Summa Th. I-II EN Qu.49 a.3
Objection: 1. It would seem that habit does not imply order to an act. For everything acts according as it is in act. But the Philosopher says (De Anima iii, text 8), that "when one is become knowing by habit, one is still in a state of potentiality, but otherwise than before learning." Therefore habit does not imply the relation of a principle to an act.
2. Further, that which is put in the definition of a thing, belongs to it essentially. But to be a principle of action, is put in the definition of power, as we read in Metaph. v, text. 17. Therefore to be the principle of an act belongs to power essentially. Now that which is essential is first in every genus. If therefore, habit also is a principle of act, it follows that it is posterior to power. And so habit and disposition will not be the first species of quality.
3. Further, health is sometimes a habit, and so are leanness and beauty. But these do not indicate relation to an act. Therefore it is not essential to habit to be a principle of act.
On the contrary Augustine says (De Bono Conjug. xxi) that "habit is that whereby something is done when necessary." And the Commentator says (De Anima iii) that "habit is that whereby we act when we will."
I answer that To have relation to an act may belong to habit, both in regard to the nature of habit, and in regard to the subject in which the habit is. In regard to the nature of habit, it belongs to every habit to have relation to an act. For it is essential to habit to imply some relation to a thing's nature, in so far as it is suitable or unsuitable thereto. But a thing's nature, which is the end of generation, is further ordained to another end, which is either an operation, or the product of an operation, to which one attains by means of operation. Wherefore habit implies relation not only to the very nature of a thing, but also, consequently, to operation, inasmuch as this is the end of nature, or conducive to the end. Whence also it is stated (Metaph. v, text. 25) in the definition of habit, that it is a disposition whereby that which is disposed, is well or ill disposed either in regard to itself, that is to its nature, or in regard to something else, that is to the end.But there are some habits, which even on the part of the subject in which they are, imply primarily and principally relation to an act. For, as we have said, habit primarily and of itself implies a relation to the thing's nature. If therefore the nature of a thing, in which the habit is, consists in this very relation to an act, it follows that the habit principally implies relation to an act. Now it is clear that the nature and the notion of power is that it should be a principle of act. Wherefore every habit is subjected in a power, implies principally relation to an act.
Reply to Objection: 1. Habit is an act, in so far as it is a quality: and in this respect it can be a principle of operation. It is, however, in a state of potentiality in respect to operation. Wherefore habit is called first act, and operation, second act; as it is explained in De Anima ii, text. 5.
2. It is not the essence of habit to be related to power, but to be related to nature. And as nature precedes action, to which power is related, therefore habit is put before power as a species of quality.
3. Health is said to be a habit, or a habitual disposition, in relation to nature, as stated above. But in so far as nature is a principle of act, it consequently implies a relation to act. Wherefore the Philosopher says (De Hist. Animal. x, 1), that man, or one of his members, is called healthy, "when he can perform the operation of a healthy man." And the same applies to other habits.
Objection: 1. It would seem that habits are not necessary. For by habits we are well or ill disposed in respect of something, as stated above. But a thing is well or ill disposed by its form: for in respect of its form a thing is good, even as it is a being. Therefore there is no necessity for habits.
2. Further, habit implies relation to an act. But power implies sufficiently a principle of act: for even the natural powers, without any habits, are principles of acts. Therefore there was no necessity for habits.
3. Further, as power is related to good and evil, so also is habit: and as power does not always act, so neither does habit. Given, therefore, the powers, habits become superfluous.
On the contrary Habits are perfections (Phys. vii, text. 17). But perfection is of the greatest necessity to a thing: since it is in the nature of an end. Therefore it is necessary that there should be habits.
I answer that As we have said above (Articles ,3), habit implies a disposition in relation to a thing's nature, and to its operation or end, by reason of which disposition a thing is well or ill disposed thereto. Now for a thing to need to be disposed to something else, three conditions are necessary. The first condition is that which is disposed should be distinct from that to which it is disposed; and so, that it should be related to it as potentiality is to act. Whence, if there is a being whose nature is not composed of potentiality and act, and whose substance is its own operation, which itself is for itself, there we can find no room for habit and disposition, as is clearly the case in God.The second condition is, that that which is in a state of potentiality in regard to something else, be capable of determination in several ways and to various things. Whence if something be in a state of potentiality in regard to something else, but in regard to that only, there we find no room for disposition and habit: for such a subject from its own nature has the due relation to such an act. Wherefore if a heavenly body be composed of matter and form, since that matter is not in a state of potentiality to another form, as we said in the I 56,2, there is no need for disposition or habit in respect of the form, or even in respect of operation, since the nature of the heavenly body is not in a state of potentiality to more than one fixed movement.The third condition is that in disposing the subject to one of those things to which it is in potentiality, several things should occur, capable of being adjusted in various ways: so as to dispose the subject well or ill to its form or to its operation. Wherefore the simple qualities of the elements which suit the natures of the elements in one single fixed way, are not called dispositions or habits, but "simple qualities": but we call dispositions or habits, such things as health, beauty, and so forth, which imply the adjustment of several things which may vary in their relative adjustability. For this reason the Philosopher says (Metaph. v, text. 24,25) that "habit is a disposition": and disposition is "the order of that which has parts either as to place, or as to potentiality, or as to species," as we have said above (Article , ad 3). Wherefore, since there are many things for whose natures and operations several things must concur which may vary in their relative adjustability, it follows that habit is necessary.
Reply to Objection: 1. By the form the nature of a thing is perfected: yet the subject needs to be disposed in regard to the form by some disposition. But the form itself is further ordained to operation, which is either the end, or the means to the end. And if the form is limited to one fixed operation, no further disposition, besides the form itself, is needed for the operation. But if the form be such that it can operate in diverse ways, as the soul; it needs to be disposed to its operations by means of habits.
2. Power sometimes has a relation to many things: and then it needs to be determined by something else. But if a power has not a relation to many things, it does not need a habit to determine it, as we have said. For this reason the natural forces do not perform their operations by means of habits: because they are of themselves determined to one mode of operation.
3.The same habit has not a relation to good and evil, as will be made clear further on (Question , Article ): whereas the same power has a relation to good and evil. And, therefore, habits are necessary that the powers be determined to good.
We consider next the subject of habits: and under this head there are six points of inquiry:
(1) Whether there is a habit in the body?
(2) Whether the soul is a subject of habit, in respect of its essence or in respect of its power?
(3) Whether in the powers of the sensitive part there can be a habit?
(4) Whether there is a habit in the intellect?
(5) Whether there is a habit in the will?
(6) Whether there is a habit in separate substances?
Objection: 1. It would seem that there is not a habit in the body. For, as the Commentator says (De Anima iii), "a habit is that whereby we act when we will." But bodily actions are not subject to the will, since they are natural. Therefore there can be no habit in the body.
2. Further, all bodily dispositions are easy to change. But habit is a quality, difficult to change. Therefore no bodily disposition can be a habit.
3. Further, all bodily dispositions are subject to change. But change can only be in the third species of quality, which is divided against habit. Therefore there is no habit in the body.
On the contrary The Philosopher says in the Book of Predicaments (De Categor. vi) that health of the body and incurable disease are called habits.
I answer that As we have said above (Question , Articles  seqq.), habit is a disposition of a subject which is in a state of potentiality either to form or to operation. Therefore in so far as habit implies disposition to operation, no habit is principally in the body as its subject. For every operation of the body proceeds either from a natural quality of the body or from the soul moving the body. Consequently, as to those operations which proceed from its nature, the body is not disposed by a habit: because the natural forces are determined to one mode of operation; and we have already said (Question , Article ) that it is when the subject is in potentiality to many things that a habitual disposition is required. As to the operations which proceed from the soul through the body, they belong principally to the soul, and secondarily to the body. Now habits are in proportion to their operations: whence "by like acts like habits are formed" (Ethic. ii, 1,2). And therefore the dispositions to such operations are principally in the soul. But they can be secondarily in the body: to wit, in so far as the body is disposed and enabled with promptitude to help in the operations of the soul.If, however, we speak of the disposition of the subject to form, thus a habitual disposition can be in the body, which is related to the soul as a subject is to its form. And in this way health and beauty and such like are called habitual dispositions. Yet they have not the nature of habit perfectly: because their causes, of their very nature, are easily changeable.On the other hand, as Simplicius reports in his Commentary on the Predicaments, Alexander denied absolutely that habits or dispositions of the first species are in the body: and held that the first species of quality belonged to the soul alone. And he held that Aristotle mentions health and sickness in the Book on the Predicaments not as though they belonged to the first species of quality, but by way of example: so that he would mean that just as health and sickness may be easy or difficult to change, so also are all the qualities of the first species, which are called habits and dispositions. But this is clearly contrary to the intention of Aristotle: both because he speaks in the same way of health and sickness as examples, as of virtue and science; and because in Phys. vii, text. 17, he expressly mentions beauty and health among habits.
Reply to Objection: 1. This objection runs in the sense of habit as a disposition to operation, and of those actions of the body which are from nature: but not in the sense of those actions which proceed from the soul, and the principle of which is the will.
2. Bodily dispositions are not simply difficult to change on account of the changeableness of their bodily causes. But they may be difficult to change by comparison to such a subject, because, to wit, as long as such a subject endures, they cannot be removed; or because they are difficult to change, by comparison to other dispositions. But qualities of the soul are simply difficult to change, on account of the unchangeableness of the subject. And therefore he does not say that health which is difficult to change is a habit simply: but that it is "as a habit," as we read in the Greek [*(isos hexin) (Categor. viii)]. On the other hand, the qualities of the soul are called habits simply.
3. Bodily dispositions which are in the first species of quality, as some maintained, differ from qualities of the third species, in this, that the qualities of the third species consist in some "becoming" and movement, as it were, wherefore they are called passions or passible qualities. But when they have attained to perfection (specific perfection, so to speak), they have then passed into the first species of quality. But Simplicius in his Commentary disapproves of this; for in this way heating would be in the third species, and heat in the first species of quality; whereas Aristotle puts heat in the third.Wherefore Porphyrius, as Simplicius reports (Commentary), says that passion or passion-like quality, disposition and habit, differ in bodies by way of intensity and remissness. For when a thing receives heat in this only that it is being heated, and not so as to be able to give heat, then we have passion, if it is transitory; or passion-like quality if it is permanent. But when it has been brought to the point that it is able to heat something else, then it is a disposition; and if it goes so far as to be firmly fixed and to become difficult to change, then it will be a habit: so that disposition would be a certain intensity of passion or passion-like quality, and habit an intensity or disposition. But Simplicius disapproves of this, for such intensity and remissness do not imply diversity on the part of the form itself, but on the part of the diverse participation thereof by the subject; so that there would be no diversity among the species of quality. And therefore we must say otherwise that, as was explained above (Question , Article , ad 1), the adjustment of the passion-like qualities themselves, according to their suitability to nature, implies the notion of disposition: and so, when a change takes place in these same passion-like qualities, which are heat and cold, moisture and dryness, there results a change as to sickness and health. But change does not occur in regard to like habits and dispositions, primarily and of themselves.
Objection: 1. It would seem that habit is in the soul in respect of its essence rather than in respect of its powers. For we speak of dispositions and habits in relation to nature, as stated above (Question , Article ). But nature regards the essence of the soul rather than the powers; because it is in respect of its essence that the soul is the nature of such a body and the form thereof. Therefore habits are in the soul in respect of its essence and not in respect of its powers.
2. Further, accident is not the subject of accident. Now habit is an accident. But the powers of the soul are in the genus of accident, as we have said in the I 77,1, ad 5. Therefore habit is not in the soul in respect of its powers.
3. Further, the subject is prior to that which is in the subject. But since habit belongs to the first species of quality, it is prior to power, which belongs to the second species. Therefore habit is not in a power of the soul as its subject.
On the contrary The Philosopher (Ethic. i, 13) puts various habits in the various powers of the soul.
I answer that As we have said above (Question , Articles ,3), habit implies a certain disposition in relation to nature or to operation. If therefore we take habit as having a relation to nature, it cannot be in the soul---that is, if we speak of human nature: for the soul itself is the form completing the human nature; so that, regarded in this way, habit or disposition is rather to be found in the body by reason of its relation to the soul, than in the soul by reason of its relation to the body. But if we speak of a higher nature, of which man may become a partaker, according to 2P 1, "that we may be partakers of the Divine Nature": thus nothing hinders some habit, namely, grace, from being in the soul in respect of its essence, as we shall state later on (Question , Article ).On the other hand, if we take habit in its relation to operation, it is chiefly thus that habits are found in the soul: in so far as the soul is not determined to one operation, but is indifferent to many, which is a condition for a habit, as we have said above (Question , Article ). And since the soul is the principle of operation through its powers, therefore, regarded in this sense, habits are in the soul in respect of its powers.
Reply to Objection: 1. The essence of the soul belongs to human nature, not as a subject requiring to be disposed to something further, but as a form and nature to which someone is disposed.
2. Accident is not of itself the subject of accident. But since among accidents themselves there is a certain order, the subject, according as it is under one accident, is conceived as the subject of a further accident. In this way we say that one accident is the subject of another; as superficies is the subject of color, in which sense power is the subject of habit.
3. Habit takes precedence of power, according as it implies a disposition to nature: whereas power always implies a relation to operation, which is posterior, since nature is the principle of operation. But the habit whose subject is a power, does not imply relation to nature, but to operation. Wherefore it is posterior to power. Or, we may say that habit takes precedence of power, as the complete takes precedence of the incomplete, and as act takes precedence of potentiality. For act is naturally prior to potentiality, though potentiality is prior in order of generation and time, as stated in Metaph. vii, text. 17; ix, text. 13.
Objection: 1. It would seem that there cannot be any habits in the powers of the sensitive part. For as the nutritive power is an irrational part, so is the sensitive power. But there can be no habits in the powers of the nutritive part. Therefore we ought not to put any habit in the powers of the sensitive part.
2. Further, the sensitive parts are common to us and the brutes. But there are not any habits in brutes: for in them there is no will, which is put in the definition of habit, as we have said above (Question , Article ). Therefore there are no habits in the sensitive powers.
3. Further, the habits of the soul are sciences and virtues: and just as science is related to the apprehensive power, so it virtue related to the appetitive power. But in the sensitive powers there are no sciences: since science is of universals, which the sensitive powers cannot apprehend. Therefore, neither can there be habits of virtue in the sensitive part.
On the contrary The Philosopher says (Ethic. iii, 10) that "some virtues," namely, temperance and fortitude, "belong to the irrational part."
I answer that The sensitive powers can be considered in two ways: first, according as they act from natural instinct: secondly, according as they act at the command of reason. According as they act from natural instinct, they are ordained to one thing, even as nature is; but according as they act at the command of reason, they can be ordained to various things. And thus there can be habits in them, by which they are well or ill disposed in regard to something.
Reply to Objection: 1. The powers of the nutritive part have not an inborn aptitude to obey the command of reason, and therefore there are no habits in them. But the sensitive powers have an inborn aptitude to obey the command of reason; and therefore habits can be in them: for in so far as they obey reason, in a certain sense they are said to be rational, as stated in Ethic. i, 13.
2. The sensitive powers of dumb animals do not act at the command of reason; but if they are left to themselves, such animals act from natural instinct: and so in them there are no habits ordained to operations. There are in them, however, certain dispositions in relation to nature, as health and beauty. But whereas by man's reason brutes are disposed by a sort of custom to do things in this or that way, so in this sense, to a certain extent, we can admit the existence of habits in dumb animals: wherefore Augustine says (Questions. lxxxiii, qu. 36): "We find the most untamed beasts, deterred by fear of pain, from that wherein they took the keenest pleasure; and when this has become a custom in them, we say that they are tame and gentle." But the habit is incomplete, as to the use of the will, for they have not that power of using or of refraining, which seems to belong to the notion of habit: and therefore, properly speaking, there can be no habits in them.
3. The sensitive appetite has an inborn aptitude to be moved by the rational appetite, as stated in De Anima iii, text. 57: but the rational powers of apprehension have an inborn aptitude to receive from the sensitive powers. And therefore it is more suitable that habits should be in the powers of sensitive appetite than in the powers of sensitive apprehension, since in the powers of sensitive appetite habits do not exist except according as they act at the command of the reason. And yet even in the interior powers of sensitive apprehension, we may admit of certain habits whereby man has a facility of memory, thought or imagination: wherefore also the Philosopher says (De Memor. et Remin. ii) that "custom conduces much to a good memory": the reason of which is that these powers also are moved to act at the command of the reason.On the other hand the exterior apprehensive powers, as sight, hearing and the like, are not susceptible of habits, but are ordained to their fixed acts, according to the disposition of their nature, just as the members of the body, for there are no habits in them, but rather in the powers which command their movements.
Objection: 1. It would seem that there are no habits in the intellect. For habits are in conformity with operations, as stated above (Article ). But the operations of man are common to soul and body, as stated in De Anima i, text. 64. Therefore also are habits. But the intellect is not an act of the body (De Anima iii, text. 6). Therefore the intellect is not the subject of a habit.
2. Further, whatever is in a thing, is there according to the mode of that in which it is. But that which is form without matter, is act only: whereas what is composed of form and matter, has potentiality and act at the same time. Therefore nothing at the same time potential and actual can be in that which is form only, but only in that which is composed of matter and form. Now the intellect is form without matter. Therefore habit, which has potentiality at the same time as act, being a sort of medium between the two, cannot be in the intellect; but only in the "conjunction," which is composed of soul and body.
3. Further, habit is a disposition whereby we are well or ill disposed in regard to something, as is said (Metaph. v, text. 25). But that anyone should be well or ill disposed to an act of the intellect is due to some disposition of the body: wherefore also it is stated (De Anima ii, text. 94) that "we observe men with soft flesh to be quick witted." Therefore the habits of knowledge are not in the intellect, which is separate, but in some power which is the act of some part of the body.
On the contrary The Philosopher (Ethic. vi, 2,3,10) puts science, wisdom and understanding, which is the habit of first principles, in the intellective part of the soul.
I answer that concerning intellective habits there have been various opinions. Some, supposing that there was only one "possible" [*I 79,2, ad 2] intellect for all men, were bound to hold that habits of knowledge are not in the intellect itself, but in the interior sensitive powers. For it is manifest that men differ in habits; and so it was impossible to put the habits of knowledge directly in that, which, being only one, would be common to all men. Wherefore if there were but one single "possible" intellect of all men, the habits of science, in which men differ from one another, could not be in the "possible" intellect as their subject, but would be in the interior sensitive powers, which differ in various men.Now, in the first place, this supposition is contrary to the mind of Aristotle. For it is manifest that the sensitive powers are rational, not by their essence, but only by participation (Ethic. i, 13). Now the Philosopher puts the intellectual virtues, which are wisdom, science and understanding, in that which is rational by its essence. Wherefore they are not in the sensitive powers, but in the intellect itself. Moreover he says expressly (De Anima iii, text. 8,18) that when the "possible" intellect "is thus identified with each thing," that is, when it is reduced to act in respect of singulars by the intelligible species, "then it is said to be in act, as the knower is said to be in act; and this happens when the intellect can act of itself," i.e. by considering: "and even then it is in potentiality in a sense; but not in the same way as before learning and discovering." Therefore the "possible" intellect itself is the subject of the habit of science, by which the intellect, even though it be not actually considering, is able to consider. In the second place, this supposition is contrary to the truth. For as to whom belongs the operation, belongs also the power to operate, belongs also the habit. But to understand and to consider is the proper act of the intellect. Therefore also the habit whereby one considers is properly in the intellect itself.
Reply to Objection: 1. Some said, as Simplicius reports in his Commentary on the Predicaments, that, since every operation of man is to a certain extent an operation of the "conjunctum," as the Philosopher says (De Anima i, text. 64); therefore no habit is in the soul only, but in the "conjunctum." And from this it follows that no habit is in the intellect, for the intellect is separate, as ran the argument, given above. But the argument is no cogent. For habit is not a disposition of the object to the power, but rather a disposition of the power to the object: wherefore the habit needs to be in that power which is principle of the act, and not in that which is compared to the power as its object.Now the act of understanding is not said to be common to soul and body, except in respect of the phantasm, as is stated in De Anima, text. 66. But it is clear that the phantasm is compared as object to the passive intellect (De Anima iii, text. 3,39). Whence it follows that the intellective habit is chiefly on the part of the intellect itself; and not on the part of the phantasm, which is common to soul and body. And therefore we must say that the "possible" intellect is the subject of habit, which is in potentiality to many: and this belongs, above all, to the "possible" intellect. Wherefore the "possible" intellect is the subject of intellectual habits.
2. As potentiality to sensible being belongs to corporeal matter, so potentiality to intellectual being belongs to the "possible" intellect. Wherefore nothing forbids habit to be in the "possible" intellect, for it is midway between pure potentiality and perfect act.
3. Because the apprehensive powers inwardly prepare their proper objects for the "possible intellect," therefore it is by the good disposition of these powers, to which the good disposition of the body cooperates, that man is rendered apt to understand. And so in a secondary way the intellective habit can be in these powers. But principally it is in the "possible" intellect.
Objection: 1. It would seem that there is not a habit in the will. For the habit which is in the intellect is the intelligible species, by means of which the intellect actually understands. But the will does not act by means of species. Therefore the will is not the subject of habit.
2. Further, no habit is allotted to the active intellect, as there is to the "possible" intellect, because the former is an active power. But the will is above all an active power, because it moves all the powers to their acts, as stated above (Question , Article ). Therefore there is no habit in the will.
3. Further, in the natural powers there is no habit, because, by reason of their nature, they are determinate to one thing. But the will, by reason of its nature, is ordained to tend to the good which reason directs. Therefore there is no habit in the will.
On the contrary Justice is a habit. But justice is in the will; for it is "a habit whereby men will and do that which is just" (Ethic. v, 1). Therefore the will is the subject of a habit.
I answer that Every power which may be variously directed to act, needs a habit whereby it is well disposed to its act. Now since the will is a rational power, it may be variously directed to act. And therefore in the will we must admit the presence of a habit whereby it is well disposed to its act. Moreover, from the very nature of habit, it is clear that it is principally related to the will; inasmuch as habit "is that which one uses when one wills," as stated above (Article ).
Reply to Objection: 1. Even as in the intellect there is a species which is the likeness of the object; so in the will, and in every appetitive power there must be something by which the power is inclined to its object; for the act of the appetitive power is nothing but a certain inclination, as we have said above (Question , Article ; Question , Article ). And therefore in respect of those things to which it is inclined sufficiently by the nature of the power itself, the power needs no quality to incline it. But since it is necessary, for the end of human life, that the appetitive power be inclined to something fixed, to which it is not inclined by the nature of the power, which has a relation to many and various things, therefore it is necessary that, in the will and in the other appetitive powers, there be certain qualities to incline them, and these are called habits.
2. The active intellect is active only, and in no way passive. But the will, and every appetitive power, is both mover and moved (De Anima iii, text. 54). And therefore the comparison between them does not hold; for to be susceptible of habit belongs to that which is somehow in potentiality.
3. The will from the very nature of the power inclined to the good of the reason. But because this good is varied in many ways, the will needs to be inclined, by means of a habit, to some fixed good of the reason, in order that action may follow more promptly.
Objection: 1. It would seem that there are no habits in the angels. For Maximus, commentator of Dionysius (Coel. Hier. vii), says: "It is not proper to suppose that there are intellectual (i.e. spiritual) powers in the divine intelligences (i.e. in the angels) after the manner of accidents, as in us: as though one were in the other as in a subject: for accident of any kind is foreign to them." But every habit is an accident. Therefore there are no habits in the angels.
2. Further, as Dionysius says (Coel. Hier. iv): "The holy dispositions of the heavenly essences participate, above all other things, in God's goodness." But that which is of itself [per se] is prior to and more power than that which is by another [per aliud]. Therefore the angelic essences are perfected of themselves unto conformity with God, and therefore not by means of habits. And this seems to have been the reasoning of Maximus, who in the same passage adds: "For if this were the case, surely their essence would not remain in itself, nor could it have been as far as possible deified of itself."
3. Further, habit is a disposition (Metaph. v, text. 25). But disposition, as is said in the same book, is "the order of that which has parts." Since, therefore, angels are simple substances, it seems that there are no dispositions and habits in them.
On the contrary Dionysius says (Coel. Hier. vii) that the angels are of the first hierarchy are called: "Fire-bearers and Thrones and Outpouring of Wisdom, by which is indicated the godlike nature of their habits."
I answer that Some have thought that there are no habits in the angels, and that whatever is said of them, is said essentially. Whence Maximus, after the words which we have quoted, says: "Their dispositions, and the powers which are in them, are essential, through the absence of matter in them." And Simplicius says the same in his Commentary on the Predicaments: "Wisdom which is in the soul is its habit: but that which is in the intellect, is its substance. For everything divine is sufficient of itself, and exists in itself."Now this opinion contains some truth, and some error. For it is manifest from what we have said (Question , Article ) that only a being in potentiality is the subject of habit. So the above-mentioned commentators considered that angels are immaterial substances, and that there is no material potentiality in them, and on that account, excluded from them habit and any kind of accident. Yet since though there is no material potentiality in angels, there is still some potentiality in them (for to be pure act belongs to God alone), therefore, as far as potentiality is found to be in them, so far may habits be found in them. But because the potentiality of matter and the potentiality of intellectual substance are not of the same kind. Whence, Simplicius says in his Commentary on the Predicaments that: "The habits of the intellectual substance are not like the habits here below, but rather are they like simple and immaterial images which it contains in itself."However, the angelic intellect and the human intellect differ with regard to this habit. For the human intellect, being the lowest in the intellectual order, is in potentiality as regards all intelligible things, just as primal matter is in respect of all sensible forms; and therefore for the understanding of all things, it needs some habit. But the angelic intellect is not as a pure potentiality in the order of intelligible things, but as an act; not indeed as pure act (for this belongs to God alone), but with an admixture of some potentiality: and the higher it is, the less potentiality it has. And therefore, as we said in the I 55,1, so far as it is in potentiality, so far is it in need of habitual perfection by means of intelligible species in regard to its proper operation: but so far as it is in act, through its own essence it can understand some things, at least itself, and other things according to the mode of its substance, as stated in De Causis: and the more perfect it is, the more perfectly will it understand.But since no angel attains to the perfection of God, but all are infinitely distant therefrom; for this reason, in order to attain to God Himself, through intellect and will, the angels need some habits, being as it were in potentiality in regard to that Pure Act. Wherefore Dionysius says (Coel. Hier. vii) that their habits are "godlike," that is to say, that by them they are made like to God.But those habits that are dispositions to the natural being are not in angels, since they are immaterial.
Reply to Objection: 1. This saying of Maximus must be understood of material habits and accidents.
2. As to that which belongs to angels by their essence, they do not need a habit. But as they are not so far beings of themselves, as not to partake of Divine wisdom and goodness, therefore, so far as they need to partake of something from without, so far do they need to have habits.
3. In angels there are no essential parts: but there are potential parts, in so far as their intellect is perfected by several species, and in so far as their will has a relation to several things.
Summa Th. I-II EN Qu.49 a.3