In addition to Aquinas’s treatment of angels as metaphysical curiosities, Howard Kainz also speaks of an important anthropological dimension to Thomas’s angelology. Kainz begins by making the point (especially apropos to our interest in Tolkien) that it is “profitable for us to discuss the significance of the angels, in terms of their mythical content,” by which he means the “subjective relevance” of the angelic beings, first, as “projections” of an idealized human existence, secondly, as “external reflections” of a “hierarchy of spiritual values, and thirdly, as “models” for human political ideals such as equality. In other words, in addition to the theoretical significance of the question of their actual existence, reflection on angels was understood to provide important insights into human beings as their immediate yet subordinate neighbors in the hierarchy of being.
Consistent with this anthropological perspective on Thomas’s angelology is the following remark by one of Tolkien’s own mentors in the ways of fairy-land, G.K. Chesterton. In his biography of St. Thomas he writes:
St. Thomas really was rather specially interested in the nature of Angels, for the same reason that made him even more interested in the nature of Men. It was a part of that strong personal interest in things subordinate and semidependent, which runs through his whole system: a hierarchy of higher and lower liberties. He was interested in the problem of the Angel, as he was interested in the problem of the Man, because it was a problem; and especially because it was a problem of an intermediate creature. I do not pretend to deal here with this mysterious quality, as he conceives it to exist in that inscrutable intellectual being, who is less than God but more than Man. But it was this quality of a link in the chain, or a rung in the ladder, which mainly concerned the theologian, in developing his own particular theory of degrees. Above all, it is this which chiefly moves him, when he finds so fascinating the central mystery of Man. And for him the point is always that Man is not a balloon going up into the sky, nor a mole burrowing merely in the earth; but rather a thing like a tree, whose roots are fed from the earth, while its highest branches seem to rise almost to the stars.
As I hope to show in some follow-up posts, it is to this same scholastic tradition of doing anthropology by proxy—that is, of studying man by studying that which is not man and yet nearest to him (man’s “other”)—that both Tolkien’s fictional angels and his Elves may instructively be seen to belong.
 Chesterton, St. Thomas Aquinas: “The Dumb Ox,” 164. David Keck gives a similar account of the anthropological motive involved not only in Thomas’s but in medieval speculation over angels generally when he writes: “Of all God’s creatures, human beings are nearest to the angels, and angelology thus promises to illuminate anthropology. In the modern world, the impulse to learn about human nature from closely related beings has shifted subjects from seraphim to simians. Whereas modern scientists study the origins of the apes to uncover clues about humanity, medieval theologians investigated angels.” Keck, Angels and Angelology in the Middle Ages, 16. Collins makes the same point in his study on Thomas’s angelology: “The unity of the source of all being and the analogical similarity of all things guarantee that a knowledge of each grade will shed some further light upon what is below and what is above it in the hierarchy of reality. For the better understanding of God and the creative process, we can turn to that order of being which provides the most intimate created similitude of the first intelligent and free Agent. On the other hand, while it is true (as Pascal observes) that man is neither brute nor angel, still the consideration of him from the perspective of the angel to whom he is inferior as well as of the brute which he surpasses does enable us to determine more accurately his proper stature. Both natural theology and philosophical anthropology may profit by a comparative use of the Thomistic theory of pure forms.” Collins, The Thomistic Philosophy of the Angels, xii-xiii.