  If either of the last two replies to Mackie’s objection works then it can be redeployed against this objection. For if either of those replies works then the non-naturalist can explain why the relevant moral judgements necessarily are motivating, which trivially entails that anyone who makes the relevant moral judgements either is appropriately motivated or is practically irrational. If, for example, it is an analytic truth that a judgment does not count as moral unless it is appropriately motivating then it trivially follows that anyone who accepts a moral judgment is appropriately motivated or is practically irrational simply because it follows that anyone who accepts such a judgment is appropriately motivated. However, these strategies are problematic in part for just the reason that Mackie’s version of internalism is problematic—both seem to make a certain kind of practical irrationality impossible by asserting that making a moral judgment guarantees appropriate motivation. In particular, it seems possible, though irrational, for an agent to judge that he is required to do something and yet not be motivated at all to do it. So perhaps non-naturalists should instead either try to accommodate Smith’s practicality requirement on moral judgement without committing themselves to a form of judgement internalism as strong as the one Mackie seemed to have in mind or argue against the practicality requirement. Of course, if Smith’s practicality requirement on moral judgement is sound then accommodating it is a challenge faced by every meta-ethical theory, but consideration of how the requirement might be accommodated suggests that the problem is especially pronounced for the non-naturalist.