would express an identical proposition, and we can and do, on occasion, decide the truth of a single proposition.(5) So the proper conclusion of the argument must be the stronger claim that truth is redundant and not merely primitive.
Truth, however, is redundant: a sentence and its truth ascription express identical propositions or thoughts.
If the challenge cannot be met, then we are invited to conclude that truth has no content -- that a sentence and its truth ascription express identical propositions, and, hence, that truth is redundant.
More generally, it is a presupposition of adopting a propositional attitude (and, indeed, of rationality itself) that the adopted tion express identical propositions, and, hence, that truth is redundant.
When we apply these individuation conditions to cognitive acts that are propositions, we generate pairs, or in some cases n-tuples, of representationally identical propositions
that are nevertheless cognitively distinct, because the cognitive demands they place on agents who entertain them are different.