Full Idea
It is far from clear that a definition of truth can lead to a philosophically satisfactory theory of truth. Tarski's theorem on the undefinability of the truth predicate needs resources beyond those of the language for which it is being defined.
Gist of Idea
Truth definitions don't produce a good theory, because they go beyond your current language
Source
Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1)
Book Reference
'Stanford Online Encyclopaedia of Philosophy', ed/tr. Stanford University [plato.stanford.edu], p.2
A Reaction
The idea is that you need a 'metalanguage' for the definition. If I say 'p' is a true sentence in language 'L', I am not making that observation from within language L. The dream is a theory confined to the object language.
Related Idea
Idea 15648 Instead of a truth definition, add a primitive truth predicate, and axioms for how it works [Halbach]