ABSTRACT
On an optimistic version of realist moral epistemology, a significant range of ordinary moral beliefs, construed in realist terms, constitute knowledge – or at least some weaker positive epistemic status, such as epistemic justification. The debunking challenge to this view grants prima facie justification but claims that it is debunked (i.e. defeated), yielding the final verdict that moral beliefs are ultima facie unjustified. Notable candidate debunkers (i.e. defeaters) include the so-called evolutionary debunking arguments, the Benacerraf-Field challenge, and persistent moral disagreement among epistemic peers. Such defeaters are best treated as higher-order evidence – viz, evidence contesting the merits of the first-order evidence on which moral beliefs are based. This chapter first develops a theory of higher-order defeat in general, which it then applies to debunking in particular. The result is that the challenge fails entirely on epistemic grounds – regardless of whether its empirical and metaphysical presuppositions are correct. An advantage of this purely epistemic defence over alternative strategies is that the former extends even to laypeople who themselves lack the expertise necessary to formulate an adequate response. However, this leaves open the prospects for non-epistemological interpretations of debunking (e.g. moral or ontological). The chapter therefore concludes with brief suggestions in that direction.
