Summa Th. II-II EN Qu.46
We must now consider folly which is opposed to wisdom; and under this head there are three points of inquiry:
(1) Whether folly is contrary to wisdom?
(2) Whether folly is a sin?
(3) To which capital sin is it reducible?
Objection: 1. It would seem that folly is not contrary to wisdom. For seemingly unwisdom is directly opposed to wisdom. But folly does not seem to be the same as unwisdom, for the latter is apparently about Divine things alone, whereas folly is about both Divine and human things. Therefore folly is not contrary to wisdom.
2. Further, one contrary is not the way to arrive at the other. But folly is the way to arrive at wisdom, for it is written (1Co 3,18): "If any man among you seem to be wise in this world, let him become a fool, that he may be wise." Therefore folly is not opposed to wisdom.
3. Further, one contrary is not the cause of the other. But wisdom is the cause of folly; for it is written (Jr 10,14): "Every man is become a fool for knowledge," and wisdom is a kind of knowledge. Moreover, it is written (Is 47,10): "Thy wisdom and thy knowledge, this hath deceived thee." Now it belongs to folly to be deceived. Therefore folly is not contrary to wisdom.
4. Further, Isidore says (Etym. x, under the letter S) that "a fool is one whom shame does not incite to sorrow, and who is unconcerned when he is injured." But this pertains to spiritual wisdom, according to Gregory (Moral. x, 49). Therefore folly is not opposed to wisdom.
On the contrary Gregory says (Moral. ii, 26) that "the gift of wisdom is given as a remedy against folly."
I answer that Stultitia [Folly] seems to take its name from "stupor"; wherefore Isidore says (Etym. x, under the letter of S): "A fool is one who through dullness [stuporem] remains unmoved." And folly differs from fatuity, according to the same authority (Etym. x), in that folly implies apathy in the heart and dullness in the senses, while fatuity denotes entire privation of the spiritual sense. Therefore folly is fittingly opposed to wisdom.For "sapiens" [wise] as Isidore says (Etym. x) "is so named from sapor [savor], because just as the taste is quick to distinguish between savors of meats, so is a wise man in discerning things and causes." Wherefore it is manifest that "folly" is opposed to "wisdom" as its contrary, while "fatuity" is opposed to it as a pure negation: since the fatuous man lacks the sense of judgment, while the fool has the sense, though dulled, whereas the wise man has the sense acute and penetrating.
Reply to Objection: 1. According to Isidore (Etym. x), "unwisdom is contrary to wisdom because it lacks the savor of discretion and sense"; so that unwisdom is seemingly the same as folly. Yet a man would appear to be a fool chiefly through some deficiency in the verdict of that judgment, which is according to the highest cause, for if a man fails in judgment about some trivial matter, he is not for that reason called a fool.
2. Just as there is an evil wisdom, as stated above (Question , Article , ad 1), called "worldly wisdom," because it takes for the highest cause and last end some worldly good, so too there is a good folly opposed to this evil wisdom, whereby man despises worldly things: and it is of this folly that the Apostle speaks.
3. It is the wisdom of the world that deceives and makes us foolish in God's sight, as is evident from the Apostle's words (1Co 3,19).
4. To be unconcerned when one is injured is sometimes due to the fact that one has no taste for worldly things, but only for heavenly things. Hence this belongs not to worldly but to Divine wisdom, as Gregory declares (Moral. x, 49). Sometimes however it is the result of a man's being simply stupid about everything, as may be seen in idiots, who do not discern what is injurious to them, and this belongs to folly simply.
Objection: 1. It would seem that folly is not a sin. For no sin arises in us from nature. But some are fools naturally. Therefore folly is not a sin.
2. Further, "Every sin is voluntary," according to Augustine (De Vera Relig. xiv). But folly is not voluntary. Therefore it is not a sin.
3. Further, every sin is contrary to a Divine precept. But folly is not contrary to any precept. Therefore folly is not a sin.
On the contrary It is written (Pr 1,32): "The prosperity of fools shall destroy them." But no man is destroyed save for sin. Therefore folly is a sin.
I answer that Folly, as stated above (Article ), denotes dullness of sense in judging, and chiefly as regards the highest cause, which is the last end and the sovereign good. Now a man may in this respect contract dullness in judgment in two ways. First, from a natural indisposition, as in the case of idiots, and such like folly is no sin. Secondly, by plunging his sense into earthly things, whereby his sense is rendered incapable of perceiving Divine things, according to 1Co 2,14, "The sensual man perceiveth not these things that are of the Spirit of God," even as sweet things have no savor for a man whose taste is infected with an evil humor: and such like folly is a sin.
Reply to Objection: 1. This suffices for the Reply to the First Objection.
2. Though no man wishes to be a fool, yet he wishes those things of which folly is a consequence, viz. to withdraw his sense from spiritual things and to plunge it into earthly things. The same thing happens in regard to other sins; for the lustful man desires pleasure, without which there is no sin, although he does not desire sin simply, for he would wish to enjoy the pleasure without sin.
3. Folly is opposed to the precepts about the contemplation of truth, of which we have spoken above (Question ) when we were treating of knowledge and understanding.
Objection: 1. It would seem that folly is not a daughter of lust. For Gregory (Moral. xxxi, 45) enumerates the daughters of lust, among which however he makes no mention of folly. Therefore folly does not proceed from lust.
2. Further, the Apostle says (1Co 3,19): "The wisdom of this world is foolishness with God." Now, according to Gregory (Moral. x, 29) "the wisdom of this world consists in covering the heart with crafty devices;" and this savors of duplicity. Therefore folly is a daughter of duplicity rather than of lust.
3. Further, anger especially is the cause of fury and madness in some persons; and this pertains to folly. Therefore folly arises from anger rather than from lust.
On the contrary It is written (Pr 7,22): "Immediately he followeth her," i.e. the harlot . . . "not knowing that he is drawn like a fool to bonds."
I answer that As already stated (Article ), folly, in so far as it is a sin, is caused by the spiritual sense being dulled, so as to be incapable of judging spiritual things. Now man's sense is plunged into earthly things chiefly by lust, which is about the greatest of pleasures; and these absorb the mind more than any others. Therefore the folly which is a sin, arises chiefly from lust.
Reply to Objection: 1. It is part of folly that a man should have a distaste for God and His gifts. Hence Gregory mentions two daughters of lust, pertaining to folly, namely, "hatred of God" and "despair of the life to come"; thus he divides folly into two parts as it were.
2. These words of the Apostle are to be understood, not causally but essentially, because, to wit, worldly wisdom itself is folly with God. Hence it does not follow that whatever belongs to worldly wisdom, is a cause of this folly.
3. Anger by reason of its keenness, as stated above (I-II 48,2 I-II 48,3 I-II 48,4), produces a great change in the nature of the body, wherefore it conduces very much to the folly which results from a bodily impediment. On the other hand the folly which is caused by a spiritual impediment, viz. by the mind being plunged into earthly things, arises chiefly from lust, as stated above.
After treating of the theological virtues, we must in due sequence consider the cardinal virtues. In the first place we shall consider prudence in itself; secondly, its parts; thirdly, the corresponding gift; fourthly, the contrary vices; fifthly, the precepts concerning prudence.
Under the first head there are sixteen points of inquiry:
(1) Whether prudence is in the will or in the reason?
(2) If in the reason, whether it is only in the practical, or also in the speculative reason?
(3) Whether it takes cognizance of singulars?
(4) Whether it is virtue?
(5) Whether it is a special virtue?
(6) Whether it appoints the end to the moral virtues?
(7) Whether it fixes the mean in the moral virtues?
(8) Whether its proper act is command?
(9) Whether solicitude or watchfulness belongs to prudence?
(10) Whether prudence extends to the governing of many?
(11) Whether the prudence which regards private good is the same in species as that which regards the common good?
(12) Whether prudence is in subjects, or only in their rulers?
(13) Whether prudence is in the wicked?
(14) Whether prudence is in all good men?
(15) Whether prudence is in us naturally?
(16) Whether prudence is lost by forgetfulness ?
Objection: 1. It would seem that prudence is not in the cognitive but in the appetitive faculty. For Augustine says (De Morib. Eccl. xv): "Prudence is love choosing wisely between the things that help and those that hinder." Now love is not in the cognitive, but in the appetitive faculty. Therefore prudence is in the appetitive faculty.
2. Further, as appears from the foregoing definition it belongs to prudence "to choose wisely." But choice is an act of the appetitive faculty, as stated above (I-II 13,1). Therefore prudence is not in the cognitive but in the appetitive faculty.
3. Further, the Philosopher says (Ethic. vi, 5) that "in art it is better to err voluntarily than involuntarily, whereas in the case of prudence, as of the virtues, it is worse." Now the moral virtues, of which he is treating there, are in the appetitive faculty, whereas art is in the reason. Therefore prudence is in the appetitive rather than in the rational faculty.
On the contrary Augustine says (Questions. lxxxiii, qu. 61): "Prudence is the knowledge of what to seek and what to avoid."
I answer that As Isidore says (Etym. x): "A prudent man is one who sees as it were from afar, for his sight is keen, and he foresees the event of uncertainties." Now sight belongs not to the appetitive but to the cognitive faculty. Wherefore it is manifest that prudence belongs directly to the cognitive, and not to the sensitive faculty, because by the latter we know nothing but what is within reach and offers itself to the senses: while to obtain knowledge of the future from knowledge of the present or past, which pertains to prudence, belongs properly to the reason, because this is done by a process of comparison. It follows therefore that prudence, properly speaking, is in the reason.
Reply to Objection: 1. As stated above (I 82,4) the will moves all the faculties to their acts. Now the first act of the appetitive faculty is love, as stated above (I-II 25,1 I-II 25,2). Accordingly prudence is said to be love, not indeed essentially, but in so far as love moves to the act of prudence. Wherefore Augustine goes on to say that "prudence is love discerning aright that which helps from that which hinders us in tending to God." Now love is said to discern because it moves the reason to discern.
2. The prudent man considers things afar off, in so far as they tend to be a help or a hindrance to that which has to be done at the present time. Hence it is clear that those things which prudence considers stand in relation to this other, as in relation to the end. Now of those things that are directed to the end there is counsel in the reason, and choice in the appetite, of which two, counsel belongs more properly to prudence, since the Philosopher states (Ethic. vi, 5,7,9) that a prudent man "takes good counsel." But as choice presupposes counsel, since it is "the desire for what has been already counselled" (Ethic. iii, 2), it follows that choice can also be ascribed to prudence indirectly, in so far, to wit, as prudence directs the choice by means of counsel.
3. The worth of prudence consists not in thought merely, but in its application to action, which is the end of the practical reason. Wherefore if any defect occur in this, it is most contrary to prudence, since, the end being of most import in everything, it follows that a defect which touches the end is the worst of all. Hence the Philosopher goes on to say (Ethic. vi, 5) that prudence is "something more than a merely rational habit," such as art is, since, as stated above (I-II 57,4) it includes application to action, which application is an act of the will.
Objection: 1. It would seem that prudence belongs not only to the practical, but also to the speculative reason. For it is written (Pr 10,23): "Wisdom is prudence to a man." Now wisdom consists chiefly in contemplation. Therefore prudence does also.
2. Further, Ambrose says (De Offic. i, 24): "Prudence is concerned with the quest of truth, and fills us with the desire of fuller knowledge." Now this belongs to the speculative reason. Therefore prudence resides also in the speculative reason.
3. Further, the Philosopher assigns art and prudence to the same part of the soul (Ethic. vi, 1). Now art may be not only practical but also speculative, as in the case of the liberal arts. Therefore prudence also is both practical and speculative.
On the contrary The Philosopher says (Ethic. vi, 5) that prudence is right reason applied to action. Now this belongs to none but the practical reason. Therefore prudence is in the practical reason only.
I answer that According to the Philosopher (Ethic. vi, 5) "a prudent man is one who is capable of taking good counsel." Now counsel is about things that we have to do in relation to some end: and the reason that deals with things to be done for an end is the practical reason. Hence it is evident that prudence resides only in the practical reason.
Reply to Objection: 1. As stated above (Question , Articles ,3), wisdom considers the absolutely highest cause: so that the consideration of the highest cause in any particular genus belongs to wisdom in that genus. Now in the genus of human acts the highest cause is the common end of all human life, and it is this end that prudence intends. For the Philosopher says (Ethic. vi, 5) that just as he who reasons well for the realization of a particular end, such as victory, is said to be prudent, not absolutely, but in a particular genus, namely warfare, so he that reasons well with regard to right conduct as a whole, is said to be prudent absolutely. Wherefore it is clear that prudence is wisdom about human affairs: but not wisdom absolutely, because it is not about the absolutely highest cause, for it is about human good, and this is not the best thing of all. And so it is stated significantly that "prudence is wisdom for man," but not wisdom absolutely.
2. Ambrose, and Tully also (De Invent. ii, 53) take the word prudence in a broad sense for any human knowledge, whether speculative or practical. And yet it may also be replied that the act itself of the speculative reason, in so far as it is voluntary, is a matter of choice and counsel as to its exercise; and consequently comes under the direction of prudence. On the other hand, as regards its specification in relation to its object which is the "necessary true," it comes under neither counsel nor prudence.
3. Every application of right reason in the work of production belongs to art: but to prudence belongs only the application of right reason in matters of counsel, which are those wherein there is no fixed way of obtaining the end, as stated in Ethic. iii, 3. Since then, the speculative reason makes things such as syllogisms, propositions and the like, wherein the process follows certain and fixed rules, consequently in respect of such things it is possible to have the essentials of art, but not of prudence; and so we find such a thing as a speculative art, but not a speculative prudence.
Objection: 1. It would seem that prudence does not take cognizance of singulars. For prudence is in the reason, as stated above (Articles ,2). But "reason deals with universals," according to Phys. i, 5. Therefore prudence does not take cognizance except of universals.
2. Further, singulars are infinite in number. But the reason cannot comprehend an infinite number of things. Therefore prudence which is right reason, is not about singulars.
3. Further, particulars are known by the senses. But prudence is not in a sense, for many persons who have keen outward senses are devoid of prudence. Therefore prudence does not take cognizance of singulars.
On the contrary The Philosopher says (Ethic. vi, 7) that "prudence does not deal with universals only, but needs to take cognizance of singulars also."
I answer that As stated above (Article , ad 3), to prudence belongs not only the consideration of the reason, but also the application to action, which is the end of the practical reason. But no man can conveniently apply one thing to another, unless he knows both the thing to be applied, and the thing to which it has to be applied. Now actions are in singular matters: and so it is necessary for the prudent man to know both the universal principles of reason, and the singulars about which actions are concerned.
Reply to Objection: 1. Reason first and chiefly is concerned with universals, and yet it is able to apply universal rules to particular cases: hence the conclusions of syllogisms are not only universal, but also particular, because the intellect by a kind of reflection extends to matter, as stated in De Anima iii.
2. It is because the infinite number of singulars cannot be comprehended by human reason, that "our counsels are uncertain" (Sg 9,14). Nevertheless experience reduces the infinity of singulars to a certain finite number which occur as a general rule, and the knowledge of these suffices for human prudence.
3. As the Philosopher says (Ethic. vi, 8), prudence does not reside in the external senses whereby we know sensible objects, but in the interior sense, which is perfected by memory and experience so as to judge promptly of particular cases. This does not mean however that prudence is in the interior sense as in its principle subject, for it is chiefly in the reason, yet by a kind of application it extends to this sense.
Objection: 1. It would seem that prudence is not a virtue. For Augustine says (De Lib. Arb. i, 13) that "prudence is the science of what to desire and what to avoid." Now science is condivided with virtue, as appears in the Predicaments (vi). Therefore prudence is not a virtue.
2. Further, there is no virtue of a virtue: but "there is a virtue of art," as the Philosopher states (Ethic. vi, 5): wherefore art is not a virtue. Now there is prudence in art, for it is written (2Ch 2,14) concerning Hiram, that he knew "to grave all sort of graving, and to devise ingeniously [prudenter] all that there may be need of in the work." Therefore prudence is not a virtue.
3. Further, no virtue can be immoderate. But prudence is immoderate, else it would be useless to say (Pr 23,4): "Set bounds to thy prudence." Therefore prudence is not a virtue.
On the contrary Gregory states (Moral. ii, 49) that prudence, temperance, fortitude and justice are four virtues.
I answer that As stated above (I-II 55,3; I-II 56,1) when we were treating of virtues in general, "virtue is that which makes its possessor good, and his work good likewise." Now good may be understood in a twofold sense: first, materially, for the thing that is good, secondly, formally, under the aspect of good. Good, under the aspect of good, is the object of the appetitive power. Hence if any habits rectify the consideration of reason, without regarding the rectitude of the appetite, they have less of the nature of a virtue since they direct man to good materially, that is to say, to the thing which is good, but without considering it under the aspect of good. On the other hand those virtues which regard the rectitude of the appetite, have more of the nature of virtue, because they consider the good not only materially, but also formally, in other words, they consider that which is good under the aspect of good.Now it belongs to prudence, as stated above (Article , ad 3; Article ) to apply right reason to action, and this is not done without a right appetite. Hence prudence has the nature of virtue not only as the other intellectual virtues have it, but also as the moral virtues have it, among which virtues it is enumerated.
Reply to Objection: 1. Augustine there takes science in the broad sense for any kind of right reason.
2. The Philosopher says that there is a virtue of art, because art does not require rectitude of the appetite; wherefore in order that a man may make right use of his art, he needs to have a virtue which will rectify his appetite. Prudence however has nothing to do with the matter of art, because art is both directed to a particular end, and has fixed means of obtaining that end. And yet, by a kind of comparison, a man may be said to act prudently in matters of art. Moreover in certain arts, on account of the uncertainty of the means for obtaining the end, there is need for counsel, as for instance in the arts of medicine and navigation, as stated in Ethic. iii, 3.
3. This saying of the wise man does not mean that prudence itself should be moderate, but that moderation must be imposed on other things according to prudence.
Objection: 1. It would seem that prudence is not a special virtue. For no special virtue is included in the definition of virtue in general, since virtue is defined (Ethic. ii, 6) "an elective habit that follows a mean appointed by reason in relation to ourselves, even as a wise man decides." Now right reason is reason in accordance with prudence, as stated in Ethic. vi, 13. Therefore prudence is not a special virtue.
2. Further, the Philosopher says (Ethic. vi, 13) that "the effect of moral virtue is right action as regards the end, and that of prudence, right action as regards the means." Now in every virtue certain things have to be done as means to the end. Therefore prudence is in every virtue, and consequently is not a special virtue.
3. Further, a special virtue has a special object. But prudence has not a special object, for it is right reason "applied to action" (Ethic. vi, 5); and all works of virtue are actions. Therefore prudence is not a special virtue.
On the contrary It is distinct from and numbered among the other virtues, for it is written (Sg 8,7): "She teacheth temperance and prudence, justice and fortitude."
I answer that Since acts and habits take their species from their objects, as shown above (I-II 1,3; I-II 18,2; I-II 54,2), any habit that has a corresponding special object, distinct from other objects, must needs be a special habit, and if it be a good habit, it must be a special virtue. Now an object is called special, not merely according to the consideration of its matter, but rather according to its formal aspect, as explained above (I-II 54,2, ad 1). Because one and the same thing is the subject matter of the acts of different habits, and also of different powers, according to its different formal aspects. Now a yet greater difference of object is requisite for a difference of powers than for a difference of habits, since several habits are found in the same power, as stated above (I-II 54,1). Consequently any difference in the aspect of an object, that requires a difference of powers, will "a fortiori" require a difference of habits.Accordingly we must say that since prudence is in the reason, as stated above (Article ), it is differentiated from the other intellectual virtues by a material difference of objects. "Wisdom," "knowledge" and "understanding" are about necessary things, whereas "art" and "prudence" are about contingent things, art being concerned with "things made," that is, with things produced in external matter, such as a house, a knife and so forth; and prudence, being concerned with "things done," that is, with things that have their being in the doer himself, as stated above (I-II 57,4). On the other hand prudence is differentiated from the moral virtues according to a formal aspect distinctive of powers, i.e. the intellective power, wherein is prudence, and the appetitive power, wherein is moral virtue. Hence it is evident that prudence is a special virtue, distinct from all other virtues.
Reply to Objection: 1. This is not a definition of virtue in general, but of moral virtue, the definition of which fittingly includes an intellectual virtue, viz., prudence, which has the same matter in common with moral virtue; because, just as the subject of moral virtue is something that partakes of reason, so moral virtue has the aspect of virtue, in so far as it partakes of intellectual virtue.
2. This argument proves that prudence helps all the virtues, and works in all of them; but this does not suffice to prove that it is not a special virtue; for nothing prevents a certain genus from containing a species which is operative in every other species of that same genus, even as the sun has an influence over all bodies.
3. Things done are indeed the matter of prudence, in so far as they are the object of reason, that is, considered as true: but they are the matter of the moral virtues, in so far as they are the object of the appetitive power, that is, considered as good.
Objection: 1. It would seem that prudence appoints the end to moral virtues. Since prudence is in the reason, while moral virtue is in the appetite, it seems that prudence stands in relation to moral virtue, as reason to the appetite. Now reason appoints the end to the appetitive power. Therefore prudence appoints the end to the moral virtues.
2. Further, man surpasses irrational beings by his reason, but he has other things in common with them. Accordingly the other parts of man are in relation to his reason, what man is in relation to irrational creatures. Now man is the end of irrational creatures, according to Polit. i, 3. Therefore all the other parts of man are directed to reason as to their end. But prudence is "right reason applied to action," as stated above (Article ). Therefore all actions are directed to prudence as their end. Therefore prudence appoints the end to all moral virtues.
3. Further, it belongs to the virtue, art, or power that is concerned about the end, to command the virtues or arts that are concerned about the means. Now prudence disposes of the other moral virtues, and commands them. Therefore it appoints their end to them.
On the contrary The Philosopher says (Ethic. vi, 12) that "moral virtue ensures the rectitude of the intention of the end, while prudence ensures the rectitude of the means." Therefore it does not belong to prudence to appoint the end to moral virtues, but only to regulate the means.
I answer that The end of moral virtues is human good. Now the good of the human soul is to be in accord with reason, as Dionysius declares (Div. Nom. iv). Wherefore the ends of moral virtue must of necessity pre-exist in the reason.Now, just as, in the speculative reason, there are certain things naturally known, about which is "understanding," and certain things of which we obtain knowledge through them, viz. conclusions, about which is "science," so in the practical reason, certain things pre-exist, as naturally known principles, and such are the ends of the moral virtues, since the end is in practical matters what principles are in speculative matters, as stated above (Question , Article , ad 2; I-II 13,3); while certain things are in the practical reason by way of conclusions, and such are the means which we gather from the ends themselves. About these is prudence, which applies universal principles to the particular conclusions of practical matters. Consequently it does not belong to prudence to appoint the end to moral virtues, but only to regulate the means.
Reply to Objection: 1. Natural reason known by the name of "synderesis" appoints the end to moral virtues, as stated above (I 79,12): but prudence does not do this for the reason given above.
2. This suffices for the Reply to the Second Objection.
3. The end concerns the moral virtues, not as though they appointed the end, but because they tend to the end which is appointed by natural reason. In this they are helped by prudence, which prepares the way for them, by disposing the means. Hence it follows that prudence is more excellent than the moral virtues, and moves them: yet "synderesis" moves prudence, just as the understanding of principles moves science.
Objection: 1. It would seem that it does not belong to prudence to find the mean in moral virtues. For the achievement of the mean is the end of moral virtues. But prudence does not appoint the end to moral virtues, as shown above (Article ). Therefore it does not find the mean in them.
2. Further, that which of itself has being, would seem to have no cause, but its very being is its cause, since a thing is said to have being by reason of its cause. Now "to follow the mean" belongs to moral virtue by reason of itself, as part of its definition, as shown above (Article , Objection ). Therefore prudence does not cause the mean in moral virtues.
3. Further, prudence works after the manner of reason. But moral virtue tends to the mean after the manner of nature, because, as Tully states (De Invent. Rhet. ii, 53), "virtue is a habit like a second nature in accord with reason." Therefore prudence does not appoint the mean to moral virtues.
On the contrary In the foregoing definition of moral virtue (Article , Objection ) it is stated that it "follows a mean appointed by reason . . . even as a wise man decides."
I answer that The proper end of each moral virtue consists precisely in conformity with right reason. For temperance intends that man should not stray from reason for the sake of his concupiscences; fortitude, that he should not stray from the right judgment of reason through fear or daring. Moreover this end is appointed to man according to natural reason, since natural reason dictates to each one that he should act according to reason.But it belongs to the ruling of prudence to decide in what manner and by what means man shall obtain the mean of reason in his deeds. For though the attainment of the mean is the end of a moral virtue, yet this mean is found by the right disposition of these things that are directed to the end.
Reply to Objection: 1. This suffices for the Reply to the First Objection.
2. Just as a natural agent makes form to be in matter, yet does not make that which is essential to the form to belong to it, so too, prudence appoints the mean in passions and operations, and yet does not make the searching of the mean to belong to virtue.
3. Moral virtue after the manner of nature intends to attain the mean. Since, however, the mean as such is not found in all matters after the same manner, it follows that the inclination of nature which ever works in the same manner, does not suffice for this purpose, and so the ruling of prudence is required.
Summa Th. II-II EN Qu.46