Aristotle

The ancient world's overachiever who wrote about EVERYTHING - physics, biology, politics, poetry, logic, ethics, you name it. Aristotle studied under Plato for 20 years, then basically said 'thanks but you're wrong about almost everything' and created his own school. He tutored Alexander the Great (awkward when Alexander conquered the world and ignored most of his teachings). His ethics are all about balance - the 'golden mean' - courage is between cowardice and recklessness, generosity between stinginess and wastefulness. Basically, don't be extreme about anything. He also thought women had fewer teeth than men and never bothered to check. Genius has its blind spots. His works dominated Western thought for 2,000 years until the Scientific Revolution was like 'umm, actually...'