Thomas Aquinas: Soul and Intellect

Supplementary Translations:

Aquinas In 1 Sent. d. 8, q.5, a.2


© Richard C. Taylor, Marquette University, 30 September 2012

This translation was made for the graduate course Aquinas: Soul and Intellect

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Thomas Aquinas, In 2 Sent D. 3, Q. 1, A. 6

Whether the angel and the [human] soul differ in species

To the sixth we proceed as follows.

1. It seems that the angel and the soul do not differ in species. For whatever things agree in ultimate constitutive difference are the same in species, because it is what completes the notion (rationem) of the species. But the angel and the soul are of the same sort. Therefore they do not differ in species. The proof of the minor: The ultimate constitutive difference is taken from the fact that it is what is most noble in the thing, since it is related to the genus and precedent differences proportionally as form to matter. But the angel and the soul agree in regard to what is most noble in both, namely in the intellect. Therefore, they agree in the ultimate constitutive difference.

2. If you were to say that the ultimate constitutive difference of an angel is intellectual because it is taken from the intellect, while the ultimate difference of the soul is rational, as also Dionysius says (Ecc. hier. col. 374, t. I), it seems to make a distinction between the order of intellects and that of rational entities. To the contrary: Things which commonly agree in two things do not have a distinction between them (non distinguunt inter ipsa). But the intellect is placed not only in angels but also in the soul, as is clear in De anima 3, text 5: likewise also not only belongs to the soul but also to the angel. Hence, Gregory (in Homil. Ephiph, col. 1110, t. II) calls the angel a rational animal. And above the Master [Lombard] distinguished rational creation into the angel and the soul. Therefore, the angel and the soul do not differ at all as rational and intellectual.

3. If you were to say that it is distinguished as unitable (unibile) to body and as not unitable (non unibile) [to body], to the contrary: Whatever follows upon a thing having complete being does not distinguish it essentially from another thing, because all things of this sort which follow upon a thing in this way are of the genus of accidents. But the union to the body which is a certain relation which follows for a soul having complete being in itself not depending on the body, [for] otherwise it could not exist without the body (alias sine corpore esse non posset). Therefore that it is unitable to body does not distinguish soul from angel essentially or according to species.

4. Furthermore, the specific difference is not assigned to some thing except insofar as it is in the genus as species, because the difference is that by which the species flows from the genus. But the soul, insofar as it is the form of such a body, is not in the genus of substance as species but rather as principle. Therefore, since unitability does not belong to the soul except insofar as it is form, it seems that unitable being (esse unibile) cannot be what distinguishes the soul from the angel according to species.

5. Furthermore, things which are such that they have one end do not differ in species, since the end corresponds more properly to any given thing. But the end of the angel and of the rational soul is the same, namely eternal beatitude, as the Master [Lombard] says above. This can also be gathered from what is said at Matthew 23, 30: They will be as the angels of God in heaven.  Therefore the angel and the soul do not differ in species.

On the contrary, the soul differs more from the angel than one angel from another. But one angel differs from another in species. as was said. Therefore, all the more so [does] the soul [differ] from the angel.

Furthermore, the same perfectible corresponds to the same form or perfection. But the soul and the angel are certain forms, to the extent that we say commonly that all substances separate from matter are forms, of which material forms are images, as Boethius says in Book 1 of De Trinitate [c. II, col. 1250, t. II]. Therefore, since this perfectible which is the human body corresponds to the soul, but to the angel [there corresponds] either nothing or another species, as with the etherial body, according to what Augustine [book 3, De Gen ad lit., c. II, col 280, t. III] seems to say, or even the celestial body according to the opinion of Avicenna [lib. De intelligentiis] and certain other philosophers, then it seems that the soul and the angel are not of one species.


I respond that concerning this there are three opinions.

(1) For some say that the soul is not in the genus of substance as species but as principle, since it is the form. Hence, the soul is not properly said to differ from or to agree with some other substance [in species], but it is properly said that what is composed from another or with another substance agrees or differs in species according to soul (sed proprie dicitur, quod secundum animam compositum ab alia vel cum alia substantia convenit specie vel differt). But  this does not seem necessary because, as Avicenna says in his Metaphysics (book 2, c.1, & book 6, c. 5), to the extent that something is properly in the genus of substance it is required that it be a thing having a quiddity, to which there belongs absolute being (cui debeatur esse absolutum), so that it may be said to exist per se or be subsisting. For this reason it can happen in two ways that something pertaining to the genus of substance is not in the genus of substance as species: either because that thing does not have a quiddity other than its own being, and  on account of this God is not in the genus of substance as species, as Avicenna humself says, as indicated above (in Metaphysics book 6, ch, 5-7); or because that thing does not have absolute being so that it can be called a being in its own right (ens per se), and on account of this prime matter and material forms are not in the genus of substance as species, but only as principles. The rational soul, however, has absolute being not dependent on matter because it is other than its quiddity, as also is said about the angels. For this reason it remains that it is in the genus of substance as species and also as principle insofar as it is form of this body. And as a result that distinction comes about, because of forms some are material forms which are not species of substance, while some are forms and substances, as rational souls.

(2) The second opinion is that of those who say the soul and the angel to be of one species. This can in no way be the case if the composition of form and matter is denied of [both] the soul and the angel, as was said regarding the angels.

(3) And for this reason a third opinion is more common to which it seems one ought to assent, that the soul and the angel differ in species.

However, by what specific differences they are distinguished is assigned in diverse ways. For some  assign these to be distinguished by species through the fact that it is unitable to the body and not unitable [to the body]. But others [assign the specific differences] in virtue of rational being and intellectual [being]. With a third [difference is assigned] insofar as there is [the difference of] having possible intellect with respect to higher things only, which belongs to the angel which receives illumination from the higher, namely, from God or an angel.  According to this [the difference] is constituted in having possible intellect with respect to what is higher and [also with respect to] what is lower; this belongs to the human soul which is illuminated also by what is higher and [yet] receives cognition from phantasms. For a fourth [difference is assigned] insofar as there is [the difference of] having unchangeable veritability, which belongs to the angel, in virtue of the fact that it immutably adheres to good or bad in regard to the fact that it turns itself once through choice, or [insofar as there is the difference of] having mutable veritability which belongs to the human being who is able to change from good into bad, and the contrary. For a fifth [difference is assigned] according to interpretative power, because, according to Damascene [lib II, Orth. fidei, ch. III, col. 267, t. I] the angel interprets or speaks by certain nods and intellectual signs without expression of voice, as will be clear below; the human being, however, speaks with expressed voice. Nor is there any wonder that angels and souls are assigned to differ in diverse ways such as this because essential differences which are unknown and unnamed, according to the Philosopher [Metaph. VII, text. 35], are designated by different accidents which are caused by essential [differences], as the cause is designated through its effect, as hot and cold are assigned as the differences of fire and water. Hence, many differences can be assigned as specific [differences], according to many properties of things differing in species, from essential differing effects. Nevertheless, of these those are better assigned which are prior, as more proximate to essential differences.

Since, therefore, among simple substances, as was said regarding angels, there is a difference in species according to the grade of possibility in these, then on the basis of this the rational animal differs from the angel because it holds the last grade in spiritual substances, as prime matter [holds the last grade] in sensible things, as the Commentator says in De Anima 3, [comm. 5 & 6]. Hence, because it has more of possibility, its being is to this extent near to material things so that material body is able to participate that, while the soul is united to the body in one being. For this reason those differences unitable and not unitable follow between soul and angel from the diverse grade of possibility. Again from the same the other differences, rational and intellectual, follow, because from the fact that the angel has more of act than the soul and has less of potency, it participates intellectual nature as it were in full light, in virtue of which it is called intellectual. But the soul, because it holds the lowest grade in intellectual things, participates intellectual nature more defectively as if placed under a shadow. For this reason it is called rational because reason, as Isaac says [in the book On Definitions], arises in the shadow of intelligence. A third distinction follows from the first and second, for from the fact that the soul is form and act of the body, from its essence there proceed  certain powers affixed to organs, such as sense and the like, from which it receives intellectual cognition. [This is] on account of the fact that what rational is something that has cognition running from one thing to another and in this way it comes from sensibles to intelligibles. In virtue of this [soul] differs from angel which does not receive cognition from sensibles by working toward intelligibles.  However, a fourth distinction follows from the second because it is said that in virtue of the fact that the angel has a god-like intellect (intellectum deiformem), it turns toward anything without motion. In this the angel is said to differ from the soul which is does not have a god-like intellect but rather has cognition through the inquisition of reason. A fifth [difference]  also follows from the first because on account of the fact that the soul is united to the body it can form a bodily voice, while the angel cannot.

Hence it is evident that the first of those distinctions is the better because it is taken according to the being of the soul which is first. The second and the third are taken with the presence of the cognitive or intellective power, as the second, or with the presence of the intellective and sensitive at once, as the third. However, the fourth is taken with the presence of the appetitive power, because choice pertains to appetite, as the Philosopher says in the Ethics [book 6, ch. 2], through which the soul mutably changes. Hence, since the appetitive is posterior to the cognitive, this is less dominant than those that precede. The fifth is taken with the presence of the motive power, for the formation of the voice is through the bodily motion of parts. However, the motive [power] is posterior to the cognitive and appetitive, hence it is less dominant among them.

Responses to objections

1. To the first, therefore, it should be said that the difference is not more noble than the genus as one nature is more noble than another, or as one form is more noble than another, because the difference indicates no form which is not contained implicitly in the nature of the genus, as Avicenna says [in Metaphysics 5, last chapter]. For the genus does not signify a part of the essence of the thing but rather the whole. But it is called more noble in genus, as the determinate [is more noble] than the indeterminate. In this way to have intellect is more noble than to have intellect simply [simpliciter]; to have sense in this way is more noble than to have sense simply [simpliciter] (Sed dicitur genere nobilior, sicut determinatum indeterminato; et per hunc modum habere intellectum sic, est nobilius quam habere inteIlectum simpliciter; et habere sensum sic, quam habere sensum simpliciter.) For this reason soul and angel do not come together in what is more noble in them in that way. Hence, it is not necessary that they come together in the ultimate specific difference and so would be same in species.

2. To the second it should be said that in the human being there is intellect. Nevertheless, it is not placed in the order of intellects on account of that, because that intellectual substance  is said to be that whose whole cognition is according to intellect, because all the things which it knows are offered to it immediately and without inquiry. However, it is not so concerning the cognition of the soul because it comes to knowledge of a thing through inquiry and discourse of reason. For this reason it is called rational because its cognition according to the end term and according to the beginning is intellectual. [This is so] according to beginning because it knows the first principle immediately without inquiry; hence the intellect is said to be a disposition (habitus) of indemonstrable principles, but determinate because the inquisition of reason is terminated at the knowledge (intellectum) of the thing. For this reason it does not have intellect as proper nature but through a certain participation. However, reason is said both of God and of angels. but nevertheless it is taken in another way insofar as every cognition can be called  an immaterial reason (immaterialis ratio), to the extent that  reason is divided against sense, and not against intellect.

3. To the third it should be said that unitability is not a proper essential difference, but is a certain designation of an essential difference through the effect, as was said.

4. And in virtue of this the response to the fourth is evident, because that which belongs to soul insofar as it is form is an effect of the essential difference.

5. To the fifth it should be said that those things which differ in species differ according to a proximate end which is permanence or operation of a thing, as is said in On the heavens, II. Nevertheless, they can come together in the ultimate end and beatitude is an end of this sort.