No Valid Categorical Syllogism contains two Negative Premises/Historical Note

Historical Note on No Valid Categorical Syllogism contains two Negative Premises

This rule of quality was axiomatic at the time of Aristotle, when the theory of the categorical syllogism was initially developed.

Sources

• 1965: E.J. Lemmon: Beginning Logic ... (previous) ... (next): Chapter $4$: The Predicate Calculus $2$: $4$ The Syllogism