Plato, a legendary Athenian philosopher, lived from 429 to 347 B.C. Since Socrates didn't write anything himself, his influence and philosophy is mainly known through his pupil, Plato, who eventually surpassed his teacher through influential ideas of his own.

Since Plato inherited a sizable fortune and reputation from his aristocratic family, he had plenty of time to speculate about philosophy. At first he considered becoming a politician himself, but the death of Socrates, which Plato and others believed was unjust, disillusioned Plato with politics. Yet he remained an ivory-tower critic, best known for his firm belief in the rule of philosopher kings. Plato believed that only philosophical intellectuals could have the objectivity to govern fairly. His science of episteme sought to teach young men virtue and goodness in order to preserve the beleaguered polis of Athens. In this vein, Plato set up the Academy, one of the first schools of philosophy. Through this institution, many Greek ideas were preserved and enhanced. The Academy survived until the Roman government under Justinian disbanded it in 529 A.D.

Plato's writing has left an undisputed mark on Western thought. His most famous work, The Republic, outlines his core beliefs. In it, Plato details man's relationship with the government as well as how he should relate to other men. To Plato, a just state can only be created when men live virtuous lives. The Republic is a manual of sorts, which shows society how to achieve this virtue.