Jean-Paul Sartre

French existentialist philosopher and writer — author of Being and Nothingness, Existentialism is a Humanism, and Nausea — Nobel Prize in Literature (refused, 1964) — who created the secular existentialism philosophy and whose 'existence precedes essence' is the defining existentialist formula.

Creates secular existentialism — Sartre's argument (that humans first exist, then choose their essence — that there is no human nature that precedes individual choice) is the most influential statement of secular existentialism and of radical human freedom and responsibility.