Although owing to proper basicality, phenomenal conservatism, and deliberative indispensability our axiomatic moral judgments seem to be prima facie justified, the question of potential undercutting defeaters can pose a challenge to moral knowledge. Evolutionary debunking arguments of various stripes are one of the more recent widely discussed contenders for such a defeater. Because of the likes of Michael Ruse, Richard Joyce, and Sharon Street, such arguments have attracted much attention. Their general structure features an empirical premise according to which the process of evolution has had a significant impact on the stock of even our axiomatic moral judgments. The epistemic premise has it that if the empirical premise holds, then our moral knowledge is severely challenged if not debunked altogether, and perhaps even moral realism itself, since if our epistemic faculties can't reliably put us in touch with objective moral truths, those truths are out of a job in our ontology. Since the most outspoken evolutionary debunkers are secularists, they somewhat understandably tend to smuggle something of a naturalistic origins thesis into their conception of evolution, thus precluding a divine guidance of the evolutionary process, which renders it a formidable challenge for them to evade the force of the debunking challenge. Unsurprisingly Ruse, Joyce, and Street all end up abandoning moral realism and any moral knowledge predicated on it. Theism, however, potentially provides a defeater-defeater against the evolutionary debunking argument(s) (if not a defeater-deflector), by rejecting the naturalistic origins thesis as a gratuitous theological add-on to which evolution need not be attached, carving out room for evolution to be a divinely guided process that may well ensure a correspondence between moral truth and at least our most nonnegotiable moral convictions.
