syllogism

[ sil-uh-jiz-uhm ]

noun

1. Logic. an argument the conclusion of which is supported by two premises, of which one major premise contains the term major term that is the predicate of the conclusion, and the other minor premise contains the term minor term that is the subject of the conclusion; common to both premises is a term middle term that is excluded from the conclusion. A typical form is “All A is C; all B is A; therefore all B is C.”
2. deductive reasoning.
3. an extremely subtle, sophisticated, or deceptive argument.

syllogism

/ ˈsɪləˌdʒɪzəm /

noun

1. a deductive inference consisting of two premises and a conclusion, all of which are categorial propositions. The subject of the conclusion is the minor term and its predicate the major term; the middle term occurs in both premises but not the conclusion. There are 256 such arguments but only 24 are valid. Some men are mortal; some men are angelic; so some mortals are angelic is invalid, while some temples are in ruins; all ruins are fascinating; so some temples are fascinating is valid. Here fascinating, in ruins, and temples are respectively major, middle, and minor terms
2. a deductive inference of certain other forms with two premises, such as the hypothetical syllogism, if P then Q; if Q then R; so if P then R
3. a piece of deductive reasoning from the general to the particular
4. a subtle or deceptive piece of reasoning

Word History and Origins

Origin of syllogism¹

1350–1400; < Latin syllogismus < Greek syllogismós, equivalent to syllog- ( syllogize ) + -ismos -ism; replacing Middle English silogime < Old French < Latin, as above

Word History and Origins

Origin of syllogism¹

C14: via Latin from Greek sullogismos, from sullogizesthai to reckon together, from sul- syn- + logizesthai to calculate, from logos a discourse

Example Sentences

In his book "Prior Analytics," Aristotle works out the logic of “the categorical syllogism.”

From Salon

Mr. Garland seemed stumped but replied: “At a high level of generality, it seems like a syllogism. If it’s unauthorized, it shouldn’t have appropriations.”

From Washington Times

“My answer to the question is, Abraham Lincoln wrote a syllogism about slavery,” Crow said, holding up a small, handwritten sheet of paper that’s in a protective sleeve, a word or two crossed out.

From Seattle Times

The syllogism he implies is comforting: Only idiots are afraid of sharks; you are not an idiot; therefore you are not afraid of sharks.

From New York Times

“Logic and syllogisms don’t carry us very far in the law,” he said.

From New York Times