_Fourth_, further study of our drives increases the certainty of their enormous plasticity. Woodworth has maintained that any mental mechanism can become a drive, that is, that we can develop a positive interest in and tendency to repeat anything that we ever do--we can “take an interest” in anything. Watson, too, from his point of view, and with his own conception of the method, holds that a man can acquire practically any qualities. “Condition” the few original reflexes in appropriate manner, and you will make of an individual a religious devotee, a monster of vice, or what you will. Finally, the whole notion that we possess an equipment of just such and so many instincts is threatened, not only from the Watsonian angle but also from several others. Instincts, various writers point out, appear to be classificatory devices and nothing more. For our present purpose it is not essential to forecast the ultimate outcome of researches that bear upon these points. It is sufficient to recognize the great range of human motivation, the great plasticity of it (that is, the indefinitely many possibilities of character for the same individual), and the organic character of it (that is, the capacity for action from the standpoint of a desired whole). Anyone who is interested in the future development of thought upon this matter will do well to watch the discussions of the concept of “organism” (Whitehead’s term) in the physical sciences and of “configuration” (an English translation of the German, _Gestalt_, as used by Koffka) or an equivalent in psychology. The physics of today already has transcended the notion that bodies are aggregates of elements--transcended it, not upon speculative or metaphysical grounds alone, but also upon the basis of experiment and mathematical analysis. Throughout nature, so Whitehead says, any concrete actuality is a dynamic whole, a complex event, not a corpuscle or an aggregate of corpuscles. These are merely abstractions, useful in their way, but matter is not even the residence of energy. Further, these dynamic wholes act spontaneously, and they even transform themselves from within themselves--they do not wait to be acted upon like billiard balls; rather, initiative is everywhere present. If this conception of physical nature should become the accepted view, it would remove at a stroke the methodological foundation of much psychology that regards itself as particularly entitled to be called scientific. In particular, the whole of psychology would become dynamic psychology, and motivation would be recognized as _in limine_ both organizing and self-transforming action. It is a safe guess that, in this case, _the self_ would be accorded a far less grudging place than it has had in the psychology of the last generation. Professor Calkins has recently pointed out, in fact, that several contemporary movements of psychology are converging in this general direction.