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