2. Dramatic imitation in play 300 3. Plastic or constructive imitative play 313 4. Inner imitation 322 IV. SOCIAL PLAY 334 PART III _THE THEORY Of PLAY_ 1. The physiological standpoint 361 2. The biological standpoint 369 3. The psychological standpoint 379 4. The æsthetic standpoint 389 5. The sociological standpoint 395 6. The pedagogical standpoint 398 INDEX 407 THE PLAY OF MAN THE SYSTEM OF PLAY INTRODUCTION While many have undertaken, by various methods, to classify human play satisfactorily, in no single case has the result been entirely fortunate. Grasberger remarked, a quarter of a century ago, that a permanent classification of play had not up to that time been achieved,[1] and in my opinion the present decade finds the situation essentially unchanged. Under these circumstances, I can hardly hope that my own classification will satisfy all demands, but I reassure myself with the reflection that absolute systematization is and must remain, in the vast majority of cases, a mere logical ideal. Yet even an imperfect classification may justify itself in two ways: it may be very comprehensive and practical, or its aptly chosen grounds of distinction may serve to open at once to the reader the inmost core of the subject under discussion. My special effort has been directed to the second of these uses, adopting as I do the conception of impulse life as a starting point; how far I may have attained to the first as well is for others to judge. I consider the governing force of instinct as having been fully established in the study of animal play. In the book[2] which deals with this subject I reached the conclusion that among higher animals certain instincts are present which, especially in youth, but also in maturity, produce activity that is without serious intent, and so give rise to the various phenomena which we include in the word “play.” I shall treat of the biological significance of this fact in the second, the theoretical section of this book. Here I confine myself to remarking briefly that in child’s play (which, according to one theory of our subject, is of the utmost importance) opportunity is given to the animal, through the exercise of inborn dispositions, to strengthen and increase his inheritance in the acquisition of adaptations to his complicated environment, an achievement which would be unattainable by mere mechanical instinct alone. The fact that youth is _par excellence_ the period of play is in thorough harmony with this theory.