At what point does one apple and another one apple become two apples? Is a matter of distance? Likeness? Practicality doesn’t say there must be two apples, just one apple and another one apple. Two (apples) is just an abstraction in my mind.
Perhaps I am misinterpreting, but it seems to me like this would occur whenever you formed a coherent question. "How many apples are there?" would be insoluble, whilst "how many apples are there in this room?" or "how many red apples are there resting on that table?" would result in an answer belonging to the set of naturals.
So, given you have "one (element) and one different (element)", at that point, you have, ipso facto, 2 elements.
I can simply say there's only one's of apples. The existence of the number two is optional in this case. Its existence is completely up to my own mind (Distance? Likeness? Etc.). Prove to me in this case that the number two exists outside our own minds.