Form of a syllogism based on the Modus Barbara, in which a negative existential proposition is inferred from an affirmative universal and a negative existential proposition.
All P are M.
Some S are not M.
Therefore, some S are not P.
For example:
All squares are rectangles.
Some polygons are not rectangles.
Therefore, some polygons are not squares.
The Modus Baroco and the Modus Bocardo are the only two modes that require an indirect proof of validity in order to be reducible to their general form (the Modus Barbara). In fact, these two modes are practically identical, the only difference is that the premises are in reverse order.
The name “Baroco” is a mnemonic term that helps to remember the most important characteristics of this mode: The “B” at the beginning indicates that it is related to the Modus Barbara, the “a” for an affirmative universal and the two “o” for negative existential statements. The “c” in the name indicates that the transformation to the basic form can only happen with a further proof of validity.