The method of Socrates was adopted and enlarged by the most famous of all ancient writers. Aristocles, surnamed Plato (the broad-browed), was a brilliant young Athenian aristocrat who turned from poetry to philosophy on meeting, in his twentieth year, with Socrates. After travelling abroad in search of knowledge, he returned to Athens and founded his world-renowned Academy there in 387 B.C. With vast learning and puissant method, he created an influence which is not yet extinct Plato was the culminating point of Greek philosophy. In his works all the various and conflicting tendencies of preceding eras were collected under one method. This method was doubtless the method of Socrates, but much extended and improved. Socrates relied on definitions and analogical reasoning as the principles of investigation. Plato used these arts, but he added to them the more scientific processes of analysis, generalisation, and classification. In regard to his system of thought, Plato was a realist. He believed that ideas have a real existence, and that material things are only copies of the realities existing in the ideal world. He held that beauty, goodness, and wisdom are spiritual realities, from which all things beautiful, good, and wise derive their existence. In his philosophy the universe is divided into the celestial region of ideas and the mundane region of material phenomena, answering to the modern conception of heaven and earth. As the phenomena of matter are but copies of ideas (not, as some suppose, the bodily realisation of them), there arises a question: How do ideas become matter? Plato gives two different explanations. In the "Republic" he says that God, instead of perpetually creating individual things, created a distinct type (idea) for each thing, and from this type all objects of the class are made. But in a later work, the "Timæus," Plato takes another view of the origin of the world. Types are conceived as having existed from all eternity, and God, in fashioning cosmos out of chaos, fashioned it after the model of these eternal types. Plato's conception of heaven and earth as two distinct regions is completed by his conception of the double nature of the soul; or, rather, of two souls, one rational and the other sensitive. The sensitive soul awakens the divine reminiscences of the rational soul; and the rational soul, by detecting the One in the Many, preserves man from the scepticism inevitably resulting from mere sense-knowledge.