Aristotle

Greek philosopher and polymath, student of Plato, tutor of Alexander the Great, founder of the Lyceum (335 BCE), and author of one of the most encyclopedic surviving bodies of work in the history of human thought — covering logic, metaphysics, ethics, politics, biology, physics, psychology, rhetoric, poetics, and meteorology. Born 384 BCE in Stagira on the Chalcidic peninsula, he entered Plato's Academy in Athens at seventeen and remained for twenty years before moving on to tutor Alexander, then returning to Athens to found his own school. His ethical masterwork Nicomachean Ethics established eudaimonia ('flourishing,' often translated as 'happiness') as the highest human good — to be pursued through the cultivation of virtue understood as a 'mean' between extremes, lived in a polity, and culminating in the contemplative life. He died in 322 BCE on Euboea after fleeing Athens during the anti-Macedonian backlash that followed Alexander's death.