more from Alfred Tarski

Single Idea 8940

[catalogued under 5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox]

Full Idea

In Tarski's account of truth, self-reference (as found in the Liar Paradox) is prevented because the truth predicate for any given object language is never a part of that object language, and so a sentence can never predicate truth of itself.


'This sentence is false' is a Liar sentence

Gist of Idea

Tarski avoids the Liar Paradox, because truth cannot be asserted within the object language


report of Alfred Tarski (The Concept of Truth for Formalized Languages [1933]) by Jennifer Fisher - On the Philosophy of Logic 03.I

Book Reference

Fisher,Jennifer: 'On the Philosophy of Logic' [Thomson Wadsworth 2008], p.38

A Reaction

Thus we solve the Liar Paradox by ruling that 'you are not allowed to say that'. Hm. The slightly odd result is that in any conversation about whether p is true, we end up using (logically speaking) two different languages simultaneously. Hm.