Modus Camestros

Form of a syllogism based on the Modus Celarent, in which a negative universal proposition is inferred from an affirmative and a negative existential proposition.

All P are M.
No S is M.
[and there exists at least one S]*
Therefore, some S are not P.

For example:

All squares are rectangles.
No circle is a rectangle.
[and there exists at least one circle]*
Therefore, some circles are not squares.

Modus Camestros is similar to Modus Camestres, but is the weaker of the two forms, as it infers a existential statement rather than an universal one.

The name “Camestros” is a mnemonic term that helps to remember the most important characteristics of this mode: The “C” at the beginning indicates that it is related to the Modus Celarent, the “a” and “e” mark the affirmative and negative universal statements in the premisses, the “o” a negative existential conclusion.

• Modus Camestrop

• Existential fallacy
• Existential import
• Existential quantification
• Modus Celarent
• Syllogism
• Universal Quantification