Scepticism, evidential holism and the logic of demonic deception

Sceptical arguments in epistemology typically employ sceptical hypotheses, which are rivals to our everyday beliefs so constructed that they fit exactly the evidence on which those beliefs are based. There are two ways of using a sceptical hypothesis to undermine an everyday belief, giving rise to two distinct sorts of sceptical argument: underdetermination-based and closure-based. However, both sorts of argument, as usually formulated in the literature, fall foul of evidential holism, for they ignore the crucial role of background beliefs. An analogy with the philosophy of science makes this point explicit. There is no simple way to “holism proof” the two sceptical arguments.