Corin Katzke

In her 2006 paper, A Darwinian Dilemma for Realist Theories of Value, Sharon Street argues that evolutionary psychology, if roughly true, undermines evaluative realism as a metaethical theory. Evolutionary psychology suggests that our moral beliefs track evolutionary pressures, and not realist evaluative truths. Therefore, Street concludes, evaluative realism entails moral skepticism. The most compelling arguments against Street's evolutionary debunking of evaluative realism suggest that its implications are unacceptable. Vavova (2014, 2021) argues that, in order to work, evolutionary debunking entails global skepticism. Parfit (2017), on the other hand, argues that constructivism — Street's alternative to realism —entails nihilism. Both Vavova and Parfit argue that that in order to avoid these unacceptable implications — one epistemic, and the other ethical — evolutionary debunking must either contradict itself or fail to undermine realism. This paper will argue that evolutionary debunking can successfully respond to both of these challenges.

After introducing the problems of moral uncertainty and intertheoretic comparability, I will show that moral realism and moral constructivism involve opposite explanatory relationships between theories and particular judgements. Based on these explanatory relationships, I will make an analogy between moral constructivism and Humeanism about natural laws one hand, and moral realism and anti-Humeanism about natural laws on the other. This analogy will allow me to show why intertheoretic comparisons of choice-worthiness are in principle possible according to moral constructivism, but not according to moral realism.