Debunking Morality: Lessons from the EAAN Literature

Abstract

This article explores evolutionary debunking arguments as they arise in metaethics against moral realism and in philosophy of religion against naturalism. Both literatures have independently grappled with the question of which beliefs one may use to respond to a potential defeater. In this article, I show how the literature on the argument against naturalism can help clarify and bring progress to the literature on moral realism with respect to this question. Of note, it will become clear that the objection that the moral realist begs the question, when appealing to the truth of some of her moral beliefs, is unsuccessful.

Can Moral Realists Deflect Defeat Due to Evolutionary Explanations of Morality?

“…XX Pill Case: You learn that a pill, called ‘XX’, destroys the cognitive reliability of 95% of those who ingest it. You take the pill and come to believe both that I′ve ingested XX and P(R/I′ve ingested XX) is low (Moon, , p. 3).…”

“…According to Moon, realists have an undermining defeater for R m – the belief that their moral cognition is generally reliable – if they believe that the probability is low that our moral cognition is reliable if moral realism is true and moral cognition is an adaptation. Moon assumes that realists do accept that the probability is low that R m is true, conditional on the claim that moral realism and the evolutionary claim are true (Moon, , p. 9). Adherents of the third‐factor response want to use the morality claim to conclude that the probability that R m is true is at least moderately high.…”

“…If the challenge succeeds, and if justification is required for knowledge, then objective moral knowledge seems impossible. Moon () understands the reliability challenge to be a probabilistic challenge. Accordingly, the reliability challenge provides an epistemic defeater for R m , where R m stands for the belief our moral beliefs are generally reliable, for anyone who believes that the probability is low that our moral beliefs are reliable, given our evolutionary past and the truth of moral realism (Moon, , pp.…”

“…Realists seem to have a straightforward answer to this challenge: so‐called third‐factor accounts assume the truth of some particular, substantive ‘Morality Claim’ M (Moon, , p. 7), and then use M to demonstrate that our moral beliefs are by and large reliable (e.g. Enoch, ; Wielenberg, ; Brosnan, ; Skarsaune, ).…”

“…For instance, the morality claim favoured by realist David Enoch is that ‘survival or reproductive success is at least somewhat good’ (Enoch, , p. 430). Faced with a probabilistic version of the reliability challenge, realists might argue that, given that M is true, there is a moderately high probability that R m is true, too (Moon, , p. 7). Hence, our moral beliefs seem justified after all and therefore the reliability challenge is thwarted.…”