Full Idea
Natural Class Nominalists take as primitive the notion of a 'natural' class - a class of things that all resemble one another in some one respect and resemble nothing else in that respect.
Gist of Idea
Natural Class Nominalism says there are primitive classes of things resembling in one respect
Source
Cian Dorr (There Are No Abstract Objects [2008], 4)
Book Reference
'Contemporary Debates in Metaphysics', ed/tr. Sider/Hawthorne/Zimmerman [Blackwell 2008], p.47
A Reaction
Dorr rejects this view because he doesn't believe in 'classes'. How committed to classes do you have to be before you are permitted to talk about them? All vocabulary (such as 'resemble') seems metaphysically tainted in this area.