Reply to Wilson Mendonça’s “Supervenience arguments against robust moral realism”

Abstract

In his “Supervenience arguments against robust moral realism”, Wilson Mendonca sets out to defend robust moral realism (the thesis that moral properties are not identical to natural properties) against the Explanatory Argument based on Supervenience. According to this argument, robust realism is unable to account for specific supervenience facts; given that the identification of moral and natural properties allows one to account for such facts, robust realism has an explanatory disadvantage vis-a-vis reductive realism. Mendonca’s answer consists in holding (i) that reductive realism has trouble accounting for the asymmetric character of specific supervenience facts and (ii) that the notion of reduction by analysis, which allows one to properly explain specific supervenience facts, supports only a weak form of reductionism that is compatible with robust realism. I argue that these claims are false and that, therefore, Mendonca fails to show that the Explanatory Argument is not a threat to robust realism. Keywords: robust moral realism, supervenience, moral reductivism, reduction by identity, reduction by analysis.