Full Idea
The claim that no concept counts as sortal if an instance of it can survive its loss, runs foul of so-called phase sortals like 'embryo' and 'chrysalis'.
Gist of Idea
Sortal concepts cannot require that things don't survive their loss, because of phase sortals
Source
Crispin Wright (Frege's Concept of Numbers as Objects [1983], 1.i)
Book Reference
Wright,Crispin: 'Frege's Conception of Numbers' [Scots Philosophical Monographs 1983], p.4
A Reaction
The point being that those items only fall under that sortal for one phase of their career, and of their identity. I've always thought such claims absurd, and this gives a good reason for my view.
Related Idea
Idea 13865 'Sortal' concepts show kinds, use indefinite articles, and require grasping identities [Wright,C]