Worlds and Individuals, Possible and Otherwise

Takashi Yagisawa argues for a new version of modal realism, the view that non-actual possible worlds and individuals are as real as the actual ones. The notion of reality is primitive; existence is a relation between a thing and a domain; worlds are modal indices for truth; ordinary objects are extended in spatial, temporal, and modal dimensions.

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Modal realism says that non-actual possible worlds and individuals are as real as the actual world and individuals. Takashi Yagisawa defends modal realism of a variety different from David Lewis's theory. The notion of reality is left primitive and sharply distinguished from that of existence, which is proposed as a relation between a thing and a domain. Worlds are postulated as modal indices for truth on a par with times, which are temporal indices for truth. Ordinary individual objects are conceived as being extended in spatial, temporal, and modal dimensions, and their transworld identity is explicated by the closest-continuer theory. Impossible worlds and individuals are postulated and used to provide accounts of propositions, belief sentences, and fictional discourse.