Full Idea
The possibility of abstract definition does not show that we have defined a property that we can know, independently of any theory, that it is physically possible for some object to possess.
Gist of Idea
If we abstractly define a property, that doesn't mean some object could possess it
Source
Alexander Bird (Nature's Metaphysics [2007], 4.2.3.1)
Book Reference
Bird,Alexander: 'Nature's Metaphysics' [OUP 2007], p.81
A Reaction
This is a naturalist resisting the idea that there is no more to a property than set-membership. I strongly agree. We need a firm notion of properties as features of the actual world; anything else should be called something like 'categorisations'.