Summa Theologica

The previous question established that angels are incorporeal. However, since scripture tells of angels appearing to human beings, Aquinas must address the question of whether angels somehow use, or unite themselves to, bodies in order to carry out their mission. He concludes that angels sometimes assume bodies, for the purpose of conversing with human beings in a form familiar to them, and also (in the Old Testament) to give a foretaste of the Incarnation, in which the Son of God took on a human body. However, these bodies are simply “assumed” and do not function as human bodies do. In this way, the angels act as agents revealing to us spiritual things in a human form. 

Angels do not occupy space as physical bodies do. They instead apply their angelic power in particular places. 

Aquinas addresses the question of how angels move in space and time. He concludes that angels can move from point to point without necessarily passing through the intervening points. 

Here Aquinas seeks to answer the question of how angels know things. Aquinas particularly wishes distinguish between angels’ mode of knowing and the modes of knowing that are proper to God and to human beings. Angels are pure intellect and mind, because their knowledge is purely intellectual, without the sense component that human beings have. However, angels’ power of knowing is not the same as their substance or their being, in contrast to God, in whom these things are identical.

Aquinas has established that knowledge is not the essence of angels. Unlike God, they do not have all knowledge within themselves. Unlike us, they do not need to get their knowledge externally, through the senses. Angels instead receive their knowledge as a sort of direct illumination from God, so that their knowledge is connatural (innate) to them.

Aquinas asks whether angels can know themselves, each other, and God.

He answers in the affirmative in all three cases.

In explaining angels’ knowledge of God, Aquinas distinguishes between three kinds of knowledge of God. First is to know God as he is in his essence. For humans, this will happen only in the next life. The second way is to know God as he is reflected in creatures—an imperfect knowledge—and this is how we know him in this life. The angels’ knowledge of God is midway between these two kinds of knowledge, insofar as their nature is itself the “mirror” that reflects the image of God.

Thus, while we get our knowledge of God indirectly, through created things, angels’ knowledge of God is imprinted directly on their natures. 

By definition, angels’ knowledge is more perfect than ours, but still not as perfect as God’s.

Angels know material things through their own essence, not through sense experience as we do. Material things in a sense exist in the angels in a similar way to how they pre-exist in God. Angels know singular things like individual human beings, and not only universals; otherwise they would not be able to carry out their missions. While we know things by sense knowledge plus intellect, angels know things by pure intellect.

Angels can know future events, not in themselves (this power belongs only to God), but by seeing causes and foreseeing the consequences. Angels are able to discern secret thoughts of other beings by seeing outward effects; indeed, angels can see these things with even greater subtlety than we can. However, only God can read hidden thoughts.

Finally, angels do not know divine mysteries such as the Incarnation or Redemption innately. These are revealed to them by God to the extent that they need to know them to carry out their mission.

Aquinas seeks to distinguish more clearly the way angels know things from the way humans know things.

Angels grasp things in their simple essence, through direct intuition. They do not have to go through a complex process of analysis and reasoning as we do. This is because angels have no potentiality. As a consequence, angels are able to grasp complex groups of ideas as a single unity. Moreover, angels are incapable of erring in their knowledge. The exception to this is the demons or fallen angels, and this idea will be developed later on. 

Will is the inclination toward the universal good itself, and part of the dignity of human nature; therefore, since angels’ nature is higher than man’s, they must necessarily have will.

One way to show that angels have will is to look at the types of appetite in creatures. Inanimate bodies, plants, and animals have a natural inclination toward their good and perfection. Human beings desire certain particular goods through their sense knowledge (e.g., desiring something sweet).

Angels have will because it is a faculty of the intellect and angels are purely intellectual beings. Angels also necessarily have free choice; they are not programmed to choose certain things.

Angels differ from humans in that they do not have what Aquinas terms the irascible or concupiscent appetite. The concupiscent appetite has to do with our inclination to things that are attractive. The irascible appetite has to do with achieving difficult objectives and overcoming obstacles to attaining the things we desire. Both appetites belong to the sensitive faculty, which does not exist in angels, since they are purely spiritual and intellectual.

Angels exercise various virtues such as temperance and fortitude, not in the same way that we do but rather in a spiritual way pertaining to their carrying out God’s plan. 

Every being has an inclination conforming to its nature. In the case of the angels, this is “intellectual love.” 

In addition to this inborn, natural love, angels also have the “love of choice,” that is, the faculty of choosing freely to love particular things. This is similar in human beings. We have a natural love which is directed to our final end (knowing and loving God), but also a love of choice by which we choose particular things that will help achieve that end.

Since it is natural for every creature to love that which is one with itself, it follows that angels love each other with a natural love. However, angels love God more than they love themselves. This follows from the natural inclination that things have to sacrifice the lesser to the greater good.

Aquinas examines how angels were created, arguing against the notions that angels coeternally exist with God and were created before the material world. He affirms that God created angels along with the material world, and they are neither his coequals nor part of a separate world or universe. 

Happiness (beatitude) is the ultimate goal and perfection of a rational or intellectual being. There are two degrees of beatitude for human beings:

1.  contemplating God in this life, by which we consider God as First Cause of all things

2.  the Beatific Vision, or seeing God face to face in the life to come.

The first is naturally open to us, while the second requires the grace of God to achieve. Angels have the first kind of happiness built into them—although they have a direct intuition of God as First Cause and do not need to reason it out. As for the second, they, like us, need the grace of God to achieve it. 

In the Fall of the Angels, the highest angel, Lucifer, rebelled against God. This is considered a parallel to the Fall of Man. The angels who joined Lucifer’s rebellion became the demons.

As created beings endowed with free choice of the will, the angels were capable of sin. However, since they are incorporeal, angels could only commit the spiritual sins of pride and envy. The rebellion of Lucifer was a sin of pride, of desiring to be like God. After this first sin, the fallen angels became envious of human beings because of God’s designs for them. Hence, the fallen angels (demons) do everything in their power to hinder man’s progress toward God.

The sin of the fallen angels was freely chosen and not the result of some natural, ingrained evil. Lucifer’s sin led other angels to sin. The wicked angels believed that they could obtain a kind of advantage by being subject to Lucifer instead of God. Those angels who remained faithful outnumbered those who fell.

This question deals with the aftermath of the fall of the angels. While human beings can change the course of their actions, the will of the angels’ is fixed and immovable. Thus, the “will of the good angels is confirmed in good” and “the will of the demons is obstinate in evil” (336). Demons are being punished now; their punishment will not have to wait for the Final Judgment. Likewise, the holy angels are presently enjoying their glory. This glory is not lessened in visiting us on earth.