Single Idea 19237

[catalogued under 5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=]

Full Idea

The question of whether a deductive argument is true or not is simply the question whether or not the facts stated in the premises could be true in any sort of universe no matter what be true without the fact stated in the conclusion being true likewise.

Gist of Idea

Deduction is true when the premises facts necessarily make the conclusion fact true

Source

Charles Sanders Peirce (Reasoning and the Logic of Things [1898], III)

Book Reference

Peirce,Charles Sanders: 'Reasoning and the Logic of Things', ed/tr. Ketner,K.L. [Harvard 1992], p.142


A Reaction

A remarkably modern account, fitting the normal modern view of semantic consequence, and expressing the necessity in the validity in terms of something close to possible worlds.