Full Idea
Exemplar theories have a selection problem. Given that individuals have an infinite number of properties, they need to explain why exemplars represent such and such properties, instead of others.
Gist of Idea
Exemplar theories need to explain how the relevant properties are selected from a multitude of them
Source
Edouard Machery (Doing Without Concepts [2009], 4.3.1)
Book Reference
Machery,Edouard: 'Doing Without Concepts' [OUP 2009], p.94
A Reaction
I have the impression that this idea rests on the 'abundant' view of properties - that every true predicate embodies a property. A sparse view of properties might give a particular quite a restricted set of properties.