Saint Thomas Aquinas and Angels
The fact that Saint Thomas is called the Angelic Doctor is not due to his cherubic physique alone. Rather, he spent a considerable amount of space in the Summa Theologiae, among other places, discussing the nature, activities and moral state of angels. Often, he would use the nature of the angels to illuminate the nature of human cognition by referring to angels as the extreme of what is possible for an intellectual nature to be. He also discusses them for their own sakes, but all the time keeping his remarks bound by the limits of the definitive teaching of Sacred Scripture, and by the rigors of consistent thinking.
What are angels and how do we know of their existence?
Thomas gives an argument that the perfection of the universe requires the existence of intellectual creatures. Since God intends the good for His creation, he intends that it be like Himself. And since an effect is most like its cause when it shares with it the feature whereby it was caused, God’s creation must contain something with intellect and will since that is how God creates, i.e. by first knowing it and loving it into being.
Hence the perfection of the universe requires that there should be intellectual creatures. Now to understand cannot be the action of a body, nor of any corporeal power…. Hence the perfection of the universe requires the existence of an incorporeal creature.ST Ia 50, 1
However, since humans are intellectual creatures, as he indicates at the end of this very argument, the need for some intellectual creatures is not sufficient to give us knowledge of the existence of purely intellectual creatures which the angels are.
Since Sacred Scripture does speak definitively about the existence of angels, it belongs to Sacred Doctrine, i.e. theology, to treat of angels in a truly scientific manner. The divine science has the intellectual tools (faith in Scripture) to establish both the fact of angels and their nature (ST Ia, 1, 3). Having accepted on faith that angels exist, or taking their existence to be purely hypothetical, one can still draw certain philosophical conclusions about their nature. Thomas’ words in the Summa are an excellent guide for how one can think clearly about the angelic hosts.
For Thomas, given that angels are intellectual creatures, they must be pure spirit, i.e. self-subsistent forms. They are completely incorporeal; they are in no way material, and have no bodies of any kind.(Ia 50, 2) Some, Franciscan theologians of the 13th century (St. Bonaventure among them), believed that angels, like everything other than God, were composed of matter and form. These thinkers, holders of the theory of “universal hylomorphism” as it was called, believed that, whereas sensible things in the world around us had corporeal matter, angels had spiritual matter. For Aquinas, the idea of spiritual matter was a complete confusion. If a thing is spiritual, then, insofar as it is spiritual, it is not material in the sense that it is not composed of matter. (Even though humans are both spiritual and material, their spiritual soul is not composed of spiritual matter and form as the Franciscan believed.)
(The view of universal hylemorphism lives on today, ironically enough, in the truly physicalist theory in the philosophy of mind called functionalism, insofar as functionalists (such as Hilary Putnam) claim that if there were disembodied spirits, their mental states would be functional states. In order for such a statement to be true, such spirits would have to have parts made of spiritual matter which interacted in the way that functional theory specifies.)
Angels are not merely ethereal, vaporous kinds of material things since they are not material things at all. Nor are they the souls of dead humans. (The state of human souls after death is an interesting topic with which Thomas deals, but it will have to await separate treatment.) It is natural for humans to know through their bodies, and for their souls to enliven their bodies. Angels, on the other hand, are pure intellects and not naturally united to a body (Ia 51, 1). Consequently, angels know things in a way that is (almost) completely alien to how humans act and know. This is sufficient to show that angels are not separated souls. Thomas, then, has ample philosophical reasons to resist identifying angels with the souls of our deceased relatives and friends.
The Bodies of Angels
What is somewhat surprising is that, even though angels are completely immaterial creatures, Thomas believes, given what is said about them in Scripture, that they sometimes assumed bodies.
Yet divine Scripture from time to time introduces angels so apparent as to be seen commonly by all…. From all this it is clearly shown that such apparitions were beheld by bodily vision, where the reality seen exists outside the person beholding it, and can accordingly be seen by all.
Thomas takes it to be a philosophical principle that a thing must be physical in order to be seen by bodily vision: “Now by such vision only a body can be beheld.” He then draws the conclusion that the body, which those in Scripture see an angel to have, must have been assumed, i.e. not be their own, but borrowed, as it were.
Consequently, since all angels are not bodies, nor have they bodies naturally united with them, as is clear from what has been said, it follows that angels sometimes assume bodies.ST Ia 51,2
The body which one sees to belong to an angel cannot belong properly to it, since angels are perfect intellects (Ia 50,1), and intellectual knowledge cannot be accomplished by a bodily nature (Ia 51,1). So if one grants for theological reasons (i.e. on the authority of scripture or for the sake of the perfection of God’s creation) that angels exist and appear, then it follows as a consequence that they manipulate matter in order to appear that they have bodies: “…by divine power sensible bodies are so fashioned by angels as to fittingly represent the intelligible properties of an angel”(Ia 51, 2 ad 2).
Angelic Bodies Are Not Living
Nevertheless, angels are not properly said to be alive while they are assuming their bodies. For in order for the body assumed by an angel to be living, the angel’s union with it would have to be as the body’s form, and such a union would be natural, since life is a natural activity for the thing that is alive. The fact that the body which an angel assumes is not alive implies that it does not, strictly speaking, see or hear or taste since these are functions of living things. An angel, then, does not receive sensible forms, nor derive any enjoyment from such a reception as humans do (Ia 51, 3 ad 2). Likewise, angels do not engage in sex while assuming their bodies (cf Ia 51, 3 ad 6) It is interesting to note that Aquinas felt the need to consider six objections (a somewhat large number for the Summa) in Question 51, a. 3; apparently, there were many in his day, as in ours, who thought it made sense that angels could live a human life while assuming bodies.
Purpose of Angelic Appearances
Aquinas in a few passages indicates what the purpose of angelic appearances is. In Ia 51, 2 ad 1 he says that the purpose of angelic conversation is to “give evidence of that intellectual companionship which men expect to have with them in the life to come,” and in the Old Testament, “as a figurative indication that the Word of God would take a human body.” In Ia 51, 3 ad 1 & 2 he claims that angels appear so that spiritual properties and works may be manifested more fittingly than by men. In all cases, the purpose of the appearances of angels is to inform humankind of divine realities, and so to lead people to God.
Hence Angels propose the intelligible truth to men under the likeness of sensible things and strengthen the human mind by an intellectual operation. In this twofold action consists angelic illumination of men. By adding to the human understanding to pierce the mysteries of being, the pure intelligences enable it to derive greater truth from the species abstracted from sensible things. Thus men rise with angelic assistance to a more perfect knowledge of God drawn from a knowledge of his creation (p. 322).
Angelic power is truly cosmic in its range according to the Thomistic account. On every level in the hierarchy of created being, angelic agency has a proper function to fulfill in accordance with the designs of divine wisdom. Although creativity cannot belong to them [since only God can create from nothing] angels are nevertheless the chief ministers employed by God in the governance of the universe, in securing His own glory and in distributing His goodness to all creation. Everywhere there is a gracious adaptation to the capacity of the various orders of nature to participate in the divine likeness which all things desire in their proper way (p. 328).James Collins, The Thomistic Philosophy of the Angels, a Dissertation, (Washington, D.C.: Catholic University Press, 1947)
Dangers Associated with Angels
Although Thomas believes that angels, like everything else in creation, actually do contribute to the greater glorification of God, he does recognize some dangers. In Ia 61, 1 ad 1 he responds to the objection that, because angels are not mentioned in the Biblical account of creation, God did not create them. He says God created everything that exists, and the fact that angels are not mentioned in Genesis 1 is no indication that God did not create them. Aquinas attributes their omission to the danger posed by knowing about them and too much attention being paid to them. Indeed, it seems as though the Israelites in the Old Testament were in constant danger of worshiping something other than God as God. So rather than mention them, Aquinas says that Moses sought to remove an occasion of idolatry from the people. This shows that there is a danger in focusing too much on angels as opposed to God without whom they would not exist, and without whom their existence is unintelligible. Angels are, after all, messengers, and one ought not attend too much to the messenger while neglecting the message, which is God’s Word.
Moreover, Aquinas also warns us that not all angels are good. Indeed, some remarkable things that are apparently done by magicians or psychics, may in fact be due to the influence of bad angels.(cf Summa Contra Gentiles III, c.104ff.)