Historical Dictionary of Leibniz's Philosophy Quotes

“MONAD. The term monad is a Greek word for “one.” It is prominent in the writings of Plotinus and occurs in the works of various Neo-platonists such as Giordano Bruno and in kabbalistic writers such as Francis Mercury van Helmont. It has been claimed that Leibniz derived the term from one or the other of these, or from another Platonist such as Henry More or Ralph Cudworth. Leibniz, however, had some tendency to concoct Greek-derived neologisms (“theodicy” is the most famous example) and to use existing Greek words for his own purposes. His own use of the word monad seems to have been mostly derived from its use in Greek philosophy, particularly by Pythagoras. Though he must have been aware of its use by other philosophers, he presents it as if it were new to his system, explaining simply that the term meant “one” and never connecting his use of the term with anyone else’s.
Leibniz had long required that substances be genuine unities, in principle indivisible. He began, around 1690, to use the word monad as an alternative for substance or true unity. Monads are conceived in Leibniz’s writings as souls or forms and, in some cases, minds. But they are always united to a body of some kind, even in the case of angels, who need bodies to communicate with one another. Only God, according to Leibniz, is wholly without a body of any kind.
God, angels, and humans are, as rational souls, at the top end of Leibniz’s hierarchy of monads. At the lower end are the souls of the infinitely small creatures that constitute the physical universe.
In Leibniz’s monadology, the higher monads rule over the lower ones. The relation between mind and body is the same as that between a unified center and the collection of monads it brings together and governs. A composite substance such as a human being or an animal consists of a dominant monad and what would, if not for their connection to the dominant monad, be a mere aggregate of monads.
The connection is a causal one and needs to be understood in terms of Leibniz’s theory of causality, that is, the dominant monad will have more clear and distinct perceptions when it produces some “effect” on the others than do those others.”
― Stuart C. Brown, Historical Dictionary of Leibniz's Philosophy

“SUBSTANCE (SUBSTANTIA/SUBSTANCE). A term deriving from Aristotle to refer to the subjects of predication and the objects of scientific inquiry. It became a key term of metaphysics because substances are the fundamental entities of which the universe is constituted. In René Descartes’s philosophy, there are three distinct kinds of substance: God, matter, and minds. In the pantheistic system of Spinoza, on the other hand, there is only one substance, which he refers to as “God-or-Nature.”
Leibniz’s considered view is that there are two fundamentally different kinds of substance: God, who is a pure spirit, and created substances, all of which have bodies. All substances must, according to Leibniz, be capable of action. Only God is pure activity, that is, lacking entirely in passivity; all creatures have some activity and are in varying degrees passive. There is, for Leibniz, a hierarchy of created substances, ranging from creatures close to God, such as angels, to animals that have senses but lack reason, to even more basic corpo-real substances. Humans—capable of reason and therefore made in the image of God—are above animals but lower than angels.
A substance must, according to Leibniz, be a real unity. At one time he seems to have held the view that the unity of corporeal substances was underwritten by their substantial forms. But his later view seems to have been that every substance must be some kind of living thing, with something like perception and something like appetition. He later referred to his simple substances as monads. However, Leibniz seemed also to want to admit complex substances as more than an aggregate of simple substances. He did this by saying that, although there is nothing more to a complex substance than its constituent monads, its unity arises because one of these is the dominant monad.
Leibniz’s theory of substance is the linchpin of his metaphysics.
Each substance, according to Leibniz, is quite unique. He thought that the complete concept of each individual substance contained within itself everything that is true of it. Correspondingly, the nature or essence of each substance was such as to give rise spontaneously to all its phenomena. No substance except God can act on any other substance, nor can it be acted upon by any other substance. The appearance of interaction between substances is to be explained in terms of a preestablished harmony that God has foreordained from the beginning of time.”
― Stuart C. Brown, Historical Dictionary of Leibniz's Philosophy

“Leibniz always asserted the contingency of created substances. That they do not necessarily follow from the concept of the divine substance—as the properties of a triangle follow from its concept— and thus cannot be mere modes of God, is why Leibniz is not a Spinozist or a pantheist. God is transcendent to the world insofar as he is without any limitations—he is infinite with respect to his power, his reason, and his will—hence the created monad is always limited in these respects, “for God could not give the creature everything with-out making of it a God” (Theodicy, §31). On the other hand, monads emanate from God, in that he is their originating causal substance, and they exist in his mind as complete concepts that additionally have been instantiated by his will into actual substances.
In this sense, Leibniz conceives of God as being immanent in every created monad, for each is derived of his substance, reflects his omniscient comprehension of all things in terms of its place in the preestablished harmony, and reflects his will with regard to its very creation: “For one clearly sees that all other substances depend on God, . . . that God is all in all, and that he is intimately united with all creatures” (Discourse on Metaphysics, §32). This immanent aspect of the God–world relationship has led to pantheistic interpretations of Leibniz. However, since he also conceives God to be transcendent to the world, his position is essentially theistic.”
― Stuart C. Brown, Historical Dictionary of Leibniz's Philosophy

“The Discourse on Metaphysics is divided into three main parts. In the first part (§§1–16) Leibniz states and begins to develop two leading principles: that God has chosen to create the most perfect world, and the inesse principle—that it is in the nature of an individual substance to have such a complete concept that from it can be derived everything that is true of that substance. The second part (§§17–22) is concerned with physics and in particular with Cartesian physics, to which Leibniz objects on the ground that its laws of motion are inadequate and because of its exclusion of final causes. The third part (§§23–31) is concerned with the controversy about ideas and with spirits and their relation to God. Leibniz concludes by claiming that the Discourse offers a good account of the relation of the soul to the body, of immortality, and of the special excellence of spirits and their membership of the City of God, their freedom, and their independence of everything except God himself. Finally he commends his principles on the basis of their “utility” in supporting the Christian religion.”
― Stuart C. Brown, Historical Dictionary of Leibniz's Philosophy