In (computational) commonsense reasoning, so-called typical elements of sets are used (as described her). I understand why they are useful from the point of view of applied logic but what is their philosophical status? I tried to find an answer in a few books on metaphysics and ontology but couldn't find any discussion of them.
My understanding is this: From a set-theoretic perspective, the axiom schema of comprehension could to extended to include the existence of typical elements—for every set there exists a typical element of it whose principal (extranuclear?) property is that whatever is true of it is also true of any member of the set. From a philosophical perspective, can we say that (1) if sets exist, then typical elements of sets exist and (2) sets and typical elements are distinct (though closely related) entities?