SUMMA THEOLOGICA. Thomas Aquinas
to understand is not the same as to exist, nor is any operation in him, nor in any other created thing, the same as his existence. Hence the angel's essence is not his power of intelligence: nor is the essence of any creature its power of operation.
Reply to Objection 1: An angel is called "intellect" and "mind," because all his knowledge is intellectual: whereas the knowledge of a soul is partly intellectual and partly sensitive.
Reply to Objection 2: A simple form which is pure act cannot be the subject of accident, because subject is compared to accident as potentiality is to act. God alone is such a form: and of such is Boethius speaking there. But a simple form which is not its own existence, but is compared to it as potentiality is to act, can be the subject of accident; and especially of such accident as follows the species: for such accident belongs to the form---whereas an accident which belongs to the individual, and which does not belong to the whole species, results from the matter, which is the principle of individuation. And such a simple form is an angel.
Reply to Objection 3: The power of matter is a potentiality in regard to substantial being itself, whereas the power of operation regards accidental being. Hence there is no comparison.
Whether there is an active and a passive intellect in an angel?
Objection 1: It would seem that there is both an active and a passive intellect in an angel. The Philosopher says (De Anima iii, text. 17) that, "in the soul, just as in every nature, there is something whereby it can become all things, and there is something whereby it can make all things." But an angel is a kind of nature. Therefore there is an active and a passive intellect in an angel.
Objection 2: Further, the proper function of the passive intellect is to receive; whereas to enlighten is the proper function of the active intellect, as is made clear in De Anima iii, text. 2,3,18. But an angel receives enlightenment from a higher angel, and enlightens a lower one. Therefore there is in him an active and a passive intellect.
On the contrary, The distinction of active and passive intellect in us is in relation to the phantasms, which are compared to the passive intellect as colors to the sight; but to the active intellect as colors to the light, as is clear from De Anima iii, text. 18. But this is not so in the angel. Therefore there is no active and passive intellect in the angel.
I answer that, The necessity for admitting a passive intellect in us is derived from the fact that we understand sometimes only in potentiality, and not actually. Hence there must exist some power, which, previous to the act of understanding, is in potentiality to intelligible things, but which becomes actuated in their regard when it apprehends them, and still more when it reflects upon them. This is the power which is denominated the passive intellect. The necessity for admitting an active intellect is due to this---that the natures of the material things which we understand do not exist outside the soul, as immaterial and actually intelligible, but are only intelligible in potentiality so long as they are outside the soul. Consequently it is necessary that there should be some power capable of rendering such natures actually intelligible: and this power in us is called the active intellect.
But each of these necessities is absent from the angels. They are neither sometimes understanding only in potentiality, with regard to such things as they naturally apprehend; nor, again, are their intelligible in potentiality, but they are actually such; for they first and principally understand immaterial things, as will appear later ( Question [84], Article [7]; Question [85], Article [1]). Therefore there cannot be an active and a passive intellect in them, except equivocally.
Reply to Objection 1: As the words themselves show, the Philosopher understands those two things to be in every nature in which there chances to be generation or making. Knowledge, however, is not generated in the angels, but is present naturally. Hence there is not need for admitting an active and a passive intellect in them.
Reply to Objection 2: It is the function of the active intellect to enlighten, not another intellect, but things which are intelligible in potentiality, in so far as by abstraction it makes them to be actually intelligible. It belongs to the passive intellect to be in potentiality with regard to things which are naturally capable of being known, and sometimes to apprehend them actually. Hence for one angel to enlighten another does not belong to the notion of an active intellect: neither does it belong to the passive intellect for the angel to be enlightened with regard to supernatural mysteries, to the knowledge of which he is sometimes in potentiality. But if anyone wishes to call these by the names of active and passive intellect, he will then be speaking equivocally; and it is not about names that we need trouble.
Whether there is only intellectual knowledge in the angels?
Objection 1: It would seem that the knowledge of the angels is not exclusively intellectual. For Augustine says (De Civ. Dei viii) that in the angels there is "life which understands and feels." Therefore there is a sensitive faculty in them as well.
Objection 2: Further, Isidore says (De Summo Bono) that the angels have learnt many things by experience. But experience comes of many remembrances, as stated in Metaph. i, 1. Consequently they have likewise a power of memory.
Objection 3: Further, Dionysius says (Div. Nom. iv) that there is a sort of "perverted phantasy" in the demons. But phantasy belongs to the imaginative faculty. Therefore the power of the imagination is in the demons; and for the same reason it is in the angels, since they are of the same nature.
On the contrary, Gregory says (Hom. 29 in Ev.), that "man senses in common with the brutes, and understands with the angels."
I answer that, In our soul there are certain powers whose operations are exercised by corporeal organs; such powers are acts of sundry parts of the body, as sight of the eye, and hearing of the ear. There are some other powers of the soul whose operations are not performed through bodily organs, as intellect and will: these are not acts of any parts of the body. Now the angels have no bodies naturally joined to them, as is manifest from what has been said already ( Question [51], Article [1]). Hence of the soul's powers only intellect and will can belong to them.
The Commentator (Metaph. xii) says the same thing, namely, that the separated substances are divided into intellect and will. And it is in keeping with the order of the universe for the highest intellectual creature to be entirely intelligent; and not in part, as is our soul. For this reason the angels are called "intellects" and "minds," as was said above ( Article [3], ad 1).
A twofold answer can be returned to the contrary objections. First, it may be replied that those authorities are speaking according to the opinion of such men as contended that angels and demons have bodies naturally united to them. Augustine often makes use of this opinion in his books, although he does not mean to assert it; hence he says (De Civ. Dei xxi) that "such an inquiry does not call for much labor." Secondly, it may be said that such authorities and the like are to be understood by way of similitude. Because, since sense has a sure apprehension of its proper sensible object, it is a common usage of speech, when he understands something for certain, to say that we "sense it." And hence it is that we use the word "sentence." Experience can be attributed to the angels according to the likeness of the things known, although not by likeness of the faculty knowing them. We have experience when we know single objects through the senses: the angels likewise know single objects, as we shall show ( Question [57], Article [2]), yet not through the senses. But memory can be allowed in the angels, according as Augustine (De Trin. x) puts it in the mind; although it cannot belong to them in so far as it is a part of the sensitive soul. In like fashion