Bryan Frances

Many theorists have contended that since the mind depends on the brain, the contents of our thoughts are determined by just the intrinsic physical properties of our bodies. In the first part of my dissertation I examine this theory's negation, anti-individualism, by investigating the "Twin-Earth" thought experiments of Putnam and Burge. Although anti-individualism has recently become widely accepted, I argue that none of the arguments given thus far are sound; nor has the theory been given a proper formulation. I also argue that no one has articulated an interesting and true version of externalism, the related idea that if one is thinking, for example, that water is wet, then one's environment has certain empirical features . However, I then proceed to present a true version of externalism and a sound argument for a version of anti-individualism. ;In the past few years many theorists have argued that the Twin-Earth arguments, if they prove anything, have stunning implications: they refute physicalism, scepticism, authoritative self-knowledge, and the causal construal of psychological explanation; and they show that the contents of our thoughts that are appealed to in ordinary psychological explanation are not the contents captured by the sentences we use in those explanations. I attempt to refute all these arguments. ;In the second part of the dissertation I argue against the thesis that thought and action tokens exist and are, at bottom, physical entities. Roughly put, one of the main premises of the main argument is that if an action token has a physical makeup then there cannot be radically incompatible but equally plausible proposals regarding what that makeup is; but since there are such proposals, the tokens have no physical makeup. I then formulate a naturalist but nonphysicalist view of mental tokens

Content externalism is the dominant view in the philosophy of mind. Content essentialism, the thesis that thought tokens have their contents essentially, is also popular. And many externalists are supporters of such essentialism. However, endorsing the conjunction of those views either (i) commits one to a counterintuitive view of the underlying physical nature of thought tokens or (ii) commits one to a slightly different but still counterintuitive view of the relation of thought tokens to physical tokens as well as a rejection of realist physicalism. In this essay I reveal the problem and articulate and adjudicate among the possible solutions. I will end up rejecting content essentialism