Article 8 — Whether all angels differ in species from one another

Eighth, it is asked whether all angels differ in species from one another. (Parallel texts: On Being and Essence, ch. 5; ST I.50.4; In II Sent., d. 3, q. 1, aa. 4–5; SCG II.93, 95.)

Obj. 1: And it would seem that they do not. Augustine says in his Handbook on Faith, Hope, and Charity, the rational creaturehood which was in men, since by reason of sins and penalties . . . it had wholly perished deserved in part to be renewed. (Augustine, Enchiridion on Faith, Hope, and Charity, bk. 1, ch. 29 (PL 40:246); ch. 9, para. 29 (CCSL 46:65).) From this, it is argued as follows. If all angels were different from one another in their specific nature, then, since many angels fell irreparably, many natures would have irreparably perished. But divine providence does not allow any rational nature to perish entirely, as is clear from the passage quoted. Therefore, not all angels differ from one another in specific nature.

Obj. 2: Furthermore, the closer some things are to God, in whom there is no diversity, the less different they are. Now, according to the order of nature, angels are closer to God than men are. But beings which differ in number and in species are more different from one another than are those which differ in number and agree in species. Since, therefore, men do not differ in species, but only in number, it would seem that angels too do not differ in species.

Obj. 3: Furthermore, an agreement of things in their formal principle causes them to be the same in species, but a difference in their material principle makes them differ only in number. (Cf. SCG II.43, 93; ST I.66.6, ad 3; I.85.7, ad 3; Aristotle, Metaphysics 12.8, 1074a33–34.) Now in angels their very existence serves as the formal element with regard to the angel’s essence, as has been said above. (Above: a. 1, resp.) Since then all angels agree in existence but differ in essence, it would seem that angels differ, not in species, but only in number.

Obj. 4: Furthermore, every subsisting created substance is an individual, included under some nature common to a species in such a way that if the individual be a composite, the specific nature will be predicated of it according to its account as a composite, but if the individual is simple, the specific nature will be predicated of it in consideration of its simple accounts. Now, an angel is a subsisting created substance. Whether, then, it be composed of matter and form or whether it be simple, it must be included under some specific nature. But the fact that it can have many supposits does not detract from a specific nature; so too, the fact of having something like itself in the same species does not detract from an individual existing under such a nature. Therefore, it would seem to be possible that there are many angels belonging to one species. But in the case of eternal beings, there is no difference between “actual” and “possible,” as is said in Physics 3. (Aristotle, Physics 3.4, 203b30; cf. Aquinas, Commentary on Aristotle’s Physics, bk. 3, lect. 7, n. 341.) Therefore, among the angels there are many individuals of a single species.

Obj. 5: Furthermore, among the angels there is perfect love; accordingly, nothing which pertains to the perfection of love must be taken away from them. But the fact that there are many belonging to one species pertains to the perfection of love, because all living beings of one species naturally love one another, according to Ecclesiasticus: every creature loves its like (Sir 13:15). Therefore, in the case of angels, there are many belonging to one species.

Obj. 6: Furthermore, since a species alone has a definition, according to Boethius, (Boethius, On Division (PL 64:885D–86A); Commentary on Porphyry’s Isagoge, bk. 1, ch. 6 (PL 64:79D; CSEL 48:151–52).) all things which agree in their definition would seem to agree in their species. But all angels agree in that definition which Damascene lays down: an angel is an intellectual substance, always mobile, free in its will, incorporeal, serving God, receiving immortality in consequence of grace, not by nature. (John Damascene, On the Orthodox Faith, bk. 2, ch. 3 (PG 94:866). The reference to book 3 seems erroneous.) Therefore, all angels belong to one species.

Obj. 7: Furthermore, according to the order of nature, angels are closer to God than men are. But in God there are three persons of a nature one in number. Since then there are, among men, many persons of a nature one in species, it would seem that, for all the greater reason, among the angels there are many persons agreeing in a nature one in species.

Obj. 8: Furthermore, Gregory says (Gregory the Great, Homily on the Gospels, bk. 2, homily 34, para. 14 (PL 76:1255).) that in that heavenly country where there is a fullness of good, although certain attributes have been bestowed in an outstanding degree, yet none of these is possessed in an individual way; for all attributes are in all, not indeed equally, since some angels possess them in a more sublime degree than others, and yet all have them. There is, therefore, no difference in angels except one of “more and less.” But “more and less” do not constitute a specific difference. Therefore, angels do not differ in species.

Obj. 9: Furthermore, things which agree in what is most noble agree in species, because that which puts something in a species is more noble than that which puts a thing in a genus; for a specific difference is something formal in relation to a genus. But all angels agree in the most noble thing that is in them, namely, in intellectual nature. Therefore, all angels agree in species. (Cf. ST I.50.4, obj. 1.)

Obj. 10: Furthermore, if a given genus is divided by two differences, one of which is more imperfect than the other, the more imperfect difference is more capable of multiplication than is the more perfect; thus, for instance, “irrational” is multiplied in more species than is “rational.” Now, spiritual substance is divided by “capable of union” and “not capable of union”; but “capable of union with a body” is something more imperfect, in the case of spiritual substances. Since, then, a spiritual substance capable of union with a body, namely, the human soul, is not divided into many species, for all the greater reason a spiritual substance which is not capable of union, namely, an angel, is not multiplied in many species.

Obj. 11: Furthermore, Pope Boniface says that ministerial functions in the church militant are modelled after the heavenly host, wherein angels differ in orders and in power. (Pope Boniface, Epistle 2 (PL 65:43–44).) But in the church militant, a difference in orders and in power does not make men differ in species. Therefore, neither in the heavenly host of angels do angels differ in species, even those who are of different orders or hierarchies.

Obj. 12: Furthermore, just as the lower elements are adorned with plants and animals, and the sidereal heaven with stars, sun, and moon, so too the empyrean heaven is adorned with angels. (Cf. ST I.66.3, resp.) But among plants and animals many of the same species are found; likewise also, it would seem that all the stars belong to the same species, because they share in one most noble form, which is light. Therefore, it would seem by a parallel argument that either all angels or some angels agree in one species.

Obj. 13: Furthermore, if many angels are not asserted to agree in one species, this is only because there is no matter in them. But the removal of matter not only takes away plurality of individuals, but also their unity. For an individual is not put into a species except through matter, because matter is the principle of individuation. (See above: a. 5, obj. 8.) If, therefore, it must be asserted that angels are individuals in some sense, by a parallel argument it can also be asserted that there are many in one species.

Obj. 14: Furthermore, in those things which are separated from matter, the being which understands and that which is understood are the same, (Aristotle, On the Soul, 3.4, 430a3–4.) according to the Philosopher. If, then, angels were without matter, the angel which understands and the angel which is understood would be the same. But every angel understands every other angel. Therefore, it would follow that there is but one angel, which is false. One must not, therefore, assert that angels are without matter, and so neither must it be asserted that all the angels differ in species.

Obj. 15: Furthermore, number is a species of quantity, which is not apart from matter. If, then, there were no matter in the angels, there would be no number in them, which is false. Therefore, we reach the same conclusion as before.

Obj. 16: Furthermore, in those things which are without matter there is no multiplication except on a basis of cause and effect, as Rabbi Moses says. (Moses Maimonides, The Guide for the Perplexed, bk. 1, ch. 73; bk. 2, ch. 1, prop. 16; cf. Aquinas, Disputed Questions on the Soul, q. 3, obj. 6.) If, then, angels are without matter, either there is no manyness among them, or one is the cause of another; and both these alternatives are false. Therefore, we reach the same conclusion as before.

Obj. 17: Furthermore, creatures have been created by God in order that the divine goodness may be represented in them. But in a single species of “angel” the divine goodness is more perfectly represented than in the single species of “man.” Therefore, one should not posit many species of angels.

Obj. 18: Furthermore, different species which are divided as a result of being opposites differ by a specific difference. Now, it is impossible to indicate a number of opposite specific differences as great as the multitude of the angels is asserted to be. Therefore, not all angels differ in species.

On the contrary (1), if some angels agree in species, this would seem to be particularly the case with those who are of one order. But those who are of one order do not agree in species, since there are in the same order, the first, the intermediate, and the last, (Pseudo-Dionysius, The Celestial Hierarchy, ch. 10, para. 2 (PG 3:274B); ch. 4, para. 3 (PG 3:182A).) as Dionysius says in the tenth chapter of Celestial Hierarchy. A species, however, is not predicated of its own individuals in an order of sequence, as is said in Metaphysics 3. (Aristotle, Metaphysics 3.3, 999a6; 999a12–13.) There are not, therefore, many angels of one species. (Cf. ST I.50.4, s.c.)

Furthermore (2), only those things which are corruptible would seem to be multiplied in number in one species, in order that the specific nature, which cannot be preserved in one, may be preserved in many. But the angels are incorruptible. Therefore, there are not many angels of one species. (Cf. Aquinas, In II Sent., d. 3, q. 1, a. 4, s.c. 1; SCG II.93.)

Furthermore (3), the multiplication of individuals in one species takes place through a division of matter. But the angels are immaterial, because, as Augustine says in Confessions 12, (Augustine, Confessions, bk. 12, ch. 7, para. 7 (PL 32:828–29; CSEL 33:314; CCSL 27:220).) matter is next to nothing, whereas the angels are next to God. Therefore, in angels there is no multiplication of individuals in the same species. (Cf. SCG II.93.)

I answer that some have expressed themselves in different ways concerning this question. (Cf. Aquinas, In II Sent., d. 3, q. 1, a. 4, s.c. 1; ST I.50.4, resp.) For some have said that all spiritual substances belong to one species, (Cf. Origen, On First Principles, bk. 1, ch. 8, para. 2 (PG 11:176C–77A); bk. 2, ch. 9 (PG 11:229A); cf. Aquinas, SCG II.95.) but others, that all the angels of one hierarchy, or again, of one order, do. (Cf. Bonaventure, Commentary on the Sentences, bk. 2, d. 3, P. 1, a. 2, q. 1, concl.; d. 9, a. 1, q. 1, concl.) But others have said that all the angels differ from one another in species, (Cf. Pseudo-Dionysius, The Celestial Hierarchy, ch. 10, paras. 1–3 (PG 3:271–74); Alexander of Hales (ca. 1185–1245 AD), Summa universis theologiae (Summa fratris Alexandri), bk. 2–1, inq. 2, tract. 2, q. 1, ch. 6, a. 1 (113), sol.: dicendum quod angeli different inter se specie.) and this seems to me also to be true, for three reasons.

The first reason is derived from the makeup of their substance. For it is necessary to say, either that they are simple forms subsisting apart from matter, as was held above, (Above: a. 1, resp.) or that they are forms that are composed of matter and form. Now, if an angel is a simple form set apart from matter, it is impossible even to conceive several angels of one species; because any form whatever, however material and low, if it be set down as abstract either in actual being or in the intellect, remains but one form in one species. For, let “whiteness” be understood as something subsisting apart from every subject, and it will not be possible to posit many whitenesses, since we see that “this whiteness” does not differ from “that whiteness” save through the fact that it is in this or in that subject. In similar fashion, if there were an abstract “human nature,” there would be but one only. But if an angel is a substance that is composed of matter and form, it is necessary to say that the matters of different angels are somehow distinct. Now, the distinction of matter from matter is found to be one of only two kinds: (Cf. Aquinas, In I Sent., d. 2, q. 1, a. 1, ad 3; SCG I.65, 71; II.16, 30, 43.) one, according to the proper account of matter, and this is according to its relationship to different acts; for, since matter according to its proper account is in potency, whereas potency is spoken of in relation to act, (Cf. Aquinas, SCG I.20, 43; ST I.54.3, resp.; I.66.2, ad 4.) a distinction among potencies and matters is made from the standpoint of the order of acts.

And in this way, the matter of lower bodies, which is a potency to actual being, differs from the matter of the heavenly bodies, which is a potency to place. The second distinction of matter, however, is based on quantitative division, inasmuch as matter which exists under these particular dimensions is distinguished from that which is under other dimensions. And the first distinction of matter causes a generic diversity because, according to the Philosopher in Metaphysics 5, (Aristotle, Metaphysics 5.28, 1024b9–12; 10.3, 1054b28.) different things are different in genus on a basis of matter. The second distinction of matter, however, causes a diversity of individuals within the same species. Now, this second distinction of matter cannot exist among different angels, since angels are incorporeal and entirely without quantitative dimensions. The only remaining alternative, therefore, is that, if there be many angels that are composed of matter and form, there is a distinction of matters among them according to the first mode, and thus it follows that they differ not only in species but also in genus. (Cf. Aquinas, In II Sent., d. 3, q. 1, a. 4, resp.; ST I.50.4, resp.)

The second reason is derived from the order of the universe. For it is obvious that the good of the universe is of two kinds: something that is separate, namely, God, who is, as it were, the leader in an army; and a certain something in things themselves, and this is the order of the parts of the universe, just as the order of the parts of the army is the good of the army. (Cf. ST I.103, ad 3; Aristotle, Metaphysics 12.10, 1075a11–15.) Hence, the Apostle says there is no authority except from God, and those that exist have been instituted by God (Rom 13:1).

Now, the higher parts of the universe must have a greater share in the good of the universe, which is order. But those things in which there is order of themselves have a more perfect share in order than do those in which there is order only accidentally.

Now, it is obvious that, among all the individuals of one species, there is no order except accidentally. For they agree in the nature of the species and differ according to individuating principles and different accidents, which are related in an accidental way to the nature of the species. But things which differ in species have order of themselves and on a basis of their essential principles. For among the species of things, one is found to be greater than another, as is also the case in the species of numbers, as is said in Metaphysics 8. (Aristotle, Metaphysics 8.3, 1043b36–1044a2.) However, in the case of those lower things which are subject to generation and corruption, which make up the lowest part of the universe and have a lesser share in order, not all different things are found to have order of themselves, but certain ones have order only accidentally as, for example, the individuals of one species. But in the higher part of the universe, namely, among the heavenly bodies, order is not found accidentally but only essentially, since all heavenly bodies differ from one another in species, and there are not among them several individuals of one species, but one sun only, and one moon, and so of the others.

Much more so, therefore, in the highest part of the universe there are not to be found any beings that are ordered accidentally and not essentially. And so, the only remaining alternative is that all angels differ from one another in species, according to a greater and a lesser perfection of simple forms, as a result of a greater or a lesser nearness to God, who is pure act and of infinite perfection.

But the third reason is derived from the perfection of the angelic nature. For each individual thing is said to be perfect when it lacks none of those things which pertain to it. (Cf. Aristotle, Physics 3.6, 207a8–10.) And in fact, the degree of this perfection can be calculated from the extremes of things. For to God, who is at the apex of perfection, none of the things which belong to the account of actual being as a whole is lacking; for he has beforehand in himself absolutely and in the highest degree all the perfections of things, as Dionysius says. (Pseudo-Dionysius, On the Divine Names, ch. 5, para. 4 (PG 3:818D).)

But an individual in the lowest part of the world which contains beings that are subject to generation and corruption is found to be perfect from the fact that it has whatever pertains to itself, according to its own individual account, but not whatever pertains to its own specific nature, since its own specific nature is also found in other individual beings. And this quite obviously pertains to imperfection, not only in the case of animals that are subject to generation, among which one animal needs another of its own species for common life, but also in the case of all animals that are generated in any way whatever from semen, in which the male needs the female of its own species in order to generate; and, further, in the case of all beings that are subject to generation and corruption, wherein a group of individuals of one species is necessary in order that the specific nature, which cannot be perpetually conserved in one individual being because of its corruptibility, may be conserved in many.

But in the higher part of the universe, a higher degree of perfection is found, wherein one individual being, such as the sun, is so perfect that it lacks none of the things that pertain to its own species, and hence also the whole matter of the species is contained in one individual being. The same is true of the other heavenly bodies. Much more so, therefore, is this perfection found in the highest part of created things which is nearest to God, namely, among the angels; for that one individual lacks none of the things which pertain to a whole species, and thus there are not several individuals in one species. But God, who is at the summit of perfection, does not agree with any other being, not only in species but not even in genus, nor in any other univocal predicate. (Cf. Aquinas, SCG II.93.)

Reply Obj. 1: Augustine is there speaking of angelic and human nature, (Augustine, Enchiridion on Faith, Hope, and Charity, bk. 1, ch. 29 (PL 40:246); ch. 9, para. 29 (CCSL 46:65).) not according as they are considered in their natural actual being, but according as they are ordered toward beatitude. For in this sense some in the angelic and in the human nature have perished. As for the order of beatitude, human nature is contrasted with the whole angelic nature, because the whole angelic nature is naturally such as has been produced to attain to beatitude or to fall short of it in one single way, irreparably, namely, right at the first choice, but human nature, in the course of time. Consequently, Augustine is speaking there of all angels as of one nature, by reason of the single mode of their relation to beatitude, although they are different in the species of that nature.

Reply Obj. 2: Whenever one inquires into a difference or similarity of species, things are being studied from the standpoint of their natures. On this basis, one must not speak of all angels as of one nature that is closest to God, but only the first angel was, from this point of view, the nature closest to God. And in this nature, there is the least possible diversity, because there is neither diversity of species nor of number.

Reply Obj. 3: Actual being itself is related as an act, both to composite natures and to simple natures. Therefore, just as in the case of composite natures the species is not derived from their actual being itself, but from their form, because a species is predicated as something essential, whereas actual being seems to pertain to the question of a thing’s existence; hence, neither in the case of angelic substances is the species obtained on a basis of actual being itself, but on a basis of simple subsistent forms, whose difference depends on the order of perfection, as has been said. (Above: resp.)

Reply Obj. 4: Just as a form, which is in a subject or in matter, is individuated by the fact that it is in this particular thing, so a separated form is individuated by the fact that it is not naturally such as to exist in anything. (Cf. ST III.77.2, resp.; On the Unity of the Intellect against the Averroists, ch. 5.) For, just as actually being in this particular thing excludes the commonness of a universal, which is predicated of many individuals, so does not being able to exist in some subject.

Accordingly, just as “this particular whiteness” is not prevented from having many individuals under it in consequence of the fact that it is whiteness, which pertains to its specific account, but because it is in “this particular subject,” which pertains to its individual account, so too the nature of “this particular angel” is not prevented from existing in many in consequence of the fact that it is a nature in a given order of things, which pertains to its specific account, but because this nature has not a natural capacity for being received in a given subject, which pertains to the account of an individual.

Reply Obj. 5: Since affection follows knowledge, the more universal knowledge is, so much the more does the affection which follows it look toward the common good; and the more particular the knowledge is, so much the more does the affection which follows it look toward a private good. Hence, among us too, individual love arises as a consequence of sense knowledge, but the love of the common and absolute good arises as a consequence of intellectual knowledge. (Cf. Augustine, On the Literal Interpretation of Genesis, bk. 11, ch. 15, para. 19 (PL 34:436; CSEL 28.1:347).) Accordingly, because the angels, in proportion as they are higher, possess a more universal knowledge, as Dionysius says in the twelfth chapter of Celestial Hierarchy, (Pseudo-Dionysius, The Celestial Hierarchy, ch. 12, para. 2 (PG 3:291–94).) so does their love, as a consequence, look especially to the common good. Consequently, they love one another more if they differ in species, which pertains rather to the perfection of the universe, as has been shown, (Above: resp.) than if they were to agree in species, which would pertain to the private good of a single species.

Reply Obj. 6: Our soul, when it is united to the body, cannot understand separated substances in their essences, so as to know of them what they are. For their essences are above the genus of sensible natures and out of proportion to them, and from these our intellect gets its knowledge. Consequently, separated substances cannot be defined by us in the strict sense, but only through negation or through some activity of these same substances. Damascene defines an angel in this way, not by a definition belonging to the most specific species, but to a subordinate genus, which is a genus and a species; hence, a definition is possible.

Reply Obj. 7: The mode of distinction between the divine persons is unconnected with diversity of essence, and this a created nature does not allow; consequently, this fact cannot lead to a conclusion in the case of creatures.

Reply Obj. 8: “More and less” is taken in two senses: in one sense, with reference to a different manner of participating in one and the same form, just as a more white thing is said to be more bright than a less white thing, and in this sense “more and less” do not constitute a specific difference. In another sense, “more and less” is used with reference to a degree of different forms; thus, for instance, something white is said to be more bright than red or green. And in this sense, “more and less” do constitute a specific difference. In this way, angels differ in natural spiritual gifts on a basis of “more and less.”

Reply Obj. 9: What establishes something in a species is more noble than what establishes something in a genus, in the sense in which something determinate is more noble than something indeterminate. For the determinate is related to the indeterminate as act is related to potency; this is not, however, in the sense that what establishes something in a species always belongs to a more noble nature, as is evident in the species of irrational animals. For species of this sort are not constituted by the addition of another more noble nature over and above the sensitive nature, which is the noblest nature in them, but through their being determined to different degrees within that nature. Something similar must be said of the intellectual nature, which is the common characteristic in angels.

Reply Obj. 10: It does not seem to be universally true that a more imperfect difference of genus is multiplied into several species. For “body” is divided into “animate body” and “inanimate body”; yet there would seem to be more species of animate bodies than of inanimate, particularly if the heavenly bodies are animate, and if all the stars differ from one another in species. But in both plants and animals there is a very great diversity of species. Still, in order that the truth of this matter may be investigated, it must be borne in mind that Dionysius would seem to present a view that is contrary to the Platonists. For the Platonists say that the nearer substances are to the primary one, the less numerous they are. (Cf. Book of Causes, prop. 4.) But Dionysius says in the fourteenth chapter of Celestial Hierarchy (Pseudo-Dionysius, The Celestial Hierarchy, ch. 14 (PG 3:322).) that angels transcend all material manyness. Now, that both these statements are true, anyone can perceive from corporeal objects, among which the higher a given body is found to be, the less matter it has, but the greater is its quantitative extent.

Hence, since number is, in a way, the cause of continuous quantity, seeing that unity constitutes a point and a point constitutes a line, speaking after the fashion of the Platonists, (Aristotle, On the Heavens 3.1, 299a6–11; On the Soul 1.4, 409a3–5.) so also is it the case in the whole universe that the higher some things are among beings, the more do they have of formal manyness, which is reckoned according to a distinction of species, and in this sense the saying of Dionysius is saved; (Pseudo-Dionysius, The Celestial Hierarchy, ch. 14 (PG 3:322).) whereas they have less of material manyness, which is reckoned according to a distinction between individuals within the same species, and in this sense the saying of the Platonists is saved. Now, the fact that there is only one species of rational animal, although many species of irrational animals exist, arises from the fact that “rational animal” is constituted on this basis, that corporeal nature at its highest point touches the nature of spiritual substances at its lowest point. Now, the highest level of any nature, or even the lowest level, is one only. Although, it might be said that there are many species of rational animals, if one were to hold that the heavenly bodies are animate.

Reply Obj. 11: Men are included among corruptible creatures, which form the lowest part of the universe, wherein are found some beings that are related not only essentially, but also accidentally. Consequently, in the church militant, a difference in power and in orders does not make a difference of species; but it is otherwise in the case of the angels, who form the highest part of the universe, as has been said. (Above: ad 1.) Now, there is in men a likeness to angels, although not a perfect likeness, but one that is accidental, as has been said. (Above: ad 1.)

Reply Obj. 12: The ornaments of earth and water, because they are corruptible, need manyness within the same species, as has been said. (Above: resp.) Now, the heavenly bodies also are of different species, as has been said. (Above: resp.) For light is not their substantial form, since it is a directly sensible quality, and this cannot be said of any substantial form; furthermore, light does not have the same account in all things, as is clear from the fact that the radiations of different bodies have different effects.

Reply Obj. 13: Individuation, in the case of the angels, is not through matter but through the fact that they are self-subsistent forms, which do not have a natural capacity for existing in a subject or in matter, as has been said. (Above: resp.)

Reply Obj. 14: The early philosophers asserted that the knowing subject should be of the same nature as the thing known. (Cf. Aristotle, On the Soul 1.2, 404b16–18.) Hence, Empedocles said that we know the earth through earth and the water through water. (Aristotle, On the Soul 1.2, 404b11–15.)

But to rule this out, Aristotle asserted that the knowing power in us, according as it is in potency, is void of the nature of the things that can be known; thus, the pupil of the eye, for instance, is void of color. (Aristotle, On the Soul 3.4, 429a18–22; Aquinas, Commentary on Aristotle’s On the Soul, bk. 3, lect. 1, n. 680; In II Sent., d. 17, q. 2, a. 1, ad 4; SCG II.59.) But yet the sense in act is the thing sensed in act, (Aristotle, On the Soul 3.2, 426a15–16; cf. SCG I.51.) inasmuch as the sense is put in act through being informed by the sensible species.

By the same reasoning, the intellect in act is the thing understood in act, (Aristotle, On the Soul 3.4, 430a3–4; 430a19–20; Metaphysics 12.9, 1075a3–5; cf. Aquinas, Commentary on the Metaphysics, bk. 12, lect. 11, n. 2620.) inasmuch as it is informed by the intelligible species, for a stone does not exist in the soul, but the species of a stone, (Aristotle, On the Soul 3.8, 431b29.) as he himself says. Now, the reason why something is intelligible in act is that it is separated from matter; consequently, he says that in those things which are without matter, the understanding subject and the thing which is understood are the same. (Aristotle, On the Soul 3.4, 430a2.) Therefore, the understanding angel need not be the same in substance as the understood angel, if they are immaterial, but the understanding of the one must be informed by a likeness of the other.

Reply Obj. 15: The number which is caused by the division of a continuum is a species of quantity, and it exists only in material substances. But in immaterial substances, there is a manyness which derives from the transcendentals, inasmuch as “one” and “many” are divisions of being. This manyness is the result of a formal distinction.

Reply Obj. 16: A difference of cause and effect is asserted by some to multiply separated substances, (As by Rabbi Moses in the above objection 16.) inasmuch as they assert that different degrees arise among them, insofar as an effect is lower than its cause. Hence, if we assert different degrees among spiritual substances in consequence of the arrangement of the divine wisdom which is their cause, the account of the distinction will remain the same, even though one of these substances is not the cause of the other.

Reply Obj. 17: No created nature, since it is finite, represents the divine goodness as perfectly as a multitude of natures does, because what is contained in many natures in a multiple way is included in God as a unity; consequently, there ought to be many natures in the universe and also among the angelic substances.

Reply Obj. 18: The opposition of the differences that constitute the angelic species is understood on a basis of perfect and imperfect, or the exceeding and the exceeded, as is the case also in numbers; thus also is animate related to inanimate, and other things of the sort.