Metaphysics is the science that seeks to define what is ultimately real as opposed to what is merely apparent. The contrast between appearance and reality, however, is by no means peculiar to metaphysics. In everyday life people distinguish between the real size of the Sun and its apparent size, or again between the real color of an object (when seen in standard conditions) and its apparent color (nonstandard conditions). A cloud appears to consist of some white, fleecy substance, although in reality it is a concentration of drops of water. In general, men ...