Which of the following constitutes the canonical valid Barbara mood?

• A. No M are P; All S are M; Therefore No S are P
• B. All M are P; All S are M; Therefore All S are P
• C. All P are M; All S are P; Therefore All S are M
• D. All S are P; All P are M; Therefore All S are M

Answer: (B)

Barbara is a valid syllogistic form where two universal affirmative premises link the middle term to both the major and minor terms, yielding a universal affirmative conclusion about the minor term and major term. In the canonical Barbara mood, the premises are All M are P and All S are M, and the conclusion follows as All S are P. The reasoning is straightforward: every S is inside M, and every M is inside P, so every S is inside P. This is why the version that states All M are P; All S are M; Therefore All S are P is the correct form. The other options mix in negation or swap terms in ways that break this direct chain, so they do not produce the Barbara conclusion.