Abstract

From the time of Descartes to about the 1960s, a certain epistemological idea dominated the philosophy of mind, namely the idea that theses about the relation between mind and body are, if true, a priori truths. Much of recent philosophy of mind is devoted to the question whether that idea is right. My research is largely an attempt to argue that some recent defenses of it are unsuccessful. ;For example, Physicalism is the metaphysical thesis that every actual psychological event, property, or process is necessitated by some actual physical event, property, or process. Many philosophers believe that Physicalism is true. Until about the 1960s, those who believed it true typically believed that statements relating mind and body were a priori truths. Let us call this thesis A Priori Physicalism. Many philosophers nowadays believe, instead, that statements relating mind and body are only a posteriori truths. Let us call this thesis A Posteriori Physicalism. A number of philosophers have argued in recent years that A Posteriori Physicalism is unacceptable; on their view, Physicalists had better be A Priori Physicalists. My thesis examines the question whether that view is correct. ;I begin with a discussion of two influential arguments for the conclusion that Physicalists must be A Priori Physicalists. Chapter 1 addresses itself to an argument for the conclusion that if physicalism is true, every referring psychological expression is coreferential a priori with some referring physical expression. This argument is commonly called the Property Dualism Argument against Physicalism. I argue that the Property Dualism Argument rests on an ambiguous premise: on one reading it begs the question against A Posteriori Physicalism, on the other reading the conclusion of the Property Dualism Argument does not follow. ;Chapter 2 addresses itself to an argument of Frank Jackson's for the conclusion that Physicalists must have an a priori story to tell about how the physical nature of the actual world makes true the psychological nature of the actual world. I distinguish two ways in which this claim might be understood, and I argue that on neither way of understanding it does Jackson have a compelling argument for A Priori Physicalism. ;Finally, in Chapter 3 I turn to a more general discussion of the relation between conceivability and possibility, and its bearing on the dispute between A Priori and A Posteriori Physicalists. I focus in particular on a recent argument of David Chalmers' from the conceivability of so-called zombies to the conclusion that A Posteriori Physicalism is false. I argue that this argument fails to provide compelling reasons for rejecting A Posteriori Physicalism. I argue, first, that it misconstrues the relation between conceivability and possibility, and second, that it fails to establish that zombies are conceivable in the relevant sense