In The Birth of Ethics, Philip Pettit carefully argues that Erewhonians would develop concepts that closely resemble our normative concepts – including our moral concepts – and that this reveals a great deal about the nature of normativity in general and morality in particular. The purported revelations about morality include: Thesis #1: Moral concepts ascribe natural properties. Thesis #2 “Full-scale” moral realism is true. Thesis #3: There is a sufficiently good answer to the question, “Why be moral?”In this paper, I (...) do not question Pettit's ingenious argument that the Erewhonians' conceptual repertoire would expand in the way described in his narrative. I instead question whether this narrative supports these metaethical theses. I argue that if our moral concepts were expressively equivalent to Erewhonian moral concepts, that would not ground a “full-scale” moral realism, nor would it give us a sufficiently compelling answer to the question “Why be moral?” Furthermore, I argue that our moral concepts are not expressively equivalent to Erewhonian moral concepts, which puts pressure on the argument that our moral concepts ascribe natural properties. Finally, contra Pettit, I argue that moral concepts do not play the same function in our lives as the analogous concepts play in Erewhonians' lives. (shrink)