Individuation and the Realism/Nominalism Dilemma: The Case of the Middle Ages

After reviewing various formulations of the problems of universals and individuation, this essay considers the dialectic that informs the relationship between the two. This dialectic involves a distinction between a realist theory of universals that satisfies the requirements of science but fails to account for the non-instantiability of individuals and a nominalist theory of universals that fails to satisfy the requirements of science but accounts for the non-instantiability of individuals. Inadequacies found in one view tend to motivate movement to the other view. But, like a pendulum swing, this movement inevitably involves facing what motivated the original view. This dialectic is illustrated by a consideration of the views of five medieval authors: Boethius, Peter Abelard, Thomas Aquinas, John Duns Scotus, and William of Ockham.