OF HABITS IN GENERAL, AS TO THEIR SUBSTANCE (In Four Articles) After treating of human acts and passions, we now pass on to the consideration of the principles of human acts, and firstly of intrinsic principles, secondly of extrinsic principles. The intrinsic principle is power and habit; but as we have treated of powers in the First Part (Q. 77, seqq.), it remains for us to consider them in general: in the second place we shall consider virtues and vices and other like habits, which are the principles of human acts.
Concerning habits in general there are four points to consider: First, the substance of habits; second, their subject; third, the cause of their generation, increase, and corruption; fourth, how they are distinguished from one another.
Under the first head, there are four points of inquiry: (1) Whether habit is a quality?
(2) Whether it is a distinct species of quality?
(3) Whether habit implies an order to an act?
(4) Of the necessity of habit.
Whether Habit Is a Quality?
Objection 1: It would seem that habit is not a quality. For Augustine says (QQ. lxxxiii, qu. 73): "this word 'habit' is derived from the verb 'to have.'" But "to have" belongs not only to quality, but also to the other categories: for we speak of ourselves as "having" quantity and money and other like things. Therefore habit is not a quality.
Obj. 2: Further, habit is reckoned as one of the predicaments; as may be clearly seen in the _Book on the Predicaments_ (Categor. vi). But one predicament is not contained under another. Therefore habit is not a quality.
Obj. 3: Further, "every habit is a disposition," as is stated in the _Book of the Predicaments_ (Categor. vi). Now disposition is "the order of that which has parts," as stated in _Metaph._ v, text. 24.
But this belongs to the predicament Position. Therefore habit is not a quality.
_On the contrary,_ The Philosopher says in the Book of Predicaments (Categor. vi) that "habit is a quality which is difficult to change."
_I answer that,_ This word _habitus_ (habit) is derived from _habere_ (to have). Now habit is taken from this word in two ways; in one way, inasmuch as man, or any other thing, is said to "have" something; in another way, inasmuch as a particular thing has a relation (_se habet_) either in regard to itself, or in regard to something else.
Concerning the first, we must observe that "to have," as said in regard to anything that is "had," is common to the various predicaments. And so the Philosopher puts "to have" among the "post-predicaments," so called because they result from the various predicaments; as, for instance, opposition, priority, posterity, and such like. Now among things which are had, there seems to be this distinction, that there are some in which there is no medium between the "haver" and that which is had: as, for instance, there is no medium between the subject and quality or quantity. Then there are some in which there is a medium, but only a relation: as, for instance, a man is said to have a companion or a friend. And, further, there are some in which there is a medium, not indeed an action or passion, but something after the manner of action or passion: thus, for instance, something adorns or covers, and something else is adorned or covered: wherefore the Philosopher says (Metaph. v, text. 25) that "a habit is said to be, as it were, an action or a passion of the haver and that which is had"; as is the case in those things which we have about ourselves. And therefore these constitute a special genus of things, which are comprised under the predicament of "habit": of which the Philosopher says (Metaph. v, text. 25) that "there is a habit between clothing and the man who is clothed."
But if "to have" be taken according as a thing has a relation in regard to itself or to something else; in that case habit is a quality; since this mode of having is in respect of some quality: and of this the Philosopher says (Metaph. v, text. 25) that "habit is a disposition whereby that which is disposed is disposed well or ill, and this, either in regard to itself or in regard to another: thus health is a habit." And in this sense we speak of habit now.
Wherefore we must say that habit is a quality.
Reply Obj. 1: This argument takes "to have" in the general sense: for thus it is common to many predicaments, as we have said.
Reply Obj. 2: This argument takes habit in the sense in which we understand it to be a medium between the haver, and that which is had: and in this sense it is a predicament, as we have said.
Reply Obj. 3: Disposition does always, indeed, imply an order of that which has parts: but this happens in three ways, as the Philosopher goes on at once to says (Metaph. v, text. 25): namely, "either as to place, or as to power, or as to species." "In saying this," as Simplicius observes in his _Commentary on the Predicaments,_ "he includes all dispositions: bodily dispositions, when he says 'as to place,'" and this belongs to the predicament "Position," which is the order of parts in a place: "when he says 'as to power,' he includes all those dispositions which are in course of formation and not yet arrived at perfect usefulness," such as inchoate science and virtue: "and when he says, 'as to species,' he includes perfect dispositions, which are called habits," such as perfected science and virtue.
Whether Habit Is a Distinct Species of Quality?
Objection 1: It would seem that habit is not a distinct species of quality. Because, as we have said (A. 1), habit, in so far as it is a quality, is "a disposition whereby that which is disposed is disposed well or ill." But this happens in regard to any quality: for a thing happens to be well or ill disposed in regard also to shape, and in like manner, in regard to heat and cold, and in regard to all such things. Therefore habit is not a distinct species of quality.
Obj. 2: Further, the Philosopher says in the _Book of the Predicaments_ (Categor. vi), that heat and cold are dispositions or habits, just as sickness and health. Therefore habit or disposition is not distinct from the other species of quality.
Obj. 3: Further, "difficult to change" is not a difference belonging to the predicament of quality, but rather to movement or passion.
Now, no genus should be contracted to a species by a difference of another genus; but "differences should be proper to a genus," as the Philosopher says in _Metaph._ vii, text. 42. Therefore, since habit is "a quality difficult to change," it seems not to be a distinct species of quality.
_On the contrary,_ The Philosopher says in the _Book of the Predicaments_ (Categor. vi) that "one species of quality is habit and disposition."
_I answer that,_ The Philosopher in the _Book of Predicaments_ (Categor. vi) reckons disposition and habit as the first species of quality. Now Simplicius, in his _Commentary on the Predicaments,_ explains the difference of these species as follows. He says "that some qualities are natural, and are in their subject in virtue of its nature, and are always there: but some are adventitious, being caused from without, and these can be lost. Now the latter," i.e. those which are adventitious, "are habits and dispositions, differing in the point of being easily or difficultly lost. As to natural qualities, some regard a thing in the point of its being in a state of potentiality; and thus we have the second species of quality: while others regard a thing which is in act; and this either deeply rooted therein or only on its surface. If deeply rooted, we have the third species of quality: if on the surface, we have the fourth species of quality, as shape, and form which is the shape of an animated being." But this distinction of the species of quality seems unsuitable. For there are many shapes, and passion-like qualities, which are not natural but adventitious: and there are also many dispositions which are not adventitious but natural, as health, beauty, and the like. Moreover, it does not suit the order of the species, since that which is the more natural is always first.
Therefore we must explain otherwise the distinction of dispositions and habits from other qualities. For quality, properly speaking, implies a certain mode of substance. Now mode, as Augustine says (Gen. ad lit. iv, 3), "is that which a measure determines": wherefore it implies a certain determination according to a certain measure.
Therefore, just as that in accordance with which the material potentiality (_potentia materiae_) is determined to its substantial being, is called quality, which is a difference affecting the substance, so that, in accordance with the potentiality of the subject is determined to its accidental being, is called an accidental quality, which is also a kind of difference, as is clear from the Philosopher (Metaph. v, text. 19).
Now the mode o[r] determination of the subject to accidental being may be taken in regard to the very nature of the subject, or in regard to action, and passion resulting from its natural principles, which are matter and form; or again in regard to quantity. If we take the mode or determination of the subject in regard to quantity, we shall then have the fourth species of quality. And because quantity, considered in itself, is devoid of movement, and does not imply the notion of good or evil, so it does not concern the fourth species of quality whether a thing be well or ill disposed, nor quickly or slowly transitory.
But the mode o[r] determination of the subject, in regard to action or passion, is considered in the second and third species of quality.
And therefore in both, we take into account whether a thing be done with ease or difficulty; whether it be transitory or lasting. But in them, we do not consider anything pertaining to the notion of good or evil: because movements and passions have not the aspect of an end, whereas good and evil are said in respect of an end.
On the other hand, the mode or determination of the subject, in regard to the nature of the thing, belongs to the first species of quality, which is habit and disposition: for the Philosopher says (Phys. vii, text. 17), when speaking of habits of the soul and of the body, that they are "dispositions of the perfect to the best; and by perfect I mean that which is disposed in accordance with its nature."
And since the form itself and the nature of a thing is the end and the cause why a thing is made (Phys. ii, text. 25), therefore in the first species we consider both evil and good, and also changeableness, whether easy or difficult; inasmuch as a certain nature is the end of generation and movement. And so the Philosopher (Metaph. v, text. 25) defines habit, a "disposition whereby someone is disposed, well or ill"; and in _Ethic._ ii, 4, he says that by "habits we are directed well or ill in reference to the passions."
For when the mode is suitable to the thing's nature, it has the aspect of good: and when it is unsuitable, it has the aspect of evil.
And since nature is the first object of consideration in anything, for this reason habit is reckoned as the first species of quality.
Reply Obj. 1: Disposition implies a certain order, as stated above (A. 1, ad 3). Wherefore a man is not said to be disposed by some quality except in relation to something else. And if we add "well or ill," which belongs to the essential notion of habit, we must consider the quality's relation to the nature, which is the end. So in regard to shape, or heat, or cold, a man is not said to be well or ill disposed, except by reason of a relation to the nature of a thing, with regard to its suitability or unsuitability. Consequently even shapes and passion-like qualities, in so far as they are considered to be suitable or unsuitable to the nature of a thing, belong to habits or dispositions: for shape and color, according to their suitability to the nature of thing, concern beauty; while heat and cold, according to their suitability to the nature of a thing, concern health. And in this way heat and cold are put, by the Philosopher, in the first species of quality.
Wherefore it is clear how to answer the second objection: though some give another solution, as Simplicius says in his _Commentary on the Predicaments._ Reply Obj. 3: This difference, "difficult to change," does not distinguish habit from the other species of quality, but from disposition. Now disposition may be taken in two ways; in one way, as the genus of habit, for disposition is included in the definition of habit (Metaph. v, text. 25): in another way, according as it is divided against habit. Again, disposition, properly so called, can be divided against habit in two ways: first, as perfect and imperfect within the same species; and thus we call it a disposition, retaining the name of the genus, when it is had imperfectly, so as to be easily lost: whereas we call it a habit, when it is had perfectly, so as not to be lost easily. And thus a disposition becomes a habit, just as a boy becomes a man. Secondly, they may be distinguished as diverse species of the one subaltern genus: so that we call dispositions, those qualities of the first species, which by reason of their very nature are easily lost, because they have changeable causes; e.g.
sickness and health: whereas we call habits those qualities which, by reason of their very nature, are not easily changed, in that they have unchangeable causes, e.g. sciences and virtues. And in this sense, disposition does not become habit. The latter explanation seems more in keeping with the intention of Aristotle: for in order to confirm this distinction he adduces the common mode of speaking, according to which, when a quality is, by reason of its nature, easily changeable, and, through some accident, becomes difficultly changeable, then it is called a habit: while the contrary happens in regard to qualities, by reason of their nature, difficultly changeable: for supposing a man to have a science imperfectly, so as to be liable to lose it easily, we say that he is disposed to that science, rather than that he has the science. From this it is clear that the word "habit" implies a certain lastingness: while the word "disposition" does not.
Nor does it matter that thus to be easy and difficult to change are specific differences (of a quality), although they belong to passion and movement, and not the genus of quality. For these differences, though apparently accidental to quality, nevertheless designate differences which are proper and essential to quality. In the same way, in the genus of substance we often take accidental instead of substantial differences, in so far as by the former, essential principles are designated.
Whether Habit Implies Order to an Act?
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.
Obj. 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.
Obj. 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 Obj. 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 Reply Obj. 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.
Reply Obj. 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.
Whether Habits Are Necessary?
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.
Obj. 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.
Obj. 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 (AA. 2, 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 First Part (Q. 56, A. 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 (A. 1, 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 Obj. 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.
Reply Obj. 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.
Reply Obj. 3: The same habit has not a relation to good and evil, as will be made clear further on (Q. 54, A. 3): whereas the same power has a relation to good and evil. And, therefore, habits are necessary that the powers be determined to good.
QUESTION 50 OF THE SUBJECT OF HABITS (In Six Articles) 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?
Whether There Is a Habit in the Body?
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.
Obj. 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.
Obj. 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 (Q. 49, AA. 2 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 (Q. 49, A. 4) 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 Obj. 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.
Reply Obj. 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.
Reply Obj. 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 (Q. 49, A. 2, 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.
Whether the Soul Is the Subject of Habit in Respect of Its Essence or in Respect of Its Power?
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 (Q.
49, A. 2). 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.
Obj. 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 First Part (Q. 77, A. 1, ad 5).
Therefore habit is not in the soul in respect of its powers.
Obj. 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 (Q. 49, AA. 2, 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 2 Pet. 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 (Q. 110, A. 4).
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 (Q. 49, A.
4). 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 Obj. 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.
Reply Obj. 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.
Reply Obj. 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.
Whether There Can Be Any Habits in the Powers of the Sensitive Part?
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.
Obj. 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 (Q.
49, A. 3). Therefore there are no habits in the sensitive powers.
Obj. 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: