Categorical Logic

In Logic, a type of deduction associated with Aristotle, or the type of propositions used in Aristotelian deductive logic.

A categorical statement is any statement that asserts a whole or partial relationship between the subject and predicate terms of the statement.

There are four standard categorical propositional forms. Using the variables S and P (for the subject and predicate terms respectively) they are:

The four categorical propositions can be arranged by quantity (universal/particular) and quality (affirmative/negative) to form a grid known as the Square of Opposition which demonstrate the logical relationships between any two propositions on the grid. The four relationships are:

Square of Opposition