Martin Heidegger

Heidegger reframed the oldest question in philosophy — what is Being? — and argued that 2,500 years of metaphysics had forgotten how to ask it. His Being and Time (1927) proposes that we are not, in the first place, subjects standing apart from a world of objects. We are Dasein — "being-there" — always already thrown into a world of meaningful things, projects, anxieties. We exist toward our own death, and authentic existence is the resolute facing of this finitude.

His prose is famously hard, partly because German is an accordion and partly because he believed ordinary philosophical language could not say what he wanted. He invented vocabulary: Geworfenheit (thrownness), Zuhandenheit (ready-to-hand), Sein-zum-Tode (being-toward-death).

His joining of the Nazi party in 1933, his rectorship at Freiburg, and his lifelong refusal to apologize remain the most disturbing moral question in modern philosophy. The work and the life cannot be separated; both must be reckoned with. He nonetheless reshaped continental philosophy, theology, hermeneutics, and architecture. Existentialism, in its 20th-century form, begins with him.