Syllogism

A syllogism is a logical argument that necessarily follows if two premises are true.

"All cats are mammals."

"Roger is a cat."

Therefore

Roger 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.

External links

• Aristotle's Logic - Stanford Encyclopedia of Philosophy