The Angelic Doctor’s Angelic Doctrine

Thomas Aquinas is often known as the Angelic Doctor. Explanations for this title are varied, with the most common being that the title was meant to convey something about the subtlety of his reasoning on theological matters. Others have said he simply wrote a lot about angels.

It is true that he wrote a lot about angels, but – then again – he wrote a lot about a lot of things: something like 8 million words on theology. Regarding angels in particular, he produced a score of questions in his Summa Theologiae, a treatise on spiritual creatures, another on separated substances, as well as numerous reflections in various disputations and quodlibets. Such work has made him among the most celebrated writers on angelology in the Middle Ages – the roughly 1000-year period between Augustine and Luther.

For Thomas, and for medieval theology generally, angelology was largely a bridge doctrine – a conceptual link between the pure and ineffable nature of God and the natures of lower, corporeal creatures like humans, squirrels, or rutabagas. It was also an opportunity to put certain metaphysical tools through the paces, since revealed truths about angels could reveal weaknesses in certain philosophical conceptions of substance, will, action, intellect and so-on. Hence, the metaphysical labor of Aquinas is simply an attempt to sketch out a plausible structure for dividing the traditional hierarchy of being in terms of the metaphysical resources of Aristotle, which had only recently entered the Christian West.

Yet, medieval teaching on the angels, and Thomas’ in particular, is often met with some suspicion as being fundamentally speculative, inconsequential, or navel-gazing. Some of this criticism is well-earned, after all: the medieval theologians did not know that Pseudo-Dionysius was Pseudo-Dionysius. Nevertheless, evangelicals tend to paint the period and the purpose of angelology in medieval dogmatics with too broad a brush. It is important that we understand before we judge.

While some of the questions that would have concerned Aquinas have very little interest for contemporary non-specialists, the basic picture that he paints of angels would be – in broad outline – what most evangelicals have heard in church. Angels are spirit creatures, who move about largely unseen to do God’s will. What a rehearsal of Aquinas’ views on this subject does for us, then, is provide an opportunity to see how he expresses something to which we ought to be strongly committed, namely, that angels aren’t human and that they aren’t God either. They are higher than we are in the hierarchy of being, yet they are still created and personal spirits – much like our souls would be if we weren’t human. In reflecting on his writing, we find that the philosophical resources to which he had access provide a rich and useful means of expositing Christian insights derived from Sacred Scripture. Along the way, such historical study allows us to see how our forebears critically assimilated such resources, which opens their projects both to celebration and critique.

How are angels different from us?

Very few definitive statements about the angelic nature have been made in ecclesiastical history, partly because there has not been tremendous controversy about the basic contours of their nature and partly because the biblical witness on angels is limited. This observation is especially important in the study of the history of angelology, which defined angels often in oblique and polemical contexts. On the one hand, theologians have wanted to preserve the transcendence of God. The rationale for this desire should be obvious. On the other hand, they have wanted to place the angelic nature above the human nature. This desire has been often driven by exegesis, such as the intra-testamental exegesis found in the book of Hebrews. Although these competing desires led to some discrepancies in their terminology (some of which pass on to deeper disagreements), there are some consistent themes among significant historical theologians about angels. Certainly, one of those themes has been the intuitive principle that humans and angels are different kinds of beings, and that this difference was discoverable in the incorporeality of the angelic nature. In other words, angels are different from us mostly because they don’t have bodies. Angels are different from us mostly because they don’t have bodies. Click To Tweet

This principle – derived from Scripture – is one area in which Thomas Aquinas’ reflection on the angels serves us well. Understanding the nature of his reflection requires that we begin with an insight about the Bible’s testimony. The scriptures do not tell us everything that we might want to know about angels. The biblical authors don’t even discuss angels, so much as they mention them with an assumed familiarity when it is appropriate to whatever topic they are being led by the Spirit to discuss. In fact, the lack of information is one reason that most modern books on angels are full of breathless anecdotes instead of exegesis or attention to Christian history. A notable example of the lack of information in the biblical witness is the fact that angels – although spirit creatures – at times appear indistinguishable from human beings. Historically, the question about how this was possible was discussed under the label of the “angelic assumption of the body.”

Despite the paucity of biblical data (indeed, perhaps because of it), Christian theological speculation about this doctrine has been a constituent feature of metaphysical questioning since the second century. In assessing what Thomas adds to the conversation, my goal is not to say that Thomas has found “the” answer – for beyond some key and necessary guardrails for Christian metaphysics – there are potentially other ways of explaining the assumption of the body. Instead, my goal is to show that his critically assimilated Aristotelian conception of substance and being provides a helpful regulative explanation. In fact, by embracing some details of this explanation, we find ourselves in a better position to defend the key distinction of the biblical worldview, which is the distinction between the Creator and creation. I explain this to my students as the notion that there is God and there is everything else.

The Scriptural criteria that must be satisfied on this question build from this first distinction to a second one, namely, that angels are not humans. Any successful metaphysical account of angels must at minimum be able to describe how a non-corporeal creature can appear bodily to such an extent that he is mistaken for an embodied creature. Aquinas’ angelology can help make sense of this problem. It will be clear, I trust, that this analysis is rooted in an attempt to explain a question raised by the discussion of angels in the Bible and not merely some perverse speculative urge.

The hierarchy of reality

In the hierarchy of reality, man is lower than the angels and God is above them (Ps. 8; Heb. 2:5-9). Aquinas attempts to elucidate this distinction using the philosophical concepts of being, essence, matter, and form. Explaining these distinctions both allows us to say something about our biblical question, but also serves to tighten the bridge between the theological loci on either side of angelology in the traditional pattern, namely, the doctrine of God and the doctrine of humanity.

First, how, if angels are spirits (Heb. 1:14), are distinct from God who is spirit (John 4:24)? In comparison to us, angels are simple creatures because they don’t have bodies. However, we know that they are not metaphysically simple per se, because they are creatures. Only God is truly simple. What distinguishes them?

For Thomas, the distinction is found principally in the difference between the “being” of an angel and the “essence” of an angel. Roughly, this is a distinction between whatever it is that individuates a particular angel and that other thing – whatever it is – that makes him an angel as opposed to a human or a rutabaga. In contrast to his creatures, God is his essence. He isn’t a fellow who happened to have “Godness.” He alone is God. Hence, he is truly simple. Angels – though lacking the composition between soul and body found in human persons – still have a composition between what they are and their own existence. This is a consequence of their contingency – their creatureliness (see ST I.61.1, based on ST I.3.4).Although angels are not complex in comparison to humans, they are complex compared to God. Click To Tweet

The “angelness” of a particular angel – say, Michael – belongs only to Michael according to Aquinas. Since he has no body, his “form” is what distinguishes him from the other angels. Yet, we can also speak of the nature that is “shared” among all the creatures that are called “angels.” This fact is the reason, of course, that the angels can all be called “angels.” So, although angels are not complex in comparison to humans, they are complex compared to God. This is because they are creatures. Thomas uses an Aristotelian distinction here to describe a difference between God and spiritual creatures – a distinction to which we were antecedently committed from the truths of Holy Scripture.

But what makes angels different than humans?

The reason angels are simple compared to us is that they do not have bodies: they are purely spiritual creatures (Heb. 1:14; ST I.50.1). Humans, by contrast, are bodily sorts of beings, made from the dust of earth (Gen. 2:7; Luke 24:38). Hence, we have a thing that the angels do not: the bags-of-meat that we walk around in. In fact, understanding the distinction between angels and humans in terms of the distinction between matter and form assists us by preventing a common mistake in theological anthropology. That is the mistake of thinking of human persons as souls that just happen to have bodies. That is simply not the way that the scripture talks about us.

Although there are quite powerful philosophical arguments that we are identical with our immaterial souls, the strongest of these – the Meditations of Descartes – expressly sets the scripture to one side as a part of the project. Thomas’ account does not do that. Instead, he attempts to explain the soul-body unity that we find attested in scripture (and, frankly, in our experience) by using the Aristotelian categories of matter and form. So, in the way that “existence” and “essence” offered him a clear way to distinguish between God and spiritual creatures, “matter” and “form” allows him a way to distinguish between angels and men.

The Soul: The Form of the Body

Thomas says that the soul is the form of the body. The soul is what makes the body a body. Click To Tweet Thomas says that the soul is the form of the body (ST I.76.5). What this means in his parlance is that the soul is what makes the body a body. In particular, your soul is what makes your body your body. He takes this metaphysical set of distinctions from Aristotle in De Anima. However, although we know that angels are not bodily creatures, they do at times appear to have bodies in Scripture. As Thomas says, “Holy Scripture occasionally introduces angels who are so obvious that they are seen by all” (ST I.51.2).

He has in mind examples such as the angels of Genesis 18 and 19. But, because we know that the angels and humans are different kinds, the relationship that the angels have to these bodies is not like the relationship that your soul has to your body (Heb. 2:14-17). Rather, the relationship between an angel and the rarefied body it “assumes” is an extrinsic relationship produced by divine power for God’s purpose is sending a message (ST I.50.2). In contrast, your relationship to your body is intrinsic and is based on the way God made you a human person.

These distinctions, which he works out in some careful detail, capture the tradition of reflection to his point in history, as found in John Damascene (De Fide Orthodoxa), Gregory Nazianzen (Carmina 1.1.7), Augustine (Enchiridion 59), Jerome (Contra Jovinianus 2.27). They are reflected without critical explanation also in Luther (Table Talk 565) and Calvin (Institutes 1.14.5). Hence, the reflections are an important part of the history of the doctrine.

Thomas’ ability to work out these distinctions shows a willingness to mine the philosophical resources of his time for vocabulary that helps to explain the witness of Scripture. Obviously, this is a process that requires the critical assimilation of those resources as well as the rejection of some features of a philosophical system. Nevertheless, his angelology contains important examples of the kind of theological work that can be of both historical and contemporary value.