### Single Idea 18755

#### [catalogued under 5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence]

Full Idea

A model of a language assigns values to non-logical terms. If a sentence is true in every model, its truth doesn't depend on those non-logical terms. Hence the validity of an argument comes from its logical form. Thus models explain logical validity.

Gist of Idea

Validity is explained as truth in all models, because that relies on the logical terms

Source

Vann McGee (Logical Consequence [2014], 4)

Book Reference

'Bloomsbury Companion to Philosophical Logic', ed/tr. Horsten,L/Pettigrew,R [Bloomsbury 2014], p.36

A Reaction

[compressed] Thus you get a rigorous account of logical validity by only allowing the rigorous input of model theory. This is the modern strategy of analytic philosophy. But is 'it's red so it's coloured' logically valid?

Related Idea

Idea 18759
Identity is invariant under arbitrary permutations, so it seems to be a logical term **[Tarski, by McGee]**