To explain any matter is to discover the points of similarity, or virtual identity, between the matter studied and ourselves. But in order to do this thoroughly, or rather in order to do it with relation to the essential nature of some form of energy (the "Libido," for example, considered as an unpicturable force) one must first consider what we, the investigators, are, not at our less good, but at our best. It is with us, as given, with our best qualities regarded as defining in part the Q. E. D. of the experiment, that the investigation must begin. The nature of any and every form of real underlying energy or essence must be defined in terms of our sense of our own will and freedom. And this means that we must conceive and describe ourselves, and expect to conceive and to describe the powers that animate us, no longer as a system of forces subject to the so-called laws of nature (which are, in reality, not immutable) but as relatively free, creative agents; no longer as the product of the interplay of instincts, but as individuals possessed of real reason, real power of love and real self-consistent will. To claim to study the effects of the "Libido," to which we ascribe the vast powers with which we are familiar, yet fail to seek in it what would correspond to our own best attributes, would be to lay aside our duties as students of human nature. It would be to confine our attention to the "structure" of the mind, the form under which it manifests itself, without having studied the laws of its action under conditions which are more favorable to its development. It must, now, have struck students of psychoanalytic literature that a marked tendency has been shown toward supplementing the study of structure,--that is, the detailed history of men's experiences and evolution, regarded as sequences of phenomena,--by the study of the function or creative energy for which the experiences stand. Silberer, whose work is endorsed by Freud, has gone to a considerable length in this direction; and the whole tendency of Freud's insistence on the relevancy, in the mental sphere, of the law of the conservation of energy has been a movement, though, I think, a narrow one, in this direction. More recently, Jung has emphasized the importance of this tendency, and has dwelt more strongly, as I think, than the facts warrant, on the supposed unwillingness of Freud to recognize its importance. Behind the experiences of childhood, for example, lie the temperamental trends of childhood, and it is these with which we really need to get acquainted; for these trends, if not the whole causes and equivalents of the experiences which are recounted to us by our patients, constitute the conditions without which the latter would not have been what they became.