A universal, to Aristotle, is any common noun, any name capable of universal application to the members of a class: so animal, man, book, tree, are universals. But these universals are subjective notions, not tangibly objective realities; they are nomina (names), not res (things); all that exists outside us is a world of individual and specific objects, not of generic and universal things; men exist, and trees, and animals; but man-in-general, or the universal man, does not exist, except in thought; he is a handy mental abstraction, not an external presence or re-ality.
