 What’s needed is objective differentia, not subjective ones like (a), (b), and (c). Such differentia could be of either of two sorts. First, it could express the characteristics of perceptual objects that all and only aesthetic objects have. This, Beardsley thinks, can’t be done until a great deal of knowledge of aesthetic objects and the philosophy of art is at hand; and it isn’t. Second, an objective definition could proceed by first dividing up aesthetic objects into classes according to their sensory fields—as seen, heard, felt, and so on—and then, within each field, determining what objective characteristics distinguish aesthetic objects from other perceptual objects.