Psychoanalysis could only establish itself once the barriers that philosophy and psychology had erected on the boundaries between the body and the soul, the normal and the pathological, the conscious and the unconscious, had been removed. On this point, it was the discovery of the work of Theodor Lipps and his critique of the phenomenology of Franz Brentano that enabled Freud to open up a new path of access to the question of the unconscious, which his former mentor had blocked. However, the unconscious he revealed had little to do with Lipps’ doctrine. Freud therefore drew attention several times to the theoretical conditions that had made his creation possible, inviting us to think of it in terms of a bifurcation. This can be seen as an invitation to consider the history of psychoanalysis as a whole in this way.