Epistemology after Protagoras 2004024136, 0199262225

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Epistemology after Protagoras: Responses to Relativism in Plato, Aristotle, and Democritus

MI-KYOUNG LEE

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Great Clarendon Street, Oxford OX2 6DP 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 in Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offices in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan South Korea Poland Portugal Singapore Switzerland Thailand Turkey Ukraine Vietnam Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries Published in the United States by Oxford University Press Inc., New York ,.e Mi-Kyoung Lee, 2005 The moral rights of the author have been asserted Database right Oxford University Press (maker) First published 2005 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, or under terms agreed with the appropriate reprographics rights organization. Enquiries 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 book in any other binding or cover and you must impose this same condition on any acquirer British Library Cataloguing in Publication Data Data available Library of Congress Cataloging in Publication Data

Lee, Mi-Kyoung. Epistemology after Protagoras : responses to relativism in Plato, Aristotle, and Democritus I Mi-Kyoung Lee. p. cm. Includes bibliographical references and index. 1. Protagoras. Aletheia. 2. Relativity-History. 3. Plato. Theaetetus. 4. Aristotle. Metaphysics. Book 4, 5. 5. Democritus. I. Title. B305.P83A44 2005 121'.092-dc22 2004024136 ISBN 0-19-926222-5 I 3 5 7 9 10 8 6 4 2 Typeset by Newgen Imaging Systems (P)Ltd., Chennai, India Printed in Great Britain on acid-free paper by Biddies Ltd., King's Lynn, Norfolk

For PETER

PREFACE AND ACKNOWLEDGEMENTS This book was originally inspired by a question: did philosophical scepticism arise de novo in the Hellenistic period with the Academics and the Pyrrhonists, as is commonly thought, or could elements of scepticism be found earlier in the classical period? Were Plato and Aristotle simply unaware (or dismissive) of scepticism as a serious challenge to their own more optimistic views of the possibility of acquiring knowledge? I found that Protagoras' arguments, as presented and developed in Plato's Theaetetus, and Aristotle's related discussion of Protagoras in Metaphysics r, anticipate in striking ways some of the attacks which Hellenistic sceptics used. Furthermore, Plato's and Aristotle's cases against Protagoras constitute a powerful defence against the sorts of arguments that the Hellenistic sceptics would eventually deploy. My goal in this book, therefore, has been to explore and arrive at a better understanding of the impact of Protagoras' relativist arguments, together with Plato's, Aristotle's, and Democritus' responses to those arguments, on the development of classical Greek epistemology. Much of the material for this book grew out of work I did in graduate seminars given by Gisela Striker, who also taught me as an undergraduate at Columbia University and supervised my Ph.D. dissertation at Harvard Uni­ versity. In addition, her published work on Hellenistic scepticism and on the sophists inspired many of the leading questions and ideas in this book. It is through countless discussions, and many invaluable criticisms and suggestions, that she helped me shape this material into a book. I could not have hoped for a better teacher and adviser. I am also grateful to the following people for their generous and helpful comments on drafts of various chapters: Chloe Balla, Patricia Curd, Gail Fine, W. D. Hart, Rachana Kamtekar, Kathrin Koslicki, Connie Meinwald, Dana Miller, Stephen Menn, Susan Sauve Meyer, Lije Millgram, Ian Mueller, Hilary Putnam, David Sedley, and Angela Smith. Although I sometimes end up dis­ agreeing with him, I-and all scholars-am greatly indebted to Myles Burnyeat for his work on the Theaetetus. I have also benefited from conversations with him and his seminar on the De Anima at Harvard in the autumn of 1991. I thank Pat Curd for showing me part of her forthcoming commentary on Anaxagoras. I also thank J 0rgen Mejer for helpful discussions of Democritus and Diogenes Laertius. Three anonymous readers for Oxford University Press carefully read and commented on successive drafts of this book; their meticulous comments and tough criticisms helped me enormously to get this book into shape. I would

Vlll

Preface and Acknowledgements

like to thank my editor, Peter Momtchiloff, for his advice and encouragement, Jacqueline Baker and Rebecca Bryant of OUP, and my copy-editor, Nigel Hope, for all their help with the book. I also thank It1r Gi.ine� for help with the proofs. None of these people should be blamed for the errors and lapses of judgement which still remain. I thank the Senior Fellows of the Center for Hellenic Studies in Washington DC and its former directors, Deborah Boedeker and Kurt Raaflaub, for giving me the opportunity to work on this book in the splendid library and environ­ ment of the Center for a year. I also acknowledge the support of the National Endowment for the Humanities Summer Stipend for the writing of this book. My colleagues at the Department of Philosophy at the University of Illinois at Chicago, especially Connie Meinwald and Bill Hart, have been incredibly sup­ portive, both by reading my work and by shielding me from the more time­ consuming duties in the department. I am grateful to my parents, Hye-Sook and Joon Chang Lee, and to my sister, Sue Lee, for their unwavering support throughout all the years I have worked on this project. And finally, for all of his advice, comments on drafts, and encouragement, I thank my husband Peter Hunt, to whom I dedicate this book. Chapter 3 is a revised and expanded version of 'The Secret Doctrine: Plato's Defense of Protagoras in the Theaetetus', Oxford Studies in Ancient Philosophy (ed. David Sedley), 19 (Winter 2000), 47-86. Reprinted, with revisions, by permission of Oxford University Press. Chapter 5 is a revised and expanded version of 'Thinking and Perception in Plato's Theaetetus', in Mark McPherran (ed.), Recognition, Remembrance, and Reality: New Essays on Plato's Epistemology and Metaphysics, Apeiron 32/4 (Dec. 1999), 37-54. Reprinted, with revisions, by permission of Academic Publishing and Printing.

CONTENTS List of Abbreviations

Xl

1

Introduction

2

Protagoras' Aletheia 2.1. Introduction 2.2. Protagoras' arguments for the measure doctrine 2.3. What else was in the Aletheia?

8 8 12 21

3

Protagoras and relativism

30 30 34 35 41

3. 1. 3.2. 3.3. 3. 4. 4

Self-refutation and contradiction 4.1. 4.2. 4.3. 4. 4. 4. 5. 4.6.

5

Relativism about truth and infallibilism The history of the idea of relative truth The idea of a measure Protagoras and relative truth

Introduction Plato's arguments against Protagoras Aristotle on Protagoras and contradiction The principle of non-contradiction Protagoras and the principle of non-contradiction Appendix on OVK EaTLV avTLAEyHv

The Secret Doctrine in Plato's Theaetetus 5. 1. 5. 2. 5.3. 5. 4. 5. 5. 5. 6. 5. 7. 5. 8. 5. 9.

Introduction Protagoras and the Secret Doctrine The Secret Doctrine: a sketch Constructing the Secret Doctrine ( Theaetetus 153-160) Stage I (153d8-154b6) Stage II (154b6-155d5) Stage III (155d5-157c3) Stage IV (157c4-160e5) Does the Secret Doctrine work?

1

46 46 47 57 59 64 72 77 77 82 86 93 95 100 104 109 111

Contents

X

6 Aristotle on Protagoras and the Theaetetus 6. 1. Introduction 6.2. The main theme of Metaphysics rs 6.3. Ring structure 6.4. For and against Contradictionism (1009a 22-38) 6.5. Scepticism ( 1009b 33-l 0 103 15) 6.6. Arguments against the doctrine of flux 7

Aristotle on Protagoras and early conceptions of thinking and perceiving 7. 1. 7.2. 7.3. 7.4. 7.5. 7.6. 7.7. 7.8. 7. 9. 7. 10.

8

9

10

Introduction All appearances are true A Protagorean model of thinking Like-by-like theories of alteration and affection The Secret Doctrine theory of perception Plato on why perceiving and thinking are distinct Problems with Protagoras More arguments against Protagoras Only what can be perceived exists Conclusion

Democritus on appearances and perception: the early sources 8. 1. Introduction to Democritus 8.2. Aristotle: Democritus on appearances 8.3. Theophrastus on Democritus

118 118 120 122 123 126 130 133 133 134 136 148 152 154 158 168 177 179 181 181 189 200

Democritus on knowledge and the senses: the late sources 9. 1. Introduction 9.2. Sextus Empiricus 9.3. Democritus the sceptic 9.4. Galen and the senses' reply 9.5. Looking ahead and back: Democritus, Epicurus, and Protagoras

217 217 218 238 242

Conclusion

251

Bibliography Index Locorum General Index

247

255 276 288

LIST OF ABBREVIATIONS

A B DA DK DL DS EN GC KRS LS M Met. OT PH Prat. Rep. ROT SE Soph. Tht. T

Testimonium in Diels-Kranz Fragment in Diels-Kranz Aristotle, De Anima Diels-Kranz, Die Fragmente der Vorsokratiker Diogenes Laertius, Lives of the Philosophers Theophrastus, De Sensibus Aristotle, Ethica Nicomachea Aristotle, De Generatione et Corruptione Kirk, Raven, and Schofield Long and Sedley, The Hellenistic philosophers Sextus Empiricus, Against the Professors [Adversus Mathematicos] Aristotle, Metaphysics Aristotle, Oxford Translation, ed. W. D. Ross Sextus Empiricus, Outlines of Pyrrhonism [Pyrrhoneae hypotyposes] Plato, Protagoras Plato, Republic Aristotle, Revised Oxford Translation, ed. Jonathan Barnes Sextus Empiricus Plato, Sophist Plato, Theaetetus Fragments and Testimonia in Taylor 1999a

Unless otherwise indicated, translations of Plato's Theaetetus come from the Levett/ Burnyeat translation (Hackett, 1990), except in §§5.4-8, where J. McDowell's translation ( Oxford, 1973) has been used. For passages from the other Platonic dialogues, the translations in Plato: Complete Works, ed. J.M. Cooper (Hackett, 1997) have been used. For Aristotle's Metaphysics, Ross' 1928 Oxford translation of the Metaphysics has been used. For the Democritean fragments and testimonia I have used C. C. W. Taylor's translation (Toronto, 1999).

1 Introduction In the Hellenistic period of Greek philosophy, the lines between philosophical camps on the question of whether and how knowledge can be acquired are clearly drawn. We find self-proclaimed sceptics, such as the Academics and Pyrrhonists, posing a forceful challenge to their 'dogmatic, opponents, compelling them to justify their confidence in the very possibility of knowledge. Their opponents counter this in turn by formulating their theories of knowledge as proposals concerning a criterion of truth, that is, a self-evident, infallible measure of the truth that can be used to distinguish with certainty between true and false assertions and thus secure the foundations of knowledge. However, before the Hellenistic era, worries about whether knowledge is really possible seem curiously absent. Certainly expressions of the difficulty of attaining knowledge go back to the earliest Greek thinkers. And in the classical period, Plato addresses the question of what knowledge must be like and how one should go about looking for it in his principal epistemological doctrines, such as his theory of recollection, and in his educational programme predicated on the existence of Forms as the proper object of knowledge. He thinks that acquiring knowledge is extremely difficult, and that most people do not have real knowledge; Socrates in the Republic denies that he has any such knowledge himself. But Plato, like his predecessors, seems to assume that it is possible, at least in principle, to acquire knowledge and discover the truth. This then raises the question: did scepticism only first arise in the Hellenistic period? Or was it already around, in the air, in the classical period? Were Plato, Aristotle, and other philosophers of the classical period simply unaware of scepticism as a problem, confident that philosophical knowledge can be reached, though no doubt with difficulty? Or did they recognize and grapple with some of the ideas and arguments that would later be marshalled for the sceptical position? The aim of this book is to describe and investigate the development of epistemology in the classical period of ancient Greece, focusing on the figures of Protagoras, Plato, Aristotle, and Democritus. My thesis is that scepticism was in the air-not in the form of a well-defined school of thought or position, but in the form of certain loosely related ideas and arguments. Some of these were articulated by Protagoras in his book Aletheia CTruth'), which began with the striking claim that 'Man is the measure of all things, of what is that it is,

2

Introduction

of what is not that it is not. , One might wonder whether this is really