Question Three: On the Cause of Habits

St. Thomas, 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 inheres in man from nature, not indeed totally (for then it would be innate), but partially and according to an inchoation, namely, the habit of first principles, insofar as, once the terms have been known through intelligible species (which do not inhere in us by nature), there immediately flows forth the facility of seeing that the terms agree with one another or do not.

567. Principle II. Other habits are caused in the soul from human acts proper to the agent, namely, from acts of the moving power in the moved power of the same agent;¹ thus, for example, the act of the appetitive power proceeds from apprehension representing the object, the intellective power as reasoning has as an active principle a proposition known through itself, and the possible intellect is moved by the agent intellect. For an agent in which there is at once the active and passive principle of its act, insofar as it is active can cause a habit, and insofar as it is passive can receive that habit and be perfected by it.

¹ Also the same power can be moving and moved under a diverse respect.

They are acquired habits.²

² Cf. I-II, q. 51, a. 3, and De Virt., q. 1, a. 9, ad 10 and 11.

Sometimes a habit is caused by one act, when the acting power by one act totally overcomes the passive power, as happens in the habit of science, because one act suffices for conviction;³ - ordinarily, however, it is caused from repeated acts of the same species, as happens in an opinative habit, in habits of the internal senses, and especially in moral virtues and vices, because reason by one act cannot bring it about that the appetite be good or bad ordinarily, generally, and in all circumstances, as is nevertheless required for virtue or vice.

³ Thus as to the intellect, for "as to the lower apprehensive powers, it is necessary that the same acts be reiterated several times, so that something be firmly impressed on the memory." q. 51, a. 3.

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

They are habits infused per se, or per accidens.

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

a) On the part of the soul, not according to the inchoation of the habit itself, but only according to aptitude or as to its principles, insofar as the intellect and will naturally state an order and inclination to knowledge of the true and love of the good, and thus the habit of first principles in the intellect and the natural inclination of the will to the good are principles or seeds from which intellectual and moral virtues are generated.⁴ But "because the inclination to proper objects, which seems to be an inchoation of habit, does not pertain to habit but rather to the very account of the powers" (q. 51, a. 1), therefore it is not an inchoation of the habit itself according to itself, but only according to its principles or according to its aptitude in its causes.

⁴ Cf. q. 51, a. 1 and q. 63, a. 1.

b) On the part of the body and of the internal senses, also according to the inchoation of the habit itself, insofar as on account of their disposition man is helped or impeded toward good, and thus is disposed better or less well to certain habits: thus from the disposition of the organs and the complexion of the body, one man is more disposed to understanding than another, or has a propensity to certain virtues (chastity, fortitude, meekness) or vices (anger, lust). Thus he has a greater aptitude for receiving such and such a habit and acquires it more easily.⁵

⁵ Nevertheless they are not virtues or vices: for the soul can be unharmed, although the body is so disposed from natural complexion.

Moreover habits of the body can be caused by one act, if the producing cause was of great power, as health from one strong medicine, organic deformation from one passion, for example, from immense terror.

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

1. according to themselves: extensively, insofar as the same habit in number extends itself to new objects to which it was not previously ordered; as theological science is extended by the study of a new treatise;

2. on the part of the subject: intensively, insofar as the same habit is received more and inheres more firmly in the subject, and reduces it more into act; and consequently the power in which the habit resides participates more in the account of the habit, whence it tends to act more expeditiously and promptly; as the knowledge of the same treatise becomes clearer. And indeed:

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

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

571. Principle VI. Habits are corrupted per se or per accidens: per accidens, when the subject in which they inhere is corrupted; per se, that is, through their contrary. It should be noted that every habit which is acquired by one act is corrupted by one act; but that which is acquired by several acts is not corrupted except by several, though it is diminished by only one.

Habits which do not have a contrary, such as the habit of principles, are not corrupted per se. But those which have a contrary can be corrupted per se, as science and opinion through an opposite principle or through a sophistical deduction; and acquired moral virtue through contrary judgments of practical reason from ignorance, passion, or malice; likewise habits of the body.

Habits of the intellect and will are not corrupted per accidens, because these faculties are incorruptible; but habits of the sensitive powers 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 per se, that is, through a contrary, because diminution is the way to corruption.

Moreover, certain habits are also diminished and corrupted by cessation from act alone, not indeed directly per se, but indirectly per accidens, namely, through the removal of that which prevents, insofar as this cessation takes away the acts which would impede things contrary to the habit from corrupting or diminishing it per se.