 The problem of universals may be thought of as the question of what, if anything, is the metaphysical basis of our using the same predicate for more than one distinct individual. Socrates is human and Plato is human. Does this mean that there must be some one universal reality—humanity—that is somehow repeatable, in which Socrates and Plato both share? Or is there nothing metaphysically common to them at all? Those who think there is some actual universal existing outside the mind are called realists; those who deny extra-mental universals are called nominalists. Scotus was a realist about universals, and like all realists he had to give an account of what exactly those universals are: what their status is, what sort of existence they have outside the mind. So, in the case of Socrates and Plato, the question is “What sort of item is this humanity that both Socrates and Plato exemplify?” A related question that realists have to face is the problem of individuation. Given that there is some extra-mental reality common to Socrates and Plato, we also need to know what it is in each of them that makes them distinct exemplifications of that extra-mental reality.