Title: Debunking Arguments and Evidence of Epistemic Failure
Abstract: You have some moral beliefs. What, if anything, could you learn about the causes and counterfactual behaviour of these beliefs such that you rationally ought to reduce confidence in them, or jettison them altogether? Some philosophers have argued that empirical evidence from evolutionary psychology shows our moral beliefs to be epistemically problematic, hence we ought to reduce confidence in those beliefs. That is, they take the evidence to supply grounds for a debunking argument against our moral beliefs. Such beliefs could be shown to be unacceptably chancy – such that a small change in the conditions of belief formation would have led to different moral beliefs (or no moral beliefs at all). Or these beliefs might be shown to be unacceptably inevitable – such that changing the moral facts would not have prompted any change in our moral beliefs. What kind of empirical evidence is required for supporting allegations of each type of epistemic failure? And when, if ever, should we reduce confidence upon learning of the evidence? In this paper, I explore the conditions under which a debunking argument is successful, and the factors that affect its impact on justification. I also make a tentative case that one prominent strand of global evolutionary debunking arguments – by Joyce (2006) and Handfield (2016) – is at best weakly supported by the current evidence from evolutionary psychology.