It pays to draw a distinction between objects and relations. Relations manifest themselves when more than one object is involved. A pair of objects is an object

It pays to draw a distinction between objects and relations. Relations manifest themselves when more than one object is involved. A pair of objects is an object; it is a physical relation between pairs, the isomorphism if you will, that we call "number 2"; it manifests itself in cases when pairs can physically "snap" together solely due to the fact that their cardinalities match. I think it is the fact that a number (a count, in this case) is not tied to a single object (e.g. a pair) but rather expresses the potential of a certain physical interaction between several objects that makes understanding this difficult.