====== Modus Ferison ======

Form of a [[glossary:syllogism|syllogism]] based on the [[logic:inferences:modus_ferio:index|Modus Ferio]], in which a negative [[glossary:existential_quantification|existential]] proposition is inferred from negative [[glossary:universal_quantification|universal]] and affirmative //existential// premisses.

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<h3>Modus Ferison</h3>
{{modus_ferison.svg?nolink|Modus Ferison}}
<figcaption>Type ''EIO'', Figure ''3''<span noprint> [[app>#EI3O|Modus Ferison]]</span> \\ Parent: [[logic:inferences:modus_ferio:index|Ferio]]</figcaption>
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> No <abbr title="middle term">M</abbr> is <abbr title="major term">P</abbr>.
> Some <abbr title="middle term">M</abbr> are <abbr title="minor term">S</abbr>.
> <span conclusio>Therefore, Some <abbr title="minor term">S</abbr> are not <abbr title="major term">P</abbr>.</span>

For example:

> No <var>rectangle</var> is a <var>circle</var>.
> Some <var>rectangles</var> are <var>squares</var>.
> <span conclusio>Therefore, Some <var>squares</var> are not <var>circles</var>.</span>

//Modus Ferison// is very similar to [[logic:inferences:modus_ferio:index|Modus Ferio]], the only difference is that the terms in the minor statement are swapped.

===== Name =====

The name "Ferison" is a [[wp>Mnemonic|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 [[logic:inferences:modus_ferio:index|Modus Ferio]], while the vowels indicate the types of statements used in the form: "e" and "o" stand for a //negative// [[glossary:universal_quantification|universal]] and [[glossary:existential_quantification|existential]], the "i" for an affirmative existential statements.

===== See also =====

  * [[glossary:existential_quantification|Existential Quantification]]
  * [[logic:inferences:modus_ferio:index|Modus Ferio]]
  * [[glossary:syllogism|Syllogism]]
  * [[glossary:universal_quantification|Universal Quantification]]

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