Aristotle. (Corbis Corporation. Reproduced with permission.)

384-322 B.C.

Greek Philosopher

By any measure, Aristotle ranks as one of the greatest geniuses who ever lived. He completely reworked Plato's philosophy and established it on a firm systematic basis. He formulated the disciplines of logic, psychology, and embryology, and made important contributions to the study of zoology, medicine, anatomy, physiology, and other life sciences.

Aristotle was born in the coastal town of Stagira in northern Greece. His father Nicomachus was court physician to King Amyntas III of Macedonia. His mother Phaestis was from a prominent family in Chalcis on the Greek island of Euboea. Both parents died when Aristotle was young. He was then raised by his scholarly uncle Proxenus, who gave the boy a wide-ranging education.

At the age of 17, Aristotle enrolled in the Academy of Plato in Athens. He was Plato's student and associate for 20 years, until...