(1) Plato. To Socrates's original but down-to-earth stress on man as moral being, Plato gave an other-worldly twist. To justify an absolute morality, he postulated an eternal, changeless, absolute World of Forms, above and apart from our changing, material universe but related to it as model to imperfect copy. Morals, science, art, etc., must be derived from these eternal principles (known only to the philosopher), not from experience. The body is inferior to the soul, which is immortal, subject to reincarnation, akin to the Forms, and capable of achieving fulfillment only after death. One Form (or Idea) corresponds to each group of things in this world which we call by a common namee.g., dogs, beds, triangles-but also good, justice, beauty. Plato introduced to Greece the idea of an actively good (but not omnipotent) God and of creation (not ex nihilo, but out of preexisting chaos and using the Forms as blueprint); rejected the more immoral myths but not polytheism as such; and developed a version of the cosmological argument (Laws 893b ff., see Aquinas).
(2) Middle Platonism. Plato's doctrines were revived from the first century b.c. more with religious than philosophical motives. The moral absolutes, the other-worldly values, the Creator remain, but each thinker makes his own significant adaptations. Influenced by Aristotle,* all postulate a remote, transcendent God (or Mind), incomprehensible except in momentary revelations, indescribable except by negatives, and active in creation only through intermediaries, e.g., a second Mind, the World-Soul, and multifarious deities, planets, spirits (Albinus). The independent Platonic Forms now become thoughts in the divine Mind. Theories about the cause of evil-matter itself (e.g., Numenius) or an evil soul within matter (e.g., Plutarch)-resemble Gnosticism.*
(3) See Neoplatonism.
W.R. Inge, The Platonic Tradition in English Religious Thought (1926); G.M.A. Grube, Plato's Thought (1935); R.E. Witt, Albinus and the History of Middle Platonism (1937); P. Shorey, Platonism Ancient and Modern (1938); R. Kiblansky, The Platonic Tradition during the Middle Ages (1939); F. Solmsen, Plato's Theology (1942); A. Fox, Plato for Pleasure (1945); A.H. Armstrong, An Introduction to Ancient Philosophy (1947).