The first of these displeasing assertions of psychoanalysis is this, that the psychic processes are in themselves unconscious, and that those which are conscious are merely isolated acts and parts of the total psychic life. Recollect that we are, on the contrary, accustomed to identify the psychic with the conscious. Consciousness actually means for us the distinguishing characteristic of the psychic life, and psychology is the science of the content of consciousness. Indeed, so obvious does this identification seem to us that we consider its slightest contradiction obvious nonsense, and yet psychoanalysis cannot avoid raising this contradiction; it cannot accept the identity of the conscious with the psychic. Its definition of the psychic affirms that they are processes of the nature of feeling, thinking, willing; and it must assert that there is such a thing as unconscious thinking and unconscious willing. But with this assertion psychoanalysis has alienated, to start with, the sympathy of all friends of sober science, and has laid itself open to the suspicion of being a fantastic mystery study which would build in darkness and fish in murky waters. You, however, ladies and gentlemen, naturally cannot as yet understand what justification I have for stigmatizing as a prejudice so abstract a phrase as this one, that "the psychic is consciousness." You cannot know what evaluation can have led to the denial of the unconscious, if such a thing really exists, and what advantage may have resulted from this denial. It sounds like a mere argument over words whether one shall say that the psychic coincides with the conscious or whether one shall extend it beyond that, and yet I can assure you that by the acceptance of unconscious processes you have paved the way for a decisively new orientation in the world and in science.
Just as little can you guess how intimate a connection this initial boldness of psychoanalysis has with the one which follows. The next assertion which psychoanalysis proclaims as one of its discoveries, affirms that those instinctive impulses which one can only call sexual in the narrower as well as in the wider sense, play an uncommonly large role in the causation of nervous and mental diseases, and that those impulses are a causation which has never been adequately appreciated. Nay, indeed, psychoanalysis claims that these same sexual impulses have made contributions whose value cannot be overestimated to the highest cultural, artistic and social achievements of the human mind.