Underdetermination and Perceptual Skepticism

This chapter motivates narrowing the book’s focus to a particular kind of argument for perceptual skepticism (the underdetermination argument) and to two main kinds of response to it (inferential anti-skepticism and noninferential anti-skepticism). The first half of the chapter sets aside skeptical arguments (e.g. closure-based arguments) and responses to them (e.g. contextualism, contrastivism, and closure-denial) that overestimate skepticism’s appeal by taking for granted that we don’t know that skeptical hypotheses are false. It also sets aside disjunctivist and “knowledge first” responses to skepticism, both of which underestimate skepticism’s appeal by rejecting the intuitions supporting the New Evil Demon Problem. The second half of the chapter highlights the relative strength of underdetermination arguments for perceptual skepticism, according to which our sensory evidence underdetermines the truth of our perceptual beliefs based on it. This underdetermination problem requires us to be able to infer the likely truth of our perceptual beliefs via good arguments from our sensory evidence, if our perceptual beliefs are to be justified. Given that we aren’t able to make such inferences, the underdetermination argument concludes that our perceptual beliefs aren’t justified. The inferential anti-skeptic’s response insists that we are able to make such inferences. The noninferential anti-skeptic’s response says that, despite the underdetermination problem, our perceptual beliefs can be justified even if we aren’t able to infer their likely truth via good arguments from our sensory evidence.