====== Modus Darii ======
A form of [[glossary:syllogism|syllogism]] in which a new affirmative existential statement is derived from general and existential statements.
> All M are P.
> Some S are M.
> Therefore, some S are P.
For example:
> All squares are rectangles.
> Some rhombuses are squares.
> Therefore, some rhombuses are rectangles.
===== Name =====
The name “Darii” is a [[wp>Mnemonic|mnemonic]] term, in which the vowels (a-i-i) indicate that the first premise is an affirmative [[glossary:universal_quantification|universal quantification]] (type “a”), and that the second premise as well as the conclusion are both affirmative [[glossary:existential_quantification|existential quantifications]] (type “i”).
Although there is an existential statement inferred from a //universal// proposition in this form, no further proof of existence is needed, as the minor statement already implies existence at the intersection of S and M.
For more information on this naming scheme, and on syllogisms in general, see the article on [[glossary:syllogism|syllogisms]] in the [[glossary:index|glossary]].
===== Variants =====
The following forms are the variants of Modus Darii and can all be transformed back into it:
* [[logic:inferences:modus_darii:modus_dimatis|Modus Dimatis]]
* [[logic:inferences:modus_darii:modus_datisi|Modus Datisi]]
* [[logic:inferences:modus_darii:modus_disamis|Modus Disamis]]
* [[logic:inferences:modus_darii:modus_darapti|Modus Darapti]]
===== See also =====
* [[logic:inferences:modus_barbara:index|Modus Barbara]]
* [[logic:inferences:modus_celarent:index|Modus Celarent]]
* [[logic:inferences:modus_ferio:index|Modus Ferio]]
===== More information =====
* [[wp>Syllogism]] on //Wikipedia//
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