What is Existentialism Is a Humanism about?

Existentialism Is a Humanism began as a 1945 lecture Sartre gave to a packed Paris hall in response to critics who called existentialism pessimistic, quietist, and dangerous. The text is Sartre's most accessible statement of his philosophy — short, clear, and rhetorically sharp in a way that Being and Nothingness never is. He was later ambivalent about it, feeling it oversimplified his position, but it remains the standard entry point into existentialist thought.

The core argument turns on three formulations. First, existence precedes essence: for human beings, unlike artifacts designed before they are made, there is no pre-given nature or purpose. We exist first, then create ourselves through choice. Second, because there is no fixed human nature and no God to provide a blueprint, radical freedom is not optional — we are fully responsible for what we become. Third, this responsibility extends beyond the individual: in choosing for yourself, you implicitly choose for all of humanity, because you are affirming a vision of what humans should be. Bad faith — the refusal to own this responsibility — is always possible but never exculpatory.

Sartre addresses several standard objections. If existentialism denies human nature, how can it provide moral guidance? His answer is that freedom is the only value that grounds all other values, and that refusing to acknowledge one's freedom is the one genuine moral failure. Against the charge of quietism, he argues that the anguish of freedom does not paralyze but demands: once you accept that you are fully responsible, you cannot defer to God, tradition, or circumstance.

The lecture ends with a rejoinder to Marxist critics who felt existentialism was too individualistic. Sartre argues that it is in fact a humanism precisely because it places the entire burden of the human condition on human beings, without external support. Whether that constitutes genuine humanism or a new form of isolation remains a live question in the literature, and Sartre himself would substantially revise his position in the Critique of Dialectical Reason fifteen years later.