Having treated of the spiritual and of the corporeal creature, we now proceed to treat of man, who is composed of a spiritual and corporeal substance. We shall treat first of the nature of man, and secondly of his origin. Now the theologian considers the nature of man in relation to the soul; but not in relation to the body, except in so far as the body has relation to the soul. Hence the first object of our consideration will be the soul. And since Dionysius 1 says that three things are to be found in spiritual substances - essence, power, and operation - we shall treat first of what belongs to the essence of the soul; secondly, of what belongs to its power; thirdly, of what belongs to its operation.Concerning the first, two points have to be considered; the first is the nature of the soul considered in itself; the second is the union of the soul with the body. Under the first head there are seven points of inquiry.