Which fallacy occurs when a conclusion follows two negative premises?

• A. No conclusion follows from two negative premises
• B. Exclusive Premises
• C. Undistributed Middle
• D. Illicit Major

Answer: (B)

When both premises are negative, there’s no way to connect the subject and the predicate through a middle term, which is essential for a valid syllogism. Negative premises restrict or deny members of each class but do not establish any shared class or link between the subject and the predicate; without that link, a conclusion about the relationship between those terms cannot be validly drawn. This situation is known as the fallacy of exclusive premises: you’re trying to infer something from two negative statements, and such a move is not a valid form of reasoning in traditional syllogistic.

For example, No A is B and No B is C do not entail anything about A and C, so drawing a conclusion like No A is C (or any other substantive link between A and C) would be fallacious. The other names describe different structural mistakes in syllogisms—undistributed middle concerns the middle term not being distributed, and illicit major concerns distributing the major term in the conclusion—so they don’t capture the exact issue of pairing two negative premises to derive a conclusion.