Summa Theologiae Moralis, vol. I: De Principiis

S. Th. I-II, q. 49; Q. D. de Virt. 1, a. 1.

559. Habit (ἕξις, hexis) is named from the verb to have, whence it signifies a quality or mode by which a thing is disposed in such or such a way in itself or in relation to another. In many ways however something can be disposed; whence the meaning of the word is restricted to indicate only the first species of quality, i.e. the mode by which a thing is disposed in relation to its nature and consequently to its end, and therefore well or ill; namely a perfect and permanent mode which adheres firmly to the thing and therefore is with difficulty lost: thus it is distinguished from a simple disposition which is a mode easily lost by which a thing is disposed in relation to its nature. Habit is therefore a quality difficult to move, according to which the subject is well or ill disposed in itself or in relation to another; — or a stable disposition determining the subject to being well or ill disposed in itself or in relation to operation, in being or in operating.

« Habit, says S. Thomas, C. G. IV, 77, differs from potency in this, that by potency we are able to do something, but by habit we are not rendered able to do something, but fit or unfit for what we are able to do well or ill. By habit therefore there is not given nor taken away from us a certain ability, but this we acquire by habit, that we do something well or ill ».

560. Habit is divided a) into good and evil habit, according as it is a mode agreeing with nature or not agreeing;

b) into substantive or entitative, and operative, according as it is a mode by which nature is well or ill disposed in itself, with respect to being, — or by which it is well or ill disposed in relation to another, with respect to its operation, or by which it is disposed to act suitably or not suitably to its end.

The former immediately inheres in the substance and is principally ordered to being, and not to operating, except mediately inasmuch as being itself is ordered to operating: such are beauty, health, sickness, and sanctifying grace; — the other immediately inheres in an operative potency and therefore is immediately ordered to operation: such are fitness and unfitness, knowledge and art, virtue and vice. « Something is well or ill disposed in two ways: namely in itself or by relation to something. As that which is healthy is well disposed in itself, but that which is robust is well disposed to do something » S. Thom., in V Metaph. lect. 20.

561. Necessity of habits. — That there are operative habits is established by experience: for operations at first very difficult afterward become very easy, as is evident from one who plays the cithara, or dances, or writes, or reads, or studies science, or exercises himself in temperance or drunkenness. — They are necessary in those things which are indifferent: for habit is good or evil; whence nothing has a habit except what can in many and diverse ways be disposed in relation to its nature in itself or to operation. Therefore habits inhere in those things which 1) are in potency, 2) to many, diverse, contrary things, and therefore 3) in many or diverse ways can and ought to be disposed well or ill to their nature or operation. These three conditions are required for this, that something needs a habit. Hence:

1°) There is no habit in God, because in no way is he in potency, but he is his own being and his own operation, and accordingly can be disposed to nothing beyond himself.

2°) Neither is there habit in potencies altogether determined to one thing, because they are sufficient for the act determined and cannot be determined in more ways, nor be more or better or less well disposed; whence the forces of nature do not acquire a habit by their exercise, but always act as much as they can.

3°) But habits are in potencies which are not altogether determined to one thing, and therefore do not have all the propensity which they could have to operation, but to this they can be proportioned in diverse ways. By habit such a potency acquires greater inclination, and so constancy, facility, and pleasure in perfecting its acts. Which mode becomes as it were connatural to it, and therefore it is called habit second nature.

Whence operative habit can be defined: A quality difficult to move by which man is disposed to operating easily, promptly, and delightfully¹; — or a permanent quality superadded to an operative potency and facilitating and inclining it to operating either well or ill, i.e. suitably or not suitably to the end.

562. Observations. — 1°a. From the aforesaid definition it follows:

a) an operative habit is the first (proximate) act of the potency, and the operation is the second act (q. 49, a. 3, ad 1);

b) habit is the mean between pure operative potency (remote first act) and perfect act (operation, second act);

c) habit does not give the potency the ability to operate, but that it operates perfectly, i.e. constantly and uniformly, — promptly, easily, and expeditely, — and delightfully (Q. D. de Virt. 1, a. 1; C. G. IV, 77);

d) an operative habit is truly and properly found in an active potency which properly operates; in a merely passive potency however through which the active operates, it is not found except improperly and secondarily, inasmuch as there is rather a passive quality which this potency easily serves the active potency (q. 50, a. 1).

2°a. An operative habit, while it is in an indifferent potency, does not however completely remove its indifference, nor therefore necessitate it to act; whence S. Thomas says that one uses a habit when one wishes (q. 49, a. 3 sed contra; q. 50, a. 3, ad 2; a. 5).

S. Th. I-II, q. 50.

563. Natural entitative habit is not found in the soul, because this is the complete form of human nature, and therefore it cannot be disposed to something perfect according to nature; but there can be found in it a supernatural habit by which it participates a higher nature: thus by sanctifying grace it participates the divine nature. — In the body however there is found a natural entitative habit by which it is more or less perfect in its being: such are health, sickness, beauty, deformity, leanness, etc.

564. Principle. Operative habit is in an indifferent operative potency i.e. not altogether determined to one. — It is proved:

1°) It is in an operative potency. For an operative habit is that which immediately determines to operation; but that must be determined to operation which is the principle of operation.

2°) It is in an indifferent potency. For what can be disposed in itself in many ways can be ordered and determined to acting in diverse ways.

Hence it is in the potencies of the soul which can operate in diverse ways:

1°) in the will which, as being a rational potency, can be ordered to acting in diverse ways and to the determined good of reason, and of itself is indifferent to acting well or ill;

2°) in the intellect which is in potency to all intelligibles, and undetermined to things not evident;

3°) in the sensitive potencies, not indeed when they operate from the instinct of nature (thus they are determined to one), but when they operate by the command of reason, according as they can be ordered to diverse things and well or ill disposed. Since however

a) the sensitive appetite operates more by the command of reason (and thus is more indifferent) than the internal senses, it follows that habits are found more in the sensitive appetite;

b) nevertheless habits are found in the internal senses, by which man is well disposed for memory, or thought, or imagination; but

c) they are not found in the external senses, because by nature they are altogether determined to one.

565. Properly so called operative habits are not in the potencies of the body, which properly do not operate, but are mere instruments of the soul. For:

a) An operative habit of itself is not in the potencies of the body, namely the exterior members, or the vegetative forces, or the motive forces according to place, because by nature they are determined to one.

b) Inasmuch however as they are moved by the soul, even in them and in the external senses, properly operative habits cannot be, because they properly do not operate, but are mere instruments of the soul which principally operates in them and which they obey at its nod.

c) But they are said to be in them secondarily, because in them there can be passive qualities and dispositions by which they are more disposed for promptly serving the operations of the soul. As e.g. the motive forces insofar as the nerves are relaxed or contracted; the vegetative forces as by use they become adapted for abstinence or for the use of determined food.

S. Th. I-II, q. 51, 52, 53; q. 63, a. 1 and 2; De Virt. q. 1, a. 8 and 9.

566. Principle I. One operative habit of the soul is in man from nature, not indeed totally (then it would be innate) but partially and according to a beginning, namely the habit of first principles, inasmuch as, the terms being known through intelligible species (which are not in us from nature), at once the facility results of seeing that the terms agree with each other or not.

567. Principle II. Other habits are caused in the soul from the human acts proper to the agent, namely from the acts of the moving potency in the moved potency of the same agent¹; thus e.g. the act of the appetitive virtue proceeds from an apprehension representing the object, the intellective power as reasoning has the active principle of self-evident propositions, the possible intellect is moved by the agent intellect. For the agent in which there is at the same time the active and passive principle of its act, inasmuch as it is active can cause the habit, and inasmuch as it is passive can receive it and be perfected by it.

They are acquired habits².

Sometimes by one act the habit is caused, when the active potency by one act totally overcomes the passive potency, as happens in the habit of science because one act suffices for conviction³; — ordinarily however from acts of the same species repeated, as happens in the habit of opinion, in the habits of the internal senses, and especially in the moral virtues and vices, because reason by one act cannot make that the appetite is ordinarily, and generally, and in all circumstances good or evil, as is required for virtue or vice.

568. Principle III. Other habits are caused by God, namely supernatural ones by which we are disposed to a supernatural end exceeding the capacity of human nature; likewise God can also cause habits which by our acts we can acquire, as he gave some the knowledge of the Scriptures or of languages.

They are infused habits of themselves, or accidentally.

569. Principle IV. No habit is innate. — Supernatural habits are in no way in us from nature; — nor are acquired habits from nature according to essence, perfection, and consummation; but only according to a certain aptitude and beginning, and indeed in two ways.

a) On the part of the soul, not according to the beginning of the habit itself, but only according to aptitude or as to its principles, inasmuch as the intellect and will naturally say the order and inclination to the knowledge of truth and love of good, and thus the habits of first principles in the intellect and the natural inclination of the will to good are the principles or seeds from which intellectual and moral virtues are generated⁴. But « because the inclination to proper objects, which seems to be the beginning of habit, does not pertain to the habit but rather to the very notion of the potencies » (q. 51, a. 1), therefore it is not the beginning of the habit itself according to itself, but only according to its principles or according to its aptitude in causes.

b) On the part of the body and internal senses, also according to the beginning of the habit itself, inasmuch as because of their disposition man is helped or impeded for good, and thus is better or less well disposed for certain habits: thus from the disposition of the organs and complexion of the body, one is more disposed for understanding than another, or has a propensity for certain virtues (chastity, fortitude, meekness) or vices (anger, lust). Thus he has greater aptitude for receiving such or such a habit and will more easily acquire it⁵.

Moreover habits of the body can be caused by one act, if the producing cause is of great strength, as health from one strong medicine, organic deformation from one passion, e.g. a great terror.

570. Principle V. Habits are increased, but not by addition of a new degree: for if added, two or more would be added, whence there would be more habits and thus more accidents of the same species in the same subject, which is repugnant (e.g. two charities, two temperances, two arts); nor would the former habit truly become greater and be increased, but rather be multiplied. But they are increased

1°) according to themselves: extensively, inasmuch as the same habit in number extends itself to new objects to which it was not before ordered; as theological knowledge is extended by the study of a new treatise;

2°) on the part of the subject: intensively, inasmuch as the same habit is more received and adheres more firmly in the subject, and reduces it more to act; and accordingly the potency in which the habit resides more participates the character of habit, whence it tends more expeditely and promptly to act; as knowledge of the same treatise which becomes clearer. And indeed:

a) Habits are increased intensively by the same cause by which they are produced: for similar acts cause habits not only in species but also in degree and similar intensity; whence an act more intense or equally intense as the habit increases it or at least disposes to increase; but when the will does not use the habit totally and produces a less intense act, that act rather disposes to the diminution of the habit and does not increase it.

b) Habits are increased extensively by acts about another part of the object: he who already has knowledge of all the treatises of theology, one excepted, increases the habit by the study of that part.

571. Principle VI. Habits are corrupted of themselves or accidentally: accidentally, when the subject in which the habit is, is corrupted; of themselves i.e. by their contrary. It is to be noted that every habit which is acquired by one act, is corrupted by one act; but that which is acquired by many acts, is not corrupted except by many, but by one only is diminished.

Of themselves those habits which have no contrary are not corrupted, as the habit of principles. Those which have a contrary can be corrupted of themselves, as science and opinion by an opposite principle or by a sophistic deduction; and acquired moral virtue by contrary judgments of practical reason from ignorance, passion, or malice; likewise habits of the body.

Habits of the intellect and will are not corrupted accidentally, because these faculties are incorruptible; but habits of the sensitive potencies and of the body are corrupted, as temperance before the resurrection.

572. Principle VII. Habits are diminished intensively and extensively from the same cause by which they are corrupted of themselves, i.e. by their contrary, because diminution is the way to corruption.

Moreover some habits are also diminished and corrupted by the mere cessation from act, not indeed directly of themselves, but indirectly accidentally, namely by the removal of the hindrance, inasmuch as this cessation takes away the acts which prevented contraries from corrupting or diminishing the habit of themselves.

S. Th. I-II, q. 54 and 56, a. 2.

573. There are several rules according to which habits are distinguished in species (a. 2):

1°a) As forms are distinguished by reason of the cause: Habits are specifically distinguished whose proper and of themselves causes are diverse, for every agent produces something like itself according to species. Thus habits which are acquired by diverse acts are distinguished; likewise acquired habits which we acquire by our acts, and infused of themselves which God alone can give us.

2°a) As habits are distinguished by reason of nature: Habits are specifically distinguished which signify a diverse order to nature (and consequently to the end), as good and evil habits, or which signify order to a diverse nature, as ordinary human virtue and divine or heroic virtue which is fitting to a higher nature.

3°a) As operative habits are distinguished by reason of the object: Habits are specifically distinguished which have diverse formal objects: for habits are dispositions to acts; if therefore acts are specifically distinguished according to objects, so also habits. — This is the chief rule, because it indicates the ultimate species.

The three aforesaid rules are fundamental; from the last however follows a derived rule, namely:

4°a) That habits are consequently distinguished by reason of the subject: Habits are specifically distinguished which are in diverse potencies principally operating. For the potencies themselves are distinguished by generically distinct objects. Whence where the potencies are diverse, also the objects are diverse¹.

574. Corollaries. — 1°o. From the third rule it follows that habits of diverse species can be in one and the same potency, because a potency can be ordered to diverse objects.

2°o. The fourth rule of specific distinction by reason of the subject or potency is to be understood of potencies which principally operate. For those which operate secondarily, serving the principal act or disposing to it, adhere to the object of the principal operation, and therefore the secondary habits which are in them take their species from this object: thus the operation of art in the hand takes its species from the object of the art which is in the intellect.

3°o. Hence one habit or one virtue cannot be equally and according to essence in several potencies; it can however pertain to several potencies in a certain order, so that it is principally in one, and extends itself secondarily to others: whether by way of diffusion according as one potency moves another which serves it, e.g. justice commands the passions or temperance; or by way of disposition according as one receives from another, e.g. prudence rectifying the choice of means supposes the rectitude of the appetite, about the end (q. 66, a. 2).