Sartre began from a deceptively simple observation about design. A paper-knife exists because a craftsman first conceived its purpose — its essence precedes its existence. For most of Western history, humans were understood the same way: created by God with a given nature and purpose built in. But if there is no such designer, Sartre argued, then for human beings the order reverses. We simply find ourselves existing, without instructions, and only through living do we forge whatever essence we will have. Existence precedes essence.
The consequence is a freedom so total it becomes a burden. We cannot appeal to human nature, to God's plan, or to our upbringing to excuse who we are, because at every moment we are choosing, and could choose otherwise. Sartre called this being 'condemned to be free' — condemned, because we did not ask for this freedom, yet cannot escape it, and are fully responsible for everything we make of ourselves. Even refusing to choose is a choice.
Bad faithThe lie we tell ourselves.
Because this freedom is so heavy, we constantly try to flee it. Sartre called that flight 'bad faith': deceiving ourselves that we are not free, that we are merely playing a fixed role or bound by our circumstances. His famous example is a waiter who throws himself so completely into 'being a waiter' that he pretends the role is his whole identity, hiding from the fact that he freely chooses it each day. Bad faith is comforting precisely because genuine freedom is frightening — but for Sartre it is a betrayal of what we are.
Sartre lived his philosophy publicly. He wrote dense works like Being and Nothingness alongside plays and novels that carried existentialism to a wide audience, and he was, for decades, one of the most famous intellectuals alive, in a lifelong partnership with the philosopher Simone de Beauvoir. In 1964 he declined the Nobel Prize in Literature, unwilling to be turned into an institution. His insistence that meaning is not given but made — that we author ourselves through action — remains existentialism's defining message.