Full Idea
If you say "I am going to drive this car", and I say "That's true", that is very different from my saying "I am going to drive this car".
Gist of Idea
Asserting the truth of an indexical statement is not the same as uttering the statement
Source
Hilary Putnam (Representation and Reality [1988], §4 p.68)
Book Reference
Putnam,Hilary: 'Representation and Reality' [MIT 1992], p.68