Simone de Beauvoir (1908–1986) joins existentialist ideas about freedom with an analysis of how freedom is constrained and shaped by embodied, social, economic, and historical situations.

Big idea: Human beings become themselves through choices, but nobody chooses from nowhere. Freedom is real and ethically important while always exercised inside conditions we did not choose.

In The Second Sex (1949), Beauvoir's famous claim that one is not born but rather becomes a woman targets the idea that women's social roles and possibilities follow automatically from biological sex. She analyzes how culture constructs woman as Other relative to man as default Subject.

This is not the claim that bodies are unreal or irrelevant. Beauvoir repeatedly examines embodiment, reproduction, sexuality, work, economic dependence, myth, and social institutions. The point is that biology does not by itself dictate the meanings and destinies societies build around it.

Her ethics also resists a cartoon version of existentialism as “do whatever you choose.” Because our freedom is intertwined with other people's freedom, treating others merely as objects undermines the shared conditions in which meaningful freedom exists.

Beauvoir's philosophical importance was for years obscured by treating her primarily as Sartre's companion or applying Sartre's framework to her work. Contemporary scholarship treats her as a major philosopher in her own right.