The touchstone of whether taking something to be true is conviction or mere persuasion is therefore, externally, the possibility of com municating it and finding it to be valid for the reason of every human being to take it to be true; for in that case there is at least a presumption that the ground of the agreement of all judgments, regardless of the difference among the subjects, rests on the common ground, namely the object/ with which they therefore all agree and through which the truth of the judgment is proved.