David Lewis’s Neglected Challenge: It’s Me or God

I begin by sketching a dialectic typical of modern discussions of the ontological argument and explain the underlying modal principles. I will not pursue this well-worn dialectic. Instead I will explicate David Lewis’s valid reconstruction (in first order predicate logic) of St Anselm’s argument in Proslogion-II. Lewis’s objections to this argument are based on his idiosyncratic views about modality. Implicitly, Lewis presents a challenge: either I am right about modality, or there is a sound version of the ontological argument. More specifically, Lewis claims there is no good reason to supposethere is anything special about the actual world. I suggest there is good reason to think that must be incorrect. Thus we are left with a formal version of the ontological argument for God’s existence that for all we have seen here looks eminently viable.