These were the conclusions reached and the ground on which Freudian psychology rested, regarding the etiology of the neurosis, and the tendencies underlying normal human mechanisms, when Dr. Carl Jung, the most prominent of Freud’s disciples, and the leader of the Zurich school, found himself no longer able to agree with Freud’s findings in certain particulars, although the phenomena which Freud observed and the technique of psychoanalysis developed by Freud were the material on which Jung worked and the value of which he clearly emphasizes. The differences which have developed lay in his understanding and interpretation of the phenomena observed. Beginning with the conception of libido itself as a term used to connote sexual hunger and craving, albeit the meaning of the word sexual was extended by Freud to embrace a much wider significance than common usage has assigned it, Jung was unable to confine himself to this limitation. He conceived this longing, this urge or push of life as something extending beyond sexuality even in its wider sense. He saw in the term libido a concept of unknown nature, comparable to Bergson’s élan vital, a hypothetical energy of life, which occupies itself not only in sexuality but in various physiological and psychological manifestations such as growth, development, hunger, and all the human activities and interests. This cosmic energy or urge manifested in the human being he calls libido and compares it with the energy of physics. Although recognizing, in common with Freud as well as with many others, the primal instinct of reproduction as the basis of many functions and present-day activities of mankind no longer sexual in character he repudiates the idea of still calling them sexual, even though their development was a growth originally out of the sexual. Sexuality and its various manifestations Jung sees as most important channels occupied by libido, but not the exclusive ones through which libido flows. This is an energic concept of life; and from this viewpoint this hypothetical energy of life or libido is a living power used instinctively by man in all the automatic processes of his functioning; such very processes being but different manifestations of this energy. By virtue of its quality of mobility and change man, through his understanding and intelligence, has the power consciously to direct and use his libido in definite and desired ways. In this conception of Jung will be seen an analogy to Bergson, who speaks of “this change, this movement and becoming, this self-creation, call it what you will, as the very stuff and reality of our being.”[2] In developing the energic conception of libido and separating it from Freud’s sexual definition, Jung makes possible the explanation of interest in general, and provides a working concept by which not only the specifically sexual, but the general activities and reactions of man can be understood.