Plato (428/7 - 347 B.C.) was one of the most famous philosophers of all time. A type of love (Platonic) is named for him. We know about the famous philosopher Socrates through Plato's dialogues. Plato is known as the father of idealism in philosophy. His ideas were elitist, with the philosopher king the ideal ruler. Plato is perhaps best known to college students for his parable of a cave, which appears in Plato's Republic.