In Dialogue de connexione inter verba et res, Leibniz was concerned with the question as to what entity should bear the predicate "is true'. The discussion pertains to the question whether "is true' should be ascribed to "things" or to "thoughts". The property of being true, Leibniz observed, cannot be ascribed to thoughts since a truth, for instance, that the surface described by a fixed length on a plane is a circle does not depend on the fact that it be thought. But the predicate "is true' cannot be ascribed to things either. As Leibniz sees it, whatever can be said to be true can also in principle be called false but, according to Leibniz, it does not make sense to say that things are false. Leibniz takes the solution to consist in ascribing truth to neither the former nor the latter but to what he calls propositio or cogitationes possibile (possible thoughts). Notwithstanding certain definitional qualifications,¹ it is to this Lebnizian idea -which he also ascribes to the Stoics — that Bolzano appeals when he asserts that he was not the first to have put forward the notion of a Satz and sich (cf. Bolzano 1837, §21, 84, 85).