Modal Realism, Moral Indifference, & Modal Necessitarianism




Babaie, Quintin

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David Lewis's Genuine Modal Realism posited the necessary and concrete existence of infinitely many worlds. This generates two concerns: the problem of moral indifference and the problem of necessitarianism. I argue that these problems are genuine objections to Lewis's account. In Section 2, I address the problem of moral indifference, an objection introduced by Robert Adams. If the overall value of the totality of metaphysical reality (i.e. the pluriverse) is necessarily fixed, then we have no better moral reason to actualize goods over evils. Lewis argued that, despite the pluriverse being necessarily unalterable, our motivation to actualize goods is owed to our duty to not become evildoers. We have no causal bearing over what happens in any world other than our own, so we should focus on how we act here, even though the overall value of the pluriverse is never made better or worse (it remains equal). I argue that this solution is inadequate in that it fails to be impartial to our counterparts of whom we logically, although not causally, influence. I provide argumentation that those whom we logically influence ought to be taken into our moral calculus and so Lewis's solution is inadequate. I argue in Section 3 that there are contexts in which I have all my properties essentially, which entails necessitarianism. However, I conclude that Lewis might have been comfortable with these consequences without abandoning or modifying his view.


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Analytic Philosophy, Modality, Possible World Semantics