  Inasmuch as it characterizes the universe as composed of a plurality of individual existences, none of which has any genuine causal efficacy over any other, Leibniz’s position shows considerable affinities with Hume’s empiricism. However, while Hume inferred from this the importance of experience, Leibniz instead took this ontology to preclude adventitious knowledge. He thus remained committed on metaphysical grounds to the doctrine of innate ideas. In his rejection of transeunt causation among substances, Leibniz rejected the notion that we can learn new things about the world in the sense of gaining new ideas that do not already exist in our souls. On Leibniz’s account, the temporal coincidence of a certain phenomenon with one’s “learning” of the phenomenon was preestablished at creation in the same way that all monadic states were. Leibniz admitted that it is idiomatically acceptable to speak about acquiring knowledge via the senses. However, he regarded all sensory reports as reducible to, and explicable as, descriptions of logical relations. Leibniz’s theory of knowledge thus relegates the Aristotelian idea of human beings as blank slates who learn through induction to a mere façon de parler. By contrast, he strongly endorsed Plato’s doctrine of recollection to the extent that it locates all knowledge in ideas already residing in the soul. Socrates’s exchange with Meno’s slave boy, argued Leibniz, shows that the soul already possesses the ideas upon which truths about the universe depend, and needs only to be reminded of them.