Evolutionary Debunking, Self-Defeat, and All the Evidence

Recently, Tomas Bogardus (2016), Andreas Mogensen (2017) and – at least on one plausible reconstruction – Sharon Street (2005) have argued that evolutionary theory debunks our moral beliefs by providing higher-order evidence of error. In response, moral realists such as Katia Vavova (2014) have objected that such evolutionary debunking arguments are self-defeating. The literature lacks any discussion of whether this self-defeat objection can be handled. My overall aim is to argue that it cannot, thus filling that lacuna – and vindicating Vavova’s worry. To achieve my aim, I proceed in two steps. First, I propose a novel, prima facie promising strategy for avoiding self-defeat: evolutionary debunkers should reject Conciliationism, as defended by David Christensen (2007, 2009, 2011) and others, and instead explore Thomas Kelly’s (2010) Total Evidence View as their background view on the epistemic significance of higher-order evidence of error. Then, I show that evolutionary debunkers face insuperable difficulties trying to successfully implement that strategy. Depending on the kind of higher-order evidence of error that evolutionary considerations putatively provide, they either struggle with evidential weight or are committed to inconsistent assumptions about evolutionary counterparts. Either way, the evolutionary debunking argument from higher-order evidence of error fails.