Table of contents : Introduction I. Logic as a science (I) II. Logic as a science (II) Part I. The logic of concepts I. Concepts and abstraction II. The universality of concepts and the singularity of real beings III. Language as the expression of thought IV. The analogical meaning of concepts V. Predicables, the logical modes of the universals VI. Definition, division and opposition of concepts Part II. The logic of the proposition I. The proposition in general II. Kinds of propositions Part III. The logic of reasoning I. General characteristic of reasoning II. Analysis of reasoning: the syllogism III. Induction IV. Fallacies Part IV. Scientific Knowledge I. Nature and object of scientific knowledge II. Philosophy and the particular sciences III. Order of the sciences IV. The scientific method V. The principles of scientific knowledge