SECOND ARTICLE [I-II, Q. 49, Art. 2]

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.

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Summa Theologica, Part I-II (Pars Prima Secundae) From the Complete American Edition · 第 328 / 746 题