Locke on Primary and Secondary Qualities

Abstract: In this paper, I argue that Book II, Chapter viii of Locke’Essay is a unified, self-consistent whole, and that the appearance of inconsistency is due largely to anachronistic misreadings and misunderstandings. The key to the distinction between primary and secondary qualities is that the former are, while the latter are not, real properties, i.e., properties that exist in bodies independently of being perceived. Once the distinction is properly understood, it becomes clear that Locke’s arguments for it are simple, valid and (in one case) persuasive as well.