Full Idea
Accounts of sortal essentialism do not give a satisfactory explanation of why any sortals should be essential sortals, or a satisfactory account of why some sortals should be essential while others are not.
Gist of Idea
Why are any sortals essential, and why are only some of them essential?
Source
Penelope Mackie (How Things Might Have Been [2006], 8.6)
Book Reference
Mackie,Penelope: 'How Things Might Have Been' [OUP 2006], p.144
A Reaction
A theory is not wrong, just because it cannot give a 'satisfactory explanation' of every aspect of the subject. We might, though, ask why the theory isn't doing well in this area.