Visiting moral twin earth

Abstract

This paper aims to examine the assumptions of Moral Twin Earth, an argument formulated by Terence Horgan and Mark Timmons with the intention of refuting the realistic naturalistic proposal of moral known as Cornell’s realism. The Moral Twin Earth provides some intuitive evidence that terms naming moral kinds are not rigid designators of natural properties and, therefore, it is not possible to offer a naturalistic definition for them, which is supposed to be a Cornell’s realism claim. However, in this paper, I try to demonstrate that Cornell’s realism does not assume rigid designation relations between terms for moral kinds and natural properties to support its naturalistic thesis. Instead of the identity relation between moral and natural kinds that would be brought about by the rigid designation, Cornell’s realism maintains only the metaphysical thesis that moral kinds are constituted or realized by natural properties which leaves it open the possibility of multiple realization of moral kinds. As Cornell’s realism does not commit itself with the semantic thesis that Horgan and Timmons criticize, then the Moral Twin Earth does not seem to offer an objection to this moral realism.