The system with which Freud and his successors have structured the phenomenology of the psychoanalytic experience is made up of words. Ancient words that get tangled up in a renewed way. As a scientist, Freud could admit θεωρία as the measure of reality; as an epistemologist, he clearly envisaged that the scientist's operation does not consist so much in sifting reality as in always approaching it. Placing the scientific vocation of psychoanalysis is to reason on an ethics oriented towards the writing of a real. The Lacanian elaboration on the conceptual limit entailed in the concept itself of unconscious —Unbegriff— is a general epistemological indication, essential to elucidate the status of knowledge in psychoanalysis.