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Personal Identity

Perdurantism

(Text as at 26/11/2007 23:25:26)

*** THIS IS NOT THE LATEST VERSION OF THIS NOTE ***

As developed by Quine, David Lewis, Ted Sider and others. Perdurance is to e contrasted with Endurance¹. Finally, Exdurance² (of which I’m currently ignorant) – see "Sider (Ted) - Four-dimensionalism: An Ontology of Persistence and Time". "Kurtz (Roxanne) - Introduction to Persistence: What’s the Problem?", the introduction to "Haslanger (Sally) & Kurtz (Roxanne), Eds. - Persistence : Contemporary Readings" provides a good overview of these matters. The logical problems with 4-D need to be carefully considered and, for good or ill, the four-dimensional approach has the disadvantage of undermining the reduplication objection to identity³ being maintained in certain fission⁴ thought experiments⁵. Does 4-D imply fatalism⁶? A thing is a 4-D object, but not only do we not know the future, but the future may not even exist. How does this tie in with Lewis’s realism about possible worlds? Maybe if possible worlds are real, all possible futures are real as well.

Note that perdurantism is inimical to a high view of substance. A temporal worm cannot change, it just is. The purpose of positing substances is as the enduring things that change. Perdurance also impacts on Leibniz’s Law, where property exemplification is usually taken to be relative to a time. Look at the adverbial defence of endurantism. See "Haslanger (Sally) - Endurance and Temporary Intrinsics" (probably … this is the explicit response to Lewis, though there are also "Haslanger (Sally) - Persistence, Change, and Explanation", "Haslanger (Sally) - Persistence Through Time" and "Haslanger (Sally) - Humean Supervenience and Enduring Things"; and "Kurtz (Roxanne) - Introduction to Persistence: What’s the Problem?" in "Haslanger (Sally) & Kurtz (Roxanne), Eds. - Persistence : Contemporary Readings" seems to cover much the same ground). If perdurantism really is incompatible with a high view of substance, then I may not need a chapter on perdurance (though I would have thought that I would need to argue for the incompatibility), and I can thereby ignore perdurantist objections to the cogency of reduplication objections.

Note also that Olson sets perdurance to one side. He assumes that we are concrete substances that “endure through time by being wholly present at different times”. He also sets to one side two other issues, namely that there are no such things as persons (taken to be “rational conscious beings such as you and I”) and that the classical notion of strict numerical identity is correct, rejecting relative identity. See "Olson (Eric) - The Human Animal: Introduction", pp. 4-5 and "Olson (Eric) - The Human Animal: Alternatives", both in "Olson (Eric) - The Human Animal - Personal Identity Without Psychology". He claims that if any of these assumptions is false, then there are no substantive metaphysical questions of our identity over time, only semantic ones.