Socrates

Socrates wrote nothing and changed philosophy permanently. Born in Athens around 470 BC, the son of a stonemason and a midwife, he served as a hoplite at Potidaea, Delium and Amphipolis, where his conduct under retreat was remarked on, and he lived in poverty, barefoot and indifferent to comfort. Everything known about him comes through others — Plato's dialogues, Xenophon's memoirs and Aristophanes' hostile caricature — and separating the man from Plato's use of him is the standing problem of the subject. His method was interrogation. He claimed to know nothing and to be unable to teach, and asked people who claimed expertise to define what they professed — courage, piety, justice — then exposed the contradictions in their answers. The Delphic oracle had said no one was wiser than Socrates, and he concluded it meant only that he alone knew he was ignorant. He held that virtue is knowledge, that nobody does wrong willingly, that it is better to suffer injustice than to commit it, and that the unexamined life is not worth living. He made enemies. Athens had lost the Peloponnesian War, and two of his associates — Alcibiades and Critias — had betrayed and tyrannised the city. In 399 BC he was tried for impiety and corrupting the young. He refused to plead for mercy, proposed free meals at public expense as his penalty, and was condemned by a narrow margin. He declined to escape, arguing that a citizen who has accepted a city's laws cannot break them when they go against him, and drank hemlock.

• Lived: 470 BCE – 399 BCE
• Nationality: Greek
• Roles: philosopher