Full Idea
If all there are corpuscles of various shapes and sizes, variously arranged, it is not easy to see how we might draw the boundary lines, at any given moment, between one substance and another.
Gist of Idea
If there are just arrangements of corpuscles, where are the boundaries between substances?
Source
Robert Pasnau (Metaphysical Themes 1274-1671 [2011], 24.2)
Book Reference
Pasnau,Robert: 'Metaphysical Themes 1274-1671' [OUP 2011], p.555
A Reaction
We still have precisely that problem, and it leads to the nihilism about ordinary objects found in Unger, Van Inwagen and Merricks. I have so far found modern defences of ordinary objects unpersuasive.
Related Ideas
Idea 13575 If there are borderline cases between natural kinds, that makes them superficial [Ellis]
Idea 17410 Moseley showed the elements progress in units, and thereby clearly identified the gaps [Scerri]