When Are Objects Parts?

Abstract

That there are deep and intractable metaphysical problems about material objects is evident from the unresolved antinomies and paradoxes involving material objects. The best known of these are about artifacts, the puzzle of the Ship of Theseus being the best known of all. Others, at least as worthy of remark, involve living organisms. If a cat's tail is cut off, for example, it seems natural to describe this episode in words that appear to imply that the cat becomes identical with a former proper part of itself-a violation of the attractive modal principle that a thing and another thing cannot become a thing and itself. Or, talking of cats, consider a cat that is composed at t of certain atoms arranged in a certain way; it is at least logically possible for those very same atoms to be arranged in exactly the same way at some later time, and then to compose a different cat; but that apparently implies that certain small material objects can compose one large material object at t, and, even though arranged in precisely the same way, compose a distinct material object later. How could that be? All, or almost all, of the antinomies and paradoxes that the philosophical study of material objects is heir to involve the notion of parthood. I believe, though I shall not argue for this thesis, that most of the great, intractable metaphysical puzzles about material objects could be seen to have quite obvious solutions by one who