Universals. The problem of the universals, raised in one way or another by the ancient Greeks, became for the medieval thinkers one of the most important for all their discussions. The Latin term universalis means "that which pertains to all" contradistinguished from the particular or individual. In Plato's terminology the eidos or "idea, form" has the function of the universal. Aristotle's term, to katholon, is virtually the same as universalis. The medieval debate took its point of departure in a passage in Porphyry's introduction to the Categories of Aristotle, which posed three questions: (1) Do the universals (e.g., courage or kindness), have an independent, substantial existence of their own. or do they exist only in the human mind? (2) if they have an independent existence, is it that of a body or that of a disembodied entity? (3) Do they exist separated from the objects of sense or only within these objects? Boethius had specifically asked whether the universals are things (res) or merely names (voces, nomina). Those who held that they are res were called Realists; those who held that they are merely nomina were called Nominalists; but each school had a variety of interpretations. Erigena and William of Champeaux, for instance, might be called Extreme Realists, while Roscellinus and (much later) William of Occam took, each in his own way and according to the temper of his respective generation, the opposing stance. Both Thomas Aquinas and Duns Scotus represent a critical form of realism that modern historians of thought often call "Moderate Realism." The question had important theological ramifications in Christian thought. Augustine, inspired by his Neoplatonic background of thought, which might be said to imply an absolute realism, placed Plato's "ideas" or "forms" in the mind of God, so investing them with an eternal independence of the human mind and providing them with an eternal home. After the passing of the Middle Ages the controversy took a different guise; nevertheless it has continued in one way or another, with representatives of what may be called Critical Realism and of what may be called New Realism. Bertrand Russell, for instance, would be classified among the latter and George Santayana among the former. Many 20th c. philosophers, however, such as Quine and Goodman, take a definitely Nominalist position, while Wittgenstein has substituted for universals the notion of "family resemblances."

Geddes MacGregor, Dictionary of Religion and Philosophy, New York: Paragon House, 1989