5. An attribute may characterize a thing by reference to its effects or works, not in the sense that the thing or author of the effect has acquired a character by reason of the product, like carpenter, painter, blacksmith, but merely in the sense that he is the one who made a particular thing. An attribute of this kind is far removed from the essence of the thing so characterized by it; and hence we may apply it to God, provided we remember that the varied effects need not be produced by different elements in the agent, but are all done by the one essence. Those who believe in attributes divide them into two classes, and number the following four as _essential_ attributes, not derived from God's effects like "creator," which denotes God's relation to his work, since God did not create himself. The four essential attributes about which all agree are, living, powerful, wise, possessed of will. Now if by wise is meant God's knowledge of himself, there might be some reason for calling it an essential attribute; though in that case it implies "living," and there is no need of two. But they refer the attribute wise to God's knowledge of the world, and then there is no reason for calling it an essential attribute any more than the word "creator," for example. In the same way "powerful" and "having will" cannot refer to himself, but to his actions. We therefore hold that just as we do not say that there is something additional in his essence by which he created the heavens, something else with which he created the elements, and a third with which he created the Intelligences, so we do not say that he has one attribute with which he exercises power, another with which he wills, a third with which he knows, and so on, but his essence is simple and one.[277]