Primary and Secondary Qualities in Reid’s Theory of Perception

Abstract

Reid distinguishes primary and secondary qualities according to their roles in his theory of perception. According to Reid, perceptions are rightly caused conceptions of and beliefs in their objects. Sensations serve as "natural signs" or triggers for perceptions but are in no way constitutive of perceptions. This chapter explains the place of primary and secondary qualities in Reid's scheme, focusing on their role as natural signs, Reid's summary accounts of primary and secondary qualities, and Reid's treatments of various primary and secondary species. Contrary to other interpretations, this chapter shows that Reid regards secondary qualities as objective properties of physical bodies.