counterpart theory

English

Noun

counterpart theory (uncountable)

1. (metaphysics) An alternative to standard possible worlds semantics in which an individual can exist in only one world, while other possible worlds contain (different) counterparts to that individual, and in which the modality operators (necessity, possibility) are replaced by quantifiers over possible worlds.
   • 1983, David Lewis, Philosophical Papers, volume 1, page 45:

     If counterpart theory calls for the rejection of some popular modal principles, that needn't worry us. But if it forces us to reject principles of the logic of identity and quantification, that is more serious.

   • 2013, Theodore Sider, John Hawthorne, Dean W. Zimmerman, Contemporary Debates in Metaphysics:

     According to counterpart theory, Humphrey himself has the modal property, might have won the election, in virtue of his counterpart having the (non-modal) property, won the election.