One of the primary goals of Pettit’s The Birth of Ethics is to offer a novel defense of a form of naturalistic realism in metaethics, drawing on a kind of “counterfactual genealogy” for ethical thought and talk, in a community he dubs “Erewhon”. We argue that Pettit’s argument faces a deep dilemma. The dilemma begins by noting the reasonable controversy about which metaethical view is true of our ethical thought and talk. We then ask: is the thought and talk in (...) Pettit’s Erewhon apt for the same reasonable controversy? If so, this raises doubts about Pettit’s case for naturalistic realism about Erewhonian “ethical” thought and talk. If not, this disanalogy between Erewhonian “ethical” thought and talk and our ethical thought and talk renders it difficult to argue smoothly from Erewhonian premises to conclusions about our own ethical thought and talk. We then consider an alternative use that someone might make of Pettit’s discussion of Erewhon: as part of a conceptual ethics argument that we should use “ethical” concepts that are relevantly similarly to the ones described in Erewhon. We conclude by reflecting on the broader methodological significance of the sort of dilemma that we have posed. (shrink)