Leibniz's Discourse On Metaphysics Summary

In order to understand Leibniz’ writing in this passage, one must comprehend the definitions he has set forth in previous sections of his writing. To begin, a monad is a similar concept to an atom, though the two differ in some respects. Leibniz even references atoms in his first discussions of monads, where he says that “monads are the true atoms of nature” (§ 3, p. 275). He says that these monads are simple, which means they are whole in and of themselves; they do not consist of parts but instead form composites, which are collections of monads brought together (§§ 1-2, p. 275). Monads are indivisible and the smallest pieces of matter (§ 3, p. 275); they are infinite with no clear beginning or end except in the case of divine
Because of this, they “express the whole universe” since a single substance might one day be part of one body, e.g., a skin cell, and the next day part of another, e.g., the cell is eaten by another organism, breaks down, and through biological processes becomes part of the new body (“Discourse on Metaphysics,” § 34, p. 245). This past writing of Leibniz’ has likely influenced what he wrote in “Monadology,” for this definition of a substance is very similar to his idea of a monad; it is also intrinsically linked to the idea that all things are plenums, including bodies, and that all living bodies are made up of infinite parts (§§ 64-65, p. 281). This is evident by his repeated use of the phrase “express the whole universe” (§ 65, p. 281). If viewed from another perspective, one might say that since every bit of matter—or substance—is infinite (Spinoza, Pr. 8, p. 146), and since infinite matter cannot be divided (Spinoza, Pr. 13, p. 149), then each infinite part of infinite bodies must necessarily be God (Spinoza, Pr. 14, p. 149). Leibniz’ own view is quite similar; he says that since each piece of matter reflects the universe, souls are necessarily akin to “living mirrors … of the universe of creatures” and to “divinity itself” (§ 83, p.