Difference between revisions of "Syllogism"
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A '''syllogism''' is a [[logic]]al [[argument]] that necessarily follows if two [[premise]]s are true. | A '''syllogism''' is a [[logic]]al [[argument]] that necessarily follows if two [[premise]]s are true. | ||
| − | "All cats are mammals." | + | :"All cats are mammals." |
| − | "Fluffy is a cat." | + | :"Fluffy is a cat." |
| − | Therefore | + | :Therefore |
| − | Fluffy is a mammal. | + | :Fluffy is a mammal. |
As [[linguistic]] tools, syllogisms are built from category words such as "all" "none" "some". | As [[linguistic]] tools, syllogisms are built from category words such as "all" "none" "some". | ||
| − | "No conservative voted for Obama" | + | :"No conservative voted for Obama" |
| − | "Andy is a conservative" | + | :"Andy is a conservative" |
| − | therefore, "Andy did not vote for Obama". | + | :therefore, |
| + | :"Andy did not vote for Obama". | ||
One has to be careful, however, what categories are applied and assumed. | One has to be careful, however, what categories are applied and assumed. | ||
| − | "No conservative voted for Obama" | + | :"No conservative voted for Obama" |
| − | "John did not vote for Obama" | + | :"John did not vote for Obama" |
| − | Therefore | + | :Therefore |
| − | "John is a conservative." is an example of an incorrect syllogism, as the exclusive category "no Conservative" does not rule out other people not voting for Obama. | + | :"John is a conservative." is an example of an incorrect syllogism, as the exclusive category "no Conservative" does not rule out other people not voting for Obama. |
[[Category: Logic]] | [[Category: Logic]] | ||
Revision as of 18:41, November 12, 2008
A syllogism is a logical argument that necessarily follows if two premises are true.
- "All cats are mammals."
- "Fluffy is a cat."
- Therefore
- Fluffy is a mammal.
As linguistic tools, syllogisms are built from category words such as "all" "none" "some".
- "No conservative voted for Obama"
- "Andy is a conservative"
- therefore,
- "Andy did not vote for Obama".
One has to be careful, however, what categories are applied and assumed.
- "No conservative voted for Obama"
- "John did not vote for Obama"
- Therefore
- "John is a conservative." is an example of an incorrect syllogism, as the exclusive category "no Conservative" does not rule out other people not voting for Obama.