_b._ A higher kind of substance, according to Aristotle (Metaph. IX. 2; VII. 7; XII. 3), is that into which activity enters, which already contains that which is about to be. This is understanding, absolutely determined, whose content is the aim which it realizes through its activity, not merely changing as does the sensuous form. For the soul is essentially actuality, a general determination which posits itself; not only formal activity, whose content comes from somewhere else. But while the active posits its content in reality, this content yet remains the same; there is an activity present which is different from matter, although substance and activity are allied. Thus here we still have a matter which understanding demands as its hypothesis. The two extremes are matter as potentiality, and thought as efficiency: the former is the passive universal, and the latter the active universal; in sensuous substance the active is, on the contrary, still quite different from matter. In these two moments themselves change does not take place, for they are the implicit universal in opposed forms. _c._ The highest point is, however, that in which potentiality, activity and actuality are united; the absolute substance which Aristotle (Metaph. XII. 6, 7; IX. 8), defines in general as being the absolute (ἀϊδιον), the unmoved, which yet at the same time moves, and whose essence is pure activity, without having matter. For matter as such is passive and affected by change, consequently it is not simply one with the pure activity of this substance. Here as elsewhere we certainly see an instance of merely denying a predicate, without saying what its truth is; but matter is nothing else than that moment of unmoved Being. If in later times it has seemed something new to define absolute Being as pure activity, we see that this arises from ignorance as to the Aristotelian conception. But the Schoolmen rightly looked upon this as the definition of God, since they define God as _actus purus_; and higher idealism than this there is none. We may also express this as follows: God is the Substance which in its potentiality has reality also unseparated from it; therein potentiality is not distinguished from form, since it produces from itself the determinations of its content. In this Aristotle breaks away from Plato, and for this reason controverts number, the Idea, and the universal, because if this, as inert, is not defined as identical with activity, there is no movement. Plato’s inert Ideas and numbers thus bring nothing into reality; but far different is the case with the Absolute of Aristotle, which in its quiescence is at the same time absolute activity.