Full Idea
How far down are we allowed to go before the categories become too special to qualify as ontological categories?
Gist of Idea
How far down before we are too specialised to have a category?
Source
Jan Westerhoff (Ontological Categories [2005], Intro)
Book Reference
Westerhoff,Jan: 'Ontological Categories' [OUP 2005], p.4
A Reaction
A very nice question, because we can't deny a category to a set with only one member, otherwise the last surviving dodo would not have been a dodo.