Single Idea 15408

[catalogued under 5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth]

Full Idea

The valid formulas of classical sentential logic are called 'tautologically valid', or simply 'tautologies'; with other logics 'tautologies' are formulas that are substitution instances of valid formulas of classical sentential logic.

Gist of Idea

'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics

Source

John P. Burgess (Philosophical Logic [2009], 1.5)

Book Reference

Burgess,John P.: 'Philosophical Logic' [Princeton 2009], p.6