Full name affirmative proposition A

Universal negative proposition E

Particular affirmative proposition I

Special negative proposition O

Singular affirmative proposition: a (or some S) is P

Singular negative proposition: a (or some S) is not P

summarized into four categories

Distinguish between conclusion and major and minor premises

Adjust the positions of the three categorical propositions in the syllogism according to the order of major premise, minor premise and conclusion.

Determine the proposition types of major and minor premises and conclusion, and write their standard forms

Rule 1: There are and can only be three distinct terms in a syllogism.

Rule 2: The middle term must be extended at least once in the premise

Rule 3: Terms that are not distributed in the premises must not be distributed in the conclusion.

Rule 4: No definite conclusion can be derived from two negative premises.

Rule 5 (i) If one of the two premises is negative, then the conclusion is negative; (ii) If the conclusion is negative, then one of the premises must be negative.

Rule 6: Two particular premises do not lead to a conclusion.

Rule 7: If there is a specific term in the premise, the conclusion must be specific.

omit major premise

omit minor premise

omit conclusion

Supplementary procedures and methods