Plato (427–347 BC) was born in Athens to an aristocratic family. A student of Socrates until the latter’s death, he also studied the works of Heraclitus, Parmenides, and the Pythagoreans. Following the death of Socrates, Plato spent a number of years traveling around the Mediterranean. He eventually returned to Athens and founded a school of philosophy called the Academy (named for the field in which it was located), where he later taught Aristotle.
Plato wrote works on ethics, politics, morality, epistemology, and metaphysics. He is best known for his theory of forms, the theory that the qualities that define a thing’s existence (redness, beauty) exist in an abstract realm of forms, separate from matter. Plato believed that what was true, and therefore real, must be unchanging. Because the material world is in a constant state of change it is not true reality but a mere illusion. Plato taught that love is the longing for the Beautiful in its purest, most abstract, form. Consequently, love is what motivates all the highest human achievements.