The problem of universals is shown to be the problem of trying to determine what kinds of things concepts are, the connection concepts have with the world at large, and what effect this has on claims to knowledge of the world as it is. The problem is traced from its origin in Plato through the works of Aristotle, Alexander of Aphrodisias, Porphyry, Boethius, and Avicenna. The realist position that claims universals as real is contrasted with the nominalist one which says that only individuals exist and are real. Since knowledge of the world is acquired through concepts (universals) the nominalist is in the uncomfortable position of having to admit to not knowing the world as it really is. Scotus\u27 attempt at trying to resolve the problem ...