Abstract

The Reliability Challenge to moral non-naturalism has received substantial attention recently in the literature on moral epistemology. While the popularity of this particular challenge is a recent development, the challenge has a long history, as the form of this challenge can be traced back to a skeptical challenge in the philosophy of mathematics raised by Paul Benacerraf. The current Reliability Challenge is widely regarded as the most sophisticated way to develop this skeptical line of thinking, making the Reliability Challenge the strongest epistemic challenge to normative nonnaturalism. In this paper, I argue that the innovations that have occurred since Benacerraf’s statement of the challenge are misconceived and confused in a number of ways. The Reliability Challenge is not the most potent epistemic challenge to moral non-naturalism. The most potent challenge comes from the fact that there is a causal condition on knowledge – or, more precisely, a becaual condition – that non-natural moral facts cannot satisfy.