“Existence (existential import, non-emptiness) is required —but not presumed— of any extended/distributed term, whether or not the property predicated of it is predicated positively or negatively. Lack of existential import (emptiness) of any such term renders the proposition containing it unsound, regardless of the validity of the argument’s form.”

Existential Fallacy: “Presupposing and/or failing to require existential import of extended/distributed classes of a proposition, whether quantifying/extending over some or all of the class, renders the propositions containing it unsound, regardless of the validity of the argument’s form.”

In order to know what something is, it helps to know what it isn’t, which requires that it is.

Categorical logic is about predication when existence is required, not presumed. It is not about denying the existence of any class, but denying membership of a non-empty subject class in a non-empty predicate class.

Negative universals or existentials deny membership in a non-empty predicate class of a non-empty subject class, or they are unsound denials.

Affirmative universals or existentials affirm membership in a non-empty predicate class of a non-empty subject class, or they are unsound affirmations.

ONLY with that as a basis, or ground, or foundation, can you launch any alterfactual hypotheses about possibilities.

There is a longer paper I’m working on that I will link to when it is done.