## Terms in syllogism::Syllogism

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Modus::style Small::solid Logic::premise Outline::terms Premises::which Clear::forms**Terms in syllogism**
We may, with Aristotle, distinguish **singular** terms such as *Socrates* and **general** terms such as *Greeks*. Aristotle further distinguished (a) terms that could be the subject of predication, and (b) terms that could be predicated of others by the use of the copula ("is a"). (Such a predication is known as a distributive as opposed to non-distributive as in *Greeks are numerous*. It is clear that Aristotle's syllogism works only for distributive predication for we cannot reason *All Greeks are animals, animals are numerous, therefore All Greeks are numerous*.) In Aristotle's view singular terms were of type (a) and general terms of type (b). Thus *Men* can be predicated of *Socrates* but *Socrates* cannot be predicated of anything. Therefore, for a term to be interchangeable—to be either in the subject or predicate position of a proposition in a syllogism—the terms must be general terms, or *categorical terms* as they came to be called. Consequently, the propositions of a syllogism should be categorical propositions (both terms general) and syllogisms that employ only categorical terms came to be called *categorical syllogisms*.

It is clear that nothing would prevent a singular term occurring in a syllogism—so long as it was always in the subject position—however, such a syllogism, even if valid, is not a categorical syllogism. An example is *Socrates is a man, all men are mortal, therefore Socrates is mortal.* Intuitively this is as valid as *All Greeks are men, all men are mortal therefore all Greeks are mortals*. To argue that its validity can be explained by the theory of syllogism would require that we show that *Socrates is a man* is the equivalent of a categorical proposition. It can be argued *Socrates is a man* is equivalent to *All that are identical to Socrates are men*, so our non-categorical syllogism can be justified by use of the equivalence above and then citing BARBARA.{{ safesubst:#invoke:Unsubst||$N=OR |date=__DATE__ |$B=
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**Syllogism sections**

Intro Early history Basic structure Terms in syllogism Existential import Syllogism in the history of logic Syllogistic fallacies See also Notes References External links

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