  On its face, the Open Question Argument seems to beg the question against the naturalist just as much as the charge of a naturalistic fallacy. For if the naturalist holds that a given moral predicate M is equivalent in meaning to some definition N couched entirely in non-moral predicates then she is obviously committed to holding that the relevant questions are not open and the naturalist might therefore simply deny the main premise of Moore’s argument. However, the Open Question Argument can be given a non-question-begging interpretation. The crucial move is to understand the argument as an argument to the best explanation. On this interpretation, the main premise of the argument is not that the relevant questions are conceptually open, but the much more modest premise that they at least seem conceptually open to competent users of moral terms. The argument then proceeds to claim that the best explanation of its seeming to competent users of the terms that these questions are open is that they really are open. That is, after all, a relatively simple and direct explanation of the phenomenon and the sort of explanation that we seem to accept by default when considering conceptual questions in general. This argument does not beg the question insofar as the opponent of non-naturalism can grant that the relevant questions do seem open without thereby contradicting their position—the main premise of this argument does not directly entail non-naturalism.