Possibilities and Possible Worlds

Abstract

This paper argues that reference to possible worlds cannot help us to understand the nature of de re possibilities. The only context in which reference to worlds is helpful indeed is the study of modal inferences, but in that context, worlds are only formal devices. For this reason, fundamental questions in the metaphysics of modality should not concern the nature and existence of such worlds. The paper also argues that the possible world account of possibility is ultimately based on the idea of recombinability and Hume’s dictum against necessary connections between distinct existences, neither of which can help explain or determine what is possible and what is not. Possibilities should then be understood with reference to persons’, objects’ and their systems’ abilities or capacities, and no with worlds. All this does not mean that we should reject possible worlds. But whether we should postulate them or not must be decided by our best physics and its philosophical interpretation, not by metaphysics. If the best interpretation of quantum mechanics does indeed, as some claim, make essential use of such worlds, then they must be admitted in our ontology as any other objects to which theoretical terms refer.