In Defence of Magical Ersatzism

David Lewis' objection to a generic theory of modality which he calls ‘magical ersatzism’ is that its linchpin, a relation he calls ‘selection’, must be either an internal or an external relation, and that this is unintelligible either way. But the problem he points out with classifying selection as internal is really just an instance of the general problem of how we manage to grasp underdetermined predicates, is not peculiar to magical ersatzism, and is amenable to some familiar solutions. He provides no compelling grounds for thinking that classifying selection as external is unintelligible, and his argument has a false presupposition. I conclude that magical ersatzism is still a viable option in the metaphysics of modalit