In the late 19th century, when Freud initially realized that the identification between mind and consciousness could not account for a series of psychic phenomena, psychology was the project for a science of consciousness yet. The programs for a scientific psychology emerging at that time, such as Brentano's, Wundt's and James', sustained the identity of mind and consciousness and regarded the existence of unconscious mental processes as a factual and theoretical impossibility. Firstly, this paper sets out to discuss Freud's strategy to formulate the hypothesis of an unconscious psychical in his metapsychological theory. Next, it examines the justification of this hypothesis, following the systematic reconstruction of Freud's argument suggested by J. Wakefield (1992). Lastly, it briefly comments on the relationship between conscious and unconscious psychic processes, such as it is presented in Freudian metapsychology, stressing how this relationship turns out to be one of its greatest theoretical difficulties.
Freud; Metapsychology; Unconscious; Consciousness; Brain processes