Otherwise known as
syllogistic logic, and constrasted with
propositional logic and
predicate logic, the form of logic discovered by
Aristotle.
The categorical is primarily the evaluation of
arguments consisting of
syllogisms of three catagorical statements, that is, sentences which begin with one of the quantifers "ALL", "SOME" or "NOT" and which seperate a
subject term and a
predicate term with a
copula ("ARE" or "ARE NOT"). Through the use of
Venn Diagrams or an ancient conceptual tool known as the
square of opposition, the
validity of any such syllogism can be derived from their form alone.