Worlds and Individuals, Possible and Otherwise

by Takashi Yagisawa

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.

Genres: Philosophy

328 pages, Hardcover

First published January 1, 2010

Reviews

[Mark · Rating 5 out of 5]

This is a metaphysical magnum opus, but a challenging one to read. Despite the fact that there is no formal logic in the book, Worlds and Individuals is incredibly thick, challenging writing that took years for me to eventually finish. Be warned, while Yagisawa's writing is clear and efficient, it is brutally dry. (the one joke he did manage to slip in cracked me up more than it probably deserved because it was so out of place)

Worlds and Individuals is an attempt to build upon the work of David Lewis in On the Plurality of Worlds; that a spatiotemporally separated multiverse of possible worlds is real and should be accepted. He mostly adheres to Lewis’ view, fleshes it out into a grid system (with spatial, temporal, and modal coordinates), and then attempts to make it even more maximalist by including worlds that are impossible either logically, metaphysically, conceptually, or in any other k sense of possibility. Yagisawa travels from corner to corner of metaphysical literature to make his case (offering beautiful overviews of many other philosophers while doing so). 

I am pretty much a modal realist and most certainly a four-dimensionalist, so I found Yagisawa's tessellation of the modal universe interesting and compelling. I don’t, however, find his push for including impossible worlds convincing for two reasons. First, the use cases for them are niche (unlike those of possible worlds as defended by Lewis in Plurality). Secondly, his belief on what is and isn’t metaphysically impossible (which he centers his argument on) doesn’t jive with me. He leans on the work of Saul Kripke a lot to suppose that a ton of worlds that seem perfectly possible on all levels aren’t because of what feels like technicalities or semantics. (That said, I was happy to learn more about Kripke by osmosis, who somehow I have not read yet)

All said, I enjoy reading philosophy that is imaginative, ambitious, but still dense, despite whether I am convinced by it or not. And you can’t get much larger in scope than what Yagisawa has set forth here. His idea of an infinite five-dimensional modal “hyperblob” will live with me forever.