The Existential Fallacy

[Mudhammam]

Wow, that website is everything that I pretty much learned in my Introduction to Logic class this past Wednesday. Actually, some of my homework that I was going to do today is just that. Basically, the ancient philosophers came up with these diagrams to express the relationships in which the categories of all claims fall: universal affirmatives, universal negatives, particular affirmatives, and particular negatives. In simpler terms, All S are P (A-type), No S are P (E-type), Some S are P (I-type), and Some S are not P (O-type). The idea of existential import basically means that when S is a subject that does not exist in some veritable manner, the relationships between the different categorical propositions (alternation and subalternation) break down so that the only thing left to differentiate them is contradiction, or rather: statements about non-existing entities fall either to the proposition that All S are P or No S are P, of which both can be stated as true.