Xenocrates of Chalcedon

Born in either 396 BC or 395 BC. Died in either 339 BC or 338 BC (age ~57).

Xenocrates was a Greek philosopher and mathematician. He succeeded Speusippus as Scholarch of The Old Academy following the latter’s stroke. As is apparent, he was strongly influenced by the Pythagoreans.

Like Speusippus, Xenocrates was heavily influenced by Plato, but disagreed with his ideas in several major ways. He accepted the Doctrine of Forms, but unlike Plato believed that the Forms were mathematical numbers. He proposed his own version of The Line, in three parts: knowledge, sensation, and opinion. Knowledge is the object of pure thought and reason, apart from the phenomenal world. Sensation is that which occurrs in the phenomenal world. Opinion is a fusion of sensory perception and mathematical reason.

Xenocrates asserted the existence of three realms: the sub-lunar, the heavenly, and the super-celestial. At each realm, the divine World-Soul exerts influence. This influence appears in the form of “demons” which can be either good or bad. At the sub-lunar level, these demons manifest in the elements, which are then associated with the gods.

Xenocrates believed in the transmigration of the immortal soul, including reincarnation. As such, he advocated for vegetarianism.

Xenocrates’ contribution to philosophy is his variation on Plato’s theories. Together with Plato and Speusippus, they formed the three major interpretations of the ideas of The Old Academy which Aritotle would later attempt to refute. He is a noteworthy historical figure as the third head of The Old Academy.

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