Abstract

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