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Modus Felapton

Form of a syllogism based on the Modus Ferio, in which a negative existential proposition is inferred from negative universal and affirmative existential premisses. This form has an additional existential requirement.

No M is P.
All M are S.
[and there exists at least one M]*

Some S are not P.

For example:

No rectangle is a circle.
Some rectangles are squares.
[and there exists at least one rectangle]*

Some squares are not circles.

* Note: When an existential conclusion is inferred from universal premisses, this requires an (implicit or explicit) existential import, i.e. it must be proven that what the term refers to actually exists. In case of the Modus Felapton it is sufficient to prove existence for the middle term (M), as this also implies existence for S, whereas, in this particular case, actual existance of P is not implied.

Modus Felapton is very similar to Modus Ferio, the only difference is that the terms in the minor statement are swapped.


The name “Felapton” is a mnemonic term that helps to remember the most important characteristics of this mode: The “F” at the beginning indicates that it is related to the Modus Ferio, while the vowels indicate the types of statements used in the form: “e” and “o” stand for a negative universal and existential, the “i” for an affirmative existential statements.

See also

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