle is at pains to point out, especially in Met. I and Phys. I, that they take a fair amount of thought to grasp clearly, and the confusions he attributes to his predecessors about them are not minor. Further, his claim that in one way all four causes have been described before, but in another way they have not been described at all (oudamôs), makes little sense if they are supposed to be self-​evident. Nor do they appear to be the results of analyzing ordinary talk.7 Some of the examples Aristotle gives are simple and ordinary enough, such as perhaps the examples of efficient and final causation—​though the example of the deliberating person is less obvious. However, this does not apply at all to the example of essence (the ratio of the octave) or in general the distinction between form and matter, which Aristotle has only just worked through in such a dialectically complicated way in Phys. I. Nor are the intellectual defects of his predecessors described in Met. I attributed to a failure to mark ordinary modes of speech. Ross’s tentative suggestion, that the doctrine is the result of considered reflection on natural and technical processes, aided by his grasp of the work of his predecessors, is no doubt more likely, but still vague. It may also understate the extent to which the context is Academic: as both he and Charlton

6 See, e.g.: Ross 1936 (reflections on nature and artistic production, with some help from his predecessors); Graham 1987, chs. 3 and 6 (a “model”); Irwin 1988, § 51 (common beliefs); Charlton 1992, 99 (ordinary Greek usage); Hennig 2008 (metaphysical theory). Exacerbating the difficulty is probably the fact that Phys. II 3 and its distinctions are so familiar to readers of Aristotle, and so pervasive, that it can be hard to avoid reading uses and problems from elsewhere in the corpus back into the presentation here. 7 Pace Charlton 1992, who claims that “it is obvious . . . that the doctrine with which we are presented here is the immediate result of a survey of how we ordinarily speak” (99), thus suggesting that the ‘we’ is either “we Greeks” or “we humans who speak about such things,” and that the distinctions are justified to the extent that they capture distinctions observed by ordinary speakers. (He cites Wieland 1962 as well as Phys. 194b24, b34–​35, and 195a3–​4, 15; but these passages are not compelling and only involve formulae that Aristotle uses in both technical and non-​technical ways.)

Reading (and Animating) Physics II 3  29 point out, Aristotle’s exposition contains a rare use of ‘paradeigma’ to indicate the formal cause, suggesting an audience familiar with Platonism.8 This discussion, as I have suggested, hardly answers the questions we would like to have answered: Why should we believe that there are four types of cause, and that they are these four? What philosophical problem or problems do these distinctions allow us to solve, which previous thinkers were unable to solve? What did they get wrong that Aristotle has gotten right? What, specifically, does this discussion accomplish? Yet this chapter, along with Phys. II 7, is clearly the canonical statement of the causes and their role in natural science (as the reference to his discussion in the works on nature at Met. I 3, 983a34 suggests). I think that we can illuminate the status and philosophical import of these claims by viewing the chapter in three contexts: (1) the whole of Phys. II; (2) the criticisms, in other works, of his predecessors’ accounts of causes that reflect his views about their more substantive mistakes; and (3) background debates and discussions about explanation and causation in general, and in natural science in particular. After all, despite its lack of argumentation or philosophical stage-​setting, it is a reasonable working assumption that Aristotle’s canonical presentation of the causes in Phys. II would show traces, in some fashion, of the results of his reflections about causes in general and the improvements he thinks must be made to the work of his predecessors. By placing the chapter in these three contexts, I think it will become clear that the common way of presenting the four-​causal schema, as primarily grounded in considerations of the causes of things such as substances and artifacts, though to some extent prompted by Aristotle’s own presentation, has it conceptually backward. Applying the four-​causal schema to things and the changes they undergo represents an extension of a conceptually more basic theory about the ways in which, and the means by which, predicates apply to their subjects—​namely, in virtue of the subjects themselves, or in virtue of something else.

1.2.  Physics II 3 in the Context of Book II Placing Phys. II 3 in its local context will help illuminate some of the content of its claims as well as their status, since I think one of the sources of 8 Cf. Natali 2013, 51.

30  Causality and Causal Explanation in Aristotle confusion is that it is often unclear whether Aristotle is making a general claim about causation or a more restricted one that depends on further metaphysical commitments. Though the transition from Phys. II 2 to II 3 is not philosophically straightforward, it is not completely abrupt either. As whole, book II presents a case for a specific understanding of natural science as the study of a relatively expansive array of things with “natures,” conceived of as enmattered forms—​ a nature being an internal source of various sorts of regular change and transformation—​and which are intrinsically rather than co-​incidentally related to the results they produce.9 A discussion of causes, then, is necessary in order to formulate claims about the phenomena with which the natural scientist is concerned, and the ways in which they are scientifically intelligible. Book II orients its initial questions about nature with respect to the possibilities yielded by book I, which has established that the “principles” (archai) of natural science are form, subject, and privation, in the sense that these are the basic concepts that make change, or changeable being, a possible object of inquiry.10 In laying down the principles of something called phusikê, and, even more boldly, the epistêmê of nature (Phys. I 1, 184a15) or phusikê epistêmê—​the scientific understanding of nature—​it should be kept in mind that Aristotle is describing something whose status is either contested or at least uncertain: Aristotle thinks that on principles like those embraced by a monist like Parmenides or a materialist like Empedocles, the very idea of natural science is unintelligible.11 More explicitly, Plato has 9 For recent discussions of the definition of nature in Phys. II 1, see Kelsey 2003, 2015; Stavrianeas 2015. 10 On the possible relationships between books I and II and the rest of the Physics, see Ross 1936; Menn 2019. 11 Aristotle’s terms ‘cause’ and ‘principle’ are sometimes extensionally equivalent, but they interact in complex ways, especially in connection with questions like this one about what we might call the “conceptual foundations” of natural science. As he says in Met. V 1 (1013a16–​17), all causes are principles, since what is common to all the main uses of ‘principle’ is that they are the “first things from which [something] is or comes to be or is known” (18–​19); however, not all principles are causes (in that sense). ‘Principle’ is the conceptually broader term, which is why Aristotle can elucidate the notion of nature as a cause, and indeed the role of efficient causes in general, by telling us what kind of principle they are. He also uses the term to indicate conceptually fundamental notions or theses, such as the ultimate starting points for demonstration (see APo. I 2, 72a7f., and I 10 for discussions of demonstrative principles). Since Aristotle, in the Phys., is also investigating the foundations of natural science, and he thinks that recognizing certain types of cause and certain theses about causality are essential to that project (e.g., what I refer to later as the NRC principle), causes turn out to be principles in more than one sense. Very often, as we shall see later, he will use ‘principle’ to refer to what, for his predecessors, plays a role equivalent to one or more of his causes, in a way which I think evokes both the conceptual and generative senses of starting points. That phusikê is supposed to be an Aristotelian science is clear from many references in the physical works, including the Physics itself, right from the start. The phrase ‘phusikê epistêmê’ itself is used elsewhere, including PA. I 1, 641a36, Met. VI 1, 1025b19, XI 4, 1061b28.

Reading (and Animating) Physics II 3  31 Timaeus present the study of nature, for whatever reason, as being of lesser scientific status than something like mathematics (29b1–​d3).12 The status of the science of nature is, in this context, reminiscent of modern debates about whether disciplines like psychology or economics should be considered sciences, and Aristotle is taking a strong position. The overall run of book II is as follows (all of the topics that follow are subject to controversy in ways that are in some cases quite consequential, but the synopsis should be acceptable for our purposes): Chapter 1 gives a general account of “nature” (phusis), including especially what it is to have a nature or to exist “by nature” (phusei), beginning with a distinction between things that are “by nature” and things that have other causes—​implying right from the start that nature is a cause (192b8). Things that exist by nature include animals, their parts, plants, and the “simple bodies” (i.e., Fire, Air, Water, and Earth): thus, organisms, their parts, and the most basic kinds of material object.13 Things are “in accordance with nature,” or “natural” (kata phusin) either if they themselves have natures or are “intrinsic” (kath’hauto) properties or features of things that have natures (the example is fire’s upward movement, 192b36).14 Something’s nature is “a source, that is, a cause of change and rest in that to which it belongs primarily, intrinsically and not co-​incidentally” (192b21–​23)—​“not co-​incidentally” serving to distinguish such things from things like patients who happen to be their own doctors, and artifacts. Aristotle then argues that while some thinkers tend to identify a thing’s nature with its underlying matter, form has a better claim to the title (though there is still an acceptable sense or context in which one can point to matter as a thing’s nature). Chapter 2 aims to distinguish the natural scientist from the mathematician, with the somewhat surprising implication (to modern ears) that this is not easy to do. (It may help to recall that the discipline is broadly conceived: Plato had included in mathematics not just arithmetic and plane geometry but also stereometry, harmonics, and an abstract science of moving bodies.15) The

12 He famously has him present it as a likely account (eikôs logos) or a likely myth (eikôs muthos). Commentators on these passages have disputed the meaning of this presentation; see, e.g., Johansen 2004; Burnyeat 2005. However we interpret it, the point and the difficulty remain: Plato thinks that the study of the natural world is subject to a kind of qualification which is not necessary for other, more properly scientific disciplines. 13 These are all also on the list of apparent substances given in Met. VII 2, 1028b9–​13, though the simple bodies are there referred to as the “natural bodies.” 14 On the term ‘kath’hauto’ and my use of ‘intrinsic’ as a placeholder-​translation of it, see p. 14 n. 21. 15 See Rep. VII, 522bff.; and Mueller 1991.

32  Causality and Causal Explanation in Aristotle basis of the distinction is ultimately that the mathematician studies things whose forms are separable in thought from change (kinêsis), while the natural scientist as such studies things which are not so separable, but are rather like “the snub,” which is essentially related to a certain type of matter, that is, noses (194a1–​7). This means that the natural scientist must understand the matter of natural things at least up to a point, as well as “that for the sake of which” natural changes unfold—​that is, final causes. Chapter 3 then presents the four causes and their attendant distinctions and details. Chapters 4–​6 discuss luck (hê tuchê) and chance (to automaton). The former is a species of the latter, but both are analyzed as applying to good results that do not regularly come about in a given way.16 They are to be discussed because their status is disputed: some early “physicists” unsuccessfully tried to eliminate them, saying that nothing is due to luck or chance, while others attributed implausibly many things to them, including eternal regularities such as celestial motions (195b36–​196a28). Aristotle’s position is in between: luck and chance are “co-​incidental” causes, in that there are situations in which good things result from the contingent confluence of otherwise distinct processes—​the things which cause these good results only happen to do so in the circumstances, and do not cause them intrinsically. However, since luck and chance are co-​incidental causes, and in fact strictly speaking do not cause anything, they are posterior to intrinsic causes—​ both conceptually and metaphysically, it would seem, since what are co-​ incidentally conjoined are in fact natural processes with their own intrinsic effects or results (198a1–​14). Chapter 7 returns to the basic four-​causal schema. Aristotle points out that each of the four can be an ultimate answer to a why-​question (198a14–​21). Here it is important to note that this is not a claim that all four causes must be cited for any given explanandum, but rather that any one of the causes may be given in such an answer. Thus, the student of nature needs to know all of them and refer inquiries back to them. Often, Aristotle continues, the form, first mover, and “that for the sake of which” all refer to the same thing, though the mover is only the same in species (198a24–​27). So we answer the question “Why?” by reference to a thing’s matter, form, and first or primary mover (198a31–​33). For cases of 16 Thus, they do not constitute the whole of what we might consider random or non-​regular occurrences. On these chapters see Lennox 1984; Judson 1991.

Reading (and Animating) Physics II 3  33 coming-​to-​be, we mostly refer to the mover, because this generally involves tracing sequences back to their starting points (198a33–​35). Thus (though there are four causes in general), there are two principles (archai) of natural change, one of which is natural in the sense of having an internal origin of change (i.e., the mover, such as the parent of a child), and one of which is “not natural” in the sense that it is a nature but does not itself have an internal origin of change.17 Aristotle then concludes that we must answer why-​questions in all these ways, that is, by explaining that something is a “necessary result” (appealing to efficient causes), that something is a necessary antecedent,18 that something is the essence of the thing, and that it is “better” for the relevant substance in each case to be a certain way (198b4–​9). (This needs emphasis because it is only here that Aristotle directly seems to state, in Phys. II, that we need to cite four things with respect to a single explanandum. But it is not in fact certain that this is the meaning of the passage, since it is supposed to follow from a discussion which makes no such statement or assumption. It would thus be odd if the idea that entities generally or paradigmatically require four causes for their explanation is in fact somehow at the heart of his conception of causes.) Chapter 8 then takes up the task of showing that nature is a cause that “acts for the sake of something” (198b10). He points out that some might argue that nature acts in such a way that certain results merely follow, and in particular that various good results (good for the substance in question, like having teeth suited for tearing and grinding) are, in fact, to be explained in terms of what c­ hapters 4–​6 defined as luck or chance (198b16–​32). He argues (somewhat notoriously) that this view is impossible.19 His conclusion is that there are final causes in “things that come to be and are by nature,” which should be read as the claim that such things have internal origins of change that are intrinsically for the sake of what they produce, rather than co-​incidentally related to them. This is affirmed at the end of the chapter: natural things are those that arrive at some end by continuous change from some internal 17 “But the principles that bring about change in a natural way are twofold, one of which is not [itself] natural (phusikê); for it does not have a principle of change in itself. Something is of this sort if it brings about change without itself being changed, just like what is completely unchanging and the first among all things, and the what-​it-​is, i.e., the shape; for this is the end, i.e., that for the sake of which” (198a35–​b4). 18 The reference is to material-​causal explanation, though the phrase is surprising. I return to it later, but see also Schofield 1991. 19 The reasoning is controversial in ways that are not relevant here. For a thorough discussion of this chapter and references, see Leunissen 2010, ch. 1.

34  Causality and Causal Explanation in Aristotle principle, but if we assert that these ends are only co-​incidentally related to the things that produce them, a consequence would be that the things that we call natural could in fact produce random results; in this case we would have in fact done away with nature and what exists by nature, the classes of phenomena laid down at the start of book II (199b13–​18).20 Finally, ­chapter 9 treats the question of the role of necessity in causal explanations of natural phenomena. “Contemporary” thinkers all treat necessity as applying very broadly, indeed as the only real cause in nature.21 We must ask, he says, whether natural things involve only hypothetical necessity or also involve “simple” (i.e., unqualified, haplôs) necessity. Contemporary thinkers take it that what happens in nature is a necessary result of the basic properties of things’ material components, such as elements like earth or fire in processes of generation. In fact, however, Aristotle claims, such properties are conditions, not causes, except in the sense of material causes (200a5–​7). This implies that natural things, at least those at issue in this passage, are not to be explained as the results of unqualified necessity. Rather, as with artifacts, the matter is hypothetically necessary: it must be a certain way if a certain result or activity is to take place. So the end necessitates the matter, not the other way around (200a11–​15). Necessity in nature in this sense is rather like necessity in mathematics, in that we start from a definition of something basic and derive necessary results about less basic things (e.g., we lay down definitions of things like ‘straight’ and then make deductions about triangles). In both cases, if we deny the consequent we must also deny the antecedent, though in natural science this means making inferences about earlier things on the basis of claims about later things. So necessity in nature is hypothetical—​“derivative” as I would read it—​rather than unqualified. The student of nature needs to cite both the end and the matter it necessitates, but especially the end, since it is the cause of the matter (200a15–​b4).22 Now, if we assume that part of the aim of Phys. II is to articulate a conception of natural science that justifies conceiving of it as a science—​an epistêmê in the full-​blooded sense of the term—​then we can see reasonably well how ­chapter 3 fits with the rest of it. The overall argument of book II would run as follows: We can have a science of nature because the phenomena we recognize as natural are in fact due to the natures of things, that is, to efficient causes which are internal to them and belong to them intrinsically, and

20 The example is of seeds producing any chance organism, but the point is general. 21 This point is made in the forward-​looking introduction to II 8, 198b11–​16. 22 On hypothetical necessity, see Stein 2016.

Reading (and Animating) Physics II 3  35 which are intrinsic causes of the kinds of regular change that we also consider natural. Though some thinkers would identify the nature of a thing with its matter, we can see that its form is a better candidate (II 1). But this, in turn, raises the question how natural science is different from mathematics, which on the whole studies the same things, and studies their forms as well. The difference is that the forms of natural things are not separable in the way that the forms studied by mathematics are separable, since they are not separable in that way from their matter (II 2). If we are to understand a thing’s nature as a certain kind of internal and intrinsic cause, then, we need to say more generally what kind of cause it is, what the difference is between intrinsic and co-​incidental (i.e., non-​intrinsic) causes, and how causal explanations of natural things ought to be given. Typically, things in fact have several intrinsic causes, and there are several distinctions we need to draw to make sure we capture them, in such a way that the intrinsic relationship between a natural efficient cause and its result is manifest (II 3). This is especially important given the confusion that arises about the role of luck and chance in producing good results; they do sometimes produce such results, but the way that happens is not characteristic of the way in which good results come about for natural things—​luck and chance are mere co-​incidental causes (II 4–​6). So we can see that causal explanations of natural things will appeal to these four types of intrinsic cause. Since good explanations must not only cite causes but be grounded in starting points (archai), we can also see that, in general, explanations of the comings-​to-​be of and changes in natural things will have two such starting points: the form of what comes to be and the natural thing which functions as an efficient cause, bringing it about that the form is present in its appropriate subject (II 7). Some would argue that the internal causes of natural things are nonetheless co-​incidentally related to them, and that they result from “unqualified” necessity. That is, they are merely the necessary results of the basic tendencies of more basic material constituents—​their causes may be internal, but they are not intrinsic to them. But this is not correct, and the kind of necessity that applies to the forms of natural things is in fact hypothetical, not unqualified necessity, which runs from the nature of the thing to its matter rather than the other way around (II 8–​9). So we can see what kind of cause things’ natures are, and how they render natural things scientifically intelligible in a strong sense, since the forms of natural things are causal principles of the sort described, and are intrinsically rather than co-​incidentally related both to what they produce and to what produces them.

36  Causality and Causal Explanation in Aristotle Thus, although Aristotle does not follow his common style of first laying out earlier views, common opinions, and puzzles that arise from them, followed by his own view, he nevertheless presents in Phys. II a coherent line of thought that answers to what he takes to be basic problems confronting a science of nature, including the contrasting or conflicting views of his predecessors. The four causes themselves are introduced, not as answering a question about how we can account for the existence of objects (whether natural or broadly construed), or with respect to questions about the nature of causality as such, but rather in the service of saying how we can account for the idea that a thing’s nature is an internal and intrinsic cause of it, its features, and the regular changes it produces and undergoes. We may suppose, then, that the reason Aristotle does not argue for or justify his distinctions is not that they are obvious or self-​evident, but that he is applying them to a specific topic and for a specific purpose. To see the philosophical motivations and conceptual commitments of the distinctions themselves, we need to look at the other contexts that underlie their application to nature.

2 Background 1 Critiques of the Predecessors

The second source of context, then, is Aristotle’s criticisms of his predecessors for their faulty conceptions of causes and causal explanation. These include their explanations of specific phenomena—​as we have just seen, Empedocles and other materialists are criticized for thinking that natural things and the good results that occur regularly with respect to them could be explained as being co-​incidentally related to their causes. However, it is also clear enough that Aristotle thinks his predecessors failed to recognize or satisfy more general desiderata concerning causal explanations, and taken together these criticisms are revealing. Some of Aristotle’s most significant and persistent criticisms are broadly epistemological, focusing on ways in which their principles are inadequate for natural scientific inquiry, while others are broadly metaphysical, focusing on features of the entities posited as causes or the relationships between them and what they are supposed to cause. As is often the case with ancient philosophers, metaphysical and epistemological considerations are not sharply separable.

2.1.  Epistemological and Scientific Critiques As is well-​known, Aristotle views the Eleatics as in essence denying the reality of change, and so rejecting a principle required for nature to be a genuine object of scientific study—​nature being, in general, the domain of things characterized by change. Phys. I contains Aristotle’s well-​known response: he asserts that the natural scientist does not need to argue for the existence or reality of change, but he also, evidently, takes himself to be obliged to respond to the Eleatic view in a reasonably full way and thinks that engaging with

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0003

38  Causality and Causal Explanation in Aristotle their arguments will help reveal the principles of the science he is seeking to lay down.1 More pointed is a concern that Aristotle emphasizes repeatedly in On Generation and Corruption (GC): in one way or another, his predecessors fail to preserve as genuine, and as genuinely distinct, the principal kinds of change Aristotle thinks must be recognized. That is, Aristotle thinks natural science must not only assume the reality of change but must also recognize the distinctness and irreducibility of four types of transformation (metabolê): generation/​destruction (genesis and phthora, i.e., substantial transformation), increase/​decrease (change in the category of quantity), alteration (change in the category of quality), and locomotion (change in the category of place).2 And, he argues, his predecessors have in various ways, both deliberately and accidentally, tended to reduce or eliminate one or more of these types of transformation and change in favor of the others. This sounds like a metaphysical dispute, and so it is, but, as I shall argue, Aristotle’s battery of arguments for preserving these distinctions are driven not so much by the thought that such reductions or eliminations are conceptually defective, but rather that they are in conflict with sound epistemological principles and the possibility of natural science. The early material monists, for example, are forced by their own principles to say that what appears to be generation is actually a kind of alteration.3 Pluralists such as Empedocles and Anaxagoras, by contrast, need to distinguish generation from alteration, since they regard generation as resulting from aggregation and disaggregation, but sometimes they do not realize this and say that generation is alteration anyway (I 1, 314a11–​16, b1–​12). They also accidentally eliminate alteration, evidently since, if they only recognize the essential properties of their principles, any change to those properties turns out actually to be destruction, not alteration. The problem, Aristotle thinks, is that the distinction between generation and alteration requires a distinction between substantial and non-​substantial transformation, which, he claims, requires distinguishing the matter of the changing entity as the subject which underlies change (I 1, 314b15–​26).4 1 Phys. I 2, 184b25–​a20; cf. Phys. VIII 3, 253b6, Met. VI 1, 1025b25–​26a6. At Phys. I 2, 185a12, he says: “But we must lay down that the things that are by nature, either all or some of them, are changing; and this is clear from induction.” 2 See especially Phys. V 1, 225b5–​9, Met. XII 1, 1069b9–​14. 3 GC I 1, 314a8–​11; Aristotle has in mind figures such as Thales and Anaximenes. 4 Cf. GC II 2, 329a35–​b2. Empedocles also has difficulty preserving the objectivity of growth (GC II 6, 333a35–​b3).

Background 1: Critiques of the Predecessors  39 Similarly, Aristotle argues that Plato, because of his focus on “dialectic” rather than the details of the natural world, posits as the principles of bodies geometrical entities of a sort that cannot actually yield a body capable of undergoing generation and alteration (GC I 2, 315b28–​16a4). Democritus does not fare any better at preserving generation, since aggregation and disaggregation cannot yield a change in which something goes from “being this to being that” as a whole. Aggregation and disaggregation make something susceptible to generation and destruction, but no more (GC I 2, 317a17–​31). Nor can we allow that these are the only ways in which bodies change, since that eliminates alteration (I 9, 327a14–​19). The atomists also wrongly eliminate genuine growth, which is not the same thing as mere accretion (prosthesis, I 9 327a23–​25). Further, they have difficulty saying how something gets acted upon at all, since they are committed to the view that atoms do not suffer action, though the alternative seems to require that they be self-​movers, and hence either divisible (i.e., into active and passive components) or subject to contrary properties (I 8, 325b36–​26b6). In general, the diagnosis of these various failures to preserve the distinct kinds of change is attributed to a failure to recognize matter in the right way.5 Why, though, are such reductions or eliminations unacceptable? Why cannot these thinkers reply that this is indeed their systematic goal: to show that we can explain all of the appearances in terms of a single basic kind of change, such as locomotion or aggregation/​disaggregation, such that all other changes are either illusory or supervenient upon it? Aristotle does indeed have metaphysical objections to certain forms of reductionism, but there is also an epistemological concern driving his insistence that we preserve not just the reality of change in general but of these four apparent forms of it specifically. Aristotle’s insistence here seems to be based not just on a generally conservative approach to appearances, but on a more pointed claim that these appearances about the types of transformation have a certain kind of authority, such that the reductionists cannot convincingly dismiss them. He seems to think, first, that the natures of and differences between these forms of change are evident in a way that makes them much harder to cast as mere appearance than the reductionists realize. He sometimes claims, for example, that it is evident to observation that sometimes things are generated or 5 See GC I 3–​5 for the full discussion responding to these problems and puzzles; the point that the key lies in getting the right account of matter is explicitly made at I 3, 318a9–​10.

40  Causality and Causal Explanation in Aristotle destroyed rather than merely changed, most prominently the “elements”—​ fire, air, water, and earth—​which we can observe, he thinks, transforming into one another.6 He also argues that some reductive attempts at explanation simply do not fit with what we can observe: the relevant theory does not explain the apparent change. He objects, for example, against those who would posit aggregation and disaggregation as the one basic kind of change, that we can observe that state changes such as that from liquid to solid simply do not occur the way their theory says they do, nor from other spatial changes to a thing’s parts. Rather, the whole thing changes from one state to the other, without there being any hidden discontinuities: But in general it is absurd for generation to occur in this way alone, when bodies are divided up. For this account eliminates alteration, but we see the same body at one time liquid and another time solid, while existing continuously, undergoing this not by division and aggregation, nor by turning and contact, as Democritus says—​for it has become solid from being liquid without having either been changed around in its order nor altered in its nature, nor are there now [i.e., at first] hard and solid things present, indivisible in mass; but rather it is all [first] uniformly liquid, and at another time hard and solid.7 (GC I 9, 327a14–​22)

Aristotle might strengthen this point about state changes by noting that these kinds of change are not only recognized by observation but also follow from his categorial distinctions, which, whatever their source, are not the result of simply assuming that our observations of change are accurate—​he needs to argue in Phys. V 2 that only some of the categories yield genuine change. That kind of convergence between theoretical and observational conclusions is something we should only give up in the face of powerful considerations. Further, eliminating any of these forms of change conflicts with what appears to be a kind of first principle he lays down at various points throughout the physical works, sometimes with subtle but important variations, which I will call the Non-​Random Change (NRC) principle. As he says in his derivation of the principles of change in Phys. I 5, “We must, then, 6 See especially DC III 7, 306a4, GC II 4, 331a7ff. At DC III 7, 305b1f., Aristotle claims that the followers of Empedocles and Democritus unwittingly turn the inter-​transformation of the elements into a mere appearance. 7 Reading “oude nun huparchei sklêra” at ln. 20–​21 with Rashed.

Background 1: Critiques of the Predecessors  41 first suppose that among all the things that are, nothing by nature either does whatever may chance, or is acted upon by whatever may chance, nor does just anything come to be out of just anything, unless we mean co-​incidentally” (188a32–​34). The importance of this principle for Aristotle is sometimes under-​appreciated. While it can sometimes look like an a priori thesis about change (e.g., as expressing the fact that, logically speaking, something can only become warm from having been another temperature), it also depends on what appear to be, for Aristotle, robust observations to the effect that in nature, there are regular patterns of transformations which things undergo, including generation and destruction, developmental changes, and agent–​ patient interactions, none of which simply follows from a commitment to the reality of change.8 We have already mentioned one appeal to the NRC principle as an observable fact of nature, at the end of Aristotle’s rejection of Empedoclean materialism in Phys. II 8: we simply do not see the kind of random patterns of generation that would be predicted on the basis of their account, and indeed someone who maintains a view that entails such randomness “destroys both nature and the things that are by nature” (199b14–​15). There are other passages as well in which this principle appears to be a robust piece of observational data that is difficult if not impossible to square with the thought that such regularities are only co-​incidentally related to their causes. In De Caelo IV 3, 310a23f., for example, the NRC principle is presented, not as something that follows from the very concept of change, but as pertaining to the metaphysical basis of various forms of natural change. After first making the point about changes themselves (i.e., their endpoints)—​and saying that it is something we observe (horômen, ln. 25), rather than, say, something that could not be otherwise—​he claims that this principle extends to agents of change as well: For since there are three kinds of change (one with respect to magnitude, one with respect to form, and one with respect to place), in each of these we see the transformation coming to be from contraries to contraries and intermediates, and that the transformation is not to whatever it may chance by virtue of whatever it may chance; but rather, just as what alters and what increases are different, so also what is capable of altering another and what is capable of increasing another [are different]. So we must suppose in the 8 Cf. Waterlow [Broadie] 1988, 6–​8; Bolton 1991, 23–​26.

42  Causality and Causal Explanation in Aristotle same way as well that what can bring about change and what can change with respect to place are not related as any chance thing [being changed] by virtue of any chance thing. (310a23–​31)

Thus, Aristotle connects the thought that a subject can only change to some F from having had some property in a restricted range, to the thought that only things of a given character can bring about each type of change, by acting on subjects of that sort.9 The NRC principle is not just a logical principle about change requiring contraries, then, but a manifest metaphysical principle that is at work in facts about the way changes occur. So someone attempting to reduce, say, alteration to a kind of change in place, must contend with our observational knowledge of regularities among the kinds of property that make subjects capable of being altered—​that is, the material causes of different sorts of change—​and the kinds of property that make agents capable of altering them. Perhaps Aristotle is being naive, a reductionist might respond, about our powers of perception and the degree to which natural phenomena might occur below their threshold, such that what appears to be generation or destruction is always in the end a kind of alteration, or vice versa, and about the strength of considerations of parsimony. (His own account of when a transformation constitutes generation or destruction in GC I 4 is, indeed, obscure in ways that invite such replies.10) Here Aristotle could reply that while such reduction is in principle possible for any given apparent generation, the reductionist is in a dialectically weak position if he wishes to maintain it universally. Insofar as atomism and materialist pluralism are meant to preserve the reality of the appearances of change in the face of Eleatic arguments that seek to undermine them, they do not have the luxury of simply dismissing some robust appearances about the kinds of change just because they do not fit their hypotheses about the physical basis of change.11 To reject such appearances about kinds of change while appealing to the authority of appearances about change itself, including many of the sort they attempt to reduce, would require much more powerful arguments besides considerations of parsimony. Thus, some of Aristotle’s predecessors’ views about causes, especially about matter, are problematic because they undercut certain basic principles

9 Cf. also Generation of Animals II 6, 743a21–​26.

10 See especially 319b8–​320a2, and Rashed’s 2005 commentary ad loc. 11 See, for example, the treatment of Leucippus in GC I 8, 325a23–​b5.

Background 1: Critiques of the Predecessors  43 and distinctions derived from experience that we need to assume if the natural world is to be an object of successful scientific inquiry. The reality and regularity of change must be preserved, as well as the manifest distinctions between the basic types into which change and transformation fall. At the very least, he might argue, if we are thoroughly deceived about the kinds of change, then we have little reason to think that a scientific study of nature is actually possible—​we are too poorly off at the start to think that we can get a stable grasp of changeable being, if we cannot prevent ourselves from thinking that certain kinds of change are real which are, in fact, not. Thus, underlying Aristotle’s claims about the metaphysical distinctions among the basic kinds of transformation is an epistemological critique of these thinkers for failing to accord due weight to our experience of and with natural regularities. There are further epistemological defects that Aristotle finds in the views of his predecessors, which reflect what seems to be a concern to strike the right balance between, on the one hand, the kind of explanatory power that comes with universality or ontological priority, and, on the other, the need to respect the peculiar and proximate features of the determinate or individual phenomena one is trying to understand. One must, he thinks, respect robust empirical data, and be persuaded by the right kind of arguments or reasons. At GC I 2, 316a5f., for example, Democritus is given special praise for having a healthy grasp of “agreed-​upon facts,” which results from an appropriate level of experience (‘apeiria’, lack of experience, is responsible for the corresponding defect), which in turn helps him to be persuaded by arguments appropriate to natural science (oikeiois kai phusikois logois, ln. 13). At the same time, as Met. I makes clear, causal knowledge is supposed to take us beyond experience, and from what is more knowable-​to-​us to what is more knowable-​by-​nature, where this movement is more or less understood as going away from what is particular and perceptible toward what is universal and intelligible.12 In general, this seems to involve discovering the “elements” of things, but as he points out in Met. I 9, there are risks involved in looking for the elements of everything (992b18–​993a10). We must 12 Craft (technê), for example, is glossed in terms of knowledge of universals at 981a15. The whole passage will be discussed further in § 9.2. Other passages support the basic idea that we begin with perception and particulars, and progress toward higher types of cognition and universals, including Topics VI 4, 141b3–​14 and APo. I 2, 72a1–​4: “I mean by ‘prior and more knowable to us, on the one hand, the things that are closer to perception, whereas [I mean by] ‘prior and more knowable without qualification’ the things that are farther away.”

44  Causality and Causal Explanation in Aristotle therefore recognize the difference between what can be decomposed into elements and what cannot. Further, if we posit universal explanatory elements, that is, one kind of cause out of which everything comes to be, we make it impossible to acquire knowledge of a new domain on the basis of prior knowledge. But all learning occurs this way, so unless we had innate knowledge of these principles, or could grasp the causes of everything all at once, including objects of sense perception that we have not observed, we would not be able to acquire knowledge (I 9, 992b24–​993a10).13 Finally, while one’s principles must, of course, not be too few, as we can see from considering early accounts of change, they must not be indefinitely or infinitely many either, since then nothing will be intelligible.14 Anaxagoras is accused of violating this condition, with this result (Phys. I 4, 187a26–​b13).

2.2.  Metaphysical Critiques At the root of many of these criticisms is a common theme: despite their differences, Plato, Empedocles, and the Atomists all posit a special class of entities as explanatorily basic, and they attempt to explain natural phenomena such as generation and change in terms of their relationships to those special entities—​rejecting, by implication at least, what cannot be so explained as having only secondary status, if not as mere appearance. Aristotle also claims that his predecessors’ attempts at causal explanation are metaphysically inadequate on their own terms, independently of the consequences of their assumptions for more basic requirements of natural science. Their approach to explanation, in the case of the materialists especially, is consistent with a kind of ontological reductionism that Aristotle also wishes to reject, but should be distinguished from it. It is not a foil for Aristotle’s criticisms about causes in virtue of a thesis about which objects are real, or are “beings in their own right.” Rather, it is a kind of explanatory reductionism, since it takes one kind of (metaphysical) explanatory relationship—​ whether participation in a Form or composition out of a basic material 13 This argument should be compared with the narrower argument leading up to the conclusion that we grasp principles of demonstration by means of perception, in APo. II 19, 99b20–​34. 14 Aristotle argues in Phys. I 6 that there must be more than two principles, because contraries alone do not suffice to account for change and generation (189a20–​b3). He argues that they cannot be infinitely many at Phys. I 6, 189a12–​12.

Background 1: Critiques of the Predecessors  45 stuff—​and supposes that any legitimate causal explanation must somehow appeal to it. More specifically, explanatory reductionism typically involves three commitments. One is a claim about relata: the reductionist holds that genuine causal explanation requires connecting an explanandum to entities in a special ontology (e.g., Platonic Forms, Empedoclean elements, atoms).15 A second is a claim about the connection: genuine causal explanation requires showing how an explanandum is grounded in or arises from a privileged metaphysical relationship. Typically we find both claims (e.g., participation in Platonic Forms, aggregation of Empedoclean elements by the action of Love and Strife), but in principle one can make the second claim without the first.16 A third claim is broadly epistemological: the special ontology and/​ or privileged relationship are not among the appearances, and so cannot be grasped by direct observation. Plato, Empedocles, and Democritus appear to embrace all three, on Aristotle's understanding of them, but Aristotle thinks that even views which only embrace some of them will suffer from the same problems.Thus, this kind of reductionism generally goes along with a thesis about what kinds of thing are ontologically fundamental, but the explanatory thesis is different, and at least in some cases separable. One common problem that results from this strategy is that the metaphysical “principles” that these thinkers take as basic are in some way insufficiently related to what they are supposed to explain, either because they are being attributed capabilities they do not have, or because they are too remote from the explananda in question to have the right bearing on their occurrence or existence. In GC II 9, for example, Aristotle argues that the materialists treated matter as not only necessary but somehow sufficient for generation and destruction, 15 The special ontology may be introduced for independent reasons (e.g., as fundamental beings we must recognize anyway), or for reasons having to do with explanation itself (e.g., as hypotheses without which we cannot explain what we think must be explained). 16 A clear example is Anaxagoras, who, as Aristotle reconstructs his thought, is not an ontological reductionist in the same vein as the Atomists, since he thinks that matter is infinitely divisible, but pursues the same sort of explanatory reductionism, in that he normally attempts to explain things in terms of the natures of their material components, only invoking “Mind” when this gives out (see especially Phys. I 4, 187a26–​188a18). Likewise, a Platonist need not dispute that perceptible entities are genuine beings in some robust sense, but still maintains that because Forms are “perfectly” what they are, e.g., Beautiful, only they can have explanatory power in relation to the properties of perceptibles. More generally, a special ontology may be either empirically motivated, as on modern views holding that whatever entities and relations are taken as basic in the physical sciences should be taken as basic for all causal explanation, or philosophically motivated, as on modern views according to which events, states of affairs, or processes ought to be taken as basic instead. (Plato would be clear ancient example of the latter, and, to the extent that Aristotle interprets him as motivated to preserve the phenomena, Democritus would be an ancient example of the former.)

46  Causality and Causal Explanation in Aristotle which, Aristotle thinks, attributes to matter a kind of efficacy it does not have:17 Further, by removing the formal cause, they also give to the [simple] bodies capacities, by which they generate, that are excessively tool-​like (organikas). For since, as they say, the hot separates things out by nature while the cold combines them, so also for each of the others, the one acts while the other is acted upon, and they say that out of these things and because of them, all the others come to be and are destroyed. But evidently fire itself is moved and is acted upon. Further, they treat the matter more or less just as if someone were to assign the cause of generation to the saw and to each of the tools; for it is necessary that something is divided when one saws, and is smoothed when one planes, and likewise for the others; thus however much fire may act and bring about change, still they do not go on to observe how it brings about change—​that it is weaker than the tools. (335b35–​336a14)

Part of the problem, then, is evidently that these thinkers, by ignoring formal causes—​that is, the formal natures of even basic types of matter like fire—​are forced to say that fire is essentially an active principle, rather than its heat (which would be more correct for Aristotle), even though it is manifest that fire is sometimes acted upon, and so could not be essentially active. Further, they fail to recognize that elements like fire are less determinate in their effects than tools, but they treat them as though they were (336a3–​12). That is, their specific effects in a given context are not due to or made necessary by their nature alone, but rather by the “use” to which their nature is put, or their particular mode of action in given circumstances, such that a certain effect is a necessary result.18 Failure to understand efficient causes is thus bound up with mistakes about matter and a failure to recognize formal causes.

17 Compare Met. I 3, 984a20f., which implicates a whole range of materialists; the target here is less clear: it may be especially Parmenidean accounts of nature. (See Joachim 1922 ad loc., who follows Alexander as reported by Philoponus; for a different account see Henry 2019, 92–​94, cf. Williams 1982, 185, and Kelsey 2003, 83.) 18 Aristotle argues that a related defect is manifest in the relatively unsophisticated materialist accounts of action and passion in terms of “like-​by-​unlike” (or in a minority of cases, like-​by-​like) principles. Once again, evidently, a failure to understand the relation between matter and the contraries it bears is at the root of the problem (GC I 7, 324a14–​24).

Background 1: Critiques of the Predecessors  47 The materialists are accused of a similar mistake in the context of animal generation, in attempting to explain sex differences by reference to heat and cold: Now there is some reason for thinking that heat and cold are the cause of male and female, and the secretion’s coming from the right or the left; for the right side of the body is hotter than the left, as is seed that has been concocted; and if it is it will be concentrated, and what is more concentrated is more fertile. But to speak this way is to touch upon the cause from very far away; we should instead approach as near as possible to the primary causes. (GA IV 1, 765a34–​b6)

Thus, however important matter may be as an explanatory principle, the early materialists, by making the basic elements the material causes of all natural things, are positing causes that are too remote from what they are alleged to cause, and attempting to make them do more explanatory work than they are capable of doing.19 Despite Plato’s commitment to transcendent Forms, Aristotle takes him to be a kind of explanatory reductionist as well, and open to a version of the same criticism.20 Famously, of course, Forms are too remote from their explananda even to work as essences, because a thing and its substance must not be separate, and because, more generally, if X is to contribute either to the knowledge or to the being of Y, X must be “in” Y.21 In this regard, the Platonists are making the same sort of mistake Aristotle attributes to the Pythagoreans themselves: But the causes and principles they state, as we said, are sufficient for mounting up even to the higher things, and harmonize even more [with them] than with accounts concerning nature. But they do not say anything

19 This principle that material causes must be cited at the appropriate level of specificity is clearly enunciated at PA. I 1, 640b17–​28: “the ancients who first philosophized about nature” appeal to the basic elements as explanatory principles, but their powers and properties by themselves are not sufficient for explaining natural beings such as humans and other animals; we must rather cite the formal and proximate material causes when considering the relevant explananda, such as the uniform (flesh, blood, bone) and non-​uniform parts. 20 Indeed, he sometimes treats atomist and Platonic treatments of the elements of material bodies as essentially the same kind of view for some purposes: see DC III 4, 303a8–​10, GC I 8, 325b25–​33. 21 See especially Met. I 9, 991a8–​b3. There has been much discussion, of course, about the nature of this criticism in particular, whether it is accurate, and what it implies about Plato’s metaphysics and epistemology, but the consequences Aristotle draws from it are clear enough.

48  Causality and Causal Explanation in Aristotle about how there will be change if limit and unlimited, and odd and even, are the only subjects, or how it is possible for there to be generation and destruction without change and transformation, or what the things that move about the heavens do. Further, even if one were to grant them that magnitude derives from these things, or if this were proven, still in what way will there be some bodies that are light while others have weight? For on the basis of those things they suppose and say, they do not say anything that concerns mathematical bodies rather than perceptible ones; which is why they have not said anything whatever about fire or earth or the other bodies of this sort, I suppose since they are not saying anything peculiar to perceptible things. (Met. I 8, 990a5–​18)

Thus, the Platonists, like the Pythagoreans, are accused of using causal principles which, even if they apply correctly to the mathematical domain, do not capture anything peculiar to the domain of perceptible, changing things. The commitment to Forms likewise, Aristotle thinks, either causes Plato and his followers to overestimate what Forms can explain, or to fail to appreciate the explanatory value of other things involved in generation and change. Indeed, he appears to criticize the Platonists for both thinking that Forms can function as efficient causes, and for failing to take seriously the burden of explaining how changes are initiated. In GC II 9, Aristotle argues that Socrates in the Phaedo must in fact think that Forms are not just formal causes but somehow sufficient for generation and destruction (335b7–​17).22 This, he thinks, would yield a metaphysically absurd and observationally wrong result, namely constant rather than intermittent generation, since Forms and participants always exist (335b18–​20). He also asserts that their thesis runs counter to the observable fact that it is doctors that produce health and knowers produce knowledge: “Further, for some things we observe that the cause is something else; for the doctor brings 22 Fine 1987, § 3 argues that Aristotle is not actually accusing Plato of having Forms act as efficient causes. However, he does attribute to Plato the view that the Forms are sufficient for generation and change (335b15–​16), and draws out an absurd consequence of supposing them to be efficient causes (i.e., they would constantly be generating). So he is at least accusing Plato of treating Forms as capable of performing all the work for which Aristotle thinks efficient causes must be explicitly introduced; moreover, the passage claims that everyone “dreams” of this cause though none actually name it (335b8), implying a vague grasp of the very thing that Aristotle has grasped clearly. Fine is right that in Met. I 7 and 9 Aristotle criticizes “those who believe in the Forms” for failing to provide an account of the source of change, but this is consistent with accusing them of thinking, implicitly or explicitly, that Forms can somehow do the work of efficient causes because they only had a vague grasp of the kind of explanatory tasks they needed to discharge, and this may be the point of the criticism of the Phaedo at Met. I 9, 991b3–​9.

Background 1: Critiques of the Predecessors  49 about health and the knower knowledge, while health itself and knowledge and the participants are [all along]; and it is the same for the other things that act in virtue of a capacity (dunamis)” (GC II 9, 335b20–​24). Unless Aristotle is simply arguing in bad faith, the point must be that doctors and knowers have greater explanatory value than the Platonist acknowledges or even can acknowledge—​after all, these are not esoteric observations, and the Platonist can readily acknowledge that there are certain sorts of individuals who are necessarily involved in the process by which a particular comes to participate in a given form. The more telling point would be instead that such individuals cannot have explanatory value according to the Platonists, since, at least on standard readings of the Phaedo, only what satisfies certain metaphysical and epistemological constraints can truly explain why something else has a share of F.23 (I shall return to this passage in §10.1.) In Met. I 9, some of these criticisms are repeated, along with a host of further objections to Forms, but then a new criticism argues not that the Platonists underappreciate the explanatory value of efficient or final causes in natural processes of generation, but rather that they cannot account for the origin of change at all, which in turn renders natural science impossible on their principles: And in general, though we are seeking wisdom concerning the cause of things that are manifest (phanerôn), in fact we [Platonists] have let that drop (for we say nothing about the cause from which there is a principle of change [i.e., the efficient cause]), but instead, thinking we are speaking about the substance of those things, we say that there are different substances, and we say empty things about the way the latter are the substances of the former; for “participation,” as we said earlier, is nothing. Nor, further, is this what we see (horômen) the cause to be in the sciences—​that because of which every mind and every nature acts, nor do the Forms get any grip on this cause, which we say is one of the principles, but instead, philosophy these days has become mathematics, though people say we must labor at it for the sake of other things. (992a24–​b1) And concerning change, if these things [sc. the Great and the Small] are to be change, it is clear that the Forms will be changed; but if not, where does

23 For the canonical properties related to Forms, see especially Phaedo 65d4–​66a8, 74a9–​75b2, 78c10–​79a5, 96a5–​102a1.

50  Causality and Causal Explanation in Aristotle change come from? The whole inquiry into nature has been eliminated.” (992b7–​9; cf. Phys. III 2, 201b20)

Here again, part of the problem is that transcendent Forms do not have a clear connection to what Aristotle thinks they are supposed to explain, and in fact if transformation and change—​or “being qua subject to change”—​are the primary explananda for natural science, then intrinsically changeless entities make for poor principles. This failure to provide a clear and appropriate relationship also includes the more local charge of naming symmetric and reflexive relationships such as likeness rather than an asymmetric and irreflexive one (991a19–​b1). Similarly, the “Great and Small,” the Platonists’ principles that Aristotle takes to be intended to function as a kind of underlying substratum similar to Aristotelian matter, are inadequate for that role.24 In Phys. I 9, Aristotle argues that the Platonists treat the Great and the Small in the same way as non-​being (hoi de to mê on to mega kai to mikron homoiôs, 192a7).25 In contrast, Aristotle wishes to claim that matter is a joint cause (sunaitia) of the things that come to be (hê men gar hupomenousa sunaitia têi morphêi tôn gignomenôn estin, 192a12), nearly and in a way substance (eggus kai ousian pôs, 192a6). Thus, Platonists have a view about “that out of which things come to be,” one which is general enough to apply both to numbers and corporeal entities, but is in fact (and perhaps thereby) so indeterminate that it cannot be distinguished from mere non-​being or privation.26 So whereas the materialists fail to recognize that matter as such is passive, the Platonists fail to recognize that matter, despite being passive, is nonetheless a determinate something, and so fail to assign it the right degree of explanatory power. So among the many different criticisms, ad hominem and otherwise, which Aristotle levels at the Platonic theory, one is that as a theory of causes 24 This is the candidate he focuses on here and in Met. I. Elsewhere, as in GC II 1, he criticizes the “Receptacle” of the Timaeus as similarly inadequate. 25 The criticism is related to the fact that the Great and Small are “indefinite” or indeterminate (apeira); cf. Phys. III 4, 203a15–​6; III 6, 206b28. On the Platonic Great and Small in general, see Ross’s 1924 note to Met. I 6, 987b20 (169–​71). For the Great and Small connected, rightly or wrongly, to the “material” principle of the Receptacle described in Timaeus 50b5–​52d1, see Phys. IV 2, 209b11–​16, and 209b33–​210a2. 26 Cf. Met I 9: “Further, one might suspect that the substance that underlies as matter is overly mathematical, and is more apt to be predicated and to be a differentia of substance and matter than to be matter; for example the Great and the Small are just the way the naturalists describe the rare and the dense, saying that they are the primary differentiae of the subject; for these are a sort of excess and defect.” (992b1–​7)

Background 1: Critiques of the Predecessors  51 it suffers from many of the same defects that affect materialist explanatory reductionism, and for similar reasons.27 Reductionists are also accused of failing to recognize the right array of phenomena as subject to causal explanation. The materialists in particular are accused of rejecting an important explanandum, namely the fact that things have and come to have goodness and beauty: “for it is doubtful that either fire or earth or anything else of this sort is likely to be the cause of the fact that some things have goodness and beauty and some things come to have them, nor did they think that it was; nor is it right to assign something of such magnitude to chance or luck” (I 3, 984b11–​15). These thinkers, that is, do not think that the beauty and goodness exhibited and acquired by natural things need an explanation in their own right. They think rather, on his reconstruction, that a combination of material natures is sufficient to explain all the features of natural beings that need independent explanations, and that chance can suffice to explain the rest.28 So the materialist reductionists are committed to causes that are too remote from what they are meant to explain, and indeed so remote that they deny that certain observable regularities even need explanation at all. On the other hand, a somewhat surprising problem that results from explanatory reductionism is that, while one’s causal principles may be defective by being too remote from their explananda, they may also fail to be broad enough in the right way. Aristotle evidently thinks that a mode of causal explanation that works for changing, perceptible things ought in fact to be extensible, with appropriate changes, to eternal entities, and vice versa. In Met. I 8 the early materialists are accused of having a concept of element that only extends to bodily entities, and so of failing to include the elements of incorporeals. This is because they focus only on what comes to be and passes 27 Cf. DC III 7, 306a5–​17, where Aristotle criticizes his predecessors for trying to bring everything back to certain predetermined opinions, and so failing to posit principles that are commensurate with and of the same order as the phenomena they are trying to explain: “they do not grasp the first principles correctly, but rather wish to lead all things back in relation to certain predetermined opinions. For one needs, presumably, perceptible [principles] for perceptible things, but eternal [principles] for eternal things; and likewise the principles of perishable things are perishable, and in general, things of the same kind as their subjects” (306a7–​11). 28 This criticism is, of course, relevant to, and in some ways a more general version of, the criticism of the Empedoclean-​type response to apparent natural teleology in Phys. II 8. On the kind of explanatory rejection at issue in relation to that chapter, see Meyer 1992. I agree with Meyer that the target is not reductionism in the (perhaps more common) sense of providing materialist explanations of the things that Aristotle thinks must be explained teleologically, and that the issue is rather whether such phenomena are genuine explananda in a specific sense. However, I do not agree that ontological eliminativism (794–​95, § 5) or candidates for substance are really the central issues either, so I prefer the label of ‘explanatory reductionism.’ For a contrasting view, see also Leunissen 2010, § 1.2.

52  Causality and Causal Explanation in Aristotle away (989b21–​24).29 Evidently, then, even though the study of nature and its causes involves studying what is subject to generation and change, this does not mean that our principles should be restricted, or wholly restricted, to such things. In a sense the point is simply that positing a basic kind of entity for causes will inevitably be too restrictive, limiting one to whatever such entities can directly explain. Nevertheless, the degree to which Aristotle thinks one’s principles ought to be extensible is quite demanding. Causal principles must be both appropriate to their subject matter, and so not overly broad, but also in some way, with certain extensions, applicable where appropriate across the whole range of what is intelligible. Finally, reductionists have a tendency, even when they recognize something as causally important, to fail to recognize the way in which it functions as a cause, because of their fixation on one mode of causation. Thus, all previous thinkers have failed to understand the way final causes explain things, Aristotle thinks, since to the extent that they recognize them at all they either make them function like efficient causes (materialists) or formal causes (Platonists): They do call that for the sake of which actions and transformations and changes occur a cause in a certain way, but they do not call it one in this way, that is, not in just the way it is in its nature to be a cause. For some, speaking about Mind or Love, posit these causes as good, but not that it is for the sake of these things that anything among the things that are either is or comes to be; rather, they speak as though the changes originate from them. And in the same way, even those who maintain that the One or Being is of such a nature say they are the cause of substance, but not that being or coming-​to-​ be is for their sake, so that it follows in a way that they both say and do not say that the good is a cause; for they say it is one [i.e., a cause] not unqualifiedly, but only co-​incidentally. (Met. I 7, 988b6–​16)

Thus, reductionists like Anaxagoras and Empedocles recognize goods such as reason and love, but treat them as efficient causes only, while Platonists treat the Good as a formal principle or cause of substance.30 Both fail to treat goods as causes for the sake of which anything is or comes to be.

29 This issue is related to the tenth aporia of Met. III, introduced at 996a2–​4 and discussed at 1000a5–​1001a3. 30 On Empedocles cf. Met. I 4, 985a4–​10.

Background 1: Critiques of the Predecessors  53 By treating one type of entity as causally basic, then, and taking seriously only the relationships in which they are directly implicated, Aristotle thinks his predecessors end up with principles that are too metaphysically remote from what they purport to explain and cannot be extended in the right ways; they also ignore or reject other important explananda that do not fit with their principles.

2.3.  Summary In sum, explanatory reductionism seems to lie at the heart of a great variety of mistakes, from a failure to treat empirical observations appropriately to inadequate attempts to stretch causal principles beyond their capabilities. Aristotle’s epistemological and metaphysical criticisms of his predecessors are varied, and one need not be an explanatory reductionist to be subject to all of them, but they do coalesce around some basic defects Aristotle finds with the strategy of requiring a special metaphysics for genuine explanation, and more generally with the kinds of appearance/​reality distinctions his predecessors draw. Positing a special metaphysics for causality has a tendency to lead us away from the phenomena we wish to explain, to turn those phenomena into something like mere appearances or derivative entities, and to do so for the sake of an explanatory payoff that is not as powerful as it seems. If we take Aristotle’s criticisms as indications of desiderata for a better account of causes, such an account must: (1) preserve the reality and intelligibility of transformation and change in general. (2) preserve and explain robust empirical data, including the distinctness of the main kinds of transformation and change, the regularity of various types of change, as well as the fact that, among living things, these regularly result in goodness and beauty or order. (3) respect and capture the difference between basic and non-​basic things (i.e., those that can be analyzed into elements and those that cannot). (4) use a finite but appropriate number of causal principles. (5) posit causes that are not too remote or indefinite in relation to what they cause. (6) use causal principles for nature that are extensible (where appropriate and with the right modifications) beyond the natural world, while still

54  Causality and Causal Explanation in Aristotle capturing what is peculiar to it and to the various important types of phenomena it contains, and which allow us to build from knowledge in one domain to knowledge in another. (7) capture not just what something’s causes are but the precise manner(s) in which they function as causes. This is a demanding list to be sure, and Aristotle has other criticisms of his predecessors, but these seem to be at the core of his views about what an account of causality must do in order to help ground a science of the natural world.

3 Background 2 Science and Dialectic

3.1.  Being “in Virtue of Oneself ” and in Other Ways The other main philosophical concerns to which a theory of causes must answer, and which lie in the background to Phys. II 3, have to do with general constraints on explanation and explanatory practice that are not directly related to understanding change or natural science. In this context, Aristotle’s interlocutors include especially Plato and the Academy, insofar as they are explicitly concerned with general features of explanation, definition, and dialectic. A primary focal point for these issues is the philosophical question that goes to the heart of the explanatory project Socrates launched, which connects the search for knowledge with definitions: how can we give an adequate definition of some object of inquiry, where adequacy includes explanatory power of a sort that yields genuine understanding of what we define? Plato takes up this challenge throughout his works, and we find Aristotle throughout his own corpus responding to Platonic claims about definition in different ways and in different contexts, especially as it relates to concepts such as genus, species, and differentia, and to ways of dividing up fundamental kinds. These concerns in turn intersect not only with Aristotle’s interest in division in the biological works, where he criticizes Platonic division and offers his own version instead (in PA I 2–​4), as well as the related points about division in Met. VII 10–​12, but with the logical works as well, especially the Topics, whose account of dialectical practice is structured in part by reference to four types of predicable: definition, proprium, genus, and accident.1 In these works, questions about how to give an explanatory definition of something become intertwined with even more basic questions about how 1 See especially Topics I 4 and 5, which include the differentia, sometimes treated as a fifth predicable, with the genus.

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0004

56  Causality and Causal Explanation in Aristotle to say anything about anything at all, with important results for Aristotle’s understanding of causes. The concepts of essence (paradigmatically captured in the phrase ‘to ti ên einai’) and definition (paradigmatically captured in somewhat broader and less technical expressions like ‘logos’, ‘ti esti’, ‘horos’, ‘horismos’) are, of course, important.2 But another shared notion, related but perhaps more basic, is a rough but important distinction, or series of distinctions, between what we may call here intrinsicality and extrinsicality.3 (The distinction is developed in different ways in different contexts, and is at times so hazy that these must be taken as placeholder terms, without commitment to any specific understanding of either.) In Plato we find one side of the distinction applied especially to Forms, which are specified as “the F itself,” or as being “themselves by themselves” (auta kath’hauta), terms which are generally glossed by Plato and his commentators in terms of independence, separateness, non-​relativity, stability, perfection, purity, not admitting “co-​presence of opposites,” and so on. They are contrasted with things that lack that special independence or perfection.4 The nature and possible evolution of this distinction is disputed, but we can see several ways in which Plato is concerned to distinguish what pertains to something “all by itself,” or in its own right, and thus without qualification, as opposed to what pertains to something in relation to other things, or in some other qualified way. On the whole, for Plato, if something is not what it is in virtue of itself, then, at least in some contexts, it appears to follow that it is not maximally intelligible.5 2 They are also interconnected, and Aristotle’s use of the latter phrases is complex. Canonically, though, a ‘horos’ is an account (logos) indicating the essence (to ti ên einai) of something (I 5, 101b38–​9). 3 While ‘extrinsic’ is not, for the reasons stated earlier (p. 14 n. 21), my preferred translation for ‘kata sumbebêkos’ (co-​incidental), it will do well enough for the family of contrasts with ‘kath’hauto’ of which co-​incidental is one member. 4 For such language applied to Forms, see Phaedo 66a2, 75c10–​d1, 78c10–​d7, 102d6; Parmenides 129d7–​8, 133a9; Timaeus 51c1. This language is, of course, related to the notorious problem of whether Plato “separated” the Forms and what that entails; for a recent discussion, see Silverman 2002. The difference is also related to a general distinction Plato seems to draw between things that are “said themselves by themselves” (auta kath’hauta) and things that are “said in relation to something else” (pros ti). See Soph. 255c12–​13: “But I suppose you agree that among the things that are, some are said themselves by themselves, while others are always said in relation to other things.” (“All’oimai se sugchôrein tôn ontôn ta men auta kath’auta, ta de pros alla aei legesthai.”) This distinction in turn may be the root of a fundamental division among primary things between “absolutes” (kath’heauta) and “relatives” (pros ti). See Diogenes Laertius III.108–​9 and Dancy 1999. 5 This is the implication of the famous argument about the lovers of sights and sounds in Republic V, 478e7–​480a10.

Background 2: Science and Dialectic  57 A related point specific to causality, which Plato develops in the Phaedo, involves the requirement of a necessary connection between causes and effects. In particular, one of Socrates’s motivations for appealing to Forms as causes is his puzzlement at the way the kinds of cause described in “natural history” (peri phuseôs historian, 96a8) can sometimes bring about contrary effects, or certain effects can be ascribed to contrary causes. Forms are not like that, since they are what they are in such a way as to exclude contraries: Tallness itself and “the tallness in us” cause only tallness, and neither admit of nor cause shortness (102d5–​103a2). So the way in which Forms are what they are intrinsically, without qualification, is related to their capacity to function as causes in the demanding way Socrates requires. Like Plato, Aristotle often contrasts things that are or hold of something “in themselves” (kath’hauto) or without qualification (haplôs), with things that do not. The contrasts vary and are not always clear, but some primary oppositions are to what is not essential, what is contingent, what is related to something else, and what “is” or comes to be in a qualified way (e.g., coming-​ to-​be some F, ti, as opposed to coming-​to-​be full-​stop).6 Once again, the impression is of a rough but varying distinction between what something is all by itself and what depends on other things or is somehow extrinsic or secondary. This concern is reflected in the distinctions Aristotle draws between different types of predication. Some predicates hold of their subjects intrinsically; others do not. The former are closely connected with the notion of a thing’s essence: in general they are either a term in the essence, a higher-​level genus-​term, or a necessary property that flows directly from the essence, that is, so-​called per se accidents or propria, since they apply to the subject “in virtue of itself.” The latter are generally distinct from a thing’s essence (but again, as we will see, the connections are complicated).7

6 For “being” co-​incidentally vs. intrinsically, see Met. V 7 1017a7–​30; for the canonical definition of co-​incident, see Top. I 5, 102b4–​26; for ‘co-​incident’ as ambiguous between contingent and necessary-​but-​not-​essential properties, see Met V 30, 1025a14–​34. For intrinsicality contrasted with relativity, see, e.g., Top. V 5, 134a18–​25, APo. I 22, 83b18–​24, DA I 3, 406a4–​8. Especially interesting for our purposes is APo. I 24, 85a23–​25: “we understand each thing better, whenever we know it in itself (kath’hauto) than when we know it with respect to something else (kat’allo).” (The statement is a premise in an argument Aristotle rejects, but the premise itself is blameless in context, and should be compared with APo. I 2, 71b9–​12.) For unqualified vs. qualified coming-​to-​be, see Phys. I 7, 190a31f. 7 Besides the contexts and passages noted earlier, see also, as related to definition, Top. I 15, 106a1–​ 8, and Phys. IV 2, 209a31: “something can be said of a subject either, on the one hand, intrinsically (kath’hauto), or, on the other, in virtue of something else (kat’allo).”

58  Causality and Causal Explanation in Aristotle In APo. I 4 73a34–​b16, Aristotle distinguishes four notions of being something intrinsically (kath’hauto), three of which apply to ways in which something is predicated of or “holds of ” a subject, and one of which does not. In Aristotle’s order of presentation, which is the standard way of referring to them: A holds of B intrinsically if (1) A is in the essence of B; or (2) B is in the essence of A (e.g., ‘straight’ holds of ‘line’ intrinsically because the definition of ‘straight’ appeals to ‘line’).8 (3) Another sense refers to things that do not hold of a subject at all, but rather indicate substance or “some this” (tode ti, 73b7); these things exist in their own right (kath’hauto). Finally, somewhat obscurely, Aristotle says that (4) A holds of B intrinsically if B is A “because of itself ” (di’hauto). Aristotle’s example is awkward, and it seems to be that ‘died’ holds of ‘what is sacrificed’ intrinsically, since ‘died’ holds of what is sacrificed because of its being something sacrificed. He does not develop the point further, but it is worth noting that some kind of causal connection is marked as constituting an intrinsic relationship between subject and predicate.9 Two further applications of this distinction are especially important for Aristotle’s discussions of causes and essence-​specifying definitions: In APo. II 9, 93b21, Aristotle draws a distinction between things that have something else as their cause, and things that do not.10 He does not directly state that the latter things have themselves as causes, but it is implied, since in an earlier passage he notes that a cause will be either “the same or other” than what it causes (II 8, 93a5–​6).11 The distinction is, in any case, immediately related to a difference in the way we can specify what something is: something that lacks an external cause and is a “principle” (archê) must be defined the way mathematicians lay down definitions of things like the unit, whereas things that have other causes can have their definitions revealed through a demonstrative syllogism (93b21–​28). The details are somewhat obscure and controversial (some of these difficulties will be discussed in the next part), but the basic idea is that there is a distinction between ways in which things are defined which mirrors a difference in their causes.

8 Following Gill 2005, § 5.1, I will refer to these as “special” properties. 9 Aristotle does not here use the word ‘cause’, but rather a causal locution. The passage also mixes linguistic and non-​linguistic terms (e.g. “said of,” “holds of ”) in a familiar Aristotelian way. For further details see the commentaries of Ross 1949 and Barnes 1994 (ad loc.). 10 “Of some things there is something different that is the cause, while of other things there is not.” This point is connected to epistemological questions, and whether our knowledge of something is direct or indirect: cf. the passage 85a23–​5 cited earlier. 11 On this passage, see Deslauriers 2007, 45ff.

Background 2: Science and Dialectic  59 Another, related distinction Aristotle draws is between things that are necessary “in virtue of something else,” and things that are necessary in virtue of themselves, the latter of which are unqualifiedly necessary and are the causes of the former things’ being necessary: “Now of some things there is something else that is the cause of their being necessary, while of others there is not, but rather other things are of necessity because of them. Thus what is necessary in the primary and strict sense is what is unqualifiedly necessary” (Met. V 5, 1015b9–​12). Once again, a causally important concept is said to apply strictly when it applies to something all by itself, as distinct from when it applies in virtue of something else. These passages are worth connecting to a chapter in the “Lexicon” of Met. V which is usually passed over without comment, ­chapter 18, on “in virtue of ” (‘kath’ho’). No doubt it is ignored in part because ‘kath’ho’ by itself is not a technical term that occupies a large role elsewhere in Aristotle’s writings, and because it does not appear to state anything too difficult or controversial, but it is of interest here. First, even though ‘kath’ho’ is not clearly a technical term on its own, it evidently does relate to the cluster of other technical terms such as ‘kath’hauto’, ‘kat’allo’ (“with respect to another”), ‘kath’heteron’ (“with respect to something different”), and ‘kata sumbebêkos’ (“co-​incidentally”). Second, Aristotle introduces in this chapter a distinction between primary and secondary ways of being kath’ho, and directly connects it to the plurality of causes: ‘That in virtue of which’ is said in many ways; one way is the form and substance of each thing (pragmatos), for example, that in virtue of which someone is good, is the good itself; another way is that primary thing in which something comes to be by nature, for example color in a surface. Now what is said to be “that in virtue of which” in the primary way is the form, and in a secondary way the matter of each thing, i.e. the primary subject for each thing. And in general, “that in virtue of which” applies in as many ways as “cause”; for one says, “in virtue of what has he come?” or “for the sake of what” has he come, and “in virtue of what has he reasoned badly or reasoned correctly?”, or “what is the cause of his correct inference or mistaken inference?” (1022a14–​22)

Thus, the primary sense of ‘in virtue of ’ indicates form or definition, the secondary sense indicates matter, and more generally, the other kinds of cause. This suggests, insofar as the kath’ho prepositional schema has an explanatory

60  Causality and Causal Explanation in Aristotle content, that Aristotle recognizes primary and secondary modes of causation, such that formal causes are somehow primary. In general, then, we can say that discussions of causation and explanation in Plato and Aristotle share a rough distinction between what holds of something primarily or unqualifiedly or in its own right, and what holds of it some other way: qualifiedly, relationally, or in virtue of something else. The differences among these ways of glossing the distinction are, of course, far from trivial.

3.2.  Physics II 2 and the Autonomy of Natural Science These questions about definition and essence are part of the background to the “departmental” questions Aristotle raises in Phys. II 2. As we have already seen, II 1 introduces the scientific study of nature and determines that form is the better candidate for specifying the “nature” of a natural thing. This raises a question for Aristotle which might seem puzzling: Next we must consider what differentiates the mathematician from the natural scientist (for natural bodies have both planes and solids, as well as lengths and points, things that the mathematician examines); further, [we must consider] whether astronomy is different from or a part of natural science; for if it pertains to the natural scientist to know what the sun or the moon is, but not to know any of the attributes that belong to them intrinsically, this would be absurd, especially since those who speak about nature evidently speak about the shape of the moon and the sun, and indeed whether the earth and the universe are spherical or not. (193b22–​30)12

That is, we must say why natural science is not simply a part of mathematics, and whether or not it includes astronomy. Though somewhat puzzling by themselves, when considered against an Academic background, these questions naturally arise from Aristotle’s claims about nature in Phys. II 1. After all, mathematics studies forms as well, and for Plato “mathematics” includes not just geometry and arithmetic but also stereometry, kinematics, harmonics, and astronomy (the latter two of which Aristotle himself includes along with optics as among “the more natural-​scientific of the mathematical

12 On this chapter see especially Lennox 2008 and 2015.

Background 2: Science and Dialectic  61 sciences” [ta phusikôtera tôn mathêmatôn, 194a7–​8]). It is not unreasonable to wonder, then, whether the discipline that studies natural things should not be simply included within mathematics (if it is genuinely scientific) or excluded from science, if it studies forms in some other way. To put the point another way, one might argue that if we are to study nature scientifically, then the conceptual tools of mathematics are sufficient, especially since mathematics already arguably includes the study of moving bodies, and nature is pre-​theoretically identified as the domain of beings that are subject to change. There is thus no need for an independent science of nature. There are, further, good reasons for which both Plato, and Aristotle in the APo., take mathematics as the model and star example of a science. If a good explanation makes it clear why the explanandum must hold, then formal demonstrations from universal principles to universal truths seem to accomplish this precisely because they appeal to necessary, universal, formal features of elements in their domain. If we can also study moving bodies with the same tools, why think that we would have anything to gain by doing something different? If we can already use our most precise and illuminating tools for a given domain, why insist on using duller ones? (This worry is, in fact, an ancient analogue of the worry that a precise, universal science like physics provides such compelling explanations that other disciplines can at best approximate or imitate it, and may in fact have to settle for offering descriptions rather than explanations.) The challenge thus appears to rest on principles that Aristotle largely accepts: (1) mathematics is a paradigm of scientific understanding; (2) mathematics studies the formal aspects of things, which are what their definitions capture; but (3) the natural scientist also studies the forms of natural things, captured in essence-​specifying definitions. So there are strong prima facie reasons to think that to the extent nature is scientifically intelligible, it is so with, and only with, the tools and methods of the mathematical, that is, formal, sciences. The difference, for Aristotle, turns on a peculiar feature of the definitions of natural things, namely that in some sense they include matter and change: they are defined like “snub,” not like “concave” (194a3–​ 7).13 So (2) wrongly assimilates definitions with formal aspects alone. Whatever the ultimate import and strength of this response, the Platonist challenge is strong, especially since Aristotle seems to accept so much of

13 The import of this feature has been the subject of much debate; see § 6.2 and the references there.

62  Causality and Causal Explanation in Aristotle it, and since his response opens up legitimate worries about whether natural things really are wholly intelligible, on his principles.14 Because of this commitment, and for related reasons having to do with the extent to which hylomorphic substances are to be identified with their form, as well as the precise relationship of form to matter in such substances, Aristotle and his commentators have a notoriously difficult time clarifying just how substance is scientifically intelligible. Once again, then, a heavy burden is placed on the concept of matter to justify both the possibility of natural science and its autonomy from the various kinds of formal study collectively considered under the heading of “mathematics.”

3.3.  Posterior Analytics II 11 and the Simple Schema of Causes Finally, we should include in the conceptual background concerning questions about definition, essence, and predication the somewhat different and notoriously troublesome four-​causal schema that Aristotle presents in APo. II 11 and his reflections on it.15 By “background” in this context, I do not mean that it is necessarily historically prior, though I suspect that it is, but rather that it is conceptually simpler and more basic, such that it is preferable to view the discussion in the Physics as extending this simpler schema to a different and more difficult task. The simpler schema is presented in the context of Aristotle’s theory of scientific demonstration as follows: Since we think we understand whenever we know the cause, and there are four causes—​one being “what it is to be,” one being “what things being the case, necessarily this is,” another being “what first brought about the change,” and fourth, “for the sake of what,”—​all of these are proven through the middle term. For the “that which, being the case, necessarily this is,” cannot be proven when a single premise is assumed, but rather at least two; 14 After all, it has proven difficult for commentators to reconcile Aristotle’s optimism about the intelligibility of nature with his view that matter as such is in some sense not fully intelligible. The issue arises prominently, for example, in the discussion of matter’s claim to be substance in view of its being the ultimate subject; see Met. VII 3, 1029a20–​33, and VII 10, 1036a9. 15 My claims about the ways in which this schema is different and should be taken as background for the one in the Physics will be more controversial than the preceding. For a fuller treatment of some of them, see Stein 2021.

Background 2: Science and Dialectic  63 and this is the case, whenever they have one middle term. So, when this one thing is assumed, it is necessary for the conclusion to be the case. It is also clear in this way: Why is the [angle] in the semi-​circle right? What being the case, is it right? Let what is right be A, half of two rights B, the [angle] in the semi-​circle C. The cause of A, right, belonging to C, the [angle] in the semi-​ circle, is B. For this is equal to A, while C is [equal] to B; for it is half of two rights. So, since B is half of two rights, A belongs to C (and this is the angle in the semi-​circle’s being right). (II 11, 94a20–​34)

Causality, as this passage emphasizes, is relevant to scientific demonstration since the middle term of a demonstrative syllogism is supposed to indicate the cause in virtue of which the major term holds of the minor term. Thus, paradigmatically, to use a different example related to triangles: (1) All triangles (B) have angles that sum to two right angles (A). (2) Isosceles triangles (C) are triangles (B). (3) So isosceles triangles (C) have angles that sum to two right angles (A). (Or, in Aristotle’s idiom, “A belongs to C” because of the middle term, B.)16 Commentators have found the schema and its accompanying explanation in this passage puzzling for a variety of reasons, and it is disputed whether and to what extent it is the same as or coheres with the schema in Phys. II 3 and elsewhere. There are a number of important differences between the two, ranging from subtle to stark. One subtle difference concerns the phrasing by which the causes are presented, which bears the marks of dialectic. Where the Physics refers to the efficient and final causes simply as “the primary principle from which the transformation or rest originates” (hothen hê archê tês metabolês hê prôtê ê tês êremêseôs, 194b29–​30), and “the end, and this is that for the sake of which” (to telos, touto d’estin to hou heneka, 194b32–​3)—​that is, referring to the causes themselves—​this passage adds definite articles which makes it sound like we are discussing either ways of citing or ways of asking about causes. They are, literally translated, “the what first brought about the change” (“hê ti prôton ekinêse”) and “the for the sake of what” (“to tinos heneka”), respectively. Thus, they appear to refer to a cause by way of a pattern or schema

16 See canonically APo. II 2, 90a7–​15, and APo. II 11.

64  Causality and Causal Explanation in Aristotle of explanation or question-​answering, rather than by reference to the entity cited in such a schema, and I think this is borne out in various ways by what follows in the text. A further difference concerns the approach to explananda. In Phys. II 3 Aristotle presents causes of various things or properties—​statues, bowls, octaves, children, health (all in 194b25–​33)—​and states the aim of explaining generation, destruction, and every type of natural change in terms of their causes. The APo. schema is broader still. First, there is no explicit scope given, and Aristotle’s examples range widely, including especially the geometrical demonstration of the fact that an angle inscribed in a semi-​ circle will be a right angle (94a28–​34). Further, the APo. passage does not describe explanations of things or changes as such, but rather predicational ties—​“facts” of the form “A belongs to (i.e., is predicated of) B.” This is pretty much demanded by the syllogistic treatment that integrates causes into demonstrations as middle terms. It also fits, however, with the closely related dialectical practice of setting “problems” (problêmata) of the form “Is A B?”—​for example, “Is the good knowledge?”—​and seeking to defend or attack positive or negative answers to such questions.17 Thus, this schema gives us ways of answering “problems” of the form “Is A B?” by finding causes in virtue of which A is B, or by showing the contradictory. Or more precisely, since in the APo. Aristotle separates factual “whether A is B” questions from explanatory “Why A is B” questions, this schema describes ways of accomplishing the latter, more scientifically advanced task.18 Evidently the schema can thus in principle cover predicational ties in any sort of context, mathematical or otherwise, whose subjects need not be substances or substance-​like; whereas the Phys. focuses on things, and more narrowly on natural phenomena such as substances and the transformations they undergo. Another difference concerns the kind of causal pluralism at issue. In Phys. II 3 we are told that there are many intrinsic (kath’hauto) causes of the same thing; these are not rival causes, but somehow all contribute something different to the overall causal explanation (195a26). Phys. II 7 also implies that 17 Cf. Topics I 4, 101b15–​36, I 11, 104b1–​5. Aristotle refers to “problems” in the APo. in several relevant places and connects them to his project of describing scientific demonstration II 14; he does not mention problems in Phys. II (though Hardie and Gaye in the Revised Oxford Translation misleadingly insert the term in II 3 and II 7), and he indeed mentions questions that are not of the “Is A B?” form, such as “what comes to be after what, and what first acted or was acted upon?” (198a34–​5). 18 He distinguishes the questions and the stages of inquiry they represent in APo. II 1–​2. I discuss these chapters in § 9.4.

Background 2: Science and Dialectic  65 the natural scientist ought to give multiple causes for any given explanandum, even if there are cases of overlap or co-​reference.19 There is no such parallel claim in the APo. passage, which only states that some things can be for the sake of something and also “by necessity.”20 In principle, in fact, it seems that the default position in this demonstrative context would be that there is only one intrinsic cause of a predicational tie. On the face of it, whereas the Physics is naturally read as presenting four kinds of intrinsic cause which are normally mutually compatible and perhaps (at least in some cases) jointly required for a proper causal explanation—​indeed, this is often treated as its core claim—​the APo. presents us instead with four co-​ordinate and independent (even if not exclusive) types of cause by which a given predicational tie may be demonstrated to hold, any one of which looks sufficient on its own for scientific understanding of the explanandum. The starkest difference between the two schemas, however, and the one that has caused the most controversy, is that the APo. schema does not refer to matter in any of its standard guises—​namely, as being “that out of which something comes to be,” or “that in virtue of which something is capable of being or not being” (e.g., capable of having or coming to have one of a pair of contrary properties).21 The phrase “what things being the case, necessarily this is the case,” which occupies the only position in which we could expect to find matter, has puzzled commentators both in its own right and with respect to the geometrical demonstration about the inscribed angle that Aristotle sketches to illustrate it. Since everywhere else Aristotle refers to four causes that include matter, but not “what things being the case, necessarily this is,” many commentators conclude that he must here be referring to matter in some oblique way.22 Others have argued that the text as presented simply cannot be stretched to apply to matter as Aristotle conceives it in the physical and metaphysical works, so we should not try to force the text to say something that it does not; and since “matter” does not appear anywhere else in the Organon, perhaps its introduction in Physics I–​II represents a shift

19 These passages and issues that arise from them are discussed later, especially chs. 5 and 7. 20 APo. II 11, 94b27–​28. 21 These are both canonical statements about matter, though the first is perhaps better known, given its presence in the even more canonical Phys. II 3. See Met. VII 7, 1032a20, VII 15, 1039b29–​30, and GC II 9, 335a32 for the latter characterization, as well as VIII 1, 1042a27–​28, IX 8, 1050a15 and XII 5, 1071a10–​11. 22 This is probably the standard view; see especially Barnes 1994, 226–​27, for a response to the main worries about the passage raised by Ross 1949, 638–​41.

66  Causality and Causal Explanation in Aristotle in Aristotle’s views or at least a sharp change in context.23 Perhaps Aristotle even “discovered” matter in between writing the APo. and the Physics. In my view this passage refers, not to the matter of a hylomorphic compound, but rather to a mode of explanation by reference to antecedently given facts, which in the context of a demonstrative science amounts to more general facts, including facts about the genus of the subject in question.24 The star example of this kind of explanation, used in fact throughout the APo., is explaining the fact that isosceles triangles follow the 2R rule, which Aristotle insists we must do by reference to the general fact that all triangles do, rather than by reference to anything peculiar to isosceles triangles. Here, since his point is to show that all types of cause need two premises in a demonstrative syllogism in order to be proven, he gives a more involved example of showing why any angle inscribed in a semi-​circle will be a right angle (94a23–​27). Though this is not material causality, there is a connection to matter insofar as Aristotle thinks the genus of a species is analogous to the matter of a hylomorphic compound.25 Thus, one way in which something may be shown to hold of a given subject for general reasons is that it holds of its genus as such, and of it, therefore, derivatively.26 We can see, then, how material causation could occupy the same place in a four-​causal schema when we shift to a natural-​scientific context, and how material-​causal explanation might exemplify the same explanatory pattern. Nevertheless, the causal relationship described in APo. II 11 is not material causation. In light of this clarification, the fact that explananda in the APo. are true predications is even more significant, since we can also assume that if we are explaining why some predicate holds of a given subject, we are not explaining why a subject of predication exists—​the existence of the subject, 23 Ross 1949. Graham 1987 argues for what I take to be an extreme view, namely that the APo. presents an “incommensurable” system with which the Physics is a radical break. 24 I defend this interpretation in Stein 2021; cf. also GC I 7, 324b6–​9: “For we say that the same matter, so to speak, is equally either of two opposites, being as it were a genus, and that what is capable of being hot, when what is capable of heating something is present and approaches, necessarily is heated.” 25 The nature of this analogy is also puzzling, but it may connect this passage to various aspects of Aristotle’s engagement (positive and critical) with the Academy; reflections on the relation between species and genus are of great concern in the early Topics, for example. 26 Besides the reasons given, since matter is essential to all the kinds of change described in the Physics, but matter is essentially a subject which admits of contrary properties, it is difficult to see how matter can actually play the role of a middle term in explaining changes, even if it could explain the causal propensities to change of higher-​level composites. That is, one can make sense of a demonstration that statues tend to sink because they are earthy, and all earthy things tend to proceed downward, but one cannot demonstrate that statues must sink because they are made of bodies which have the capacity to move downward.

Background 2: Science and Dialectic  67 that is, what the minor term refers to, is being assumed, not proven. The idea that something’s existence might itself be construed as exhibiting the same sort of structure, that is, form inhering in matter, is peculiar to the context of hylomorphism; and if there is no reference to this concept of matter here or anywhere else in the Analytics, or indeed the rest of the Organon, we should not assume any such relationship is being taken as a possible explanandum in the APo. At the very least, we should notice how smoothly this schema works when we restrict it to explaining the presence of properties in a subject rather than the existence or generation of a natural being: a person is capable of laughter because she is essentially human (i.e., the property follows from the human essence); a helmet is heavy because of its matter; a house is gabled because of the builder’s decision; a house is roofed for the sake of protection. It is far less obvious, and has been a source ongoing controversy, how Aristotelian demonstration can or should be applied to other types of epistemic or explanatory task, especially natural science in a hylomorphic context, whether in explaining the existence of certain individuals or kinds, their essences, or their primary features.27 One apparent difficulty is that if natural beings are form-​matter compounds, and the inherence of form in matter is analogous to a predication relation, then insofar as the existence of such compounds is an explanandum, the form seems analogous to the major term in a demonstrative syllogism; but on the APo. schema one expects the cause to occupy the role of a middle term, not the major, and in the Met. Aristotle names a thing’s form as the cause of the matter’s being something (Met. VII 17, 1041b7–​9).28 Further, where the Phys. II schema is very naturally construed as stating or implying that multiple modes of causality are required for a single explanandum, this is a very unnatural reading of the APo. schema. 27 For some influential pessimistic assessments, see Lloyd 1991 and 1996. More optimistic responses can be found in Gotthelf 1987b and 1997, Detel 1997, and Lennox 1994 and 2001; for an intermediate position, see Charles 2000. For a more recent, careful, but again pessimistic account of the difficulties, see Ferejohn 2013. 28 This is not to say that the schema cannot apply to hylomorphic explanation or other tasks, and I will return to the issue later. Aristotle himself uses it to show, in APo. II 8–​10, that certain kinds of definable entity can have their definitions revealed, though not proven, by a demonstration; for a full treatment, see Goldin 1999. For a clear treatment of the difficulties and strategies for applying the demonstrative explanatory framework to the hylomorphic account of substance in particular, see Bolton 1995 and 2010, and Charles 2000. Even these attempts, however, work most naturally as elucidations of the natures of kinds, rather than explanations of the existence of things, and must be squared with the claims in Phys. II 2 and elsewhere, mentioned earlier, that natural things are defined in terms of form and matter, like “snub.” My claim here is only that the application is far less obvious and cuts across, among other things, controversies about the nature and types of definition and definable things, as well as the structure and import of the middle books of the Metaphysics.

68  Causality and Causal Explanation in Aristotle The claim underlying the APo. schema, then, is that for any predicate that holds of a subject, there are four possible types of cause in virtue of which it holds, corresponding to four ways one can answer a question of the form: “Why is A B?” They are (1) by showing that A is B because of the essence of A;29 (2) by showing that A is derivatively B on the basis of more general facts that apply to A; (3) by showing that A is B because something prompts or prompted a change by which it became B; and (4) by showing that A is B for the sake of some further end, G. This group of four can in turn be simplified with reference to the conceptual bedrock distinction described earlier, between what is predicated (or explained or necessary) intrinsically (kath’hauto), and what is predicated (or explained or necessary) extrinsically (kat’allo, kath’heteron, kata sumbebêkos). From this standpoint, the APo. schema looks like it is comprised of one type of intrinsic causal explanation, where something is shown to bear a predicate “because of its being what it is,” and three types of extrinsic causal explanation, such that something is shown to bear a predicate in virtue of something else, or at least in virtue of something other than its being just what it is.30 This primary division appears indeed to be exhaustive—​if we can explain something’s having a property at all, it is either with reference to itself or to something else. If the further distinctions are accurate, they may also have a claim to be conceptually exhaustive of the ways in which we might explain something’s having a property. They are not exclusive, on the assumption that something can, for example, have a property both because of its essence and because of something else, but it is doubtful that these possibilities are relevant to the argumentative context here. On the whole, then, the four-​causal schema in the APo. seems not to be driven by the concerns of giving natural-​scientific explanation of things and changes, but rather by general considerations related to answering questions of the form “Why is A B?”, and to focus on the patterns of explanation more than the metaphysical relationships that may be involved, using primarily the conceptual tools of the rest of the Organon, without any implicit

29 This, at least, is the easy case: an obvious example would be the demonstration of an “intrinsic co-​incident,” e.g., risible could be shown to belong to humans in virtue of their essence (rational). It is less clear whether or how Aristotle means to include demonstrations that B holds of A in virtue of the definition of B, i.e., of the major term; the examples in APo. II 8–​10 are often read this way, but this is controversial. See Barnes 1994, 218–​21, 228, and Goldin 1999. 30 Alternatively, we might argue, if what applies to something in virtue of its genus is included, like the genus itself, in “what something is,” then we would have two types of intrinsic and two types of extrinsic causal explanation.

Background 2: Science and Dialectic  69 assumptions that natural beings are hylomorphic compounds. Aristotle is in this passage distinguishing explanatory roles and schemata, not metaphysical relationships. There are many reasons for him to do this, including especially the context of describing the nature of demonstrative science, but we cannot rule out other possibilities, including developmental ones.31 This schema is thus logically and metaphysically simpler than the one in the Physics, in that it uses more basic conceptual resources, and most notably is uncommitted to hylomorphic analyses of change and substance. It fits quite easily with and naturally complements Aristotle’s theory of predication, in particular the view that predicates can be exhaustively divided into those that hold of their subjects intrinsically and those that do not. I do not see good reason to suppose this schema is actually inconsistent with what we find elsewhere, but we should not minimize or ignore the differences either. And if that is right, it will make sense, as I shall argue, to consider what we are presented with in the Physics as an extension of this logically simpler account about the causes of predicational ties to the problems and practices of natural science, and the causes of natural things and their transformations, understood in terms of form and matter.32 The difference between the APo. and Phys. presentations of causes has often been a source of puzzlement, provoking either suspicions of profound change or attempts at assimilation which are often awkward. My hypothesis is intermediate between these: the Phys. schema is an extension of the simpler APo. schema, which could have grown out of reflections concerning the different ways a predicate might attach to its subject, whether in virtue of what that subject is or in virtue of something else. If it constitutes a theory, it has a certain simplicity and elegance, and the extension is a natural one, even if this is not the historical order in which the schemas were developed.

3.4.  Summary Besides his reactions to predecessors’ understandings of nature, then, Aristotle is also working within and reacting to a series of basic conceptual 31 I sketch some possibilities in Stein 2021, § 4. However, given that these distinctions bear the marks of Aristotelian dialectic and other concerns related to issues in works like the Topics, especially in light of the “general” cause’s connection to genus-​species relations, it makes sense to suppose that commentators have underestimated the Academic background to Aristotle’s thinking about causes. 32 Thus, unlike Graham 1987, I do not think this schema constitutes a “system” in its own right or that it is somehow incompatible with the application to natural things that we find in the Physics.

70  Causality and Causal Explanation in Aristotle commitments. Some concern explanation and understanding, such as the general idea that seeking essence-​specifying definitions is a primary goal of understanding, and the assumption that mathematics represents, for various reasons, the paradigm of scientific understanding. Others are even more basic, such as a general tendency to contrast things that hold of something intrinsically (kath’hauto) and what holds of them in another way—​in relation to something else, co-​incidentally, qualifiedly, or in virtue of something else, where these glosses are not exclusive of one another. These commitments are, I have suggested, on display in the four-​causal schema of the APo., which involves no commitment to hylomorphism or a causal account of things, but rather presents four types of cause by which any type of predicate might hold of any type of subject. One of them is because of the essence, and so intrinsic in the strict sense; the others involve reference to something else or to the thing itself in a more general aspect, and so do not hold of the subject because of its being just what it is. There is nonetheless a problem connected to these commitments, brought out in the discussion of Phys. II 2: if a science of nature depends on rendering change maximally intelligible, it seems to be at a disadvantage, insofar as our best explanatory tools are ones that apply to things that can be considered in isolation from change and matter, such as the tools of mathematics. All of these concerns underlie the work being done in Phys. II 2–​7.

4 Physics II 3 in Argumentative Context 4.1.  Highlights The aim of Part I has been to place Phys. II 3, or really II 2–​7, in relief against their argumentative and philosophical context, with a view to illuminating their key philosophical commitments and contrasts with what Aristotle takes to be the views of his predecessors. Several features of that discussion stand out as novel or striking in relation to this background. Some of them directly express philosophical theses about causes themselves, while others relate more to second-​order questions about one’s overall approach to causality. One key problem Aristotle thinks vitiates his predecessors’ views is that in one way or another, as we have seen, they end up with fewer than four types of transformation (metabolê). And, as we saw, at the root of this problem is especially a failure to grasp the correct concept of matter and its relation to natural change. The key features of matter in this regard are that it is, on the one hand, more determinate than some have allowed (i.e., the Platonists), since it constitutes an actuality or feature of a subject in virtue of which it is capable of existing, undergoing certain sorts of change, or bearing certain properties, but, on the other hand, as Phys. II 2 points out, it is also relative to each kind of change or thing which comes to be: there is no one type of material whose own nature would imply a restriction as to the kinds of transformation that could be genuine. Indeed, natural things as such cannot be defined without reference to their peculiar or proximate matter.1 This allows him to say that each type of natural transformation is irreducibly different

1 This point is made in Phys. II 2, though the emphasis there and in II 3 is on the matter of the products of generation; but it is continuous with the concept of matter developed in Phys. I and II 1, where the underlying subject of change, rather than generation, is more to the fore. This claim about defining natural kinds like ‘snub’ will, of course, come as a surprise to someone who thought that the way to define something was to take its genus and divide it by differentiae until he reached one that was necessarily co-​extensive with the original term to be defined. Because Aristotle’s claim is not given more detail, however, the force of his point about natural kinds is unclear and has yielded ongoing debate about Aristotle’s notion of definition and its relation to natural science.

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0005

72  Causality and Causal Explanation in Aristotle from the others, since they each occur in a different proper subject—​they do not all, for example, happen to body as such or atoms as such. This “introduction” of matter, rightly conceived, is not just a response to the predecessors’ views about nature but also a shift from the APo. schema, as I have argued. Accompanying that shift appears to be a change with respect to the explanatory role of general or generic facts. In the Phys. II passage (194b23–​32), genera are placed among causes of each mode, suggesting that the explanatory power of a thing’s genus is being accounted for as included in that of its form, nor is there any clear place for general causes which are not genera.2 To the extent that Aristotle recognizes here the possibility that something simply follows from something else taken as antecedently true, this, too, would seem to be shared among the different modes, and not peculiar to any one mode of explanation. Perhaps more important is the way in which Aristotle seems to reject explanatory reductionism in general. None of the modes of causation he describes posits either a special ontology or a privileged metaphysical or physical relationship. Indeed, even within each of the modes it is clear enough that there is no single metaphysical relationship that all instances of it have in common (a point I will discuss in more detail in Part II). For example, “form” or “essence” in this context indicates anything that is the endpoint of one of the types of transformation, as well as anything that determines a composite whole of some sort, just as matter indicates the proper subject of any transformation or entity that comes about through change, as well as the parts out of which any whole is constituted.3 Examples of efficient causes include people who deliberate, crafts, parents, “seed” (sperma), and in general “the agent” (to poioun) (194b30–​32, 195a21–​23). Similarly, and even more clearly, Aristotle draws a distinction between activities that are directly for the sake of some final end, on one hand, and activities and instruments whose direct ends are intermediate to some further end, on the other. (There are further important distinctions to be observed as well, as we shall see later.) The distinctions Aristotle draws between modes of causation are not between types of entity as such or even four determinate metaphysical 2 For example, an efficient cause may be a statue-​maker or more generically an artisan, as he says; I am assuming this point is meant to apply to all four modes, even though he does not explicitly make it for final causes. 3 Aristotle’s paired examples of material and formal causation in II 3, 195a16–​21, include letters of syllables, the matter of artifacts, fire and the other elements of the natural bodies, parts of wholes, and hypotheses of the conclusions, all broadly classified as subjects (hupokeimena) and essences (to ti ên einai).

Physics II 3 in Argumentative Context  73 relationships things may bear to each other, but rather between what we may call second-​order roles. To be something’s matter is to bear one or another of several determinate relationships to some composite entity; all of these relationships satisfy certain constraints and are closely related to one another, but they are not the same, nor are they obviously species under a common genus. This is not to say that there are no ontological commitments to the schema or that the relationships described are not grouped by way of their metaphysical characteristics. The four causes are not, as we shall see, metaphysically neutral or indefinite. Nor, of course, does Aristotle refrain from theoretical ontology: he of course draws ontological distinctions that go beyond ordinary concepts of what there is, and he picks out certain kinds of beings as fundamental. Rather, the point is that in the first instance, the determinate metaphysical roles or relations by which something is a material, formal, efficient, or final cause are not the immediate bases of the causal distinctions themselves, nor are these other ontological claims and distinctions. Even if we were to argue on the basis of what Aristotle says elsewhere that there is a way to reduce this variety to the “operation” of one special type of entity, such as substantial form—​though as we shall see this is not as promising as one might hope—​the position described is very different from a reductionist sort of view according to which all interactions are the product of one basic type of action or relationship such as Love and Strife, or condensation and rarefaction, or participation in an abstract Form.4 I will discuss the details and implications of this position in the next section, but here it will suffice to point out that Aristotle never claims that there is one way to be something’s matter, or the origin of a change, or “what it is to be” something, or to be “for the sake of ” something. Indeed, he regularly cites a surprising variety of things as causes, and makes a variety of statements and commitments that explicitly favor the idea that even each mode of causation is metaphysically pluralistic. (Besides the differences mentioned, we should consider also the difference between essential and co-​incidental predications and their respective “subjects”; moved and unmoved movers (e.g., Phys. VIII 5, 258a5–​8; GC I 7, 324a30–​34); and the two senses of “that for the sake of which” (e.g., Phys. II 2, 194a35–​36; DA II 4, 415b2–​3); as well as two passages in which Aristotle seems to state the point rather explicitly: one in Met. X 1 (1052b3–​18) and one in Met. XII 4–​5 (discussed later in Chapter 5).

4 Robin 1910 attempts to reduce all four modes in this way.

74  Causality and Causal Explanation in Aristotle Commentators nevertheless often loosely assume that each mode of causation pertains to one metaphysical relationship, and sometimes explicitly attempt to reduce this metaphysical variety, or even to come up with a general definition of ‘cause’. Each of these assumptions or attempts seems to be, from this perspective, not just something Aristotle thinks is a mistake, but something that undermines a part of what is supposed to make his view an improvement: if we take one type of entity or one type of relationship to be a cause strictly speaking, or even one mode of cause strictly speaking, we will inevitably end up either giving a specious explanation of some phenomenon or eliminating it from the science of nature, in the sense that we will have to deny that it has a genuine, intrinsic causal explanation. Just as the materialists discussed in Phys. II 8 turn good results of biological development into mere regularly occurring beneficial co-​incidences, so we would be forced to regard generation, or growth, or action, or some other important and persistent feature of the natural world, as merely co-​incidentally related to what brings it about. And this amounts to saying that some important component of nature is not intelligible in its own right, but not (Aristotle thinks) for any good reason. If this is correct, then this ontologically promiscuous aspect of Aristotle’s presentation, which tends to make it look at first glance as though he is speaking somewhat loosely or staying close to “ordinary talk,” is no accident. Another novelty, closely related to explanatory anti-​ reductionism, is Aristotle’s insistence on what I have called the Non-​Random Change principle, as well as what I take to be the closely connected principle that there are multiple intrinsic causes of natural phenomena. This is the claim in II 3 that: it follows that, as the causes are spoken of in many ways, there are also many causes of the same thing, not co-​incidentally; for example both sculpting craft and the bronze [are causes] of the statue, not in accordance with anything else [ou kath’heteron ti] except insofar as it is a statue, though not in the same way, but rather the one as matter and the other as the origin of the change. (195a4–​8)

It is one thing, that is, to point out that there are various sorts of natural regularity at varying levels of complexity—​not just inter-​elemental transformation but also the generation of living things, and generation that yields features that benefit each type of organism in the sense of promoting their abilities to engage in various life activities. It is much stronger to

Physics II 3 in Argumentative Context  75 claim that there are multiple causes for natural things that all relate to them intrinsically—​that is, that relate to them just insofar as they are those types of thing. Thus, whereas the Platonist might say that he does recognize an intrinsic cause of something’s coming to be F (the Form of Beauty itself that causes things to be beautiful, as in the Phaedo), answering to Aristotle’s own notion of a formal cause, Aristotle is claiming that natural things have intrinsic causes of this and other types, and that these intrinsic causal relationships are what account for the fact that in nature, we find that “nothing by nature either does whatever may chance, or is acted upon by whatever may chance, nor does just anything come to be out of just anything, unless we mean co-​incidentally” (I 5, 188a32). In this statement of our “first principle” he applies it to agents, patients (i.e., efficient and material causes of change), and what forms come about through change, but elsewhere, as we have seen, he extends it to final causes as well: “by nature exist whatever things, from some principle in themselves, by changing continuously, arrive at some end; but from each principle it is not the same [end] for each case, nor any chance one, though each always goes to the same [end], if nothing impedes” (II 8, 199b17). My suggestion, then, is that what Aristotle seems to present as a plain result of distinguishing four types of cause in II 3 is in fact a substantive point to which he does not call much attention here, but whose importance can hardly be overstated: it is a philosophical claim about what grounds the various aspects of observable natural regularities.5 Nevertheless, as the surrounding context in Phys. II makes clear, and as we will see in more detail, he is also willing to countenance a sense in which things have causes even if they do not have intrinsic causes. Intrinsically caused regularities, however, are the focus of the theory and present the paradigms for analysis. The importance of this commitment to the multiplicity of intrinsic causes is all the more striking when seen in light of the shift in explanandum between 5 Note that in Phys. II 5 he must take the trouble to say this: “for just as some things are intrinsically and some are co-​incidentally, so also it is possible to be a cause [intrinsically or co-​incidentally], for example, of a house, being skilled in housebuilding (to oikodomikon) is the cause intrinsically, while being pale or cultured [is the cause] co-​incidentally; the intrinsic cause is defined, while what is co-​ incidental is undefined; for infinitely many things may co-​incide in one thing” (196b24–​29). In this context we should note that even in the APo. presentation Aristotle does not distinguish causes from intrinsic causes. Arguably this is natural enough that we may assume such a distinction to be operating, since he is dealing with what can be scientifically demonstrated and what pertains to things intrinsically, in the senses laid down in APo. I 4, but his examples, which are often of particular events or individuals, suggest that he does not have the distinction in full view.

76  Causality and Causal Explanation in Aristotle the APo. schema and this one. Here we are no longer explaining predicational ties of any sort whatsoever, but things that come to be: generation, destruction, and every sort of change, and the beings and states of beings that result from such transformations. It is true that such phenomena can be treated analogously to predications, because of the assumption of hylomorphism, but that point is not emphasized, nor does Aristotle feel the need to point out that what we explain is the metaphysical analogue of predication. We are specifying the intrinsic causes of things—​or rather, since only regularities have intrinsic causes, we are specifying the intrinsic causes of those special things that have such causes and leaving aside as “co-​incidentally” caused those things that do not. We do not, I think, need to see this shift as a deep conceptual change for Aristotle with respect to the nature of things or their causes, though the move from general determination to matter is indeed striking. It is more appropriate, I think, to view it as an application of the general distinctions described in APo. II 11, which could apply to anything sufficiently complex to be treated as involving a predicate that holds or comes to hold of a subject, to the task of delineating the natures of a special class of phenomena, namely those whose regularity is due to their being the result of multiple intrinsic causal connections between themselves and what brings them about, and which are therefore plausible objects of scientific understanding.6 Again, whether or not this is the order in which Aristotle developed his view, it makes for a natural and elegant theory, and I suggest it as the best interpretation of the philosophical underpinning for the presentation of causality in Phys. II. Next, an interlocutor—​and, indeed, any reader—​might find somewhat bewildering the array of distinctions drawn from 195a29–​b30, between prior and posterior, simple and compound, proper (oikeiôs legomena, b4, presumably equivalent to intrinsic) and co-​incidental, and potential and actual causes, especially since these seem to be a mix of metaphysical and referential distinctions. It is especially puzzling that they include “co-​incidental

6 A further reason to think the two schemas are compatible is that Phys. II 7 uses what may be another way of referring to the “material” cause by its logical role. The point is somewhat confusing, but at 198b4–​9 he says that we must cite causes in all available ways, including, for matter, “that this must be if that is to be” (b7) where he seems to be indicating a necessary condition, rather than an antecedent which necessitates something else. This preserves at least the notion of antecedence that characterizes the general cause in APo. II 11, even if it seems to involve a different claim about what necessitates what. (On this passage see Schofield 1991, § IV.)

Physics II 3 in Argumentative Context  77 causes,” despite the fact that we have so far been talking only about intrinsic causes, or so we thought. I will further discuss these distinctions later (§ 8.2) as they pertain to efficient causes, but in this connection I think they serve three main purposes. One is that, since causes are not here functioning as middle terms by which predicates apply to subjects, but rather as the causes of things which are not obviously to be treated in the same way, Aristotle needs another way to bring out the manner in which an effect is rendered intelligible in light of its cause. These distinctions serve in part to isolate a way of referring to causes that makes their connection to the explanandum transparent. Second, and relatedly, these distinctions allow Aristotle to develop the notion of intrinsic causes, by highlighting the difference between explanatorily perspicuous descriptions of causes, and imprecise descriptions that merely pick out the cause without revealing its causal character. Plato, Empedocles, and Anaxagoras, we should recall, stand accused of naming goods such as Reason, Love, and the Good itself as causes, but not in the way in which they are causes—​as things “for the sake of which.” This mistake could reasonably be characterized as referring to causes not properly, but only co-​incidentally. Other mistakes of the predecessors could be cast as referring to them at too general a remove (perhaps some of the complaints about Forms are related to this possibility, or the complaint at GC II 9, 336a3–​12, that materialists treat things like Fire as though they were sufficient to produce certain determinate effects, when in fact they are not); or merely as potential (the Atomist explanation of generation in terms of association and dissociation, for example, criticized at GC I 2, 317a17–​31); or without going all the way back to the proper causal starting point, the “topmost” (akrôtaton) cause.7 Third, these distinctions allow Aristotle to deflect an important objection. By distinguishing causes in terms of second-​order roles which may in principle be occupied in a variety of ways by a variety of kinds of entity, Aristotle himself runs the risk of making causes turn out to be indefinite or indefinitely many, in just the way he accuses others of doing. After all, if a given change is the result of continuous change via several intermediate stages, and the occupants of these roles are not of any privileged ontological type, there would seem to be indefinitely many true ways in which we can refer to causes, even of a single change, and the problem would only seem to be exacerbated 7 This injunction to cite the topmost cause is puzzling and the source of some controversy. I also discuss it in more detail in § 8.2.

78  Causality and Causal Explanation in Aristotle by the wide array of natural and artificial entities, changes, and activities we hope to explain. Further, especially when we consider unique and chance occurrences, as Aristotle does in II 4–​6, which are ultimately not objects of scientific explanation according to this account, there will be indefinitely many causal claims which are roughly true but not scientifically precise, and potential explananda which are not genuinely explicable. Aristotle must be able to account for these in a systematic way. This is all the more important insofar as some reductionists (such as Empedocles), on Aristotle’s interpretation, would take what he considers to be co-​incidental causation as the norm and the model of causal interaction. If there are many reasonably appropriate but not fully precise ways of referring to causes, as well as infinitely many sophistical or at least explanatorily inaccurate ways of referring to them that cannot be ruled out in a principled way, the idea of grounding a science of nature in the right account of causes would seem to be hopeless.8 Some further novelties are worth noting, given the background we have already discussed. Plato would likely be surprised to see the same thing asserted to be the intrinsic cause of contrary properties, the way the ship’s pilot is the intrinsic cause of preserving the ship when present and, when absent, the cause of its destruction (195a11–​14). Even though Aristotle provides further distinctions (e.g., between actual and potential causes) which allow him to say, for example, that strictly speaking it is the present pilot that preserves it, and the inactive or absent pilot that destroys it, it is still one entity which is held to be the cause of both.9 Plato might also be surprised to find artifacts listed among the things having intrinsic causes; at least, it seems Aristotle thinks he should be.10 But the fact that artifacts no less than natural substances have intrinsic causes for Aristotle is clear, even though the status of artifacts as substances is not.11 As we shall see, understanding the precise import of this claim is crucial in several ways.12 8 Cf. Met. II 2, 994b27–​31: The chapter as a whole is concerned with the possibility of infinite chains of causes, but in closing he notes that if the forms of causes (eidê tôn aitiôn) were infinite, we wouldn’t have knowledge either. 9 Met. V 2, which is almost identical to Phys. II 3, adds a sentence to specify that both the presence and the absence of the pilot are moving causes (“aitia hôs kinounta,” 1013b15–​16). (Like most commentators I assume that the Physics version is the earlier one. See Menn 1995.) 10 Whether Plato countenanced Forms of artifacts is debated; see, e.g., Fine 1993, ch. 6. But Aristotle thinks at least that “we Academics” wrongly reject them: “and many other things come to be, such as houses or rings, of which we say there are no Forms” (Met. I 9, 991b4–​7). See also Proclus’s commentary on the Parmenides, III.10. 11 See §§ 6.1 and 11.2. 12 The closest suggestion to the contrary is the argumentative move at Phys. II 2, 194a21–​27, of supposing that craft imitates nature, but this is a supposition for the sake of argument, and cannot be

Physics II 3 in Argumentative Context  79 In sum, then, Phys. II 3 and its surrounding chapters present without argument a number of theses which differentiate Aristotle’s view from those of his predecessors, and which correspond to ways in which he has criticized them. In rejecting explanatory reductionism and its tendency to name a special ontology and privileged relations, he describes his causes in terms of second-​ order roles, which allows them to function across different ontological kinds (including artifacts) and with different types of metaphysical relationship between cause and effect. His principle about natural regularities (the Non-​ Random Change principle) yields a corresponding commitment to a multiplicity of types of intrinsic cause for such regularities—​causes which relate to what they cause precisely insofar as they come to be what they are. In terms of his overall approach to causal questions—​that is, to the second-​ order question I raised in the Introduction—​Aristotle offers a distinctive way of defining natural kinds, namely in terms of their arrays of intrinsic causes, especially matter (though as we shall see in more detail, not just matter). This constitutes an extension of the APo. schema for explaining predicational ties to the causal explanation of things and the transformations they undergo, and deploying these causal roles to say not just why such things occur but what they are. Explanatory power is achieved not by connecting phenomena to entities whose nature gives them a special claim on reality or causal power, the way only Beauty itself is beautiful without qualification, but rather by isolating a precise and causally perspicuous way of picking out just those aspects of things that relate non-​co-​incidentally to what is brought about.

4.2.  Implications for Theory and Method If we had to give a capsule statement of a “standard” view of Aristotle’s theory of causation, it would be something like this: “Aristotle thinks that in order to explain a thing, such as an artifact or a natural substance, we need to cite four things about it, because he identifies four distinct metaphysical relationships as causal or causally relevant: being something’s form, being something’s matter, being the mover that brings something about, and being what something is ‘for’.”

read as denying a stronger relation; further, it is directed at clarifying the scope of natural science, not making a point about causes as such in either domain.

80  Causality and Causal Explanation in Aristotle I think it follows from the preceding that this capsule statement is at best only partially or loosely speaking true, and the ways in which it is inaccurate are important. First, Aristotle’s distinctions among modes of causality in the Physics are not rooted in the first instance in a theory about things, but are rather the result of extending a theory about predication to a special class of natural phenomena. They represent the application of a schema for explaining predications as holding of a subject either intrinsically or extrinsically to the explanation of things which admit of being treated in a way suitably analogous to predications, as well as to the various kinds of transformation that produce them and which they undergo, and the features that they have. He holds in addition that a special class of phenomena, because they are intrinsically (kath’hauto) related to what brings them about, exhibit the kind of stability that makes them legitimate candidates for scientific understanding, such that citing their intrinsic causes also amounts to saying what they are. The four causes are thus conceptually connected insofar as they represent the different grounds by which a predicate might hold or come to hold of a subject (i.e., with reference to the simple schema), not because they are jointly necessary for explaining a special kind of object (e.g., craft production or substance), however much that might be true. Second, Aristotle does not distinguish four metaphysical relationships, but rather second-​order roles, each of which is satisfied by several distinct relationships—​whose number, nature, and relationships to each other need clarification. Loosely speaking, we can say that one mode of causation is material causation, but this covers a metaphysical variety that Aristotle thinks is important, both because he generally thinks that more determinate relationships take precedence over the kinds of commonality by which we might be able to group them together, but also because recognizing these differences is important for his explanatory anti-​reductionism. The shift in application from a schema for causal explanations of predications, which do not necessarily converge or overlap, to a schema for explaining things and their intrinsically causal definitions which generally do overlap, does not lead, I think, to any obvious conflict or inconsistency, though certain debates about various aspects of Aristotle’s physical theory are indicative of some conceptual strain.13 If the two schemas are consistent, we 13 For instance, questions about the explanatory role of essences, the nature of substantial form and substantial generation, and their connection to the essences of natural substances. Some of the issues debated in this context, to which I will return later, seem to me to turn on how a predication-​based schema can be applied to things and transformations.

Physics II 3 in Argumentative Context  81 should recognize two types of causal explanation to which these distinctions are relevant in natural science: the explanation of a predicate’s holding of something as a subject (corresponding to a straightforward application of the simple schema), and causal explanations of the things themselves (broadly construed to include any stable regularity, including the transformations that yield things like substances, and the changes that yield their inherent properties). The former is expressed independently of hylomorphism, while the latter requires it. Thus, just as Aristotle treats the notion of substance in different ways in the Organon and in the physical and metaphysical works, such that the latter involves applying the distinction between matter and form, so there is a mode of causal explanation that works with general conceptual tools, especially those of the Organon, and one which deploys and requires the tools and commitments of hylomorphism.14 Commentators, I think, tend to recognize the diversity within Aristotle’s modes of causation, but still betray an ambivalence about it, with a tendency to treat each mode as nonetheless basically reducing to one kind of relationship, and to treat substances and/​or their models, that is, artifacts, as conceptually basic with respect to causes. I will say more about the metaphysical pluralism within the modes in the next section, but it is important at this stage to appreciate the point that things or substances are not conceptually basic to Aristotle’s theory of causality. However much Aristotle thinks that substances are ontologically basic, and that substance (ousia) is somehow conceptually basic with respect to the study of “being” (to on), he gives us no reason to think that the causes of substances are causes more properly speaking than the causes of anything else that has intrinsic causes—​in particular he gives us no reasons for thinking that the causes of change are only causes in a secondary sense, and indeed substance as such is hardly a preoccupation in these chapters of the Physics.15 It would indeed be problematic 14 The discussion of the two ways of treating substance is important and wide-​ranging, especially as it concerns the interpretation of Met. VII and its relation to the discussion of substance in the Categories. See especially the classic exploration of the issue in Burnyeat 2001. Given that discussion, it seems best to conclude that the two modes of thinking about causes can persist alongside one another, but again, Aristotle does not set the notion of cause as a problem for philosophical inquiry the way he does for substance, so there is also less evidence about different conceptions he may have had. 15 Aristotle does say, in one passage in GC I 4, that “the matter most strictly speaking (malista kuriôs) is the subject that admits of generation and destruction, but also in a way the [subject] for the other transformations, since all of the subjects are capable of admitting certain contraries” (320a2–​ 5). I discuss this passage more fully later (§ 7.3 and p. 145 n. 29), but it should not be read as stating that the matter of a substance is more properly speaking a material cause than the material subject of change. Where Aristotle presents matter in Phys I and discusses the causes more broadly in Phys. II, there is no suggestion that the material or other causes of change are causes only in a secondary sense of ‘cause’.

82  Causality and Causal Explanation in Aristotle if he made substance conceptually fundamental to the notion of causation as such, since he wishes, in Met. VII, to use the latter to explain the former. He cannot have it both ways, and I do not think he tries. We should likewise be wary of the traditional metaphysical distinction between what are sometimes labeled “intrinsic” and “extrinsic” causes (here using these terms to indicate a rough distinction between internal and external), which divides the formal and material causes (“intrinsic”) from the efficient and final causes (“extrinsic”).16 That distinction works reasonably well for artifacts, but, as we shall see in more detail in Part II, it does not broadly apply in any straightforward way to the kinds of natural phenomenon Aristotle wishes to explain, and it is a mistake to treat it as though it is relevant to the conceptual core of the schema. So if we were to give a revised capsule statement of Aristotle’s theory in the most general terms, we should say he aims to give a complete account of how there can be—​and how we can understand—​anything which is not metaphysically or analytically simple, but instead to be analyzed in broadly subject-​predicate terms. There are in general four ways in which such facts may be explained, not as a rule exclusive of one another, but not obviously mutually requiring one another either, such that any one might in principle be sufficient for a scientific explanation. This schema for understanding facts can in turn be applied to the understanding of natural things, which have an analogous structure. In this application, however, a scientific explanation does require more than one cause, especially (but not only) because for natural things there is a special dependence relationship between the occupants of the subject and predicate positions, since the compounds they comprise are essentially such as to be generated and destroyed, and therefore must be defined in a way that captures their matter.

4.3.  Causal Pluralism Another fundamental part of the theory, and part of Aristotle’s response to his predecessors as well, is, of course, the pluralism itself, but we should clarify what this amounts to. After all, he has criticized his predecessors for wrongly excluding one or another of what he recognizes as genuine causes, suggesting 16 Aristotle distinguishes efficient causes as external, in contrast to “inherent” (enuparchonta) causes (form and matter) at Met. XII 4, 1070b22–​26, without mentioning final causes explicitly; the two-​by-​two contrast is found, for example, in Aquinas, De Principiis Naturae, ch. 3, cc. 20.

Physics II 3 in Argumentative Context  83 that somehow they ought to have recognized all of the modes he does, but he has not said what it is that these relationships all have in common, in virtue of which they all ought to be grouped together under a common term, however important their differences; nor has he said how they all answer to whatever it is he thinks his predecessors were looking for. I have argued elsewhere that the aforementioned challenge is a genuine one which deserves a good answer, and that ‘aitia’ is usefully thought of as following the model of a ‘pros hen’ term, with a primary sense or use in terms of which the others may be defined.17 In particular, I claim that the formal cause is conceptually primary, even if we might be tempted to say, with Aquinas among others, that for the special case of natural substances, the final cause is “the cause of causes,” insofar as a given natural thing’s form, matter, and efficient cause are ultimately determined according to the activity that constitutes its natural end or “function.”18 I have given further reason here to take formal causation as conceptually primary. It makes sense to take the notion of being something “in virtue of itself ” as prior to that of being something “co-​incidentally” or in virtue of something else, and that this is Aristotle’s view seems supported by his distinction in Met. V 18, 1022a14–​22, between primary and secondary senses of ‘in virtue of ’ (kath’ho), which he applies directly to the distinction between the formal cause and the others. Still, one might object that we have not been given any informative account of what it is to be a cause, either full-​stop or in any of the modes, but Aristotle owes us one if he wishes to argue with his predecessors about which things really are causes and which are not. He certainly does not give a reductive definition of the sort Hume famously gives, nor does he give non-​ reductive definitions of the sort he gives for change (at Phys. III 1, 201a11) or even a general outline of the sort he gives for soul (at DA II 1, 412b4–​6).19 He introduces the modes and gives examples, but “the primary principle from

17 In Stein 2011, I focus on issues related to Aristotle’s claim that ‘cause’ is multivocal, i.e., “said in many ways,” and whether there is or could be a single overarching sense of the term that applies to all four causes, so I will not rehearse those arguments here. The position I describe there, however, does not take into account the differences noted here between the APo. schema and the Phys. schema, and it focuses more on questions related to the kind of conceptual pluralism at stake. 18 Further discussed in Chapter 8. Aquinas describes the final cause this way in his commentary on Phys. II 3, lect. V, § 11, but without suggesting that this description is only limited in scope. 19 Suárez gives what is probably the most prominent such definition, as a principle that “inflows being” to something else (“Causa est Principium per se influens esse in aliud,” DM XII.2.4), but I do not think that it will do. Indeed, its defects serve to highlight reasons for which it seems wrong to expect Aristotle to give one.

84  Causality and Causal Explanation in Aristotle which the transformation or rest originates” is hardly an informative definition if we have a philosophical question about what makes something an efficient cause, and likewise for the other capsule statements about the different modes. Nor do his examples or glosses in these passages really seem intended to serve as definitions or to capture their extensions in an exhaustive way. What kind of conceptual clarity or unification should we expect, then, and does Aristotle say anything that can satisfy this demand? Aristotle does briefly discuss the term ‘aitia’, in Met. X 1, saying that it is like ‘one’ and ‘element,’ and refers obscurely to the possibility that some uses are “closer to the name” while others are “closer to the power” (1052b6–​7). Commentators have justifiably found the passage more perplexing than illuminating.20 After distinguishing several ways of being ‘one’, Aristotle points out that they all involve some form of indivisibility, but that we must not confound the task of saying “what sorts of thing are said to be one,” with that of saying “what being is for one and what its account is” (1052b1–​3). The clearest part of the passage points out that fire’s essence is independent of the fact that it is an element, even if it is an element; rather, it is an element in virtue of its having a given nature such that something is made of it as a primary constituent (1052b9–​24). The point thus appears to be that ‘element’, and so also ‘one’ and ‘cause’, pick out things that are (a) defined independently of these terms and (b) bear them by satisfying a certain role in virtue of their own independent natures. Thus, for example, fire is not a determinate or species in the general class of ‘element’, in the way that circular motion is a determinate form of change. Nonetheless, the terms apply to their bearers, even if some uses do not do much more than say that something is a cause or element, while others pick out more clearly the feature (i.e., the “power”) by which it merits the term. So we can say vaguely that statue-​makers are causes of statues, or more perspicuously that they make or sculpt them by exercising their craftsmanship. For our purposes, the value of this discussion is less clear, insofar as the point is independent of the multivocity of ‘one’ and ‘cause’. (‘Element’ is also multivocal, Aristotle says, but is more unified as a term in that there is a clear commonality to all the uses; in any case, neither its multivocity nor that of ‘cause’ is at issue in the passage from Met. X 1.) It may be that the uses “closer to the name” are simply those that evoke one or another causal notion,



20 See especially Natali 2013, § 2.4, and Castelli 2018, commentary ad loc.

Physics II 3 in Argumentative Context  85 without specifically implying anything about the determinate features in virtue of which something functions as a cause of that type. I think that the passage not only does not give us much grounds for thinking that there is an informative univocal definition of ‘aitia’; it rather gives a reasonable basis for thinking that we should not expect one. The reason Aristotle thinks we need to be careful with terms like ‘element’ and ‘cause’ is that they indicate roles, the specifications of which do not describe the essences or attributes of any of the things that fall under their extension, nor do they tell us anything specific about what determinate features of a given entity merit its inclusion. The point applies doubly for ‘cause,’ if I am correct, since none of the causal modes is in fact constituted by a single metaphysical relationship. Still, one might point out, Aristotle does not think we can give a proper “real” definition of soul (psuchê) either, since he claims that the particular kinds of soul—​nutritive soul, perceptual soul, intellectual soul—​are the proper objects of definition (DA II 3, 414b19–​34). Yet he nevertheless gives us an informative account of soul couched in technical terms—​it is “the first actuality of a natural organic body” (412b5–​6)—​which constitutes a philosophical commitment that distinguishes his approach from those of his predecessors. Why cannot he do the same for ‘aitia’, the way Suárez attempts to do in giving his account of a cause as a principle that “inflows being” to something else? One reason we should not expect much from a potential single sense of ‘aitia’ is that, unlike ‘psuchê’, this usage of it to characterize the aims of scientific investigation is already a term of philosophical art, even if there are related, everyday uses of ‘aitia’ and ‘aition’. As has been well-​documented by Natali (2013), the original senses of ‘accusation’, ‘blame’, and above all, ‘responsibility’ co-​exist in Plato’s writings with a distinct usage indicating an object of special interest for philosophy, dramatically in the Phaedo but no less important in later dialogues like the Philebus. In the Phaedo the term is explicitly invoked to compare Socratic/​Platonic inquiry with the efforts of the early naturalists like Anaxagoras, whereas in the Philebus it is one of the four “kinds” (genê) alongside Limit, Unlimited, and Mixture (23c–​d). This marks a difference from the many philosophical inquiries which focus on a concept whose nature and extension are disputed in ordinary or philosophical life, but which do answer roughly enough, even in technical discussions, to common uses of a common term. The paradigms of Socratic ethical inquiry, for example, start with a term in common use (virtue,

86  Causality and Causal Explanation in Aristotle knowledge, etc.) and seek to understand what the term indicates in a way that corresponds at least roughly with the function or meaning of the term as commonly used. When we do this, we are aiming to understand the precise nature of something we take ourselves to have as a shared object of discussion and thought, under a shared term. Plato’s discussion of ‘aitiai’ is not like that, nor is Aristotle’s. There is no dialogue in which Socrates confronts someone who thinks he is an expert about aitiai, nor does Aristotle present a rehearsal of the endoxa of the many about causes, or set up the puzzles that result for eventual resolution. Met. I does present and criticize the views of previous theorists, which are perhaps endoxa in the sense of being opinions of the “wise” (cf. Top. I 1, 100b21–​23), though not expressed by them as opinions about “aitiai,” and Met. II presents some relevant puzzles (mainly about principles, ‘archai’), but the critiques and puzzles pertain to a specialist investigation. Both of them think their predecessors are wrong about aitiai, but not because they have a misconception of some common notion, the way a hedonist does about happiness or even the way Meno has misguided ideas about what characterizes a satisfying answer to a “what is it” (ti esti) question.21 Nor do they criticize their predecessors for having a mistaken conception of anything like the meaning or use of the terms ‘aitia’ or ‘archê’, which they seem to apply retrospectively. ‘Aitia’ in this usage is a term of philosophical art, not unrelated to the “original” sense but not constrained by it or by common understandings of it either, which Plato and Aristotle use to mark out just those entities and relationships that are of special importance for knowledge or understanding of the highest sort one can achieve—​ knowledge which takes us past the mere facts and appearances to whatever it is that makes them hold. Aristotle’s examples and the considerations he takes to be relevant bear this out: ordinary uses of the term simply are not relevant. Even the discussion in Phys. II 4–​6 of whether luck and chance are causes is primarily a debate with philosophical predecessors, not with “the many.” It is a mistake, then, to look for a single informative definition of ‘aitia’ for two reasons. We should not expect a reference-​fixing, “nominal” or conceptual definition, because Aristotle is not pursuing an investigation that begins with a common notion, disputes about which are explicit in everyday thinking (in contrast, say, with his discussion of ‘eudaimonia’).22 Nor should we expect a “real” definition of the sort given by Suárez, since Aristotle 21 At Meno 74b2–​76e9. 22 The nature and use of Aristotle’s “endoxic method” is contested; see D. Frede 2012 for a recent discussion.

Physics II 3 in Argumentative Context  87 does not treat causes as such as an object of theoretical inquiry the way he treats substance, and because he gives priority to the determinate roles and relationships that he thinks satisfy the goals of inquiry. ‘Aitia’ and ‘aition’ are theoretical terms, or terms being theoretically repurposed for a specialist role, which might at best be given a functional definition of the sort I have just sketched. As a theoretical term, unity of the sort that I have suggested derives from their connection to predication and is probably the strongest sort available. In terms of its philosophical commitments, therefore, Aristotle’s discussion of causes has perhaps more in common with recent work in the philosophy of mathematics or philosophical logic than it does, for example, with recent work in the metaphysics of singular causation. We have a basic idea that there is a difference between good and bad reasoning, but even though the technical terms of logic are related to ordinary usage, none of the ordinary uses of those terms sets the boundaries or the content of the investigation, nor are non-​expert opinions really constraining in general. Rather, we introduce or repurpose terms in order to distinguish an area of inquiry and dispute, one which is not clearly identified as such by ordinary terminology or practice. Likewise, Aristotle’s treatment of causes is primarily responding to the demands of specialist inquiry, even if that inquiry is rooted in a basic aim of human rationality.

4.4.  Strengths, Weaknesses, and Open Questions How, finally, should we evaluate Aristotle’s account thus far, as I have reconstructed it, both in general and as a response to the kinds of reductionism he wishes to reject? I think it is important that the view appeals to something so conceptually basic as predication for its starting point, if he is to reject various kinds of explanatory reductionism. After all, these views are perennially appealing for good reason, and it will not do simply to point out that things like statues and people have apparently stable natures, which arise from regular processes of generation out of pre-​existent material, and are in some sense irreducibly teleological. This holds especially if these explanatorily reductionist views are accompanied by claims that are either themselves ontologically reductionist or in other ways reject Aristotle’s views about the nature of individual, perceptible substances. So it is perhaps a point in his favor (and in favor of my

88  Causality and Causal Explanation in Aristotle interpretation) that he can nonetheless connect his analysis of causation to something that has a claim to being conceptually fundamental as well, and hence can ground the epistemological importance of knowing causes. This also allows him to justify his application of the term to all four modes, rather than taking it as somehow primitive that these and only these relationships are appropriately considered causal ones. On this reading, he has transformed the notion of causal inquiry from a search for ultimate, privileged entities to a mode of inquiry that can be adapted to various domains both within natural science and beyond it, so long as there are genuine kinds of change or “coming-​to-​be” that can be objectively distinguished. There will still be a role for privileged basic entities as ultimate starting points. Indeed, different sciences will all have their own ultimate principles, whether these are something like basic properties or axioms, and in some contexts a single entity or type of entity may occupy a fundamental role, the way the sun is singled out as being responsible for the cycles of generation and destruction in nature (GC II 11, 338b2–​19, cf. Phys. II 2, 194b13). However, these are not directly required for any intrinsic causal claim to be grounded, nor are they theoretical constraints on causal explanation; rather, the ontological neutrality of the theory allows Aristotle to frame his accounts of the structure of the sciences and the types of foundations they may have. It is also probably a virtue of the view that one can accept quite a lot of Aristotle’s theory before making any substantive commitments about controversial topics such as the nature of natural beings, substances, or teleology. The simple schema seems acceptable on the basis of very minimal commitments. The application to things of the Phys. II schema is more robust insofar as it appeals to Aristotle’s hylomorphism, but it is not obvious that, in order to accept it, one must also accept Aristotle’s own version of hylomorphism, natural teleology, and the like—​some of which he presents as the results of observation rather than as conceptual requirements of an adequate understanding of causes. One might accept both components of his view thus far, for example, and still think that it is at least an open question whether living beings or all of their activity-​promoting features have intrinsic efficient causes. It is useful to have some separation between these controversial metaphysical topics and Aristotle’s view of causes, which, I have suggested, seems in many ways quite reasonable, and in other respects seems like it should be controversial for reasons other than those that pertain to special topics like substance.

Physics II 3 in Argumentative Context  89 Aristotle can also to a large extent make good on at least one aspect of his criticisms of his predecessors, which have sometimes struck commentators as unfair, especially to Plato. On this reading, he is not unfairly dismissing or ignoring previous attempts to specify something that more or less does what his causes are supposed to do, the way Plato’s receptacle is clearly something like a material cause.23 Instead, he has reasonably clear views about why these attempts fail to preserve the explanatory value of the different modes—​for example, by treating genuine causes as mere conditions. At the same time, just as with other metaphysically “minimalist” views, there is pressure on Aristotle to say why we should take this to be a theory of causation, that is, one that yields genuine explanatory power, as opposed to a system for giving more accurate descriptions of what happens. After all, despite their drawbacks, reductionist views are on strong ground in claiming that if they are right, grasping causes will confer knowledge in terms of something that has genuine metaphysical priority over what it causes. What can Aristotle say in reply? A great deal depends on giving a plausible account of the notion of an intrinsic cause, in particular how intrinsicality can rightly be extended from the subject-​predicate relation to the whole variety of causal relations.24 We might challenge that extension, since fact-​explanation and thing-​or change-​explanation could be very different. There might be a variety of ways in which we could explain facts such as males in population P outnumber females by a 2:1 ratio, or humans tend to be born either left-​handed or right-​ handed, only some of which would be causal explanations even in a broad sense. So Aristotle needs to say how the predications that have the right form for being explicable on the simple schema might be restricted to those that ought to be causally explained, if he is to justify the thought that the Physics constitutes a legitimate extension of that schema. One might also press Aristotle on the following point. I have argued that what are distinguished in Phys. II 3 are second-​order roles, rather than types of occupants of those roles or distinct metaphysical relations. Still, roles like this ought to be subject to some sort of schematic definition, with clear criteria for what counts as a way of being matter, or a source of change, or an 23 For the complaint that Aristotle is unfair to Plato, see, e.g., Ross 1924, vol. 1, 176–​77. 24 To a large extent the work of Part II is connected to this burden, a response to which I think can only be evaluated with a relatively detailed account of how causes relate to what they cause. The distinction may nevertheless be basic, so while we are entitled to expect an account, it may not be an analysis. On the general distinction between intrinsic and co-​incidental causes, see also Charles 1984, 46–​47; Freeland 1991, § 1; D. Frede 1992; and Meyer 1992, § 3.

90  Causality and Causal Explanation in Aristotle end, or “what something is.” Does he have such criteria, and can he give such an account? Further objections one might raise, from a modern perspective, include worries about anti-​reductionism and its scope. Perhaps, one might argue, the forms of explanatory reductionism attempted by his predecessors are not terribly sophisticated in the end, and even if he is right to find fault with them, other, more sophisticated types can succeed. Alternatively or in addition, one might allow that we can give causal explanations of this sort for certain natural kinds of change and being, but that Aristotle misconstrues the scope or importance of what can be explained in this way. Perhaps this kind of explanation is of interest for certain complex systems, but it is inadequate for representing and explaining more basic types of physical process: arguably, these more basic phenomena, such as those governed by fundamental laws, should not even be thought of as causal at all, but they nevertheless fall within the scope of natural science. Finally, one might raise a question as to the nature of this “causal pluralism,” in comparison with other views to which the label is applied. Aristotle’s view, for example, is rather different from the kind of conceptual pluralism espoused by Hall (2004a), who argues that we have competing concepts of “production” and “difference-​making” types of causal relation, such that we create confusion by failing to differentiate them. While Aristotle does think that previous thinkers failed to isolate or distinguish these four modes, he does not think that in the end they are concepts we have that overlap in many but not all cases, nor, as I have argued earlier, is his pluralism tied to any particular worries about ordinary or “folk” concepts. Rather, he thinks that when we appreciate them correctly, we see them as genuinely distinct roles which are mutually complementary in some cases. To the extent that he might think there are one or many “concepts” of cause that govern our attempts at specifying the goals of inquiry, his claims that these roles represent a complete account of what his predecessors were searching for argues in favor of a single concept, however inarticulate.25 Instead, he is thus far committed to two types of pluralism, which we can label horizontal and vertical pluralism. Horizontal pluralism is the view that there are multiple co-​ ordinate distinctions between four types of cause that are neither reducible to nor overlapping with one another, all of which answer to the theoretical 25 One might argue, on the other hand, that the difference we have seen between the APo. predication-​based schema and the Physics schema does indicate a conceptual shift; though again, it does not appear that the two schemas would result in rival explanations of the same explanandum.

Physics II 3 in Argumentative Context  91 role that constitutes the aim, implicit or explicit, of the “specialist” search for the principles by which things, especially those of the natural world, can be understood.26 Vertical pluralism, which I shall discuss in more detail in the next section, is the view that within any single mode of causation there are more determinate subtypes, whose relationship to one another is so far an open question.27 More needs to be said about the metaphysical and epistemological features of Aristotle’s view to appreciate these and other potential objections. At this stage, however, I think it is enough to appreciate that if these are the type of objections to which the view is subject—​matters of scope, sophistication, and explanatory power—​they represent important points to contend with for any interesting theory of causation. Insofar as I have been attempting to see whether Aristotle has something that constitutes a theory of causation, in the sense of a core philosophical position and approach that can be criticized and developed, these objections are welcome.



26 Or perhaps, not quite co-​ordinate, if one mode is primary, as I have suggested. 27 For a discussion of causal pluralism in general, see Godfrey-​Smith 2009.

PART II

META PHYSIC S

5 The Realist Challenge 5.1.  Metaphysical Pluralism I have argued that the distinctions Aristotle draws between the four modes of causality do not correspond to four distinct metaphysical relationships. Rather, as part of his rejection of different kinds of reductionism, he distinguishes second-​order roles that are themselves occupied by a variety of different metaphysical roles something may play with respect to a given explanandum. This general approach to causal explanation is not just metaphysically open-​ended, but rather rejects the idea that causal explanation essentially requires appeal to any particular ontological kind or metaphysically privileged relationship. When we turn to the Physics, then, we must bear in mind that Aristotle is applying this basic approach to a special set of cases: not just the explanation of things rather than true predications, and not just things that are caused, but specifically those regularities that are to be explained in terms of intrinsic causes. This kind of metaphysical open-​endedness is appealing in certain respects, especially if we are moved by Aristotle’s concerns about reductionism, but it comes at a cost and raises worries of its own. Different kinds of reductionism are attractive, in part, because they offer clear answers to questions about the kind of priority causes seem to have over their effects, and why causes have special metaphysical and epistemological status. These are legitimate concerns, but if Aristotle is committed not just to what I have called horizontal pluralism, but also vertical pluralism within each mode, it is not clear what kind of answer he can give. That Aristotle does recognize at least some broad differences within each mode is reasonably clear, as we have already seen. Formal causes are, of course, divided into substantial forms and those in the other categories, with corresponding differences between material causes for substances and for non-​substantial changes or properties.1 They would also include the kind of mediated causality whereby a form or essence is responsible for a 1 That there is a distinction is beyond dispute (see especially Phys. I 7, and Met. VII 13, 1038b3–​6, for its application to the notion of an underlying subject). Its nature and consequences are very much

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0006

96  Causality and Causal Explanation in Aristotle subject’s having some further property, the way properties like a capacity to learn language follows from being a human (the so-​called propria). Efficient causes are also subject to a variety of distinctions, not just between ultimate and instrumental efficient causes but also between agents and other types of mover.2 In many paradigm cases, efficient-​causation involves both an initial, “unmoved” principle in the primary efficient cause (e.g., a substance like an artisan or an animal capable of reproducing one of its own kind), as well as a materially embedded, proximate, moved mover (e.g., an artisan’s hands or tools, or animal “seed”), in addition to any intermediate movers—​and Aristotle calls both moved and unmoved movers intrinsic efficient causes.3 Finally, given Aristotle’s examples of final causes, it is also clear that there are varying relationships between an explanandum and what it is for the sake of: there are again intermediate and ultimate ends, and again tools (in a broad sense) are distinguished from goal-​directed activities (Phys. II 3, 195a1–​3). Aristotle also, in several places, distinguishes between two senses of “that for the sake of which,” one which takes a genitive construction and one which takes a dative: ‘heneka tou’ and ‘heneka tini’.4 The nature of the distinction is controversial, but I agree with recent commentators that both are genuine and distinct teleological relationships. An example of “end-​genitive” final causation would be a production relation, the way sculpting is for the disputed, since it is directly related to the problem of substance. An especially important and influential discussion of the problems arising from this distinction is Gill 1989. 2 See GC I 6, 323a12–​20, and GC I 7, esp. 324a24–​b14. For a careful study of the variety of phenomena that Aristotle considered “principles from which a change originates,” and the way in which they came to be incorrectly assimilated to the more restricted notion of a producing (poiêtikos) agent like a sculptor, yielding among other results the misleading label ‘efficient cause’, see Gourinat 2013. 3 This much, that many intrinsic efficient causes without qualification are moved movers, is clear: the example of seed in the canonical Phys. II 3, 195a21, makes this evident (likewise GA II 1, 732b23), as does the fact that he thinks the efficient causes of the cyclical causal processes of nature include not just local efficient causes, but the cyclical movement of the sun along the ecliptic as well (Phys. II 2, 194b13, GC II 10, 336a31–​337a33). Indeed, Aristotle is explicit that the study of nature is of things that bring about change by themselves being changed (kinoumena kinei), and whatever is not like this is no longer an object of natural science (Phys. II 7, 198a27–​31). Cf. Met. XII 5, 1071a14–​ 17, and Judson’s 2019 commentary, 125–​26, 165. It is unclear how to square these claims with some of what Aristotle says about two other classifications—​self-​movers and unmoved movers. On these topics, Aristotle is ambivalent and commentators are divided—​some are doubtful he can give a coherent picture that preserves all of his claims. A classic on the topic of self-​movers is Furley 1994 (and see the other papers in Gill and Lennox 1994). But the study of nature already includes that of the movements of non-​living things that are not self-​movers but nonetheless have an internal principle of change or rest, such as the elements and the non-​living compounds made out of them, as well as many of the processes involved in the generation and activities of living beings. I discuss some of these issues, including the “unmoved” principle in many causal processes, in § 8.2–​3. 4 See, e.g., Phys. II 2, 194a35–​6, DA II 4, 415b2–​3, and Met. XII 7, 1072b1–​3. For recent discussions see Johansen 2015 and Gelber 2018.

The Realist Challenge  97 sake of a finished sculpture, while an example of the (more controversial) “end-​dative” final causation would be the way in which sense organs contribute to an animal’s activities of being aware of its environment, moving around, seeking food, and so on—​sense organs are for the sake of being used or deployed in those activities of the animal that has them already, and not by producing or transforming anything. Aristotle also expresses an explicit commitment to a kind of vertical pluralism in a key passage from Met. XII 4: There are, in one way, different causes and principles for different things; but in another way, if one speaks universally and by analogy, they are the same for all things. . . . Or, just as we say, in one way they are, in another way they are not [the same]; for example, perhaps among perceptible bodies, in one way the hot is the form, and in another way the cold is the privation, while the matter is what is primarily and intrinsically capable of being these things; and both these and the things made out of them are substances, of which these are principles, or if something one comes to be out of hot and cold, such as flesh or bone; for necessarily what comes to be from these things is different. So then, the elements and principles of these things are the same (and there are others of other things), but we cannot speak this way of everything, except by analogy, just as if someone were to say that there are three principles, the form and the privation and the matter. But each of those is different in relation to each kind, for example in colors, pale, dark, and surface, or light, shadow, and air; and out of these things come day and night. (1070a31–​b21)

There are a variety of puzzles about this passage, but the overall aim is, minimally, to deny that there can be a universal type of cause that occupies a given causal role across a wide variety of natural phenomena. In explaining things that are of different categories—​for example, something’s coming to have a given quality or something’s coming to be full-​stop—​the occupants of the different roles are only the same analogously, in virtue of occupying the role. Aristotle offers two main grounds for thinking this, even if the scope of his restrictions is not entirely clear. First, he argues that when we are dealing with things of different categories, there can be no single class of beings that constitute the elements of everything, since there can be nothing “common

98  Causality and Causal Explanation in Aristotle to be distinct from” substance and the other categories (1070a33–​b10). Second, the distinction between actuality and potentiality is different for different sorts of thing: “But those things for which the matter is not the same, and of which the form is not the same but rather different, also differ in relation to actuality and potentiality” (XII 5, 1071a11–​13), which affects not just what we take the matter to be but also their formal and efficient causes (1071a13–​17). Things do, he admits, have the same causes in a different metaphysical sense, insofar everything depends ultimately on substance, but this is in a way beside the point when we wish to understand the intrinsic causes, principles, or elements of things.5 The only clear case, in fact, in which different things have the same type of cause is when they are different individuals within the same species, though even here he is keen to make a point that somehow (the exact point is highly controversial) there is still no universal cause that is shared by individuals (1071a17–​29).6 Aristotle evidently wishes to deny not only a privileged ontological class for causes among different types of explananda but even, at least to some extent, that causes are of the same sort within any given generic type of explanandum. That is, what occupies the role of matter for, say, an interaction like curdling is different from the matter of a human being, but so also the causes for an animal are importantly different from those for a natural compound, a plant, and so on. He is not, clearly, making the obvious point that humans and clay pots have different matter; he is making a stronger claim, though it is not clear how strong.7 Minimally, the claim is that commonality among causes requires common features, such as we find among individuals of the same form—​but when we move past such cases it is correspondingly less clear that we have the right sort of commonality between features. Aristotle does not draw a precise boundary between the kinds of thing that can have precisely the same causes and those that cannot, whether or not he thinks it is possible to draw one in principle.

5 “And because of this the causes of all things are the same, since without substance there are no affections or changes. Furthermore, these will probably be soul and body, or mind and desire and body” (1071a1–​2); but this is immediately followed by the point just noted about actuality and potentiality, so even here he seems immediately to undercut the thought that there is a single kind of thing that constitutes the ontological basis for everything else. 6 The import of this passage is especially disputed, since it is the one in which Aristotle seems most clearly to commit to the existence of forms for individuals. 7 For a clear discussion of the passage, see Judson 2019, commentary ad loc.

The Realist Challenge  99 Elsewhere, he argues that under certain conditions, structurally and functionally similar parts of animals are only analogously the same for different kinds, such as human bone and fish-​spine as material causes.8 Nevertheless, some features do have common causes across different species or kinds—​ human and bovine bones are not merely analogous, for example. Overall, and in other works, Aristotle seems to think that to some extent at least this sort of metaphysical pluralism is a case-​by-​case matter: among mammals, for example, some features will be common and have common causes which should be cited as such, while other features will be species-​relative.9 Thus, his metaphysical pluralism extends to entities, properties, and relations between causes and effects, such that occupants of the various causal roles are only the same insofar as they are analogously related to their effects. Nonetheless, the limits on common causes are not drawn a priori or extended all the way down to each determinate (infima) species, but appear rather to be case-​specific and perhaps must be discovered by empirical investigation. This claim about analogical similarity is helpful insofar as it helps determine the overall shape of Aristotle’s approach to concrete questions about how causes relate to effects, but it does not tell us how he can answer such questions themselves. To see how he can, we must first clarify these questions and the types of answer we are entitled to expect. After all, there are a great number of questions and controversies that fall roughly under the heading of “metaphysical relationships between causes and effects,” some of which we should expect Aristotle to be able to answer, and some of which we might not. After clarifying (in the next section) the questions that I think are most important with respect to the lines of argument I have been pursuing here, I will then focus on two factors which combine to determine Aristotle’s answers: one related to matters of essence and definition, and one related to what I call the causal profile of a given explanandum. This approach may seem somewhat indirect, but it is necessary in order to assess his philosophical position, and, as I will show in § 7.5, we will also be in a position, as a result, to answer or re-​orient some persistent questions and controversies that have arisen about causality on Aristotle’s view.

8 See, e.g., Hist. An. I 1, 486b17–​22; PA I 4, 644b8–​15. On analogy in Aristotle’s biology, see Pellegrin 1986; Wilson 1997; and Henry 2014. 9 See PA I 4, 644a23–​b7.

100  Causality and Causal Explanation in Aristotle

5.2.  Clarifying the Question Someone might argue, in fact, that we should not expect much of an answer at all from Aristotle to questions about the metaphysics of causation. Since he thinks we can give an account of the objects of causal explanation without special metaphysics, perhaps we should not expect him to make any more determinate claims about types of entities or relations involved, or even expect him to reject the demand for such an account. His empiricist and “particularist” attitude sometimes suggests, after all, that we should not look for general accounts of such things, which tend to be only speciously informative, but rather give case-​by-​case answers. So perhaps here, too, he would argue for a case-​by-​case approach. Alternatively, he might maintain a kind of agnosticism, or even a stronger type of “anti-​metaphysical” view. If his anti-​ reductionism is in the spirit of Butler’s dictum that “Every thing is what it is and not another thing,” perhaps Aristotle should simply reject the idea that causal explanations need the kind of grounding we look for when we ask how causes relate to their effects.10 A further obstacle is that typical modern approaches follow a pattern which it seems Aristotle cannot: on standard modern approaches, we give an account of causal relations by specifying the category and number of relata (usually events or states of affairs), and the nature of the relation between them (difference-​making, probability-​raising, influence, nomological necessitation, or mark-​transmission, to name the most prominent).11 Such an approach fits well with a reductionist account but also tends to go along with a uniformity assumption: there is one relationship to be captured, the same in all instances where some C causes some E, and the task is to determine whether that relationship is to be analyzed in terms of counterfactuals, difference-​making, transmission, nomological relations, or something else. And if Aristotle does not think that causality is metaphysically uniform even within each mode, it would seem he cannot do this.

10 Butler, Preface (13). Indeed, among recent scholars there is considerable debate about the relationship between Aristotle’s empirical inquiries and his more general theoretical commitments, including his metaphysics, with some arguing that his empirical work closely reflects his metaphysics, others that there is great influence in the other direction, and still others (Bolton 2010) that the two domains are simply and starkly independent. 11 Difference-​making is often taken to cover a variety of accounts, including probability-​raising (e.g., Suppes 1970) and (counterfactual) influence accounts (e.g., Lewis 2000); Dretske 1977, Tooley 1977, and Armstrong 1983 all argue for a nomological necessitation account; process or mark-​ transmission accounts are given by Salmon 1984 and 1997, and Dowe 2000.

The Realist Challenge  101 In general, I do not think he takes up any of these anti-​metaphysical or agnostic attitudes, or that he can: his criticisms of his predecessors are often claims that they gave incorrect accounts of the metaphysical relationships between causes and what they cause, not that they were wrong to give any such accounts. And as we shall see, though he does not raise the question in an explicit way as I have here, he does at various points attempt to work out for distinct types of case how causes relate to their effects. It is true that the modern relata/​relation approach looks unpromising, since Aristotle would not give a single category for causes and effects, and seems to deny that there is one type of relationship that holds even between, for example, efficient causes and their effects. However, while many of the philosophical controversies centering on the metaphysics of causation have played out in the shadow of Hume’s famous critique, these controversies (and indeed the Humean critique itself) arise out of some more basic philosophical questions about causation and causal explanation, to which Aristotle is also sensitive. Indeed, what probably accounts for the enduring influence of Hume’s critique is that, despite its peculiarities, it crystallizes some basic worries about causation that arise for any serious attempt to understand it. We can get a better grip on what demands are placed on Aristotle’s metaphysical pluralism, then, if we understand the kinds of problem that seem to arise from taking causation seriously. I think that three properties especially are at the source of many of the controversies, and that they are all properties that Aristotle takes seriously as well. To be a realist about causation is, in some sense, to accept that there are genuine, explanatory connections between discrete elements of the natural world. If it turned out that some form of ontological monism were true, for example, we would have grounds for saying that what appeared to be cause-​ effect relations were really only earlier and later states of some single thing, and hence that the appearances were radically mistaken. Aristotle is aware, similarly, that if Eleatic monism, as he interprets it, were true, natural science would have no place to start (Phys. I 2, 184b24–​185a14). Further, he is clearly aware of the Academic motivations for introducing separate forms, and he makes the distinction we have noted earlier between things that do not have causes other than themselves and those that do; in doing so, he clearly indicates a view that in general, except for basic principles, the objects of scientific explanation are not self-​explanatory.12 So the notion of explanatory 12 The point is raised clearly in Phys. VIII 4–​5, e.g. 254b7–​33. Waterlow [Broadie] 1988 raises the issue of discreteness in several places (42, 162, 165).

102  Causality and Causal Explanation in Aristotle power seems to require some kind of discreteness if it is to apply to elements of the natural world, and Aristotle is aware of this. Discreteness, in turn, seems to imply a kind of contingent relationship, and it is tempting to argue from discreteness to existential independence. Indeed, it seems that causal explanation deals mainly with contingent happenings in the natural world—​what Hume calls matters of fact.13 To the extent that something can be wholly explained as a matter of necessity, at least, one is tempted to argue that it is not primarily to be explained causally.14 Aristotle acknowledges this principle as well, insofar as he thinks that the domain of perceptible, natural entities is precisely the domain in which what occurs is contingent: it is the domain of “what may be or not be.”15 On the other hand, however, the demand that causes have explanatory power with respect to their effects seems to require that the connections between them be in some sense non-​accidental, for the realist. They are not mere correlations, and the cause has some sort of priority over the effect, determining what happens. There are a variety of non-​accidental connections that might be available: on modern views some notion of necessity or laws of nature is often assumed to be at issue, though some accounts appeal to notions of “intrinsicality” (though not in the sense of ‘kath’hauto’).16 Aristotle’s distinction between intrinsic (kath’hauto) and co-​incidental causes is clearly meant to satisfy this demand.17 But then, to the extent that the relationship seems to be genuinely non-​ accidental, it also seems to lack contingency, especially if we are tempted to gloss non-​accidentality as a kind of necessity. And if causes somehow necessitate their effects, then the nature of their existential independence, and thus discreteness, is called back into question. In one direction, then, explanatory power seems to entail discreteness and therefore contingency, but in the other it seems to entail non-​accidentality of a sort which undercuts contingency, and perhaps ultimately discreteness as well. And Aristotle seems to accept all of these apparent features of causality.

13 See Treatise I.III.IV, Enquiry 1.4. 14 In recent literature this is suggested by distinguishing natural necessity from other, stronger grades; see Lange 2016 for an account of (non-​causal) explanations by constraint, i.e., by a mode of necessity stronger than natural necessity, and especially pp. 73–​86. 15 Met. VII 7, 1032a12–​22. 16 Most accounts appeal to necessity as a way of distinguishing causal (“law-​like”) regularities from accidental ones. For intrinsicality in recent work, see Menzies 1999 and Hall 2004b. 17 See especially Met. VI 2, 1026b27–​1027a28.

The Realist Challenge  103 It is easy to see from just this much the eventual source of the Humean critique. If we make causes and effects too discrete, the explanatory relation seems strained—​indeed, this is part of Aristotle’s critique of Platonic Forms as causes.18 If we make the explanatory connection too tight, we run the risk of losing discreteness or encouraging the suspicion that the relationship is not a causal one, but something much more intimate and perhaps implausibly strong (bordering on identity), eventually courting the thought that in fact nothing that happens could have been otherwise, or that what we ordinarily take to be causal relations cannot really meet the standards being applied.19 It is as though causal relations, to satisfy the roles they are supposed to play, must be necessary but not too necessary, contingent but not too contingent, and involve entities that are discrete but not too discrete. No wonder Hume was suspicious. The tensions among these criteria sometimes come to the surface for Plato and Aristotle as disagreements about whether something counts as a cause or a mere necessary or triggering condition. Famously, in the Phaedo, Socrates accuses the materialists of confusing causes with things without which a cause cannot act as such (99b2–​4), while in GC II 9 Aristotle levels a similar accusation against Platonic Forms as efficient causes (335b18–​24).20 At the same time, he thinks that the Academics are mistaken in their view of matter, failing to appreciate its being an auxiliary cause (sunaition)—​something that is not wholly indeterminate, even if, qua matter, it is essentially passive (Phys. I 9, 192a3–​14). These are both ways in which the tension between discreteness and explanatory power is at work, since they turn on concerns about whether what has explanatory power is too independent of what it explains, or not independent enough. And, of course, we have already seen some ways in which he criticizes his predecessors for making the relationship between a cause and effect co-​incidental (as in reductionist approaches to natural teleology).21 There are several ways in which philosophers have negotiated these apparently competing concerns. Plato, roughly speaking, divides them, placing 18 Enquiry 4.1; the argument against necessary connections between discrete entities has a long history prior to Hume in medieval and early modern philosophy—​see Nadler 1996, and cf. Lewis 1986 for a recent application of a no-​necessary-​connection argument in the same spirit. 19 These worries are, of course, vividly brought out in continental rationalist views and the debates they occasioned, such as those of Descartes, Leibniz, and Malebranche, who posit strong forms of necessitation or “containment” relation between cause and effect. For a sustained account of Descartes’s view of causation and its scholastic background, see Schmaltz 2008. 20 This, at any rate, I take to be the upshot of the argument, discussed earlier (p. 48). 21 See §§ 2.2 and 4.1.

104  Causality and Causal Explanation in Aristotle non-​accidentality among intelligible Forms, which are what they are “themselves by themselves,” while observable, discrete particulars come to participate in them, evidently on a contingent and temporary basis.22 Hume begins with discrete observables and finds only contingent regularity; non-​ accidentality, in the form of an unobservable necessary connection, he places on the side of the observing subject, with famously skeptical results.23 Kant, like Hume, posits a kind of necessity on the side of the experiencing subject, but without, he thinks, the attendant skeptical implications, because of the transcendental status of the pure concepts of the understanding.24 Aristotle would add to this burden, of course, a kind of epistemological optimism, to the effect that causal relations are themselves intelligible, and intelligible in such a way that grasping them produces understanding of a legitimate and even profound sort. This requirement adds further tension, since it is not obvious how knowing about something discrete from and contingently related to a target object will help us understand it in any profound sense. Aristotle, I take it, wishes to defend a metaphysically robust, epistemologically optimistic realism along these lines: there are genuine, non-​accidental, but nonetheless contingent connections between discrete elements of reality, which we are capable of understanding in a strong sense. How to resolve these tensions in the metaphysical account of how causes relate to what they cause is thus a burden we should expect his account of causation to attempt to discharge, as with any metaphysically robust view. How they are to be further reconciled with our ability to have robust knowledge of them is a question we should expect any epistemologically optimistic view to answer as well. I will address the metaphysical tensions among contingency, discreteness, and non-​accidentality in this part; in Part III I will turn to epistemological questions.

22 Recent views which count as broadly Platonist, such as the Dretske-​Tooley-​Armstrong account, similarly posit nomological necessitation relations between discrete universals, contingently instantiated by discrete observables. 23 By this I mean only that he claims that any such connection there might be is located in the mental operations of the observer; as it turns out, famously, this is only “custom or habit” (Enquiry 5.4). I am here setting aside debates about the so-​called New Hume, and whether he actually countenanced some form of causal realism; see Read and Richman 2008 for an assessment. 24 For recent treatments of these views and their modern descendants, see references given earlier, p. 3–4, n. 4. Most neo-​Humean views posit more robust modal relations among discrete observable events.

6 Causes, Kinds, and Transformations 6.1.  From Privileged Entities to Intrinsic Causes An obvious place to begin is to ask whether and how Aristotle’s theory of causality intersects with his ontology or his general theories about what there is, especially his distinctions among categories of being. Though Aristotle does not place causes into any specific category, his account of causality in nature does intersect explicitly with his account of ontology on the side of explananda: a small number of clear and important distinctions seem to govern Aristotle’s conception of what kinds of phenomena admit of genuine causal explanations, and these are rooted in his categorial distinctions. This approach makes sense, insofar as natural science studies being qua subject to change, and Aristotle frames his accounts of change and transformation—​ natural or not—​in terms of the categories of substance, quantity, quality, and place.1 Within the broad class of things and their changes—​broadly construed in ways that will be refined herein—​Aristotle draws the further distinction between those things and changes that have intrinsic causes and those that do not. Between Aristotle’s categorial ontology, his accounts of change, and his distinction between intrinsic and co-​incidental causes, then, he delimits a reasonably compact array of phenomena which are subject to genuine causal explanation. The categorial distinctions are perhaps the most straightforward. The broad class of things that are subject to the four sorts of genuine transformation through intrinsic causes, and so are subject to genuine causal explanation, is then further divided along several lines. The first distinction is between things that are “by nature” (ta phusika, phusei, etc.) and things that are not—​products of human activity such as crafts, teaching, and rational action, as well as co-​incidental phenomena.2

1 See Phys. II 1, 192b14; V 2, 226a23–​b9; VIII 7, 260a27; DC IV 3, 310a23; GC I 4, 319b31–​20a2. 2 See canonically Phys. II 1, 192b8–​32; cf. Met VII 7, 1032a13ff., EN VI 4, 1140a1f.

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0007

106  Causality and Causal Explanation in Aristotle The status of craft requires some clarification here, though I will discuss it more fully later (§ 11.2). Although it is clear that in Phys. II Aristotle is preoccupied with justifying the status of natural-​ scientific explanation, it is also clear that artifacts and their interactions (and the whole domain of human expertise in general) are unqualified examples of causality. This point is important for several reasons, and it is sometimes not appreciated in ways that cause confusion, because of the tendency to focus narrowly on the case of natural substances like organisms. Aristotle does indeed deny that artifacts like statues are substances in an unqualified sense.3 However, this is sometimes taken to imply, or is not distinguished from, the notion that the causes of artifacts are not causes in exactly the same sense or to the same degree as the causes of natural substances, which I think is incorrect. Aristotle gives us no reason to think that sculpting or building or giving medicine is only a qualified instance of efficient causation, for example, and this goes for the other modes as well, however much it may be true that statues and houses are only substances in a qualified sense at best. Indeed, he often goes out of his way to say that in these respects, causality as it relates to crafts is exactly the same as what we examine in nature.4 To the extent, then, that we describe Aristotle as using crafts and artifacts as “models” for causality in nature, we must be careful, as there are different sorts of models and different ways of using them, and he uses crafts in relation to multiple targets.5 With respect to natural substances, artifacts are plausibly to be considered models in the sense of providing a well-​understood phenomenon which is similar enough to the target for an inquirer to be able to make good inferences about the target on the basis of the model, but which is not an example of the target phenomenon. With respect to causality, however, crafts and artifacts are models only in the sense of being salient and well-​understood examples, such that at least some of what we learn by looking at the model can be applied directly and without qualification to the target phenomenon. The only distinction Aristotle draws that would count

3 Witt 2015 contests this, but it is the received view, especially on the basis of Met. VII 17, 1041b29, VIII 2, 1043a4–​12, and VIII 3, 1043b21. 4 See Mete. IV 3, 381a9–​12, b3–​9; PA I 1, 639b15; and especially Phys. II 8, discussed in § 11.2. 5 For some useful distinctions between different notions of scientific model, see Camp 2020, who distinguishes especially between models as frames, as fictions, as idealizations, as analogues, and as “exemplifications,” i.e., what I call here salient examples.

Causes, Kinds, and Transformations  107 as a distinction between causes “strictly speaking” and causes “not strictly speaking” is that between intrinsic and co-​incidental causes.6 Because Aristotle also attempts to explain the nature of substance in light of his understanding of causes, however, these two ways of using crafts and artifacts as models intersect. This makes the relationship between craft and nature more complicated, and so we cannot apply everything we learn about, say, the formal and material causes of sculptures to natural substances, since artifacts are only analogous to substances. (Moreover, the metaphysical pluralism to which I think Aristotle is committed blocks this sort of inference anyway.) Nevertheless, Aristotle thinks that we can learn directly about intrinsic causality as such by looking at artifacts, since they involve unqualified instances of intrinsic causality. Within the class of natural things, there are further important distinctions. In his list at the beginning of Phys. II 1 (192b9–​11), he includes animals and their parts, plants, and the simple bodies (earth, fire, air, water)—​these are all also on the list of apparent substances in Met. VII 2 1028b8–​13.7 Since natural science is about nature, however, and nature is an intrinsic cause of change (192b21–​4), the things that are “in accordance with nature” (kata phusin) include not just natural substances but also “whatever belongs to them intrinsically” (192b35), such as their natural motions (e.g., going up for fire, 192b35–​193a1). This encompasses, it seems, what Phys. II 3 lays down at the outset as the scope and reason for introducing the four causes to begin with: to understand generation, destruction, and every kind of natural transformation (194b20–​2). And as we have seen, besides generation and destruction there are three kinds of canonical genuine transformation, which are changes (kinêseis) properly speaking: alteration (change in quality), increase/​ decrease (change in quantity), and locomotion (change in place). So Aristotle’s list of genuine causal explananda so far includes natural substances, natural transformations of the four canonical types, craft productions, and other results of rational productive activity. The distinction between intrinsic and co-​incidental causality cuts across all of these types of explananda. It, works, in fact, in both directions: something may have a variety of effects, but only be an intrinsic cause of some 6 See Graham 1987 for an attempt to turn craft into not just a clear case but a theoretical model in a much more robust sense, as somehow conceptually essential to the distinctions themselves, which I do not think works. 7 Though parts and elements are not, as it seems, to be counted as genuine substances according to Met. VII 16, 1040b5–​10; cf. Met. VIII 3 1043b21–​23.

108  Causality and Causal Explanation in Aristotle of them; conversely, if something is or comes to be F, some, all, or perhaps even none of its causes will be intrinsic causes of its being or becoming F—​ that is, responsible for its being F the way a sculptor causes a statue “not in accordance with anything except insofar as it is” a statue. Thus, a sculptor’s sculptural expertise is only an intrinsic cause of sculptures, but it may be a co-​incidental cause of other things, such as fame or wealth or a shortage of bronze, while if a sick person gets cured by eating lots of pastry (to take Aristotle’s example of co-​incidence from Met. VI 2, 1027a3), his becoming healthy is not intrinsically caused by what brings it about, in at least two important ways: neither his decision to eat the pastry nor the expertise by which it was produced are intrinsically causes of something’s coming to be healthy. The distinctions Aristotle draws in II 3, including this one, will be discussed more fully later. Here we may note that the difference between intrinsic and co-​incidental causality is sometimes, but not always, a matter of aspect or description. Thus, when the pastry chef makes something healthy because he is also a doctor deploying his medical expertise, the healthy food has an intrinsic efficient cause, which is properly picked out by referring to the person’s medical knowledge rather than his baking skill, though for various reasons we might pick out the cause only co-​incidentally, for example, as a pastry chef or as a person.8 In contrast, Aristotle thinks that some things that do occur, and occur regularly, do not have intrinsic causes of all types, even though they may have causes of those types. The details of his discussion of luck and chance in Phys. II 4–​6 are not always clear, but in general he recognizes a broad class of occurrences and entities which have efficient causes but not intrinsic efficient causes. A desire to see the festival at the marketplace is an intrinsic cause of coming to the marketplace, and where this results in getting one’s money back from a debtor it seems to be Aristotle’s view that this interaction has an efficient cause—​coming to the marketplace out of a desire to see the festival there—​but not an intrinsic efficient cause. This is an irregular occurrence, but there are also regularly occurring phenomena, such as spontaneously generated animals, which have efficient causes but not intrinsic (kath’hauto) efficient causes: they arise from the 8 Similarly, when Aristotle says that the man, Polycleites, is only co-​incidentally the cause of the statue, this is normally, and I think rightly, read as appealing to the fact that qua man, i.e., a male human animal, Polycleites would only be an intrinsic cause of things and activities intrinsically related to his being human, such as producing another human being. So the sculpture, qua sculpture, has an intrinsic efficient cause, which may be picked out either as such or co-​incidentally, with reference to a property or nature of the same thing that is, by virtue of one of its aspects or properties, its intrinsic cause.

Causes, Kinds, and Transformations  109 interactions of basic powers of non-​living things on material which is neither living nor derived from living things, but yields living things nonetheless because of a confluence of circumstances which is peculiar relative to certain norms of nature, despite being common.9 But the intrinsic effects of such things as heat on their subjects are just material changes like changes in temperature and moisture: the active powers of heat and cold act intrinsically on the passive powers of wet and dry.10 Thus, in these cases, unlike that of the baking doctor, we cannot arrive at an intrinsic cause of the phenomenon in question by picking out a different aspect of something named as a co-​ incidental cause, because there is none. Such cases are not restricted to rational or biological activity. Aristotle seems to think that while lunar eclipses have intrinsic (kath’hauto) efficient causes, which indeed must be cited in their appropriate definition (about which more below), they do not have intrinsic material causes—​he says, at any rate, that “Nor is there matter for those things that exist by nature, but are not substances; rather, the substance is the subject. For example, what is the cause of the eclipse—​what is its matter? There is none; rather, the moon is what undergoes [the loss of light]” (Met. VIII 4, 1044b8–​11). Aristotle’s point may be either that (a) there are no special features of the moon by which it is susceptible to eclipse, because any body whatsoever would suffer deprivation of light if another body were interposed (though this makes it seem odd that “interposition of the Earth” is named as the intrinsic efficient cause of eclipses), or that (b) being eclipsed is only a co-​incidental feature of the Moon—​the Moon itself undergoes no real change when eclipsed but just falls into the Earth’s shadow—​so there is nothing strictly speaking to which the darkening applies the way a property or change inheres or occurs in a subject.11 In any case, something may be a cause of F either intrinsically or co-​ incidentally, and something may be F in virtue of intrinsic or coincidental causes. Those things that admit of genuinely illuminating causal explanations 9 For a substantive discussion of the phenomenon as Aristotle understood it and its problems, see Lennox 1982 and Gotthelf 1989. 10 See especially GC II 2, 329b24–​30; Mete. IV 1, 378b10–​26; IV 8 384b24–​30; and compare IV 12 390b2–​14. Similarly, hybrid animals such as mules are the result of interbreeding between animals that intrinsically generate after their own kind but also can regularly produce crosses (extensively discussed in GA II 7, 746a29ff.). 11 The options are not incompatible. See Code 2015 for discussion of this example and the relevantly similar case of sleep. See also Met. VIII 5, especially 1044b27–​29, where Aristotle connects something’s having matter to its being susceptible to genuine generation and change in the relevant respect.

110  Causality and Causal Explanation in Aristotle are those that have intrinsic causes, Aristotle thinks, and indeed he argues in Met. VI that there can be no science (epistêmê) of what is co-​incidental. This view is to some extent a reflection of common ground with the Socratic-​ Platonic view that in order to understand something we must understand what it is in its own right, but this also represents a break with it in two ways: (a) understanding what pertains to something intrinsically or “qua F” is, on this view, not just a matter of understanding F-​ness itself but of the thing that is F, and (b) the intrinsic causes of something’s being F are not limited to the formal relationship between the thing and its F-​ness.12 Taking all these distinctions together, the following basic (but perhaps non-​exhaustive) list of genuine causal explananda can be extracted from the texts we have seen. They are broadly divided into “static” and “transformational” phenomena, where ‘transformational’ just refers to the four genuine kinds of transformation. This yields the oddity that what Aristotle considers activities or actualities (energeiai), such as thinking or dancing, are here counted as static, insofar as, on Aristotle’s view, an activity is not an intrinsic change to an agent but is rather an exercise of capacities which are already complete.13 Since these are all presented as candidates for causal explanation, I take it that they all have intrinsic causes in at least some of the four modes; but we should not assume that they all have intrinsic causes in all four modes. Transformational phenomena (both natural and artificial):

• • • •

Generation and destruction Increase and decrease (quantitative change) Alteration (qualitative change) Locomotion (change in place)

Static phenomena: • Substances (including paradigmatically living things, and provisionally other natural kinds like the elements) 12 The view also relegates the explanation of one-​off events to the domain of special and derivative cases, which means that many of the cases which have driven recent theoretical work on causation, such as singular events and cases of trumping or double prevention, will play a different methodological role relative to his account. 13 This, at any rate, is how I understand the kind of activity (energeia) that exhibits an “internal end,” which features most prominently in Met. IX, especially ­chapters 6 and 8; see Makin 2006 for an overview and commentary. I translate “energeia” as either activity or actuality depending on the context; where it needs to be distinguished from the closely related and sometimes interchangeable “entelecheia” I provide the terms in parentheses. See p. 174 n. 23.

Causes, Kinds, and Transformations  111

• Parts of substances • States or attributes of substances (quantitative, qualitative, local) • Activities of substances • Artifacts • Parts of artifacts • States of artifacts • Activities of artifacts • Composite wholes, whether natural or artificial, including especially natural compounds of the primary elements, which are not substances or fully formed artifacts in the strict sense.14

The two categories are linked, of course, in that the dynamic phenomena are in general undergone by substances and artifacts or their parts or compounds—​including the generation and destruction of living things, of the elements (via their inter-​transformation), and of artifacts, as well as the regular behavior of elemental compounds (as described in the Meteorology), of “uniform” bodies that compose animal parts, the various properties and features of complex substances, and their complex patterns of activity. All of these, though, are essentially connected to transformation. Almost all of them involve “coming-​to-​be” in the two senses Aristotle distinguishes, either qualified or unqualified coming-​to-​be (i.e., either coming to exist as a certain kind of thing or coming to bear some property through change).15 Schematically, Aristotle ultimately treats both of these as “coming-​to-​be F,” since anything that comes to be full-​stop comes to be something or other (human, oak tree, clay, and so on). The main exceptions are activities, since these are not changes to the intrinsic features of anything, but rather deployments or expressions of the natures things already have—​but these natures are again, of course, the results of transformations. In sum, genuine causal explanations apply principally to instances of natural or artificial kinds, their properties, their generation and destruction, the changes they undergo, whether natural or artificial, and the ways in which they behave. As general groupings, labels are needed, and I shall label them Transformations, Beings, and Activities. Beings include entities as well as states of affairs: that is, having various attributes—​magnitudes, qualities,

14 Examples would be the various metals and other uniform stuffs formed from the “exhalations” described in Mete. I–​III, and whose propensities are discussed in Mete. IV; see especially ­chapters 6–​8. 15 For the canonical distinction see Phys. I 7, 189b32–​190a31.

112  Causality and Causal Explanation in Aristotle and the like. Activities include primarily those things that Aristotle clearly distinguishes from simply having a property or a capacity which is essentially related to change; since this is a somewhat controversial category (in view especially of its connection to some of Aristotle’s most fundamental views about matters of basic ontology and psychological activity), to the extent that I discuss it I will focus on comparatively clear cases such as exercising life functions by living beings and their parts (rather than, say, the cognitive activities which have been the source of enduring controversy). Aristotle, then, despite his metaphysical pluralism, has a reasonably precise and compact way of specifying the objects of genuine causal explanation, one which actually recognizes a kind of ontological privilege with respect to causality, but on the side of effects rather than causes. Genuine causal explananda are the transformations, beings, and activities of those kinds that have their causes intrinsically—​to the extent that they do, since not all natural things have all of their causes intrinsically.

6.2.  Essentialism and Kinds of Natural Change There is a well-​established interpretation to the effect that Aristotle’s essentialism includes the view that natural kinds have “real definitions,” by which is meant, roughly, that there are features of a kind which correspond to its essence, and which may be different from those by which it is initially picked out as a kind.16 This view seems to involve a broad commitment to the idea that we explain any particular phenomenon by reference to an essence-​specifying definition, if it is an instance of the sort of thing that has an essence—​paradigmatically, a substance like a living being. Aristotle also closely connects questions about what things are with questions about why they are, such that specifying a thing’s essence is ultimately a matter of specifying its causes.17 (In this he follows Plato at least roughly, insofar as Platonic Forms are causes and are what we aim to grasp in answering “What is F-​ness?” questions.)

16 This is, I think, an uncontroversial way of putting it; that Aristotle takes natural kinds to have essences is, of course, undisputed, but the nature of the difference between an account that picks out a thing’s essence and what I here call its “pre-​theoretical” aspect is very much disputed; some of the disputes are discussed next. For an especially important and influential account of Aristotle’s essentialism, see Charles 2000—​critics of his view on particular points are noted where relevant. 17 Canonically, APo. II 1–​2, concluding with the explicit statement at 90a31–​34.

Causes, Kinds, and Transformations  113 If Aristotle thinks that there are a variety of types of beings, transformations, and activities which have intrinsic causes, then it is reasonable to expect all of these to have causal essence-​specifying definitions, not just beings like substances. I think that Aristotle does hold this broader essentialist view, but a number of confusions arise about what it amounts to, which relate to a wide array of controversies, especially concerning Aristotle’s theories of substance and definition. It will not be possible to work through them all, but it is important to clarify the sense in which Aristotle thinks that these natural regularities, including transformations of various types, are subject to causal essence-​specifying definitions which cite a number of intrinsic causes. In particular, we must be careful how we connect the general notion of an essence (what it is to be something, for anything at all) with the more narrowly metaphysical notions of Aristotelian form (eidos) and “formal cause.” Now, Aristotle often appears to follow Plato rather closely in identifying a thing’s essence with its form, but where this is understood by Aristotle as a unified property or property-​like something that, in his view, “combines” with matter to constitute a perceptible compound being. Indeed, his canonical gloss on the “formal cause” in Phys. II 3 is that it is the “the form, i.e. the paradigm, and this is the account of the essence” (194b26–​7), and in some key passages of his discussion of substance, he seems to assert that form alone is the object of definition.18 On the other hand, as we have seen, Aristotle says in the physical works that the essence-​specifying definitions of natural things include matter, and, indeed, this seems to some extent to be at the core of his commitment to hylomorphism.19 Moreover, in a well-​known passage at the beginning of the De Anima (403a25–​b19), Aristotle seems to claim that psychological phenomena such as anger and other enmattered entities should be defined with reference to all four types of cause, or at least three.20 Though focusing on psychological phenomena, Aristotle’s discussion shows a clear awareness

18 See especially Met. VII 7, 1032b1–​2 and VII 10, 1035b32–​1036a2, as well as M. Frede 1990 and Gill 1989, ch. 4. 19 Phys II 2, 193b32–​194a5. Note that in this passage definability and “separability” are connected to both change and matter in ways that are not entirely clear: it is stated that unlike mathematical entities, the definitions (horoi) of natural things cannot be stated without reference to change; rather, the latter are defined like snub, i.e., with reference to matter, and it is the connection to matter that is taken up. The move from change to matter is made explicit at Met VII 11, 1036b28–​30: “But it is not similar; for an animal is something perceptible, and it is not possible to define it without reference to change, wherefore nor is it possible to define it except as having parts in a certain way.” 20 The description of a correct definition of anger in the passage (at 403a26–​27) includes the efficient cause, but that of a house (403b6–​7) does not.

114  Causality and Causal Explanation in Aristotle of theses and distinctions related to the notion of definition in general, including a distinction between types of definitions proper to a natural scientist (phusikos) as opposed to a “dialectician” (dialektikos), and he raises some of the same points raised in Phys. II 2. Commentators differ about how to integrate these claims, and many tend to give one or the other priority. These differing tendencies have in turn given rise to a variety of controversies over the nature of form and what is supposed to be “included” in an essence-​specifying definition, which are not helped by the fact that Aristotle gives no explicit examples of scientifically accurate definitions for paradigmatic natural kinds such as biological species—​only some toy examples and various statements in the biological works about what is or is not in the substance (“ousia”) of a given species.21 Thus, the nature of Aristotelian essence-​specifying definitions is controversial and in need of some clarification, especially as they apply to natural science and its commitment to hylomorphism, and to causal explanation more generally. One source of these difficulties is that Aristotle’s most sustained discussions of definition and essence across the corpus do not all cohere in a clear way, but contextual differences make it difficult to see whether his remarks involve genuine differences in content. In APo. II 10, in particular, he also distinguishes several different types of definition, and it is not clear exactly how many he wishes to recognize, their precise character, and how they relate to definitions as discussed elsewhere.22 What matters most for our purposes is that Aristotle accepts a general distinction between two ways of “saying what something is.” One is to refer to a thing’s intrinsic causes, which is usually identified as a goal of scientific inquiry, and so we may call it a theoretical or real definition. The other is

21 Two controversies in particular are of note. One pertains to the nature and number of the kinds of definition Aristotle recognizes, including whether he recognizes a kind of “nominal” definition, and whether this represents a distinctive stage of inquiry. The second pertains to the role of matter in definitions and whether Aristotle thinks that the forms of natural things “include matter” or not. On the former see Charles 2000, chs. 1–​2, and criticisms by Bolton 2018, as well as Modrak 2010 and Sedley 2015; cf. Ross 1949, 631. On the latter see M. Frede 1990; Charles 2009; Peramatzis 2011, and criticisms by Malink 2013, as well as Gill 2005 for a useful overview. Burnyeat 2001, 74–​75, points out that at Met. VIII 2, 1043a14–​28, Aristotle accepts three types of definition without privileging or diminishing any of them, and draws the reasonable conclusion that Aristotle’s frequently repeated claims that natural-​scientific definitions must specify both form and matter are not undercut by anything he says about form and definition in Met. VII. 22 For a full treatment of the topic, see Deslauriers 2007. APo. II 8–​10 is a sustained discussion of definition and its relation to demonstration; the question of nominal definition in particular is raised by II 10.

Causes, Kinds, and Transformations  115 to refer more narrowly to a property or form, or discriminating conditions, rather than a thing’s intrinsic causes. Commentators generally agree that this narrow, non-​causal way of saying what something is to available to the non-​ scientist, or at least characteristic of the early stages of scientific inquiry, so that it makes sense to call it a pre-​theoretical or “phenomenal” definition. (The exact nature of this pre-​theoretical stage is controversial, and the controversy extends to whether it is appropriate to call this a ‘nominal’ definition; because I do not think it makes a difference with respect to the points I wish to make, I will use the more generic terminology.) The fact that a thing’s essence is identified with its cause or causes should therefore be distinguished from the claim that one mode of causal explanation is by reference to a thing’s essence, that is, the claim that the so-​called formal cause is a type of cause. The claim that one mode of causal explanation appeals to a thing’s essence is broader, since one can, Aristotle thinks, cite a thing’s essence as the cause of more than just its being an instance of whatever kind of thing it is. Most notably, essences explain a thing’s “intrinsic accidents,” stock examples of which are a triangle’s having angles summing to 2R, and the ability of essentially rational beings to laugh or learn a language—​ properties which “flow” directly from the essence without being a part of it. By contrast, the causal-​essence claim is narrower and perhaps more tendentious: it states that essences themselves are intelligible, and that in order to give an account of just what it is to be an instance of a kind, one must state a thing’s cause or causes, of whatever sort they are.23 We should also distinguish the claim that in order to understand why something exists or happens, we must cite all of its causes, from the claim that in order to understand what something is, we must cite all of its intrinsic causes. Even someone who rejects all talk of essences can accept the first claim, but the second explicitly commits to some sort of essentialism and is far more controversial. Even for Aristotle, in principle and in practice, these can come apart. As we have already seen, some phenomena, notably co-​incidents, do not even have intrinsic causes, but they can be given causal explanations, while other things may have a full causal explanation, and hence a causal essence, and yet it may also remain open whether all or only some of those causes are included in its essence.

23 It is perhaps not surprising that there are some ways of referring to this sort of explanation which generate confusion, since it is tempting to refer to anything answering to an essence of a thing as its form, as noted earlier.

116  Causality and Causal Explanation in Aristotle What, then, about the overall content of theoretical (i.e., causal) definitions? Aristotle does not appear to lay down restrictions on what can and what cannot be included in a statement of a thing’s essence. But since he thinks (a) that essences are what we give in response to “What is it?” questions, (b) that the answers to “What is it? and “Why is it?” questions converge, and (c) that the question “Why?” is appropriately answered by referring to a thing’s causes, we might conclude that a statement of essence should refer to all of a thing’s intrinsic causes, whether formal, final, efficient, or material. If some things have causally rich essences, then their definitions should cite all of them, but if there are a variety of different causal profiles something might have, then we should expect that the definitions of different sorts of thing will appeal to different types and combination of causes. I think that Aristotle does accept this claim in at least some form: that real definitions should cite all of a thing’s intrinsic causes, and in principle these may include up to four causes in varying combinations. I also think that, as we shall see, Aristotle describes a variety of different profiles in the physical works, for what appear to be causal essence-​specifying definitions of different sorts of phenomena—​so that he also affirms that there is no one template for causal definitions in natural science. Whether he would claim that such definitions are all in the strictest sense specifications of real essences is a difficult matter to judge, which intersects with a nest of thorny textual and philosophical issues that are not directly relevant here, including those mentioned earlier. Nevertheless, I think we can get a clearer appreciation of causal explanation in general, including the natural scientist’s approach to substance, by seeing how this causal essentialism works in a variety of cases, especially non-​substance cases.

6.3.  Pre-​theoretical and Theoretical Accounts of Change If Aristotle applies his causal essentialism as broadly as I have suggested, we should expect to find the distinction between pre-​theoretical and theoretical definitions applied to many different natural phenomena, not just species. I have already cited the well-​known passage from the De Anima concerning definitions of the affections (pathê) of the soul, but since Aristotle’s account of soul is so tightly bound up with his theory of substance, this example might be treated as a part of the scientific inquiry into natural substance. Activities, too, are tightly bound up with substance, since for living beings,

Causes, Kinds, and Transformations  117 Aristotle thinks that understanding what they are as substances involves understanding their activities as well.24 Given the distinctions drawn earlier between Transformations, Beings, and Activities, then, the most important extension of essentialism with respect to natural science would be to transformations, that is, to generation/​destruction and the four types of change. Aristotle does in fact recognize a distinction between pre-​theoretical and causal definitions of transformations, and we find many examples of what look to be causal definitions which substantiate the broad interpretation of essences as including all of a thing’s intrinsic causes. This latter claim, I shall argue, is subject to important refinements, depending on the type of phenomenon in question. If this is correct, one important factor in answering the question of how a thing relates to its causes in general is that it depends on how those causes relate to its essence. A key text in this regard is in the final chapter of Met. VII 17, where Aristotle makes a fresh start in his discussion of substance (ousia), starting from the thought that substance is a kind of principle or cause. He argues that the problem of substance becomes tractable once we recognize that even here we can treat it, as in other inquiries, as a question why something “belongs to” or is predicated of something—​why a subject is some F. When we do so, we see that we will answer the question of a thing’s essence by indicating the cause by which some F applies to some S: Therefore one is inquiring why something belongs to [i.e. is predicated of] something. (That it does belong to it must be clear; for if it is not thus, one is not inquiring about anything.) For example, why does it thunder? Why does noise come to be in the clouds? For this way what is sought is one thing holding of something else. And why are these things, e.g. bricks and stones, a house? It is evident then that one is inquiring after the cause; but this is the essence, to speak in the abstract (logikôs), which for some things is what it is for the sake of—​for example, perhaps for a house or a bed—​while for others it is what first brought about the change; for this is also a cause. But this sort of cause is sought for generation and destruction, whereas the former is also sought with regard to being. (1041a24–​32)

24 This principle is made explicit at Mete. IV 12, 390a10–​13, and it is at work in some of the passages in which Aristotle states that a thing’s formal and final causes are the same or one; these passages are discussed later in § 7.5.

118  Causality and Causal Explanation in Aristotle Aristotle distinguishes here between two ways of speaking about a thing’s essence: a general or abstract (logikôs) way, and another way which differs depending on the explanandum in question. ‘Logikôs’ is often used in contrast to ‘phusikôs’, that is, characteristic of natural science.25 Though Aristotle may mean something broader in this passage, since he aims to be discussing substance in general (albeit beginning with perceptible substance), his claim is nevertheless that a thing’s real definition will cite either a final cause, as in the case of an artifact, or an efficient cause, “in the case of generation and destruction.” These causes are evidently what we cite when we capture an essence not logikôs, that is, in the general or abstract way, but rather in a theoretically appropriate way, by giving an explanatory real definition. This claim will seem surprising if we think of generation and destruction solely with respect to the paradigm substances which are the focus of these middle books of the Met.—​that is, unqualified generation and destruction, since he seems to identify even generated natural substances with their ends or final causes, rather than their efficient causes. However, if the reference to generation and destruction is rather to processes of coming-​to-​be themselves, considered somewhat independently of substance, and is meant to cover all sorts of change, then the contrast makes more sense.26 Certain definable things, such as processes of generation and change, are essentially the actualities of certain types of efficient cause, and so their real definitions must take account of this, whereas other things, including not just comings-​to-​be but also things that exist, are defined in terms of their final causes. This passage is also surprising if we are expecting Aristotle to think that a thing’s essence includes all of its intrinsic causes, since it leaves out matter (contrary to the lesson of Physics II 2, discussed earlier), and seems to leave out form as well, even if form turns out to be the cause we are looking for in the case of substance, as he says. Why are efficient and final causes singled out as non-​“logikôs” causes that answer to the question of a thing’s essence?27 25 The precise nature of the logikôs/​phusikôs distinction is controversial; see Ross 1924, 168, 171, 223; Burnyeat 2001; and Bolton 2009. 26 In general, causal explanation in natural science is explicitly concerned with transformation, as is clearly stated at the beginning of Phys. II 3, 194b18–​22: “we do not think we know each thing until we grasp the Why for each thing (and this is to grasp its primary cause), it is clear that we must also do this concerning generation and destruction, and every natural transformation (metabolê).” That is, our goal in framing the foundations of natural science is to examine nature with a particular focus on the processes of transformation and the whole domain of “becoming,” however important stable beings (i.e., substance) may be for other purposes or for the overall understanding of nature. 27 The passage is surprising enough that Alexander thinks the phrase about speaking “abstractly” is spurious, in response to which Ross 1924 comments: “The doctrine is that the cause of the inherence of a πάθος in a substratum (e.g. of noise in clouds) or of a quality in certain materials . . . is always—​to state the matter abstractly (λογικῶς)—​the τί ἦν εἶναι or definition of the union of substratum and

Causes, Kinds, and Transformations  119 I will return to this question below, but first it is important to see whether and how Aristotle applies a distinction between pre-​theoretical and causal definitions to natural transformations. As I shall argue, his well-​known “definition” of change in Phys. III in fact offers a sort of schema for giving real definitions of changes which cite their efficient and material causes, to which he alludes briefly at the end of III 3. The Physics actually contains two separate discussions of change, both of which purport to be fully general, both of which indeed claim to state “what change is,” and both of which give criteria for defining determinate species of change. The first is in Phys. III 1–​3, and the other is in Phys. V, especially ­chapters 1–​2 and 4–​6. The more well-​known is the one in Phys. III, which contains the well-​known definition of change as “the actuality of what is in potentiality as such” (201a11). Aristotle concludes the discussion in V 1–​2, however, by stating that it has sufficed to make clear “what change and rest are, and how many kinds of transformation (metabolai) and what sorts of change there are” (226b16–​17). The two discussions do not conflict, but they also seem to proceed independently of one another.28 Since each of them presents a general statement about what change is and offers a schema for specifying determinate species of change, we should assume for the moment that they are meant to cohere, and that Aristotle recognizes both general accounts of change and its species as legitimate. We should wonder, then, why Aristotle gives us two such accounts, and how they do cohere. The book V discussion, as I shall argue, bears the marks of a general, “logikôs” discussion, while the book III discussion bears the marks of a natural-​scientific (phusikôs) one.29 Book V discusses change in terms which are entirely congenial to dialectic, and which in fact do not seem to range beyond its tools, which is one πάθος, or of materials and quality. But in some cases this definition expresses the final cause—​e.g., a house is defined as a shelter for living things and goods . . .; in other cases the definition expresses the efficient cause—​e.g. thunder is a noise in the clouds due to, i.e. produced by, the quenching of fire . . . In other words the formal cause is not a distinct cause over and above the final or efficient, but is either of those when considered as forming the definition of the thing in question” (223, emphasis mine). I do not think the last part can be correct as it stands as an interpretation of the passage; my own reading of it follows in Chapter 7. 28 In V 1 (224b11) he appears to refer back to the definition in book III, though the back-​reference is somewhat tenuous: the discussion does not in fact refer to anything specific to the III 1 account, and many commentators think that books III and V were originally parts of different works (see Ross 1936, Introduction, § 1). 29 This suggestion has not been made by commentators as far as I am aware, and so the interpretation here is not a standard one.

120  Causality and Causal Explanation in Aristotle feature many commentators have noted seems to be associated with what Aristotle describes as a “logikôs” way of proceeding.30 Indeed, he introduces a key distinction between ways in which there is or is not an enduring underlying subject for transformations—​yielding our fourfold distinction between generation and destruction, on the one hand, and the three kinds of change in the strict sense, on the other—​by reference to the fact that the very term ‘metabolê’ implies that all transformation is “from something to something” on the grounds that the term contains ‘after’ (meta) as a part, that is, by reference to the word (logos, 225a1–​2). The types of transformation are then divided according to the role of the subject, and whether the “from” and “to” are contradictories or contraries (225a34–​b5), after which Aristotle applies his categorial distinctions to argue that genuine change is only possible in the categories of quantity, quality, and place (V 2). The arguments to exclude change in other categories are mainly focused on the (notorious) arguments against change of change, that is, change which would take place in the categories of action and passion.31 These arguments appear to proceed entirely on the basis of raising problems for the possibility of such change because of the conceptual requirements that change involves a subject and contraries—​for example, he argues that transformation could not grow or alter because transformation is not a subject (225b20–​1). The arguments do not, by contrast, raise questions using concepts peculiar to Aristotle’s physical theory, such as actuality and potentiality, even though one might think that a change in something’s agential capacities would count as change in the category of action—​as when a knife’s blade is dulled. Nor do these chapters present the distinction between the subject and the privation (i.e., the matter) relative to a kind of change, or analyze changes in terms of the qualitative and quantitative properties they must have. They are also all reductio arguments, except for one which concludes that change of change is possible on one reading, but only co-​incidentally (225b22). The discussion in the first two chapters of book V thus seems to indicate that to specify a determinate kind of change is just to specify its subject and the contraries between which the subject transitions, and it proceeds without making any use of the notions of matter or potentiality, which play such a prominent role in Aristotle’s other discussions of change.32 30 See especially Burnyeat 2001, 19–​24. 31 Indeed, the categories of substance and relative are given one sentence each, while time, position (keisthai), and state (hexis) are left out entirely. 32 There is one mention of potentiality (‘kata dunamin’) at 225a22, and one of matter (‘hulê’) at 226a10, but they are peripheral to the argument, and the points do not turn on their special uses as

Causes, Kinds, and Transformations  121 This interpretation is supported by the subsequent discussion in V 4. The explicit topic of V 4 is the unity of change, that is, the conditions under which something may be said to be one single change (227b3ff.). As usual, Aristotle points out that things may be “one” in a variety of ways, and his accounts of these modes of unity are instructive. Ultimately he appears to be concerned with what we might call the identity conditions of individual changes, and he focuses especially on questions like whether a change can be one if it stops and starts, or comes back around to the same starting point (228a2–​12). One of the criteria, however, for a change’s being one is that it be one in form or species (eidos, 227b30). After referring to his division of change into the genera of alteration, increase/​decrease, and locomotion, he says that changes are one in species (eidei) when they are one in genus and are “in an indivisible species” (en atomôi eidei), that is, when their endpoints are contraries that are maximally determinate, such as colors—​every “whitening” is one in species (227b6–​11). Somewhat surprisingly, when Aristotle goes on to contrast being one in species with being unqualifiedly one, he glosses the latter by means of the further criteria of oneness in substance (ousia) and number. These further distinguishing factors, however, are both peculiar to an individual change, rather than further determinations of a type of change: a change is unqualifiedly one if it is one in species, takes place in the same individual thing (Socrates and Coriscus are examples rather than something like ‘body’ or ‘surface’), and takes place in the same time. Thus, by the criteria of Phys. V 4, the specification of the determinate contraries between which something changes is enough to give the most determinate type-​level specification of the change. This would indeed seem to be a natural view: that changes are individuated by their endpoints. But again, this criterion makes no appeal to matter or the determinate capacities of the changing subject.33 It is the kind of definition of types of change one might give on the basis solely of common notions and observable features referring either to a capacity for a determinate sort of change or to the proper subject of change (‘kata dunamin’ is used only to mean “not actually,” and ‘hulê’ is here used as a synonym for “subject”). 33 Charles 1984 thinks that Aristotle is including a notion of capacity in relation to the individual subject, citing 224a28–​30 from the beginning of V 1 (16). However, in that passage Aristotle really only says that changes are different depending on what properties are involved, contrasting getting healthy with getting warmer. Charles follows the Revised Oxford Translation by translating ‘alloiôton,’ ‘hugianton,’ and ‘thermanton’ as ‘capable of alteration/​being restored to health/​heated’; but while these terms do indicate susceptibility or capability in a plain sense, it is too much to take them as implying the robust sense of capacity (i.e., dunamis) that Charles requires.

122  Causality and Causal Explanation in Aristotle of changing subjects. In sum, the discussion of change in Phys. V uses pretty much only the same concepts available to the writer of the Organon and of the “logikôs” passages of Met. VII, and the arguments make no appeal to the concepts peculiar to Phys. I and II or the natural-​scientific works—​that is, they make no appeal to the theoretical understanding of change that is proper to the natural scientist. The discussion of Phys. III proceeds differently, starting with the explicit reminder that this is an inquiry into nature (200b11–​12). Aristotle first frames change in relation to the basic categories, but then, unlike in book V, connects the categories with the notions of form and privation as they relate to change (201a4–​9). Finally, he connects form and privation with the concepts of actuality and potentiality, yielding the statement that change is the actuality of what is in potentiality as such (201a9–​15), which he elucidates with the example of the builder: whenever the buildable as such is in actuality, it is being built, and this is building (201a16–​18).34 Aristotle generalizes this to other changes: “learning, doctoring, rolling, leaping, maturing, and aging” (201a18–​19). Thus, the Phys. III discussion proceeds using the principles peculiar to natural science from the start. After further support and clarification of this claim, Aristotle points out that on this view we must say that the actuality of the agent’s potential to act in fact takes place in the patient on which it acts: that is, the one item, the change in the patient, is both the actuality of the agent’s potential to act and of the patient’s potential to be acted upon.35 He then notes that this view is subject to a “logical” (logikôs) objection (III 3, 202a21–​b5). The basic idea behind the objection is that if the agent actualizes its potentiality and the patient does likewise, and their respective potentialities to be agents and patients are different, there would seem to be two actualities, one for each, and indeed one in each. But this would yield odd consequences: it would seem to follow that the agent suffers the same action that the patient does, or that “though having change it will not change,” 202a30–​31, or that it acts but its action is dissociated from it.36 His response is in essence to state that there is nothing absurd in an agent’s action being located in something else, and I think the implication is clearly enough that the objection only presents a pseudo-​problem, since it deals only 34 The literature on this passage is large; see Gill 1989, ch. 7, for a useful survey and a clear treatment of the problems raised by this account of change. 35 These statements are discussed further later, especially in Chapter 8. 36 For the literature on this puzzle, see references in § 8.3.

Causes, Kinds, and Transformations  123 with implications that seem to follow from ordinary, pre-​theoretical notions of “being an agent,” “acting,” and “changing”—​this is why it is “logikôs.” Once one understands what is really involved when something undergoes changes of which it is capable by means of the action of something else upon it, the problem disappears. The logikôs puzzle is resolved by a natural-​scientific (phusikôs) understanding of how change actually works. Aristotle then states that motion in general and each kind of motion should be defined in this way, as we have seen earlier. That is, we should define “each of the forms of [change]” (tôn eidôn hekaston autês) as the actuality of what is alterable/​increasable/​movable as such (202b23–​26). In what almost looks like an aside, he then states that these definitions will be given more intelligibly (gnôrimôteron, which is the word he uses in distinguishing what is more knowable by nature or without qualification from what is more knowable to us) according to this schema: “the [actuality] of what is capable of acting and being acted upon, as such, both unqualifiedly and again in each case (kath’hekaston), whether housebuilding or doctoring” (202b26–​ 29, my emphasis). In other words, both the agent and the passive subject are to be included in the more intelligible definition of a change, down to its determinate species. If, as I will argue later (and as some commentators also think), “more intelligible” here means “more appropriate to scientific understanding,” then Aristotle is asserting that the real definition of a determinate natural kind of change will include reference to the potentials of the agent and the patient: that is, to the intrinsic efficient and material causes of the change. I think in fact that although he makes the point only briefly, this is exactly Aristotle’s view when it comes to the kinds of basic causal interaction (i.e., “transeunt” change) upon which he seems to be focusing in these chapters. Further, as I shall argue in the next section, he provides many examples fitting this definitional schema in other works, especially the Meteorology, which deals with basic interactions among material compounds, one of which is considered the agent and one of which is the patient, susceptible to such changes in virtue of its particular material features.

6.4.  Real Definitions of Transeunt Interactions The Meteorology as a whole discusses the material and efficient causes of natural phenomena, with the first three books focusing on “meteôra”

124  Causality and Causal Explanation in Aristotle properly speaking, that is, atmospheric phenomena and related geological phenomena, all of which are associated with the motions and changes of two basic material principles, the so-​called moist and dry exhalations.37 Book IV focuses more narrowly on the interactions among material compounds (made up of fire, air, water, and earth), characterized by the active powers (dunameis) of hot and cold and the passive powers of moisture and dryness, these basic properties being themselves the primary (formal) causes of the four basic elements (IV 1, 378b10–​13). The active powers “determine, unite, and transform both things of the same kind and things that are not of the same kind, moistening, drying, hardening, and softening them” (378b15–​ 18), and things with the passive potentialities undergo these things. Thus, more generally, these powers or qualities constitute the efficient and material causes of unqualified generation and natural change (IV 1, 378b28–​34ff.).38 The book provides accounts of generation and destruction for these sorts of compounds, as well as a whole series of causal interactions, in terms of the functioning of these basic properties, especially “concoction” (pepsis), which Aristotle takes broadly to be a generic form of generation by the action of heat upon a patient.39 Unqualified generation of this sort is characterized in general as follows: a transformation by these capacities, whenever they stand in a certain proportion (logon), out of the underlying matter for each nature; and these [i.e., the different underlying matters for each nature] are the passive capacities described. And hot and cold generate by prevailing over the matter; but whenever they do not prevail, there is parboiling and inconcoction in parts. But the contrary to unqualified generation that is most common is putrefaction; for every natural destruction proceeds along this route, such as old age and drying up. (378b31–​379a5)

37 See especially Mete. I 4, 341b5–​12 and II 3, 357b24 for the general claims; cf. Wilson 2013, who focuses on the first three books of the Mete., and who also claims that the work as a whole aims at presenting definitions of natural phenomena. 38 “Unqualified generation and natural transformation is the function of these powers, as is the opposite, natural destruction” (Mete. IV 1, 378b28–​30); that Aristotle has in mind efficient and material causation is clear from the context and the analyses that follow. 39 See Lloyd 1996, ch. 4, for a detailed discussion of the varieties of concoction, and the manner in which Aristotle extends the term to cover a broad range of phenomena. Lloyd also raises concerns about the nature of Aristotle’s account of concoction, especially its relation to the ideal of scientific definition and demonstration laid out in the APo., some of which I address later.

Causes, Kinds, and Transformations  125 In general, that is, generation is the action of hot and cold in a certain proportion upon subjects bearing the passive properties of moist and dry in a certain proportion. After some more detail, especially concerning the conditions under which putrefaction (sêpsis, i.e., destruction) takes place, we are told that the preceding is “what generation and destruction are,” using the “ti esti” phrase which is in general characteristic of some sort of definitional statement.40 The subsequent chapter also presents the aim as giving “ti esti” statements of basic interactions, specifically the types (eidê) of things brought about by these powers from subjects that are already constituted a certain way by nature.41 These are concoction and its species, such as ripening, boiling, and broiling (pepansis, hepsêsis, optêsis). Thus, specifying what each of these is amounts to specifying the precise features of both the passive subject (the way in which it is constituted) and the complementary features of the agent by which it is able to bring about a specific sort of transformation. In general, that is: “Concoction is the completion (teleiôsis) by the natural and proper heat (hupo tou phusikou kai oikeiou thermou) from corresponding patients (pathetikôn); these are the matter proper to each thing” (IV 2, 379b18–​20). Here we should note both the presence of the efficient cause (natural and proper heat) and the material cause, with the “out of X” phrase used in the canonical definition of matter, and that the statement as a whole is presented as a definition: Aristotle is not simply describing phenomena and counting this as saying “what things are,” but attempting to give concise statements of the form “X is _​_​_​” where the right side names determinate efficient and material conditions of the agent and patient, out of which a given property or kind of thing is produced in the patient.42 Indeed, Aristotle recapitulates many of his statements in this book as having stated both what and why they are, recalling the APo. identification of answers to what-​it-​is and why-​it-​is questions. For example, following the

40 “So then, what generation is, and what destruction is, has been said” (IV 1, 379b8–​9). 41 He says: “Let us say what each of them is” (379b17–​18). 42 Lloyd 1996, pp. 95ff., raises worries about the adequacy of Aristotle’s statements about concoction and its component terms as definitions, both in general and in terms of Aristotle’s own criteria. One worry is that his characterizations are too indeterminate to count as genuine definitions of the phenomena they are supposed to render, and that Aristotle is not attentive to questions of when his definitions must be specific and when they must be more broadly applicable (e.g., when a given phenomenon is or is not the same across different kinds). However, some of Lloyd’s worries, especially the more general ones about the type of definition at issue and its suitability for scientific explanation, may be blunted by recognizing the way in which these definitions correspond to the schema for giving causal definitions of change that I describe here.

126  Causality and Causal Explanation in Aristotle discussion of ripening and rawness (IV 3, 380a12f.), he states: “It has been said what ripening and rawness are, and why each of them is” (380b11–​12). Likewise, boiling in general is defined as the concoction by moist heat (efficient cause) of “the indeterminate contained (tou enuparchontos aoristou) in the moisture” (material cause; 380b13–​14); “so it has been stated about boiling and parboiling both what they are and why they are” (381a22–​23).43 The same pattern is followed in IV 8–​9, which focuses on the changes undergone by bodies made up of mixtures of the four basic elements and their associated qualities, rather than generation—​changes that are individuated by the subjects’ abilities to act and suffer in certain ways and not others (384b34–​385a10). He describes them as “the things spoken of in accordance with capacity and incapacity” (IV 8, 385a10–​12), which are listed as pairs of abilities and inabilities to undergo certain sorts of change by the action of an agent. According to their positive qualifications, physical compounds may be:

• • • • • • • • • • • • • • • • • •

solidifiable (pêkton) meltable (têkton) softenable by heat (malakton) softenable by water (tegkton) bendable (kampton) breakable (katakton) fragmentable (thrauston) impressible (thlaston) moldable (plaston) squeezable (pieston) ductile (helkton) malleable (elaton) splittable (schiston) cuttable (tmêton) viscous (glischron) (contrary: friable [psathuron]) compressible (pilêton) combustible (kauston) capable of giving off fumes (thumiaton)

43 It is clear that Aristotle takes there to be one statement accomplishing both—​there is no separate statement of the “What” independent of the “Why.”

Causes, Kinds, and Transformations  127 It is important that all of these are presented as distinct passive capacities related to distinct abilities of corresponding agents. Once again Aristotle goes through them all, giving determinate efficient and material causes, both of which jointly constitute the nature of the capacity and the resulting change. A nice example is making an impression (thlasis): “making an impression is the downward shifting of part of the surface by pressure or a blow, and in general by contact” (IV 9, 386a18–​20). The general causal definition seems to be the sinking of part of the surface in response to contact; impressibility is then further differentiated into subspecies: some types of impressible are easily shaped (plastic) and some are not, and they differ depending on whether the efficient cause is pressure (ôsis) or striking (plêgê), for example (386a25–​33). Malleability, by contrast, is a capacity for part of a thing’s surface to be moved both downward and sideways from a single blow (386b19–​22). All throughout, the focus of these chapters is on individuating capacities for bringing about and suffering change by a joint grasp of the determinate features of the agent and patient, just as we would expect if Aristotle’s statement about the “more intelligible” way to define changes at the end of Phys. III 3 is giving a definitional schema. The features are often quite specific, such as the different material bases for various kinds of breaking, which depend on the length, quantity, and arrangement of internal “pores” of the subject (386a9–​17, 386b27–​387a3). The discussion in book IV as a whole is also noteworthy insofar as Aristotle describes the determination of bodies as involving a three-​causal schema: “There are, then, two causes besides the matter: the agent and the quality (the agent being the cause as the origin of change, and the quality as form)” (IV 5, 382a27–​29).44 Thus, even though concoction is described as being in general a kind of completion or perfection (teleiôsis), there is no suggestion that a further final cause is required for understanding these interactions as such: we specify only the agent, the matter, and the quality.45 44 Reading ‘para’ at l. 28 with Fobes, rather than ‘peri’ with Bekker and Louis. 45 The language of “that for the sake of which” is notably absent from these chapters and indeed from the whole work except for IV 12, whose teleological orientation is both well-​known and marks a clear deviation from the rest of the work, likely in order to connect these processes to their roles in biological phenomena (cf. Lennox 2021, who also notes the lack of teleological language in these chapters). This is significant, insofar as commentators debating the scope of Aristotelian teleology have come to different conclusions about whether even basic transformations are meant to appeal irreducibly to teleology in a strong, e.g., cosmological, sense. See Sedley 1991 and Scharle 2008 on the expansive side, and Wilson 2013, ch. 5, and Henry 2019, ch. 9, on the more restricted side. In any case, a philosophically important distinction is between processes that have ends or goals besides the states in which they terminate and those that do not, since the most important and controversial cases are the former. The examples discussed here seem to be at least of the latter type.

128  Causality and Causal Explanation in Aristotle Nevertheless, this type of process is a clear instance of the form conceived of as something that comes to inhere in matter (i.e., a determinate substantial nature or property) functioning as the end (telos) of the process: The end for some things is the nature, the nature that we call form and substance; but for other things the end of concoction is towards some underlying shape (eis hupokeimenên tina morphên), whenever the moisture comes to be of such a sort and so much, either broiled or boiled or putrefied or heated in some other way; for then it is useful and we say it has been concocted. (IV 2, 379b25–​30)

The reference to usefulness may make it seem that we have deviated from natural science strictly speaking, since these are processes associated with human activities, but Aristotle is, again, explicit that with respect to causality there is no difference between these processes and the versions performed by humans.46 I suggest, then, that these passages present real definitions of causal transformations, following the schema suggested at the end of Phys. III 3, which are no less real or scientific for being definitions of transformations rather than beings or activities. Further, they are presented as complete by specifying the proper agents, the proper subjects (matter), and the forms to which the processes tend as their ends (telê), and have no need of any further teleological specification that refers to the good of anything.47 Between the two general discussions of change in Phys. III and V, and these accounts in Mete. IV of various kinds of basic interaction, we can thus give a reasonable picture of the difference between pre-​theoretical and theoretical definitions for natural transformations. A pre-​theoretical definition would present the endpoints of a change in basic categorial terms: a body’s 46 “This, then, is the kind of concoction spoken of as boiling; and it is no different with artificial tools than in natural things, when it occurs; for they will all be by the same cause” (IV 3, 381a10–​11). 47 Another noteworthy passage in this respect is Phys. VII 2, in which Aristotle individuates different types of transeunt locomotion specifically in terms of their efficient causal profile: “There are four kinds of locomotion by virtue of something else: pulling, pushing, carrying, and whirling. For all changes with respect to place lead back to these: driving is a kind of pushing whenever what moves something away from itself pushes by following on, while repelling occurs when it moves but does not follow on; throwing is when it creates a more forceful motion away from itself than the natural locomotion [of what gets moved], and the latter is carried along as long as the change prevails” (243a16–​b2). He is clear that these are definitions of some sort (horismôn, 244a7). Further, in his general discussion of the types of change in Phys. V 2, 226a32–​b1, he says that locomotion strictly speaking applies to non-​self-​movers. Thus, the basic varieties of locomotion are, it seems, to be defined ultimately with reference to the way in which they are brought about.

Causes, Kinds, and Transformations  129 going from soft to hard, from short to long, or from having a flat surface to having a surface with a depression. Theoretical definitions will often provide further individuating conditions for changes that have the same basic categorial endpoints but involve different capacities of the agent and patient. Thus, changes from hard to soft that occur by means of moisture will have different causal definitions than those that occur by means of heat. The main difference, however, will be that a pre-​theoretical definition of change in terms of the properties of the subject alone, such as “from flat-​surfaced to having a surface with a depression” are replaced by definitions that include these but add the relevant features of an agent and the material subject, such as “the sinking of a part of the surface of a soft, plastic body in response to pressure.” Where the differences are pertinent, the relevant material features can be quite specific, such as the arrangements of gaps that differentiate breakability and fragmentability noted earlier.

6.5.  Summary Besides being a pluralist about the modes of causality, Aristotle is a pluralist within each mode—​what I have called a vertical pluralist. That is, he maintains that efficient causes are not metaphysically uniform qua efficient causes, and likewise for the other modes. This, along with his denial of a special ontology for causality, means that he will not answer metaphysical questions about causality in the way many contemporary theories do. However, if we ask the broader question of how causes relate to their effects, we can see that the difficulties we face in giving a good answer are ones that he faces as well, and to which he is sensitive. I focus here particularly on a tension I have drawn out between different properties that explanatory power seems to demand of causal relationships: discreteness, contingency, and non-​accidentality. Though he does not specify a category for causes and effects, his theory of categories allows him to frame a relatively compact range of phenomena that are subject to intrinsic causal explanation, which I have labeled Transformations, Beings, and Activities. Especially important for the grounding of natural science is the first heading, Transformations, since natural science studies being insofar as it is subject to change. Transformation is in turn comprised of generation and destruction, increase and decrease

130  Causality and Causal Explanation in Aristotle (change in the category of quantity), alteration (change in the category of quality), and locomotion (change in the category of place). Aristotle’s essentialism, and its commitment to the idea that a theoretical statement of what something is names its intrinsic causes, thus extends more widely than the most commonly discussed case of substances like living beings. That is, we can distinguish between pre-​theoretical and theoretical accounts of what a thing is for a wide range of explananda, and the theoretical accounts (or real definitions) are to be framed in terms of causes. An important case in point is change: I have argued that Aristotle’s two discussions of “what change is” in Phys. III and V correspond to two distinct ways of defining changes, both in general and for specific types. The discussion in Phys. V does not use the concepts available to the natural scientist, but rather only those available to the “logical” works: for example, it defines determinate forms (lowest-​level species) of change only in terms of the categorial features applied to subjects of predication in the categories of quantity, quality, and place (with a special status for generation and destruction). The discussion in Phys. III, by contrast, does make use of the natural-​scientific concepts of form and matter, and especially actuality and potentiality. It also, I have argued, contains a claim about natural-​scientific (i.e., theoretical rather than pre-​theoretical) definitions of different species of change: such definitions should specify the basis not just of the patient’s potentiality but also the agent’s ability to bring about the change in the patient—​scientifically speaking, they form a unit. I have argued that he follows precisely this pattern in discussing various kinds of transformation and change in the Meteorology, stating both “what and why” certain species of change are, in terms that correspond to this demand. Thus, the theoretical definitions for at least certain species of natural change will specify their intrinsic causes, including not just the form that constitutes the endpoint of the change but also the precise features of the agent (the efficient cause) and patient (the material cause) by virtue of which they are capable of interacting in such a way as to produce the change. As I shall argue in the next chapter, however, the pattern for these theoretical definitions is not uniform either—​there is no single schema that applies to all natural-​scientific definitions. There are key differences to which the natural scientist must attend, depending again on the type of phenomenon in question.

7 Causal Kinds and Causal Profiles 7.1.  Real Definitions and Causal Profiles From the perspective of this discussion of the two accounts of change and their corresponding ways of defining changes, the Met. VII 17 passage about essence and cause (1041a24–​32, given earlier) looks like an incomplete statement about real definitions. We do indeed seek the cause by which some F “belongs” to some subject S, and it may be either an efficient or a final cause—​ or perhaps we must cite both. However, the scientific definition does not cite only this cause, nor are the formal and material causes simply cited as they appear to the non-​scientist. The efficient and/​or final cause may be said to have a kind of primacy in the definition, since it seems that in general we add these when we move from a pre-​theoretical (categorial) grasp of a change, in terms of a subject and contraries, to a theoretical one.1 At the same time, a causal definition does not simply take the predicate from a pre-​theoretical definition and interpolate the cause responsible for the predicate’s holding of the subject, yielding a statement of the sort “T is a bringing about of F in S by the action of A.” The causal definition contains a precise statement of the material cause as well, that is, the feature or features by which the subject S of the pre-​ theoretical definition is capable of coming to bear F.2 The “F” itself may be further refined as well in the theoretical definition, since some kinds of interaction appear to differ depending on the precise result, for example, as malleable things are distinguished from the more general category of impressible things by virtue of the fact that part of their surface moves not just down, but down and to the side (386b19–​22).3 1 This point is perhaps at work in passages where Aristotle seems to claim that only two causes are at issue in natural science, namely the efficient cause and the final cause (where this may be the form in its role as the endpoint of a transformation): most prominently, Phys. II 7, 198a33–​b3; and PA I 1, 639b11f. 2 As he puts it most crisply in his discussion of action and passion: “matter insofar as it is matter is capable of being affected” (“hê d’hulê hêi hulê pathêtikon,” GC I 7, 324b18). 3 Some notion of a subject for the predicate is either implicit or explicit in a pre-​theoretical account of a natural transformation, but the precise nature and content of such accounts are hardly clear,

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0008

132  Causality and Causal Explanation in Aristotle Arguably, in such a definition, the efficient and/​or final cause has a kind of priority, as being the primary cause by which some (precise) F inheres in some (precise) S, so that the VII 17 passage is still correct on the whole about what we search for in attempting to grasp the essence of a phenomenon in general. Where something is F as a primitive fact, there is no further cause of its inhering in S, and so the scientific definition is of the relevant F itself.4 But where there is an intrinsic efficient and/​or a final cause by virtue of which F holds of S, then these occupy a special role in the theoretical definition. Taking these points about different types of real definition for different sorts of phenomena together, I think we can conclude that Aristotle distinguishes at least between two types of what I will call causal profile, which I will label “origin-​dominant” and “end-​dominant.”5 A causal profile is a distinctive structure that characterizes a sub-​class of causal definitions. Thus, for example, a basic change, such as the kind of “chemical” change discussed earlier, has a three-​component profile, since it is completed by naming the subject, the property-​as-​endpoint, and the agent. Since the efficient cause has primacy over the material cause in this kind of change, in ways that will be more fully elaborated later (see especially § 7.3), it is “origin-​dominant.” A teleological process like cautery, on the other hand, will have a four-​component profile—​ searing a certain kind of surface by the action of a certain type of heat for the sake of healing. Since the final cause has primacy in this profile, again in ways that will be further specified later, it is “end-​dominant.” The distinction between origin-​dominant and end-​dominant profiles reflects the idea, suggested in Met. VII 17, that for some types of natural phenomena, a scientific account will take the efficient-​causal power at work as primary, and understand the formal and material causes relative to it, as what the agent accomplishes by acting on a certain sort of subject. Other phenomena will be defined with the final cause taken as primary, such that the other types of cause are understood in relation to it in the full scientific account.6 as we can see from discussions about “phainomena” and nominal definition in Aristotle; see, e.g., Bolton 1976; Deslauriers 2007, ch. 2; Charles 2010; Modrak 2010; and Sedley 2015. 4 Cf. Apo. II 9, and Deslauriers 2007, ch. 2. 5 Here it should be clear that ‘origin-​dominant’ refers to profiles in which the efficient cause has primacy. The phrase is not ideal, since ‘origin’ is sometimes used to translate ‘archê’ (which I mostly translate by ‘principle’) and Aristotle thinks that every cause is an archê, including ends. However, other options are even less ideal, so I will rely on context and explicit warnings where necessary to avoid confusion. 6 Cf. Met. III 2, 996b22–​23. It is worth comparing my suggestion to Charles 2000, 215, et passim. Charles also notes the passage at VII 17, 1041a28–​30, but his conclusion is that essences are

Causal Kinds and Causal Profiles  133 Because of the variety of different beings, transformations, and activities that are subject to causal explanation, there are still further differentiations that can be made, but because natural science deals with changeable being, this distinction between origin-​dominant and end-​dominant profiles is of primary importance, as I shall argue later.

7.2.  The Varieties of Causal Profile Aristotle thus combines his four-​causal framework with his essentialism to yield the view that genuine regularities, that is, those things that have intrinsic causes and thus occur “always or for the most part” in the same way, have causal definitions, but will have different causal profiles depending on what sort of transformation, being, or activity they are. This result, in turn, has implications for how he can respond to our primary questions: What sorts of thing are susceptible to causal explanation? How do they relate to their causes? The general response to the first question is that genuine regularities have both pre-​theoretical and real (causal) definitions that specify their intrinsic causes, and that individual transformations, beings, and activities are susceptible to causal explanation to the extent that and insofar as they exemplify genuine regularities with intrinsic causes. The nature and structure of the causal explanation for any instance of a given kind will vary depending on the causal profile of the regularity that it exemplifies. Likewise, in response to the second question, we can only ascertain the relationship between an effect and its causes by understanding the relationship of the effect to the precise, intrinsic causes picked out in its scientific

constituted by single causes that explain a thing’s per se features; for some kinds this will be a single efficient cause, for others a final cause. On his view, where something’s essence is its teleological cause, this, and only this, “is sufficient by itself to make the phenomenon of anger fully intelligible to us” (215). This conclusion is developed in the course of reflecting on the interdependence between Aristotle’s theory of definition (and hence essence) and his theory of demonstration. My suggestion here is rather that the essence of a natural kind with intrinsic causes will be constituted by all of its intrinsic causes, and that for beings that have intrinsic efficient and/​or final causes there will in general be one or the other that is dominant, in the sense that the other causes of the phenomenon are determined in relation to it. This is most clearly seen in the case of matter: the precise proper subject of a change with an origin-​dominant profile is determined relative to the agent, and the endpoint of the change is simply whatever property naturally results from their interaction. The precise proper subject of a change with an end-​dominant profile, by contrast, is determined relative to the final cause. I discuss this aspect of natural kinds and their causal essences, and its implications, later in this chapter.

134  Causality and Causal Explanation in Aristotle definition, since these relationships will be different for different types of phenomena. Starting with the primary division among causal explananda between what I have called transformations, beings, and activities, the following further distinctions are salient, insofar as they represent regularities with causal definitions but with different causal profiles. They are not meant to be exhaustive, but are rather restricted to cases that Aristotle seems to describe in terms of intrinsic causal definitions. (I am setting aside mental phenomena such as perception and rational action, as these introduce further complexity and controversy. I am also ignoring, for the moment, differences between artificial and natural kinds, since they introduce the complexity noted earlier: artifacts have intrinsic causes without qualification, but are not substances without qualification, and so understanding the relationship between their causal profiles and those of natural things requires understanding the precise ways in which craft is supposed to illuminate nature.7) Transformations: (i) Transeunt processes such as boiling or bending, resulting either in generation (e.g., via concoction) or a special property (e.g., hard or soft)8 These are the cases just discussed, which exemplify the schema of Phys. III 3, being defined as the actualities of “what is capable of acting and being acted upon, as such” (202b26–​27). Their definitions will cite efficient and material causes which are related to one another in that the natural scientist must grasp precisely those features of both the agent and the subject by which the former is capable of acting on the latter, and the latter is capable of being acted upon by the former. Since these transformations involve interactions grounded in capacities of the agent and patient themselves, it looks as though their definitions will cite, again using Gill’s 2005 terminology, special properties of their subjects: we must cite just that feature of the agent and patient by which each is capable of bringing about change and being changed with respect to just these properties.9 7 See § 11.2. 8 Aristotle says in Mete. IV 4 that these are special properties of material compounds, defined in terms of the surfaces of bodies (382a8–​14). 9 As a limiting case, this category also probably includes the inter-​transformation of the elements, i.e., the processes by which water is turned into air, and so on. Aristotle’s account of that transformation is subject to a variety of complexities, both textual and philosophical, not least because it raises the question of prime matter. On inter-​elemental transformation, see especially DC III 6 and GC II 4–​7, as well as Gill 1989, ch. 2; and Lewis 2008.

Causal Kinds and Causal Profiles  135 (ii) Regular, definable change resulting in a co-​incidental property The eclipse example, as discussed in Met. VIII 4, seems like an instance of this category.10 Eclipses are defined in terms of the interposition of the Earth (efficient cause) bringing about a deprivation of light (formal cause) in the Moon (subject), to which the formal cause does not belong intrinsically in either of the senses Aristotle recognizes: “being deprived of light” is neither an essential nor a special property of the Moon.11 That is, the property of being deprived of light does not figure in the essence of the Moon, nor does the Moon figure in the essence of that property the way number is in the essence of odd. So in this case, only the formal and efficient causes are intrinsic causes of the Moon’s being deprived of light, even though the definition of a lunar eclipse refers to all three causes. (iii) Changes essential to the continued existence of living substances A nice example of a recurring change within an organism is provided by sleep. At the end of De Somno, Aristotle says that he has stated the cause of sleep, namely the compression around the primary perceptual faculty by an upward movement of bodily material due to congenital heat (3, 458a25–​28), as well as what sleep is, namely the seizing up of the primary perceptual faculty so as to make it incapable of activity (formal cause), for the sake of the animal’s preservation (final cause) (3, 458a28–​32). Sleep is thus necessary for the organism, and in this case its purpose is included in its definition, though it is unclear from the passage whether Aristotle wishes to include the efficient cause in the account of what sleep is.12 (iv) Generation of the components (e.g., animal parts) that are essential to the species or kind

10 1044b3–​15; the eclipse example is also prominent in the discussion of definition and demonstration in APo. II, especially chs. 1–​2 and 8. The discussion in Met. VIII is briefer, but more useful for present purposes insofar as Aristotle describes it in relation to the available options provided by the four-​causal schema. For a full treatment of the discussion in the APo., see Goldin 1999. 11 For the distinction see earlier, p. 58. 12 I take it that the efficient cause is the compression of the perceptual faculty (i.e., the heart) by the upward-​moving material; the whole process is intertwined with Aristotle’s account of digestion and its relation to blood. Much about this passage is controversial, though, including the precise efficient cause and what plays the role of the material cause for sleep, and in what way. Sleep is usefully compared and contrasted with the eclipse example; see especially Code 2015, and compare Met. VIII 4, 1044b15–​20.

136  Causality and Causal Explanation in Aristotle The generation of any living thing is a multistage process following a regular sequence, which Aristotle attempts to describe and analyze in the Generation of Animals. The main stages are those resulting in parts, and they seem to be, roughly, processes in which the kinds of “chemical” changes described in the Meteorology (Mete.) are marshalled and organized for the sake of generating flesh, bone, hearts, lungs, and so on, starting with and proceeding from the action of male sperma on the female katamênia.13 When a given part is included in the definition of the animal—​that is, a part of the body corresponding to its essential life activities, the way sense organs are essential to animal life—​the process of its generation is analyzed as a specific kind of action on a specific sort of material by an agent, for the sake of producing an organ of that conformation and properties, by virtue of which it contributes to the animal’s life activities. The specific features of the material are relative to the organ being developed, and the structure and properties of the organ are in turn teleologically explained (see headings vii and ix) by the activity to which it contributes. So here we have (1) an agent (at the origin, the male parent; proximately the animal’s heat in the sperma, GA II 3, 736b29–​35), (2) a patient which is precisely defined by its ability to be acted upon in such a way as to yield (3) an organ with precisely those properties that are in the essence of the organ itself, that is, for the sake of an intermediate end. The end of that process, namely the organ, will be subject to (4) its own teleological explanation or be part of a series which eventually terminates in some activity which is an ultimate end, perhaps the unified activity that constitutes the organism’s way of life, or some more restricted activity.14 In contrast to the efficient causes of basic transeunt interactions, in these cases the efficient cause is subordinate to a final cause: the parts or properties of the origin of the process are themselves teleologically defined (e.g., reproductive organs, sperma, or the generative capacity of soul). This is what Aristotle means by arguing in Phys. II that nature is an internal efficient cause that acts for the sake of something. He expresses the idea with more precision in the GA: 13 See especially GA II 1, and the NRC principle applied to them at II 6, 743a21–​6; for a recent study of animal generation specifically, see Henry 2019. 14 There are a variety of difficulties and controversies about identifying a unified essence as the ultimate explanatory principle for living beings, especially taking into account all the complexities of Aristotle’s biological works and his views about definition. Such a principle would need to be unified “vertically” (i.e., the definition of a species should not turn out to be a mere conjunction) as well as “horizontally” (i.e., the various features Aristotle thinks are basic to a given kind, such as its modes of movement, reproduction, nutrition, and so on should not be a mere aggregate). On the former problem the literature is especially vast; for a starting point, see Gill 2005; Deslauriers 2007; and Code 2010. On the latter, see especially Gotthelf 1999, 47–​48; Charles 2000, ch. 12; and Lennox 2010.

Causal Kinds and Causal Profiles  137 “That for the sake of which” and what is for its sake are different; one of them is prior in generation, the other in substance. But there are also two differences for what is for the sake of that [i.e., what promotes the end]; for the one is the origin of the change, while the other is what “that for the sake of which” makes use of. I mean, for example, both what is capable of generating and what acts as an instrument for what is generated; for one of these must be present earlier, namely what is capable of acting, as the one who teaches is prior to the learner, whereas pipes are posterior to the one learning to play the pipes; for it is superfluous for there to be pipes for those who do not know how to play the pipes. So since there are three things—​ one being the end, which we call that for the sake of which, second being the things for the sake of this, the principle that is capable of bringing about change and of generating (for what is capable of acting and generating, as such, is relative to what is accomplished and generated), and third being what is useful and what the end makes us of—​first there must then be present some part in that which is the principle of change (for this is immediately a part of the end, one and primary), next after this the whole and the end, and third and finally their parts that are like instruments in relation to certain uses. Thus, if there is something of this sort, which necessarily is present in animals, what has the principle and end of the whole nature, this necessarily comes to be first, first insofar as it is capable of causing change, but insofar as it is a part of the end, it comes along with the whole. (II 6, 742a20–​b3; following Peck’s text, my emphasis)

Here we see especially clearly in the italicized passages that not only does the final cause take priority, but in fact the efficient cause itself is determined, properly speaking, only relative to it (742a30–​31). An important related example in this category is in fact the formation of the initial matter for generation (from the female) and sperma from the male, both of which he calls “residues,” and which constitute the initial material and efficient causes in a process of generation (GA I 18–​19, 724a14ff.). This is the process which Aristotle thinks is analogous to manufacturing bricks, cutting timber, and making tools for the sake of building a house. As noted earlier, I think Aristotle is committed to the view that these cases are causally on a par and not merely analogous, even if houses are merely analogues of substances. Other prime examples he mentions as having the same profile include the heart (which is especially important in that it is the first organ

138  Causality and Causal Explanation in Aristotle formed which is proper to the generated organism GA II 4, 739b34ff.), as well as the “uniform” parts such as flesh, sinew, skin, bone, and so on (743a3ff.).15 (v) Generation and change resulting in non-​essential but regularly recurring features in teleological contexts Examples in this category include eye color and various qualities of hair such as length and texture, which are not intrinsically related to what brings them about, but rather are necessary consequences of processes which are for the sake of something else.16 So their causal profile includes (1) a specific sort of efficient cause acting on (2) a specific sort of matter, where the matter and efficient cause are again intrinsically related, and the resulting state is a “special property” of its subject (e.g., color in a surface). That state, however, is not an intermediate end, nor does it bear any intrinsic connection to the nature of the organism as a whole, nor, finally, is the efficient cause subordinate to this feature as its final cause. (vi) Generation of a substance Aristotle states clearly enough that the intrinsic cause of the generation of a living thing is (except for spontaneously generated organisms) (1) another animal of the same species, acting (1a) by way of an intermediate efficient cause or causes on (2) material which is itself a product of physiological processes directed at the creation of something with the potential to be acted upon by that intermediate efficient cause, for the sake of generating (3) another being of its kind. This is a case—​the first among the ones I have described thus far—​ exemplifying Aristotle’s well-​ known claim that the formal, final, and efficient causal explanations often refer back to one thing (canonically stated at Phys. II 7, 198a24–​27). I will discuss this “identity” claim more later, but it is worth noting just how much of a special case it is relative to the array of causally defined kinds.

15 For the uniform parts Aristotle specifically refers to the Mete. discussion of how and in what cases heat or cold causes things to solidify (743a6–​8). 16 At least, in his discussion of eye color Aristotle does not appear to treat it as a co-​incidental result of another process. Rather, the generation of an eye must involve its becoming one color or another, and the precise features of the matter and the agent will account for which color it comes to be. See especially Gen. An. V 1, 778a32–​b19; V 3, 782b11f.; and Gotthelf and Leunissen 2010.

Causal Kinds and Causal Profiles  139 Beings: Even though what I have labeled “beings,” which in this context is shorthand for both substances and their states, are the results of the transformations described earlier, they have their own causal definitions, which differ in various ways from those of the transformations from which they result. And, Aristotle is clear, the beings are more fundamental for an account of nature. An obvious difference is that for beings, the states or forms which characterize them are inherent in their subjects, whereas they are extrinsic (in the standard sense of the term) to the transformations—​when the end-​states have been achieved, the transformations no longer exist.17 So whereas these states and natures function as the ends of those transformations (whether or not they were for the sake of anything further), in completed beings and states they function simply as formal causes that inhere in their proper subjects. The reason for marking the distinction between profiles for transformations and beings, however, is not just that inherence is a metaphysically different relationship from being an external endpoint marking the limit of a process. Rather, there will also be different static causal relationships within a complex entity that are not captured in accounts of the transformations that brought them about. For example, the various relationships between an organism’s form and its characteristic life activities such as seeking food and reproduction, on the one hand, and the matter and organization of its parts, on the other, are not features of the animal’s generation (and of course the matter for generation is different from the body of the mature organism anyway). The reverse is the case: the structure of the generative process itself is determined by these relationships among elements of the complete, functioning organism. As Aristotle puts it, coming-​to-​be is for the sake of being and not vice versa, so the full causal profile of the complete being is necessary for and scientifically prior to the causal profile of the transformation that results in it.18 Finally, Aristotle recognizes the possibility that at least in some contexts something can come to be for the sake of one thing but exist or persist for the sake of something else.19 Thus, the end that at least proximately explains 17 See Phys. III 1, 201b5–​15. 18 See especially Met. IX 8, 1049b12–​17 and 1050a4–​b3, for the general point; as applied to living things specifically, see PA I 1, 640a13–​19. 19 A prime example of this phenomenon is the polis (Pol. I 2, 1252b29–​30)—​which comes into being for the sake of living, but exists for the sake of living well—​but there is no reason to exclude it from nature; indeed, the heart seems to exhibit a similar shift, given its initial role in promoting the development of the embryo, which enables it later to fulfill its various functions in the mature animal (including, he thinks, functions related to nutrition as well as perception and action).

140  Causality and Causal Explanation in Aristotle a transformation may be different from the end that explains the resultant entity or state. The main types of causal profile for beings are thus as follows:

(vii) Essential state/​feature

Bone is hard, and so derives from material that is capable of being hardened, but its hardness is causally related in one direction to its function (protecting organs, supporting flesh, and so on—​see PA II 9), and in another direction to other features of the organism as a whole (the resulting shape of the organism, limitations or consequences for the way the creature moves, and so on). So the state of an entity that consists in its having an essential property, like hardness for bone, has intrinsic causes of all four types: in this case a quality (form) in its proper subject (material capable of being hard), an agent in the “chemical” process resulting in the hardening of the nutritive material that becomes bone, and an intrinsic end or ends that it promotes.20 (viii) Co-​incidental state/​feature of a substance Co-​incidental features in this sense inhere in a substance as subject, unlike, say, merely co-​incidental features like being in shadow, which are not really features of the substance even in the contingent way Socrates’s pallor is a contingent property of the surface of his body. Those features that are the intrinsic results of change are always, it seems, a “special” property of some aspect of that substance, for example, size of the body insofar as it takes up space, or color of the body’s surface.21 As we have seen, such states may or may not have further teleological causes. (ix) Intrinsic parts of wholes Organs themselves are essentially teleological and have their matter and form intrinsically—​the heart is shaped this way out of tissues with these properties for the sake of performing its function, on Aristotle’s understanding of it. Because having any individual organ is partially constitutive of being a 20 For an account of such nutritive processes, see GA II 6, 743a1ff. This constitutes another difference in general between the efficient causes of the generation of such parts, due to the parent, and their maintenance, due to the organism itself. 21 This point is made explicit in the discussion of the senses of ‘in’: see Phys. IV 3, 210a27–​b10.

Causal Kinds and Causal Profiles  141 complete organism, its primary efficient cause reflects this: while organs, of course, result from local efficient causal processes, and so we can, say, determine just what features of a developing embryo or fetus are the proximate agents of their formation at just these stages of the whole process of generation, their primary efficient cause is simply the origin of the substance as a whole, that is, the parent.22 (x) Natural substances As we have seen, Aristotle seems to state clearly enough that natural things are like the snub: they are a “this-​in-​this,” that is, form in proper matter. The exact causal profile of substance and how it is to be defined is controversial, in the ways mentioned earlier and others besides, and so I will not take a stand on it here—​especially since my claim is that we can get a better understanding of the issues involved by looking at the other cases. Besides, one way of thinking about Aristotle’s difficult discussions of natural substance is precisely that he is attempting to work out its causal profile, which turns out to be far less obvious than that of baking bricks.23 Activities: Finally, we come to activities in what we might call the strict sense, that is, those actualities or aspects of them which Aristotle carefully attempts to distinguish from changes (kinêseis) in Met. IX. Here, too, there is a great deal of controversy, and the clearest cases for Aristotle take us to the limits of what he counts as natural science as such—​perhaps past them, since many of them are psychological in Aristotle’s sense, and the precise status of his psychology in relation to natural science is disputed. Nevertheless, some broad differences in causal profile are clear enough and useful to note. One of the primary differences is that for paradigm activities, their ends are continuously “present” throughout their existence, whereas for changes the ends are extrinsic in the sense noted earlier.24 Paradigm activities are also examples of what Aristotle calls “self-​qua-​self ” (efficient) causation, as opposed to “transeunt” or self-​qua-​other causation. So, minimally, their causal profiles must reflect the fact that they are actualities in which something acts 22 For a crisp statement, see GA II 4, 740b18–​741a2. 23 For the same reason, I will not here take a position on the controversial case of the affections (pathê) of the soul as discussed in DA I 1. 24 The precise nature of the distinction between activities (energeiai) and changes, as well as the texts in which the distinction is drawn, is hotly disputed. See Ackrill 1965; Gill 1989, ch. 7; Menn 1994; and, for a controversial reading, Burnyeat 2008.

142  Causality and Causal Explanation in Aristotle on itself “qua itself,” and whose final causes are themselves somehow fully internal.25 Further, many such activities are ultimate, in the sense that they reflect the nature of the substance itself—​they are the activities definitive of the kind and for the sake of which its body is constituted as it is. Not all activities are like this—​perhaps for humans, digestion and walking would count as activities which are not ultimate or directly related to their essences. The line is not a stark one, however, and perhaps cannot be—​some of the controversy over the distinction between change and activity may even reflect this. The causal profiles distinguished here reflect broad and important distinctions Aristotle draws between the kinds of explanandum with which a natural scientist is concerned, such that fully understanding them involves recognizing causal elements arrayed and inter-​related in importantly different ways. Some of the profiles will be open to objections as I have drawn them, while other cases, as noted, are in need of further development, and Aristotle’s account of them may be unclear precisely because they are philosophically difficult. Nor are they all meant to represent sharp divisions: in many cases Aristotle’s conclusions are tentative or unclear, and for many types, as already mentioned, the connections between them are tight enough to be almost seamless, as between the generation and existence of a living being. What is most important to note is that there is this rich variety of causal profiles that correspond to different types of phenomena, all of which, Aristotle thinks, are subject to causal explanation in their own right. Thus, when the Aristotelian natural scientist thinks that something is susceptible to causal explanation, one of the first tasks is to determine what sort of causal profile is most likely to fit, in order to know what kinds of intrinsic cause it has, and how they relate to each other as well as the explanandum itself.26 Not all phenomena are as well-​integrated as those involved in producing and maintaining living things, and an inquirer must decide when to stop looking for that kind of integration in any given case. Many of these causal profiles are clearly only relevant, further, to disciplines in

25 See especially Met. IX 8, 1049b4f. 26 Thus, for example, difficulties commentators have had in finding four causes for certain phenomena such as human action may be due to the fact that they are kinds with three-​component causal profiles—​there may be, in the specification of their real definitions, no distinct formal cause of at least some actions, for example (i.e., nothing analogous to the shape a developing organ comes to have), but rather only efficient (desire and/​or decision), final (the activity performed if it is an ultimate end), and material (the aspect[s]‌of the body by which the person is capable of the activity) causes.

Causal Kinds and Causal Profiles  143 which at least some efficient causes are teleologically determined. Faced with a regular phenomenon, a biologist must figure out, among other things, whether it has or might have an origin-​dominant or end-​dominant profile, and of what sort. This is not an issue for someone investigating air or ocean currents, by contrast. For some disciplines, the relevance of these profiles is less clear, at least for Aristotle. Many celestial phenomena (like eclipses) have origin-​dominant profiles, but since that domain is so remote and Aristotle thinks that at least some of its entities are alive and intelligent, it is an open question which phenomena might have end-​dominant profiles, and whether the order of motions of the universe as a whole might turn out to have one. There is also an important intermediate case I have not described, namely the self-​maintaining activity of the living organism. All of the bodily parts that are formed in the process of generation are in turn maintained by the nutritive capacities and activities of the complete organism. Much of the “chemistry” will be the same as in generation, by which food is turned into blood, and blood into bodily parts, but the aim and the origin (i.e., the efficient cause) are different: nutrition is for the sake of preservation or continued existence, not coming-​to-​be, and it is brought about by the soul of the organism itself, not the parent.27 Its global causal profile seems, in fact, to cut across the three categories of transformation, being, and activity, since it is, as a whole, an activity of the soul of a single substance, which uses transformational processes as intermediates or tools to transform its food, for the sake of preserving itself as it is. There are more complicated cases as well, especially in the biological domain, where Aristotle seems to indicate that certain features or parts of animals do not follow the straightforward patterns in vii–​ix. There are numerous cases for example, such as the omentum and the mesentery, where Aristotle contrasts the process by which a property or organ comes to be as resulting from (mere) necessity, while nonetheless attributing a function to what results. One way of glossing these cases is that the transformation resulting in the mesentery, being a result of necessity, does not have an intrinsic efficient cause (the organ is a co-​incidental result of a transformation with a different intrinsic end), but the organ itself, as a certain kind of being, has a causal profile with an intrinsic final cause.28 However we read these 27 On the soul as the efficient cause of nutrition, see Johansen 2012, ch. 7. 28 The precise accounts of these cases are controversial, and they differ in important details, but most commentators accept that Aristotle describes some features of living things this way. The omentum is described in PA IV 3, on which see Lennox’s 2001 commentary (ad loc.), and Henry 2019, 186–​87; for the mesentery, see PA IV 4. For some of the controversy, see Leunissen 2010, 3.2;

144  Causality and Causal Explanation in Aristotle cases, it is important to register that subtle shifts in the explanandum at issue or in the role a component may play in different causal profiles—​the way a form can be the endpoint in relation to a change and the essence in relation to a state—​can yield an overall explanatory picture of great complexity. We can see from the earlier discussion that the distinction between what I have called origin-​dominant and end-​dominant causal profiles marks a key difference among the different types of explananda. Another important distinction should be noted between immediate and mediated causes, that is, between those in which a primary efficient cause directly brings about its effect, the way something hot and dry warms up and dries out something moist and cold, and those in which the ultimate origin acts by way of intermediate efficient causes, the way a parent reproduces by means of special organs and seed, which in turn initiate a complex process that unfolds in the embryo. The same distinction also applies to ends, some of which are immediate and some of which are intermediate. The two pairs of distinctions interact in important ways. Typically, the efficient causes in end-​dominant profiles will be mediated by further actions and tools, and so they indicate the importance for Aristotle of naming not just proximate but especially ultimate efficient causes or starting points. By contrast, the paradigm cases of origin-​dominant profiles such as basic “chemical” interactions involve immediate efficient causes, which make them especially suitable, from the natural scientist’s perspective, to function as ultimate “building blocks” for complex processes.

and Henry 2019, ch. 8, appendix. Gotthelf 1987a argues that all genuine teleological relationships in a complete organism must also be such that the process that produced them is for their sake, and so would have us interpret these cases differently. It may seem difficult for Aristotle to maintain that a biological feature exists for the sake of a given function even if it did not come to be for the sake of that function, since he is not able to draw a distinction between, say, traits that arise through chance mutation but are preserved in virtue of adaptiveness. Aristotle does, however, distinguish between proximate and ultimate efficient causes, so it is open to him to say that such features have no proximate intrinsic efficient cause, but they do have an ultimate intrinsic efficient cause—​the nature of the organism. He also thinks that living things actively preserve their bodies through nutrition, and actively remove waste, so it is open to him to claim that, like the polis, a feature may persist and be preserved for the sake of a function, even if it does not come to be for the sake of that function. (He is usually careful to include rest or stability, êremêsis, in the remit of the efficient cause, as at Phys. II 3, 194b30). As an empirical matter, that is, if a given part or feature has an intrinsic function in an animal, it can still be an open question whether the process that results in that feature is intrinsically for the sake of producing it. The difference overlaps but should not be confused with the distinction between primary and secondary teleology drawn by Leunissen 2010, § 3.2; for a critique of that distinction, see Henry 2019, 187–​95.

Causal Kinds and Causal Profiles  145

7.3.  Connections and Correspondences to Other Distinctions Some of these distinctions with respect to causal profile are marked by Aristotle not just as constituting ontological differences, but as instances which involve different uses or senses of key causal terms which, he thinks, need clarification. That is, the differences among causal profiles are important enough that they do not simply constitute straightforward applications of the same term in a different context. With respect to material causes, there are, of course, the obvious differences between matter as the proper subject for co-​incidental properties, such as color, and matter as the subject of a substantial form, as well as the corresponding differences between the subject of change and the subject of generation. The difference is so significant that in one passage Aristotle says that “the matter most strictly speaking (malista kuriôs) is the subject that admits of generation and destruction, but also is in a way the [subject] for the other transformations, since all of the subjects are capable of admitting certain contraries” (GC I 4, 320a2–​5). Some commentators read this as even asserting that the matter of generation is more properly speaking a material cause than the material bases of change, but I do not think it needs to or should be read this way.29 There are also notable differences between material and efficient causes in origin-​dominant as opposed to end-​dominant profiles, in paradigm cases. The kinds of basic interaction described in the Meteorology are grounded in independently specifiable basic properties—​hot, cold, moist, dry—​and closely related dispositional properties like hardness and softness. While these properties only constitute causal capacities relative to each other and the change they can bring about, they appear to be nonetheless independent of one another, and to have a different modal profile, since Aristotle thinks that the same basic properties can constitute different capacities relative to different patients or agents. Thus, though such processes have natural, 29 In general and in the most prominent passages, especially the main discussions of matter in Phys. I and the GC, it is clear that the matter for change is an equally good instance of a material cause. Indeed, in Phys. I it is the paradigmatic notion, and Aristotle never implies there that it is only an approximation on the way to grasping material causes in the strict sense. (In fact, I think he is committed to the claim that they are both genuine and genuinely distinct, precisely in virtue of his insistence that all these forms of transformation are themselves genuine and genuinely distinct.) Cf. Phys II 2, 194b8–​9; Phys. III 1, 201a9–​15; Met. VIII 1, 1042a32–​b3; XII 2, 1069b9–​20; and Broadie 2004, 135–​36.

146  Causality and Causal Explanation in Aristotle determinate endpoints toward which they tend if nothing impedes them, their specific endpoints depend on, and vary in accordance with, the pairings of material and efficient “disposition partners.”30 Material and efficient causes in end-​dominant profiles, by contrast, are functionally determined, in that they tend to be features of things that have no independent unity apart from their roles relative to that specific end, and which do not constitute different potentialities in relation to different patients. Aristotle’s description of end-​directed matter as hypothetically necessary involves distinguishing it in ways that do not pertain directly to its “necessary nature” (the basic properties and propensities derived from its material components, which are mere necessary conditions, Phys. II 9, 200a5–​11), but rather to whatever functional feature of the composition is relative to the end; this sometimes yields a disjunctive specification, as in the example of the saw (PA I 1, 642a8–​11), since what makes it the matter for that kind of object is not so much what kind of metal it is but its combination of hardness, flexibility, and so on, which may be common to several kinds of material. This is perhaps also the point of Aristotle’s distinction between the producing craft and the directive craft in Phys. II 2, where the natural scientist concerned with things’ natures is supposed to understand them in the way the smith needs to understand bronze—​by reference to their end-​relative features, which are not the same as those understood by the metallurge (194a36–​b8). (This is indeed where he states flatly that matter is something relative [pros ti, 194b8].) Efficient causes for end-​directed profiles are, of course, similarly determined and unified relative to their end: there is no unity to the properties that make someone a doctor, for example, other than that they jointly constitute an ability to make someone healthy (or sick, Met. IX 5, 1048a8–​11). Aristotle also distinguishes between being an “archê metablêtikê”—​a transforming origin—​in something else or in oneself qua other, and being an “archê kinetikê”—​an origin for change—​not in another but in oneself “qua 30 To borrow a phrase from C. B. Martin. See Mete. IV 7, 383b18–​19: “Whatever has more water than earth is thickened by fire alone, then, while whatever has more earth is solidified”; likewise, different agents will bring about different changes with respect to the same qualified matter: “It is possible for different things to come to be from a single matter; for example, both a chest and a bed from wood. But in other cases, there is necessarily different matter for different things; for example, a saw would not come to be from wood, nor is this in the power of the cause that brings about change; for one cannot make a saw out of wool or wood. Therefore, if it is possible to make the same thing from different matter, it is clear that the craft and principle, in the sense of the origin of the change, is the same; for if both the matter and what brings about the change are different, so also is what comes to be” (Met. VIII 4, 1044a25–​32).

Causal Kinds and Causal Profiles  147 oneself ” (Met. IX 8, 1049b5–​10). This distinction in turn fits with one between efficient causes whose “actuality” (energeia) is in something else (the product or patient) and those whose actuality is in the same being, and not merely in a spatial sense: For those things for which what comes to be is something different, besides their exercise, their actuality is in what is made (for example, the building is in what gets built, and the weaving is in what gets woven, and likewise for the rest; and in general, the change is in what gets changed); but for those things for which there is not some other result besides the activity, the actuality is present in them (for example the seeing is in the one seeing, and the contemplation is in the one contemplating, and life is in the soul, which is why happiness is so as well; for it is a certain kind of life). (1050a30–​b2)

Thus, this passage also affirms a difference among end-​directed efficient causes between those whose actualities are ends-​in-​themselves, exemplified most of all by the activities characteristic of substance, and those whose actualities are not—​that is, between the efficient causes for activity profiles and transeunt change profiles. Likewise, Aristotle is at pains in Met. IX 1–​6 to draw a distinction between the senses of potentiality and actuality related to change and those corresponding to activities like seeing and thinking, using the more familiar notion of a transeunt power to bring about change as a means of approaching the target notion—​actuality (energeia)—​indirectly. His way of proceeding shows that he recognizes clearly that the distinction is not obvious and constitutes a philosophical development that his audience will not take as trivial.31 Thus, differences in causal profile tend to coincide with distinctions Aristotle draws in the corpus which do not merely amount to differences of kind, but need marking in stronger ways, often requiring a good amount of philosophical work to discern. So even though Aristotle does not describe the notion of a causal profile as I have developed it here, it is reasonable to take it as capturing some of his key claims and commitments about causality. 31 See especially the methodological remark at Met. IX 6, 1048a25–​30, and the summation of the discussion of the nature of potentiality in IX 7, especially as it relates to the difference that depends on whether the metaphysical subject is a substance or not (1049a18–​b3). In addition to the pieces cited earlier (p. 142 n. 25) in relation to the distinction between the two notions of actuality in IX, see also Frede 1994; Makin 2006; Beere 2009; Johansen 2011.

148  Causality and Causal Explanation in Aristotle One might raise a worry at this stage whether Aristotle’s four primary causal roles are therefore too metaphysically heterogeneous to be informative or constitute “natural joints.” If the relationships included under “matter” turn out to involve genuinely different types of relationship, what are the grounds for thinking that they have anything important in common? And if they do, why not think that this common feature is the relevant causal property, rather than whatever differentiates them? Similar worries are and have been raised about Aristotle’s approach to other concepts like soul, his critiques of Platonic notions like the Good—​and indeed cause in general. His position on such matters is a philosophically complicated one: he must maintain that, for example, the different types of material causation relate to genuinely different types and/​or senses of potentiality, but nonetheless ought to be understood as forming a coherent grouping, not merely analogous to one another. Rather, they are organized roughly in terms of their being different ways in which something’s abilities to bear various determinate features and exhibit different behaviors are grounded in its other persistent features. The role itself has content, he must say, though we do not fully grasp it except by way of its distinctive types of occupant. The worry is therefore relevant for Aristotle’s general approach to philosophical matters; I will return to it later (§§ 7.5 and 8.7).

7.4.  Causal Profiles at Work: Gluttonous Birds To get a more concrete sense of the way these causal profiles work, and how they may clarify Aristotle’s overall understanding of causation and causal explanation, let us take a favorable case. (It is not one Aristotle considers, but it fits his approach well, and he refers to similar phenomena in the biological works. In Part III I will turn to his own examples, focusing especially on what he says about blood in the Mete. and PA.) Suppose you have a pet bird, and over the course of a few weeks you accidentally overfeed it, so that it experiences a dramatic weight gain. There is a change to the bird—​an increase (auxêsis) in Aristotle’s sense, and a phenomenal or pre-​theoretical specification of the change would state that it is one in which the bird goes from weighing n1 grams to weighing n2 grams. To determine what kind of change is really occurring, we would look for more causal information about it—​as Aristotle puts it, we would seek to discover what the change is by inquiring as to why it has occurred. Obviously, in some

Causal Kinds and Causal Profiles  149 sense, it is caused by the fact that the bird is now taking in more calories than it burns, leading to an increase in the material being processed by the bird’s digestive system. The process by which nutrition leads to fat creation is a regular one, but it does not in this case occur for the sake of the increase that results. Considered as a whole it is, in my terms, an origin-​dominant causal process which has this increase as what Aristotle would call a necessary result. It may be decomposed into further sub-​processes, some of which will be end-​dominant and some not, such as the basic chemistry involved in breaking down food or moving it around the body. Under normal conditions of growth, of course, the processes leading to bodily increase are end-​ dominant, in that they occur for the sake of the animal’s coming to be and maintaining itself. This particular increase, however, has a distinct efficient cause, namely the change (another increase) in the bird’s caloric intake. The explanation in this case should thus ultimately go back to whatever caused the increase in the amount of food, whether it was deliberate or accidental.32 So we have a change with an origin-​dominant causal profile, many of the components of which are themselves of a type that are normally components of end-​dominant types of change and have end-​dominant efficient causes. Now consider a different bird, in the wild. Many species of migratory bird experience a dramatic weight gain as one among a variety of behavioral and physiological changes prior to migration.33 The intuitive Aristotelian explanation of the increase in weight is that the bird gains weight because it is going to migrate, or “for the sake of ” migration, which is more or less how it is still explained.34 Obviously, though, it is still true that the bird is gaining weight because it is now taking in more calories than it burns. However, the change in caloric balance in this case is part of an end-​dominant causal process, and it takes place for the sake of the increase in fat as an intermediate end, to provide sufficient stores of energy for migration; it is thus an intrinsic component of a larger, multi-​part causal process of preparation and migration. For both of these reasons, we will understandably look further, for a different or more accurate efficient-​causal origin by which we can understand 32 Thus, for the moment we can ignore the fact that fat production is itself something that in general has a teleological explanation, since we are focusing on the increase in bodily fat. Sometimes this will occur due to normal variation in availability of nourishment and sometimes due to chance variations. 33 Aristotle does not note this specific phenomenon, but he does note relevantly similar phenomena: that migratory animals are fatter when going from cold places to hot places than the reverse, so that, e.g., quail are fatter in autumn than in spring (HA VIII 12, 597a24–​27), and that some species get fatter about the time they hibernate (HA VIII 16, 600a22–​25; and 17, 600a30–​32). 34 See Pierce and McWilliams 2005 and Guglielmo 2018.

150  Causality and Causal Explanation in Aristotle the increased intake. We will, of course, still note the plain fact of the increase in caloric intake, but scientists investigating the phenomenon have also considered changes in diet and even changes in digestive processes to maximize production of just the right kind of fat for sustaining long flight.35 There will evidently be certain external or environmental triggers as well, which are relevant, but Aristotle would also think that the efficient-​causal origin in the bird itself must be more complex than in the overfeeding case, and it will be determined relative to the end of increased weight. Something in the bird’s various physiological systems is evidently controlling a complex process of preparation and migration, and in this case it is responsible for changes in nutritional and digestive processes, which may well vary between species as well as between genera—​some kinds of bat also migrate and similarly gain weight beforehand, but there are large differences in physiology not just with respect to nutrition but also flight, which evolved differently. The basic fat-​yielding process in this case is thus integrated into an end-​ dominant process, and its efficient-​causal origin reflects this. The origin of the first bird’s weight gain is a simple triggering cause which does not itself have an intrinsic efficient cause—​the bird just happened to have more food available, and the increased feeding (we have assumed) was not for the sake of promoting weight gain. The weight gain in the migratory bird not only has a different proximate efficient cause and a further final cause, but, more significantly, it has an intrinsic efficient cause of its own—​a governing efficient cause, that is, one which is actively controlling it as part of a complex process, bringing about fat-​producing changes precisely insofar as they promote fat production, and so it constitutes a different explanatory unit altogether.36 There are also, it would seem, attendant differences in the “matter” of the process, namely the various aspects of the bird’s body and digestive system, since the migratory bird must not merely be disposed to create fat with excess caloric intake, but it must be capable of taking on excess calories in response to a given internal signal. The precise specification of the form (i.e., state) 35 Guglielmo 2018, 3–​8. 36 I am here setting aside some details about how Aristotle would describe these two cases, in order to focus on clarifying the basic distinction between the two types of causal profile, though I do not think that anything I have said conflicts with what Aristotle would say. It is true that Aristotle thinks that nutritive processes in both cases, and indeed in general, involve the animal’s form as an efficient cause and, in a different way, as a final cause—​it is in virtue of its having the kind of living body it does that it assimilates food in this way, and it does so in order to develop and preserve itself as having this same kind of living body. Here, however, I am contrasting two distinct changes, one of whose efficient causes is only co-​incidentally related to the change produced, and so is not, in the example, for the sake of the resulting change in the bird.

Causal Kinds and Causal Profiles  151 that constitutes the endpoint of the process will also be different, perhaps, if the type of fat produced is different in a way that impacts the bird’s ability to migrate. (As a useful contrast, in long migrations a bird may “ingest” some of its own organ and muscle tissue for energy, and then regenerate them later.37 This process might ultimately be explained as occurring because of the extensive need for energy in migration, or as an evolutionary strategy, but not as an intrinsic part of the process of migration the way fat-​building is, unless it turns out that the birds’ organs are structured in such a way as to be easily digestible for the sake of migration.) At the stage of pre-​theoretical observation, then, the changes to the two birds are the same: they are both increases in fat (the kind of categorial description of change we described earlier). In reality, however, we do not have two phenomenally identical processes which differ only in that one of them is end-​directed and the other is not, but rather essentially different processes with different intrinsic causes. One is an instance of an origin-​dominant process, which would be defined roughly as increase in fat due to increased caloric intake. The other is an instance of an end-​dominant process, roughly defined as an increase in fat [of type(s) F1 . . . n if relevant] due to the internal mechanism which initiates various subprocesses (the ultimate starting point of the change), including the proximate changes in intake or digestive processes which result in the excess calories, by virtue of various capacities of the bird’s body to respond to these internal changes, for the sake of migration. Thus, very little about the real definitions of the two changes is the same, which reflects the fact that they are not in fact instances of the same kind of transformation. Accordingly, the difference in their causal profiles will be reflected in what we ultimately name as the exact cause of weight gain in these and other individual cases. In this way, determining the causal explanation of why things happen as they do is at the same time a matter of specifying just what kind of changes they are, and on the Aristotelian approach we do this in part by applying a causal profile of the type I have described. This type of case also illustrates an important general possibility, important both for its metaphysical and epistemological implications: two changes might have the same pre-​theoretical account (specified by its endpoints alone) but turn out to be different kinds of change altogether, with different theoretical definitions.



37 Battley et al. 2000.

152  Causality and Causal Explanation in Aristotle

7.5.  Implications for Puzzles about Aristotelian Causality I have argued that Aristotle’s metaphysical causal pluralism is a commitment to the view that the question of how a thing relates to its causes does not admit of a single answer within any of the modes, or even a single answer-​ schema for the various kinds (natural or artificial) which are distinctive in having intrinsic causes. In some contexts and in some ways the main point might seem obvious, but appreciating the importance of these distinctions among causal profiles allows us to understand Aristotle’s philosophical position with greater clarity, and to re-​evaluate some familiar claims and puzzles raised about it. In a way, the importance of recognizing distinct causal profiles is of a piece with Aristotle’s general “bottom-​up” approach to basic questions. I would suggest that while he does not give a general definition of ‘cause’, his glosses on the different individual modes of causation have the same status as his well-​known account of soul (psuchê) from DA II 1. As he says, the account of soul as “the first actuality of a natural organic body” (412b5–​6) is a schematic account, informative and important, but it cannot be taken to be—​and is not meant to be—​a definition in the strict sense, since the more determinate natures are themselves different enough that appreciating how the general account applies to any given type of life or soul does not really constitute understanding that particular type of life or soul (414b20–​34). Likewise, I think, he is committed to the view that simply understanding that different sorts of transformation all depend on matter for their very possibility does not amount to understanding, for any particular type of transformation, just how something’s ability to undergo that transformation is explained by its matter, or indeed, exactly what the underlying matter is. This is not a skeptical or anti-​metaphysical position, since there are broad divisions that in turn apply to many lowest-​level species of change. Just as Aristotle thinks that the distinctions between nutritive, perceptual, and intellectual soul are explanatorily more fundamental than the general notion and do quite a bit of explanatory work—​they are not mere placeholders on the way down to determinate particular species—​so the distinctions among the different types of causal profile are not simply placeholders either, but mark explanatorily important types. Further, acknowledging these causal profiles is a crucial part of Aristotle’s explanatory anti-​reductionism. The way to understand any causal explanandum is, on this view, to discern whether it has intrinsic causes, and if so,

Causal Kinds and Causal Profiles  153 just what they are, of which types, and how they relate to each other. Most explananda will also bear causal links—​even intrinsic causal links—​to other kinds: indeed, there are regular types of dependencies across these kinds of profile: transformations are generally for the sake of beings, and beings are generally defined in terms of activities. There are thus chains of dependency terminating in ontologically fundamental beings (i.e., substances) as principles or archai, which have a claim to being causally basic or immediate. But part of Aristotle’s point is that we can distinguish between having a genuine causal explanation for any among a wide array of causally explicable phenomena, on the one hand, and having an explanation that appeals directly to some basic entity, on the other. Even if, for all of nature to be fully intelligible, everything we explain must somehow ultimately be connected to something causally and ontologically basic, it is a mistake to think that something must be directly related to some such basic entity in order to be intelligible. Indeed, connecting something to basic principles too directly is a major defect of his predecessors’ reductionism: it is the source of the mistaken appearance of understanding that derives from focusing too narrowly on ultimate causes—​ things that are somehow just what they are in virtue of themselves alone—​ and ignoring a phenomenon’s intrinsic causes. Recognizing that causal explanation of natural things divides into a series of intermediate profiles also, I think, helps clarify the nature and status of certain other commitments of Aristotle’s which are often subjects of puzzlement or controversy. One is the so-​called Principle of Causal Synonymy (PCS)—​the claim that a cause of F-​ness must itself be F—​which is often attributed to Aristotle.38 An especially clear statement that seems to affirm the PCS comes in Met. XII 3: “Next [note that] each substance comes to be from something synonymous” (1070a4–​5). The passage itself is only directly about the generation of substance, and as commentators have noted, there are many qualifications Aristotle would place on such a principle even on the strongest reading of his commitment to it.39 Still, it can seem from many presentations that Aristotle accepts the PCS as a kind of a priori principle about causality as such, while 38 This “principle” is related to and often assimilated with the notion of a “transmission” theory of causality, which is different: one might have synonymy without transmission (as in the Phaedo), and Dowe 2000 defends a transmission theory appealing to conserved quantities rather than property identity. 39 Cf. Met. VII 9, 1034a21f. Another case that seems to fit the PCS is the account of alteration given in GC I 7, according to which agent and patient have different qualities in the same genus, e.g., temperature, such that the patient is assimilated to the agent.

154  Causality and Causal Explanation in Aristotle noting a number of exceptions or qualifications.40 Aristotle does not, however, ever present the PCS as a general claim about causality, and in some important instances denies outright that it holds as a general or conceptual matter with respect to causality.41 This is most obviously the case for the kind of mediated causal claims characteristic of the basic APo. schema, according to which universal causes explain the predicational tie between some further predicate and its subject—​in general and as a conceptual matter, the causal middle term is distinct from the major and minor terms, and cases where there is an essential connection among terms are exceptional.42 For example, we prove that the planets (C) do not twinkle (A) because they are close (B) (APo. I 13, 78a39–​b4). Moreover, the point which directly follows the initial presentation of the four causes in the Physics—​that there are multiple ways of being an intrinsic cause of F, where Aristotle emphatically points out that the causes of a statue are all causes of it as a statue and not as anything else it may be (195a3–​8)—​is itself a rejection of the principle in its 40 See, e.g., Lloyd 1976; Mourelatos 1984; Bodnar 2018; and Byrne 2018. In some presentations (e.g., Byrne 2018, 26), the content of the principle seems to be diluted to the anodyne thought that a cause must be “such as” to produce a given effect. 41 The passages just noted—​Met. VII 9, 1034a21f.; and XII 3, 1070a4f.—​contain probably the strongest statements of something like this principle but are in fact rather weak in scope and nature. In both cases (more clearly in VII 9) it appears to be a premise in an argument, recording a general fact about how natural and artificial things come to exist with the aim of showing that forms do not come to be, rather than a consequence of any general principle about causation. Likewise, in GA II 1, 734b19–​735a4, the claim is restricted to the production of ensouled (functionally defined) parts and artifacts, which are distinguished from the way non-​functionally defined properties like hardness and stickiness are produced in living bodies. Another passage often cited is Phys. III 2, 202a9: “the mover will always bear (oisetai) a certain form”; but the passage is about movers, not causes full-​stop, and ‘transmit’ is an overtranslation of ‘oisetai’ (e.g., Hardie and Gaye in the Revised Oxford Translation; cp. Hussey: “will always carry”; Reeve: “is always the bearer of some form”). Cf. Tuozzo 2014, 30 n. 18. Met. VII 7, 1032b11–​14, appears superficially to affirm something similar, but there Aristotle’s statement is just that practical reasoning starts from the end that production brings about, so that “in a way” (tropon tina) health comes to be from health, etc. Finally, we might initially think that the PCS is expressed in the well-​known passage in Phys. II 7, 198a24–​27, which states that the formal, final, and efficient causes often “arrive at” (erchetai) or refer to the same thing. Here again, however, the qualifications in place show that Aristotle is making an assertion about a special case, not offering a principle about causality in general. This convergence is only asserted to happen “often” (pollakis), not always, and the passage is explicitly concerned with how, in studying natural kinds, i.e. things that have internal principles of change, one “leads explanations back” (anagetai, 198a16–​18, a22, a32) to ultimate (eschaton, 198a16–​18), in contrast to proximate, causes. Thus, the emphasis is again on a special feature we find in determining the ultimate starting points for explaining natural kinds, not a general thesis about intrinsic causality. See also Phys. VIII 4, 254b12f. for explicit claims that intrinsically caused (kath’hauta) changes includes both changes that occur by nature and those that occur by force (biai) and against nature (para phusin). I discuss this passage about convergence further immediately below, as it pertains to claims about formal and final causes being “one” or “the same.” 42 Even where there is an essential connection between the middle-​term-​as-​cause and the effect it explains, as between interposition of the Earth and a lunar eclipse, there is no suggestion that it is somehow because interposition satisfies a rationalist principle of this sort that it is suited to be a cause of eclipses.

Causal Kinds and Causal Profiles  155 unqualified form. We should further note that, after discussing basic cases in which an agent assimilates a patient to itself (e.g., hot things heating other things), Aristotle qualifies this point by saying “what is hard does not come to be from what is hard” (GC I 5, 320b21), and when he does this, he is not simply noting a minor exception.43 The vast proportion of the reactions described in Meteorology IV are defined in terms of endpoints of hardness and softness, and he says that these are the primary affections (pathêmata) with respect to the various type of interaction between hot, cold, moist, and dry (IV 4, 382a8–​11).44 Saying that hardness is not caused by hardness removes a whole range of important natural phenomena from falling under a purported synonymy principle. Considering all the different ways in which there are intrinsic causal profiles for various sorts of natural and artificial phenomena, however, it becomes even clearer that Aristotle does not at all accept as a necessary conceptual condition that “only something F can be a genuine cause of F-​ness in something,” as Plato and neo-​Platonists seem to do.45 It seems instead to be an evident fact about what Aristotle takes to be some of the most fundamental beings—​substances, some basic kinds of alteration among the elements, and forms of knowledge—​that they derive from and give rise to things of the same sort, and in this way represent the most stable eternal regularities in nature. If this expresses a principle, it is not an a priori claim about causality but rather a commitment to the thought that ultimate reality and persistence over time approximating eternality go together. But the PCS cannot, for Aristotle, be a premise in an argument to the effect that, for example, some candidate X cannot be an intrinsic cause of F-​ness because X is not itself properly speaking, or even loosely speaking, F. In general, then, the idea that Aristotle is committed to a PCS is another result of overextending the features of special cases, in this instance phenomena with a special status and a specific causal profile which he thinks does exhibit synonymy, but not for reasons having to do with causality in general. Distinguishing these different profiles also allows us to clarify Aristotle’s frequent and somewhat cryptic claims that the formal and final causes are 43 Retaining the sentence, which is present in all the MSS, along with Rashed 2005 and Reeve 2023, against Joachim 1922 (who thinks it should be moved or deleted) and Williams 1982 (who deletes it). 44 “Among the bodily affections (pathêmatôn) these primary ones belong necessarily to what is defined: hardness and softness; for it is necessary for what comes from what is dry and moist to be either hard or soft.” 45 For a classic treatment of the principle, see Lloyd 1976.

156  Causality and Causal Explanation in Aristotle often or sometimes “the same” or “one.” The most well-​known and contextually salient is perhaps from Phys. II 7: “But the three [causes] often refer to one; for the what-​it-​is and that-​for-​the-​sake-​of which are one, and the primary thing from which the change comes is the same in species as these; for man begets man—​and in general whatever brings about a change (hosa kinei), being changed itself ” (198a24–​7). These claims are especially puzzling, since it is not evident, for example, whether Aristotle is making a metaphysical claim about two entities somehow constituting a unity, in which case it is not clear how they are different or what unites them, or about multiple roles all being occupied by the same thing, in which case it is not clear how the different roles can be occupied by a single thing without sacrificing some degree of explanatory power.46 In fact, Aristotle makes a variety of such “sameness” claims, and in different contexts they amount to different things. When he is focusing on transformations such as generation and change, which typically have three-​ component profiles, it is natural for him to specify that the endpoint—​that is, what occupies the role of “that for the sake of which” the transition occurs and proceeds as it does (along with whatever sub-​processes it has)—​is the same thing as that which occupies the role of form in the completed being (relative to which it is part of a different causal profile). But this is not at all to say that there is one entity that occupies two causal roles with respect to the same explanandum, or that two entities are in some special sense the same.47 The following passage from De Anima, however, cannot be read in the same way, or at least not just this way: The soul is the cause and principle of the living body. These [sc. ‘cause’ and ‘principle’] are said in many ways, and likewise the soul is a cause in accordance with three of the ways that have been distinguished; for the soul is the cause as that from which the change comes, and as that for the sake of which, and as the substance of ensouled bodies. Now, that it is the cause as substance is clear: for substance is the cause of being for everything, and to be for living things is to live—​and the soul is the cause and principle of this. Further, the actuality is the account of what is in potentiality. And it is clear

46 These claims are rarely the focus of direct discussion, as opposed to clarifying comments on particular instances in the context of other issues; but see Stein 2018, § 4, and notes there, as well as Cooper 1982, 200–​202; and Rosen 2014. 47 Passages that can be read this way include the canonical claim in Phys. II 7, 198a24–​27, as well as GC I 7, 324b17; and GC II 9, 335b2–​7.

Causal Kinds and Causal Profiles  157 that the soul is also the cause as that for the sake of which; for just as mind (nous) acts for the sake of something, in the same way nature does so as well, and this is its end. And in accordance with nature, the soul is this sort of thing for animals; for all the natural bodies are instruments (organa) of the soul, and just as they are for animals, so they are for plants as well, being for the sake of the soul. But ‘that for the sake of which’ is said in two ways, both that of which and that for which. (II 4, 415b8–​21)

Here Aristotle is focusing on the hylomorphic relationship between the soul and the living, tool-​like “organic” body.48 In the first part of the passage he may indeed be alluding to generation by referring to the fact that nature “acts for the sake of something,” that is, in this case for bringing about a hylomorphic living substance, but at the end of the passage he claims that natural bodies (phusika sômata) are instruments of the soul (psuchês organa), referring us to his distinction between two senses of “that for the sake of which”—​the so-​called end-​genitive and end-​dative mentioned earlier.49 Here the point, I think, is that it is in virtue of the unified soul that an organism is capable of exercising various life activities (soul as formal cause), but the various parts of the ensouled body are also as they are for the sake of the organism’s being of that sort—​that is, they are present and structured as they are so as to constitute the grounds of the organism’s capacities or to promote the activities characteristic of that sort of life (soul as final cause). Once again, then, there is a shift of explanandum, so that one entity, the soul, is occupying two different roles with respect to two different explananda, however closely they are related: (1) On the one hand, as substance (form), the soul is the cause of life by constituting with the matter as a whole a particular living thing, whereas (2) as an end, the soul explains the features of the body, especially its parts.50 Thus, here again the profile matters: we are not specifying form’s role in both a process of generation and 48 The nature of that relationship, both in general and with respect to specific mental capacities such as perception, is one of the most discussed and contested in recent scholarship. For some recent starting points, see Menn 2002; Johansen 2012; and Charles 2021. 49 See § 5.1. 50 There are several possibilities for understanding the claim that the soul is a cause of the body and its parts as “that for the sake of which,” including the thought that he is referring to the development (i.e., generation) of the body—​this is encouraged by the comparison between mind’s acting for the sake of something and nature’s doing so. The claim that natural bodies are tools of the soul, on the other hand, encourages the thought that Aristotle is referring to the fact that the body is structured in such a way as to enable the living being to actualize the capacities constitutive of being ensouled. The readings are not exclusive of one another, and on either reading the explananda in the two instances (soul as substance and as final cause) are clearly different.

158  Causality and Causal Explanation in Aristotle in the complete being that results, but rather, or in addition, the relation of the soul to further causally explicable regularities about the body besides its simply constituting a kind of living thing. The situation appears to be reversed, however, in the well-​known passage from Met. VII 17 which we have already discussed: Therefore one is inquiring why something belongs to [i.e., is predicated of] something. (That it does belong to it must be clear; for if it is not thus, one is not inquiring about anything.) For example, why does it thunder? Why does noise come to be in the clouds? For this way what is sought is one thing holding of something else. And why are these things, e.g. bricks and stones, a house? It is evident then that one is inquiring after the cause; but this is the essence, to speak in the abstract, which for some things is what it is for the sake of—​for example, perhaps for a house or a bed—​while for others it is what first brought about the change; for this is also a cause. But this sort of cause is sought for generation and destruction, whereas the former is also sought with regard to being. (1041a24–​32)

Here, Aristotle asserts that it is “that for the sake of which” that can occupy the role of essence, rather than that the form, which normally occupies the role of essence, can occupy the role of final cause (either with respect to generation and change or with respect to the body). Once again, the causal profile matters—​indeed, as I have suggested, Aristotle is here describing different profiles in the abstract: we are not attempting to explain the occupants in the nature of a transition or the elements of a causally definable compound, but rather the relationship among the various intrinsic causes, insofar as some things can have an efficient cause as their essential primary cause, that is, the primary cause by which the form belongs to the matter, while in other cases this is the final cause. None of these passages, then, describes any special metaphysical unity or commits Aristotle to there being multiple explanatory patterns between the same two entities; rather, they shift between different explananda and different causal profiles. Now, Aristotle does think, of course, that there is a special relationship between form and activity (i.e., function or “work”); this is expressed in his homonymy principle (something that cannot fulfill the function of being an F, where F has a function, is not an F except in name, i.e., by courtesy), and in his view that “what is in potentiality and what is in actuality are somehow

Causal Kinds and Causal Profiles  159 one (hen pôs)” (Met. VIII 6, 1045b21).51 This relationship may be what is indicated in a passage from Met. VIII 4: “What is the form? The essence. What is the cause in the sense of that for the sake of which? The end. But perhaps these are both the same” (1044a36–​b1). After all, the aim of that book is ultimately to claim that there is no special cause of unity in a natural substance, and Met. IX goes on to develop the identification of form with actuality, that is, activity.52 These claims, too, however, must be understood with reference to the explanandum at issue. Aristotle is not, in these passages, discussing generation and change in general, but rather attempting to get a grip on the nature of form itself and its relation to matter and activity, with a focus on the special case of living beings. The metaphysical claim seems in essence to be a claim about unity: roughly, the idea is that a thing’s form, in the case of complex substances, is a unity primarily with reference to the activities it grounds—​ we cannot get an independent grip on what it is to be a gazelle or a gazelle’s heart, or how they have any unity of their own, for example, except by reference to what makes them capable of engaging in the animal’s life activities.53 There are thus a variety of unity claims that Aristotle makes with respect to formal and final causes, especially with respect to living substances. Some of them stand on their own, as, for example, the relatively straightforward claim that the end-​state of a transformation is the same as the formal feature of the being in which it results. They may well all be ultimately connected, 51 For the homonymy principle, see Mete. IV 12, 390a10–​13; DA II 1, 412b20–​22; PA I 1, 640b33–​ 641a5; GA II 1, 734b24–​27; Pol. I 2, 1253a18–​25. The principle has been the subject of a great deal of discussion in the context of “Ackrill’s problem” for the hylomorphic account of the relationship between soul and body. For the close connection between actuality and potentiality, see, e.g., Met. IX 9, 1051a29–​30 (what is potential is discovered by being brought into actuality). In Met. IX, Aristotle claims at 1050a9 that “the end is the actuality, the capacity is acquired for the sake of this”; then, half a Bekker page later, he concludes that “thus it is clear that substance, i.e. form, is actuality” (1050b2), where by ‘actuality’ he clearly has in mind the relevant end. By transitivity, it seems, we ought to conclude that the form, in some sense, is actuality, conceived of as activity, despite (or in addition to) the prima facie case for thinking of form as the ground of activity. The two aspects of this relationship are, of course, closely connected; indeed, DA II 3, 412b18–​20, which leads into the expression of the homonymy principle, states that for ensouled bodies, their substance is their activity: “if the eye were an animal, its soul would be sight; for this is the substance (ousia) of the eye in accordance with the account.” Likewise, in the controversial account of perception in DA II 5, he asserts that, insofar as perception is a transition from first to second actuality, analogous to the transition between knowing something and thinking about it, perception is not to be considered a change in the strict sense. 52 Then again, this may be a case in which it is wrong to assume ‘essence’ and ‘form’ are interchangeable. 53 This sketch is, of course, far too brief to do justice to the many issues surrounding Aristotle’s accounts of life, substance, and soul, but it is enough to make it clear that this special relationship, where Aristotle indicates it, is only one way in which it may makes sense for Aristotle to describe formal and final functions as somehow “one” or “the same,” and perhaps not the typical case.

160  Causality and Causal Explanation in Aristotle of course, if the nature of form as actuality is in turn related to the idea that the soul constitutes a generated substance capable of various activities which are, in turn, exercises of the various parts and features of its body, and that generative processes occur as they do for the sake of bringing about such hylomorphic compounds. It is no accident, perhaps, that Aristotle seems to run them together. They are different claims, however, most of which are plainly comprehensible without reference to any special metaphysical commitments about the teleological nature of form or substance, and which can be distinguished from one another by reference to the causal profiles at issue.

7.6.  Summary A further component of Aristotle’s answer to the question of how a thing relates to its causes, then, is that different types of phenomena have different causal profiles, where these are structures that characterize different sub-​ classes of causally defined phenomena. One key distinction that governs them is that between what I have called origin-​dominant and end-​dominant causal profiles: in the former, the efficient cause has priority, while in the latter the final cause has priority. There are potentially a wide variety of different causal profiles, depending on the number and type of causes pertinent to the different types of phenomena which the natural scientist aims to understand. That variety itself has some primary divisions, however, reflecting key patterns that characterize the specific types of transformation, being, and activity that have primacy in nature. These depend especially on the number and type of relevant causes, and whether all or some of them are intrinsic. For example, Aristotle’s common example of the eclipse has an origin-​dominant causal profile, but one in which the material cause is not intrinsic to the explanandum, whereas the types of basic chemical changes described in the Meteorology and discussed in § 6.4 also have origin-​dominant profiles but have all of their causes intrinsically. Different types of causally defined kinds likewise have distinct causal profiles, such as the following: among transformations, the changes that result in essential properties, generative processes, transformations resulting in non-​essential features, and generations of substances; among beings, intrinsic features, the parts of wholes, and natural substances as such (i.e., as distinct from the processes by which they come to be); among activities,

Causal Kinds and Causal Profiles  161 those in which the end is internal to the activity, and those for which the end is external. These distinctions among different causal profiles in turn correspond to points at which Aristotle finds it necessary to distinguish uses or senses of key terms, such as matter, principle (archê), or actuality (energeia). For certain natural kinds, these profiles connect to one another almost seamlessly, as for living beings which are generated and are structured as they are for the sake of certain kinds of activity. These are special cases, however; in principle and in fact for certain cases, these profiles can be realized independently of one another, and an inquirer cannot assume at the outset what kind of profile a given causal phenomenon will have. This pluralism is of a piece with Aristotle’s “bottom-​up” approach to metaphysical questions and to questions about definition in general, but it is not a skeptical or anti-​metaphysical position, since there are broad divisions and explanatory connections at different levels of generality. A key part of it, however, is that we can and should distinguish between (1) the demand that the scientist who seeks to understand the natural world must show how natural phenomena are ultimately connected to the most basic entities or principles, which Aristotle seems to accept, and (2) the claim that any particular natural phenomenon can only be explained in its own right by connecting it to a basic entity or principle, which he rejects. Recognizing causal profiles also helps us resolve certain more local puzzles about Aristotle’s account of causality, including his attitude toward the so-​ called Principle of Causal Synonymy, and his various claims that formal and final causes are ‘one’ or the same.

8 Discreteness in Agent–​Patient Relations 8.1.  The Realist Question I have argued so far that for Aristotle, causal explanation involves understanding not just the intrinsic causes of each causally defined kind, but the nature of their relationships to each other and to the explanandum itself—​ what I have called their causal profiles. Not all profiles involve all four types of cause, and in different profiles a different cause may be primary—​one particularly important distinction being between what I have called origin-​ dominant and end-​dominant profiles. These causal profiles, in turn, reflect and are reflected in the actual types of metaphysical relationship that answer to the second-​order roles which correspond to the canonical distinctions between four types of cause. Aristotle does not systematically develop either of these aspects of his theory, perhaps because much of what he does is aimed precisely at working out and understanding these differences, but they represent, I think, the main articulations of the view he is developing. How, then, does the theory fare with respect to the philosophical questions about the metaphysics of causation raised earlier (§ 5.2), both as a response to his predecessors and in general? The view has an important philosophical virtue in relation to Aristotle’s rejection of his predecessors’ explanatory reductionism. By locating the primary cause of a thing’s being what it is within its peculiar causal profile, Aristotle has in effect separated the question of a thing’s primary cause from the question of its relationship to something that is causally primary. Aristotle clearly thinks that in order for a domain to be fully intelligible, we must ultimately be able to connect the various objects of understanding in that domain to causally basic entities or principles, but by attempting to do this too quickly, we in fact fail to explain what we set out to explain—​this is one of the main defects of explanatory reductionism. Some things are indeed fundamental—​they are just what they are all by themselves—​or are very closely related to causally fundamental principles. Most things, however, are not: they are what they are in part by themselves and in part by virtue of their Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0009

Discreteness in Agent–Patient Relations  163 relation to other things, which may in turn be at several removes from whatever entities or principles are fundamental to their domain. There is more to be said, of course, about how this type of metaphysical pluralism can respond to the kinds of reductionism Aristotle wishes to reject. However, it will be more fruitful to return to that topic after addressing the epistemological questions raised in the next section. On the other hand, we might once again question at this stage whether the view really says anything directly pertinent to the metaphysics of causality, besides its commitment to pluralism, especially about efficient causation, or whether it is instead either deliberately or implicitly mute about metaphysics. Indeed, a reductionist might argue that Aristotle has substituted one project for another: rather than explaining natural regularities in terms of causally basic entities or relationships, he is instead offering us finer-​grained type-​ level descriptions of those regularities, as well as a complicated picture of ways in which they may inter-​relate and form explanatory chains which terminate in basic entities. Rich as this picture may be, it is fundamentally a descriptive project, not an explanatory one. Indeed, by attempting to explain even non-​basic phenomena by reference to a statement of “what they really are,” Aristotle has robbed external causes of the explanatory power they might otherwise have had, by incorporating them into the nature of the phenomenon itself—​it looks a bit like simply stipulating that to be an F of this sort just is to be brought about by that sort of thing. It is fair to ask, then, what the relationship is between cause and effect in a given or especially important case. Arguably, a sound analysis of transeunt-​ causal interactions particularly is required if we are to give efficient causes the prominent role in natural science that Aristotle assigns them, and to defend their explanatory power, especially if he is willing to say so much about the metaphysical relationships between natural beings and their form, matter, and ends—​however obscure some of it may be. Focusing on the features I have described earlier as problematic—​discreteness, contingency, and non-​ accidentality—​we should ask, then, whether Aristotle offers or is committed to any sort of account of the efficient-​causal nexus, at least in basic cases of interaction, that addresses the tension between them. As I have suggested, Aristotle needs to account for these features anyway, in order to make his case against his predecessors, and he is sensitive to them, even if he does not confront them directly. Nevertheless, it is not a straightforward matter simply to ask whether he thinks causal relations of whatever sort manifest discreteness,

164  Causality and Causal Explanation in Aristotle non-​accidentality, and contingency, since he does not speak in these terms, nor are they precise by themselves—​at least, they are in need of disambiguation. In one sense, Aristotle’s commitment to contingency is obvious enough, insofar as he takes the entire domain of nature to be the domain of contingent matters: of what comes to be, and so may in some sense “be or not be.”1 This is not as superficial as it seems, since transformations are analyzed in terms of matter and potentiality, and he thinks that the conditions under which a given potentiality is actualized need not occur at any given time, even if, when those conditions are satisfied, the change must result. So nature is the domain not just of what is logically contingent but of things that are physically constituted in such a way that their various potentialities may not be actualized, and that even when they are, what they yield is only temporary.2 Aristotle also recognizes two further sources of contingency in natural affairs: essences may be imperfectly realized, and some causal processes are initiated by co-​incidence. Thus, even if certain substances and transformations have causal essences, they may be interrupted or fail to unfold in their characteristic way for various reasons.3 Likewise, if a plant suffering in a drought receives water from a leaky cistern, it will grow, since the intrinsic causes of its growth can arise by co-​incidence. These sorts of contingency will not satisfy someone worried about universal causal determinism, but Aristotle is notoriously not worried about it, whether or not he should be.4

1 GC II 9, 335a32–​b5. 2 There is a dispute about whether Aristotle subscribes (in at least some contexts and for apparently independent reasons) to the so-​called Principle of Plenitude, which implies that every possibility will be realized at some time or other, but this is a different and controversial point, which clearly does not prevent him from thinking that some things have capacities they in fact never actualize; see Denyer 2000 and Makin 2006, 82ff. His use of modal terms and concepts is complex in other ways, including in his well-​known and controversial arguments related to necessity and time (De Int. 9), and his association of what is always true or eternal with necessity (DC I 12 is much discussed, but cf. especially GC II 11, 337b35–​338a3, PA I 1, 639b24). He takes biological species to be eternal, and so necessary in some sense; on this claim see Lennox 1985. See especially Met. V 5 for his basic distinctions among types of necessity. 3 With regard to Aristotelian substances, such failures are traditionally ascribed to the matter, but the interpretation is controversial; cf. especially Met. VI 2, GA IV 3, as well as Gill 1989, 166. More broadly, Aristotle describes many natural phenomena as occurring the way they do “for the most part” (hôs epi to polu), associating these with what occurs always or necessarily or without qualification (haplôs), in contrast to what occurs, not by nature, but co-​incidentally (which includes, of course, what occurs “by luck,” apo tuchês, or “by chance,” apo tou automatou, as he understands the terms). At Phys. II 7 198b6, he seems to include “for the most part” under necessity (alongside what occurs without qualification), but it is more common for him to distinguish them, as at Phys. II 5, 196b20; Met. V 30, 1025a20; and Met. VI 2, 1027a10. For a classic discussion of these distinctions and their importance, see Judson 1991. 4 On this question, see D. Frede 1992.

Discreteness in Agent–Patient Relations  165 As we have also seen, Aristotle is at pains to show that a natural kind’s causes are not co-​incidental to it, since he thinks this result is a major defect of his predecessors’ views, but rather intrinsic. He satisfies “non-​accidentality”—​ in the sense described earlier in my discussion of the demands of a realist approach to causality in § 5.2—​in slightly different ways for different causal profiles, as we can see especially in light of the difference between origin-​ dominant and end-​dominant profiles. His view thus aligns with those aiming to secure a notion of special connection between cause and effect without relying directly on the notion of laws of nature. The more philosophically challenging concept, for Aristotle as for philosophers in general, is discreteness, which he highlights in some respects in his criticisms but does not really address directly. We can test his view, however, by applying various distinctions that have been and may be drawn with respect to discreteness, since these have been the subject of a good deal of clarification in recent work. What is helpful about these distinctions, I shall argue, is that they nicely reveal the different types of relationship between a thing and its causes that Aristotle in fact wishes to affirm, and so allow us to capture the way in which he hopes to give causal explanations that respect all of these metaphysical properties, but without appealing to a special ontology or privileged relationships to such an ontology. Before we apply those distinctions to Aristotle’s understanding of transeunt-​causal change, however, we must clarify what Aristotle says about the structure of such changes, since in a number of passages he attempts to be precise about how we should describe efficient causes and what they cause. This requires looking at two main passages: in Phys. II 3 Aristotle draws an important series of distinctions between various “ways of being causes,” while in Phys. III he clarifies the nature of change considered as the actuality of agent and patient.5

8.2.  “Ways of Being Causes” in Physics II 3 The final part of Phys. II 3 (195a26–​b30), as we have seen, runs through a variety of “ways of being causes,” drawing several distinctions and giving instructions for citing causes. They seem on the whole to be an attempt to 5 Agent–​patient relations are further discussed, from another perspective, in GC I 7–​8, the argument of which will be relevant at points later.

166  Causality and Causal Explanation in Aristotle arrive at the most appropriate or accurate way to specify causes and effects, and though Aristotle initially presents them in fully general terms, he focuses, for reasons that are not obvious, on efficient causes: [195a26] So then, the causes are these and they are this many in form; but the ways of being of causes are many in number, though these too fall under fewer groupings. For cause is said in many ways, and among those of the same form one is prior and another is posterior: for example, of health, the doctor and the expert, and of the octave, double and number, and always what is inclusive in relation to the particulars. Further, [they are spoken of] as what is co-​incidental and its genera, for example of a statue, in one way Polycleites and in another way the statuemaker [are causes], since being for Polycleites co-​incides with the statuemaker. Also, what is inclusive of the co-​ incidental, for example, if the man is the cause of the statue, or [speaking] generally, animal. Among the co-​incidents, also, one is farther away and another is nearer, for example, if the pale man and the musical man were said to be the cause of the statue. And for both all the things called [causes] properly speaking and those that are [so-​called] co-​incidentally, some are spoken of as being potential and some as being in activity, for example, of a house’s being built, the housebuilder or the building housebuilder. Those things of which the causes are causes for the things described will be spoken of in the same way, for example of this statue [they are called causes of] either a statue or in general an image, and of this bronze either of bronze or generally of matter; and similarly for the co-​incidents. [195b10] Further, each of these will also be stated in combination, for example, neither ‘Polycleites’ nor ‘statuemaker’, but rather ‘Polycleites the statuemaker’. Nevertheless, all these are six in number, though spoken of in two ways; for they are spoken of either as (1) the particular, or as (2) the genus, or as (3) the co-​incident, or as (4) the genus of the co-​incident, or as (5) these in combination or (6) simply. And all of them are either [spoken of] as being (7) in activity or (8) with respect to potentiality. They differ by this much, that the things that are in activity and particular are and are not at the same time as those things of which they are causes; for example, this healing-​ person as that person-​being-​healed, and this building housebuilder as that house being built, whereas those that are in potentiality are not always [co-​existent]. For the house and the housebuilder do not perish at the same time.

Discreteness in Agent–Patient Relations  167 [195b21] [Injunction 1] It is always necessary to seek the topmost cause of each thing, just as with other things (for example, the man builds because he is a builder, and he is a builder in virtue of the craft of building;6 this, then, is the prior cause, and [we should seek] this way for all things); [Injunction 2] further [we should seek] genera [as causes] for genera, and particulars for particulars (for example statuemaker for statue, but this [statuemaker] for this [statue]); also, potential [causes] for potentialities, and active ones in relation to things being actualized. Let this suffice for us to distinguish what things are causes and in what way they are causes.

It is important to clarify what this passage does and does not do, not only because these distinctions and injunctions are important for understanding efficient causes, but also because some of them have been cited as holding especially important clues about Aristotle’s overall conception of causes in general or of efficient causes in particular. The list itself is a somewhat strange mix of distinctions: it is unclear how much of it is primarily metaphysical and how much is really about ways of referring to causes. (Of course, Aristotle often couches metaphysical claims as claims about how things are to be described, so we must be careful with such appearances as well.) The first pair distinguishes intrinsic causes into (1) prior and (2) posterior, where the subsequent passages make it clear that priority is assigned to what is more particular or determinate: “the doctor” is prior to “the expert.” (3) and (4), particular or generic co-​incidental causes, mirror the particular/​ general distinction but refer to the cause using terms which do not indicate 6 The phrase “he is a builder in virtue of the craft of building” (“ho d’oikodomos kata tên oikodomikên” (195b23–​24) presents some difficulty, since ‘the craft of building’ seems to imply generality in a potentially misleading way. It is the builder’s craft-​knowledge that is the prior cause being referred to, rather than the craft as such. Most commentators accept that this is indeed what Aristotle is referring to, but it is on the basis of this passage and a handful of others that M. Frede argues that Aristotelian efficient causes cannot be conceived of as active, any more than “ends, forms, and matter” (126; the interpretation is discussed in this section). One could translate ‘tên’ possessively (along with Hardie and Gaye in the Revised Oxford Translation) to emphasize that Aristotle is referring to the individual builder’s craft-​knowledge, but this might make it seem misleadingly peculiar to the individual builder—​craft-​knowledge is a transmissible universal form, like all knowledge. Stylistically, the possessive may be more natural, since Aristotle is already describing an individual builder, and he immediately distinguishes generic specifications of causes from more determinate ones, saying that we should specify individual causes for individual effects. The term ‘kata’ can also be translated in different ways: some use ‘in virtue of ’ (e.g., Hardie and Gaye again, as well as Reeve 2018); others ‘in accordance with’ (e.g., Charlton 1992). The second translation is often more appropriate, and it need not simply mean that the builder is following the rules of building: Aristotle’s famous eudaimonistic claim in the NE is that the human good is an activity of the soul ‘kat’ aretên’, which is fairly interpreted as referring to an expression of one’s excellence rather than simply exemplifying or “tracking” excellence. Nevertheless, however we translate ‘tên’ and ‘kata’, the subject of the phrase and of Aristotle’s concern is still the individual builder-​as-​such.

168  Causality and Causal Explanation in Aristotle that aspect of it by which it is an intrinsic cause of the effect, as when we refer to the doctor as “that man” or “a man” or “a mammal.”7 Finally, (5) and (6) reflect the fact that we can refer to a cause using both a co-​incidental description (i.e., co-​incidental relative to its causal aspect) and an intrinsic causal description together: in this context, the first term in ‘Polycleites the sculptor’ is co-​incidental.8 Particularity and generality are clearly meant to track metaphysically salient properties, especially since particularity is allied to priority; likewise for the distinction between co-​incidental and intrinsic causes, and between actual and potential causes. However, the fact that we can combine an intrinsically causal and a co-​incidental feature into a single phrase does not seem to introduce any new metaphysical point. Less clear, and more controversial, is the status of the injunction to seek the “topmost” cause. Many commentators interpret it as expressing an important metaphysical claim to the effect that strictly speaking, in this example, “the craft of sculpture” is the intrinsic efficient cause of a given particular sculpture, rather than, say, the sculptor. Some have gone so far as to argue on the basis of this passage and one or two others that Aristotle’s efficient causes cannot be conceived of as efficient causes in “our” sense, because the craft of sculpture is not a thing that does something or other so as to bring about an effect—​it is not “active.”9 Most commentators do not go quite so far, but many nonetheless take Aristotle to be making a metaphysically significant

7 As previously noted, it sounds odd for Aristotle to use ‘man’ to indicate something co-​incidental to a person like Polycleites, but the point here is that Polycleites only happens to be a sculptor, and it is only qua sculptor that he is an intrinsic cause of a statue; qua man, by contrast, he would be an intrinsic cause of his children. 8 Aristotle also notes that the co-​incidents (i.e., the features of a given thing that are not specific to the relevant explanandum) are many and can be more or less remote: Polycleites’s being a man is co-​ incidental to his being a sculptor, but clearly more closely related to it than his being from Argos. 9 Most influentially, perhaps, see M. Frede 1980: “Quite generally our use of causal terms seems to be strongly coloured by the notion that in causation there is something which in some sense does something or other so as to produce or bring about an effect. . . . Thus, though we may want to get away from such a notion, there is a strong tendency to conceive of causes as somehow active. And it seems that our difficulty with the Aristotelian causes is due to the fact that they cannot even be conceived of in this way. . . . It is only with Aristotle’s moving cause that we think that we readily understand why it should be called a cause. But it would be a mistake to think that Aristotle with his notion of a moving cause tried to capture our notion of cause or at least a notion we would readily recognize as a notion of cause, though it is significant that people have tended to think that among the Aristotelian causes it is only the moving cause which is a cause really. For Aristotle in more theoretical contexts will tell that it is not the sculptor working on his sculpture who is the moving cause, but the art of sculpture. And with the art of sculpture we have the same problems as with ends, forms, and matter” (125–​26, my emphasis). Cf. Everson 1997, 49ff. and Tuozzo 2011. Similar statements naming crafts as causes are found at Phys. II 3, 195a6; GC I 7, 324b2; and Met. XII 4, 1070b28–​9.

Discreteness in Agent–Patient Relations  169 statement about the efficient cause in the strictest sense, one that makes Aristotle’s conception of causation at least somewhat alien.10 I think this aspect of the statement has often been overstated, especially when it is taken to imply that, in a metaphysically strict sense, the artisan’s knowledge, rather than the artisan, is the intrinsic cause of the product. What, though, is the significance of Aristotle’s telling us to seek the “topmost” cause, on the grounds that “the man builds because he is a builder, and he is a builder in virtue of the craft of building; this, then, is the prior cause, and this way for all things”? The relevant phrase is “he is a builder in virtue of the craft of building” (“ho d’oikodomos kata tên oikodomikên” (195b23–​24). Now, the only reason to think that Aristotle is elevating the builder’s craft-​knowledge as the cause at the expense of the builder is the next phrase: “this, then, [sc. the builder’s craft-​ knowledge] is the prior cause” (195b24–​25). Note, however, that Aristotle does not single it out as being the intrinsic (kath’hauto) cause, but rather only as “prior,” which was earlier distinguished from posterior (i.e., more generic) among what were clearly already assumed to be intrinsic causes. So at most Aristotle is stating that the builder’s craft-​knowledge is somehow basic or more determinate with respect to the causal process, more so than any other entity or feature of the builder one might name. However, this does not imply that the builder is not an intrinsic cause of what he builds, or in any way not an efficient cause “strictly speaking.” Aristotle has already drawn the distinction between intrinsic and co-​incidental causes earlier in the passage, and the builder falls explicitly on the former side. Indeed, in the very next sentence he reverts to naming things like “the statue-​maker” as particular causes of statues, rather than anything like the statue-​making craft.11 Since the rest of the passage is a series of points about the different ways, more and less perspicuous, of citing causes, rather than an inquiry into the precise nature of causal action, we should assume that this injunction is

10 See, e.g., Menn 2002, 96; Leunissen 2010, 17; Tuozzo 2014, 32; Fernandez and Mittelmann 2017, 161f. 11 Nor is there any reason to think that the builder is relegated to being a kind of instrument of the art of building, or that ‘the builder’ refers in fact to the builder’s body, which is (on Aristotle’s view) tool-​like (organikon); Menn 2002, for example, discusses the manner in which the body is organikon, but treats the builder as equivalent to the builder’s body (e.g., 124ff.). Compare also the introduction of the distinction between intrinsic and co-​incidental causes in Phys. II 5: it is the one capable of building, or someone’s being skilled in building (to oikodomikon), not the craft (hê oikodomikê), that is named as the intrinsic cause of the house (196b26). Cf. Mansion 1946, 233.

170  Causality and Causal Explanation in Aristotle primarily in the same spirit.12 Of course, more perspicuous statements are such because they somehow reflect what is really the case, but in this instance there is no need for ‘topmost’ to mean “metaphysically strictly speaking.” A more relevant point would be that, since we are looking for the origin (archê) of a normally complex process, in working our way back to it we should go all the way to the start, to the stable or fixed point from which the change proceeds: the builder as such, that is, the builder insofar as he has a stable knowledge of the craft.13 This requires distinguishing exactly what makes the builder a builder, as distinct not only from co-​incidents (in relation to causing statues) like being human or pale but also from other capacities and actions relevant to the process, such as gathering and organizing the production of the relevant materials. (Not to lose sight of the parallel with generation, Aristotle would want us to distinguish, as he does in the GA, what makes a male parent a potential progenitor from other features more or less distant from that aspect of being a male of the species).14 Similarly, in explaining the causal action of fire on other types of stuff, we work back to the heat which both partially makes fire what it is and accounts for its having the active powers it does. The primary aim of the injunction, then, seems to be to make sure that we carry our inquiry all the way back to the appropriate starting point, not settling for anything intermediate, until we reach the aspect of the substance by which it is a potential agent of a given sort.15 It is not meant to imply that the builder is somehow only loosely speaking the efficient cause of what he builds. The more important metaphysical distinction seems rather to be the distinction between actual and potential causes, which presents other 12 Where Aristotle does aim to be metaphysically precise about generation, in chs. 7–​9 of Met. VII, he is likewise ambivalent between naming craft-​knowledge and the artisan as agents. He says (VII 7, 1032a27–​28) that all actions (poiêseis) are either from craft (technês) or capacity (dunameôs) or thought (dianoias), and that when something like health comes to be by craft, “the agent (to poioun) and that from which the change originates (hothen archetai hê kinêsis)” is “the form in the soul” (1032b22–​23). Less than two pages later, he says that “the begetter (to gennôn) is sufficient to produce (poiêsai), i.e., to be the cause of the form in the matter” (VII 8, 1034a4–​5), and the ultimate lesson in ­chapter 9 is that for a substance to come to be, there must antecedently exist in actuality a substance which acts (heteran ousian . . .hê poiei) (1034b16–​19). 13 He makes a similar point at GC I 7, 324a27–​28: the archê is the first among the causes, which in context is clearly making a point against those who would cite only the proximate cause, e.g., the builder’s tools. 14 Cf. GA I 2 716a27–​31: even though the whole animal is called male or female, they are only such with respect to a certain capacity and a certain part. 15 This also seems to be how Simplicius interprets the injunction (326, 19–​20). It should also be noted that this passage about citing the topmost cause is not in this chapter’s doublet, Met. V 2, nor does Aristotle attempt to apply the distinction to the other causes. So one should be wary of inferring too much on its basis.

Discreteness in Agent–Patient Relations  171 difficulties.16 The difference as applied to the builder seems clear enough: the builder as such is a potential cause, while the building builder is an actual cause.17 On the effect side, the house being constructed is also clearly enough the actual effect, whose existence is co-​eval with the actual cause, though it is less clear what the potential house is—​presumably the matter when it has been organized just up to that point at which the builder’s craft-​knowledge can come into play directly (again following the parallel with animal generation).18 When we try to fit these two distinctions together, however—​the “topmost” cause and the cause as potential or actual—​the result is puzzling. The builder’s craft-​knowledge, as Aristotle is explicitly aware, does not itself change before, during, or after any building activity—​this is why it can be a principle (archê). If so, any reference to it is ambiguous between merely having the craft and using it, and so it is hard to see what metaphysical difference there is between the actual efficient cause and the merely potential one, though Aristotle thinks they are different the way unbuilt materials and materials in process of being turned into a product are different. This is perhaps a better source of the difficulty modern commentators have sometimes seen with Aristotle’s efficient cause: it is not that as described, the efficient cause is not “a thing that does something to something else,” but rather than when it does so, nothing is strictly speaking different about the agent as such as compared to when he is not acting. And if nothing happens in the agent as such, it is hard to see the active efficient cause as effecting anything at all. Nevertheless, Aristotle says that the agent and the active agent have different identity conditions, as we have just seen (195b17–​21), so he clearly thinks that they can be distinguished. On the one hand, then, it is tempting to see active, particular causes as efficient causes most strictly speaking, but this seems to be in tension with the thought that, most precisely speaking, the aspect of an agent which constitutes 16 This distinction, of course, means that with regard to efficient causes Aristotle is in some sense a “powers” theorist. The contemporary literature on causal powers, much of it explicitly Aristotelian or neo-​Aristotelian, is vast, and a number of distinct positions have been articulated. The variety of causal profiles Aristotle recognizes, and the distinction between origin-​dominant and end-​dominant profiles, raise issues analogous to those discussed in recent debates about the natures of properties, powers, and dispositions, though I will not pursue the connections here. For an overview of the modern debates, see the essays in Bird, Ellis, and Sankey 2011. 17 Fine 1987, 71–​72, notes the importance of this distinction; however, she argues that active agents should be considered components of events, which I do not think is correct, for the reasons given in the next section. 18 Alexander apparently found the reference troubling; see Simplicius’s commentary, 326, 41–​ 327, 6.

172  Causality and Causal Explanation in Aristotle the origin of the change remains the same throughout, whether active or potential. The tension seems to be that Aristotle is keen to define and preserve the reality of change but also to ground it ultimately in something fundamentally stable, which is what motivates the injunction to seek the “topmost” cause. However, we should not exaggerate the significance of the fact that the agent qua agent does not change during an interaction. Aristotle’s example of craft is a complex activity with a clear distinction between the ultimate origin (archê) and the proximate efficient causes of the component changes being wrought in the matter, namely the builder’s tool-​like body and its movements using actual tools, as well as the corresponding small changes to the materials by which they come to constitute a complex artifact.19 By contrast, in a simple interaction between basic material compounds, there are no intermediate efficient causes, and it is correspondingly less puzzling to say that under the right conditions, the agent simply acts on the patient without itself changing qua agent (the hot fire melts the cool wax), even if, as a matter of causal necessity, the agent in many cases is also acted upon by the patient.20 This difference seems to be a mark of agency as opposed to patiency: the patient’s capacity to undergo a certain change is typically “used up” in the change, in at least one sense, but the origin of the change—​the agential capacity—​persists through the change. At least in Aristotle’s paradigm cases, once the patient is actually F it can no longer become F (though it still normally has the material basis of being F or not-​F, for example, a surface or a body that can be heated and cooled without being destroyed).21

19 Aristotle clearly distinguishes between complex changes and the more basic kinds of change, such as alterations in qualities like temperature or density, on which such changes depend; see especially Phys. VII 3. 20 For a contrasting interpretation, see Tuozzo 2011, who rightly brings out the stable aspect of agents as such, but argues that this implies that efficient causes in the paradigm sense are unmoved movers; as well as Judson 1994, who distinguishes between “energetic” and “non-​energetic” efficient causes; and Gill 1994, 21–​23, who argues that forms in the soul like craft-​knowledge should be thought of as sets of instructions rather than as origins of causal sequences. On reciprocal causal interactions, see GC I 7, 324a30–​b13, and GA IV 3, 768b15–​25: “The cause of the weakening of the changes is that what acts is also acted upon by its patient (for example what cuts is blunted by what is being cut and what heats is cooled by what is being heated, and in general what brings about change (to kinoun), except for the first mover, undergoes some change in return; for example, what is pushed is pushed back in return, and what compresses something suffers an opposite pressure in return; and sometimes it is thoroughly acted upon rather than acting, i.e. what heats is chilled, what cools is heated, sometimes effecting no action, and sometimes less than it undergoes. These matters have been discussed in the works that examine acting and being acted upon, and in what sorts of things there is action and being acted upon).” 21 This analysis of agency and patiency raises problems of its own, especially since, as we have just seen, Aristotle is aware that in many paradigm cases there is a corresponding and opposed reaction by which the agent is changed, and indeed changed in such a way that at the end of the interaction

Discreteness in Agent–Patient Relations  173 One general claim that Aristotle makes which ought to be separated out from this nest of complications, then, is that agents and patients as such are qualified subjects—​hot dry fire and cool moist clay, for example—​rather than qualities themselves.22 Indeed, the fact that contraries do not act on each other directly is one of the main reasons the concept of matter-​as-​subject is required for an analysis of change in Phys. I—​a further reason to resist the thought that a quality like craft-​knowledge, rather than the expert, is supposed to be the “real” efficient cause. Likewise, in turn, even if every agent in at least a range of interactions also suffers a simultaneous reaction, it is the substance qua capable of being changed that is the direct subject of the reaction, and the subject qua capable of acting that is the agent as such—​and these are distinct from each other as well as the relevant qualities or capacities as such. This view is hardly indefensible, and so if Aristotle’s analyses of basic types of physical change in terms of agents and patients are problematic, I do not think the culprit is his understanding of causality in general or his view that efficient-​causal explanations should seek a stable principle in virtue of which the agent is capable of acting in certain ways. The distinctions of II 3, then, provide tools for giving accurate formulations of causal explanations, so that they can pick out intrinsic efficient causes and effects, and for tracing a causal process back to a stable starting point in the intrinsic efficient cause. To get a better understanding of what Aristotle thinks actually happens in a causal interaction, then, we must turn to the analysis of agent–​patient interaction.

it no longer has an agential capacity; he also thinks that the universe consists in a series of nested spheres in eternal transeunt motion caused by a “Prime Mover.” So the idea that changes should ultimately be explained by reference to a stable origin connects to a series of complicated questions about Aristotle’s views of agency and patiency—​some of which seem to flow from his general views about causality, some of which pertain instead to contingent claims about nature (i.e., the “sub-​ lunary world”), and some of which pertain to cosmological and theological claims. However, since he takes natural science to be occupied entirely or primarily with moved movers (Phys. II 7, 198a27–​31), we should assume that even moved movers have a stable aspect in virtue of which they function as origins of change. We should thus distinguish between the claim that moved movers are metaphysically posterior to unmoved movers, and the claim that they constitute a special case or secondary sense of ‘origin of change’, since it is in the study of nature that the notion of an efficient cause is elaborated. In the absence of any conceptual claim to the contrary, we should take all the examples as on a par in that respect, even if they differ in other respects. See also Gourinat 2013. 22 This point, and the mistakes that arise from treating either the qualities of the subject or the subject itself in isolation, are discussed in GC I 7, especially 323b15–​325a24.

174  Causality and Causal Explanation in Aristotle

8.3.  Transeunt-​Causal Change in Physics III 3 To address this question, it is more helpful to ask, not which entity Aristotle might single out as the true efficient cause, but rather what components and stages he thinks comprise an interaction between an agent and a patient. Aristotle’s view of the “causal nexus” in a transeunt causal interaction comes out in response to the quasi-​Humean challenge in Phys. III 3 already discussed (§ 6.3), which raises worries about the consequences of supposing that in such interactions, there are activities (energeiai) or actualizations (entelecheiai) of both the agent and the patient.23 The answer given is that the agent’s activity is located in the patient, not the agent, and that in fact the agent’s activity and the patient’s undergoing the change are the same, though “different in being (to einai) and account (logos)” (202b5–​16). This qualified sameness must be explained. Aristotle illustrates it with an example: the road up is the same, but not strictly the same, as the road down: And the answer to what was being puzzled over is clear: that change is in what gets changed; for it [sc. change] is the actuality of the latter [sc. what gets changed] by what brings about change. And the activity of the agent of change is not something other [than this]; for it must be the actuality of both. For while it is such as to bring about change by having a capacity, it brings about change by being in activity—​but it is such as to act on what gets changed, so that there is a single activity for both, in just the same way that the same interval spans from one to two and from two to one, and [likewise] the road up and the road down. For these are one, but their accounts are not one; and it is the same way with what brings about change and what gets changed. (202a13–​21)24

Aristotle’s claim here, then, is that there are in a sense only two elements to a singular causal interaction: the agent and the change it effects in the patient, which is both the agent’s actuality qua agent and the patient’s actuality qua patient. Aristotle’s star example of teaching is slightly misleading insofar 23 Aristotle uses both terms in the passage. ‘Entelecheia’ implies completion or perfection (and so is often translated ‘actuality’, ‘actualization’, or even ‘perfection’), whereas ‘energeia’ implies being “at work” (and so is often translated ‘activity’, but ‘actuality’ is also common and sometimes preferable). Much about how to understand these terms is disputed in other contexts, but commentators agree that Aristotle uses them interchangeably in this passage. 24 The example is recapitulated further down in terms of endpoints: the road from Athens to Thebes and the road from Thebes to Athens are “the same” in this special sense (202b13–​14).

Discreteness in Agent–Patient Relations  175 as it may seem evident, upon reflection, that the teaching and learning themselves can be treated roughly like discrete events, such that the first might exist without the second (as we so often complain). Perhaps more favorable examples would be simpler interactions such as pushing, heating, or indeed sculpting, for which it is easier to maintain that there is only one activity—​the change, which is both the patient’s being altered by the agent and the agent’s altering of the patient. Thus, we should not make the mistake of taking the agent’s actuality qua agent to be the efficient cause of the change itself, since that actuality is, surprising as the words themselves may sound, the same thing as the change (though not strictly the same)—​it is an explanandum, not the cause.25 (The words may sound less surprising when we recall that once the change has been completed, and hence no longer “is,” a new substance or property of a substance is present, which is not a part of the change that yields it.26) While in some sense we might say, then, that all or at least most transeunt interactions involve two events, for Aristotle the event preceding the change is not a cause, but rather one in which agent and patient come to satisfy all the antecedent conditions for A’s bringing about a change in P; it is followed by the “event” of the agent’s actually bringing about the change in the patient—​ that is, the change. So by rejecting the thought that there is any activity of the agent as such other than the change brought about in the patient, Aristotle has in effect accepted that some phenomena, including transeunt changes, are essentially causal. Causality in agent–​patient interactions is thus not something that supervenes on intrinsically non-​causal facts, events, or states of affairs.27 As I shall argue in Part III, this has some important consequences for causal epistemology, but here the relevant consequences pertain to the ways in which it may or may not make sense for him to say that the elements of a causal interaction are “discrete.” To understand the causal nexus, then, we need a clearer understanding of this claim of qualified unity, that the agent’s and patient’s actualities are “one, but not one in account.” Aristotle is not entirely precise about it, and 25 Nor again should we make the mistake of thinking all transeunt efficient causes are agents, since agents are only a species of mover: cf. GC I 6, 323a12–​20—​on this account at least, a colliding billiard ball is a mover but not an agent. 26 The distinction is related to later ancient debates about the precise category that ought to count as the “effect,” e.g., “statements” (lekta), predicates (katêgorêmata), or something else, but Aristotle does not argue in these terms (see Gourinat 2013, § 2). 27 As I noted in the Introduction, I take this supervenience thesis to be an assumption governing much of the recent literature on causation.

176  Causality and Causal Explanation in Aristotle commentators tend either to disagree or to give accounts which do not seem to get to the heart of the matter. Moreover, saying that two things are in a way one but in a way not is a rather common move for Aristotle, and we have already seen examples with respect to formal and final causes which show that he may not always make the move in a single precise way. The difficulty for this case turns on whether and how the difference in “account” reflects any sort of internal complexity or division within the change itself. Some commentators, broadly speaking, ascribe the difference to some sort of intensionality or co-​reference. It is clearly insufficient, however, to interpret the point as simply that the change may be described either as acting or being acted-​upon, as Ross (1936) suggests (541)—​the change may be described in all sorts of ways which do not have the relevance of the specifications as action and passion. Others gloss the relationship in terms of different truths about the change corresponding to different “aspects” of it.28 These differences seem to obtain as well, but again not to capture the point. Aspects or aspect-​relative truth, for example, are common phenomena, which do not require any special status or qualified unity when it involves multiple subjects. A certain plant may be both waxy and spiny, but for all that it is one plant of a given kind, and there is no need to say that that its being waxy and spiny are “one but different in account.” Likewise, it may be true of a change that it is rare qua “of the agent,” if the agent is a rare producer of this sort of change, while common qua “of the patient,” if the patient is a regular sufferer of it, but this does not help us understand how a single change may be both “of the agent” and “of the patient,” while at the same time being different “in being.”29 Other commentators interpret the claim as positing metaphysical complexity within a change. This approach, by contrast, risks making action and passion too distinct for Aristotle’s purposes, since if agent and patient each make a separate “contribution” to the change, these would seem to be distinct actualities.30 But, after all, Aristotle is, from the start, aiming to avoid 28 Coope 2005 states that “the action of the agent and the change of the patient are one and the same change, but what is true of this change insofar as it is of the agent is different from what is true of it insofar as it is of the patient” (211), and argues that while the teaching is the same as the learning, the state of the teacher and the state of the learner are different (214–​15), though she also describes them as “aspects” of the change (216). For a similar view, see Waterlow [Broadie] 1988, 200–​201. 29 Gill 1980, 141, also seems to make the relationship a matter of co-​reference. 30 Marmodoro 2007, for example, criticizes “one-​entity-​two-​descriptions” interpretations and argues instead that Aristotle is introducing a new type of “two-​in-​one” entity, which “consists of two natures grounded on an underlying physical activity” (228). This position rightly requires that ‘logos’ be read as referring to essence-​specifying definitions (in agreement with Hussey 1983, 66–​71). Cp. Anagnostopoulos 2017, § 4. More strongly, Charles 1984, 10–​15, argues that teaching and learning

Discreteness in Agent–Patient Relations  177 the problem that arises when we attribute distinct actualities to agent and patient, and he is clear that the solution involves recognizing only one. Aristotle’s position is hard to describe well because, if he is making a point about the structure or nature of changes, it is a philosophically difficult position to clarify. Insofar as he says that the agent’s and patient’s activities are “different in being,” he seems to allow for a real distinction to be drawn between them, and so it is natural for commentators to think of the change as in some sense a composite. On the other hand, once we specify that the agent’s activity as such is in the patient, and that there is only one actuality which is both the agent’s and the patient’s, it is difficult to see how it could be anything other than the change itself—​the actuality of what is in potentiality as such. Aristotle is clear that this actuality, even if incomplete, is a unity in its own right. To be sure, the teacher may speak and gesticulate, the doctor may speak and move her limbs, but these activities are, to use Coope’s language, both of the agents and in them, and so are neither the same as their actualities qua agents, which are of the agents but in the patients, nor are they parts of the change.31 If so, then attempting to somehow decompose a transeunt change into the agent’s contribution and the patient’s contribution would be a mistake. To the extent that there is something composite in such a change, it would rather be the potentiality, whose grounds are distributed among the agent, the patient, and any intermediate or background materials and conditions required for the one to act on (and in) the other. And if the actual change itself is not a composite, it is hard to see how its unity is compromised in any way. We should thus not make the mistake of attempting to treat the active agent and the suffering patient as analogous to the discrete causes and effects which we find in a typical “three-​factor” view of causation as a two-​place relation (Cxy) ranging over events. I think that Aristotle may rather be making a categorial point with this claim about sameness and difference-​in-​being. He is trying to solve a dialectical worry about whether it makes sense to say that a potential agent and a potential patient have the same actuality—​that is, that the actualizations of are in fact numerically distinct processes (kinêseis), which are only one in the sense that the learning underlies the teaching as matter underlies form (15). It is not always clear, though, the extent to which commentators wish to endorse these as analyses; Marmodoro is explicit in her “two-​in-​one” analysis, but, for example, Coope and Charles are more circumspect. 31 See Coope 2005, 212, for this language. Even those who would more sharply distinguish action from passion seem to accept this characterization.

178  Causality and Causal Explanation in Aristotle their capacities are somehow one thing. The consequence to be avoided is that, if only one actuality is present when, for example, A teaches P, somehow either both A and P will turn out to learn, or, more broadly, teaching and learning will turn out to be the same thing (202b1–​5). The key part of the solution comes at the end: “to speak generally, teaching is not the same in the primary sense as learning, nor is acting-​upon the same as being-​acted-​upon, but rather that to which these belong (huparchei) is the same—​the change” (202b19–​21).32 ‘Huparchein’ has several uses in Aristotle, and it can indeed mean something like “be present in,” which would fit with a compositional reading; one of its uses, however, is to indicate predication, and reading it this way here is encouraged by the point about definition that immediately follows.33 A natural way of expanding the initial thought would therefore be that, for transeunt changes, both the active and passive terms (such as ‘teaching’ and ‘learning’) are correct answers to the essence-​seeking question, “What is it?”: predicates in both the categories of action and passion are, properly speaking, “said of ” the change, and indeed, as I have argued earlier (§ 6.3), a scientific statement of its real definition will refer to both agent and patient as such. The point is an important one for Aristotle especially, insofar as he typically recognizes acting (poiêsis) and being acted-​upon (pathêsis) as distinct categories.34 One can imagine an objector, indeed, claiming that Aristotle himself is subject to the puzzles raised at the beginning of Phys. ΙΙI 3, since he holds that building and being-​built are strictly speaking items in different categories, and which naturally would be thought to inhere in distinct subjects. If something is an instance of pushing, the objector points out, it is not also an instance of being-​pushed, and anything that is pushing something is not also being pushed, except co-​incidentally.35 His proposal here would respond to the worry by pointing out that one and the same change might be the actuality of more than one potentiality, and be the proper subject of

32 ‘Teaching’ and ‘learning’ translate the nouns ‘hê didaxis’ and ‘hê mathêsis’ respectively, which Aristotle treats as different from the articular infinitives ‘to didaskein’ and ‘to manthanein’; commentators disagree as to the precise sense of the infinitives. Coope 2005, 212, argues, controversially, that they refer to the states of being a teacher and a learner respectively, rather than the essences of being a teacher and a learner. The nouns, though, clearly refer to the action and passion, the precise nature of which is what is under examination. 33 Also noted in this context by Hussey 1983, 71. 34 As at Cat. 1b27 and Top. I 9, 103b23. 35 That is, they would appear to be neither “said-​of ” nor “in” the same subjects. See Cat. 2, 1a20–​1b9.

Discreteness in Agent–Patient Relations  179 items in different categories, without absurd consequences.36 One might then worry whether changes can be subjects of predication, but Aristotle could respond that since such changes are “incomplete actualities,” it does not follow that they are improper subjects of predication, especially “said-​of ” predications: just as we can classify different kinds of motion as circular, rectilinear, and so on, so we can apply different transeunt-​causal predicates to changes or changing subjects.37 This reading would fit with the overall likelihood that Aristotle is raising a dialectical (“logikôs”) worry which is solved by examining the phenomenon in the way characteristic of natural science (phusikôs), especially by recognizing the distinction between actuality and potentiality. Indeed, the point is strengthened if my interpretation of the “more intelligible” way of defining such changes is correct.38 On that reading, these changes, considered on the pre-​theoretical (Phys. V) account of change, admit of two types of predicates (one agent-​focused, one patient-​focused), which have distinct pre-​theoretical definitions, but, as it turns out, a single theoretical definition that captures both the agent’s and the patient’s capacities (on the Phys. III account of change). What has happened, however, to the “active particular” cause from Phys. II 3—​the building builder? Aristotle says there that “the things that are in activity and particular are and are not at the same time as those things of which they are causes” (195b16–​20); that is, they are co-​eval, which certainly looks like it recognizes two distinct things, the active agent and the suffering patient. Further, it seems important for him to recognize an efficient cause which is both a necessary feature of every causal interaction and yet does not precede or outlast the change. This is because, as we have seen, one of his objections to Plato was that Forms simply are what they are all the time, but then, if they are also supposed to be efficient causes, they would constantly be producing things and bringing about changes, but they do not. And yet

36 Perhaps this is why he sometimes collapses them into one category, change, as at Met. VII 4, 1029b24–​25. Cf. Plato, Theaetetus 156a5–​7. 37 For changes described as incomplete activities or actualities, see Phys. III 2, 201b32; Phys. VIII 5, 257b8; DA II 5, 417a16. Aristotle’s view thus resembles in some respects the one sketched by Anscombe 1971, who argues that ‘cause’ is a kind of generic term which is secondary to verbs indicating intrinsically causal concepts, such as “scrape, push, wet, carry” and others (9). Aristotle’s list of basic changes will indeed look a little like Anscombe’s, but we should note that he does not aim to individuate concepts in the way Anscombe seems to, but rather to define types of change in terms of the particular dispositional properties of the agent and patient, as we have seen. I discuss further similarities and differences with her view in Part III. 38 See. § 6.3.

180  Causality and Causal Explanation in Aristotle Aristotle’s view, as I have presented it, would also seem to prevent him from recognizing a further distinct entity or “actuality,” the acting agent, since the thought that the agent might have its own actuality distinct from that of the patient is precisely what gives rise to the challenge in Phys. III 3. Now, the claim about temporal co-​extension in Phys. II 3 comes at the end of the list summing up the various ways of speaking about causes, including in combination, so Aristotle may simply be speaking in the formal mode, without attending to the ontological nature of changes. In this case, if pressed, he might say that the descriptions do after all refer to the same thing, which is why their referents are temporally co-​extensive. Alternatively or in addition, since he is talking about complex actions which in many respects and contexts can be treated as activities of the agent, he can distinguish the various components of the builder’s action (decision, planning, as well as bodily motions and uses of tools and so on, analogous to the movements of the seed in generation) which comprise the transeunt action of building.39 It is only when considered as a whole action of building, for example, in deploying one’s craft-​knowledge on suitable materials, or when the interaction is simple, that there is no distinct activity on the side of the agent. Either way, the action does not consist in a change in the agent, even if, as a matter of the way nature works, a certain kind of agent is also reciprocally changed when it acts on a given kind of patient. Just as, he thinks, when we think about something that we know, we are not changed—​that is, we do not (necessarily) undergo any qualitative, quantitative, or spatial change that precisely constitutes our thinking about it—​so, too, when an agent acts, it is not changed with respect to whatever it is that makes it capable of acting, but rather, simply, acts.40 So the claim in Phys. II 3 about the active agent would then appear to be a local one, focused on the ways of specifying intrinsic causes as such, but the claim about agent and patient in Phys. III 3 is not merely a local one; Aristotle also affirms it clearly in Met. IX 8, 1050a30–​b1. Thus, transeunt changes are not in need of decomposition or division into quasi-​ parts or aspects corresponding to the agent’s and the 39 Aristotle seems in fact to treat building as an activity (energeia) in some places, notably Met. IX 6, 1048a37–​b4. That he seems to is one of the many difficulties commentators have faced in understanding his claims about the contrast between activity and change; see p. 142 n. 25 earlier. 40 By contrast, on Aristotle’s view, for an intermediate mover B in a chain of movers, it is precisely because it is being moved by something else that B in turn moves the next in the sequence. The details of Aristotle’s views about moved and unmoved movers are highly controversial, especially as they relate both to his views about divine natures and his views about psychological phenomena (where they connect once again with questions about activity and change). Nevertheless, I do not think these issues are at play in Phys. II 3’s discussion of actual and potential causes.

Discreteness in Agent–Patient Relations  181 patient’s contributions; they are unified actualities whose grounds—​that is, potentialities—​with respect to agent and patient are ontologically distinct. It is instead a basic fact about natural things that the actualities of some agents are in other things as subjects. There is no further nexus, no “cement,” no further production relation that constitutes the efficient cause bringing about its effect. There is the agent, the patient, and in the right circumstances, the change that the agent brings about in the patient. If we find this puzzling, it perhaps has more to do with the fact that we expect a causal analysis, rightly or wrongly, to have three components corresponding to two distinct relata and a relation between them. As noted earlier, most modern accounts frame their analysis in such terms, along with some sort of supervenience thesis, to the effect that causal relations should be analyzed—​reductively or not—​in terms of relations between non-​causal states of affairs, which are taken to be ontologically more basic than causal ones. If I am correct, Aristotle rejects this for philosophical reasons that run rather deep: he thinks that many basic phenomena, such as regular changes and generated beings, are essentially causal kinds, and even if they are ultimately causally related to something even more basic than they are, this is not because their causal nature must be grounded in something which is intrinsically non-​causal.

8.4.  Varieties of Discreteness The net result of II 3 and III 3’s discussions of transeunt efficient causation, then, is that accurately described, efficient-​causal origins (archai) are stable features of agents and movers, which yield transeunt changes in suitable patients under suitable conditions. These transeunt changes fall under kind terms of two sorts, agent-​focused and patient-​focused, but their real definitions include both the efficient and the material cause, as we have seen. This means that the question of discreteness should not be applied to cause-​ events and effect-​events, one taking place in the agent and one in the patient, but rather to the relation between agents and the changes in patients they produce. How, then, does this view fare with respect to discreteness? The philosophical trouble with discreteness is broadly that, as Hume and others have noted, if causes are genuinely, fully distinct from what they cause, and vice versa, then it is difficult to see how there can be any strong sense in which the effect depends on the cause, at least not one which yields an intelligible link between two realities. Aristotle’s own worries about

182  Causality and Causal Explanation in Aristotle reductionist views express one version of this worry. If the atomists or reductionist pluralists are right about causal principles, he thinks, then their relationship to any given natural phenomenon other than their own essential activity turns out to be co-​incidental, which means, he thinks, that the phenomenon into which we are inquiring is not really a suitable object of scientific inquiry after all. (We might say these phenomena depend on their material components in one sense, but really there is no robust phenomenon to account for at all). Likewise, of course, for separate Forms. On the other hand, as noted earlier, without discreteness we seem to lose any sense that one thing is explaining something else, and so it is difficult to see what explanatory power remains. Though there are a variety of worries about discreteness one might raise, these worries about explanatory power are sufficiently broad to capture what I take to be its primary philosophical importance. (They also, I think, fit reasonably well with the spirit of Hume’s critique, with its focus on inference, and the philosophical context of the rationalist tradition against which he is primarily arguing, including especially the thought that a complete account of a cause logically entails the effect.) However, there are several ways in which one might claim that two things are discrete, which in turn have different implications for questions about explanatory value. Indeed, it has turned out to be extremely difficult to state “Hume’s dictum” that there are no necessary connections between distinct existences (or implications about existence) in a way which is both non-​ trivial and does not beg the question against someone who might wish to defend some form of causal realism.41 Obviously, for example, the straightforward gloss of discreteness for X and Y as “X is able to exist without Y and vice versa” is either question-​begging or too coarse-​grained to work against a realist view about causation. Ultimately, I think, the most fruitful approach is not whether there is a single account of discreteness which best captures the Humean worry, and what Aristotle would say in reply, but rather to understand which notions of discreteness do and do not apply, and how, to the main components of causal interactions. The following five notions of discreteness

41 Canonically, Treatise Book I.III.XIV, and Enquiry, §§ 4 and 7, e.g.: “The mind can never possibly find the effect in the supposed cause, by the most accurate scrutiny and examination. For the effect is totally different from the cause, and consequently can never be discovered in it” (Enquiry 18). For a careful recent study of the claim and its prospects in the context of contemporary metaphysics, see deRosset 2009.

Discreteness in Agent–Patient Relations  183 are all worth distinguishing, and all capture different aspects one might wish to understand about how causes and their effects relate.42 The first basic idea is to gloss discreteness in terms of a modal notion of existential independence—​two things are discrete if they can exist independently of one another. There are stronger and weaker versions of this kind of independence, however.43 (1) “Thin” (one-​way) existential independence: X and Y are existentially discrete in the thin sense just in case either X can exist without Y or Y can exist without X. This criterion is difficult to specify without question-​begging in the context of causation, which is perhaps why the debate was sometimes framed in the early modern period in terms of whether God could create the effect without the cause. More recently the criterion has been framed in terms of whether one or the other could inhabit a “lonely universe.” (2) “Thick” (two-​way) existential discreteness: X and Y are existentially discrete in the thick sense just in case X can exist without Y and Y can exist without X. As usual with such modal notions, we need to be careful in specifying the type of possibility involved: a skeptic about causal relations could well accept that given the laws of nature, when something of type C comes about, something of type E (naturally) necessarily comes about, while a realist could well accept that there are logically possible worlds in which something of type C comes about, and nothing of type E comes about. Because of the difficulties involved in using modal notions to explicate or critique views about causal relations, there are also non-​modal relationships pertinent to glossing discreteness: (3) Mereological discreteness: In some ways the simplest version of discreteness we might hope for uses criteria for distinguishing different objects. Thus, we might think two entities are discrete just in case

42 The list is partially drawn from Stoljar 2007 and Wilson 2010, who develop them precisely in relation to “Hume’s dictum.” I am ignoring numerical distinctness, which they both include, since in this context, and especially given Aristotle’s own distinctions regarding sameness and unity, the notion seems only to raise the same questions rather than settle them. 43 This distinction corresponds roughly to Stoljar’s distinction between weak and strong modal distinctness.

184  Causality and Causal Explanation in Aristotle neither is a (physical) part of the other, nor do they have any spatial parts in common. Mereological criteria do capture some ways in which causes are supposed to differ from their effects: setting aside the fact that material composition is a causal relation for Aristotle, many part–​whole relationships are incompatible with causal relationships, especially efficient causal ones, which are at issue here—​he does not think, for example, that the first minute of a motion causes the second minute, or that the motions of my fingers efficiently cause the motion of my hand.44 However, mereological relationships also face various difficulties in capturing some of the ways causes and effects are supposed to be discrete. Not all purported causes and effects are easily construed as objects, and sometimes a part of X does seem to bring about an effect in the whole, as when my body’s immune system causes my body’s temperature to rise. (4) Discreteness of intrinsic features or properties: A further non-​modal account, then, states that two entities are discrete just in case they do not share any intrinsic features, or their intrinsic features can all be specified without reference to each other. In this literature, of course, ‘intrinsic’ is not being used as a placeholder translation of ‘kath’hauto’, and we face some well-​known challenges in specifying what counts as intrinsic in the contemporary sense. In this context, at least, it seems artificial or question-​begging to separate a thing’s existing and having certain properties from the direct consequences of its existing and having them. Thus, for a thing with a certain surface structure that will be perceived as red by certain subjects, it seems reasonable to take the surface structure to be intrinsic, and the tendency to be perceived as red to be extrinsic, but unreasonable to take these as being wholly discrete or “distinct existences.” The Humean, at least, need not claim that something’s having that structure lacks any implications for its perceptible qualities (its being actually perceived by a given subject is another matter, of course), nor does the causal realist wish to take the way surface structure is responsible for something’s perceptible qualities to be the paradigm for causal explanation in general. So we might include in the notion of intrinsic properties the direct

44 Cf. Phys. V 1, 223a23–​28.

Discreteness in Agent–Patient Relations  185 consequences of a thing’s existing and having whatever properties it does, which does not require us to try, artificially perhaps, to separate a thing’s intrinsic properties from what they entail.45 Thus on this account, X and Y are discrete just in case none of X’s properties and their direct consequences are a property of Y, and vice versa.46 So we have, at least for a start, two modal and two non-​modal ways of attempting to specify what makes two particular entities discrete. Another important type of discreteness for our purposes is not directly related to the idea of specifying the identity and distinctness of particulars in the way we distinguish individual objects. Rather, it focuses on the essences or natures of two entities and asks whether either of their definitions makes reference to one another. Thus: (5) Essential discreteness: On this account, X and Y are discrete just in case the specifications of their essences do not overlap: i.e., they make no reference to one another or to one another’s essential properties. This type of independence is non-​symmetrical: it may be that X is essentially independent of Y while Y is dependent on X, either existentially or essentially, or both. (Thus, oxygen can exist and be specified without reference to water, but not vice versa, and Aristotle’s well-​known cases of co-​ordinated homonyms exhibit similar asymmetries.)47 We therefore have five glosses of the notion of discreteness which are pertinent to the question whether and how a cause and its effect are sufficiently distinct that the former might genuinely have explanatory value: two modal criteria (thin and thick existential independence), two non-​modal criteria (mereological and intrinsic property discreteness), and one essentialist criterion. All of these, I think, are reasonable ways of glossing discreteness for our purposes: if the general worry is that explanatory power requires discreteness, then it does seem that failure to be discrete in any of these ways can at 45 This notion of directness is left vague here, since there are a variety of types of plausible “direct” consequences of having properties, including extrinsic or relational properties, but some of these will also naturally re-​introduce modal considerations. 46 See Wilson 2010, 2.2. 47 Stoljar 2007 includes a kind of essential discreteness, but he glosses this as not having any essential properties in common. This would, I think, count correlatives like parent/​child as distinct existences, whereas I think it is important to acknowledge a kind of connection that follows not from sharing essential properties but rather from being either defined in terms of one another or in terms of some other common thing.

186  Causality and Causal Explanation in Aristotle least in some context raise worries about explanatory power. Thus, it is fair to ask whether X can truly explain Y if Y is a part or property of X, if Y is in the essence of X, or if neither can exist without the other. On the other hand, insofar as explanatory power also requires a non-​accidental connection between cause and effect, each of these can also, in some contexts, raise worries on that score as well. Certainly, if two things are discrete in all of these ways, it is difficult to see how they can be non-​accidentally related.48 As suggested earlier, I do not think the problem for the causal realist is so much a question of having some response to a “distinct existences” argument as it is the requirement to negotiate these different tensions in a satisfying and plausible way. As I shall argue, while these notions of discreteness, of course, do not reflect Aristotle’s terminology, they do end up capturing his view rather well, insofar as they allow us to draw distinctions where he does.

8.5.  Discreteness Applied Though I have followed Aristotle’s tendency to illustrate causal interactions in terms of both basic (i.e., immediate) and complex (mediated) kinds like building and generation, this question should be addressed by focusing more narrowly on basic kinds, such as the “chemical” interactions of the Meteorology, since these only involve subjects and their capacities—​there are no further complications resulting from the fact that in changes like reproduction, there is a difference between the origin (archê) and the means by which the agent brings about the change. So we can take examples such as the hardening of cool, moist clay by the action of the dry heat of a fire as our paradigms. As I have suggested, given these distinctions and Aristotle’s analysis of basic transeunt interactions, we should expect a range of answers to questions about how efficient causes relate to their effects. Since these transeunt changes are analyzed as actualities of the agent and patient as such, to a great degree this range of answers is governed by the distinction between actuality and potentiality. 48 There are also more pointed worries for each: normally the existence of the effect is at least in some way sufficient for the existence of the cause, and there is an intuitive pull to the converse; similarly, the idea that cause and effect should have some kind of physical connection rather than just exist at an arbitrarily small spatio-​temporal distance has a certain appeal; and finally, the intuitive plausibility of the PCS rests in part on the thought that a genuine cause must somehow be essentially related to what it causes.

Discreteness in Agent–Patient Relations  187 Starting with the non-​modal types of discreteness: the causal origin of the change—​that is, the features that make something a potential agent—​is mereologically and spatially discrete from both the features that make something a potential patient and from the change itself, though this may require some fine cutting in cases of self-​qua-​other action, such as doctors curing themselves. Insofar as the agent’s and patient’s features as such jointly constitute a single potentiality for the agent to bring about a change in the patient, they are not mereologically discrete from that shared potentiality, but rather jointly constitute it. The agent-​qua-​active and the change itself are co-​ eval, but not in a way which results in any sharing of physical parts, so they are mereologically discrete as well. By contrast, broadly speaking, the active agent and the change are not discrete with respect to intrinsic properties, if the change is intrinsically the actuality of the agent and patient. The existential-​modal criteria also apply differently depending on whether we apply them to potential or to actual causes and effects. Potential causes can, of course, exist without actual effects, as long as the conditions of action remain unfulfilled: they exhibit one-​way existential discreteness. The capacities of any individual of a given agent–​patient pair can exist without each other (two-​way discreteness), though perhaps nothing can have either potentiality unless there is something or other with the corresponding one, at least in principle—​if there is currently nothing moist and cool, at least, then nothing currently has the capacity to harden moist and cool clay by means of dry heat. The relevant degree of temperature and moisture will in these cases not amount to having a capacity to act, for lack of a corresponding patient.49 We can mark this distinction between having the features that ground a capacity and their constituting a capacity by saying that agential and passive capacities are thickly existentially discrete (sense 2) but not discrete with respect to their intrinsic features (sense 4). This is therefore similar to the way having a certain surface structure is existentially independent of a certain type of perceiver’s dispositions to perceive it as red, but not independent with respect to intrinsic features, since it is a direct consequence of each thing’s having the properties it does that they are capable of interacting in the ways they do. This also allows us to be more precise about the difference between the kind of independently specifiable efficient causes in origin-​dominant 49 And, as we have seen, what capacities are constituted by those properties will vary by context and in relation to different sorts of subject. The same degree of heat/​moisture will cause one patient to dry out and warm up, and another to become moister and cooler, and may even be a passive capacity relative to a different range of things. So they are existentially discrete in that sense as well.

188  Causality and Causal Explanation in Aristotle profiles and those in end-​dominant causes, which cannot be specified independently of their effects. Unlike, say, a degree of heat, end-​dominant efficient causal powers, such as the power to generate another organism of one’s kind or the power to teach calculus, are arguably not even existentially independent from suitable patients: except for borderline cases such as cross-​breeding, there is no agential potentiality that such properties will ground that justifies treating them as a unity, without the relevant passive potentialities. By contrast, an actualized agential capacity cannot exist without the corresponding capacity for change being actual as well. This sort of view can look controversial (it seems possible for a teacher to be teaching while a student remains ignorant), but, again, it is important to bear in mind the difference between immediate and mediated agential capacities: the intermediate actions that comprise the teacher’s work are not the same as the actuality of the teaching capacity itself. When we focus on immediate relationships, as in basic interactions, it seems less controversial to claim that the hot thing’s capacity to heat cannot be actualized while the cool thing fails to become hot. In terms of essential discreteness, if we assume that the fundamental properties of the basic elements are independently specifiable, then in at least one way the essential features that constitute the grounds of the agent’s and patient’s capacities are discrete. But since the actual change is the activity of both, and, I have argued, essentially so, it cannot be specified as what it is—​it cannot be given a theoretical definition—​without reference to both agent and patient. Once again, this allows us to mark a clear contrast between causes in origin-​dominant and end-​dominant causal profiles. As we have seen, in origin-​dominant profiles the properties that ground an agent’s capacity tend to be specifiable independently of the result, since they have a natural unity of their own. In contrast, the feature that constitutes being a potential builder or teacher is not capable of being defined independently of the change it brings about, since it is a teleological unity (and normally itself the result of a teleological process of coming to have the capacity to begin with). With respect to these core cases of agent–​ patient interaction, then, Aristotle thinks that efficient-​causal origins are mereologically discrete (sense 3) and, as potentialities, thickly existentially discrete (sense 2) as well from the changes they produce, although in a different sense agential and passive capacities are not discrete from one another with respect to their intrinsic properties (sense 4). Further, when actualized, they are neither

Discreteness in Agent–Patient Relations  189 discrete with respect to intrinsic features (sense 4) nor existentially discrete in even the thin sense (sense 1). These notions of discreteness are subject to further complexity in light of the distinction between pre-​theoretical and theoretical definitions of changes. The change of becoming flushed, considered pre-​theoretically, may be apparently discrete (existentially or essentially) from its cause: coming to have a reddened face is compatible with a variety of causes such as anger, fever, embarrassment, spicy food, and so on, and each of the latter may obtain without someone’s being flushed. But if a given change is a reddening of one’s face due to anger, it is, Aristotle thinks, a different sort of change which happens to look to pre-​theoretical observation just like these others. Considered scientifically, then, in light of its real definition, the change is therefore not essentially discrete from its cause, nor, perhaps, existentially discrete, if cases where anger does not give rise to a reddened face involve either some impediment or unfulfilled condition. The complex range of differences in relationship between different types of efficient-​causal power and the changes in which they result points to a broader implication concerning Aristotle’s metaphysical causal pluralism. The extent to which a cause is essentially indissociable from its effect appears to be a function of the degree to which it approximates or is related to paradigmatic substances and the actualities that are most closely connected with them, that is, to those things that come as close as possible within the natural world to being independent, self-​perpetuating entities, which are what they are “by virtue of themselves.” Living beings and the transmissible, teachable kinds of knowledge characteristic of rational beings, at one end, and perhaps the elemental qualities, at the other end and in a slightly different way, come closest to this kind of independence. In between are a host of complex interactions and actualities which are intermediate both in terms of their degree of ontological uniformity and independence. There is thus a kind of coherence to this plurality of metaphysical relationships, but on the whole this is because Aristotle thinks that the natural world is coherent, not because he thinks that, a priori, causes must relate to their effects in all of these ways. To round out the comparison to what I have called “three-​factor” views of causal interaction, we may note that the change just prior to the transeunt action will also be mereologically (sense 3) and essentially (sense 5) discrete from the action. However, since Aristotle thinks that a given capacity cannot fail to act if the relevant antecedent conditions are all satisfied—​if the first change happens, then the second must as well, as long as nothing

190  Causality and Causal Explanation in Aristotle impedes—​the prior event and the change are not existentially discrete in either sense.50 Nevertheless, the prior change is not itself a cause, Aristotle thinks, but rather the satisfaction of the antecedent conditions that enable the agent to actualize its agential capacity.

8.6.  Aristotle and Modern “Neo-​mechanism” At this point I think we are in a position to begin answering one of my initial questions, namely what it would look like to develop an Aristotelian theory of causation and causal explanation, or for a theory to be a modern cousin of his, the way Lewis’s is a descendant of Hume’s, and Armstrong’s is a cousin of Plato’s. Organizing a theory of causal explanation around the idea of intrinsic (kath’hauto) causal profiles, which capture the structure of the real definitions of certain types of especially constant and repeatable kinds, is in fact a fair way of characterizing the recent set of views known under the heading of “neo-​mechanism.” (Neo-​mechanism is importantly different from the more familiar views that go by the name of ‘mechanism’, in particular the traditional kind of reductive approach that would quite clearly be anti-​Aristotelian through and through.) Here is how the core notion of a mechanism in the “new” sense is described in one of the canonical presentations by Machamer, Darden, and Craver 2000 (MDC): Mechanisms are entities and activities organized such that they are productive of regular changes from start or set-​up to finish or termination conditions. . . . Mechanisms are composed of both entities (with their properties) and activities. Activities are the producers of change. Entities are the things that engage in activities. Activities usually require that entities have specific types of properties. . . . The organization of these entities and activities determines the ways in which they produce the phenomenon. Entities often must be appropriately located, structured, and oriented, and the activities in which they engage must have a temporal order, rate, and duration. . . . Mechanisms are regular in that they work always or for the most part in the same way under the same conditions. The regularity is exhibited

50 These relationships are more or less the topic of my 2012.

Discreteness in Agent–Patient Relations  191 in the typical way that the mechanism runs from beginning to end; what makes it regular is the productive continuity between stages. (3) A description of a mechanism describes the relevant entities, properties, and activities that link them together, showing how the actions at one stage affect and effect those at successive stages. In a complete description of mechanism, there are no gaps that leave specific steps unintelligible; the process as a whole is rendered intelligible in terms of entities and activities that are acceptable to a field at a time. (12)

This canonical account has several strikingly Aristotelian features, including the insistence on the particular features of things and the contexts in which things behave, the distinction between activities as producers of change and the properties in virtue of which entities engage in them, the “always or for the most part” type of regularity they exemplify, and the attention to the idea that causal phenomena exhibit a sequence that typically runs from beginning to end in a certain way (echoing Aristotle’s NRC principle). This resemblance has not been detailed either by the neo-​mechanists or by commentators on Aristotle.51 Although they constitute a family of views within which we find much variation, the core from which they start is broadly accepted and bears a strong affinity to the account of Aristotelian causal explanation I have described here. We should perhaps not be surprised at this affinity, since, even if the neo-​mechanists do not, as far as I can see, cite Aristotle as an influence, they share two important motivations with him: one is to avoid reductionism, including the idea that there is a privileged “level” of explanation, and the other is to find an account of causal explanation which does justice to the kinds of compelling explanation we seem to be able find by detailed examination of complex processes in nature, especially biological ones. Here, for example, is a neo-​mechanist argument from MDC against deductive models of explanation which take “lower-​level” laws to be privileged, claiming instead that in order to render a mechanism intelligible one must appeal to entities and activities at various levels:

51 The latter lacuna exists in part because questions about “mechanism” in ancient philosophy are largely restricted to the narrow conception of mechanistic explanation as a kind of reductive physicalist explanation, which Aristotle, of course, rejects as a complete account. See, e.g., Berryman 2009. The connection is noted by Lennox 2021, 301.

192  Causality and Causal Explanation in Aristotle Deductive models have also been taken to provide an analysis of explanation, with lower levels explaining higher levels through the identification of terms and the derivation of the higher-​level laws from the lower-​level (for the details, see Schaffner 1993). Aside from the fact that identification and derivation are peripheral to the examples we have discussed (as Schaffner admits), this model cannot accommodate the prevalent multi-​level character of explanations in our sciences. In these cases, entities and activities at multiple levels are required to make the explanation intelligible. The entities and activities in the mechanism must be understood in their important, vital, or otherwise significant context, and this requires an understanding of the working of the mechanism at multiple levels. The activity of the Na+​channel cannot be properly understood in isolation from its role in the generation of action potentials, the release of neurotransmitters, and the transmission of signals from neuron to neuron. Higher-​level entities and activities are thus essential to the intelligibility of those at lower levels, just as much as those at lower levels are essential for understanding those at higher levels. It is the integration of different levels into productive relations that renders the phenomenon intelligible and thereby explains it. (23)52

Thus, just as Aristotle thinks that in order to understand reproduction we not only need to understand basic “chemical” interactions, but also appreciate how they are marshalled, integrated, and influence one another in a complex process initiated by the male parent on the worked-​up material provided by the mother and running through a sequence of formations of individual organs, no part of which can be understood without attention to the specific conditions of its realization, so the mechanists claim that there can be no simple “bottom-​up” strategy for explaining all complex phenomena of a similar sort, and that we must explain the actions of various components of a mechanism in their actual causal contexts. There is nonetheless an apparent difference in the way Aristotle and modern mechanists think about their mechanisms: if the MDC presentation is representative, the thought is that the entities and activities that constitute mechanisms produce or explain change, whereas the mechanisms they describe look rather like what Aristotle would consider to be changes themselves: regularly recurring “transitions” in which some suitable subject comes 52 The notion of multi-​level explanation is one important pole of discussion and debate; see Povich and Craver 2018 for an opinionated overview. This commitment, which Aristotle shares, also makes for a point of contact with some difference-​making accounts of explanation, such as Strevens 2011.

Discreteness in Agent–Patient Relations  193 to be or comes to be [F]‌. MDC mechanisms, then, look to be explanantia or causes, whereas Aristotelian “mechanisms” are explananda or effects. Is this a real difference, and if so, is it an important one? I think that a full answer depends in turn on our answers to the epistemological questions, to which I will turn in Part III, but there is enough variety within the family of neo-​ mechanist views to make it clear that this would be a difference of detail, not general approach.53 We may also note that Aristotle and the neo-​mechanists are subject to a similar reply or objection, namely that even if their view captures the right approach to causal explanation for systems of sufficient complexity, it may not be appropriate for understanding ultimate or physically basic phenomena. At the very least, historically, the specific aspects of various kinds of entities and the capacities they have at higher levels of complexity are precisely what we are supposed to ignore when we attempt to render basic laws that apply to all matter as such. Nothing in the neo-​mechanist approach is meant to deny this—​fundamental laws of matter are assumed to involve either non-​mechanistic causality or no causality at all. This limitation on approaches to causal explanation, however, is not peculiar to neo-​mechanist views either: other philosophers have suggested that causal explanation might not be appropriate for describing basic laws of nature, or at least that it is an open question whether there are any basic laws that are causal.54 Once again, I would suggest that if Aristotle’s view as I have reconstructed it is subject to these sorts of objections, then it is at least a sign that I have delineated a theory that is robust enough to be developed and criticized on philosophical grounds.

8.7.  Summary, Comparisons, and Open Questions In Part II, I have presented the philosophical challenge of giving a realist account of causation in terms of tensions that arise from the basic idea that the causes we cite should have explanatory power. In one direction this demand seems to imply discreteness, which in turn implies a contingent connection, 53 Contrast the ambiguity in Andersen 2014a, 275: “Explanations are of regularly recurring phenomena in the physical world that are the end product of, or are constituted by, the operation of such mechanisms; such regularities are to be explained by providing details about the mechanism(s) responsible for producing them” (my emphasis). 54 E.g., Maudlin 2004.

194  Causality and Causal Explanation in Aristotle while in another direction explanatory power seems to require a non-​ accidental, hence non-​contingent connection. I have argued that Aristotle’s view involves applying essentialist strategies to a select array of kinds of transformation, being, and activity, namely those with intrinsic (kath’hauto) causes. Instead of directly relating all causal phenomena to ontologically basic or otherwise metaphysically privileged entities, Aristotle follows a pluralist approach, which recognizes a variety of causal profiles, and looks for intrinsic causes that can figure in the kind of causal definition he thinks applies to these kinds as such. Not all causes are intrinsic causes, however, nor do all phenomena have all of their causes intrinsically. Among the various kinds of causal profile that constitute the essences of natural kinds, the distinction between origin-​dominant and end-​ dominant profiles is of special importance. Aristotle’s basic strategy in dealing with questions we would classify as pertaining to the “metaphysics of causation,” then, is a kind of “bottom-​up” essentialism recognizable from some of his biological treatises, with their focus on the importance of the more determinate kinds and species, but applied more broadly, and not always with teleological causes in a central position. Thus, to see the natural world as an Aristotelian natural scientist is to divide it up into the things, including changes, that have an internal causal unity to them, such that they are what and how they are both in virtue of themselves, and in virtue of the intrinsic connections some of them have to each other, as distinct from the things to which they are co-​incidentally related. His position is neither anti-​metaphysical nor skeptical, but nor does he give a single account of the metaphysics for any particular mode of causality. Because of his metaphysical pluralism, the precise relationship between any type of cause and what it causes will vary depending on the causal profile in question, as will the precise ways in which they can satisfy these properties of discreteness, non-​accidentality, and contingency. With respect to the key case of origin-​dominant transeunt-​causal interactions, efficient causes are discrete from their effects in some senses but not in others, and in some ways as potential but not as actual. Broadly, potential efficient causes are discrete from their effects in important respects in which actual efficient causes are not (mereologically and thick-​existentially); similarly, the changes which constitute the actuality of the potential agent and patient are mereologically and essentially discrete from the event immediately preceding the change (what a typical three-​factor view might identify as a cause), but not existentially discrete from it.

Discreteness in Agent–Patient Relations  195 This kind of answer has the Aristotelian “in a way yes and in a way no” structure, which is typical of his responses to questions that involve using terms like ‘discrete’ in an unreflective way. It also exemplifies his methodological approach of privileging determinate species in nature over general accounts, which often turn out, he thinks, to apply across kinds only in an analogical way. His approach, as I have reconstructed it, also aims at resolving the tension among discreteness, non-​accidentality, and contingency without separating the grounds of non-​accidentality from the entities involved—​in contrast to Plato, Hume, and Kant, who, in their different ways, do. So, just as Aristotle gives an account of causality without a special ontology, so he also does not make use of a notion of laws of nature. It would, indeed, be inaccurate in several ways to try to reframe this view using quasi-​ Newtonian laws of the sort that state “given a subject S in state A at t1, necessarily S is in B at t2,” in part because for Aristotle such momentary states are dimensionless abstractions (the way points on a line and “nows” in a period of time are abstractions55), and in part because he considers the temporal antecedents up to the initiation of a causal process of change to be antecedent conditions, not causes. Nor is the relation between an efficient cause and what it brings about of uniform type with respect to contemporary distinctions between difference-​ making and productive efficient causes. This is not just because a mover bears different relations to the results of changes and generations. Sometimes an agential power triggers a simple change; sometimes it governs a complex process involving feedback loops (as in the migratory bird example); sometimes a cause like desire sustains an activity, or a property initiates a subsequently self-​directed process; sometimes an agent merely removes an obstacle to something’s exhibiting its natural tendencies. We might wish to count these all as “production,” but Aristotle thinks they divide into kinds with causal essences, and any more general statement is not actually saying what they are. Moreover, insofar as these agential powers are essentially related to change, they are difference-​makers as well. But what they really are, he thinks, are either origins of pushings, pullings, teachings, heatings, generations, craft-​makings, curings, sickenings, end-​inclusive activities, and so on, which fall into the roughly defined families whose outlines I have traced in this section.



55 Cf. APo. II 12, 95b1–​13; Phys. IV 11, 220a18–​20; VI 1, 231b6–​10; DC III 2, 300a14.

196  Causality and Causal Explanation in Aristotle Other metaphysical worries still seem pressing, however, especially concerning the causal components of a transformation, being, or activity itself. Here some of the well-​studied problems concerning natural substance in the middle books of Aristotle’s Metaphysics become especially pointed, including Aristotle’s identification of natural substance with form, and of the matter with the living body. Simply put, in terms of our problem, if a natural substance really is form, as Met. VII 17 tells us, then form seems once again to lack explanatory value—​it simply is what we are inquiring about. But if it is not, and is rather the substance’s actuality in some more subtle sense, this makes the initial object of inquiry less clear. These are difficult issues, however, and so it is no accident that they have exercised commentators and appear to exercise Aristotle as well. I think, nevertheless, that they can be approached with greater clarity if we have a broader view of how the approach to the causes of substance fits within Aristotle’s scheme of causal explanation in general and in nature. A further difficulty that must be acknowledged, especially for his account of basic interactions, is that it appeals to a bedrock distinction between active and passive capacities among the elements. Like many of his claims about the elements, this looks like an empirical hypothesis, but it is not obvious what consequences a more accurate understanding of the basic kinds of matter, and their basic interactions, would have for the rest of his view. A final problem for the kind of causal realism Aristotle wishes to develop, perhaps most pressing for present purposes, is that recognizing these metaphysical connections and causal essences does little to address the epistemological worry that animates Hume and Kant and their successors: namely how we can, on the basis of our experience of contingent particular interactions, grasp these important but non-​evident connections among them and the individuals engaged in them. And this is indeed a problem: whatever Aristotle wants to say about the relations between agents and patients, or ensouled beings and their bodies, we as knowers seem to be directly confronted with contingent particular things that undergo various changes and transformations—​not essences, not capacities. Aristotle is sensitive to these worries as well, insofar as he thinks that the right account of causation must preserve the reality of the appearances, but still achieve some sort of profound understanding of them by way of their causes. Hume and Kant each have a response to this problem, and so does Plato. What is Aristotle’s?

PART III

E PIST E MOLO G Y

9 Coming to Know Causes 9.1.  Basic Questions about Grasping Causes According to the view described thus far, the distinctions in Phys. II 3 constitute an application of a general schema for fact explanation to a task of kind explanation for a broad class of stable kinds—​both natural and artificial—​ including transformations, beings, and activities. Considered as kinds, they have intrinsic causes, the grasping of which constitutes a grasp of a real definition or causal essence. These natural kinds have different causal profiles, however, which vary depending on the phenomenon in question, both with respect to their elements and the inter-​relations among them; an especially important distinction holds between what I have called origin-​dominant and end-​dominant profiles. This view would reasonably be described as a type of metaphysical realism about causes, whatever its virtues, defects, or ultimate plausibility. Now, when Aristotle introduces his views about causes and their importance, the context and aim are invariably epistemological: causes are important to discover, and causality important to understand, because it is by grasping causes that we gain scientific understanding (epistêmê) or wisdom (sophia). Nevertheless, for all that has been said, one might still maintain that Aristotle’s epistemological optimism is not justified, since, however true it might be that there are such stable kinds with real, causal essences, we are not in any better of a position with respect to them than we are with respect to separate Forms or ultimate material elements. For all we know, that is, most of our beliefs about what causes what might turn out to be false, and the things that appear to us to be causally basic principles might not be as they appear. We might develop reasonable and even true beliefs about stable natural kinds, but why should we think we can achieve any more profound or stable sort of insight about them, or that our beliefs have any epistemic advantage over those available to a Platonic inquirer? I have argued that many broad assumptions and statements about Aristotle’s theory of causes are inaccurate or incomplete, but for all that, Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0010

200  Causality and Causal Explanation in Aristotle causes themselves and their metaphysics, especially in particular cases, have not lacked for attention. By contrast, Aristotle and his commentators have had comparatively little to say about how we grasp causes. And yet, by explicating knowledge or wisdom in terms of grasping causes—​and consistently using a different cognitive word for the condition of grasping causes (e.g., labômen, gignôskein) than the one used to pick out the resulting “target” knowledge (e.g., eidenai, epistasthai)—​Aristotle invites us to ask what is distinctive about this grasp, and how it differs from, say, mere belief or opinion.1 How, then, according to Aristotle, do we grasp causes, and how do we grasp them in a way that answers to the demands of scientific understanding? How do we distinguish causes from necessary conditions or accidental concomitance? These are simple enough questions, and fair ones to ask on their own. Answers are especially needed, however, if Aristotle is to have a complete response to his predecessors, who, he thinks, besides their other mistakes, made causes epistemically inaccessible and (thereby) made nature scientifically unintelligible.2 What makes causes (on his account) intelligible in the strong sense required, in a way that is superior to the causal principles of his predecessors? What prevents us from having at best justified beliefs or hypotheses about causes? The most direct statements Aristotle makes about knowing the causes of things relate to his obscure notion of “induction” (epagôgê), which has been the focus of a long tradition of commentary. Commentators have also distinguished, on the basis of the APo. especially, different stages of inquiry, relating to the different types of “account” or definition Aristotle describes.3 Both topics are important, and I discuss them in the next sections. It should be clarified at the outset, however, that neither set of passages, even if they 1 In Phys. II 3, we do not know (eidenai) until we grasp (labômen) the Why of each thing (194b18–​ 20); in APo. I 2, we think we understand (epistasthai) each thing in the unqualified way when we think we know (gignôskein) of its cause that it is the cause, and that this cannot be otherwise (71b9–​ 12); in Met. I 3, we say we know (eidenai) each thing when we think we know (gnôrizein) its primary cause (983a25–​6). This feature of his repeated claims is only rarely discussed. Barnes 1994 does raise the question briefly in his commentary on the APo., in his note on 71b9 (90), as does Burnyeat 2011, 19ff. Barnes and Burnyeat agree that in APo. 71b9–​12, ‘ginôskein’ and ‘epistasthai’ must be taken to have different meanings. In Burnyeat’s gloss, the contrast is between “explanatory knowledge that p because q” and “the plain knowledge that p and the plain knowledge that q” (23). On that account, the question then becomes: “How do we acquire the plain knowledge that q? And how do we progress from there to the explanatory knowledge that p because q?” In general, however, perhaps since Aristotle himself does not give the question sustained treatment, it is not surprising that commentators do not raise the question independently either. 2 See § 2.1. 3 For an influential “three-​ stage” account of inquiry, see Charles 2000; for a critique, see Bolton 2018.

Coming to Know Causes  201 were perfectly clear or uncontroversial—​and they are emphatically neither—​ would give us a clear answer to these epistemological questions about how we grasp a thing’s causes, grasp that they are its causes, or grasp them in the appropriate way: their stated aims are different, and their bearing on those questions is partial and indirect, as I shall show in more detail (§ 9.2–​9.3). Nevertheless, even though Aristotle does not address the epistemological challenge explicitly, that challenge is directly related to his overarching project of making nature intelligible and an object of genuine scientific understanding, and to the ways in which he takes himself to have improved on his predecessors’ views. So it is reasonable to think that what he does say about causes, inquiry, and our cognitive powers should fit with his overall aim, and it will contain some indications of how he thought he could achieve this. I think two important theses can in fact be well-​established on the basis of what Aristotle does say. One is that there are important asymmetries between different types of causal phenomena: some types of cause, indeed some types of what I have called causal profiles, can be scientifically understood by means of more basic cognitive capacities than others. Another is that at least some causal profiles can be fully understood without going beyond the conceptual resources of our ordinary capacities for observation.4 There is thus a path from simple to complex, observable to abstract, which would allow Aristotle to say that we can come to understand causes in ways that his predecessors cannot. Before attempting to delineate Aristotle’s answer, however, we should once again clarify the question and what sort of answer we have reason to expect.

9.2.  Causes and the Two Images First, we should not underestimate the significance of these questions about the capacities and progress by which we come to grasp something’s causes. Aristotle’s own remarks about causal epistemology, as we shall see, are ambivalent in a way that straddles a philosophical divide, one which goes to the

4 This is not to say that the grasp is not an intellectual one, but rather that, in contrast to most causal profiles that will require intellectual operations such as inference and appeal to non-​observational concepts, some causal profiles will involve no inference and no non-​observational concepts. It is, of course, difficult to say just what the “conceptual resources of ordinary observation” are, both in general and for Aristotle; I discuss the difficulty further later.

202  Causality and Causal Explanation in Aristotle heart of the questions and puzzles that have animated the discussion of causality from before his time down to ours. By making our grasp of causes an act of the intellect which goes beyond what perception and experience provide, many philosophers invite us to see causation as a “secret connexion,” or an invisible “cement of the universe,” as distinct from the supposed “furniture,” which we can actually observe.5 This initially epistemological move in turn makes some form of metaphysical reductionism appealing, especially when paired with the empiricist idea that our most basic ontological commitments derive from perception. The epistemological claim is therefore just as much a part of what makes skepticism about the reality or metaphysical status of causation seem such a live option as any metaphysical thesis. We may call this position “Causal Intellectualism,” and as I shall suggest, it comes in a variety of types and strengths. On this score, Hume and Russell are in the same camp as Plato and Democritus. Indeed, it is by making the same kind of intellectualist assumptions that Russell famously dismisses causes, on the grounds that they must be the sort of thing that would be discovered by physicists if they were to be discovered by anyone.6 To borrow Sellars’s (1963) famous distinction between the manifest and scientific images of nature, on this approach, causes are to be found in the scientific image if they are to be found anywhere. Though it is an epistemological position, it goes hand in hand, and by no co-​incidence, with the general tendency to assume that causal facts somehow supervene upon more basic non-​causal facts or states of affairs.7 If we suppose that basic facts are non-​causal facts, and that perception is on the whole conceptually constrained, then it is natural to assume that any causal knowledge we have results from intellectual acts that transcend what is given to us in perception. The alternative approach is to claim that causes are instead or in addition to be found in the manifest image—​that causal connections are somehow

5 The point is explicit in Hume, as he specifies causation as the only relation that “can be trac’d beyond our senses, and informs us of existences and objects, which we do not see or feel” (Treatise, 75). 6 Russell 1912. 7 I do not mean to suggest that Plato thinks that causal facts supervene on non-​causal facts, of course, and one might also wonder whether it is quite appropriate to think of Platonic forms and participation in terms of an exclusive and exhaustive distinction between causal and non-​causal entities. Nevertheless, without attempting to settle long-​standing debates about the nature of Platonic forms, I think it is reasonable to assume, since they are described in the Phaedo as being whatever they are “themselves by themselves,” among other features, that they are what they are independently of any relationship they bear to individuals that come to participate in them. (See passages in the Phaedo cited earlier, p. 49 n. 23.)

Coming to Know Causes  203 evident to us in a way that does not require making theoretical posits or otherwise transcending what we get from perception and experience. We may call this position “Causal Observationalism”; on the whole it seems to be a minority view, and it is certainly less developed than Intellectualism. It, too, however, admits of a variety of types and strengths, and it likewise opens the door to a kind of skepticism about causality, though of a different sort.8 Perhaps its most well-​known exposition in recent works comes from a few suggestive statements by Anscombe 1971: “[Hume] confidently challenges us to ‘produce some instance, wherein the efficacy is plainly discoverable to the mind, and its operations obvious to our consciousness or sensation’. Nothing easier: is cutting, is drinking, is purring not “efficacy”? (10). Anscombe’s remarks are an ad hominem reply to Hume and indeed Russell, aiming to turn the tables by arguing that observing causation is as common and unproblematic as observing objects like billiard balls, and so neither more nor less acceptable by empiricist standards. This is a neat idea, but Anscombe’s discussion does not range much past the ad hominem point she wishes to make, and focuses more on the thought that ‘cause’ is a general term that gathers together these species of action, but that would not make sense in a language without them (9).9 More recent work in this context focuses on the degree to which the contents of perception do or do not include causal concepts or their equivalent.10 However, although some philosophers might argue that the observability of causal relations supports a kind of realism, unless there is good reason to think that the kinds of causality we can observe (i.e., in the manifest image) are also found in the scientific image, the skeptic may be unfazed. Indeed, this view can be used to underwrite the thought that causation is a mere “folk” concept, useful to be sure, but not necessary for describing the way things really are.11 The epistemology of causation, then, is central to the philosophical disputes that tend to arise about causation more broadly, even though the topic receives less direct attention than questions about causal concepts or 8 By Causal Observationalism I mean mainly the view that causal connections are somehow evident to us in a way that does not require theoretical posits or inferences. Sellars’s own view of the manifest image is more complex and nuanced in ways that are not relevant for these purposes, but overall I think the distinction is useful and pertinent. 9 See also Godfrey-​Smith 2009. 10 See, e.g., Butterfill 2009, included in an issue devoted entirely to questions about the contents of perception. 11 See, e.g., Norton 2003.

204  Causality and Causal Explanation in Aristotle metaphysics. Moreover, they are central to understanding what it means to satisfy the desire to understand that Aristotle takes to be part of our human nature. Indeed, on almost any robust account of knowledge, the characterization of the knowledge we are meant to acquire comes along with, at least in outline, an alteration in our view of the familiar array of things and relations with which we began. Once we understand atomism or one of its modern descendants, for example, objects on the human scale appear to be dependent in a new way, the consequences of which we must work out. Once we understand Platonism, the domain of familiar perceptibles appears likewise to be diminished, though in a very different manner. How, then, do the elements of the manifest image look to someone who has attained the Aristotelian achievement of a causal understanding of the natural world? These distinctions are useful for clarifying Aristotle’s position, as well as his critiques of his predecessors. As an optimistic causal realist, Aristotle wishes to affirm that we grasp causes in the scientific image but also to make it clear how we can do so in a way worthy of the name of understanding, since placing causes in the scientific image opens up the possibility of a sharp divide between the way nature appears and the way it really is. On the one hand, accordingly, he associates causal knowledge with thought and universals—​that is, with intellectual achievements that clearly transcend what we can do with our perceptual capacities. Nevertheless, a good way of understanding his rejection of a special ontology for causation is as a rejection of the idea that there are separate entities proper to the scientific image which serve to explain the things in the manifest image, in part because appealing to a special ontology opens up too wide of a gap between our epistemic starting points and our goals.12 He thus wants to claim that causal knowledge is both profound and accessible to us, given our epistemic starting points. He embraces the motivations that lie behind both Causal Intellectualism and Causal Observationalism, and it is not clear how he can reconcile them. I think, in fact, that Aristotle’s remarks about grasping causes, and his remarks about our epistemic access to the objects of natural scientific inquiry more broadly—​namely, natural change and substance—​indicate a coherent position that meets his own desiderata and that, together with his other claims, constitutes a philosophically important position that deserves a hearing. In the next few sections I will delineate the position and then show



12 See especially Chapter 2 and § 4.1.

Coming to Know Causes  205 (Chapter 11) how it fits with Aristotle’s anti-​reductionism, as well as examine its strengths and weaknesses. The view has two broad features that distinguish it from what Aristotle takes to be those of his predecessors, as well as from most modern views. First, rather than assuming a single type of cognitive capacity or activity to be distinctive of grasping causes, Aristotle thinks there is a range of such activity. This should be no surprise, given his conceptual and metaphysical pluralism, but what is striking, as I shall argue, is that his distinction between what is “more knowable to us” and what is “more knowable without qualification” applies not just to various facts and kinds but to the modes of causation themselves: some types of causality, and therefore some types of causal profile, are “closer to perception” than others. Thus, whereas from most presentations it would appear that Aristotle has an epistemically “flat” picture, according to which all the various types of causes are on a par and grasped in the same way, I shall argue that on his view there is instead a gradient, corresponding to differences in the cognitive requirements for grasping them. Second, and relatedly, I shall argue that on Aristotle’s view our epistemic progress is not a move from a stage that lacks causal content or concepts to a stage in which such concepts are introduced, but rather from stages that involve certain kinds of causal content and concepts to others that are more sophisticated, more abstract, and thus require more developed cognitive tools. Causality of certain types is nevertheless present in the manifest image right from the start, as a kind of foothold from which we can advance to the types that are necessary for full scientific understanding. He thus subscribes to some form of what I have called Causal Observationalism, though in various ways his position and approach must look different from modern approaches which focus on the role of causal concepts in perception, language, or ordinary judgment. After developing these two aspects of his view, and drawing out their consequences for the epistemological challenges I think Aristotle has raised, I will illustrate how the view is supposed to work by looking at what he says about a particular “natural kind,” namely blood.

9.3.  A Problem of Induction Aristotle’s own remarks about how we come to grasp causes are spare but suggestive, and they include some of the most perplexing and controversial

206  Causality and Causal Explanation in Aristotle passages in his extant works. On the whole, they are ambivalent between what appear to be broadly rationalist and broadly empiricist tendencies, and so they have been interpreted.13 This is to be expected, in fact, since so many of his views about knowledge and science are framed in terms of a picture of cognitive progress, from its narrowest beginnings to its highest achievement, sometimes emphasizing the former, sometimes the latter. Many of the difficulties center on three important but difficult passages in which he describes our progress from perception to knowledge, or, in his terms, from what is “more knowable to us” (gnôrimôteron hêmin) to what is “more knowable by nature” (gnôrimôteron phusei), or “more knowable without qualification” (gnôrimôteron haplôs).14 (For brevity I will use ‘Familiar’ for the former and ‘Intelligible’ for the latter.) The process, or an instance of it, is referred to in APo. II 19 as “induction” (‘epagôgê’, 100b4), in the classical sense of moving from particular to universal.15 Famously, he elaborates his opening claim of the Metaphysics—​“All human beings, by nature, desire to know” (980a1)—​by describing a progression from perception through imagination (phantasia), memory (mnêmê), experience (empeiria), craft (technê), and reasoning abilities (logismois). The decisive part of that progression is the transition to craft, which is characterized in terms of knowing the Why (to dioti) or the cause. The description of our progress is very compressed, however, and Aristotle does little more than indicate that it is by grasping causes that we move from experience to craft: The other animals, then, live by appearances and memories, and have a small share of experience. But the human kind also lives by craft and reasoning. And for humans, experience comes to be out of memory; for many memories of the same thing result in a capacity for a single experience. (Met. I 1, 980b25–​981a1) And craft (technê) arises whenever, out of many considerations [ennoêmatôn] of experience, a single universal grasp [hupolêpsis] comes to be concerning things of the same sort. For, to have a grasp [hupolêpsis] that this benefitted Callias when he was sick with this illness, and also Socrates, and 13 See the references given with respect to particular texts and issues in what follows. 14 See APo. I 2, 71b33–​72a5; Top. VI 4 141b3–​142a16; Phys. I 1, 184a16–​21; De An. II 2, 413a11–​16; and Met. VII 3 1029b3–​12. 15 In contrast, that is, with the more modern sense in which induction involves inference from previously observed particulars to unobserved particulars. Cf. Top. I 12, 105a13; the ‘particulars’ Aristotle is contrasting with universals may be either individuals or lower-​level types.

Coming to Know Causes  207 thus individually for many people, is experience; but to have [a grasp] that it benefitted everyone of this sort, marked off by virtue of one form, suffering this illness—​for example phlegmatic people or bilious people [or those] suffering from bilious fever—​belongs to craft. (981a5–​12)

Overall, these passages appear to commit Aristotle to the view that we grasp the causes of things through a kind of induction rooted in experience—​ it is indeed a locus classicus for the picture of Aristotle as some kind of empiricist—​but few details are provided, and in fact a Platonist might well agree with what Aristotle has said so far. After all, Plato famously provides a picture of ascending cognitive progress from images to intelligible Forms in the middle books of the Republic.16 The passage does, however, suggest a gap between the cognitive powers associated with observation and experience, on the one hand, and our ability to know causes, on the other, since the latter is associated with a stage that is distinctive of humans. Everything else, including experience, is shared with at least some animals.17 So despite its apparent empiricism, this passage is compatible with and in some ways even invites a strongly rationalist interpretation of causal knowledge. Experience aligns with perception and pertains to particulars, whereas craft aligns with knowledge, wisdom, and reasoning, and pertains to universals.18 The move from experience to craft, however, is only enigmatically described, and it presents substantial puzzles.19 However we interpret them, these passages connect the questions of cognitive progress with different psychological states and capacities. Thus, the capacities described in Met. I 1 starting from perception and running 16 See Gasser-​Wingate 2021 for an attempt to say exactly how Aristotle’s empiricism makes a stronger claim on behalf of perception. 17 Assuming, as is the consensus view, that when Aristotle says other animals have only a small share of experience, he means that they do at least have some, rather than that they do not really have any. See Hasper and Yurdin 2014, 143; Alexander of Aphrodisias, In Met. 4, 13–​26 Hayduck, argues for the latter view. 18 Other texts support this broad alignment of objects and faculties, in particular Topics VI 4, 141b3–​14, and APo. I 2, 72a1–​3, which both explicate the distinction between what is more knowable to us and what is more knowable by nature in terms of the objects’ relation to perception. Thus, “I mean by ‘prior and more knowable to us, on the one hand, the things that are closer to perception, whereas [I mean by] ‘prior and more knowable simpliciter’ the things that are farther away” (72a1–​3). 19 For example, Aristotle says that craft arises when a single grasp (hupolêpsis) comes about from the many ennoêmata of experience; ‘ennoêmata’ is a hapax, and it is unclear whether Aristotle is referring to components of experience itself or more sophisticated cognitive reflections on experience (see Cambiano 2012, 16). He uses ‘hupolêpsis’ to refer both to experiential judgments and to the explanatory judgments derived from experience (981a8–​12), but they have different types of object, since experience is cognition (gnôsis) of particulars, whereas craft is knowledge of universals (981a15–​17).

208  Causality and Causal Explanation in Aristotle through experience pertain to particulars, while capacities and states, including knowledge, wisdom, craft (technê), and reasoning, are aligned with universals. In the same chapter Aristotle describes common opinions about knowledge and wisdom. We (evidently) think knowing and understanding (to eidenai kai to epaïein) pertain to craft rather than experience (981a24–​ 25), and accordingly that experts are wiser than men of experience, since the former know causes and the latter do not (981a26–​28). For the same reason, we consider master craftsmen to be more honorable, to know better, and to be wiser than manual laborers (981a30–​b2); they are wiser, because they have the account themselves (to logon echein autous) and know the cause (tas aitias gnorizein). We do not consider any senses to be wisdom, even though they are authoritative means of knowing (gnôseis) particulars, since the senses do not tell us the Why of anything—​they do not tell us, “for example, why fire is hot, but only that it is hot” (981b10–​13). It is difficult, however, to assess what Aristotle means by aligning Familiarity with perception, since his word ‘aisthêsis’, among its variety of uses, can seemingly cover anything from basic sensory discrimination to a rather robust sort of empirical judgment.20 The scope and limits of our powers of perception are thus clearly important to Aristotle’s conception of our epistemic starting points. Far less clear, however, is the extent to which he has strong views about what more recent empiricists and philosophers of mind would call the content of ordinary perceptual experience, at least as it concerns the starting points of inquiry. His own discussion in the De Anima of the contents of perception, for example, despite the importance of perception for his overall approach to inquiry, is notoriously thin—​it has not been clear to commentators even how Aristotle thinks we have perceptual cognition of objects rather than just sensory qualities, despite the fact that he clearly thinks we do, or whether he seriously raised such a question for himself.21

20 And likewise for its associated verb, aisthanomai. For example, in De Motu 7, in describing the last step of practical reasoning prior to movement, he seems to ascribe a capacity to state “this is drink” to each of the three capacities of perception, imagination, and thought (701a29–​36); cf. DA III 7, 431b5–​6. More generally, aisthêsis is a kind of cognition (gnôsis, APo. II 19, 99b38, GA I 23, 731a33, Met. I 1, 981b11). But Aristotle also holds that perception is characteristic of all animals, rational or not, and that the primary type of “kath’hauto” perception is, unlike thinking, immune to error, in a way that suggests that its content is less sophisticated than an ordinary judgment that can be true or false (DA III 3, 427b8–​13). 21 The topic is rarely broached directly; see, most recently and fully, Gasser-​Wingate 2021, especially ch. 4, and Caston unpublished.

Coming to Know Causes  209 To elucidate the kind of cognitive progress from perception to understanding that Aristotle describes, commentators have typically turned to what looks like a parallel description of cognitive progress at the end of APo. II 19, which also describes some sort of induction that begins with perception, memory, and experience and ends in an intellectual grasp of first principles (nous). Given the famous obscurity of that passage, this is a somewhat desperate hope, and interpretations have likewise split between more empiricist and more rationalist readings.22 Even if the passage were perfectly clear, however, there are good reasons to be cautious in comparing them. For one, APo. II 19 makes no mention of causes but is rather about the search for first principles (archai) of demonstration, in an explicit attempt to counter the foundationalist worry raised at the beginning of the APo., namely that if demonstrative knowledge were the only kind of knowledge, we would not have knowledge of the first principles of demonstration, which is unacceptable.23 And, indeed, it is difficult to see how the description given there of our progress toward first principles would be relevant to discovering the causes of the kinds of phenomena Aristotle thinks have causal explanations, nor does it seem even potentially illuminating to say that the efficient cause of earthquakes or the final cause of lungs “makes a stand” from among undifferentiated particulars, the way universals are supposed to arise on that picture. Just as causes are not mentioned in the APo. account, Met. I is not concerned with worries about demonstration and its foundations. Similarly, APo. II 19’s invocation of the special state or capacity of intellect (nous) for first principles is no part of the discussion in Met. I. Rather, the cognitive achievement of grasping the Why of something in the Met. I passage, craft (technê), is more analogous to what the APo. describes as demonstrative knowledge, that is, knowledge mediated by grasping a middle term naming the cause—​or perhaps to the whole cognitive structure of understanding (epistêmê), which consists of both knowing first principles and

22 The view often taken to be traditional treats nous as a kind of intellectual “intuition,” in response to which many modern interpretations have responded with more empiricist readings. Barnes 1994 (commentary ad loc.) argues convincingly that nous is being treated as the state of grasping first principles rather than a process of coming to grasp them, but this does not exclude it also being treated as the ground or capacity, the way ‘vision’ refers to both the capacity and the act (cf. Kosman 1973, 385). He goes so far as to say that “Nous has no philosophical importance in APst” (270). Irwin 1988 defends the traditional interpretation of nous as intuitive knowledge. Besides the commentaries of Ross 1949 and Barnes, see Tuominen 2010 for a clear discussion of the chapter and its difficulties, and Charles 2000, § 10.6. 23 See especially I 3, 72b18–​25; the problem is recalled at II 19, 99b17–​22.

210  Causality and Causal Explanation in Aristotle having demonstrative knowledge of what follows from them.24 So when it comes to answering the question of how we come to grasp causes, we should be wary of relying on parallels between Met. I and APo. II 19.25 In fact, if we were to start over and simply ask what the APo. has to say about knowing causes, our approach would be very different, and we would hardly consider II 19 the place to look. Instead, we would look to chapters I 2, I 31, I 34, and II 2, in which Aristotle writes more directly about coming to grasp something’s cause or middle term, as well as perhaps II 8–​10 and II 13, in which he writes about seeking or determining essences. On the whole, these chapters do not tell a unified story. They agree with the claim in Met. I that perception does not give us the Why of something, but I 31, 34, and II 2 also tell us that perception can bring it about that we grasp the Why more or less immediately, and rather suggest that grasping causes can in some cases be a cognitively simple act, even an automatic one.26 II 8–​10 and 13, on the other hand, do describe more intellectually sophisticated activities connected with the essences of kinds, but they do not appear concerned to tell us how we can come to know what properties are part of a kind’s essence.27 In sum, those passages of the APo. 24 Most explicitly and prominently in I 13, and II 2–​3. We might argue, following Kosman 1973, § VI, that induction is simply the obverse of demonstration, and that nous is both the ground and achievement of induction (390), so that moving from a grasp of the fact to a grasp of the cause would, after all, simply be an act of nous. While his overall interpretation has found favor, this part of it is hard to square with Aristotle’s tendency in the Post. An. to reserve ‘nous’ for first principles only and to distinguish the cognitive activity of moving from the fact to the reason why from induction and nous, rather than to assimilate them. Likewise, I 18 discusses induction with reference only to universals, not causes. For a critique of Kosman’s approach, see Ferejohn 2009. 25 Likewise, in terms of some of the questions I raise here, issues pertaining to justification or the difference between mere belief and something more authoritative often focus on the status of nous and its relation to first principles in APo. II 19; see, e.g., Irwin 1988, ch. 7; M. Frede 1996. Again, however, the issues raised there may well be idiosyncratic to the knowledge of principles and to the picture of demonstration being developed there, and we cannot assume the discussion is relevant to the broader challenge of understanding our grasp of causes in general. 26 APo. I 31, 87b28–​88a2, repeats and expands upon the claim that perception does not reveal the Why of something because we do not grasp universals through perception; cf. I 18. A few lines later, however, at 88a9–​17, he seems to claim that in some circumstances, perception is sufficient for grasping a Why, and in II 2 Aristotle even states that in some circumstances perception yields both the fact and the Why at the same time and is sufficient for knowing the universal cause (90a26–​30); he uses the eclipse example in both passages. He repeats this claim at II 8, 93a17–​18. The passages are brief, however, and Aristotle may simply be leaving out a description of the higher cognitive work involved; see § 10.3. In I 34, however, Aristotle names the capacity for grasping a middle term quickly as “quick wit” (agchinoia), a kind of non-​rational talent (eustochia) which seems to be cognitively simple, far removed from the high achievement of human understanding, and distinct from both induction and nous—​‘eustochia’ indicates something close to lucky guessing. (Pacius 1597, 322–​23, glosses agchinoia as a kind of quick, correct guessing, conjectatio). Quick wit is also defined at EN VI 9, 1142b2–​6 as a kind of eustochia, which is glossed there as something that does not involve reasoning (aneu tou logou); both are again distinguished from nous in that passage. 27 It seems instead that in these chapters Aristotle is describing methods for arranging and working out the relations between various properties already known to be scientifically relevant to a kind,

Coming to Know Causes  211 which do deal with knowing causes invoke a whole range of cognitive activities, some sharply distinct from ordinary perceptual cognition, but some quite close to it. We must also be cautious with those passages since, as we have seen (§ 3.3), Aristotle’s work on scientific explanation in the APo. is insensitive to key aspects of his mature thinking about causality in natural science. Finally, the opening chapter of Phys. I, after stating that understanding involves looking for “principles, causes, and elements” (184a2–​3), also describes our progress as moving from what is more knowable to us to what is more knowable by nature. What is familiar to us, he says at the beginning of I 1, are things that are commingled or “confounded” (“sugkechumena”), and so we must proceed from universals to particulars, since “the whole is more knowable in relation to perception,” and the universal is “a sort of whole” (184a24–​25). The whole passage has vexed commentators since antiquity.28 The statement that we move from universals to particulars in the study of nature is especially obscure, since APo. II 19 makes the reverse claim that we progress from particulars to universals.29 Aristotle’s illustrations are suggestive, but obscure in the extreme: “This same thing also happens in a certain way with names in relation to the account; for they indicate a certain whole and in an undivided way, like the circle, but its definition (horismos) divides it into the particulars. And children at first call all men fathers and all women mothers, but later they distinguish each of them” (184a26–​b13). The example of definition as analyzing a whole into parts is especially significant, but the sense in which what is presented to perception is a kind of universal has been a source of confusion and controversy.30 Since Phys. I proceeds to locate three principles of change—​matter, form, and privation—​as foundational concepts for natural science, it may be that he does not mean to describe ordinary scientific progress at all (e.g., coming to grasp the function of the lungs), but rather grasping the ultimate concepts that lie at the

perhaps for the sake of constructing demonstrations or working out which properties are constitutive of that kind. Cf. Barnes 1994, 240–​48. 28 See Ross 1936, 456–​58, for a clear account of the perplexities, as well as Falcon 2018 and Menn 2019 for fuller commentaries and interpretations. 29 100a15–​b5; likewise Met. I 1. But see Bolton 1991, who maintains that the same sense of ‘universal’ (katholou) is being used in the two works. 30 On this question, and especially the sense in which the “wholes” with which we are initially presented in perception are “confused” or “confounded,” see especially Falcon 2018, §§ III–​IV, and Menn 2019.

212  Causality and Causal Explanation in Aristotle foundations of any branch of knowledge. If he does instead, or in addition, mean to describe our ordinary grasp of causes, there are still several ways of interpreting the claim that what is more available to perception is the whole. He may mean that we move from observing general groupings such as, say, plants and animals, and then progress toward distinguishing and understanding “particular” species (one possible gloss of his obscure statement that our initial state resembles the way children begin by calling all men ‘Father’), or that we are, in a way, presented with the natural world all at once, whose various components or strata—​basic versus compound bodies, types of transformation, and so on—​are only singled out and understood individually with great effort. Alternatively (but not exclusively), he may mean that when looking at natural kinds or individuals, we are presented with the whole careers of various beings with their complex arcs of coming-​to-​be, existence, engagement in various activities, and passing away, the elements of which and their causal connections to one another must be discerned. He may mean all three things—​after all, for each of these ways of describing our starting point as a confused grasp of naturals kinds “as a whole,” the ultimate goal is the same: to discern the role of form and matter in constituting the natures of various kinds, individually and in general. It is difficult, then, to extract any kind of detailed account of how we know something’s causes from Aristotle’s brief and confusing remarks about induction, other than that it involves a progression from what is more knowable to us, associated especially with our capacity for perception, to a grasp of causes and principles that are supposed to be more knowable by nature or unqualifiedly, and which involve more sophisticated intellectual capacities; and his explicit remarks in the APo. muddy the waters further. Further, only some of these remarks clearly pertain to causality rather than ultimate principles, and so their connection to the aims of natural science is not clear.

9.4.  Stages of Inquiry and Their Associated States or Capacities To clarify the picture, then, it would be helpful if we had a clearer, independent understanding of what is Familiar—​of where we begin with respect to nature—​and how we progress from there. In this connection, there is another set of important passages in which Aristotle discusses cognitive progress in terms that pertain to causes, also

Coming to Know Causes  213 from the APo.: these are the remarks which have been the occasion for the sustained discussion among commentators about “stages of inquiry” mentioned earlier. In APo. II 1, Aristotle says that we inquire into four things: the “fact” (‘hoti’), the Why (‘dioti’), “if it is” (i.e., if there is a certain kind K), and what it is (its essence).31 These objects of inquiry are evidently sought at different stages: if we have the fact, we seek the Why; if we know a certain kind exists, we seek its essence. In II 2, these four questions are then reduced to two: we seek to know either whether there is a “middle term” (i.e., a term for a cause by which it can be demonstrated that some major term is predicated of some minor term), and what that middle term is. That is, abstracting away from the difference between causes that do and those that do not constitute the essence of what they explain, we seek first (1) whether there is a cause of a certain fact or of a certain kind, and, having established that there is, we seek to know (2) what that cause is.32 Aristotle thus distinguishes at least two stages of inquiry for facts and kinds: a stage at which we know that a certain fact obtains or a kind exists and has a cause (I shall assume he means an intrinsic, i.e., kath’hauto cause), and a stage at which we seek to discover the cause of the fact or kind. The “fact” stage is evidently preceded by a stage at which we do not yet know whether the fact or kind has a cause that can be discovered, and there has been a great deal of controversy as to how we should characterize this stage. These issues have, further, become intertwined with difficult questions about other statements in the APo., especially in chapters II 8–​10, in which Aristotle discusses definition, both in general and in the context of a demonstrative science.33 An important feature of this schema on which commentators agree is the distinction between a pre-​explanatory and an explanatory stage: the latter step involves grasping causes and essences, while the former involves a grasp on the phenomenon which is robust enough to constitute knowing that the phenomenon is scientifically investigable—​in Aristotle’s terms, minimally, that it is not a co-​incidental phenomenon such as those due to chance. This 31 89b23–​35. 32 89b36–​90a23. 33 Among the difficulties is that it is unclear how essences of kinds can be middle terms, and whether Aristotle is consistently thinking about them in that way in these passages. On these issues and on stages of inquiry in general, see especially the commentaries of Ross and Barnes on APo. II 1–​2 and 8–​10, as well as Bolton 1987, 2018; Charles 2000; Bronstein 2016; and the references there. I think that this intertwining of questions about stages of inquiry and types of definition is to some extent unfortunate, since the degree to which the types of definition in II 10 are supposed to correspond to stages of scientific inquiry is already unclear.

214  Causality and Causal Explanation in Aristotle distinction appears to be borne out across other works, including natural-​ scientific works. The pre-​explanatory stage is evidently one in which we are acquainted with things that are more Familiar but less Intelligible than those at the explanatory stage. One difficulty for understanding the nature of these stages is that Aristotle is often unclear as to the “us” to which his claims are indexed, when he speaks about what is “more knowable to us.” For more detail, commentators have looked to his writings about particular branches of natural science, concerning what things are evident or apparent at the outset of inquiry. Those discussions are very rich and introduce different sorts of complexity for the notion of Aristotelian appearances. Sometimes, in these works, he appears to be describing what is Familiar as what is available to ordinary human perceptual faculties and their range of sensitivity;34 in other places, slightly differently, he seems to indicate a range of distinctions or concepts in use in everyday life.35 Still elsewhere, however, he seems to be describing the specified starting points for a scientific investigator who is already some distance down the path of inquiry.36 Acquiring a pre-​theoretical grasp that a certain phenomenon constitutes a genuine and scientifically explicable fact or kind can be an achievement, not a given. These different possibilities for understanding the pre-​theoretical stage have led to starkly different interpretations, especially when commentators come to those key texts about induction described earlier, as well as other passages about philosophical and scientific method.37 Of course, scientists must start somewhere, too, and they often depend both on the distinctions of ordinary experience and data of more highly experienced non-​scientists for

34 E.g., APo. II 19, 99b32–​100b5; Top. VI 4, 141b9–​14. 35 E.g., Met. VII 3, 1029b3–​12; EN I 7, 1098b27–​29. 36 E.g., APr. I 30, 46a17–​27; and HA I, especially in the context of the methodological remarks at I 6, 491a7–​26. 37 A well-​known division is between those who interpret APo. II 19’s account of induction as an account of concept formation for individuals and those who interpret it as describing the path of scientific inquiry. The difference, in large part, is due to lack of clarity about the “starting points” Aristotle has in view; see Barnes’s commentary ad loc., and Tuominen 2010. Likewise, the “commingled wholes” of Phys. I 1 have been interpreted as a description of the data of ordinary observation or perception (e.g., Charlton 1992, 52), and as the dim grasp on nature attained by early investigators like Plato and the Reductionists (Menn 2019). Parallel controversies run throughout discussions of Aristotelian “endoxa” and the “phainomena” with which inquiry is supposed to start—​indeed, they intersect, since commentators also dispute whether the appearances in natural science include things like the theories of one’s predecessors (the locus classicus is Owen 1961; for a clear treatment and reassessment, see especially D. Frede 2012).

Coming to Know Causes  215 their starting points, so the boundary between specialist and non-​specialist starting points is bound to be fluid.38 These distinctions between stages of inquiry are therefore helpful for framing broad ideas about epistemic progress in Aristotle. However, there are many aspects of these and related claims Aristotle makes in the APo. that are obscure and controversial, and many of the details are closely related to the picture of demonstrative science Aristotle is developing there. Once again, it is an open question whether and to what degree the theoretical claims about demonstrative science from the APo. can and should be applied to all Aristotelian science, especially natural science.39 Since I have also argued that the causal schema of the APo. is not the same as the one we find in the Phys., and since the APo. says very little about natural science as such (i.e., the science of being-​qua-​subject-​to-​change) and nothing about the hylomorphic understanding of natural beings and transformations, we should look independently at what Aristotle says about different stages of knowledge or contexts of inquiry in the works that do make use of the same concepts and schemata as the Phys. What these explicit claims and the debates among commentators do indicate is that problems concerning our knowledge of causes for Aristotle should be framed in terms of his views about the relationships between our cognitive goals, our cognitive starting points, and the cognitive capacities by which we are supposed to be able to make the transition between them. We must understand our grasp of causality in terms of both (1) the psychological states and (2) the epistemic stages of our cognitive progress. It would be helpful, then, to find evidence pertaining to these elements in works that also make use of the conceptual framework he develops for natural science. Aristotle clearly thinks that nature is scientifically intelligible because we have adequate starting points in our perceptual experience of particulars, from which we can proceed to knowledge of universal causes and principles. He also clearly thinks that this optimistic picture of successive cognitive capacities is intertwined with a picture of the stages of scientific progress, and that, for various reasons, his predecessors cannot tell a similarly optimistic

38 See, e.g., DC III 4, 303a20–​24; and NE I 7, 1098b3–​6, which appear to treat the notion of an epistemic starting point as both fluid and domain-​relative. 39 Indeed, Aristotle’s two examples of inquiry in APo. II 2, which are meant to elucidate the claim that we seek either whether a phenomenon has a middle term, and what that middle term is, are the

216  Causality and Causal Explanation in Aristotle story that connects our starting points to our goals on the basis of their favored ultimate principles. Nevertheless, while Aristotle generally associates the starting points of our progress with perception and particulars, and the endpoints with thought and universals, it is not clear how sharply he intends to draw the contrast. Sometimes he seems keen to emphasize the differences between the capacities that grasp individuals and those that pertain to universals and to the Why of things—​thus looking like more of a “rationalist”—​while at other times he seems to think perception or observation can accomplish a great deal of sophisticated cognitive work—​looking like more of an empiricist.40 In any case, so much of what he says about our epistemic progress is at such a level of abstraction that it is difficult to see how it is supposed to apply to the task of understanding causality in nature and natural kinds. We thus need a better way of getting a more precise grip on his ideas about the relationship between our cognitive capacities and our cognitive goals as he understands them. Since I have so far been describing what I take to be the endpoints of inquiry as the real causal definitions of natural transformations, beings, and activities which are grasped by the natural scientist, we can be more precise about the cognitive task at issue. The movement from the Familiar to the Intelligible that consists in getting a causal understanding of some phenomenon should be described accordingly as a move from (a) a pre-​theoretical account of a transformation, being, or activity which has intrinsic causes to (b) a theoretical grasp of its causal definition. However we should characterize the number and nature of stages of Aristotelian inquiry, then, it is this last transition that is at issue here.

eclipse and harmony as a ratio between high and low. Neither of these phenomena falls within the purview of natural science as Aristotle conceives it. 40 The difficulty is nicely compressed in his well-​known claim that “even though the particular is perceived, perception is of the universal, for example of man, but not of Callias the man” (APo. II 19, 100a17–​b1).

10 Causality and Epistemic Asymmetries 10.1.  Manifest Causes and Basic Asymmetries We should start by noting just how much of what we need to grasp as natural scientists seeking causes is observable, and just how much of what other views consider to be unobservable is, for Aristotle, open to view, since he seems to begin with a rich conception of the manifest image. Further, there is good reason for thinking that some types of cause, and some types of causality, are “closer to perception” than others. First, Aristotle thinks that necessarily, anything subject to change is necessarily enmattered, and that the generation and destruction of natural (hylomorphic) compound entities are grounded in perceptible bodies (GC II 1, 328b32–​33, 329a27–​b3). This means that all natural change involves a connection to bodies that are in principle observable. He further thinks, as we have seen, that insofar as the objects of natural science are either changes or subject to change, they all have efficient causes, and many have final causes, such as the activities of living beings. Failure to make this connection is one of the faults he attributes to the Platonists. Now, efficient and final causes are, at least in favorable cases, open to observation. Efficient causes, as we have seen, are often substances with agential capacities, constituted as such in basic cases by observable properties such as heat, while final causes are in general the endpoints of observable change and the manifest activities of beings expressing their natural capacities.1 The observational “data” of the Historia Animalium, indeed, are a catalogue of the observable behaviors of animals and their parts, on the basis of which the causal explanations of the PA are to be framed.2 These facts constitute the basis of Aristotle’s “reduction” of causal inquiry in nature to a search for efficient and final causes, which I have interpreted as the claim that for natural kinds, either an efficient or a final cause will be the primary cause of a thing’s 1 See especially §§ 6.3, 6.4, and 7.2. 2 HA I 6, 491a7–​11; see Lennox 1991.

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0011

218  Causality and Causal Explanation in Aristotle being or coming to be [F]‌and so occupy primary position in its theoretical definition.3 Where efficient and final causes are unobservable, it is normally because they are either very far away, or very small, or rarely encountered, not because in principle (categorially) they need to be grasped by a faculty other than perception.4 Matter and the formal causes which function as the endpoints of transformations may also seem to be generally observable, but there is an important difference. At least in the case of substance, what we observe and interact with are individual hylomorphic compounds, rather than form and matter or actuality and potentiality—​these must be discerned and separated out by thought—​matter especially, since in its own right it is somehow indefinite and does not appear to be observable in the same way that, say, heat is.5 Grasping the formal essence and matter of a natural kind thus seems to require a kind of abstraction that is not required in other cases, including for grasping the activities that constitute its end. This is, I think, a more significant point than it looks, but, of course, it does not entail that efficient and final causality is more manifest than formal or final causality, only that the entities playing these causal roles are themselves observables. The significance is rather that, however abstract or difficult to grasp a thing’s essence or matter might be, if it is a natural kind subject to change, its causal profile is anchored in a primary cause which is something observable, at least in principle. The elements of this interpretation can in fact be grounded in a general principle that Aristotle seems to hold: if something is essentially perceptible (i.e., an enmattered entity subject to change), its primary cause must be perceptible as well.6 If this were not the case, then since a definition specifies what a thing is, it would be possible for something essentially perceptible to be wholly defined in terms of things that are essentially non-​perceptible. And this is one of Aristotle’s key complaints about the Platonists: they wish 3 See Chapter 6. 4 See, e.g., DC I 3, 286a3–​7; PA I 5, 644b22–​35. 5 I will return to these issues of observability later. 6 Indeed, this claim is part of a general thesis about appropriate explanatory principles which he states in DC III 7, where he is critiquing his predecessors’ views about the generation of the elements, just prior to making his well-​known statement that the phenomena in natural science are ultimately answerable to perception: “It follows that in speaking about the appearances they speak in a way that does not agree with the appearances. The reason for this is that they do not grasp the first principles correctly, but rather wish to lead all things back in relation to certain predetermined opinions. For one needs, presumably, perceptible [principles] for perceptible things, but eternal [principles] for eternal things; and likewise the principles of perishable things are perishable, and in general, things of the same kind as their subjects” (306a5–​11).

Causality and Epistemic Asymmetries  219 to account for things that are essentially changing in terms of essentially non-​perceptible and therefore unchanging entities, which for Aristotle is equivalent to explaining essentially perceptible things in terms of essentially non-​perceptible ones.7 The plausibility of the latter inference clearly turns on what Aristotle thinks is perceptible, and why he thinks being subject to change entails being enmattered, and in turn perceptible. In any case, it is important that for Aristotle a great many of the elements that will be included in the real definitions at which we aim in causal inquiry are also available to observation right from the start. However, there is also a reasonably good textual basis for thinking that Aristotle takes not just efficient and final causes, but efficient and final causality to be somehow more open to perception or observation than essence and matter. In criticizing the theory of Forms and their relation to change, for example, he points to evidence from observation, as we have seen: For, if the Forms are causes, why do they not always generate continuously, but instead sometimes do and sometimes do not, since the Forms and the things participating [in them] always exist? Further, for some things we observe (theôroumen)8 that the cause is something else; for the doctor brings about health and the knower knowledge, while health itself and knowledge and the participants are [all along]; and it is the same for the other things that act in virtue of a capacity (dunamis). (GC II 9, 335b18–​24)

This claim that our observation-​based knowledge that health is caused by doctors somehow tells against Platonism is surprising, as I have noted before, insofar as the “observations” in play are hardly sophisticated. Presumably a Platonist would say that, of course, doctors bring about health in some sense, but, we Platonists argue, this must be understood along the lines suggested in the Phaedo, which gives causal primacy to Forms.9 Besides, Aristotle thinks 7 For the implication that Forms cannot explain change if they are intrinsically changeless, see Met. I 9, 992b7–​8. 8 Though the term ‘theôreô’ is closely associated in Aristotle with the ultimate end of theôria in the Nicomachean Ethics, it is commonly used in Aristotle (and elsewhere) to indicate an ordinary notion of looking, observing, beholding, or otherwise attending to something. (Indeed, it is commonly used in the Historia Animalium to indicate simply looking at a diagram or “the anatomies,” or both, as at IV 2, 525a8.) Here, context requires some such unloaded sense, since the facts adverted to can hardly be said to require close consideration or elevated contemplation. 9 Plato himself famously offers two ways of thinking about such causal relationships, one safe, one “cleverer,” which involves discovering items that are necessary bearers of the relevant Form, the way fire is related to heat (Phaedo 100c9–​105c6).

220  Causality and Causal Explanation in Aristotle that health and knowledge are formal causes as well, so they need not disagree except about whether the criticisms of transcendent Forms are justified. One might think Aristotle is simply being captious, but the claim at the end of the passage that this is similar for all things that act in virtue of a capacity (kata dunamin, 335b24) suggests that he wishes to make a general point, especially since it comes in the context of an important discussion about the number and nature of the principles needed adequately to explain generation. Aristotle’s criticism is a version, in fact, of the one Plato applies to materialist explanations in the Phaedo—​that bones, sinews, and the rest are not themselves causes, but at best necessary conditions for a cause to bring about an effect (98b6–​99b6). Aristotle refers to that very criticism immediately prior to this passage (335b10), and then claims that although these materialists are wrong, since matter as such is passive, their theory is at least more scientific (phusikôteron) than that of the Platonists. In essence, Aristotle is suggesting that Plato’s criticism of the materialists applies equally, even more so, to his own theory of causal explanation. In order for this point to have any dialectical weight, then, the observation must involve more than the shared datum that doctors, at least loosely speaking, make people healthy. Rather, Aristotle must say that what we observe includes elements that we ought to recognize as genuinely explanatory, and that this observation is sufficiently accurate to constitute evidence against a theory according to which doctors and their craft are merely involved in the process but not genuinely explanatory. Again, in Met. I 9, criticizing Plato and his school, Aristotle argues that the Platonists lose their grip on explaining “manifest” reality by appealing to transcendent forms, which are also unconnected with “what we see (horômen) to be the cause in the case of the sciences” (992a30), where here he is apparently referring to final causes:10 And in general, though we are seeking wisdom concerning the cause of things that are manifest (phanerôn), in fact we [Platonists] have let that drop (for we say nothing about the cause from which there is a principle of change [i.e., the efficient cause]), but instead, thinking we are speaking about the substance of those things, we say that there are different substances, and we 10 Ross’s translation in the Revised Oxford Translation indicates final causes explicitly, presumably since there is an implicit contrast with efficient causation, and because of the reference to mind and nature; the text, though, only has ‘because of which’ (‘di’ho’), rather than ‘for the sake of which’ (‘heneka tou’).

Causality and Epistemic Asymmetries  221 say empty things about the way the latter are the substances of the former; for “participation,” as we said earlier, is nothing. Nor, further, is this what we see (horômen) the cause to be in the sciences—​that because of which every mind and every nature acts, nor do the Forms get any grip on this cause, which we say is one of the principles, but instead, philosophy these days has become mathematics, though people say we must labor at it for the sake of other things. (Met. I 9, 992a24–​b1)

Once again, observational evidence is taken to contradict a theory, and now both efficient and final causation are presented as especially connected to manifest reality. This version of the criticism is especially interesting for our purposes, insofar as it comes in the context of a general complaint which relates to the very possibility of a science of nature: Aristotle claims that the Platonists have in fact abandoned the goal of explaining the things we observe, and that by failing to recognize efficient causes, or to provide a plausible account of motion and change, the whole investigation of nature has been destroyed (992b9). These two criticisms, then, require not just the view that efficient and final causes are elements of observable reality, which is itself significant, but that their explanatory value is also evident enough—​that our observational grasp of it is accurate enough—​to constitute a problem for any theory which attributes explanatory power to formal causes alone. To these philosophical points we may add some further indirect evidence, in that Aristotle occasionally asserts that some causal facts are evident to perception, invariably citing efficient or teleological causes. It is “evident to perception” (kata de tên aithêsin phaneron) that certain parts of the body exist for the sake of flesh (PA II 8, 653b30). We observe (horômen) that nature does nothing in vain (De Juv. 476a12), and that breath controls whether an animal is living or non-​living (De Juv. 472b27).11 We observe (horômen again), according to the Parts of Animals, that there is more than one cause of generation (I 1, 639b11). To these observables we might add the somewhat surprising fact of inter-​elemental transformation (DC III 7, 306a3–​7; GC II 4, 331a8).

11 In GA V 8, Aristotle claims that we make the general assumption that nature does nothing in vain based on “the things we see” (788b21). Note that the induction seems to rely on the thought that we observe instances of teleology—​though again, the reference is highly compressed. For the thought that final causes are more Familiar to us, cf. Bolton 1997, 118.

222  Causality and Causal Explanation in Aristotle So I think there is, on the whole, good evidence for the view that for Aristotle, the four types of cause in nature are not epistemically on a level: efficient and final causes and their causality are in general more evident and “closer to perception” than formal and material causes and their causality. This, too, may derive from a more basic thought: if we go back to the notion that the basic conceptual division among causes in general is between what pertains to a thing “in virtue of itself ” and what pertains to it “in virtue of something else,” it is unsurprising that efficient and final causes, which are generally other than what they cause, are easier to grasp than essence and matter, which pertain to a thing in virtue of what it is.12 Aristotle seems to think that in general we are better acquainted with a thing’s attributes or qualities (pathêmata)—​its extrinsic connections—​than with what it is in its own right.13 Similarly, Aristotle generally thinks that epistemic and metaphysical priorities are inversely related, so that, while efficient-​causal processes of generation are metaphysically posterior to and dependent upon the beings to which they give rise, they are also likely to be more Familiar.14 There are further differences of epistemic priority among the different types of causally explicable phenomena, however. Natural, non-​substantial changes like alteration and growth, and non-​natural changes like the generation of artifacts, are epistemically prior to natural generation, insofar as the matter and form of a generated substance are to be grasped “by analogy” with the matter and form of artifacts and the underlying subjects of natural changes in which something loses and acquires an observable property.15 We first come to understand the principles of nature by focusing on change and artifactual generation, and only then proceed to unqualified generation. Likewise, if transeunt efficient causation is on the whole more Familiar, this reasonably enough makes internal efficient causation, such as that effected by the souls of living things, less evident. Similarly, observing the final causes of processes of change, such as observing that an animal’s migration is for the sake of breeding, is easier than observing the relation between its life activities and the structures of its body, in that the second involves drawing the 12 And again, even in the special case of living substance, for which the formal and final cause seem to be one in a special sense (see § 7.5 for discussion), the diverse activities are what we confront first, which we come to understand as a theoretical unity only after investigation. 13 Against this, one might point out that on Aristotle’s telling, material causes were the first ones to be grasped; however, the early thinkers were not doing natural science, according to Aristotle, and did not formulate their material principles in ways that allowed them to draw crucial distinctions, such as that between generation and alteration. 14 See earlier, p. 139. 15 This move is explicit at Phys. I 7, 191a8–​12.

Causality and Epistemic Asymmetries  223 abstract distinction between the animal and its body, while the first requires picking out what observable activity governs the temporally prior behavior. Thus, in order to assess the full range of our epistemic progress, we need to be aware not only of general differences in Familiarity between types of cause, but among different types of causal profile.

10.2.  The Priority of Transeunt-​Causal Efficient Causality There are several reasons for thinking that, in virtue of their causal profile, origin-​ dominant transeunt-​ causal kinds such as basic “chemical” interactions are more Familiar than other important causal kinds, such as end-​dominant transformations and natural substances like living organisms. By origin-​dominant transeunt-​efficient causal kinds, I mean, again, especially the kinds of basic interaction between natural compounds such as those described in the Meteorology, which, even if they have regular endpoints, are such that their efficient causes are primary and have a unity which is independent of the regular endpoints of the transformations they produce.16 With regard to substance, Aristotle is quite clear that the very notions of potentiality and actuality involved are more difficult to grasp and more remote from ordinary experience than those involved in transeunt change. In working out his view about potentialities (dunameis) and actualities (energeiai) in Met. IX 1, he begins with the primary (malista kuriôs, 1045b36) notions applying to change—​what he refers to as potentiality to bring about changes “in another or oneself qua other” and to suffer such changes by another’s action, and it is clear from the context that “primary” here means more Familiar.17 The more esoteric notions of potentiality and actuality are those that apply to the matter and form of hylomorphic substances and their “complete” activities, and Aristotle says that these are to be grasped

16 One author/​commentator who has also claimed that efficient causes are more Familiar than the other kinds is Suárez—​indeed, it is the opening claim of his study of efficient causation, though he does not develop the point very much. His claim is just that the types of change and generation with which we are acquainted in experience cannot be brought about by the subjects of change themselves, since nothing can bring itself into existence (DM 17, introduction). I take it that the point is that since such transformations are not self-​initiated, there is an evident causal relationship to something else, whereas the being or activity of a substance is self-​contained in a way that makes grasping causal asymmetries more difficult. (If this is correct, then it is a version of my point in the previous section, that causality “in virtue of another” is easier to grasp than causality “in virtue of oneself.”) 17 IX 1, 1046a10–​13, IX 6, 1048a28–​29; though it is unclear from this whether they are Familiar in a broad sense, or simply more Familiar to a student of Aristotle’s lectures on first philosophy.

224  Causality and Causal Explanation in Aristotle by induction (epagôgêi): one ought not seek a definition of everything, but rather in this case “comprehend the analogy” with potentiality and actuality as they are understood with reference to change (1048a35–​37). Thus, transeunt efficient causation is presented as a more Familiar phenomenon by which we can come to a philosophical appreciation of the relation between matter and form for substance, considered as potentiality and actuality—​and the explicit rejection of definition in this case implies that these notions are ultimate. For end-​dominant kinds, Aristotle is also explicit that, in general, determining the final cause of a given transformation involves a pattern of inference, one which appears to be unavoidably provisional in a way that recognizing the perceptible properties involved in a change is not. As I have suggested, final causes in nature will generally be observable insofar as they are simply the endpoints of processes of change or manifest activities, but this does not mean their causality is observable as well, and not just because they are only observed when the process ends. Rather, given a process of change, it will not normally be apparent what the explanatory end-​state is, as opposed to a merely late or temporally last state. Aristotle recognizes this problem explicitly at Phys. II 2, 194a28–​32: given a complex succession of property-​changes in a given subject, we will still need some principle by which to determine which stage constitutes the end, and which is simply last. In this connection he briefly mentions a reasonable, if weak, principle of inference, stated most clearly at PA I 1, 641b23–​25: “We say this is for the sake of that in every case where there appears to be some end towards which the change proceeds, if nothing impedes it.”18 Implicit in this characterization is generality: we can only determine that a change is completed in a certain way when unimpeded if we have the opportunity to make and compare multiple observations. Final causes thus remain close to observation in one sense, but are only grasped as such by an inference to the effect that a given state or activity is the natural result of an unimpeded process of change. This generally requires also grasping that what is produced is advantageous to an organism, or somehow constitutes a thing’s function or distinctive activity, which would seem to be a further step. Thus, unlike simple generalizing induction, this is an inference, but not really from something observable to something unobservable. Rather, we infer

18 Cf. Phys. II 8, 199b15–​18.

Causality and Epistemic Asymmetries  225 on the basis of observation that a certain state or activity is “that for the sake of which” the efficient cause operates, that is, a hou heneka, rather than an intermediate state, or a state that is simply the result of the action of an independently constituted property such as heat, or something entirely indifferent to the efficient cause, such as a part of the process of decay. We grasp the end-​state of the end-​dominant process when we understand that the agent that initiated the change is constituted in such a way as to bring about that state; and it is only on this basis that we are able to give a determinate account of the properties of the agent that constitute its being an intrinsic efficient cause of that end. We thus cannot determine with scientific accuracy even the efficient cause of an end-​dominant transformation without a grasp of the end, and how it relates to the components of the process from which it results.

10.3.  Grasping Transeunt-​Causal Interactions There are good reasons for thinking that origin-​dominant transeunt-​causal kinds are not just more Familiar than other causal kinds, but epistemologically basic in several respects. I will argue for two claims: (1) Transeunt efficient-​causal interactions can be grasped as such by means of judgments that are no more sophisticated than ordinary judgments about observable properties such as shape or color. This does not amount to theoretical knowledge, but at most corresponds to the stage described in the APo. as grasping a fact or a “that” (a “hoti”), as contrasted with grasping a Why (a “dioti”). (2) Origin-​dominant efficient-​causal profiles can be scientifically understood on the basis of observational concepts and generalizing induction alone. (That is, their Why, or dioti, can be grasped in this way.) It follows that origin-​dominant transeunt natural kinds are both more Familiar than other kinds, and that they are in an important way open to analysis without going beyond the conceptual resources of ordinary observation. Thus, though we do not have much basis for adjudicating the question whether Aristotle thinks causality can be directly perceived, we do have good reason for thinking that on his view, some efficient-​causal interactions can be grasped and thoroughly understood without inference, and without

226  Causality and Causal Explanation in Aristotle deploying concepts that go beyond the range available to us from the start. They are therefore, in a certain way, just what they appear to be—​they look the same in the scientific image as they do in the manifest image. Aristotle does say quite clearly that this kind of grasp is possible, in a striking aspect of the discussion of the eclipse in APo. II 2. After distinguishing the question whether a phenomenon has a cause from the explanatory question of its cause or essence (II 1, 89b36–​90a7), and claiming that, in the idiom of the APo., this amounts to seeking whether there is a middle term and what that middle term is, he then argues (II 2) that for the range of things that have intrinsic causes (middle terms) the answers to the questions of what something is and why it is are the same (90a14–​23).19 He then states that this is supported by cases in which the middle term is perceptible (90a24–​25): for us here on Earth, when we see a lunar eclipse, we do not see what causes it, and so we must first determine whether it has an intrinsic cause. But, he says, if we were on the moon, we would simultaneously perceive both that the eclipse has an intrinsic cause and what its cause is, which is the same as seeing what an eclipse is (90a26–​27). He even goes so far as to make it seem, in contrast to his usual distinctions, that perception is here sufficient for grasping the universal (i.e., the universal intrinsic cause which constitutes the essence): “For from perceiving, it would also come about that we know the universal. For perception grasps that [the Earth] is now screening (for it is clear that [the Moon] is now eclipsed); and out of this the universal would come about” (II 2, 90a28–​30). Most likely Aristotle is describing the process in a compressed way, and some “noetic” capacity would need to come into play to accomplish this—​he is certainly not contradicting the point about which he is perfectly clear in the same chapter, that perception does not by itself grasp a universal cause.20 Nevertheless, he points out that in this case we would seek “neither if it is nor Why” (“out’ ei ginetai oute dia ti,” 90a27), and it is striking the extent to which he seems to think perception is a sufficient condition for our coming to grasp the universal essence, so that we answer both questions without inquiry. More important, though, is that this passage clearly does contain a philosophical commitment to the idea that sometimes a causal relationship, including the essential nature of the relationship involved, is fully open to view and can somehow be grasped on the strength of our normal observational

19 Described earlier in § 9.4. 20 See § 9.3.

Causality and Epistemic Asymmetries  227 powers of a particular instance. That is, it is one thing to deny that we could grasp universals with perception—​something Aristotle clearly does—​and quite another to deny that we can perceive particular causal relationships as such. Aristotle is asserting in this passage that we can do the latter, and in propitious circumstances we do so in a way that leaves very little for us to do in order to grasp the universal cause, other than to universalize what we perceive in the particular instance.21 As I have mentioned, one of the drawbacks of looking at the APo. for an understanding of Aristotle’s views about causal explanation in natural science in general is that so many key concepts of natural science are simply not present on the surface, nor is it clear whether they lie beneath it or how far. Nevertheless, I think the general commitment expressed in this passage is sustained in the more properly natural-​scientific works, especially by his more detailed accounts of the nature of origin-​dependent natural kinds. (It is thus no accident that the example he chooses in the APo. II 1–​2 passages, the eclipse, is also an origin-​dependent kind.) These kinds are, as we will see, an important foothold for reaching more sophisticated types of natural kind, and so even if a full scientific understanding of nature requires going well beyond the resources available to ordinary perception, we begin from a state in which there is no conceptual gap that needs to be overcome between the phenomena we observe and the causes that explain them. I have argued in Part II that on Aristotle’s view a basic interaction involves just the agent (as such) and the changeable patient (as such), which jointly comprise what we might consider a composite potentiality; they have in turn a non-​composite actuality, namely the change which occurs in the patient when the right circumstances are met and nothing impedes it. We might call this a “two-​factor” view of transeunt-​causal interactions, in contrast with a “three-​factor” account, more standard in recent work, which analyzes such

21 This is, at any rate, a promising way to reconcile the claim of I 31 that even on the moon we would not perceive the cause with that of II 2, that on the moon we would not need to seek the cause, perception being somehow sufficient for bringing it about that we grasp the universal cause. But reconciling the passages is anyway difficult: in I 31 he says it is necessary to “hunt for” the universal (88a3), while at the end of the same chapter and in II 2 says there will be no need to “seek” it (88a13, 90a26). Barnes 1994 thinks that Aristotle is assuming multiple observations are needed, and that we do not need to “cast around” for a middle term; but there is no basis for this in the passage, and it removes the contrast Aristotle has drawn between these cases and ordinary ones. As Barnes points out, all universal knowledge ultimately derives from perception, so in a weak sense all middle terms are perceptible (206)—​so this undermines Aristotle’s aim of showing that there is sometimes a further step required, namely establishing whether something has an intrinsic cause at all.

228  Causality and Causal Explanation in Aristotle interactions in terms of a special (and universal) relationship obtaining between non-​causal relata such as events or states of affairs. This two-​factor metaphysical analysis of causal interactions has important consequences for the cognitive task of coming to grasp both that a causal phenomenon is present and for determining its real definition, that is, for knowing a fact and knowing the Why. Here, too, it is helpful to contrast the view with a rough account of how these two stages work on a three-​factor view. On that approach, to grasp a cause in a singular interaction, we need to observe the cause-​event and the effect-​event separately, and, retaining at least the earlier one (or probably both) in memory, supply a further relation between them by way of some distinctive, non-​perceptual act—​whether inference, habit, schema application, or whatever, which would seem to deploy non-​observational concepts. We see A, then we see B, then we judge that A caused B. However quickly we do this, the steps are distinct, and it seems inevitable that they be successive as well. They seem, that is, to be inferential, which is indeed how Hume can raise the problem of induction, by demanding to know the rational basis of this inference. The second step, grasping a general causal pattern, would seem to require grasping that there is a law-​like relationship (counterfactual or otherwise) between the two events, considered as types—​classically as a result of observing regularities.22 By contrast, on Aristotle’s view, the first step in grasping a causal relationship of this sort is to move from a pre-​theoretical account of the phenomenon—​that is, one that only indicates a subject undergoing a change in the category of either quantity, quality, or place—​to a grasp of that very same change as something essentially causal—​as a change in which an agent is an intrinsic cause of a change in a patient. (The prior changes leading up to the change, again, are the satisfaction of antecedent conditions rather than causes.) This is not a negligible step, since it involves ruling out both that the change is co-​incidental and that it is an immanent or “self-​qua-​self ” type of change, like animal movement or waking up from sleep. Nevertheless, it is importantly different, insofar as it amounts to a change in how we grasp a single phenomenon that Aristotle considers to be a genuine unity, rather than an inference that posits a relationship between two distinct phenomena. How do we accomplish this? 22 Hence the emphasis, across many different types of account, on specifying the nature of natural laws or distinguishing “law-​like” regularities from merely co-​incidental regularities. Of course, there are many refinements and possibilities, and some do argue that cause and effect may be considered simultaneous, e.g., Huemer and Kovitz 2003.

Causality and Epistemic Asymmetries  229 Now, Aristotle’s account of the contents of perception (aisthêsis) is notoriously thin, as I have noted, but there is enough textual evidence to support the view that the elements of these causal interactions are open to ordinary observation. As we have seen, Aristotle tends to think of agents as bearers of properties by which they are capable of bringing about certain transeunt changes, and that in cases of simple interactions those properties are perceptible in their own right.23 We also observe changing patients in ordinary perception—​indeed, in the De Anima’s brief account of the intrinsic (kath’hauto) objects of perception, change (kinêsis) and rest (êremia) are included under what he calls common perceptibles (DA II 6, 418a17–​19), alongside number (arithmos), figure (schêma), and magnitude (megethos). Though these are not the proper objects of any individual sense modality, he is clear that they are intrinsic objects of perception, unlike his third category of perceptible, which he refers to as co-​incidental. In fact, he claims that change is the primary common perceptible (III 1, 425a16–​18). Of course, what Aristotle lists as perceptibles are generic terms, but he does not think that we observe something like shape or color as such, and then draw inferences as to what kind of shape it is. Rather, we perceive blues, reds, triangles, and squares, out of which we develop a more abstract category of color or shape. If this view applies to other perceptibles, then we would similarly perceive determinate sorts of change and eventually work our way up to a general notion. In the Categories, Aristotle treats the transeunt-​causal categories of acting upon (to poiein) and being acted upon (to paschein) as basic categories alongside substance, quality, and the rest: examples include cutting and being cut, burning and being burnt (Cat. 4, 2a3–​4), heating and being heated, cooling and being cooled, and being pleased or being pained (Cat. 9, 11b2–​4). He thus counts determinate forms of what I have called intrinsically causal phenomena as being among the most basic types of thing there are, and indeed, as we have also seen, he sometimes treats them together as a single category of change (kinêsis, e.g., at Met. VII 4, 1029b24–​25). Actions and passions like these would thus be the determinate correlates of other perceptibles like colors and shapes, being determinate types of change, which is, again, an intrinsic object of perception. We might therefore infer that for Aristotle, observing an instance of cutting or heating as such 23 See especially Mete. IV 8, 384b34–​385a6, translated and discussed in more detail in the next section.

230  Causality and Causal Explanation in Aristotle need be no more sophisticated than seeing that something is blue or round, or that someone is in the Lyceum, lying down, or wearing armor. So just as common perceptibles like shape, number, and magnitude are elements in basic categories of quantity and quality, but we perceive determinate types rather than shape or number as such, so also we observe transeunt-​causal changes of determinate types. And because transeunt changes are not simply property-​changes with external causes, since the manner in which they are caused is essential to them, making a judgment about a thing’s efficient cause is a matter of grasping what determinate kind of a change it is. Thus, in many cases, the cognitive task of the first-​stage causal knowledge for basic transeunt interactions is simply to apply the right predicate of action and passion—​to recognize the change one observes as a determinate kind of action and passion. Perhaps Aristotle would say that, though we do not observe shapes as such, nor do we observe isosceles triangles as such until we have been trained to make such discernments. We begin, instead, with predicates of intermediate generality. In the same way, perhaps what we initially observe is something like motion in place, change in temperature, change in bulk, and so on. So, from the perspective of judgment, observing any change will involve applying a specific predicate for the type of transeunt change it is—​not just moving in place or changing in quality but pushing, pulling, cutting, burning, and so on—​but we must acquire the ability to do so by experience, just as we do for other predicates, and we will often rely on more general ones until we do. Thus, even if an extra step is required, in order to grasp a phenomenon as a causal interaction, for Aristotle, the cognitive task is not to infer a relationship between two observables, as on the three-​component view, but rather to apply the right transeunt-​causal predicates (i.e., predicates of action and passion) to an observable change, where this may require developing finer-​grained distinctions over time. It is not clear, as noted earlier, whether Aristotle thinks of the intrinsic objects of perception in terms of what we would call the content of perceptual states narrowly conceived, as opposed, for example, to perceptual judgments. That is, it is not clear whether or to what extent he thinks perception in general, or perhaps human perception in particular, involves content that goes beyond the intrinsic perceptibles to which the perceiver is naturally sensitive, nor at what point more sophisticated forms of cognition must enter the picture.24 Nevertheless, pursuing the similarity with other forms 24 Again, see Gasser-​Wingate 2021, ch. 4. A key issue he does not settle is whether Aristotle, in discussing perception, is concerned primarily with states that are entirely the work of the perceptual

Causality and Epistemic Asymmetries  231 of judgment, we can argue at least for a parity claim: however one comes to distinguish triangles and to apply predicates like ‘triangle’ or ‘isosceles’ to observable objects, one does the same for the causal predicates of action and passion in observing basic interactions. My suggestion, then, is that if we were to ask Aristotle what account he would give of our ability to grasp causes in particular instances, he would at least begin to respond by claiming that we perceive action and passion, the most Familiar kind of causal phenomena, in the same way we perceive houses, people, fire, and horses, and, more generally, substances, artifacts, elements, and so on.25 That is, the representational content of ordinary experience includes some forms of causality in whatever way it includes other familiar types of content. He clearly thinks we do perceive such things as part of our ordinary activities as rational beings endowed with perception, without making inferences or positing hidden substrates. Ordinary perception, however he conceives it, is not limited in its content to the intrinsic special (idion) and common perceptibles.26 He also assigns to the perceptual capacity itself certain sophisticated kinds of cognitive function, including ones that seem directly to counter the way Plato treats perception in the Theaetetus. He places number among the common intrinsic (kath’hauto) perceptibles, and he claims that our perceptual faculties are responsible for distinguishing perceptible properties from one another both within and across sensory modalities.27 Aristotle’s treatment strongly suggests that all such perception or perceptual judgment is non-​inferential: we do not see a change and infer

faculty, or rather states whose content includes only predicates that apply to perceptible individuals as such—​hence do not include universals of the type that are only available to the intellectual faculty. It may be that what he says is indeterminate between these options. I agree, however, with the basic point (p. 125) that it does not follow from intrinsic perceptibles being psychologically basic that they are epistemically basic as well. 25 Very likely, as others have noted, the same account should also be extended to include “value” terms, though it might be objected that we should not even think of this as an extension strictly speaking. That is, one might argue that evaluative properties do not bear a special burden in order to be admitted among the class of observables in the rich sense—​the idea that they do bear such a burden is a product of the stance that anything which does not bear a close enough connection to the primary perceptible qualities of material objects as such must have its existence defended, on pain of naturalist skepticism. 26 On the extent of perceptual contents, see Barnes 1994, who connects the universals in APo. II 19 to co-​incidental objects of perception (266), as well as Johansen 2012, ch. 9, and Gasser-​Wingate 2021, 106. A particularly prominent example of robust perceptual content, where that capacity and its activity are clearly being kept distinct from those of imagination and thought is at DA III 7, 431b5: one perceives “that the beacon is fire.” 27 See DA III 1, 425a13–​b4; III 2, 426b9–​427a16; as well as Burnyeat 1976; Johansen 2012, ch. 11.

232  Causality and Causal Explanation in Aristotle that it is a pushing of B by A, any more than we see a patch of color and infer that it belongs to a horse. This view in fact fits nicely with Aristotle’s brief remarks about induction in Met. I 1 that we saw earlier (§ 9.3): And craft arises whenever out of many considerations [ennoêmatôn] of experience a single universal grasp [hupolêpsis] comes to be concerning things of the same sort. For, to have a grasp [hupolêpsis] that this benefitted Callias when he was sick with this illness, and also Socrates, and thus individually for many people, is experience; but to have [a grasp] that it benefitted everyone of this sort, marked off by virtue of one form, suffering this illness—​ for example phlegmatic people or bilious people [or those] suffering from bilious fever—​belongs to craft. (981a5–​12)

We can see now that the process of induction being described here is after all the same sort of generalizing induction described at the end of APo. II 19: just as we arrive at a general notion of human by wide experience with many individuals, and a grasp of animal by wide experience of different species, so we can arrive at a general grasp of curing fever by wide experience of its instances, and then to a more universal grasp of what kind of action curing fever might turn out to be. The difference is that in the Met. I passage, the experience from which we generalize involves causal data right from the start, since the example is a generalization of a kind of transeunt action, rather than the species example he seems to be using in APo. II 19.28 Thus, Aristotle embraces the Causal Observationalist position as I have described it to the extent that a great deal of ordinary observation is unproblematically causal in its content. Moreover, since grasping that a change is an action of an agent on a patient already includes grasping that it is not a co-​incidental result of some other process, this type of observation already includes a grasp that an observed phenomenon has intrinsic (kath’hauto) causes. In many such cases we are simply trained to recognize them in the same way we are trained to recognize other types of thing or property. In the face of a new phenomenon, grasping that a given change is a kind of action 28 Commentators tend to state or assume that causal concepts only enter the picture after experience, at the noetic stage of cognitive progress, perhaps by assimilating the Met. I story to the APo. II 19 story, and/​or perhaps by implicitly accepting a Humean picture (see, e.g., Gasser-​Wingate 2021, xiii, 45). But by itself the Met. I picture suggests the contrary, and this aspect is one of the differences that we might expect to result from its focus on grasping causes rather than first principles of demonstration.

Causality and Epistemic Asymmetries  233 and passion is in essence the same, though it requires either recognizing that the change is of a determinate kind one already knows (e.g., recognizing that an eclipse is a kind of blocking of light, with which one is already familiar), or grasping that it is of a more general kind which must be further refined (e.g., recognizing that metal is being made softer and more flexible by application of heat, before one has distinguished annealing from melting or other forms of softening-​by-​heat). Both the metaphysical account of basic transeunt interactions and Aristotle’s general commitments regarding the nature of perceptual judgment therefore suggest that for the first stage of causal understanding, for these natural kinds, the resources of ordinary perceptual judgment are sufficient.

10.4.  Understanding Origin-​Dominant Causal Profiles The next point to articulate is what it takes to move from this pre-​theoretical grasp of a phenomenon as a causal kind of change to a grasp of the intrinsic causes that constitute its real definition, along the lines of the schema suggested at the end of Phys. III 3 and discussed earlier. This requires, as we have seen, determining exactly what properties of the agent and the changing subject constitute the grounds of their mutual ability to act and be acted upon by one another in a transeunt change. Now, since Aristotle thinks that the properties involved in basic “chemical” interactions are restricted to intrinsically perceptible properties such as degrees of heat and moisture, hardness and softness, he has reason to think that the precise properties that constitute the real definitions of such interactions are again directly available to perception. He makes the point explicitly at Mete. IV 8, 384b24–​385a8: From these things it is clear that bodies are formed by hot and cold, and that the latter do their work by thickening and solidifying. And because of their being fashioned by these things, there is heat in all of them, and in some there is also cold to the extent they are lacking. Thus, since these qualities are present in virtue of acting, while moist and dry are present in virtue of being affected, the compound bodies have a share of all of them. So the uniform bodies are formed out of water and earth, both in plants and in animals, as well as the metals, such as gold and silver and whatever other things are of this sort—​from these and from the exhalation enclosed

234  Causality and Causal Explanation in Aristotle in each thing, as was described elsewhere. And all of these differ from one another (a) in relation to the special perceptual capacities, i.e. by virtue of being capable of acting on something in some way; for things are white and fragrant and resonant and sweet and hot and cold by virtue of being capable of acting on the perceptual capacity in some way, and (b) in relation to their other peculiar qualities—​those that are spoken of in terms of being affected. I mean, for example, being able to be melted or solidified or bent, and whatever else is of this sort; for all of these sorts of quality are passive, just like moist and dry.29

Thus, the properties that both distinguish these compound bodies from one another and which endow them with their various powers are intrinsically (kath’hauto) perceptible in the primary sense—​they are indexed to our individual sense modalities. If, as I have argued earlier, Aristotle gives a series of real definitions in Mete. IV of “the things spoken of in accordance with capacity and incapacity” (8, 385a10–​12), then it is noteworthy that his discussion of these causal kinds gives every impression of being complete, despite the fact that it consists mainly in stating what he takes to be the relevant qualities of agent and patient. As also noted earlier, he stops at various points to say that he has said both what and why these kinds of change are, and his evidence consists of statements about the perceptible qualities (hot, cold, moist, dry, hard, soft) of the relevant bodies and their associated compositional properties (watery, earthy, porous, etc.).30 This way of proceeding contrasts rather starkly with his discussions of other topics like inter-​elemental generation in On Generation and Corruption, celestial phenomena in the De Caelo, more remote meteorological phenomena in Mete. I–​III, the teleological causes of the parts of animal bodies in the Parts of Animals, and animal generation in the Generation of Animals. These works also take their tasks to be giving precise accounts, especially causal accounts, of what things are and how they occur, but they involve much more appeal to alternative views, puzzles,

29 What I have labeled ‘(a)’ contains the claim indexing the nature of these bodies to perceptible properties; (b) is different but is evidently posterior to (a), especially insofar as it indicates passive properties—​susceptibilities to change along the same ranges of properties already indicated. 30 See Mete. IV 3, 380a12ff., and especially IV 8, 384b34ff. When there are inferences, these are mainly straightforward analogies that transfer directly observable perceptible qualities to cases where direct observation is not possible for contingent reasons (e.g., size): for example, it is inferred that oil must contain air because it is not solidified by either cold or heat but is rather (apparently) thickened by the former and thickened and whitened by the latter (383b20–​384a2).

Causality and Epistemic Asymmetries  235 inference to the best explanation, and in general appeal to arguments based on considerations other than what is directly open to observation.31 If I am correct, this difference is no accident: the constituents of the scientific definitions for these basic interactions are directly observable, since the relevant properties are indexed to our senses, such that, just as in the case of witnessing the eclipse from the moon, it suffices to observe the action under favorable conditions to recognize the causes involved. Whatever cognitive powers beyond basic perception are involved in this recognition, they appear to be of the sort that allows us to recognize a basic universal in experience, rather than any kind of capacity for inferring or explaining what we observe on the basis of something unobserved, or of connecting two temporally remote observables such as animal seed and the organs and body that develop as a result of its action. Thus, transeunt-​causal change is more Familiar than other types of causality, and origin-​dominant causal profiles such as basic chemical interactions are Familiar in a way that allows us to grasp both that they are causal phenomena (their pre-​theoretical accounts as types of action and passion) but also their causal definitions, using the conceptual resources of ordinary perceptual observation, just as the eclipse example in APo. II 2 suggests we can. Aristotle therefore extends the Observationalist position beyond the stage of simply grasping a phenomenon as causal in ordinary observation: our observational capacities and non-​inferential, generalizing induction are sufficient for a scientific understanding of certain causal kinds.

10.5.  Summary Aristotle has a rich picture of the manifest image, which includes both types of primary causes that anchor different causal profiles, that is, efficient and final causes. Our observational capacities are also robust enough to capture their explanatory value, such that observational evidence can tell against 31 Indeed, GA II 2 contains reasoning to a conclusion about the material composition of sperma that is quite close to the reasoning about oil in Mete. IV 7 just cited: sperma is puzzling insofar as, if it is watery, it should not be thicker when hot, but if it is earthy, it should not liquefy when cool; the fact that oil behaves similarly and contains air is part of the basis of an inference to the conclusion that sperma is a mix of water and pneuma (736a1). Even though the reasoning here is not teleological, it is more complicated, and indeed uses the simpler kind of interaction detailed in the Mete. as the basis of a more tentative analogy. The reasoning to teleological conclusions in PA II–​IV contrasts even more sharply.

236  Causality and Causal Explanation in Aristotle a theory (such as Plato’s) that assigns to them the status of mere necessary conditions. That is, there are good reasons for thinking that Aristotle takes both efficient and final causes to be “more knowable to us” (more Familiar), while formal and material causes are “more knowable simpliciter” (more Intelligible). There are further epistemic asymmetries between different types of causal profile. Notably, changes with origin-​dominant three-​component profiles, such as basic chemical interactions, are more Familiar than many other paradigmatic natural changes, both insofar as they involve a more accessible notion of potentiality (dunamis) and because we require a more complex, inferential pattern of thought to pick out the causes for changes with end-​ dominant profiles. Further, at least some transeunt efficient-​ causal interactions can be grasped as such by means of ordinary perceptual judgments (grasping the “fact”), and they can be scientifically understood by means of observational concepts and generalizing induction (grasping the “Why”). Aristotle thus thinks that some causal relationships are fully open to view, in that there is no conceptual gap or inferential work required to move from the explanandum to the explanans. Rather, the first cognitive task is to apply the right causal predicate (i.e., an agential or passive predicate), and these are among the resources of ordinary observation. Further, for basic kinds of change such as simple “chemical” interactions, we are capable of grasping both that a change is of a certain essentially causal type, and what the definition of that type is—​completing the second task—​using ordinary observation and induction. Induction does not, then, at least in these cases, move from a cause-​free domain of observation to a causally loaded domain of thought; rather, some generalizing induction begins from observations that are causal right from the start. To put the point more broadly, if there is ultimately a theoretical question about how causal properties or relations supervene upon more basic non-​ causal entities, it is not a problem that arises from a correct account of the nature of experience. A correct account of experience, on Aristotle’s view, implies the contrary: if experience is to be trusted, causality is as basic as anything. A theoretical problem only arises by way of a claim that experience is misleading on this score, and that in fact there is a set of basic non-​causal entities, such that any causal relationship or property would be less basic than they are, and in such a way that its presence in experience needs to be explained differently than the presence of other basic elements.

11 The Non-​Secret Connexion 11.1.  Is Some Causality Just as It Appears? From what I have argued so far, we can say that Aristotle thinks that causal understanding involves different types of cognitive capacity for different types of causal relationship and causal profile, and that some efficient-​causal kinds are epistemically privileged insofar as we can grasp both that they are causal kinds and their real (causal) definitions using only the conceptual resources of ordinary observation and non-​inferential induction. These types of causal kind are therefore just as they appear, and so our starting point for grasping causes does not involve a move from a stage that lacks causal content to one that introduces causal concepts “from outside.” For at least this type of causality, there is no gap between appearance—​or at least what is available to careful observation—​and reality. It is reasonable to object at this point that the view has a serious weakness: the fact that these definitions are thoroughly knowable in this way looks to be an accident of the fact that Aristotle thinks both that hot, cold, moist, and dry are fundamental properties, and that they are essentially indexed to perceptual capacities. If he knew that they were not fundamental properties, he would not be able to maintain that we wholly understand these interactions. This is an important worry: it is no accident that distinctions between primary and secondary qualities underlie some of the most influential critiques of Scholastic metaphysics. At the same time, there are several qualifications that need to be made, and there are a variety of options open to Aristotle. First, we must clarify that Aristotle does not think our access to these basic properties is as immediate as it might sound—​he has a long discussion in PA II 2, for example, of the ambiguity of ‘hot’ (648a19–​649b8). The upshot of it is that there are a variety of properties which present themselves to us as being hot, which are difficult to separate. Our direct access to heat consists in the fact that its basic form is among the appearances of heat to which we are subject, not that we have, for instance, clear and distinct or self-​certifying impressions of heat. Second, Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0012

238  Causality and Causal Explanation in Aristotle while I have described these interactions as basic, they are not, for Aristotle, the most basic type of interaction among the physical elements. Those would be the inter-​elemental transformations and the various ways in which the elements move or impede each other’s motion. Since these are intermediate-​ level interactions among complex composites, then, Aristotle is not maintaining that we have direct access to the most basic kinds of interaction in nature—​and his accounts of those other types of elemental action are clearly more tentative. From this perspective the fact that these interactions are framed in terms of what he also takes to be basic qualities is irrelevant to the point I wish to make. Aristotle does not need to maintain that all elemental interactions are fully open to observational knowledge, or even that the fundamental ones must be. He only needs to maintain that some types are, and that they are just what they appear to be—​that some of the properties that are manifest to us, and manifest to us as constituting causal powers, really do so. It would take a direct kind of reductionist argument that no such interactions are caused by the properties that are manifest to us, of the sort that Aristotle has already rejected for independent explanatory reasons, to counter it. (This includes his general view that things which are always just what they are cannot, by themselves, account for change. See §§ 2.1–​2.) In any case, Aristotle would have plenty of allies in maintaining that a property need not be fundamental to have causal power. This view allows Aristotle to give a more nuanced response to the explanatory reductionist who claims that only basic entities can be causes strictly speaking, and that these are not given to ordinary observation. Aristotle’s response need not be that all causality or even that causality for ontologically basic entities or properties is evident to perception in order to provide a solid empirical foundation for natural science that meets the criteria against which he judges his predecessors, only that some causality is just as it appears. This is sufficient for claiming that induction or inference to more sophisticated causal kinds and natures is not based from the outset on mere belief, nor does our initial grasp of genuine causality depend on the sort of hypothetical reasoning deployed by Socrates in the Phaedo either.1 Even though this is a relatively modest claim, I think it is important for Aristotle’s position that some causality should be like this. If there is always a gap between what appears to be a causal relation and what, if anything, is 1 See Phaedo 100a2–​b9; cf. 101d1–​e3.

The Non-Secret Connexion  239 really doing the causal work, then the reductionist is entitled to claim that for all we know, all of our claims about causality may be appealing to the wrong sorts of thing as explanantia, and so all of our claims about causality should be treated as hypothetical. If that is how they must be treated, then Aristotelianism loses a key advantage that he wishes to claim over the various kinds of materialist and Platonist reductionisms.2 Still, even granting Aristotle’s claims about basic interactions as I have framed them, a more sophisticated reductionist (or indeed a Cartesian) might argue that genuine causality in nature involves material kinds and properties much further removed from ordinary experience than Aristotle realizes, and so even if we allow that ordinary observation suffices for some types of observable phenomena, these are so distant from the targets of genuine scientific understanding that we should not count them for much. The efficient causality that applies to genuinely basic material kinds still, on this line of argument, involves a conceptual leap that cannot simply extend the notions available to ordinary experience, and so our grasp of whatever causal phenomena can be framed in terms of properties available to perception is not a sufficiently accurate point of entry. This is a fair objection to raise: just as we saw in discussing modern “neo-​mechanist” views, it is a substantive and open question how far this type of analysis can extend, whether it needs grounding in a radically different kind of relationship, and whether we should even describe the most basic kinds of natural phenomena using the same causal concepts that apply to less basic phenomena that are nonetheless objects of scientific understanding. Just as in that context, I take it to be a virtue of this interpretation if it means Aristotle is open to the kind of objections that are raised against these substantive modern theories of causality.

2 In a way, then, I am extending to Aristotelian causality a claim that has often been made about other key philosophical concepts, including ethical and ontological ones, namely that Aristotle rejects a more recent dichotomy between what is given in experience and what is contributed by distinctively intellectual capacities, such that the concepts of most interest to philosophers, for example, are sharply on the latter side. Aristotle is standardly interpreted, for example, as thinking that a great deal of ethical knowledge is acquired through experience and acculturation, which indeed forms a necessary basis for coming to have a philosophical understanding of happiness and virtue. Similarly, I suggest, a great deal of causal knowledge is acquired and available to ordinary and careful observation, which is in turn a basis for more developed scientific and philosophical understanding of causality in nature.

240  Causality and Causal Explanation in Aristotle

11.2.  The Special Importance and Epistemic Status of Crafts The importance for Aristotle of establishing that at least some causality is as it appears to us is another reason for clarifying the role of craft production in Aristotle’s theory. As I argued earlier (§ 6.1), craft is not just a useful analogy for causality in nature, nor is it a theoretical model in the sense that the meanings of its terms are fixed by the model and then extended to nature; rather, it is a “model” of causality simply insofar as it is an accessible example of causality without qualification.3 Because craft is a human enterprise, however, and craft expertise is something we know first-​hand—​or that we can at least connect to our first-​hand understanding of ourselves as agents—​it has the additional virtue of being fully intelligible to us in ways that advance our understanding of nature beyond simply furnishing us with a good starting point.4 One might argue, after all, that what I have described as a foothold in experience for a scientific understanding of causality is too weak for Aristotle’s purposes. In particular, we might note that Aristotle has not given us good grounds for thinking that we can grasp teleological causation, since it is not an essential part of understanding origin-​dominant kinds—​at least not in anything like the sophisticated forms Aristotle describes for end-​dominant kinds. After all, Aristotle thinks that efficient-​ causal potentialities for bringing about end-​dominant kinds are metaphysically posterior to what they are potentialities for, and so they depend on our grasp of a notion of goodness or function.5 Here, too, then, one might argue that the most important causal concepts are still hypothetical, introduced by a distinctively intellectual capacity, rather than an extension of experiential concepts. Probably the most important passage in which Aristotle affirms the epistemological value of craft expertise is a well-​known passage from Phys. II 8, which is part of Aristotle’s response to reductionists like Empedocles who, 3 A number of commentators have noted the importance of craft-​causality and craft products as models for special types of causality or entity in nature, but without clarifying the difference between such analogies and craft as simply a clear example of efficient causality. See, e.g., Sedley 2007; Witt 2015; and Fernandez and Mittelmann 2017. See Graham 1987 for the model view. See Broadie 1990 for worries about the “craft analogy” for nature and teleological causality. 4 Sedley 2007 and Fernandez and Mittelmann 2017 point out that craft is helpful in understanding nature because it is Familiar in the Aristotelian sense. 5 It is also important to note that, with respect to Platonists, the fact that Aristotelian forms are supposed to be enmattered does not by itself guarantee that they are more knowable than separate Forms, if only because the claim is vague thus stated.

The Non-Secret Connexion  241 he thinks, might contest whether nature is a cause that acts for the sake of something—​that is, who would deny, in my terms, that various types of change that occur in natural beings exhibit end-​dominant causal profiles. The passage has received somewhat less attention than the “rainfall” argument (198b16–​199a8)—​which argues that natural things must occur for the sake of something because they occur regularly, and so not co-​incidentally—​ partly because it is clearer and less controversial, but also because it seems to be a weaker point, even less likely to persuade a skeptic.6 I think the passage has more weight to it than it may appear, but it is especially interesting for what it implies about how we come to grasp final causes in nature, on the assumption that there are such: Further, in those things for which there is a goal, what comes earlier, and the sequence, is done for the sake of this. So howsoever it is made, this is the way it is by nature, and howsoever it is by nature, so each thing is made, unless something impedes. But it is made for the sake of something; therefore it is by nature for the sake of something. For example, if a house were among the things coming to be by nature, it would come to be in the very way that it does in fact by craft; and if the things that are by nature were not only by nature but could also come to be by craft, they would come to be in the same way as they do by nature. Therefore the one thing is for the sake of another. And in general craft completes some of the things that nature is unable to work up, and imitates others. So if the things in accordance with craft are for the sake of something, it is clear that the things in accordance with nature are as well; for the posterior and prior things stand similarly in relation to one another in those things that are in accordance with craft and those in accordance with nature. And it is especially clear among the other animals, which act neither by craft, nor as a result of inquiring or deliberating; which is why some are puzzled whether spiders and ants and these sorts of animals work by thought or something else. And progressing bit by bit in this way, even in plants the advantageous things evidently come to be in relation to the goal, for example the leaves for the sake of a protection over the fruit. So that if the swallow makes its nest and the spider its web both by nature and for the sake of something, and plants make leaves for the sake of the fruit and make 6 See Charlton 1992, 123–​26. For doubts about the value and importance of these arguments, see Cooper 1982.

242  Causality and Causal Explanation in Aristotle the roots go not up but rather down for the sake of nourishment, it is clear that there is this sort of cause in the things that come to be and are by nature. And since nature is twofold, being in one way matter and in the other shape, and the latter is the end, while the other things are for the sake of the end, this [sc. the shape] would be the cause, in the sense of that for the sake of which. (199a8–​32)

The argument seems initially unpromising, since it lays down at the start that things are “made” and come to be by nature (pephuke) in the same way, which is precisely what the materialist-​reductionist rejects—​nor does it seem as though the passage really aims to persuade someone who denies the very possibility of natural teleology. Further, the claim that craft imitates nature (a16) makes it seem as though the two kinds of causal production are not in fact the same. However, the passage nonetheless has persuasive force if one’s position is that natural teleology is possible in principle, but whether nature really does act for the sake of something is a contingent thesis that needs support.7 For here Aristotle argues that there is no sharp distinction between making things in the way distinctive of craft and the way things are produced in nature: they would occur in the same way if what were artificial were capable of being naturally produced, or vice versa, and sometimes craft completes the work of nature. And, as Aristotle notes in the Mete., the sub-​processes involved, such as heating, cooling, concoction, and so forth, are often exactly the same.8 These latter claims in particular suggest that we should not again interpret “imitation” as implying that craft involves causality in any kind of secondary or diminished sense—​craft processes are usually built up out of natural processes and can, in turn, bring natural processes to completion. This combination of observation and supposition is justified by a claim that the same types of priority relations are to be observed in both craft and nature: materials are prepared so that they come to be capable of undergoing certain types of transformation and performing certain functions, and then further changes are initiated to bring the materials into a new state or to constitute a new thing with its own distinctive capabilities. Further, there are 7 And this, arguably, is the view being targeted, rather than someone who denies the very possibility of teleological causes. Cf. Meyer 1992, §§ 3–​5. 8 Mete. IV 3, 381b6. Aristotle elsewhere gives medicine as an example of a craft that brings about the same result that sometimes occurs naturally (Met. VII 7, 1032b21–​26). For the claim that craft imitates nature, see also Phys. II 2, 194a21; Protrept. Fragment 13 ln. 2, Fragment 14 ln. 1.

The Non-Secret Connexion  243 clear examples of natural but non-​intelligent “making,” such as making webs and nests, which further smooths out the transition between intelligent craft and end-​directed natures. Thus, if one allows that natural teleology is in principle possible, and that craft constitutes a well-​understood example of genuine teleological explanation given in experience—​connected to our basic understanding of our own ability to act for the sake of producing an end—​there is good evidence for applying teleological explanations to nature, not by a hypothesis to the effect that natural things resemble the works of craft in the way they come about, but rather by an inference to the effect that the causal relations between their ends and their coming to be are the same in kind. It is also important to see that craft-​knowledge illuminates two aspects of causality in nature: teleological relationships in the standard sense, according to which some property or entity is or comes to be for the sake of something else, which includes static relationships between a thing’s matter and its function, but also the notion of an end-​dominant efficient cause, whose unity derives from what it promotes. This reading helps us see some of the agreement and disagreement between Plato and Aristotle on our ability to understand nature. Both evidently think that craft illuminates nature, but they are often said to contrast with one another in the type of illumination provided: Plato evidently (and as Aristotle reads him) thinks it does so because the natural world is an artifact (and a god), whereas for Aristotle craft processes are analogous to natural ones.9 But while Aristotle does, of course, deny that natural things are artifacts, craft is not illuminating because of an analogy, but rather because the causal structure of natural kinds and the products of craft are just the same, and crafts are fully intelligible to us. This difference also yields a difference in the type of reasoning by which we arrive at an understanding of natural teleology. For Plato, we introduce the claim that natural things have teleological explanations by a hypothesis; for Aristotle it is an inference, based on a contingent but, he thinks, empirically grounded premise that the causal relationships we find in natural things are of the same types as we find in crafts. This view of craft also distinguishes Aristotle’s from other philosophical views about our experiential access to causality and causal concepts. Philosophers who have thought that we have direct experience of at least 9 See Burnyeat 2005, esp. 144–​45; Johansen 2004, ch. 4.

244  Causality and Causal Explanation in Aristotle some causality have tended to cite either a kind of inner access, by way of our bodily sense of pressure or our sense of agency, or, like Anscombe, have maintained against Hume that ordinary observation or even perception has causal content, at least no less than it has objectual content.10 Aristotle agrees with Anscombe about many ordinary transeunt-​causal processes, not so much as a matter of the content of perception, as we have seen, but rather because of the nature of ordinary judgment. He also goes much further, however, insofar as he thinks that for some types of causal kind we are in a position to grasp real definitions through observation as well. Finally, he agrees in a certain way that action provides experiential knowledge of causality, but not so that we can transfer our notion of ourselves as agents to ordinary objects. Rather, action—​specifically the kind that deploys expert practical knowledge—​is important for giving us knowledge of teleological relationships and of efficient causes that act “for the sake of something.”

11.3.  The Nature of Blood I have argued that Aristotle approaches causal explanation in nature by way of a search for the real definitions of natural kinds, which include a broad array of transformations, beings, and activities, and thus are not restricted to substances, even if, in a variety of ways, substances are fundamental to the account of nature as a whole. The search for such definitions involves an array of cognitive tools, but we have grounds for optimism, on his view, insofar as some causality is, scientifically speaking, wholly manifest to our powers of observation under the right conditions. As I have put it, some causality is just as it appears. We thus move from a grasp of more Familiar causality to more Intelligible (and sophisticated) causality, but not from a cause-​free image of nature to a causally implicated one. To assess the extent to which the view I have described answers to his general claims about causes, it will help to observe it at work in an example, which will allow us to see how Aristotle envisages epistemic progress beyond what I have described as our starting points and also serve to raise some final philosophical questions and challenges. Once again, I think it is useful to focus



10 Compare Reid 1788/​2010, 36; Armstrong 1997, 211–​16; and Lowe 2001.

The Non-Secret Connexion  245 on cases other than substance for this purpose, since substance presents so many special challenges.11 A particularly helpful case, which can both illustrate the theory as I have described it and be illuminated by it in parts, is Aristotle’s discussion of blood, the “nature” (phusis) of which is the explicit topic of Parts of Animals II 2–​3.12 His discussion of it is relatively succinct and straightforward, despite some important puzzles, and illustrates both the metaphysical and epistemological features of the view I have attributed to him. The PA is explicitly a work of causal explanation, which draws its explananda from the kind of descriptive work on display in the Historia Animalium—​which focuses especially on describing animal bodies and their activities, but with a special focus on parts.13 The explanations in the PA are generally but not exclusively teleological, in keeping with the fact that the most important parts and features of animals are teleologically determined, and those that are not tend to be derivative, regular results of teleological kinds or processes. Blood is of special importance and interest for several reasons besides the obvious ways in which life depends on it. As Aristotle’s discussions make clear, there were a variety of different opinions about its nature, function, and properties, including whether or not it constitutes a part of the body in the proper sense, whether it has a cognitive or perceptual function, and, what takes up a surprising amount of discussion, whether being hot is part of its essence or not.14 Unlike the basic chemical interactions of Mete. IV, blood therefore presents puzzles, and a combination of observation, inference, and hypothesis is required to give a causal explanation of its nature. Blood is also important in view of its special connection to the heart, which, for Aristotle, is the primary nexus for all of an animal’s primary life functions and the starting point for the development of the embryo.15 For these reasons, an

11 There are other difficulties as well, including the fact that Aristotle does not give us examples of statements of the complete essence of a natural kind, except some toy examples. I have discussed some of the problems of coming to know the essence of a natural substance in Stein 2018. 12 He also gives relevant descriptions of its features, formation, and functions in Mete. IV 7, HA III 19, and GA II 4. See Freeland 1987; Lederman 2014; Ebrey 2015; and Frey 2015. 13 HA I 6, 491a14–​19; on the relation between the HA and PA and their order of composition, see Lennox 1996 and the commentary in Lennox 2001. 14 Lennox 2001, 200, notes that Empedocles may have thought that blood was a kind of flesh, and Aristotle shows some ambivalence as to whether to count it as a part in the proper sense (see Frey 2015, n. 2.) 15 See especially PA III 4, MA 9, and GA II 1.

246  Causality and Causal Explanation in Aristotle account of blood is the first main topic in the body of the PA, after the introductory philosophical and methodological chapters of book I. That the topic is a causal definition of blood as a kind common to a broad division of the animal kingdom (the “blooded” animals) is clear from several mentions of its “nature” (phusis) as the object of inquiry, its account (logos), and the fact that, at the end of the section, we are told that “what it is” has been stated.16 The results of the inquiry may be briefly stated: blood is “the last [stage] of the nutriment” (650a34–​35), and it is “for the sake of nourishing the parts” (650b2–​13). We are thus given a material cause of its production (nutriment), as well as a teleological cause (“nourishing” the parts of the body), which is somehow equivalent to or the main ingredient in the statement of what blood is (as befits an end-​dominant kind). In this context, we should note that the question “How is blood formed from food?” is not one that can properly be asked by the non-​scientist, let alone the question “What is the nature or function of blood?” For only once one has determined that blood is the final result of the transformations undergone by food, according to Aristotle, and therefore that it is what in turn becomes flesh, bone, and so on, is the formation of blood properly framed as being part of the process of nutrition. Establishing that it is an investigable fact with an intrinsic cause thus requires prior scientific investigation. Aristotle arrives at this result in PA II 3 by describing the route food takes from the mouth through the esophagus to the stomach, and from there to blood vessels leading to the heart. That blood is the final state of food is thus only seen, as Aristotle makes clear, by detailed observation of anatomy, including dissections, as well as enough general data to know that all animals possess either blood or an analogous fluid.17 He then gives confirming evidence in the form of using that hypothesis to explain other features, such as the fact that the quantity and quality of one’s blood vary with the quantity and quality of one’s food (650a36–​b8). Thus, in contrast to basic interactions, it takes a great deal of observation and inference to recognize that blood has an intrinsic cause and that this cause is teleological—​that it is the regular result of the activities of nutrition if nothing impedes, and not a co-​incidental

16 The inquiry is into the nature of blood (II 2, 648a20); what it is intrinsically (kath’hauto) and its account (logos) are referred to at 649b25, and its “what it is” (ti ên einai) is referred to at 649b22 (deleted by Peck, retained by Lennox 2001, who notes, ad loc., that this is an application of the concept of essence to the kind “blood”). 17 Cf. HA I 6, 490b7–​14, where the “greatest genera” are divided into blooded and bloodless.

The Non-Secret Connexion  247 but regular by-​product or “residue” of other processes—​before trying to determine what blood really is, that is, to formulate its causal definition. The nature of an animal’s self-​maintaining activity is in fact broken down into two main parts: the conversion of nourishment into something that is potentially a part of its body, and then the transformation of that potential body into actual flesh, bone, or whatever. The matter of the first change is food, and it is only such relative to a given kind of living thing, while the matter of the second change is blood. The first transformation itself is broken up into smaller changes: the food, which is a mixture of moist and dry (650a2–​5), is divided up into smaller pieces to cause good digestion (eupepsia), and then transferred to the stomach, where the stomach concocts blood from it by means of natural heat (650a5–​31).18 These inferences and observations constitute the final stage of Aristotle’s discussion of blood. The discussion as a whole, however, is a rich one, and Aristotle insists at the outset that we must start by reviewing the basic material properties of hot, cold, moist, and dry, the secondary properties they ground, and the interactions they govern as described in the Meteorology, since blood is the result of a kind of concoction—​an application of heat to material (i.e., the food) with a particular range of temperature and moisture, resulting in its transformation into blood.19 The reason we need to begin with elemental properties is that these are clearly implicated in life functions in a way that other material properties are not: Now these disputes seem to occur because ‘hotter’ is said in many ways; for each of the disputants, though saying opposed things, seems to say something [i.e., to have a point]. Accordingly, we should not overlook the question of how, in the case of things constituted by nature, one ought to say that some are hot, others cold, some dry, others moist, since it seems evident that these things are virtually the causes of death and life, and again of sleeping and waking, and being in one’s prime and of ageing, and of sickness and health; but roughness and smoothness are not, nor are heaviness and lightness, nor any other affections of this sort, so to speak. And this result is reasonable; for as has been said previously, in other works, these very



18 Taking the stomach to be the subject of ergasia in ln. 27.

19 Cf. the definition of concoction given and discussed earlier in § 6.4.

248  Causality and Causal Explanation in Aristotle things—​hot, cold, dry, and moist‚ are the principles of the natural elements. (II 2, 648a36–​b10; Lennox tr. modified)20

What is evident, then, is that all living things maintain their bodies by means of nourishment, and that the properties of temperature and moisture are implicated rather than other material properties. The main results of the discussion disambiguating the ways in which things are said to be hot are distinctions between (1) intrinsic and co-​ incidental heat, (2) potential and actual heat, and (3) producing a certain sensation when touched (hot to the touch) and producing flame or burning in a material subject (a source of heat): “it must be determined that this thing is intrinsically hot, while often another is hot co-​incidentally; and that this thing is hot potentially, that one actually, this thing by way of being hotter to the touch, that one by producing flame and fire” (II 2, 649b1–​5; Lennox, tr. modified). These distinctions are then also applied to the other basic properties. The main point of drawing them, in turn, is evidently to be able to state how ‘hot’ features in the definition of blood, but Aristotle’s claim in this regard has been a source of confusion. He states that: Having made these distinctions, then, it is clear that blood is hot in this way, namely in what it is for it to be blood; it is spoken of in this way, just as if we were to indicate boiling water by a [single] name, whereas the subject, i.e. whatever it is that is blood, is not hot. And it is in one way intrinsically hot, but in another way it is not. For heat is present in its account, just as ‘pale’ is in the account of ‘pale man’; but insofar as blood is by virtue of an affection (pathos), it is not intrinsically hot. (II 2, 649b20–​27)21

This set of statements is odd, since Aristotle seems to be saying that (1) ‘hot’ is part of the definition of blood; but (2) ‘hot’ is not predicated intrinsically of its subject when that subject is or constitutes blood. The gloss on having ‘hot’ in the definition therefore makes it look like ‘blood’ is a term for a co-​ incidental unity of a predicate with a subject, such as “pale man,” of which it 20 See GC II 2, 330a24–​5; and Mete. IV 1, 378b10f. (already discussed); as well as Crowley 2008. 21 The main difficulties turn on the notion of the substratum or subject, and how the heat in the definition of blood relates to it; Aristotle refers to this subject as the (“hupokeimenon kai ho pote on haima,” 23–​24), the latter phrase being especially obscure. See Lennox’s commentary ad loc. as well as Lederman 2014.

The Non-Secret Connexion  249 is neither an essential nor a special property;22 however, something’s having ‘hot’ in its theoretical definition would, one have thought, imply being essentially hot. Then again, if blood is a co-​incidental unity the definition of which includes ‘hot’, the reason the relevant subject is not essentially hot would in principle seem to be irrelevant. I think this statement can be clarified when we grasp the causal profile of blood, and what role ‘hot’ could actually play in its definition. Aristotle’s comparison of “pale man” is probably unhelpful, since it makes it appear as though ‘hot’ would be something like a differentiating property, specifying a kind of more general stuff, even if it does not pick out a genuine kind. This is unlikely, since, as we know, blood is going to be essentially a kind of stuff suitable to be transformed by a subsequent process into any of the animal’s parts. It is a natural kind with an end-​dominant causal profile, with its role in nutrition in primary position in its scientific definition. Further, it is an intermediate kind, in the sense that it is intrinsically for the sake of something else—​it is not an ultimate end. Since that is its function—​to be capable of being transformed into flesh and the other “uniform parts,” it is doubtful that Aristotle thinks of heat as in any way its differentiating property, even when considering its teleological nature from the material side of things. Blood’s heat is not like the sharpness of a saw’s edge—​it is not that property by which it is capable of performing its function. Rather, as he says, blood’s heat is from an external influence (“in virtue of an affection,” kata pathos), namely, the proper bodily heat of the animal which concocts the broken-​down food into blood.23 Now, Aristotle is quite clear in De Anima that the efficient cause of nourishment is the soul of the living thing, and that this is the activity which is basic to all living things (DA II 4, 415a22–​25): nourishment is a component of what it is for an animal to be alive.24 We do not fully understand it in any given case, however, until we know what the rest of a living thing’s life activities are, since at least in the case of animals (as opposed to plants) the more basic activities are for the sake of the more developed ones.25 The investigation of nutrition is thus itself a part of the wider investigation into the activities of living things, and so can only be given a partial general account. More 22 See p. 58 for this terminology. 23 Cf. Lennox, commentary ad loc. 24 See Johansen 2012, ch. 7, on this chapter. 25 See especially DA II 3, 414b28–​415a11; II 4, 416b22–​25 (nutrition is for the sake of reproduction); and III 12, 434a30–​b8 (perception is for the sake of motion in non-​stationary animals).

250  Causality and Causal Explanation in Aristotle proximately, however, the animal, if it is of the blooded kind, accomplishes nutrition by means of the natural or “vital” heat in its stomach (PA II 3, 650a2–​14). In other words, the reason ‘hot’ is part of the definition of blood is that blood’s intrinsic efficient cause—​something we do not discover until we know that blood is the final state of nutriment for the sake of nourishing the body’s parts—​is in fact the nutritive faculty of the animal’s soul, which operates by means of “vital heat.” So heat is included in the scientific definition of blood, but for specifying its efficient cause, not as an intrinsic property of the material subject in either its original or in its final state.26 The real definition of blood would thus be something like this: “the final, liquid state resulting from the transformation of broken-​down food, by the action of vital heat, for the sake of nourishment of the parts of the body.” The broken-​down food, having the right degree of temperature and moisture, is, of course, the material cause of the transformation, and the final, liquid state is the “formal cause” in the sense of being the terminal state of the transformation. And, in response to a question, “Why is food transformed into just this state?” the answer will be the teleological cause, in primary position. This profile thus gives a clear example of the way in which, for end-​dominant kinds, the efficient cause can only be specified in relation to the end.27 That this is the nature of definitions for profiles of this sort is also, I think, helpful in understanding some other puzzling aspects of the discussion of blood. One is that, although Aristotle claims to be giving an account of blood specifically, which should mean something that applies only to blood and not to its analogue in bloodless animals, he focuses almost exclusively on the nutrition-​related features that are evidently common to both blooded and bloodless kinds.28 Further, and relatedly, despite all the insistence on the importance of understanding the natures of the basic qualities, he gives very little in the way of any specification of the properties of blood as such, though he goes on to note differentiating features like fibrousness and thickness, which he connects to differences in the parts for which it is suitable and the psychological features of the animal.29 This relative indifference to the physical qualities of blood makes sense if Aristotle is conceiving of his task in the way I have described it. The physical qualities of blood as such are just those manifest observable features it has

26 Cf. PA III 5, 667b21–​31.

27 It is thus a clear application of the distinctions drawn earlier, especially § 7.4. 28 See Lennox 2001, 190. 29 II 4, 650b14f.

The Non-Secret Connexion  251 when it has been generated from food. They are not the objects of a causal inquiry, but rather the features that would be present in a pre-​theoretical account or description of what blood is. Causal inquiry shows us why blood exists, that is, why something is transformed so as to have these features, and, since blood has an end-​dominant profile, the unity of those features is due to their ability to ground that function—​they are more like the physical features that go into being a functionally suitable house, rather than an independently determinate property. There is thus no need to look for further differentiating features for blood as opposed to its analogue, since these are just its various observable qualities and its proximate matter, the latter of which is also evident from observation, once we are aware that blood is in fact the final state of nutriment. The scientific definition of blood, then, begins with manifest data about its features and its importance for life, but those data raise questions about what it is and what sort of role it has.30 Because it results from a type of concoction, which is a basic type of origin-​dominant interaction that can be understood on the basis of observational concepts, we have a starting point in what is Familiar that is then extended and incorporated into a causal definition of an end-​dominant transformative process.

11.4.  Summary: Causal Explanation and Aristotle’s Empiricism Commentators have little to go on for understanding the sense in which Aristotle thinks knowledge comes from experience, and what kind of empiricist or rationalist he is—​if either classification is ultimately suitable. As we have seen, Aristotle gives us scant details in his brief remarks about induction and our cognitive progress from perception to understanding or first principles, which have nonetheless received the majority of attention in this context. The last few decades have, however, seen a great deal of work focusing on Aristotle’s scientific method and practice, especially in biology, in ways which have connected his work in natural science to the theory of demonstration given in the APo., as well as, of course, to his general approach to 30 The pre-​theoretical data about blood evidently include that it is hot in its natural state (Mete IV 11, 389b7–​11), though we do not know if it is hot in its ousia; according to De Somno 3, it is manifest from observations, including dissections, that food is converted into blood, which belongs in the veins, and that these terminate in the heart, to which the concocted blood proceeds (456a32–​b5).

252  Causality and Causal Explanation in Aristotle teleology. But these studies generally presume that Aristotle has answered questions about his predecessors’ explanatory reductionism, and so do not aim to show how his scientific work might relate to those answers or the theory behind them, or to more general epistemological worries, except in light of his defense of natural teleology.31 Discussions of Aristotle’s empiricism have therefore not generally taken account of the details of his theory of causality, despite its clear importance—​ details which are notably absent from the APo. discussion of understanding in any case. Thus, we know Aristotle’s empiricism and his claims about induction somehow go together, and we know that causality is central for knowledge as well—​but it is not apparent how all of these pieces are supposed to cohere. A key feature of Aristotle’s view as I have reconstructed it is that at least some causality is just as it appears: there is no necessary gap between appearance and reality that we overcome in moving from a grasp of a phenomenon to a grasp of its causes, as long as our observations are sound. These manifest types of causal phenomena need not be ontologically or metaphysically basic. All that is needed is that our initial grasp of causality, which allows us to work up to a more demanding task of grasping more theoretical and sophisticated forms of causality, in contrast to reductionist views, is not based on mere belief or a hypothesis. This allows Aristotle, as he sees it, to claim an epistemological advantage over his predecessors. We can raise a worry that the kinds of causality that are most important for natural science are ultimately so far removed from the kinds that are just as they appear that we cannot be confident of that our conceptual starting points are really capable of being extended as far as they need to be. However, the claim that they are so removed needs defending as well, and indeed responding to it is an important task for many theories of causal explanation. Craft production plays an epistemological role here, too, insofar as a correct understanding of it allows us to posit teleological relations in nature by means of an inference rather than a hypothesis. That is, craft production, properly understood, reveals the same types of priority relationships among its stages that we see by close observation of natural processes, and it makes use of the same basic stock of natural (origin-​dominant) interactions. Thus, while there are several ways in which Aristotle appeals to crafts and 31 There have been other more speculative exceptions like De Groot 2014, which focuses on the Mechanics, a work that may have been done in the Lyceum but is not by Aristotle.

The Non-Secret Connexion  253 craft-​products as analogous to a target-​phenomenon he wishes to clarify (such as substance), in the case of causality the relationships are not analogous but rather simply the same. Now, in Aristotle’s discussion of blood, as I have reconstructed it, we have a fragment of a scientific inquiry into the causes of a whole natural process. The self-​maintaining activity of living creatures (nutrition) is divided according to the manner in which it occurs (internally as in animals, or using external materials already at the right level of potentiality, as in plants PA II 3, 650a20–​23), and then the material subject in which it occurs (a transformation of blood or something else). The process in blooded animals is then divided into two main stages, in which food is first transformed into blood, and blood is then integrated into a specific part of the animal. Then, since transforming food into blood is a kind of concoction, we determine the precise characteristics of the food and of the animal’s body by which it is capable of breaking the food down and then acting on its moisture in order to transform it into blood. The process of nutrition is thus analyzed into sub-​ processes until we reach basic interactions, which are already understood. The full explanation of even the details about the nature of the food insofar as it is the subject of the change into blood, however, depends in part on having a full account of the animal’s whole way of life—​what it does, how it procures food and reproduces, and so on—​as well as the nature of its body, by which it performs those life activities. Thus, the analysis is not reductive, since the ultimate intrinsic causes of the transformation are the animal’s soul and the function of nutrition and growth. To say that nourishment is simply a process in which the parts of the animal, using vital heat, transform food into blood, even ignoring the final step of transforming blood into bodily parts, is too simplistic. The scientific answer must give us the determinate features that make a given type of animal capable of transforming a specific type of material into blood, and it must recognize the discrete causal components that are built up into a whole complex process. In doing all this, we may be said to have advanced from a confused whole, in which these divisions were not at all apparent, to an understanding of the main articulations in the natural process of a thing’s self-​organizing and self-​ maintaining activity. We do this by understanding the intrinsic causes of each component of the complex whole, such that we have a causal account of the determinate features of various beings by which they are capable of performing certain activities, including acting on certain stuffs to integrate them into their own bodies. Perhaps this too would be one way in which our

254  Causality and Causal Explanation in Aristotle progress might be characterized as moving from universals to particulars, or from a state like calling all men ‘Father’ to one in which we identify individuals. In Phys. I we are told that induction is a matter of going from a confused whole to clear particulars; in Phys. II we learn that we achieve knowledge of nature by “leading” natural changes back to their causes. The analysis of blood, I suggest, lets us see how these characterizations of natural science can fit together. They also fit with Aristotle’s epistemological goal as I have interpreted it, insofar as it relates to his rejection of the different kinds of reductionism. On those views, the ultimate principles which would be most Intelligible are also the most remote from the objects with which we begin, which are the ones we set out aiming to understand. This would yield understanding of the natural objects by means of principles that are not intrinsically related to them—​and perhaps even only co-​incidentally so. On this reconstruction of Aristotle’s view, the principles are not remote from what they are principles of; rather, we move instead from a pre-​theoretical to a scientific grasp of the natural kinds themselves, in virtue of grasping causes which are intrinsic to them, but which are not evident from our starting points in what is Familiar.32

32 This aspect of Aristotle’s aim in the Phys. is nicely made by Falcon 2018: “Our journey begins with the things that are closer to sense-​perception. It is because we want to know them that we engage in the search for the relevant principles. In this sense, the things closer to perception are not just the starting point of our inquiry; they are also the end of the entire scientific enterprise” (55).

Conclusion The main aim of this book has been to get a full philosophical picture of Aristotle’s theory of causality, on the assumption that he has one, so that we can see how it fares in his debates with his predecessors, how it might fare or be developed in general, and to understand, as with any full philosophical theory, not just what it says about its subject matter but what it implies about how we should approach that subject matter itself. As to the theory, I have argued that he applies a general framework suited to explaining anything with a predication-​like structure, governed by a distinction between what holds of something “in virtue of itself ” and what holds of it “in virtue of something else,” to the task of giving real definitions of the broad array of transformations, beings, and activities that have intrinsic causes—​a task made possible by the fact that there are such things in nature. But because nature is complex, the causal profiles of these natural kinds are not uniform, and so there are important distinctions to be drawn between the different roles causes will play in their causal definitions, and the relations those causes bear to what they cause. Of particular importance is the distinction I have drawn between origin-​dominant and end-​dominant profiles. This complexity results from a rejection of the kind of view I have described as explanatory reductionism, one which seeks to explain all natural phenomena in a uniform way, typically by reference to a metaphysically privileged class of entities. If there is causal unity or uniformity to be found in nature, for Aristotle, it is because some natural phenomena are themselves causally unified, and because nature as a whole has a coherent structure in a well-​ordered universe, not because causality itself admits of a uniform treatment—​and there are, nevertheless, a variety of different ways in which natural phenomena exhibit unity which need to be distinguished, as well as many causally explicable phenomena, even regular ones, which resist unification. As a general approach to causal explanation, this view shares a great deal with the contemporary family of views known as neo-​mechanism, both in its general structure and its anti-​reductionist motivations, as well as its

Causality and Causal Explanation in Aristotle. Nathanael Stein, Oxford University Press. © Oxford University Press 2023. DOI: 10.1093/​oso/​9780197660867.003.0013

256  Causality and Causal Explanation in Aristotle potential limitations. If Aristotle’s view has a natural home among contemporary theories, it is among the neo-​mechanists. I have also argued that a better understanding of Aristotle’s theory of causal explanation is necessary to understand Aristotle’s views about scientific knowledge (epistêmê), and how the theory described in the APo. and other highly general passages might (or might not) relate to his views about knowledge in the natural sciences in particular, especially since these general discussions do not take into account either the complexity of his distinctions or his views about how his predecessors were mistaken about causes in particular. On this topic, any treatment must be more speculative, since Aristotle does not confront it directly. I have argued that on Aristotle’s theory, the different modes of causality also involve epistemic asymmetries, such that certain types of cause, especially efficient causes, are more Familiar or epistemically accessible than others, especially the causes of primary substance. This implies that the cognitive tasks associated with coming to have scientific knowledge of different types of causal profile will also be different, and that certain types of causal profile, especially origin-​dominant ones, are knowable on the basis of simpler cognitive operations than others. Here, too, Aristotle is a pluralist, and the pluralism makes a difference to the way he can answer questions about how we move from perception to understanding. Indeed, I have argued, Aristotle’s suggestion in the APo., that sometimes observation is a sufficient condition for coming to grasp the full causal nature of a given phenomenon, expresses an epistemologically important claim with respect to both his anti-​reductionism and his general idea that our starting points in perception are sophisticated enough for us to be able to reach the kind of high-​grade scientific knowledge we seek. This is the claim that some causality is just as it appears—​it looks the same in the manifest image as it does in the scientific image—​and so can be fully understood without any need to go beyond or behind the appearances. In the science of nature, many complex phenomena will be built up out of those basic ones, and so Aristotle would be in a position to claim that something like epistemic warrant is also available right from the start, with respect to a class of epistemically basic causal phenomena. This general claim applies quite naturally to the scientific definitions of various origin-​dominant causal kinds, especially the “chemical” interactions described in the Meteorology, as well as to craft-​processes, both of which Aristotle, I think, treats as especially manifest to our powers of observation. Both components of the view are thus soundly attributed to

Conclusion  257 him independently of one another; whether he deliberately combines them or considered these phenomena in light of that principle is unclear, but it makes for a coherent theory that addresses some of the challenges he raises. The epistemic asymmetries between different types of cause and causal profile thus allow for a kind of cognitive progress to be described, from those that are more intelligible on the basis of observation to those that require more intellectually sophisticated cognitive tools, which is one of the most important features of his accounts of induction. There are some ways in which his more abstract writings about scientific demonstration and epistemic progress prepare us for the view I have described, and others in which the fit is less clear. A fundamental tension I noted in the Introduction (§ I.3) is that we aim to understand things as they are in themselves, but causal explanation requires appealing to other entities that have some kind of priority over them. This tension implicates our second-​order views about how we should approach causality and causal explanation. Aristotle thinks his predecessors, by emphasizing the importance and priority of these other entities, lose their grip on what they were trying to understand in the first place, and so the best we can achieve on their views is a kind of “co-​incidental” knowledge of natural things. For example, a Platonist may think, according to Aristotle, that ultimate realities are what they are in virtue of themselves, and are therefore wholly intelligible; by contrast, things that are what they are in virtue of something else are not intelligible in their own right, but only relative to something else, and so not wholly intelligible. Or so the Platonist should admit. Aristotle would reply by saying that some things are essentially what they are partially in virtue of themselves and partially in virtue of other things; but this relationality does not diminish their intelligibility, nor does the fact that they are not ultimate realities themselves. We can understand them fully by understanding precisely the ways in which they are what they are in virtue of themselves as well as in virtue of other things.1 Likewise, we should not accept the kind of anemic view of experience that makes it seem we can only apply causal concepts by introducing them from outside, which again seems to hobble our project from the start. Thus, our approach to causality and causal explanation should attempt to satisfy the demand for genuine intelligibility without giving in to the temptation to oversimplify either in our metaphysical assumptions or in our understanding of experience. 1 We might put this as the point that the intrinsic/​relational (kath’hauto/​kat’allo) distinction does not collapse into the intrinsic/​co-​incidental ( kath’hauto/​kata sumbebêkos) distinction.

258  Causality and Causal Explanation in Aristotle Complex phenomena require complex explanations, and a corresponding array of explanatory tools and distinctions. Finally, with respect to two of the most significant modern questions I have raised—​What is the metaphysical relationship between causes and effects? And can we observe causality, or are causal relations always grasped by a further “intellectual operation”?—​Aristotle’s answers are, I think, both philosophically interesting and not at all straightforward. Causes and their effects are discrete in some ways and not in others, depending on the type of causal profile involved and the type of discreteness at stake. Because of his analysis of basic transeunt interactions, he is able to give a reasonable gloss on the discreteness of cause and effect which still preserves the kind of intrinsic-​yet-​contingent connection that makes theorizing about causation so difficult. Nevertheless, it is surprising just how far his own ideas about paradigmatically causal interactions are from the kinds of case around which so much modern theorizing has been done, many of which he would view as peripheral to an account of causality. His views about the observability of causation also to some extent flow from his views about the nature of basic interactions, and they fit nicely for some cases with what I have called a kind of Causal Observationalism. Indeed, they match in one dimension with the kind of view according to which many types of causality are no less observable than are other basic kinds or predicates that enter into ordinary perceptual judgments. On the other hand, his view as far as I have reconstructed it is silent on whether or not this is a matter of the content of perceptual states as such, which is how the question is often framed in contemporary work, nor is it the main focus of Aristotle’s own worries about the way causality is or is not present in the manifest image of nature. Most significantly, perhaps, his view rejects two common modern assumptions, both of which have both metaphysical and epistemological importance: on his view, causality is not to be analyzed as supervenient upon a basic set of non-​causal facts, and the scientific progress by which we come to know the causes of things is not to be characterized in terms of a shift in which an ordinary or “folk” ontology is replaced by a theoretical or scientific one. Aristotle’s theory as I have reconstructed it has limitations and is, of course, open to objections, some of which I have noted already. Because of the way he presents his own views, his accounts of causality can look more like a list of statements which may or may not be true, and whose status and

Conclusion  259 import as a philosophical theory, despite their obvious historical importance and influence, is not apparent. As I have tried to show, Aristotle does have a coherent theory that responds to the worries he raises for his predecessors, that shows how he can connect causality to the human desire to understand, and that can be usefully developed and criticized in turn as an answer to the philosophical challenges that make causality such a compelling topic.

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Index Locorum For the benefit of digital users, indexed terms that span two pages (e.g., 52–​53) may, on occasion, appear on only one of those pages.  ARISTOTLE  Categories  2, 1a20–​1b9  178–​79 4, 1b27  177–​78 4, 2a3–​4  229 9, 11b2–​4  229 Prior Analytics  I 30, 46a17–​27  214 Posterior Analytics  I 2, 71b9-​12  57, 199–​200 I 2, 71b33–​72a5  206 I 2, 72a1–​3  207 I 2, 72a1–​4  43–​44 I 2, 72a7f.  30–​31 I 3, 72b18–​25  209–​10 I 4, 73a34–​b16  58 I 4, 73b7  58 I 13, 78a39–​b4,  153–​55 I 22, 83b18–​24  57 I 24, 85a23–​25  57, 58 I 31, 87b28–​88a2  210–​11 I 31, 88a3  226–​27 I 31, 88a9–​17  210–​11 I 31, 88a13  226–​27 II 1, 89b23–​35  212–​13 II 1, 89b36–​90a7  226 II 1, 89b36–​90a23  212–​13 II 2, 90a7–​15  63 II 2, 90a14–​23  226 II 2, 90a24–​25  226 II 2, 90a26  226 II 2, 90a26–​27  226 II 2, 90a26–​30  210–​11 II 2, 90a27  226–​27 II 2, 90a28–​30  226

II 2, 90a31–​34  112 II 8, 93a5–​6  58 II 8, 93a17–​18  210–​11 II 9, 93b21  58 II 9, 93b21–​28  58 II 11, 94a20–​34  62–​63 II 11, 94a23–​27  66 II 11, 94a28–​34  64 II 11, 94b27–​28  64–​65 II 12, 95b1–​13  195 II 16, 98a36  27 II 16, 98b3  27 II 19, 99b17–​22  209–​10 II 19, 99b20–​34  44 II 19, 99b32–​100b5  214 II 19, 99b38  208 II 19, 100a15–​b5  211 II 19, 100a17–​b1  216 Topics  I 1, 100b21–​23  85–​86 I 4, 101b15–​36  64 I 5, 101b38–​9  56 I 5, 102b4–​26  57 I 9, 103b23  178–​79 I 11, 104b1–​5  64 I 12, 105a13  206 I 15, 106a1–​8  57 V 5, 134a18–​25  57 VI 4, 141b3–​14  43–​44, 207 VI 4 141b3–​142a16  206 VI 4, 141b9–​14  214 Physics  I 1, 184a2–​3  211 I 1, 184a15  30–​31 I 1, 184a16–​21  206 I 1, 184a24–​25  211

274  Index Locorum Physics (cont.) I 1, 184a26–​b13  211 I 2, 184b24–​185a14  101–​2 I 2, 184b25–​a20  37–​38 I 2, 185a12  37–​38 I 4, 187a26–​b13  44 I 4, 187a26–​188a18  44–​45 I 5, 188a32  75 I 5, 188a32–​34  40–​41 I 6, 189a20–​b3  44 I 7, 189b32–​190a31  111 I 7, 190a31f.  57 I 7, 191a8–​12  222–​23 I 9, 192a3–​14  103 I 9, 192a6  50 I 9, 192a7  50 I 9, 192a12  50 II 1, 192b8  31 II 1, 192b8–​32  105 II 1, 192b9–​11  107 II 1, 192b14  105 II 1, 192b21–​4  107 II 1, 192b21–​23  31 II 1, 192b35  107 II 1, 192b35–​193a1  107 II 1, 192b36  31 II 2, 193b22–​30  60 II 2, 193b32–​194a5  113–​14 II 2, 194a1–​7  31–​32 II 2, 194a3–​7  61 II 2, 194a7–​8  60–​61 II 2, 194a21  242–​43 II 2, 194a21–​27  78 II 2, 194a28–​32  224 II 2, 194a35–​36  73, 95–​97 II 2, 194a36–​b8  146 II 2, 194b8  146 II 2, 194b8–​9  145 II 2, 194b13  88, 95–​97 II 3, 194b16–​17  5–​6 II 3, 194b16–​195a8  26 II 3, 194b18–​20  199–​200 II 3, 194b18–​22  118 II 3, 194b20–​2  107 II 3, 194b23–​32  72 II 3, 194b24  28 II 3, 194b25–​33  64 II 3, 194b26–​7  113 II 3, 194b29–​30  63–​64

II 3, 194b30  143–​44 II 3, 194b30–​32  72 II 3, 194b32–​3  63–​64 II 3, 194b34–​35  28 II 3, 195a1–​3  95–​97 II 3, 195a3  26 II 3, 195a3–​4  28 II 3, 195a3–​8  153–​55 II 3, 195a3–​14  27 II 3, 195a4–​8  74 II 3, 195a6  168–​69 II 3, 195a11–​14  78 II 3, 195a15–​26  27 II 3, 195a16–​21  72 II 3, 195a21  72 II 3, 195a21–​23  72 II 3, 195a26  64–​65 II 3, 195a26–​b21  27 II 3, 195a26–​b30  166–​67 II 3, 195a29  26 II 3, 195a29–​b30  76–​77 II 3, 195b7  27 II 3, 195b13–​14  27 II 3, 195b16–​20  179–​80 II 3, 195b17–​21  171 II 3, 195b21–​30  27 II 3, 195b23–​24  167, 169 II 3, 195b24–​25  169 II 4, 195b36–​196a28  32 II 5, 196b20  164 II 5, 196b24–​29  75 II 5, 196b26  169 II 6, 198a1–​14  32 II 7, 198a14–​21  32 II 7, 198a16-​18  153–​55 II 7, 198a22  153–​55 II 7, 198a24–​27  32–​33, 138, 153–​56 II 7, 198a27–​31  95–​97, 172 II 7, 198a31–​33  32–​33 II 7, 198a32,  153–​55 II 7, 198a33–​35  32–​33 II 7, 198a33–​b3  131 II 7, 198a34–​5  64 II 7, 198a35–​b4  32–​33 II 7, 198b4–​9  33, 76 II 7, 198b5–​9  2 II 7, 198b6  164 II 7, 198b9  10 II 8, 198b10  33–​34

Index Locorum  275 II 8, 198b16–​32  33–​34 II 8, 198b16–​199a8  240–​41 II 8, 199a8–​32  241–​42 II 8, 199b13–​18  33–​34 II 8, 199b14–​15  41 II 8, 199b15–​18  224 II 8, 199b17  75 II 9, 200a5–​7  34 II 9, 200a5–​11  146 II 9, 200a11–​15  34 II 9, 200a15–​b4  34 III 1, 200b11–​12  122 III 1, 201a4–​9  122 III 1, 201a9–​15  122, 145 III 1, 201a18–​19  122 III 1, 201a11  83–​84, 119 III 1, 201b5–​15  139 III 2, 201b20  49–​50 III 2, 201b32  178–​79 III 2, 202a9  153–​55 III 3 202a13–​21  174 III 3, 202a21–​b5  122 III 3, 202a30–​31  122 III 3, 202b1–​5  177–​78 III 3, 202b5–​16  174 III 3, 202b13–​14  174 III 3, 202b19–​21  177–​78 III 3, 202b23–​26  123 III 3, 202b26–​27  134 III 3, 202b26–​29  123 III 4, 203a15–​6  50 III 6, 206b28  50 IV 2, 209a31  57 IV 2, 209b11–​16  50 IV 2, 209b33–​210a2  50 IV 3, 210a27–​b10  140 IV 11, 220a18–​20  195 V 1, 223a23–​28  184 V 1, 224a28–​30  121–​22 V 1, 224b11  119 V 1, 225a1–​2  119–​20 V 1, 225a22  120 V 1, 225a34–​b5  119–​20 V 1, 225b5–​9  38 V 2, 225b20–​1  119–​20 V 2, 225b22  119–​20 V 2, 226a10  120 V 2, 226a23–​b9  105 V 2, 226a32–​b1  128

V 2, 226b16–​17  119 V 2, 227b6–​11  121 V 4, 227b3ff.  121 V 4, 227b30  121 V 4, 228a2–​12  121 VI 1, 231b6–​10  195 VII 2, 243a16–​b2  128 VII 2, 244a7  128 VIII 3, 253b6  37–​38 VIII 4, 254b12f.  153–​55 VIII 5, 257b8  178–​79 VIII 5, 258a5–​8  73 VIII 7, 260a27  105 De Caelo  I 3, 286a3–​7  217–​18 III 2, 300a14  195 III 4, 303a8–​10  47 III 4, 303a20–​24  214–​15 III 7, 305b1f.  39–​40 III 7, 306a3–​7  221 III 7, 306a4  39–​40 III 7, 306a5–​11  218–​19 III 7, 306a5–​17  50–​51 III 7, 306a7–​11  50–​51 IV 3, 310a23  105 IV 3, 310a23–​31  41–​42 De Generatione et Corruptione  I 1, 314a8–​11  38 I 1, 314a11–​16  38 I 1, 314b1–​12  38 I 1, 314b15–​26  38 I 2, 315b28–​16a4  39 I 2, 316a5f.  43 I 2, 317a17–​31  39, 77 I 3, 318a9–​10  39 I 4, 319b8–​320a2  42 I 4, 319b31–​20a2  105 I 4, 320a2–​5  81–​82, 145 I 5, 320b21  153–​55 I 6, 323a12–​20  95–​97, 175 I 7, 323b15–​325a24  173 I 7, 324a14–​24  46 I 7, 324a24–​b14  95–​97 I 7, 324a27–​28  169–​70 I 7, 324a30–​34  73 I 7, 324a30–​b13  172 I 7, 324b2  168–​69

276  Index Locorum De Generatione et Corruptione (cont.) I 7, 324b6–​9  66 I 7, 324b17,  156 I 7, 324b18  131 I 8, 325a23–​b5  42 I 8, 325b25–​33  47 I 8, 325b36–​26b6  39 I 9, 327a14–​19  39 I 9, 327a14–​22  40 I 9, 327a23–​25  39 II 1, 328b32–​33  217 II 1, 329a27–​b3  217 II 2, 329a35–​b2  38 II 2, 329b24–​30  108–​9 II 2, 330a24–​5  247–​48 II 4, 331a7ff.  39–​40 II 4, 331a8  221 II 6, 333a35–​b3  38 II 9, 335a32  64–​65 II 9, 335a32–​b5  164 II 9, 335b2–​7  156 II 9, 335b8  48 II 9, 335b10  220 II 9, 335b15–​16  48 II 9, 335b7–​17  48 II 9, 335b18–​20  48 II 9, 335b18–​24  103, 219 II 9, 335b20–​24  48–​49 II 9, 335b24  219–​20 II 9, 335b35–​336a14  46 II 9, 336a3–​12  46, 77 II 10, 336a31–​337a33  95–​97 II 11, 337b35–​338a3  164 II 11, 338b2–​19  88 Meteorology  I 4, 341b5–​12  123–​24 II 3, 357b24  123–​24 IV 1, 378b10–​13  123–​24 IV 1, 378b10–​26  108–​9 IV 1, 378b10f.  247–​48 IV 1, 378b15–​18  123–​24 IV 1, 378b28–​30  123–​24 IV 1, 378b28–​34ff.  123–​24 IV 1, 378b31–​379a5  124 IV 1, 379b8–​9  125 IV 2, 379b17–​18  125 IV 2, 379b18–​20  125 IV 2, 379b25–​30  128

IV 3, 380a12f.  125–​26 IV 3, 380a12ff.  234–​35 IV 3, 380b11–​12  125–​26 IV 3, 380b13–​14  125–​26 IV 3, 381a9–​12  106 IV 3, 381a10–​11  128 IV 3, 381a22–​23  125–​26 IV 3, 381b3–​9  106 IV 3, 381b6  242–​43 IV 4, 382a8–​11  153–​55 IV 4, 382a8–​14  134 IV 5, 382a27–​29  127–​28 IV 7, 383b18–​19  145–​46 IV 7, 383b20–​384a2  IV 8, 384b24–​30  109 IV 8, 384b24–​385a8  233–​34 IV 8, 384b34–​385a6  229 IV 8, 384b34ff.  234–​35 IV 8, 385a10–​12  234–​35 IV 9, 386a9–​17  127 IV 9, 386a18–​20  127 IV 9, 386a25–​33  127 IV 9, 386b19–​22  127, 131 IV 9, 386b27–​387a3  127 IV 11, 389b7–​11  251 IV 12, 390a10–​13  116–​17, 158–​59 IV 12, 390b2–​14  109 De Anima  I 1, 403a25–​b19  113–​14 I 1, 403a26–​27  113–​14 I 1, 403b6–​7  113–​14 I 3, 406a4  14 I 3, 406a4–​8  57 II 1, 412b4–​6  83–​84, 85 II 1, 412b5–​6  152 II 1, 412b18–​20  158–​59 II 1, 412b20–​22  158–​59 II 2, 413a11–​16  206 II 3, 414b19–​34  85 II 3, 414b20–​34  152 II 3, 414b28–​415a11  249–​50 II 4, 415a22–​25  249–​50 II 4, 415b2–​3  73, 95–​97 II 4, 415b8–​9  26 II 4, 415b8–​21  156–​57 II 4, 416b22–​25  249–​50 II 5, 417a16  178–​79

Index Locorum  277 II 6, 418a17–​19  229 III 1, 425a13–​b4  231–​32 III 1, 425a16–​18  229 III 2, 426b9–​427a16  231–​32 III 3, 427b8–​13  208 III 7, 431b5  231–​32 III 7, 431b5–​6  208 III 12, 434a30–​b8  249–​50 De Somno  3, 456a32–​b5  251 3, 458a25–​28  135 3, 458a28–​32  135 On Youth, Old Age, Life and Death, and Respiration  472b27 221 476a12 221 History of Animals  I 1, 486b17–​22  98–​99 I 6, 490b7–​14  246–​47 I 6, 491a7–​11  217–​18 I 6, 491a7–​26  214 I 6, 491a14–​19  245 IV 2, 525a8  219 VIII 12, 597a24–​27  148–​49 VIII 16, 600a22–​25  148–​49 VIII 17, 600a30–​32  148–​49 Parts of Animals  I 1, 639b11  221 I 1, 639b11f.  131 I 1, 639b15  106 I 1, 639b24  164 I 1, 640a13–​19  139 I 1, 640b17–​28  47 I 1, 640b33–​641a5  158–​59 I 1, 641a36  30–​31 I 1, 641b23–​25  224 I 1, 642a8–​11  146 I 4, 644a23–​b7  98–​99 I 4, 644b8–​15  98–​99 I 5, 644b22–​35  217–​18 II 2, 648a19–​649b8  237–​38 II 2, 648a20  246 II 2, 648a36–​b10  247–​48 II 2, 649b1–​5  248 II 2, 649b20–​27  248

II 3, 649b22  246 II 3, 649b25  246 II 3, 650a2–​5  247 II 3, 650a2–​14  249–​50 II 3, 650a5–​31  247 II 3, 650a20–​23  253 II 3, 650a36–​b8  246–​47 II 4, 650b14f.  250 II 8, 653b30  221 III 5, 667b21–​31  249–​50 Motion of Animals  7, 701a29–​36  208 Generation of Animals  I 2, 716a27–​31  169–​70 I 18–​19, 724a14ff.  137–​38 I 23, 731a33  208 II 1, 732b23  95–​97 II 1, 734b19–​735a4  153–​55 II 1, 734b24–​27  158–​59 II 2, 736a1  234–​35 II 3, 736b29–​35  136 II 4, 739b34ff.  137–​38 II 4, 740b18–​741a2  140–​41 II 6, 742a20–​b3  137 II 6, 742a30–​31  137 II 6, 743a1ff.  140 II 6, 743a3ff.  137–​38 II 6, 743a6–​8  137–​38 II 6, 743a21–​26  42, 136 II 7, 746a29ff.  109 IV 1, 765a34–​b6  47 IV 3, 768b15–​25  172 V 1, 778a32–​b19  138 V 3, 782b11f.  138 V 8, 788b21  221 Metaphysics  I 1, 980a1  206 I 1, 980b25–​981a1  206 I 1, 981a5–​12  206–​7, 232 I 1, 981a8–​12  207 I 1, 981a15  43–​44 I 1, 981a15–​17  207 I 1, 981a24–​25  207–​8 I 1, 981a26–​28  207–​8 I 1, 981a30–​b2  207–​8 I 1, 981b10–​13  207–​8

278  Index Locorum Metaphysics (cont.) I 1, 981b11  208 I 3, 983a25–​6  199–​200 I 3, 983a26–​27  26 I 3, 983a34  5–​6, 29 I 3, 984a20f.  45–​46 I 3, 984b11–​15  51 I 4, 985a4–​10  52 I 6, 987b20  50 I 7, 988b6–​16  52 I 8, 989b21–​24  51–​52 I 8, 990a5–​18  47–​48 I 9, 991a8–​b3  47 I 9, 991a19–​b1  50 I 9, 991b3–​9  48 I 9, 991b4–​7  78 I 9, 992a24–​b1  49, 220–​21 I 9, 992a30  220 I 9, 992b1–​7  50 I 9, 992b7–​8  218–​19 I 9, 992b7–​9  49–​50 I 9, 992b9  221 I 9, 992b18–​993a10  44 I 9, 992b24–​993a10  44 I 10, 993a14–​15  1 II 2, 994b27–​31  77–​78 II 2, 994b28  26 III 1, 996a2–​4  51–​52 III 2, 996a19–​20  26 III 2, 996b22–​23  132 III 3, 998a20–​b14  9 III 4, 1000a5–​1001a3  51–​52 III 4, 1001a4–​b25  9 V 1, 1013a16–​17  30–​31 V 2, 1013b15–​16  78 V 5, 1015b9–​12  59 V 7, 1017a7–​30  57 V 18, 1022a14–​22  59, 83 V 30, 1025a14–​34  57 V 30, 1025a20  164 VI 1, 1025b19  30–​31 VI 1, 1025b25–​26a6  37–​38 VI 2, 1026b27–​1027a28  102 VI 2, 1027a3  107–​8 VI 2, 1027a10  164 VII 2, 1028b8–​13  107 VII 2, 1028b9–​13  31 VII 3, 1029a20–​33  61–​62

VII 3, 1029b3–​12  206, 214 VII 4, 1029b24–​25  178–​79, 229 VII 7, 1032a12–​22  102 VII 7, 1032a13ff.  105 VII 7, 1032a20  65–​66 VII 7, 1032a27–​28  169–​70 VII 7, 1032b1–​2  113 VII 7, 1032b11–​14  153–​55 VII 7, 1032b21–​26  242–​43 VII 7, 1032b22–​23  169–​70 VII 8, 1034a4–​5  169–​70 VII 9, 1034a21f.  153–​55 VII 9, 1034b16–​19  169–​70 VII 10, 1035b32–​1036a2  113 VII 10, 1036a9  61–​62 VII 11, 1036b28–​30  113–​14 VII 13, 1038b3–​6  95–​97 VII 15, 1039b29–​30  65–​66 VII 16, 1040b5–​10  107 VII 17, 1041a24-​32  117, 131, 158 VII 17, 1041a28–​30  132 VII 17, 1041b7–​9  67 VII 17, 1041b29  106 VIII 1, 1042a27–​28  65–​66 VIII 1, 1042a32–​b3  145 VIII 2, 1043a4–​12  106 VIII 2, 1043a14–​28  114 VIII 3, 1043b21  106 VIII 3, 1043b21–​23  107 VIII 4, 1044a25–​32  145–​46 VIII 4, 1044a32–​b1  2 VIII 4, 1044a33  26 VIII 4, 1044a36–​b1  158–​59 VIII 4, 1044b3–​15  135 VIII 4, 1044b8–​11  109 VIII 4, 1044b15–​20  135 VIII 5, 1044b27–​29  109 VIII 6, 1045b21  158–​59 IX 1, 1045b36  223–​24 IX 1, 1046a10–​13  223–​24 IX 5, 1048a8–​11  146 IX 6, 1048a25–​30  147 IX 6, 1048a28–​29  223–​24 IX 6, 1048a35–​37  223–​24 IX 6, 1048a37–​b4  180 IX 7, 1049a18–​b3  147 IX 8, 1049b4f.  141–​42 IX 8, 1049b5–​10  146–​47

Index Locorum  279 IX 8, 1049b12–​17  139 IX 8, 1050a4–​b3  139 IX 8, 1050a9  158–​59 IX 8, 1050a15  65–​66 IX 8, 1050a30–​b2  147 IX 8, 1050b2  158–​59 IX 9, 1051a29–​30  158–​59 X 1, 1052b1–​3  84 X 1, 1052b3–​18  73 X 1, 1052b6–​7  84 X 1, 1052b9–​24  84 XI 4, 1061b28  30–​31 XII 1, 1069b9–​14  38 XII 2, 1069b9–​20  145 XII 3, 1070a4–​5  153–​55 XII 4, 1070a31–​b21  97 XII 4, 1070a33–​b10  97–​98 XII 4, 1070b22–​26  81–​82 XII 4, 1070b28–​9  168–​69 XII 5, 1071a1–​2  98 XII 5, 1071a10–​11  65–​66 XII 5, 1071a11–​13  97–​98 XII 5, 1071a13–​17  97–​98 XII 5, 1071a14–​17  95–​97 XII 5, 1071a17–​29  98 XII 7, 1072b1–​3  95–​97 Nicomachean Ethics  I 7, 1098b3–​6  214–​15 I 7, 1098b27–​29  214 VI 4, 1140a1f.  105 VI 9, 1142b2–​6  210–​11 Politics  I 2, 1252b29–​30  139–​40 I 2, 1253a18–​25  158–​59 Protrepticus  Fr. 13 ln. 2  242–​43 Fr. 14 ln. 1  242–​43 PLATO  Meno  74b2–​76e9 

Phaedo  65d4–​66a8  48–​49 66a2 56 74a9–​75b2  48–​49 75c10–​d1  56 78c10–​79a5  48–​49 78c10–​d7  56 96a5–​102a1  48–​49 96a5–​107b10  3–​4 96a8 57 96e6–​97b7  4 98b6–​99b6  220 99b2–​4  103 100a2–​b9  4, 238 100c9–​105c6  219–​20 101d1–​e3  4, 238 102d5–​103a2  57 102d6 56 Parmenides  129d7–​8  56 133a9 56 Philebus  23c–​d  85 Republic  V, 478e7–​480a10  56 V, 478e7–​479e5  4 VII, 522bff.  32 Sophist  255c12–​13  56 Theaetetus  156a5-​7  178–​79 Timaeus  28a4–​6  4 29b1–​d 3  30–​31 46c7–​47c4  4 47e3–​48b3  4 50b5–​52d1  50 51c1 56

Subject Index For the benefit of digital users, indexed terms that span two pages (e.g., 52–​53) may, on occasion, appear on only one of those pages.  abstract (logikôs) vs. natural-​scientific (phusikôs)  116–​23, 179 See also definition; dialectic, dialectical argumentation; natural science (phusikê, phusikê epistêmê) Academy, Plato’s  6n.11, 28–​29, 55, 60–​61, 66n.26, 69n.32, 78n.10, 101–​2, 103 acting (poiein) and being-​acted upon (paschein)  119–​20, 178–​79, 229–​33 See also agent-​patient interactions actuality or activity (energeia)  5–​6, 110n.13, 141–​42, 146–​47, 174–​75, 180n.39, 223–​24 vs. actualization (entelecheia)  174n.23 affections (pathê)  113–​14, 116–​17, 153–​ 55, 247–​49 agent-​patient interactions  40–​42, 72, 95–​ 97, 122, 123–​29, 130, 134, 145–​46, 153n.39, 174–​81, 186–​90, 194, 217–​ 18, 224–​25, 227–​35 See also acting (poiein) and being-​acted upon (paschein) ‘aitia’, ‘aition’  7–​9, 10n.16, 26–​27n.3, 82–​87 See also causes Alexander of Aphrodisias  46n.18, 118–​ 19n.27, 171n.18, 207n.17 analogy  97–​99, 222–​24 in biological kinds  246–​47, 250–​51 Anaxagoras  4, 38, 44, 46n.17, 52, 77, 85 See also reductionism Anscombe, G.  179n.37, 203, 243–​44 appearance and reality distinction  9, 17, 20–​21, 53, 237–​39, 252 See also “more knowable to us” (gnôrimôteron hêmin) vs. “more knowable without qualification (gnôrimôteron haplôs) distinction

appearances (phainomena) 214 See also “more knowable to us” (gnôrimôteron hêmin) vs. “more knowable without qualification (gnôrimôteron haplôs) distinction Aquinas, T.  82n.16, 83 artifacts  as having intrinsic causes  78, 106, 110–​12 as models for causality  106–​7, 222–​23 as models for substance  106–​7 See also craft (technê) atomism  39, 42, 44, 47n.21, 77, 181–​82, 203–​4 See also Democritus; reductionism auxiliary cause (sunaition)  50, 103 Barnes, J.  200n.1, 209n.22, 228n.22 basic “chemical” interactions (from Meteorology IV)  123–​29, 132, 136, 144, 145–​46, 153–​55, 160, 186–​90, 223, 233–​35, 245–​46, 247 See also acting (poiein) and being-​ acted upon (paschein); agent-​patient interactions Burnyeat, M.  81n.14, 114n.21, 200n.1 Butler, J.  20–​21, 100 capacity.  See potentiality (dunamis) categories  40, 95–​98, 105, 128–​30, 177–​ 79, 229–​31 for causal relata  100, 105 See also change; acting (poiein) and being-​acted upon (paschein); predication causal profiles  16, 131–​33 and the account of blood  249–​51 correspondences with other conceptual distinctions  145–​48

282  Subject Index causal profiles (cont.) and epistemic priority  201, 222–​23, 233–​35 material and efficient causes in end-​dominant  146 origin-​dominant vs. end-​ dominant  132, 188 and reductionism  162–​63 causes  actual vs. potential  27n.5, 76–​77, 78, 122, 166–​67, 168, 170–​73, 179–​81, 187–​90, 194 in APo. vs. natural-​scientific works  63–​67 basis for the distinctions among  68–​69, 71–​79 as occupants of second-​order roles  14–​ 15, 72–​73, 77–​80, 95–​99 sameness and oneness claims about  155–​60 terms for  2n.2, 63–​64, 96n.2 “topmost” (akrôtaton)  77, 168–​72 “ways of being causes” in Phys. II 3  165–​73 See also ‘aitia’, ‘aition’; causal profiles; principle (archê); ‘that for the sake of which’ (hou heneka) chance (to automaton) and luck (hê tuchê)  32, 33–​35, 40–​42, 51, 75, 77–​ 78, 85–​86, 108–​9 See also Non-​Random Change (NRC) principle; regularities, natural change (kinêsis)  categorially-​determined kinds of  38, 107, 129–​30 definition of  119, 123 and intrinsic objects of perception  229–​32 Physics III vs. Physics V discussions of  119–​23 See also definition; transformation (metabolê); acting (poiein) and being-​ acted upon (paschein) Charles, D.  112n.16, 121n.33, 132–​33n.6, 176–​77n.30 common opinions (endoxa)  36, 85–​86, 207–​8

concoction (pepsis)  124–​26, 127–​28, 247 conditions vs. causes  2, 34, 89, 103, 146, 175, 189–​90, 195, 199–​200, 220, 228, 235–​36 contingency  57, 102–​4, 163–​64, 194–​95, 196 contraries  41–42, 57, 119–​22 Coope. U.  164n.3, 176n.28, 178n.32 counterfactual accounts of causation  100, 228 craft (technê)  106–​7, 206–​8, 209–​10, 240–​44 building craft (hê oikodomikê) 167, 168–​71 definition  55–​56, 58–​62, 112–​16 of blood  244–​51 of cause  74, 83–​87 and essence  56, 57–​58 of kinds of transformation and change  116–​23, 177–​79 pre-​theoretical  114–​15 theoretical (real, causal)  15–​16, 114–​ 15, 116 types of  200–​1, 213 Democritus  39, 40, 43, 46n.17, 202 See also atomism; reductionism demonstration  6–​7, 209–​10 causes as middle terms in  62–​69 description vs. explanation  61, 89, 163 determinism 164 dialectic, dialectical argumentation  39, 63–​64, 113–​14, 119–​20, 177–​79 See also abstract (logikôs) vs. natural-​ scientific (phusikôs) difference-​making relation, causation as  90–​91, 100 differentia  55–​56, 71n.1 See also genus discreteness  101–​4, 258 dispositional properties  145–​46, 171n.16, 187–​88 See also potentiality division, definition by  55–​56 Dretske-​Tooley-​Armstrong theory of causation  3n.4, 104n.22 eclipse, causal explanation of  109, 135, 160, 226–​27, 235

Subject Index  283 effects, terminology for  27n.4 See also explananda elements, inter-​transformation of  39–​40, 111, 134n.9, 221, 237–​38 Empedocles  30–​31, 37, 38, 39–​40, 41, 44, 52, 77–​78, 240–​41 See also reductionism empiricism  202, 203 Aristotle and  100, 205–​12, 251–​54 See also induction (epagôgê) essence.  See causes; definition essentialism  112–​16, 130, 194 See also definition exhalations, dry and moist  123–​24, 233–​34 experience  202–​3, 214–​15, 236, 239, 243–​44 Aristotelian (empeiria)  43–​44, 206–​8, 232 explananda  basic kinds of  105–​12, 134–​42 for natural science  50 in APo. vs. Phys.  64, 66–​67, 75–​76 fact (hoti) vs. Why (dioti)  212–​13, 225 See also inquiry, stages of Familiar vs. Intelligible. See “more knowable to us” (gnôrimôteron hêmin) vs. “more knowable without qualification (gnôrimôteron haplôs) distinction final causes.  See causes; teleological explanation; ‘that for the sake of which’ (hou heneka) “folk”-​concepts  90–​91, 203, 258 “for the most part” (hôs epi to polu) regularity  133, 164n.3, 190–​91 form.  See causes Forms, Platonic.  See Plato; Platonic Forms; Platonism Frede, M.  8n.13, 8n.14, 167n.6, 168n.9 generation (genesis) and destruction (phthora).  See transformation (metabolê) genus  55–​56, 57, 66–​67, 71n.1, 72 Gill, M. L.  58n.9, 122n.34, 135, 172n.20, 176n.29 Gotthelf. A.  143–​44n.28

Great and Small, the  49–​50 See also Plato; Platonistm grounding  10–​11 heat  as active power in basic interactions 123–​29, 145–​46, 153–​55, 188, 233–​35 ambiguity of  237–​38, 247–​48 relation to definition of blood  245–​46, 247–​50 vital  135, 136, 247, 249–​50, 253 Henry, D.  25–​26n.2, 46n.18, 136n.13, 143–​44n.28 Hume  4–​5, 83–​84, 102, 103–​4, 181–​82, 195, 196, 202, 203, 228, 243–​44 Humeanism  3–​4, 101, 103, 182–​83, 184–​ 85, 234n.29 Hume’s dictum  181–​86 Hussey, E.  176–​77n.30, 178n.33 hylomorphism  10–​11, 25–​26n.2, 61–​62, 66–​69, 75–​76, 80–​81, 88, 157, 159–​ 60, 215, 218, 223–​24 See also change (kinêsis); substance (ousia); transformation (metabolê) immediate vs. mediated causality  95–​97, 144, 152–​55, 186, 188 See also moved movers; unmoved movers independence, existential  56, 102–​4, 183, 187–​90 See also discreteness induction (epagôgê)  200–​1, 205–​12, 214–​ 15, 223–​25, 232–​33, 235–​36, 237, 238, 251–​52, 254, 257 See also inquiry, stages of induction, modern problem of  228 inference  17, 182, 201n.4, 224–​26, 228, 235n.31, 238, 243, 245–​47 vs. hypothesis  252–​53 influence.  See counterfactual accounts of causation inquiry, stages of  114–​15, 200–​1, 212–​16, 228 instrumental causes  95–​97 See also immediate vs. mediated causality

284  Subject Index intellect (nous)  209–​10 See also induction; scientific knowledge intelligibility  30–​31, 43–​44, 51–​52, 53, 61–​62, 70, 74, 77, 104, 115, 152–​53, 162–​63, 181–​82, 191–​92, 199–​200, 215–​16, 240, 243, 257–​58 See also “more knowable to us” (gnôrimôteron hêmin) vs. “more knowable without qualification (gnôrimôteron haplôs) distinction Intelligible.  See “more knowable to us” (gnôrimôteron hêmin) vs. “more knowable without qualification (gnôrimôteron haplôs) distinction intrinsic (kath’hauto) vs. extrinsic distinctions  14n.21, 31, 57–​58, 257n.1 applied to causes  58, 74–​76 applied to necessity  59 applied to predication  68 intrinsic (kath’hauto) vs. co-​incidental (kata sumbebêkos) distinction  see causes, “ways of being causes” in Phys. II see also perception, intrinsic (kath’hauto) vs. co-​incidental (kata sumbebêkos) intrinsic (kath’hauto) vs. ‘in virtue of something else’ (kat’allo) distinction  57, 59, 257n.1 ‘in virtue of ’ (kath’ho), Aristotle’s analysis of  59–​60 Kant, I.  3–​5, 103–​4, 195, 196 knowledge.  See intellect (nous), scientific knowledge (epistêmê), wisdom (sophia) Kosman, A.  210n.24 laws of nature  20n.25, 90–​91, 102, 165, 191–​93, 195 Lennox, J.  128n.46, 143–​44n.28, 191n.51, 245n.14, 246n.16 Lewis, D.  103n.18 See also counterfactual accounts of causation Lloyd, G.  124n.39, 125n.42 luck.  See chance (to automaton) and luck (hê tuchê)

Machamer, Darden, and Craver  190–​93 See also neo-​mechanism manifest image vs. scientific image  17, 202–​5, 217–​23, 225–​26, 258 See also appearance and reality distinction; “more knowable to us” (gnôrimôteron hêmin) vs. “more knowable without qualification (gnôrimôteron haplôs) distinction; Sellars. W. Marmodoro, A.  176–​77n.30 mathematics  5–​6, 30–​32, 34, 47–​48, 49, 58, 69–​70, 220–​21 distinguished from natural science  34–​ 35, 60–​62 matter.  See causes; change (kinêsis); potentiality (dunamis); transformation (metabolê) mesentery  143–​44 Meyer, S.  51n.28 modality  103–​4, 145–​46, 164, 183, 187 See also actuality or activity (energeia); contingency; necessity; potentiality (dunamis) models  27–​28, 81–​82, 106–​7, 240 See also analogy monism  Eleatic  37–​38, 42, 101–​2 material  30–​31, 38 “more knowable to us” (gnôrimôteron hêmin) vs. “more knowable without qualification (gnôrimôteron haplôs) distinction  17, 123, 206, 208–​9, 213–​ 14, 216, 222–​24, 225–​26, 235–​36, 244, 256–​57 See also appearance and reality distinction; intelligibility; manifest image vs. scientific image moved movers  73, 95–​97, 172–​73n.21, 180n.40 See also self-​movers; unmoved movers multivocity of ‘cause’  26–​27n.3, 83–​85 See also pluralism, causal Natali, C.  85 natural science (phusikê, phusikê epistêmê)  30–​31, 43, 69, 107, 116, 141, 211–​12, 215, 238

Subject Index  285 connection to change (kinêsis)  38, 50 See also abstract (logikôs) vs. natural-​ scientific (phusikôs); mathematics, distinguished from natural science necessary conditions.  See conditions vs. causes necessary connection, problem of.  See non-​accidentality necessity  hypothetical  34–​35, 146 nomological  100 (see also laws of nature) simple (haplôs)  34 (see also intrinsic (kath’hauto) vs. extrinsic distinctions) neo-​mechanism  19–​20, 190–​93 non-​accidentality  102–​3, 165, 185–​86, 194–​95 See also necessity non-​causal states of affairs  19–​20, 175, 180–​81, 202, 227–​28, 236, 258 See also supervenience Non-​Random Change (NRC) principle  40–​42, 74–​75, 79, 191 See also regularities, natural nous.  See intellect nutrition  143, 148–​50, 246–​47, 249–​50, 253–​54 omentum  143–​44 ontology  72–​73, 79, 105–​7, 202 special (see reductionism, explanatory) See also reductionism, explanatory vs. ontological Organon, the  65–​67, 68–​69, 80–​81, 121–​22 See also dialectic, dialectical argumentation; abstract (logikôs) vs. natural-​scientific (phusikôs) Pacius, J.  210n.26 Parmenides  30–​31 See also monism, Eleatic particular(s)  27, 43–​44, 103–​4, 166–​68, 207–​8, 209–​10, 211, 215–​16 See also experience, Aristotelian (empeiria); universals perceptible(s)  43–​44, 47–​48, 52, 102, 217, 234–​35 need for perceptible causes of  218–​19 See also perception

perception (aisthêsis)  202–​3, 208, 211–​12, 216, 217–​18, 219–​22, 226–​32, 233 capacities of  42 causality and the contents of  203, 230–​ 31, 243–​44 intrinsic (kath’hauto) vs. co-​incidental (kata sumbebêkos)  229–​30 See also experience (empeiria); induction (epagôgê); particular(s) Plato  3–​4, 30–​32, 39, 44, 47–​50, 55–​57, 60–​62, 77, 78, 85–​86, 89, 102–​4, 155, 179–​80, 202, 207, 220–​21, 231–​32, 243 treated as a kind of explanatory reductionist by Aristotle  47 See also Platonism Platonic Forms  3–​4, 44–​45, 47, 48–​50, 56, 57, 75, 103–​4, 179–​80, 199, 219–​21 See also Plato, Platonism Platonism  28–​29, 48–​50, 52, 75, 155, 203–​ 4, 218–​21 See also Plato polis  139n.19, 143–​44n.28 potentiality (dunamis)  48–​49, 110, 119–​ 20, 121–​22, 126–​29, 145–​46, 172–​73, 177–​78, 187–​90, 217–​18, 219–​20, 223–​24, 236 See also acting (poiein) and being-​ acted upon (paschein); actual vs. potential causes; actuality or activity (energeia); change (kinêsis); matter power.  See potentiality (dunamis) powers theories of causation  171n.16 predication  in APo. four-​causal schema  64–​70 See also intrinsic (kath’hauto) vs. extrinsic distinctions Principle of Causal Synonymy (PCS)  10, 153–​55 principle (archê)  34–​35, 152–​53, 160–​61 causes as principles of change (kinêsis) and transformation (metabolê) 32–​ 33, 83, 146–​47, 169–​71, 172, 181 of scientific knowledge (epistêmê)  30–​31, 58, 209–​10 See also cause, “topmost” (akrôtaton) privation  30–​31, 50, 97, 119–​20, 122

286  Subject Index problems (problêmata) 64 propria  57, 95–​97, 115 psychology.  See soul (psuchê) Ptolemy 2n.2 Pythagoreans  47–​48 quick wit (agchinoia) 210n.26 rationalism  182, 205–​6, 207, 209, 216, 251–​52 See also empiricism reductionism  37–​44 explanatory  44–​53 explanatory vs. ontological  44–​45 See also Anaxagoras, Democritus, Empedocles, monism, Plato regularities, natural  41, 42, 51, 75–​76, 133–​34 See also Non-​Random Change (NRC) principle Robin, L.  73n.4 Ross, W. D.  25, 27–​29, 89n.23, 118–​ 19n.27, 176, 220n.10 Scholasticism  10–​11, 237 scientific knowledge (epistêmê)  1, 30–​31, 34–​35, 109–​10, 199, 209–​10 See also induction; inquiry, stages of; natural science (phusikê, phusikê epistêmê) self-​movers  39, 95–​97 Sellars, W.  202 See also manifest image vs. scientific image, “more knowable to us” (gnôrimôteron hêmin) vs. “more knowable without qualification (gnôrimôteron haplôs) distinction Simplicius  170n.15 sleep  135 snub, the  31–32, 61, 141 Socrates  55–56 See also Plato soul (psuchê)  affections (pathê) of  116–17 as cause of the body  156–58 as cause of nutrition  143 definability of  83–84, 85, 152

special properties  58, 134–35, 138, 248–49 species.  See causes; essentialism Suárez, F.  83n.19, 85, 86–87, 223n.17 subject (hupokeimenon).  See change (kinêsis); predication; transformation (metabolê) substance (ousia)  centrality to the study of being (to on) vs. centrality to study of causes (aitiai)  10–11, 18–19, 81–82, 152–53 Met. VII 17 discussion of  117–18 See also artifacts; causal profiles; definition; hylomorphism; transformation (metabolê) supervenience  19–20, 175, 180–81, 202, 236, 258 See also non-​causal states of affairs teleological explanation  natural  51, 103, 136, 241–43, 252–53 patterns of  224–25, 234–35, 243 Platonic  4, 52 scope of  10, 127–28, 143–44 See also causal profiles, end-​dominant; causes, final; ‘that for the sake of which’ ‘that for the sake of which’ (hou heneka)  63–64, 224–25 absence of from most of the Meteorology  127–28 two senses of  95–97, 137, 157 See also teleological explanation time, relation to causal laws  195 transeunt-​causal changes.  See acting (poiein) and being-​acted upon (paschein) transformation (metabolê)  generation (genesis) and destruction (phthora) distinguished from change-​ proper (kinêsis)  119–20 irreducibility claims about  37–44 matter as the basis of  37–39, 145, 217 as object of natural-​scientific inquiry  25, 75–76, 107 varieties of  25, 38

Subject Index  287 See also causal profiles; basic “chemical” interactions (from Meteorology IV); change (kinêsis); elements, inter-​transformation of; reductionism transmission theories of causality  97, 153n.38 Tuozzo, T.  172n.20 understanding.  See scientific knowledge (epistêmê)

universals  induction and  206 in Physics I 1  211–12, 253–54 and scientific knowledge  44, 204, 207, 209–10, 226–27, 232 unmoved movers  73, 95–97, 171–72 See also moved movers; change (kinêsis) wisdom (sophia)  1, 199