Which rule states that if either premise is negative, the conclusion must be negative?

• A. No conclusion can follow from two negative premises
• B. If the two premises are affirmative, the conclusion must be affirmative
• C. If either premise is negative, the conclusion must be negative
• D. The middle term must be distributed at least once

Answer: (C)

In traditional syllogistic, negation in the premises constrains what can be valid in the conclusion. If a premise declares that a relationship is denied (for example, No S is P), and the other premise places another term M inside S (for instance, All M is S), then M cannot have the relation to P either because S has no members in common with P. The conclusion must reflect that by being negative: No M is P. If the conclusion were affirmative, it would assert something not guaranteed by the given premises. So, when either premise is negative, the conclusion must be negative. The other rules describe different patterns—what happens when both premises are affirmative, or how the middle term must be distributed—but this one specifically ties negation in the premises to a negative conclusion.