Abstract

John Locke sometimes claims in An Essay Concerning the Human Understanding that secondary qualities are qualities of bodies and not simply ideas. Few commentators, however, have taken that claim seriously. This is at least partly because Locke also claims that ideas of secondary qualities do not resemble the secondary qualities of bodies and the commentators have taken these two doctrines to be irreconcilable. In this paper I shall briefly present the traditional reasons for thinking the two doctrines incompatible, and then present Locke's neglected attempt to reconcile these two claims.Thomas Reid in his Philosophical Works tries to explain the traditional interpretation of Locke's claims about the nature of secondary qualities. In doing so he cites an “ancient hypothesis“:… the mind, like a mirror receives the images of things from without, by means of the senses; so that their use must be to convey the images into the mind.