Abstract

In order to defend the Cornell variety of naturalistic moral realism from Horgan and Timmons’ Moral Twin Earth objection, several philosophers have proposed what I call Normatively Enriched Moral Meta-Semantics. According to NEMMS, the natural properties that serve as the contents of moral predicates are fixed by non- moral normative facts. In this paper, I elucidate two versions of NEMMS: one proposed by David Brink, and the other proposed by Mark van Roojen. I show what these meta-semantics have in common, and how each one promises the Cornell realist a response to the Moral Twin Earth objection. I then argue that Cornell realists ought to be wary of adopting NEMMS. A naturalist realist who adopts this meta-semantics confronts a trilemma. The proponent of NEMMS owes a meta-ethical account of the relevant content-fixing normative facts. Such facts are either reducible to recognizably natural facts or they are not. If they are not reducible, then NEMMS entails the denial of ethical naturalism. If such facts are taken to be reducible to facts about agents’ actual or hypothetical attitudes, then the account renders moral facts stance-dependent. Consequently, moral realism is false. Alternatively, one might propose that the content-fixing normative facts are reducible to attitude-independent natural facts. However, such a proposal is refuted by its own Twin Earth objection