 By contrast, Sartre’s own existential psychoanalysis aims to remain faithful to one of the earliest claims of Husserl’s phenomenology: that all psychic acts are “coextensive with consciousness” (Sartre 1943 [1956: 570]). For Sartre, however, the basic motivation for rejecting Freud’s hypothesis is less an inheritance of Brentano’s descriptive psychology (as was the case for Husserl) than a consequence of Sartre’s fundamental critique of determinism, applied to the naturalist presuppositions of empirical psychoanalysis and the particular kind of determinism that it involves. In agreement with Freud, Sartre holds that psychic life remains inevitably “opaque” and at least somewhat impenetrable to us. He also stresses that the philosophical understanding of human reality requires a method for investigating the meaning of psychic facts. But Sartre denies that the methods and causal laws of the natural sciences are of any help in that respect. The human psyche cannot be fully analysed and explained as a mere result of external constraints acting like physical forces or natural causes. The for-itself, being always what it is not and not what it is, remains free whatever the external and social constraints. Sartre is consequently bound to reject any emphasis on the causal impact of the past upon the present, which he argues is the basic methodological framework of empirical psychoanalysis. That does not mean that past psychic or physical facts have no impact on one’s existence whatsoever. Rather, Sartre contends that the impact of past events is determined in relation to one’s present choice, and understood as the consequence of the power invested in this free choice. As he puts it: 