"Being and Nothingness" was based on Sartre's interpretion of Heidegger's phenomenology of "Dasein" (being there, one's experience of the present) as "thrown", or random and uncontrollable. Despite the difficulties he was experiencing during this time for his never revoked alignment with National Socialism and the ways in which Sartre's enthusiasm benefitted him, Heidegger felt he had no choice but to denounce Sartre and his views in the essay, "Exisentialism is Not a Humanism" (in direct confrontation with Sartre's apologia "Existentialism is a Humanism"). In the mid 1950s, following Nikita Kruschev's revelation of the actual history of the Soviet Union under Stalin, Sartre's undaunted vamping for the Communist Party was seen by most as grotesque and distasteful. His rationale was that in the face of the meaninglessness of existence, all that mattered was that a decision be made, even if it was absurd. His presence in French media continued but his thought was utterly discredited amongst French philosophers by the time of Michel Foucault's emergence into prominence in the early 1960s. Of course, this was just the time that he was becoming well known and influential in the U.S. This phenomenon is quite familiar and continues. Jacques Derrida has had no credibility in France since the late 1970s but throughout the late 1980s and 1990s his philosophy of Deconstruction and the post-modern (aka Po-Mo) marginal was tremendously influential. It is perhaps to blame for the bloat of Cultural Studies prevalent in American academia.

Nonetheless, Sarte's relationship with Simone de Beauvoir earns him a bit of a place in 20th century history.