Full Idea
The nominal definition of truth, namely that it is agreement of cognition with its objects, is here granted and presupposed; but one demands to know what is the general and certain criterion of the truth of any cognition.
Gist of Idea
We must presuppose that truth is agreement of cognition with its objects
Source
Immanuel Kant (Critique of Pure Reason [1781], B082/A58)
Book Reference
Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.197
A Reaction
I am puzzled by the second part of this, as the demand for a criterion (or justification) seems to me to have no part at all in our notion of what truth is in itself. It is a puzzle that Kant seems to accept the concept of truth used by simple realists.