Rule 1. When the major premiss is affirmative, the minor must be
universal.
Rule 2. When the minor premiss is particular, the major must be
negative.
Rule 3, When the minor premiss is affirmative, the conclusion must
be particular.
Rule 4. When the conclusion is negative, the major premiss must be
universal.
Rule 5. The conclusion cannot be a universal affirmative.
Rule 6. Neither of the premisses can be a particular negative.
§ 607. The special rules of the first figure are merely a reassertion in another form of the Dictum de Omni et Nullo. For if the major premiss were particular, we should not have anything affirmed or denied of a whole class; and if the minor premiss were negative, we should not have anything declared to be contained in that class. Nevertheless these rules, like the rest, admit of being proved from the position of the terms in the figure, combined with the rules for the distribution of terms (§ 293).
Proof of the Special Rules of the Four Figures.
FIGURE 1.
§ 608. Proof of Rule 1.—The minor premiss must be affirmative.