Judging by the success of many novels and Hollywood films, we are attracted by the idea of multiple or alternate realities. And its not just in fiction, in philosophy, possible world theorists argue for a vast number of parallel worlds some marginally different from ours all of which are held to be real. But an increasing number of critics argue this is extravagant fantasy. They contend not only is there no evidence for such alternative possible worlds but they are not even thinkable from our world for we can make no sense of a universe outside of the universe.
Should we see talk of alternative and possible worlds as fundamentally misguided? Are they the metaphysical consequence of wanting to hold on to a realist account of language and make sense of modal logic, while instead we should be adopting a radically different approach? Or can we use other worlds to give us a better account of our own world, and cast light on the deep puzzles of language and reality?