Full Idea
Mill held that numbers are a kind of very general property that objects possess.
Gist of Idea
Numbers are a very general property of objects
Source
report of John Stuart Mill (System of Logic [1843], Ch.4) by James Robert Brown - Philosophy of Mathematics
Book Reference
Brown,James Robert: 'Philosophy of Mathematics' [Routledge 2002], p.55
A Reaction
Intuitively this sounds hopeless, because if you place one apple next to another you introduce 'two', but which apple has changed its property? Both? It seems to be a Cambridge change. It isn't a change that would bother the apples. Kitcher pursues this.