Realism maintains that our true perceptual beliefs have objective and independent counterparts; that an external world exists as the object of perception, and independently of consciousness. The world would still be, even if there were no minds or sense experience. Subordinate theses state that the external world is the cause of experience, and that there exists a resemblance between the compound elements of perception and those of external reality, namely, between the configurations of quality-experiences and the configurations of qualities themselves.¹ Some may prefer to specify this view as an indirect perceptual realism. In the present paper that is precisely what I will understand by "realism'. It is true that the very statement of such a position is non-empirical. This does not entail, however, that realism cannot be made a basis for an empiricist epistemology. A non-empirical postulate can underlie a consistent and plausible empiricism.²