Although every monad is active, it is not entirely active. There is, as we have already seen, an infinite scale of substances; and since substance is equivalent to activity, this is saying that there is an infinite scale of activities. God alone is _purus actus_, absolute energy, untouched by passivity or receptivity. Every other being has the element of incompleteness, of inadequacy; it does not completely represent the universe. In this passivity consists its finitude, so that Leibniz says that not even God himself could deprive monads of it, for this would be to make them equal to himself. In this passivity, incompleteness, or finitude, consists what we call matter. Leibniz says that he can understand what Plato meant when he called matter something essentially imperfect and transitory. Every finite monad is a union of two principles,--those of activity and of passivity. "I do not admit," says Leibniz, "that there are souls existing simply by themselves, or that there are created spirits detached from all body. God alone is above all matter, since he is its author; creatures freed from matter would be at the same time detached from the universal connection of things, and, as it were, deserters from the general order." And again, "Beings have a nature which is both active and passive; _that is_, material and immaterial." And again, he says that every created monad requires both an entelechy, or principle of activity, and matter. "Matter is essential to any entelechy, and can never be separated from it, since matter _completes_ it." In short, the term "monad" is equivalent to the term "entelechy" only when applied to God. In every other monad, the entelechy, or energy, is but one factor. "Matter, or primitive passive power, completes the entelechy, or primitive active power, so that it becomes a perfect substance, or monad." On the other hand, of course, matter, as the passive principle, is a mere potentiality or abstraction, considered in itself. It is real only in its union with the active principle. Matter, he says, "cannot exist without immaterial substances." "To every particular portion of matter belongs a particular _form_; that is, a soul, a spirit." To this element of matter, considered as an abstraction, in its distinction from soul, Leibniz, following the scholastics, and ultimately Aristotle, gives the name, "first" or "bare" matter. The same influence is seen in the fact that he opposes this element of matter to "form," or the active principle.