> What, to you, would not qualify as a human abstraction?
Nothing insofar as "what" implies a load of human abstractions. But it's clear that there is a lot of "stuff" out there that no human has ever experienced. It is extremely improbable that humans exist at a "Goldilock's scale" wherein we are even physically capable of experiencing "everything" and of finding boundaries on the universe.
> Absolutely. See Tarski's axiomatization of the real numbers, for instance.
I meant counting in the broadest sense, which is where numbers themselves emerge from. It seems plausible that there are alien modes of cognition that don't rely on the notion of object and can approach continuous "stuff" more directly. Maybe even some terrestrial organisms work this way.
What, to you, would not qualify as a human abstraction?
> How do you define quantity, and can you do it without the notion of counting and discrete objects?
Absolutely. See Tarski's axiomatization of the real numbers, for instance.