No M is P. Some M are S. ∴ Some S are not P.
No rectangle is a circle. Some rectangles are squares. ∴ Some squares are not circles.
Modus Ferison is very similar to Modus Ferio, the only difference is that the terms in the minor statement are swapped.
The name “Ferison” 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.