Xenocrates led Plato's Academy yet refused to become an Athenian citizen
Offered Athenian citizenship as thanks for negotiating peace with Macedon, Xenocrates turned it down: the deal had stripped thousands of poor Athenians of their vote. As head of Plato's Academy he gave Platonism a firmer, more mathematical shape, teaching that the soul is a number that moves itself.
Born in Chalcedon around 396/5 BC, Xenocrates came to Athens young, studied first under Aeschines Socraticus and then attached himself to Plato, going with him to Sicily in 361. After Plato died he travelled with Aristotle to visit Hermias of Atarneus. In 339/8 BC he narrowly won the vote to succeed Speusippus as scholarch, beating Heraclides Ponticus and Menedemus by only a few ballots.
Contemporaries found him socially awkward but steady, thorough and scrupulously honest, and Athens trusted him with embassies, once to Philip of Macedon and twice to Antipater. He disliked Macedonian power in the city. When peace with Antipater came at the cost of a narrower constitution, he declined the citizenship pressed on him through Phocion. Too poor to pay the tax on resident foreigners, he is said to have been rescued by the orator Lycurgus, or even purchased by Demetrius Phalereus and set free.
As a thinker he systematised rather than questioned. He sharpened the split of philosophy into physics, dialectic and ethics, and dropped Plato's habit of working through puzzles in favour of stating doctrine outright. He ranked knowledge, sensation and opinion as three grades of cognition, linking them to the three Fates, and treated mathematics as the bridge between pure thought and the senses. Unity and duality he called gods, and between gods and mortals he placed daemonic powers; happiness, he held, meant a good daemon dwelling within.
Aristotle attacked his view that Plato's ideal numbers are the same as ordinary mathematical ones, arguing that this would make them subject to arithmetic. Among those said to have heard his lectures were Zeno the Stoic, Epicurus and Polemon, whom he had rescued from a dissolute life and who succeeded him. He died in 314/3 BC after tripping over a bronze pot at home.
Source: Xenocrates
