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Rule of Contradiction
Contradictory statements are statements that differ in both quality and quantity
Rule of Contraries
Two statements are contrary to one another if they are both universals but differ in quality
Rule of Subcontraries
Two statements are subcontrary if they are both particular statements that differ in quality
Rule of Subalterns
Two statements are subalternate if they have the same quality but differ in quantity
1st Rule of Opposition
Contradictories cannot at the same time be true nor at the same time be false
2nd Rule of Opposition
Contraries cannot at the same time both be true, but can at the same time both be false
3rd Rule of Oppostion
Subcontraries may at the same time both be true, but cannot at the same time both be false
Principle of Reciprocal Identity
Two terms that are identical with a third term are identical to each other
Principle of Reciprocal Non-Identity
Two terms, one of which is identical with a third term and the other of which is nonidentical with that third term, are nonidentical to each other
Dictum de Omni
What is affirmative universally of a certain term is affirmed of every term that comes under that term
Dictum de Nullo
What is denied universally of a certain term is denied of every term that comes under that term
Fallacy of Illicit Major
The major term is distributed in the conclusion but not in the major premise
Fallacy of Illicit Minor
The minor term is distributed in the conclusion but not in the minor premise
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