Listing the minor premise before the major, the four moods are:
1. Universal affirmative + universal negative → universal negative.
2. Universal negative + universal affirmative → universal negative.
3. Particular affirmative + universal negative → particular negative.
4. Particular negative + universal affirmative → particular negative.
In every case the middle term is predicate of both premises, the major is universal, and the qualities differ. These are the key structural facts.
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The Second Figure: Conditions of Validity and Four Productive Moods
Listing the minor premise before the major, the four moods are:
1. Universal affirmative + universal negative → universal negative.
2. Universal negative + universal affirmative → universal negative.
3. Particular affirmative + universal negative → particular negative.
4. Particular negative + universal affirmative → particular negative.
In every case the middle term is predicate of both premises, the major is universal, and the qualities differ. These are the key structural facts.