A New Evolutionary Debunking Argument Against Moral Realism

Evolutionary debunking arguments (EDAs) claim that evolution has influenced our moral faculties in such a way that, if moral realism is true, then we have no positive moral knowledge. I present several popular objections to the standard version of this argument before offering a new EDA that has clear advantages in responding to these objections. Whereas the Standard EDA argues that evolution has selected for many moral beliefs with certain contents, this New EDA claims that evolution has selected for one belief: belief in the claim that categorical reasons exist. If moral realism is true, then this claim is entailed by all positive moral claims, and belief in it is defeated due to evolutionary influence. This entails that if realism is true, then we have no positive moral knowledge. While there may be objections against this New EDA, it is much stronger than the Standard EDA, and one realists ought to worry about.