Branching versus Divergent Possible Worlds

David Lewis ’ modal counterpart theory falls prey to the famous Saul Kripke’s objection, and this is mostly due to his ‘static ’ ontol-ogy (divergence) of possible worlds. This paper examines a genuinely realist but dif-ferent, branching ontology of possible worlds and a new definition of the counterpart re-lation, which attempts to provide us with a better account of de re modality, and to meet satisfactorily Kripke’s claim, while being also ontologically more ‘parsimonious’. §1) David Lewis ’ modal counterpart theory is based on the relation of similarity: in short, some-thing is an other-worldly counterpart of me if it is an individual inhabiting a different possible world who resembles me as for the important features of mine and who resembles me more closely than any other object in that world; it is important that those individuals, my counterparts, are not (numerically) identical to me: they all exist in their own worlds and I am the only one inhabit-ing the actual world. There are neither causal nor spatiotemporal relations between them and me— what there is, is a relation of similarity and that’s how we can say that they are what I would be, would the world be different. Counterpart theory leads to a famous difficulty raised by Saul Kripke [2, p. 45] precisely because it is a world-bound individuals theory, which permits to individuals to inhabit just one single world and no more. It is this feature of Lewis’ theory that yields objections showing that it ∗For very helpful comments on earlier versions of this paper, I would like to thank Gianfranco Soldati, Kevin Mulligan, Martine Nida-Rümelin, Fabrice Correia, Philip