Abstract

Externalism about thought content is the view that the identity conditions for the contents of propositional attitudes include facts about the external world and one's causal interaction with the world. This view seems to offer a promising new strategy for dealing with the problem of skepticism about the external world. The promise, however, is empty. ;Argumentatively, this dissertation is divided into two main parts. The first part aims to clarify the skeptical challenge and to set down some plausible success conditions on responses to the challenge. Two points are important. First, I argue that the skeptic is committed to the claim that the mind is logically independent of the external world. Since the externalist aims to deny this claim, externalism presents us with the right sort of response to the skeptical challenge. Second, I argue that an adequate response to the skeptical challenge must not appeal to empirical considerations. If externalism is to meet the challenge, arguments for this position must be a priori in nature. ;In the second main part of the project, I examine the views of three prominant externalists: Hilary Putnam, Donald Davidson and Tyler Burge. I argue that the views these philosophers propose are false and that even if they were true, they would be of no help against the skeptic. Specifically, I argue that the most we can get from externalism is a conclusion of conditional form: if we live in a world in which such relational facts obtain, then , it would follow that relational facts are relevant to the determination of thought content. Yet to suppose that we live in a world in which such relational facts obtain is to presuppose that we already know certain facts about the external world---i.e., that it is not the case that the actual world is a solipistic, spatio-temporal world. If I am correct in my critical assessment, externalist theories of thought content, as developed by their leading proponents, have no anti-skeptical force