Xenocrates c. 396 BC – c. 314 BC

Xenocrates of Chalcedon was a Greek philosopher of the early Academy and the third scholarch after Plato and Speusippus, holding the office for twenty-five years. He systematized the Platonic doctrine into a triad of intelligible, sensible, and intermediate mathematical entities, and his definition of the soul as a self-moving number shaped subsequent Platonic and Pythagorean psychology. Aristotle disputed his doctrines in detail, but Xenocrates remained a respected and morally austere figure. The Athenians valued him highly, and Antipater is said to have remarked that, of all Greek philosophers, only Xenocrates could not be bribed.