I think that's a very reasonable way to put it. For example, https://en.wikipedia.org/wiki/Peano_axioms#Set-theoretic_models https://en.wikipedia.org/wiki/Pea

I think that's a very reasonable way to put it. For example, https://en.wikipedia.org/wiki/Peano_axioms#Set-theoretic_models https://en.wikipedia.org/wiki/Peano_axioms#Set-theoretic_mod... does not depend on having any pre-existing set of 6 objects that you can point out by ostension. Instead, you can construct one, given the concepts of ∅, ∪, and {}!