Skepticism

Abstract

Suppose we take for granted the self-knowledge discussed in the previous chapter. What, then, is the logical relation between psychosemantic externalism and skepticism about the external world? Much recent philosophical attention has been devoted to this question.¹ Skepticism is the view that we do not know most of the things that, pre-philosophically, we think we know about the external world. It is sometimes supported by thought experiments that appeal to the evidential similarity between the normal case and the case where one is dreaming, one is deceived by an evil demon, or one is a brain in a vat. I do not believe that skepticism is true. But I do believe that the position is coherent, that it might be (or might have been) true. I also believe that there are legitimate limitations on what we can be justified in believing about the external world; if this is a form of skepticism, then I am a skeptic of this sort. The same sort of justificatory gap does not plague the epistemic access we have to the contents of our thoughts. As we will see below, I am not alone in these judgments; many others, including externalists, want to embrace the coherence of the stronger form of skepticism, as well as the truth of the weaker form, and yet maintain the privileged status of self-knowledge. The question to which this chapter is addressed is whether externalists are able to do what they want to do.