Beginning Logic Venn diagram chapter 5

Existential Import

A proposition has existential import if it presupposes the existence of certain kinds of objects.

Traditional Interpretation

An approach that requires determining whether the class terms for universals really exist.

Modern Interpretation

An approach that suspends judgment about the existence of universal class terms.

Conversion

A manipulation of a categorical proposition where S and P are switched.

Obversion

A valid inference for all claim types (A, E, I, O) involving changing quality and adding a complement to the predicate.

Contraposition

A valid inference for A and O propositions that involves switching S and P and adding complements for both.

Venn Diagram

A diagram that represents sets and their relationships, developed by John Venn.

Categorical Proposition

A statement that asserts a relationship between two classes or categories.

A Proposition

Universal affirmative proposition asserting that all members of a subject class are contained in the predicate class.

E Proposition

Universal negative proposition asserting that no members of the subject class are contained in the predicate class.

I Proposition

Particular affirmative proposition asserting that some members of the subject class are contained in the predicate class.

O Proposition

Particular negative proposition asserting that some members of the subject class are not contained in the predicate class.