Jean-Paul Sartre

Sartre is the public face of 20th-century existentialism. With Simone de Beauvoir he made the Café de Flore in Paris into a philosophical headquarters; together they refused to marry, kept separate apartments, and remained a famously open intellectual couple for fifty years. He turned down the Nobel Prize in 1964.

His central thesis: for humans, existence precedes essence. You are not first a defined kind of thing (a "human nature") that then acts. You exist, and you make yourself, action by action, choice by choice. This freedom is total and unbearable. To pretend it is not — to act as if your role, your job, your past determined you — is bad faith. The famous waiter who is too much a waiter is Sartre's case study.

His phenomenological ontology, Being and Nothingness, is enormous and uneven and brilliant. His plays and novels (No Exit, Nausea) carried existentialist ideas to a mass audience. Later he became a committed Marxist and a relentless political activist. His unfinished Critique of Dialectical Reason tried to reconcile existential freedom with Marxist history.