Zachariah Wrublewski

There has been a sharp increase in the use of impossible worlds as theoretical tools for solving difficult philosophical problems. Some philosophers, however, warn against their use. For example, Timothy Williamson argues that impossible worlds should not be used in an analysis of conditionals because they do not provide a compositional semantics. In this paper, we set out to resolve some of the potential problems associated with impossible worlds, thereby providing justification for their uses in a variety of contexts and applications. Graham Priest provides two directives for an account of impossible worlds. We argue that Priest’s directives, and, thus, the traditional view on impossibility, overextend the class of impossible worlds. We argue that all worlds, possible or impossible, are describable and that nonsense cannot play a role in a proper description. So, putative worlds that include nonsense are not worlds at all, possible or impossible. The exclusion of nonsense sentences from worlds undermines Priest’s two directives, but by separating nonsense from impossibility, we can resolve many of the worries about the use of impossible worlds.

Epistemological accounts that make use of a safety condition on knowledge, historically, face serious problems regarding beliefs that are necessarily true. This is because necessary truths are true in all possible worlds, and so such beliefs can be safe even when the bases for the beliefs are epistemically problematic. The existence of such problematically safe beliefs would undermine a major motivation for the condition itself: the ability to evaluate how well a belief tracks the truth. This paper argues that incorporating impossible worlds into the evaluation of beliefs solves this problem, but only if the relevant account of impossible worlds entails that many impossible worlds are incredibly similar to the actual world. Further, the paper argues that, as a result of including impossible worlds, some philosophical beliefs are unsafe, and many more are potentially unsafe. But, it argues, even if this is the case, we can still make philosophical progress.

There has been a sharp increase in the use of impossible worlds as theoretical tools for solving difficult philosophical problems. Some philosophers, however, warn against their use. For example, Timothy Williamson argues that impossible worlds should not be used in an analysis of conditionals because they do not provide a compositional semantics. In this paper, we set out to resolve some of the potential problems associated with impossible worlds, thereby providing justification for their uses in a variety of contexts and applications. Graham Priest provides two directives for an account of impossible worlds. We argue that Priest’s directives, and, thus, the traditional view on impossibility, overextend the class of impossible worlds. We argue that all worlds, possible or impossible, are describable and that nonsense cannot play a role in a proper description. So, putative worlds that include nonsense are not worlds at all, possible or impossible. The exclusion of nonsense sentences from worlds undermines Priest’s two directives, but by separating nonsense from impossibility, we can resolve many of the worries about the use of impossible worlds.