ABSTRACT
In the autumn of 1914 the demands of military service broke in upon the psychoanalytic activities of the author of this work and exiled him to a small garrison town, where he found the duties of chief medical officer to a squadron of Hussars somewhat of a contrast to the pressure of activity to which he had been accustomed. Gradually the conviction grew upon that an importation into psychology of concepts belonging to the field of natural science, and into the natural sciences of psychological concepts, was inevitable and might be extremely fruitful. The physicist is able to make the phenomena of his science comprehensible only when he compares them to "forces", "attraction", "repulsion", to "resistance", "inertia", and the like. Professor Freud was compelled to reduce mental functioning to topographical, dynamic, economic, and therefore purely physical processes, for otherwise he was unable to approach their final explanation.
