Now, as a matter of fact, there are a large number of phenomena which not only justify the postulation of subconscious processes but also the inference that such processes, activated by their affective impulses, may so influence conscious thought that the latter is modified in various ways; that it may be determined in this or that direction, inhibited, interrupted, distorted, made insistent, and given pathological traits. There is also a large variety of bodily phenomena which can be explicitly shown to be due to subconscious processes, and many which are only explicable by such a mechanism. Indeed, a subconscious process may become very complex and constellated with any one or many of the psycho-physiological mechanisms of the organism. In special artificial and pathological conditions where such processes reach their highest development, as manifested through their phenomena, they may exhibit that which when consciously performed is understood to be _intelligence_, comprising reasoning, constructive imagination, volition, and feeling; in short, what is commonly called thought or mental processes. Memory, of course, enters as an intrinsic element in these manifestations just as it is an intrinsic element in all thought. The automatic script that describes the memories of a long-forgotten childhood experience may at the same time reason, indulge in jests, rhyme, express cognition and understanding of questions—indeed (if put to the test), might not only pass a Binet-Simon examination for intelligence, but take a high rank in a Civil Service examination. In these more elaborate exhibitions of subconscious intelligence it is obvious that there is an exuberant efflorescence of the residua deposited in many unconscious fields by life’s experiences and synthesized into a _subconscious functioning system_. It is beyond the scope of this lecture to examine into the particular _mechanism_ by which a subconscious process is provoked at all—why, for instance, a dormant wish or fear-neurogram becomes activated into a subconscious wish or fear, or having become activated, the mechanism by which such a wish or fear manifests itself in this phenomenon or that—or to examine even any large number of the various phenomena which are provoked by subconscious processes, and it is not my intention to do so. Such problems belong to special psychology and special pathology. Of recent years, for instance, certain schools of psychology, and in particular the Freudian school, have attempted to establish particular mechanisms by which subconscious processes come into being and express themselves. We are engaged in the preliminary and fundamental task of establishing, if possible, certain basic principles which any mechanism must make use of, and, as a deeper-lying theoretical question, the nature of such processes.