Monad

The ineffable, highest principle, unknowable directly.

Monad, in the sense of "ultimate, indivisible unit," appears very early in the history of Greek philosophy. In the ancient accounts of the doctrines of Pythagoras, it occurs as the name of the unity from which, as from a principle (arche), all number and multiplicity are derived. In the Platonic "Dialogues" it is used in the plural (monades) as a synonym for the Ideas. In Aristotle's "Metaphysics" it occurs as the principle (arche) of number, itself being devoid of quantity, indivisible and unchangeable. The word monad is used by the neo-Platonists to signify the One; for instance, in the letters of the Christian Platonist Synesius, God is described as the Monad of Monads. It occurs both in ancient and medieval philosophy as a synonym for atom, and is a favourite term with such writers as Giordano Bruno, who speak in a rather indefinite manner of the minima, or minutely small substances which constitute all reality. In general, it may be affirmed that while the term atom, not only in its physical, but also in its metaphysical meaning, implies merely corporeal, or material attributes, the monad, as a rule, implies something incorporeal, spiritual, or, at least, vital. The term monad is, however, generally understood in reference to the philosophy of Leibniz, in which the doctrine of monadism occupies a position of paramount importance. In order to understand his doctrine (see LEIBNIZ) on this point, it is necessary to recall that he was actuated by a twofold motive in his attempt to define substance. He wished, in accordance with his general irenic plan, to reconcile the doctrine of the atomists with the scholastic theory of matter and form, and besides he wished to avoid on the one hand the extreme mechanism of Descartes, who taught that all matter is inert; and on the other the monism of Spinoza, who taught that there is but one substance, God. All this he hoped to accomplish by means of his doctrine of monads. Descartes had defined substance in terms of independent existence, and Spinoza was merely inferring what was implicitly contained in Descartes' definition when he concluded that therefore there is only one substance, the supremely independent Being, who is God. Leibniz prefers to define substance in terms of independent action, and thus escapes Descartes' doctrine that matter is by nature inert. At the same time, since the sources of independent action may be manifold, he escapes Spinoza's pantheistic monism. The atomists had maintained the existence of a multiplicity of minute substances, but had invariably drifted into a materialistic denial of the existence of spirits and spiritual forces. The scholastics had rejected this materialistic consequence of atomism and, by so doing, had seemed to put themselves in opposition to the current of modern scientific thought. Leibniz thinks he sees a way to reconcile the atomists with the scholastics. He teaches that all substances are composed of minute particles which, in every case, in the lowest minerals as well as in the highest spiritual beings, are partly material and partly immaterial. Thus, he imagines, the sharp contrast between atomistic materialism and scholastic spiritualism disappears in presence of the doctrine that all differences are merely differences of degree.

Source:The Catholic Encyclopedia 10447b