Identify the figure and mood of the following: "All sodium salts are…

CONCEPT

In a categorical syllogism, the mood records the forms of the major premise, minor premise, and conclusion in that order. A is a universal affirmative proposition: All S are P.

A syllogism’s figure is determined by the position of the middle term in the two premises. The Barbara layout is M–P; S–M; therefore S–P.

APPLICATION

Let S = soaps, M = sodium salts, and P = water-soluble substances.

1. The major premise is All M are P. It is an A proposition.

2. The minor premise is All S are M. It is an A proposition.

3. The conclusion is All S are P. It is an A proposition.

4. Thus the mood is AAA. The middle term M is the subject of the major premise and the predicate of the minor premise, giving the M–P / S–M layout.

CROSS-CHECK / CONTRAST

The standard form M–P; S–M; therefore S–P is Barbara, written AAA–1.

• AEI with M as predicate in both premises has proposition forms A, E, and I.

• AAA with M as subject in both premises has three A propositions but a different middle-term layout.

• AEI with M as predicate in the major premise and subject in the minor premise has proposition forms A, E, and I.

• AAA with M as subject in the major premise and predicate in the minor premise has three A propositions and the M–P / S–M layout.

Therefore, the classification is AAA–1 (Barbara).