Abstract

Some may be convinced that, whether or not Lewis’ defense is successful, realism about possible worlds is unavoidable if sense is to be made of modal locutions. To show that this view is—as I believe-mistaken would be a more ambitious project than I can undertake here. But some brief comments may serve to show how extreme a view this is. If one rejects realism about possible worlds, one has at least these options: to accept that conventional modal logic can be made intelligible only by way of possible worlds, but to try to construe possible worlds syntactically or conceptually; to deny that conventional modal logic can be made intelligible only by way of possible worlds; to retreat from conventional modal calculi to variant systems. I observe that, since the usual systems are wholly insensitive to the differences of tense and mood which are crucial to natural language modal locutions, there is some motivation for scepticism about the adequacy of conventional modal logics. So I resist the suggestion that there is no alternative to thoroughgoing realism.