Abstract

Terence Horgan and Mark Timmons have written a number of articles where they use their Moral Twin Earth thought experiment to attack the new moral realism. The new moral realism is based on advances made in the philosophy of language that allows us to introduce synthetic definitions of moral terms. The Moral Twin Earth thought experiment relies in crucial ways on the use of intuitions. Specifically, it relies on the intuitions that were Earthers and Twin Earthers to meet, they would be able to have genuine moral disagreements. Horgan and Timmons rely on that intuition when they argue that the meaning of the relevant terms on Earth and Twin Earth must be the same. I will argue that we can accept that Earthers and Twin Earthers can have genuine moral disagreement while at the same time claim that the terms they use have different referents and so different semantic meaning. That is, having genuine disagreements does not require that the semantic meaning or the reference of the terms used in the debate being the same.