Stephen C. Pepper was one of the most original philosophers of the twentieth century. A leader in aesthetics and art appreciation and a forceful proponent of empiricism in ethics and value theory, he provided an empirical account of metaphysics that drew on the arts, as well as the sciences. For him metaphysics was central to philosophy, and he thought of metaphysical theories--or, as he preferred to call them, "world hypotheses"--as ways of marshaling the evidence in support of the major treatments of the subject matters of such fields as ethics, aesthetics, and general value theory. He was dubious of claims to certainty or infallibility and was convinced that the evidence did not point to any one aesthetics or theory of criticism as the correct one. Rather, he maintained that at least five relatively adequate aesthetic views were supported by a like number of world hypotheses of roughly...