COPYRIGHT, 1923, BY HARCOURT, BRACE AND COMPANY, INC. PRINTED IN THE U.S.A. PREFACE In the essays gathered together in this volume we have the most developed and coherent available account of the philosophy of Charles S. Peirce, whom James, Royce, Dewey, and leading thinkers in England, France, Germany and Italy have placed in the forefront of the great seminal minds of recent times. Besides their inherent value as the expression of a highly original and fruitful mind, unusually well trained and informed in the exact sciences, these essays are also important as giving us the sources of a great deal of contemporary American philosophy. Because of this historical importance no omissions or changes have been made in the text beyond the correction of some obvious slips and the recasting of a few expressions in the interest of intelligibility. In a subject which bristles with suggestions and difficulties the temptation to add notes of explanation or dissent is almost insuperable. But as such notes might easily have doubled the size of this volume I have refrained from all comment on the text except in a few footnotes (indicated, as usual, in brackets). The introduction is intended (and I hope it will) help the reader to concatenate the various lines of thought contained in these essays. I cannot pretend to have adequately indicated their significance. Great minds like those of James and Royce have been nourished by these writings and I am persuaded that they still offer mines of fruitful suggestion. Prof. Dewey’s supplementary essay indicates their value for the fundamental question of metaphysics, viz. the nature of reality. Grateful acknowledgment is here made to Mrs. Paul Carus and to the Open Court Publishing Co. for permission to reprint the essays of Part II from the _Monist_. The late Paul Carus was one of the very few who not only gave Peirce an opportunity to publish, but publicly recognized the importance of his writings. I must also acknowledge my obligation to Professor Dewey for kind permission to reprint his essay on the Pragmatism of Peirce from the Journal of Philosophy, and to the editors of that Journal, Professors Woodbridge and Bush, for permission to reprint some material of my own. Part V of the Bibliography was compiled by Mr. Irving Smith. MORRIS R. COHEN THE COLLEGE OF THE CITY OF NEW YORK. TABLE OF CONTENTS INTRODUCTION vii PROEM. THE RULES OF PHILOSOPHY 1 PART I. CHANCE AND LOGIC (Illustrations of the Logic of Science.) 1. The Fixation of Belief 7 2. How to Make Our Ideas Clear 32 3. The Doctrine of Chances 61 4. The Probability of Induction 82 5. The Order of Nature 106 6. Deduction, Induction and Hypothesis 131 PART II. LOVE AND CHANCE 1. The Architecture of Theories 157 2. The Doctrine of Necessity Examined 179 3. The Law of Mind 202