Antisthenes

Antisthenes was born around 446 BC in Athens to an Athenian father and a Thracian (or Phrygian) mother. The mixed heritage brought lifelong taunts of being not a true Athenian; he answered that the mother of the gods was Phrygian.

He studied rhetoric under Gorgias, then walked nine kilometres daily from Piraeus to Athens to hear Socrates, pulling friends along. He fought at Tanagra around 426 BC, was present at Socrates's death in 399, and helped procure the punishment of those who engineered the trial.

After Socrates's death he founded his school at the Cynosarges, a gymnasium outside Athens for citizens of mixed parentage and open to the poor. He wore a worn cloak as his only undergarment, carried staff and wallet, and lived austerely. This costume became the uniform of his followers; his nickname haplokuon, the dog absolute, captured the style. Through Diogenes and Crates the dress passed to Zeno and became Stoic.

Four propositions sit at the centre of his philosophy. First, virtue can be taught. Second, virtue alone suffices for happiness. Third, virtue is a matter of deeds, not words. Fourth, the wise are self-sufficient (autarkeia). Wealth, reputation, and pleasure were all external and unreliable; only inner virtue could be relied on. Marcus Aurelius quotes him in Meditations 7.36 — to do good and be ill-spoken of is kingly — confirming the line of transmission from Antisthenes into Stoicism.

His writings filled ten volumes, but only fragments survive with two declamations, Ajax and Odysseus. In logic he was a strict nominalist: I see a horse, but I do not see horsehood. This put him in direct conflict with Plato; the rivalry was well known in antiquity.

Whether Diogenes of Sinope studied under him is disputed; some argue the Stoics invented the lineage. Either way, the line of influence — the ascetic life, virtue alone as good, the autarkeia ideal — runs into Stoicism and forms the spine of Hellenistic ethics. He died in Athens around 366 BC.