Gottfried Wilhelm Leibniz's Monadology proposes that the universe consists of simple, indivisible substances called monads, each possessing perception and appetition. These monads, differing in quality, are distinct from one another and represent the entire universe from their unique perspective. Leibniz argues for the existence of God as the necessary substance that grounds the existence and harmony of all monads, establishing a pre-established harmony between the physical and moral realms. This harmony ensures that the actions of monads, governed by final causes, align perfectly with the laws of efficient causes in the physical world. Ultimately, Leibniz's system envisions a divinely ordered universe where all things, both physical and moral, work together in a perfect and preordained system.