Terminological Rules for Categorical Syllogisms

Question 1

What’s Rule I?

Answer 1

There must be three and only three terms. If broken, it is said that you’ve commited the Fallacy of Four Terms. The other way to break the rule is by using an ambiguous middle term. This violation is known as the Fallacy of Equivocation.

Question 2

What’s Rule II?

Answer 2

The middle term must not occur in the conclusion.

There is no name for the breaking of this rule