Single Idea 19127

[catalogued under 3. Truth / F. Semantic Truth / 2. Semantic Truth]

Full Idea

Although the theory is materially adequate, Tarski thought that the T-sentences are deductively too weak. …Also it seems that the T-sentences are not conservative, because they prove in PA that 0=0 and ¬0=0 are different, so at least two objects exist.


T-sentences say " 'p' is true iff p "

Gist of Idea

The T-sentences are deductively weak, and also not deductively conservative


Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 3.2)

Book Reference

'Stanford Online Encyclopaedia of Philosophy', ed/tr. Stanford University [], p.6

A Reaction

They are weak because they can't prove completeness. This idea give two reasons for looking for a better theory of truth.