Full Idea
Tarski defined the class of true sentences by giving the extension of the truth predicate, but he did not give the meaning.
Gist of Idea
Tarski define truths by giving the extension of the predicate, rather than the meaning
Source
comment on Alfred Tarski (The Concept of Truth for Formalized Languages [1933]) by Donald Davidson - Truth and Predication 1
Book Reference
Davidson,Donald: 'Truth and Predication' [Belknap Harvard 2005], p.27
A Reaction
This is analogous to giving an account of the predicate 'red' as the set of red objects. Since I regard that as a hopeless definition of 'red', I am inclined to think the same of Tarski's account of truth. It works in the logic, but so what?