Cursus Philosophicus Thomisticus, Secunda Pars Artis Logicae

Aristotle defines quality in ch. 8¹ as “that by which we are said to be qualified.” Some simply reject this definition: first, because it seems tautological, as if whiteness were said to be that by which we are said to be white; but that is just what needs to be explained. Second, because it seems circular: just as quality is defined by our being qualified, so, conversely, a qualified thing is defined as that which has a quality, which is to commit a circle. Finally, because the definition is no better known than what is defined; for quality in the abstract and a qualified thing in the concrete are equally unknown.

Nevertheless, this definition should not be rejected, since it was handed down by Aristotle and received by his entire school. In the first place, since the highest genera lack a genus and a difference, this is not a definition but a description, and it is given through effects that are better known.

We can consider the effects of quality in two ways. In one way, from the standpoint of state, insofar as it is taken in the abstract or in the concrete, because the state of concretion is better known and more perceptible to us. St. Thomas explains the definition in this way in Opusculum 48, treatise on Quality, ch. 1². This way of defining, however, would not fit other definitions so well, in which the highest genera are not defined.

In a second way, the effect of quality can be considered by reason of the form itself. Among all the accidents, it is proper to quality to make a subject formed and qualified, as St. Thomas notes from the Philosopher in Metaphysics V, lect. 16³, since of all the accidents quality most properly ennobles and qualifies its subject. Quantity quantifies the subject and tends instead to materialize it by extending and ordering its material parts. The other categories either order a subject to something else, as relation does, or depend on something extrinsic that orders them, as do the last six categories, as we shall say in the next question. Quality alone is given for ennobling or qualifying a subject, or for the contrary of ennoblement and qualification. Something is said to qualify a thing through what is actual and determines it in the manner of a form. An essential difference is therefore said to be predicated in the mode of a qualification, because it contracts and determines the genus, which is potential, and by determining it forms and qualifies it. What an essential difference does essentially, quality does accidentally: namely, it forms and qualifies what is potential and unformed, and does so primarily and of itself. For although other accidents also perfect and actualize a subject, they do not have this as their primary and proper function; rather, they either quantify matter, order the subject to something extrinsic, or depend on something extrinsic for their denomination. Therefore it is rightly said that quality is that by which we are said to be qualified—that is, formed, qualified, and ennobled.

To the first objection, the answer is that this definition is not tautological and does not explain the same by the same, either because it explains the state of concretion as better known, or because it explains the special effect of this accident, which is to qualify and ennoble; by it, then, we are said to be qualified.

To the second objection, the answer is that these definitions do not form a circle, because they are not definitions but descriptions. Likewise, the abstract and the concrete stand in different genera of cause: one explains the form, the other connotes the subject. Finally, quality in the abstract is not explained only through concretion, but through the effect of ennobling and making a thing qualified. When a qualified thing is defined, however, it is defined only with regard to the state of the concrete, by its having a form. Hence no circle is committed.

To the last objection, we say that the definition is not given through something equally unknown, because it is given through the effects of qualifying and through the state of concretion in a subject, which are better known to us than the qualifying form itself or its state of abstraction. It follows less still that the thing defined is placed in its own definition, because quality in the abstract is defined by its effects, not by quality itself.

FROM THESE POINTS YOU WILL GATHER that St. Thomas expressed the account of quality better than the competing views, saying in Summa Theologiae I, q. 28, a. 2 that “quality is called a disposition of substance,” and again in I–II, q. 49, a. 2, that “quality implies a certain mode of substance, and a mode is that which measure prescribes.” Hence it implies a certain determination according to some measure. Therefore, the proper account of quality is said to consist in mode or determination insofar as “mode” is taken to mean formation and proper disposition. “Disposition” here is not taken for the first species of quality, but generally, as is said in Metaphysics V, lect. 20 according to St. Thomas⁴: “disposition is the order of that which has parts.” Hence we gather that it belongs to quantity and quality to order parts, but not the same parts or in the same way. Quantity orders material parts by way of extension, so that one is placed outside another, first in relation to itself and then in relation to place. Quality, however, orders nonmaterial parts, not by way of extension but by way of power or perfection, according to the due or undue commensuration, whether in relation to the nature itself or the termination of its quantity, in relation to an action or the term of an action, as we shall explain for each species in turn, or also in relation to the intensification of a quality or the extension of a habit. In a word, whatever involves due commensuration and proportion, whether in bodily or spiritual things, and whether with respect to parts of power or formal parts, is called a disposition by quality. Quantity, by contrast, merely places material parts outside one another, which is to extend them, not to dispose them properly and duly; for its formation with respect to termination occurs through figure, which is a quality. This seems the more probable explanation of a matter as obscure and varied as quality.

Aristotle posited four pairs of species in the division of this category: the first is habit and disposition, the second power and lack of power, the third affection and affective quality, the fourth form and figure.

Concerning these, THE QUESTION IS ABOUT THE SOUNDNESS AND ADEQUACY OF THIS DIVISION. The common opinion is that this division is adequate; there is, however, disagreement about how these species are gathered together and what account should be given of them. Scotus, on the chapter on Quality, question 1, gathers them in this way: Quality in itself is a certain disposition of substance. Therefore it is either interior or exterior. If exterior, it is either per se and primarily sensible or not. If it is per se and primarily sensible, it belongs to the third species, which is called affection or affective quality. But if it is an interior disposition, it either disposes as an innate principle of operation, and thus is a power or lack of power, or it is a principle of operation that is not innate but comes from outside, and thus is the first species, habit or disposition.

Other more recent authors gather them in this way: Quality is ordered either to adorn substance or to act. If to act, it either comes as a principle of operation or as its term. If as a principle, it is either an implanted and intrinsic principle or one coming from outside. If intrinsic, it is a power or lack of power. If it comes from outside, it is a habit; or, if it is the term of an operation, it will belong to disposition, as do the terms of cognition, which are concepts. But if it is ordered to perfecting or adorning substance, it either serves to preserve and sustain the substance itself, and thus is the third species, or to perfect extension, and thus is the fourth.

These accounts nevertheless fail in many ways. First, they proceed by accounts that are very extrinsic and in themselves quite uncertain: for example, that quality inheres only in the surface, or also within; that it is primarily and per se sensible; that every habit or disposition is called an operative quality, or even that every power is. For a passive power is not operative; grace, health, and beauty, which belong to the first species, are not operative either. Nor is disposition only the term of an immanent operation, as a concept is, since there are also qualities that are easily changeable by their nature and are not terms of an immanent act as such, such as opinion or vice, a passing illness, and so on. Finally, the fact that quality, speaking generally, adorns substance does not explain why this should not also belong to quantity, which likewise adorns by extending, since it orders. Conversely, why should adorning substance by sustaining and preserving it not belong to the first species, disposition, which, if it disposes its subject well, sustains and preserves it—especially since health, which most of all preserves an animal, is placed in the first species by the Philosopher in Physics 7, text 17¹ and by St. Thomas, 1. 2. q. 50. art. 1?

Divus Thomas, then, gathers these species differently, in 1. 2. q. 49. art. 2. Since quality implies an accident, whose proper function is to impose an accidental determination and mode on a subject, and every mode and determination can be considered either in relation to the very nature or according to action and passion, which follow upon the principles of nature, or in relation to quantity, the mode according to quantity belongs to the fourth species, which is form and figure: figure results from the termination of quantity. The mode of a subject according to action and passion is considered in the second or third species of quality. For power is per se ordered to action or passion, whereas affection or affective quality results from some affection or motion. A mode and determination in conformity with the nature of a thing, however, belongs to habit and disposition, because these are first and per se ordered to the suitability or unsuitability of a nature; and because nature is the term of generation and motion, while motion is followed by ease or difficulty of coming to be, these accounts too are considered in habit and disposition.

AGAINST THIS ACCOUNT, HOWEVER, YOU WILL OBJECT that, according to it, there will be no impossibility in placing the same quality in two species. For example, heat, insofar as it is caused by condensation, is an affection or affective quality; yet, insofar as it is suitable to a nature, as it is in fire, it will be the first species of quality.

Again, Divus Thomas proceeds obscurely in distinguishing the second and third species of quality. For he says that a mode according to action and passion belongs to the second and third species of quality. But he does not explain how it belongs to one and to the other, or distinguishes the second from the third. Nor is it enough to assign what is easily or with difficulty changed, what is transient or lasting; these are not per se differences and do not apply equally to the second and third species, nor do they distinguish powers and lacks of power from one another.

Again, habit and disposition also function as a determination or mode in relation to action, since operative habits are principles for eliciting an operation. Therefore not every habit is to be explained by its suitability to the subject.

Finally, to constitute the third species of quality by its being the term of an operation or motion seems a very accidental condition of quality, indeed an insufficient one. For if only qualities that terminate a motion of alteration are said to belong to the third species, it follows that light produced in the air, which comes to be without alteration, does not belong to the third species of quality; this is commonly denied. But if qualities that terminate every motion, even an instantaneous one, belong to it, it follows that immanent acts and concepts produced by them, and intentional species, will belong to the third species of quality, even though they are commonly placed in the first.

To the first objection it is answered that no quality belongs to more than one essential species, although with respect to its state and accidental mode it can take on the mode and state of another; it does not do so essentially. This frequently happens among these qualities: one takes on the mode of another with respect to state and accidental mode. Thus a disposition can, from an extrinsic cause, become difficult to change, not because of its intrinsic principles; and a habit can, because its state is imperfect, be easily changed, since it has not yet been perfectly acquired. Heat likewise is per se and primarily the term of alteration, but accidentally and from an extrinsic cause it has the mode of suitability or unsuitability to a nature, insofar as it is the proper affection of something—not because it is ordered to that by its formal account, or because the due temperament arises from it, as health does, which expresses suitability to a nature. Conversely, it can primarily and per se express suitability to a nature, while accidentally or as a consequence being the term of an action. Thus it is not placed essentially in two species: it is essentially in one, and has the mode or state of another. This is how St. Thomas is to be understood in 1. 2. q. 49. art. 2. ad 1., and it follows from q. 50. art. 1. ad 3. at the end.

What, in the case of each particular quality, is primary and per se, and what is accidental and secondary, is to be judged either from the effects of the quality—for example, if we see that one formal character is always found in a quality, as being the term of alteration is found in heat, while another is not always found, the latter is an accidental state—or from the principles by which the quality is caused. That is, if by those principles it is ordered to action or passion, to suitability or unsuitability to a nature, and so forth, then this is essential to it.

To the second objection it is said that the distinction between the second and third species is not stated expressly by Divus Thomas there, but is drawn from what he teaches in Metaphysics 5, lect. 16²: that affections of mobile subjects, according to which bodies are changed by alteration, belong to the third species of quality. Therefore the third species of quality is that which belongs to a subject through alteration, or to a subject insofar as it is moved, taking alteration broadly for every physical change of quality. Power and lack of power, however, which constitute the second species, belong to a subject as a principle of action or passion, primarily and per se, but not to a subject insofar as it has been altered; for powers do not presuppose alteration in order to belong to a subject. In the second species, “easily” and “with difficulty changeable” are not taken as they are in the first, but as explaining the force of resisting or yielding to an active agent: thus they constitute active or passive power, since what is passive yields easily, and what is active resists with difficulty. Lasting and quickly passing qualities, however, belong not to the second but to the third species.

To the third objection it is said that habit and disposition are primarily and per se for disposing a nature according to suitability and unsuitability. If the nature is active and is disposed toward action, this is not because habits are primarily and per se active, but because the nature they dispose is active and is suitably disposed only toward action, as we shall say in the following article from Divus Thomas, 1. 2. q. 49. art. 3.

To the final objection it is said, first, that being the term of alteration is not extraneous to quality. Since there is a per se motion toward quality, namely alteration, as is said in Physics 5³, some qualities must per se be qualities of a subject insofar as it is moved and altered. Next, we say that in this third species are placed qualities that primarily and per se terminate motion, or are qualities of a subject insofar as it has been altered, even by instantaneous alteration or change, as in the case of illumination in the air. Yet immanent acts or concepts will not for that reason belong to the third species, as light does, because they do not change the subject or constitute terms of alteration, which is found properly only in bodily things. Rather, they have another, prior, and more principal consideration: suitably disposing a nature insofar as it is cognizing. Thus they belong to the first species of quality, and this account is more principal in them because it is proper and per se; immanent acts, however, have alteration accidentally, as occurs in the senses on the part of the organs.

From what has been said it is clear that this division is adequate and sufficient.

To the first species, besides habits and dispositions, which are plainly such, are reduced all immanent acts and concepts, indeed even impressed species, which seem to be numbered among habits by St. Thomas, 1. 2. q. 50. art. 16. For in them there is the character of a good or bad disposition of a power, insofar as the object is represented well or badly. Grace also belongs to this species, as St. Thomas teaches in 1. 2. q. 110. art. 3. ad 3., as do supernatural habits, because they are given to elevate a power and thus presuppose it, although, in the order of elevation, they provide it with the whole power for an act that has no being except as elevated.

To the second species are reduced all instrumental powers, because they are given for acting simply or for assisting a power, not for disposing a nature well or badly. Therefore St. Thomas, 3. p. q. 63. art. 2., reduces character to this species, because it is not given for acting well or badly, but for validly and truly receiving or performing the sacraments. Finally, some reduce rough and smooth, rare and dense, to the different arrangement of the parts alone, because rough things have parts arranged unequally, smooth things equally; rare things have parts more spread out, dense things more contracted and in a smaller space. All this pertains to position. This is indeed true in itself. But because hardness is sometimes joined to roughness, and some softness to smoothness, which Aristotle in this chapter⁴ numbers among the qualities, these are also commonly called qualities on account of this concomitant feature.

But is this division essential? The answer is affirmative. Quality is a highest genus and must have species essentially distinct beneath it, and no others can be assigned. Certainly, there is no doubt that specific distinction intervenes among some qualities, as between habit, power, and figure; indeed, it intervenes among some belonging to the same pair, as between two habits or two powers. One might only doubt because sometimes the same quality seems to belong to two species, as heat belongs to the third because it is the term of alteration, and to the first because it is suitable to some nature. But we have already said above that it belongs per se to only one, according to the formal character that per se and always belongs to something, or according to the principles from which it arises per se. Thus it always belongs to heat to be the term of alteration, but not always to dispose a nature. Therefore, if it sometimes has this second feature, that is accidental to it, not essential or primarily and per se belonging to it, and hence not constitutive of its species.

FIRST SPECIES.

The first species is habit and disposition. Several meanings of HABIT are commonly distinguished, but all are reduced to two heads: “habit” or “to have” is spoken of predicatively and postpredicatively. Postpredicatively it is the same as a mode of possession, and Aristotle counts eight modes in the final chapter.¹ Predicatively, in one sense, it signifies the last predicament, namely being clothed and putting on clothing. In another sense, it signifies a certain species of quality, according to which someone is well or badly disposed.

Likewise, DISPOSITION can be taken generally: in this sense it is the ordering of something having parts, as the Philosopher says in Metaphysics V, text 24.² It can thus also be found in quantity and in position. Second, it is taken specifically for being well or badly disposed; for from the manner in which parts are possessed, it commonly happens that something is well or badly disposed. There is, however, this difference between habit and disposition: something is called a habit when it is held and possessed firmly; otherwise, strictly speaking, we do not have it. A disposition, since by its kind it is a tendency toward the form to which it disposes and orders something, does not yet possess the form firmly and perfectly. Hence habit is called a quality difficult to move, and disposition one easy to move.

Two DIFFICULTIES arise here. The first concerns the generic account: is this first species an operative quality? The second concerns the differential accounts: do habit and disposition differ essentially?

On the first point, many think that habit consists in being an operative principle that is added rather than innate; in this they distinguish it from the second species, which is an innate principle of operation.

Nevertheless, St. Thomas teaches the opposite in I–II, q. 49, a. 2. The REASON may be given generally: some qualities of this species are not operative, such as health and beauty, which the Philosopher expressly places in the first species in Physics VII, text 17,³ as cited by St. Thomas in I–II, q. 50, a. 1; likewise grace among supernatural things. It is proved specifically that even habit, when operative, is not primarily and of itself a principle of operation, but of disposing nature well or badly; yet because nature is an operative power, it ought to be well disposed in operating. The reason is that, as the Philosopher says in the cited place, habits of both soul and body are dispositions of what is perfected toward the best. “Perfected” means disposed according to nature. Since nature and form are ends for whose sake something is done, the first species therefore considers good and bad: good is understood according to the account of an end. Thus, through habit and disposition something is said to be held well or badly—that is, suitably in relation to form and end. Hence habit and disposition can have an operative character, because the end of nature is operation or its product, or because the nature disposed by habit is an active power suitably ordered to its operation. Habit is therefore said to be given not simply for acting, but for acting in a certain way, suitably or unsuitably: although it influences the substance of the act, it does so not as the first principle of operation, which is a power, but as presupposing the power and disposing it suitably.

On the second point, Scotus (q. 9 of this predicament) and many others think habit and disposition differ only accidentally; St. Thomas, q. 7 of De malo, a. 2, ad 4, favors this opinion.⁴ The BASIS is that the very same numerically identical entity is called a habit when held firmly in a subject, and a disposition when it is not held firmly. Thus the Philosopher teaches concerning knowledge in this chapter On Quality⁵ that when it is retained in a subject only briefly, it is not a habit but a disposition; when it becomes more lasting, it is a habit.

This is confirmed because “easy” and “difficult to move from a subject” are differences also found in other genera and differences, as with passion and passible quality, or slow and swift motion, which are said to persist long or pass quickly. Therefore they cannot be essential differences of this first species; an essential difference is not found outside its own essence.

Nevertheless, St. Thomas himself and the Thomists generally hold the opposite, in I–II, q. 49, a. 2, ad 3, where he says: “Disposition can be understood as divided against habit in two ways. In one way, as the perfect and imperfect within the same species: disposition retains the common name when it is present imperfectly, while habit is so called when it is present perfectly, so that it is not easily lost; in this way disposition becomes habit, as a boy becomes a man. In another way, they can be distinguished as different subordinate species of one genus: those qualities of the first species are called dispositions which, by their proper account, are easily lost because they have changeable causes. Such are sickness and health. Habits, however, are those qualities which by their account are not easily changed, because they have unchangeable causes, as knowledge and virtues. On this account disposition does not become habit, and this seems more consonant with Aristotle’s intention.” So St. Thomas, who teaches the same in the De malo question cited above,⁶ although he also admits the contrary opinion, without settling the matter here as he does in this passage.

From this it follows what it is for something by its nature to be easy or difficult to move—a point the authors of the opposing view investigate and press so anxiously. We say that being difficult to move by nature means having, from one’s own and intrinsic principles, causes that are not easily changed. Cajetan, explaining this in the chapter On Quality, said that sometimes a quality by its species requires causes of difficult change; sometimes it is difficult to change because of an individual condition, since this subject has some disposition or cause of persistence, although the nature of the quality itself does not require it. Thus “easy to move” and “difficult to move” do not mean the same as lasting a long or short time, for duration is accidental. A disposition can last a long time and a habit a short time: since duration is continuation in being and depends on extrinsic preserving causes, something that by itself does not require unchangeable and persistent causes may often find in a particular subject a cause or disposition that preserves it for a long time. Examples are light in air, if the luminous body remains for a long time; an act of seeing, if the will remains engaged in seeing; and an ordinary illness, if someone takes no medicine but eats food contrary to health. Therefore the account of habit does not consist in being difficult to remove, nor does disposition consist in actually changing easily; rather, a disposition is easy to move, by reference to its intrinsic causes, not because some extrinsic factor accidentally makes it last or not last in actuality. Thus knowledge is intrinsically a habit, because it proceeds from evident and firm causes; and so are virtues, because they proceed from practical principles known and directed by synderesis. Opinion and vice, by contrast, have causes of easy change by their very nature: the former is against reason, the latter accompanied by fear of reason.

I know that some seek other accounts of this essential distinction: for example, that what is easy to move depends on its agent in coming to be and in being preserved, while what is difficult to move does not depend on it for preservation; or that habit lacks a contrary whereas disposition has one. These accounts are empty. We see many dispositions last even when their agent is absent, yet differ specifically from habit—for example, sickness, vice, and opinion, which persist in the agent’s absence. Conversely, infused virtues such as grace and charity depend on their proper agent for coming to be and being preserved, as light depends on the sun, as St. Thomas teaches in II–II, q. 24, a. 12, and yet they are habits. Likewise, some habits have a contrary: knowledge has error, virtue has vice, and so on.

BUT YOU WILL OBJECT: According to St. Thomas’s view, it follows that an act of demonstration is a habit, since it is generated from immutable principles, namely principles evident and certain in themselves. It also follows that there is no habit of opinion or vice; nor will impressed species be habits, contrary to St. Thomas, I–II, q. 50, a. 6, since none of these have immutable causes.

We reply that an act of demonstration, or any other act, does not have immutable causes, because an actual operation consists in its very proceeding, not in some thing produced. Operation is changeable of itself, because it is in process and coming to be, not a completed product, even if it concerns some immutable object. A habit, by contrast, is not exercise or operation, but a produced form that leaves the power immutably determined. As for opinion and vice, we judge it more probable that they are not habits, because by their nature they do not have firm adherence, but are accompanied by fear, although through repeated acts they can acquire firmness with respect to accidental manner and state. St. Thomas sometimes teaches that an opinionative habit is generated from repeated acts, as in I–II, q. 51, a. 3, and q. 53, a. 1. But he speaks of habit with respect to manner, not essence: since opinion, by the force of its species, lacks immutable principles, it may be individually fixed in some subject through an extrinsic cause, but is not simply a habit. The same must be said of vice insofar as it has a morality contrary to reason and thus lacks firm principles, although it can become fixed in the sensitive appetite on the side of sensible good, and so be firm in a qualified sense. Hence it is one thing for opinion to have the manner of a habit—that is, duration—and knowledge not to; it is another for it to have the nature of a habit, that is, firmness by its intrinsic nature and principles.

AS TO THE FIRST ARGUMENT, we deny that one and the same entity can by its nature and intrinsic principles be both habit and disposition; it can be so only with respect to state. The Philosopher commonly gave examples in terms of firmness or ease on the part of state because that is more familiar, thereby leading us from it to the less evident point, which concerns the force of nature. Thus St. Thomas, I–II, q. 50, a. 1, ad 2, says that the Philosopher called health a habit “as a habit,” as the Greek has it. In the same way he did not call sciences that are imperfectly possessed habits with respect to state, though he does not deny that they are habits by nature, as Cajetan also resolves in his commentary on this chapter On Quality.

To the confirmation we reply that “easy to move” and “difficult to move” are found primarily in motion itself, as St. Thomas says in I–II, q. 49, a. 2, ad 3. We use them, however, to describe the proper differences of quality by applying the names of motion, not motion itself. Easy and difficult to move are likewise found in other species of quality with respect to duration or ease, but not with respect to the intrinsic account of disposing a subject well or badly, which is essential to the first species.

SECOND SPECIES.

It is called power and impotence. By “power” we understand the proximate principle of operation by which a subject is constituted not for operating well or badly, but simply for truly performing the substance of the operation. The question how substance cannot operate by itself but needs a superadded quality as an eliciting principle in order to proceed to act belongs to the books On the Soul and to Metaphysics; one may consult St. Thomas, I, qq. 54 and 77. “Power” includes both active and passive power. The immanent operative powers—that is, powers receptive of what they elicit—show us that passive power exists in the genus of quality. Whether there is some quality, especially in the natural order, that is purely passive and in no way active is not for this place to discuss, but for Metaphysics V. Nor does it belong here to discuss a neutral power to act, so called because it lacks an inclination to act and is purely indifferent—not because it is neither active nor passive, as Scotus held, against whom Cajetan argues in Opuscula, vol. 3, tract 3, q. 1.

By “impotence” we do not mean a pure absence of power, but a weak and imperfect power, such as dullness of intellect, a weak power of generation, and the like. It is therefore clear that power and impotence, taken in this way, do not differ specifically simply by virtue of power and impotence as such: the same imperfect and weak power becomes perfect when its weakness is removed. There is no place here to distinguish, as with habit, immutability and firmness arising either from accidental state or from the inward and intrinsic principles of nature. For every power is like a proper attribute, arising and innate from the principles of nature; if it is a natural power, every power has intrinsic firmness. And since it is not acquired gradually, as a habit is, it does not have imperfect firmness on account of its state or imperfect acquisition—although it can be impeded and weakened by something extrinsic, in which case it is an impotence differing from power only extrinsically. It is true that a less perfect nature gives rise to a less perfect power, which in comparison with the power of another nature may seem an impotence. Strictly speaking, however, this is not an impotence, since it has the strength or capacity due to it within its own kind, although that is less than the power of another kind. An ant’s ability is less than a lion’s, for example, but what the ant has is not simply called impotence, since it is a power in its own kind; otherwise only supreme power would count as power.

From this it is clear how the first species of quality differs from the second. The first is not simply a principle of operation, but of suitably disposing nature, whether or not it is active; power, however, is simply a principle of acting or being acted upon. We have already said above how infused virtues are not powers but habits, and how character is reduced to power. This is not a matter for logic but for theology. As for why the Philosopher, when listing the species of quality in Metaphysics V⁷, omitted power, St. Thomas answers there, lect. 16,⁸ that he had treated power at greater length just before and explained it.

THIRD SPECIES.

It is passion and passible quality. Setting aside the various meanings of passion that the Philosopher lists in Metaphysics V, text 26,⁹ and that St. Thomas discusses there, lect. 20,¹⁰ passion here means a quality according to which alteration takes place. Although passion can be taken commonly for every reception of a form from some agent, and thus is the predicament of being acted upon, it is taken specifically for a passion involving some alteration and change. For we commonly say that something suffers when it is altered and removed from its disposition. This is why acts of the sensitive appetite are specifically called passions: they occur with some bodily change, as St. Thomas teaches in I–II, q. 22, a. 2. A property of a thing is also called a “proper passion” because the subject receives it as its own.

TWO THINGS, THEN, MUST BE EXPLAINED: First, what these species properly consist in; second, how passion and passible quality differ from one another.

Some say that this third species is a quality ordered to perfecting and adorning the subject, one that is neither power, habit, nor figure. But they do not explain what this quality is, only what it is not. Others say it consists in being a quality caused by alteration or causing alteration. St. Thomas supports this in Opusculum 48, On Quality, ch. 4,¹¹ in Metaphysics V, lect. 16,¹² and in I–II, q. 50, a. 1, ad 3. Others take this quality not in relation to alteration but insofar as it causes passion in sense, and so include only sensible qualities, by which the senses are naturally affected. This is the view in Scotus’s school. St. Thomas also supports it in III, q. 63, a. 2, ad 2, where he teaches that the qualities in this species are only sensible passions or sensible qualities. Finally, others, such as Cajetan in his commentary on this chapter On Quality, take passion and passible quality here to mean what is naturally apt to cause or be caused by a passion of the appetite. Insofar as it objectively arouses or incites these passions, it is called passion or passible quality. Some recent authors follow this view while omitting Cajetan’s name.

All these explanations are probable and do not differ greatly. Since acts of the sensitive appetite have two aspects—an immanent act, which is the more formal, and a bodily change, which is material—and receive the name “passion” from the latter, as St. Thomas teaches in the cited question 22 of I–II, qualities cannot be called passible solely by reference to the immanent act, but by reference to the alteration and bodily change that accompany that act of appetite. Hence this quality will be called passible primarily and more originally by reference to alteration, just as acts of appetite are called passions because an accompanying alteration is involved. The account of this third species, then, is better explained from St. Thomas, Metaphysics V, lect. 16¹³ and the cited Opusculum 48,¹⁴ as the quality of a subject insofar as it is moved and altered. Since all bodily alterations are perceptible by sense—at least by taste and touch, and some also only by sight, as illumination and coloration—it follows that only sensible qualities are said to be placed in this species, as St. Thomas said in the cited passage of III. Since alteration in quality precedes passion in sense, as its object, and once the passion of alteration is posited we can sufficiently understand what makes a quality passible or a passion, this quality’s account is derived primarily from alteration, namely from causing or being caused by it; from this it follows that it causes passion in sense.

As for the distinction between passion itself and passible quality, the common opinion is that they differ only accidentally, with respect to extrinsic causes of duration. For the redness caused by shame, which soon passes, and that caused by a good temperament, which lasts a long time, are specifically of the same account. But because passion passes quickly, Aristotle said that we are not denominated qualified by it: what passes does not give rise to a denomination simply, which requires a stable state.

FOURTH SPECIES.

It is called form and figure. FORM is taken in three ways: first, for substantial form, which simply gives being; second, for any informing act; third, for that suitable disposition of quantity by which some are said to be well-formed or beautiful.

FIGURE is taken in two ways: in one sense, for a sign, as in 1 Corinthians 10: “All these things happened to them in figure.” In a second sense, for the mode resulting from the termination of quantity. This may be intrinsic, as the figure of a hand in itself, and so is a quality; or extrinsic and positional, as the same hand, when folded or extended, presents a different positional figure. This second kind can vary while the first remains unchanged, or can even be removed altogether, as in the body of Christ in the Eucharist.

Here figure is taken in the second sense and form in the third. According to the common opinion, they differ only accidentally. Figure means the termination of quantity, or its mode, taken precisely and, as it were, mathematically. Form adds that this termination has due proportion, as a kind of beauty. Thus form is not abstracted from sensible qualities but is modified by them; figure formed, or made with proportion, is called form. It is properly found in artifacts: for example, the figure of a house or tower is called its form. On this, see St. Thomas, Physics VII, lect. 5.¹⁵

ORDERING OF THE PREDICAMENT OF QUALITY.

The most general genus is quality. It is divided immediately into four genera: habit and disposition, power and impotence, passion and passible quality, form and figure. Each of these genera is divided into various species, which we cannot pursue within each genus.

One point alone should be observed: ONLY IN THE LAST TWO GENERA are bodily qualities placed, because the third species is caused by alteration or causes it primarily and of itself. Form and figure, however, result from the termination of quantity.

IN THE FIRST TWO GENERA, HOWEVER, both bodily and spiritual qualities can be found. Habit, then, can be divided into operative and non-operative. The non-operative is divided into bodily, such as beauty and health, and spiritual, such as grace. The operative is likewise divided into sensible and spiritual. Sensible habits include the various habits of the sensitive appetite, such as temperance, fortitude, etc.; spiritual habits are intellectual or moral. Intellectual habits fall into five species: wisdom, knowledge, understanding, prudence, and art. Moral habit is divided into good and bad. Bad habit—if it truly is a habit—extends across all kinds of vice; good habit extends across all kinds of moral virtue, such as justice, religion, piety, etc. The corresponding supernatural virtues are numbered among these as well.

Power is divided into active and passive; active power into incorporeal and corporeal. Under corporeal power are vital and non-vital powers; under vital, sensory, vegetative, etc. Vegetative powers include nutrition and generation, etc. Under sensory powers are the interior and exterior senses and the sensitive appetite. Under incorporeal power are will and intellect, and, by reduction, supernatural power, namely character. Some also reduce impressed species to this genus because they complete the cognitive power. It is truer, however, that they do not give it a principle of operation, but dispose it on the side of the object; hence, when they are given permanently, they belong to habits, as St. Thomas holds in I–II, q. 50, aa. 5 and 6.