Chapter 12: Explorations in Deductive Reasoning: Categorical Logic

Categorical Logic

The branch of logic that treats categorical arguments

Categorical Argument

A deductive argument composed of categorical sentences, in which a conclusion about one category of things is drawn on the basis of information about one or more other categories of things

Categorical Sentences

Relates one category of things to another category of things by asserting that all, some, or none of one category of things either belong to, or do not belong to, a second category of things

Subject Term

States what the sentence is about

Predicate Term

Says something about the subject

Quantifier

Tells us the quantity of things in the subject category that are said to belong to the predicate category

Copula

Joins the subject to the predicate

Universal Quantity

Makes a claim about every member of the subject term category

Particular Quantity

Makes a claim about some members of the category denoted by the subject term

Affirmative Quality

Copula affirms membership in the predicate category

Negative Quality

Copula denies membership in the predicate group

Universal Affirmative Sentences

Sentences of the form “All S are P”

Universal Negative Sentences

Sentences of the form “No S are P”

Particular Affirmative Sentences

Sentences of the form “Some S are P”

Particular Negative Sentences

Sentences of the form “Some S are not P”