Worlds and Individuals, Possible and Otherwise, by Takashi Yagisawa.

Abstract

Takashi Yagisawa’s monograph (Worlds) offers a new version of modal realism (Chs 1–8) and subsequent theories of intensional entities, belief contents, and fictional discourse (Chs 9–10). The hinge connecting these two parts of Worlds is the postulation of impossibilia (Ch. 8), justified along the following (familiar) lines: (i) we properly look to quantify over non-actual objects for various theoretical purposes; but, (ii) when we find that quantification restricted to possibilia produces too coarse a grain (conflating belief contents, conflating properties, and failing to discriminate trivial from non-trivial counterfactual conditionals); then, (iii) the remedy is to persist with the method of quantification, but expand ontology to include impossibilia. Yagisawa’s applications of impossibilia are undoubtedly novel in extent and detail, and deserving of serious study. But here I must confine myself to a single observation about the relationship of the applications of impossibilia to the theory of modality that precedes it. It would take some work to pull apart the cases in which Yagisawa relies only on a generic realism about impossibilia (and this seems often to be so) from those in which he relies on distinctive aspects of his own specific theory of impossibility (and of modality in general). And that work lies in wait for the reader who would refuse the underlying theory of modality, but embrace the imaginative applications of impossibilia. Henceforth, I will be concerned only with Yagisawa’s theory of modality.