SUMMA THEOLOGICA. Thomas Aquinas
intelligible perfection from bodies, and through bodies; otherwise they would be united with bodies to no purpose. On the other hand, the higher substances---that is, the angels---are utterly free from bodies, and subsist immaterially and in their own intelligible nature; consequently they attain their intelligible perfection through an intelligible outpouring, whereby they received from God the species of things known, together with their intellectual nature. Hence Augustine says (Gen. ad lit. ii, 8): "The other things which are lower than the angels are so created that they first receive existence in the knowledge of the rational creature, and then in their own nature."
Reply to Objection 1: There are images of creatures in the angel's mind, not, indeed derived from creatures, but from God, Who is the cause of creatures, and in Whom the likenesses of creatures first exist. Hence Augustine says (Gen. ad lit. ii, 8) that, "As the type, according to which the creature is fashioned, is in the Word of God before the creature which is fashioned, so the knowledge of the same type exists first in the intellectual creature, and is afterwards the very fashioning of the creature."
Reply to Objection 2: To go from one extreme to the other it is necessary to pass through the middle. Now the nature of a form in the imagination, which form is without matter but not without material conditions, stands midway between the nature of a form which is in matter, and the nature of a form which is in the intellect by abstraction from matter and from material conditions. Consequently, however powerful the angelic mind might be, it could not reduce material forms to an intelligible condition, except it were first to reduce them to the nature of imagined forms; which is impossible, since the angel has no imagination, as was said above ( Question [54], Article [5]). Even granted that he could abstract intelligible species from material things, yet he would not do so; because he would not need them, for he has connatural intelligible species.
Reply to Objection 3: The angel's knowledge is quite indifferent as to what is near or distant. Nevertheless his local movement is not purposeless on that account: for he is not moved to a place for the purpose of acquiring knowledge, but for the purpose of operation.
Whether the higher angels understand by more universal species than the lower angels?
Objection 1: It would seem that the higher angels do not understand by more universal species than the lower angels. For the universal, seemingly, is what is abstracted from particulars. But angels do not understand by species abstracted from things. Therefore it cannot be said that the species of the angelic intellect are more or less universal.
Objection 2: Further, whatever is known in detail is more perfectly known than what is known generically; because to know anything generically is, in a fashion, midway between potentiality and act. If, therefore, the higher angels know by more universal species than the lower, it follows that the higher have a more imperfect knowledge than the lower; which is not befitting.
Objection 3: Further, the same cannot be the proper type of many. But if the higher angel knows various things by one universal form, which the lower angel knows by several special forms, it follows that the higher angel uses one universal form for knowing various things. Therefore he will not be able to have a proper knowledge of each; which seems unbecoming.
On the contrary, Dionysius says (Coel. Hier. xii) that the higher angels have a more universal knowledge than the lower. And in De Causis it is said that the higher angels have more universal forms.
I answer that, For this reason are some things of a more exalted nature, because they are nearer to and more like unto the first, which is God. Now in God the whole plenitude of intellectual knowledge is contained in one thing, that is to say, in the Divine essence, by which God knows all things. This plenitude of knowledge is found in created intellects in a lower manner, and less simply. Consequently it is necessary for the lower intelligences to know by many forms what God knows by one, and by so many forms the more according as the intellect is lower.
Thus the higher the angel is, by so much the fewer species will he be able to apprehend the whole mass of intelligible objects. Therefore his forms must be more universal; each one of them, as it were, extending to more things. An example of this can in some measure be observed in ourselves. For some people there are who cannot grasp an intelligible truth, unless it be explained to them in every part and detail; this comes of their weakness of intellect: while there are others of stronger intellect, who can grasp many things from few.
Reply to Objection 1: It is accidental to the universal to be abstracted from particulars, in so far as the intellect knowing it derives its knowledge from things. But if there be an intellect which does not derive its knowledge from things, the universal which it knows will not be abstracted from things, but in a measure will be pre-existing to them; either according to the order of causality, as the universal ideas of things are in the Word of God; or at least in the order of nature, as the universal ideas of things are in the angelic mind.
Reply to Objection 2: To know anything universally can be taken in two senses. In one way, on the part of the thing known, namely, that only the universal nature of the thing is known. To know a thing thus is something less perfect: for he would have but an imperfect knowledge of a man who only knew him to be an animal. In another way, on the part of the medium of such knowledge. In this way it is more perfect to know a thing in the universal; for the intellect, which by one universal medium can know each of the things which are properly contained in it, is more perfect than one which cannot.
Reply to Objection 3: The same cannot be the proper and adequate type of several things. But if it be eminent, then it can be taken as the proper type and likeness of many. Just as in man, there is a universal prudence with respect to all the acts of the virtues; which can be taken as the proper type and likeness of that prudence which in the lion leads to acts of magnanimity, and in the fox to acts of wariness; and so on of the rest. The Divine essence, on account of Its eminence, is in like fashion taken as the proper type of each thing contained therein: hence each one is likened to It according to its proper type. The same applies to the universal form which is in the mind of the angel, so that, on account of its excellence, many things can be known through it with a proper knowledge.
OF THE ANGEL'S KNOWLEDGE OF IMMATERIAL THINGS (THREE ARTICLES)
We now inquire into the knowledge of the angels with regard to the objects known by them. We shall treat of their knowledge, first, of immaterial things, secondly of things material. Under the first heading there are three points of inquiry:
(1) Does an angel know himself?
(2) Does one angel know another?
(3) Does the angel know God by his own natural principles?
Whether an angel knows himself?
Objection 1: It would seem that an angel does not know himself. For Dionysius says that "the angels do not know their own powers" (Coel. Hier. vi). But, when the substance is known, the power is known. Therefore an angel does not know his own essence.
Objection 2: Further, an angel is a single substance, otherwise he would not act, since acts belong to single subsistences. But nothing single is intelligible. Therefore, since the angel possesses only knowledge which is intellectual, no angel can know himself.
Objection 3: Further, the intellect is moved by the intelligible object: because, as stated in De Anima iii, 4 understanding is a kind of passion. But nothing is moved