Abstract

Descartes introduces the theory of the material falsity of an idea in the Third Meditation. What is the purpose of this theory? Descartes also claims that his ideas of the secondary quality sensations are obscure and confused ideas. What justifies this claim and what is its significance? ;The dissertation focuses on the problem of explaining the constraints on any possible interpretation of the theory of material falsity as well as defending the view that what makes the secondary quality sensations materially false is their lack of what Descartes calls objective reality. In order to orient the reader to the concerns of Descartes as well as the historical and philosophical assumptions made both by Descartes and his opponents, the dissertation has an extensive number of appendices that supply this essential contextual information. In the Appendices, I discuss Descartes's goals in philosophy as well as the historical context in which he worked out his solutions. The appendices also consider in detail the Cartesian theory of substance, Descartes's theory of ideas, and the theory of objective reality. The theory of ideas is the keystone to understanding Descartes's philosophy. ;In the Third Meditation Descartes maintains that the sensations of heat and of cold "are so little clear and distinct that cannot say regarding them whether cold is only a privation of heat, or whether it is a real quality, or neither." I argue that as a consequence, the secondary quality sensations, like those of warmth, can have no objective reality. A secondary quality sensation lacks objective reality because otherwise the person who had it would be able to tell, contrary to Descartes's assertion, what that sensation represents. That these sensations lack objective reality explains why Descartes believes that such ideas are materially false. This interpretation can also be used to explain why Descartes is justified in believing that such ideas are obscure and confused. ;My interpretation of the theory of material falsity has major ramifications for many areas of Descartes's philosophy but especially for how to understand: How Descartes can justifiably reject Aristotelian physics. The theory of clear and distinct versus that of obscure and confused ideas. The theory of error. The foundations of Cartesian physics and knowledge of the physical world