20th-century European movement holding that existence precedes essence — humans first exist, then define themselves through choice. Meaning is not given; it must be made in the face of an indifferent or absurd universe.
Key tenets
Existence precedes essence (Sartre).
Radical freedom and the inescapable responsibility it brings.
Authenticity vs. bad faith / inauthenticity.
The Absurd — the gap between our craving for meaning and the world’s silence.