Full Idea
There can be determinate countability even where there is not determinate identity; it is not in dispute that there are two electrons in the shell of a neutral helium atom, even though the identity of electrons is not determinate.
Gist of Idea
Some things (such as electrons) can be countable, while lacking proper identity
Source
E.J. Lowe (The Possibility of Metaphysics [1998], 3.3)
Book Reference
Lowe,E.J.: 'The Possibility of Metaphysics' [OUP 2001], p.62
A Reaction
If the electrons could merge like water drops, we would be unable to say when they became one object. You can roughly count waves on the sea, but when you seek an exact total, the identity problem intrudes and prevents precise counting.
Related Idea
Idea 8268 Some things (such as electrons) can be countable, while lacking proper identity [Lowe]