A good many years of experience in teaching the history of philosophy to beginners have convinced me that students come to the subject with four classes of ideas, with which they can correlate philosophic doctrines: good geographical knowledge, some historical and some literary knowledge, and many undefined personal philosophical opinions. Of course, their personal philosophical opinions form the most important group, but more as something to be clarified by the civilizing influence of the subject than as an approach to the subject itself. The only “memory-hooks” upon which the teacher may expect to hang philosophic doctrines are the student’s ideas of history, literature, and geography. If the history of philosophy is treated only as a series of doctrines, the student beginning the subject feels not only that the land is strange, but that he is a stranger in it. Besides, to isolate the historical philosophical doctrines is to give the student a wrong historical perspective, since philosophic thought and contemporary events are two inseparable aspects of history. Each interprets the other, and neither can be correctly understood without the other. If the history of philosophy is to have any significance for the beginner, it must be shown to give a meaning to history. So far as the materials that form any history of philosophy are concerned, I have merely tried to arrange and organize them with reference to the student and with reference to the history of which they form an integral part. I am therefore overwhelmingly indebted to every good authority to whom I have had access, but in the main I have followed the inspiring direction of the great Windelband. Many willing friends have read parts of the manuscript and offered suggestions and criticisms. I am particularly indebted to Professors C. P. Parker, Ephraim Emerton, A. O. Norton, and J. H. Ropes, and Dr. B. A. G. Fuller of Harvard University; to Professor Mary W. Calkins of Wellesley College; to Professors C. S. Wade and D. L. Maulsby of Tufts College; and to my wife, Abby B. Cushman. However, for all the faults of the book, which has been many years in preparation, I am alone responsible. Instead of lists of books for collateral reading, placed at the end of chapters or of the book, the student will find references in the footnotes to the exact pages of many helpful books. I should like to call the student’s attention to an appendix to the discussion of Plato. This is a complete selection of passages from Plato made by the late Professor Jowett for English readers. This selection Professor Jowett was accustomed to distribute to his Oxford class, of which I was once fortunate to be a member. Philosophical terms have been defined either in the text or in the footnotes. Such definitions must necessarily have as their aim their usefulness to the student, rather than their completeness. TUFTS COLLEGE, June, 1910. PREFACE TO THE REVISED EDITION