Abstract
It seems undeniable that we have both sense experience of primary qualities and sense experience of secondary qualities, and yet, based on a text in the Sixth Replies among others, many commentators have thought that Descartes denied precisely this for primary qualities. One of the main burdens of this chapter is to show that Descartes does have an account of the sense experience of primary qualities and that it is to be found in Descartes's account of the faculty of imagination. The chapter argues that a version of the proof of the external world depends on a special class of ideas of this faculty. There are two sides to Descartes's account: the philosophical theory of ideas, including the taxonomy of perceptual responses developed in the Sixth Replies of the Meditations, and the empirical theory in the Optics and the Treatise on Man, and they are both treated in depth here. Finally, the chapter argues that Descartes has an empirical and philosophical account of the phenomenological fusion of primary and secondary qualities, the former accomplished by means of images in the corporeal imagination and the mechanism of referred sensations in The Passions of the Soul.