  It should probably not be surprising that Leibniz's explication of the nature of the distinction between necessary and contingent truths can be translated into the terms of contemporary possible-worlds semantics. For Leibniz tells us in On Freedom (De libertate... 1689?) that he first came to think of the nature of possibilia in terms of fictional worlds, worlds that have existence in a somewhat tenuous sense. “But the consideration of possibles, which are not, were not, and will not be, brought me back from this precipice [Spinoza's necessitarianism]. For if there are certain possibles that never exist, then the things that exist, at any rate, are not always necessary, for otherwise it would be impossible for others to exist in their place, and thus, everything that never exists would be impossible.” (A VI iv 1653–54/AG 94) It was only later that he began to conceive of the distinction between necessary and contingent truths in terms of finite and infinite analysis. In the end, then, we can say that the doctrine of infinite analysis is dependent upon the doctrine of the infinity of possible worlds.