Full Idea
It seems that perdurance theory should identify Descartes with the sum of his temporal parts, but that means Descartes essentially lived for 54 years, which seems absurd, as he could have lived longer or less long than he in fact did.
Gist of Idea
If a life is essentially the sum of its temporal parts, it couldn't be shorter or longer than it was?
Source
Katherine Hawley (How Things Persist [2001], 6.10)
Book Reference
Hawley,Katherine: 'How Things Persist' [OUP 2004], p.191
A Reaction
[She credits Van Inwagen with this] I'm not clear why a counterpart of Descartes could not have a shorter or longer sum of parts, and still be Descartes. If the sum is rigidly designated, that is a problem for endurance too.