Existentialism is a term applied to some late 19th- and 20th-century philosophers who may not have agreed about much, but who all believed that each person must define themselves in an absurd, illogical world. The following are the core figures of existentialist philosophy.
Søren Kierkegaard (1813–1855): The Danish son of a wealthy merchant, Kierkegaard never held an academic post, but he wrote voluminously. Seen by many as the founder of existentialism, particularly Christian existentialism.
Key contributions: His analysis of religious experience, and the first developed analysis of many key existential concepts, including absurdity, anguish, authenticity, the weight of responsibility you bear for your choices, and the importance of the irrational to human life
Key works: Either/Or (1843), Fear and Trembling (1843), Concluding Unscientific Postscript (1846), The Sickness Unto Death (1849)
Friedrich Nietzsche (1844–1900): The devout son of a Lutheran minister in Prussia, Nietzsche eventually broke with the church to become one of its staunchest critics and another founding father of existentialism.
Key contributions: Announcing the death of God; changing the human project from that of finding value and meaning to creating value and meaning; returning philosophy to its Greek roots and the concern for the health of the soul
Key works: Human, All too Human (1878–1880), The Gay Science (1882–1887), Thus Spoke Zarathustra (1883–1891), Beyond Good and Evil (1886), The Genealogy of Morals (1887), Ecce Homo (1888)
Martin Heidegger (1889–1976): The most thoroughly academic of the existentialists. His involvement with the Nazi party couldn't stop his magnum opus from being one of the most influential books of the 20th century.
Key contributions: Turning existentialism into the systematic study of existence, particularly of Dasein; developing the concepts of being thrown and the situated subject
Key work: Being and Time (1927)
Jean-Paul Sartre (1905–1980): Heidegger's most celebrated pupil, and the leading French existentialist. Philosopher, novelist, playwright, and political activist, Sartre lived the existential mantra of engagement in the world.
Key contributions: Popularizing existentialism; summarizing the existential perspective in the phrase existence precedes essence; developing existentialism as a philosophy of freedom
Key works: Nausea (1938), Being and Nothingness (1943), No Exit (1943), Existentialism is a Humanism (1947), Anti-Semite and Jew (1947)
Simone de Beauvoir (1908–1986): Seen by some as a mere mouthpiece of Sartre, de Beauvoir was a brilliant thinker in her own right, and she made significant contributions to literature, feminism, and existentialism.
Key contributions: Addressing the problem of other people; the development of a sophisticated existential ethics; grounding much of modern feminism in a largely existential framework
Key works: The Blood of Others (1945), The Ethics of Ambiguity (1947), The Second Sex (1949), The Mandarins (1954)
Albert Camus (1913–1960): In many respects, Camus is the conscience of existentialism. A deeply compassionate man, his philosophy was centered on what he considered the universe's greatest injustice — death. Ironically, he died at a relatively young age.
Key contributions: Writing the greatest and most accessible of all existential novels, The Stranger; developing existentialism as a philosophy of absurdity; infusing existential philosophy with compassion and genuine humanity
Key works: The Myth of Sisyphus (1942), The Stranger (1942), The Plague (1947), The Rebel (1951)