  If the only things that truly exist are mind-like entities, monads, then the differences between them must be explicable in terms of mental features. Now, it was stated above that a central feature of Leibniz's account of substance was his claim that substances are endowed with active and passive forces. In his mature metaphysics, Leibniz expresses this view somewhat differently by saying that a substance is active insofar as it has distinct perceptions and passive insofar as it has confused perceptions. Thus, for example, in §49 of the Monadology, Leibniz writes that, “we attribute action to a monad insofar as it has distinct perceptions, and passion, insofar as it has confused perceptions” (G VI 615/AG 219). But, as we learn later in the same work, “Monads all go confusedly to infinity, to the whole; but they are limited and differentiated by the degrees of their distinct perceptions” (G VI 617/AG 221). The fundamental idea here is two-fold: first, activity and passivity are features of the relative clarity and distinctness of the representations of the monad, and, second, insofar as the organic bodies of a particular monad are themselves constituted by monads, they – the monads of the organic body – will have confused perceptions. This chain goes down to the infinitely small, with monads having only very confused and inexact perceptions of the world.