The ambivalent relations between philosophy and psychoanalysis can be noted throughout Freud’s work and are explored here on the basis of an interpretation of Freud’s philosophical references to Kant. The aim is to show how the two approaches complement each other in the development of a theory of thought. Phenomenology makes it possible to go beyond the empiricist and intellectualist interpretations of Freudian metapsychology by giving precedence to an antepredicative experience of the world. But it falls short of Freud’s discovery of the unconscious, which presupposes the repression of this primordial feeling. Furthermore, the discovery of the timelessness of the unconscious determines a non-linear and relative conception of space and time, as evidenced by the dimension of après-coup, and is therefore closer to the conception of quantum physics, in contrast to Kant, whose objective was to secure the theoretical foundations of Newtonian physics and an absolute space-time.