PSYCHOLOGY BY EDWARD L. THORNDIKE NEW YORK 1905 SEP 2905 BI •T39 Р INTRODUCTION I have been invited to contribute a preface to this book, though when I ask myself, why any book from Professor Thorndike's pen should need an introduction to the public by another hand, I find no answer. Both as an experimental investigator, as a critic of other investigators, and as an expounder of results, he stands in the very forefront of American psychologists, and his references to my works in the text that follows will, I am sure, introduce me to more readers than I can introduce him to by my preface. In addition to the monographs which have been pouring from the press for twenty years past, we have by this time, both in English and in German, a very large number of general text-books, some larger and some smaller, but all covering the ground in ways which, so far as students go, are practical equivalents for each other. The main subdivisions, principles, and features of descriptive psychology are at present well made out, and writers are agreed about them. If one has read earlier books, one need not read the very newest one in order to catch up with the progress of the science. The differences in them are largely of order and emphasis, or of fondness on the authors' parts for certain phrases, or for their own modes of approach to particular questions. It is one and the same body of facts with which they all make us acquainted. Some of these treatises indeed give much more prominence to the details of experimentation than others— |