Summa Th. II-II EN Qu.47 a.8

Whether command is the chief act of prudence?

Objection: 1. It would seem that command is not the chief act of prudence. For command regards the good to be ensued. Now Augustine (De Trin. xiv, 9) states that it is an act of prudence "to avoid ambushes." Therefore command is not the chief act of prudence.
2. Further, the Philosopher says (Ethic. vi, 5) that "the prudent man takes good counsel." Now "to take counsel" and "to command" seem to be different acts, as appears from what has been said above (I-II 57,6). Therefore command is not the chief act of prudence.
3. Further, it seems to belong to the will to command and to rule, since the will has the end for its object, and moves the other powers of the soul. Now prudence is not in the will, but in the reason. Therefore command is not an act of prudence.

On the contrary The Philosopher says (Ethic. vi, 10) that "prudence commands."
I answer that Prudence is "right reason applied to action," as stated above (Article [2]). Hence that which is the chief act of reason in regard to action must needs be the chief act of prudence. Now there are three such acts. The first is "to take counsel," which belongs to discovery, for counsel is an act of inquiry, as stated above (I-II 14,1). The second act is "to judge of what one has discovered," and this is an act of the speculative reason. But the practical reason, which is directed to action, goes further, and its third act is "to command," which act consists in applying to action the things counselled and judged. And since this act approaches nearer to the end of the practical reason, it follows that it is the chief act of the practical reason, and consequently of prudence.In confirmation of this we find that the perfection of art consists in judging and not in commanding: wherefore he who sins voluntarily against his craft is reputed a better craftsman than he who does so involuntarily, because the former seems to do so from right judgment, and the latter from a defective judgment. On the other hand it is the reverse in prudence, as stated in Ethic. vi, 5, for it is more imprudent to sin voluntarily, since this is to be lacking in the chief act of prudence, viz. command, than to sin involuntarily.

Reply to Objection: 1. The act of command extends both to the ensuing of good and to the avoidance of evil. Nevertheless Augustine ascribes "the avoidance of ambushes" to prudence, not as its chief act, but as an act of prudence that does not continue in heaven.
2. Good counsel is required in order that the good things discovered may be applied to action: wherefore command belongs to prudence which takes good counsel.
3. Simply to move belongs to the will: but command denotes motion together with a kind of ordering, wherefore it is an act of the reason, as stated above (I-II 17,1).

Whether solicitude belongs to prudence?

Objection: 1. It would seem that solicitude does not belong to prudence. For solicitude implies disquiet, wherefore Isidore says (Etym. x) that "a solicitous man is a restless man." Now motion belongs chiefly to the appetitive power: wherefore solicitude does also. But prudence is not in the appetitive power, but in the reason, as stated above (Article [1]). Therefore solicitude does not belong to prudence.
2. Further, the certainty of truth seems opposed to solicitude, wherefore it is related (1S 9,20) that Samuel said to Saul: "As for the asses which were lost three days ago, be not solicitous, because they are found." Now the certainty of truth belongs to prudence, since it is an intellectual virtue. Therefore solicitude is in opposition to prudence rather than belonging to it.
3. Further, the Philosopher says (Ethic. iv, 3) the "magnanimous man is slow and leisurely." Now slowness is contrary to solicitude. Since then prudence is not opposed to magnanimity, for "good is not opposed to good," as stated in the Predicaments (viii) it would seem that solicitude does not belong to prudence.

On the contrary It is written (1P 4,7): "Be prudent . . . and watch in prayers." But watchfulness is the same as solicitude. Therefore solicitude belongs to prudence.
I answer that According to Isidore (Etym. x), a man is said to be solicitous through being shrewd [solers] and alert [citus], in so far as a man through a certain shrewdness of mind is on the alert to do whatever has to be done. Now this belongs to prudence, whose chief act is a command about what has been already counselled and judged in matters of action. Hence the Philosopher says (Ethic. vi, 9) that "one should be quick in carrying out the counsel taken, but slow in taking counsel." Hence it is that solicitude belongs properly to prudence, and for this reason Augustine says (De Morib. Eccl. xxiv) that "prudence keeps most careful watch and ward, lest by degrees we be deceived unawares by evil counsel."

Reply to Objection: 1. Movement belongs to the appetitive power as to the principle of movement, in accordance however, with the direction and command of reason, wherein solicitude consists.
2. According to the Philosopher (Ethic. i, 3), "equal certainty should not be sought in all things, but in each matter according to its proper mode." And since the matter of prudence is the contingent singulars about which are human actions, the certainty of prudence cannot be so great as to be devoid of all solicitude.
3. The magnanimous man is said to be "slow and leisurely" not because he is solicitous about nothing, but because he is not over-solicitous about many things, and is trustful in matters where he ought to have trust, and is not over-solicitous about them: for over-much fear and distrust are the cause of over-solicitude, since fear makes us take counsel, as stated above (I-II 44,2) when we were treating of the passion of fear.

Whether solicitude belongs to prudence?

Objection: 1. It would seem that prudence does not extend to the governing of many, but only to the government of oneself. For the Philosopher says (Ethic. v, 1) that virtue directed to the common good is justice. But prudence differs from justice. Therefore prudence is not directed to the common good.
2. Further, he seems to be prudent, who seeks and does good for himself. Now those who seek the common good often neglect their own. Therefore they are not prudent.
3. Further, prudence is specifically distinct from temperance and fortitude. But temperance and fortitude seem to be related only to a man's own good. Therefore the same applies to prudence.

On the contrary Our Lord said (Mt 24,45): "Who, thinkest thou, is a faithful and prudent [Douay: 'wise'] servant whom his lord hath appointed over his family?"
I answer that According to the Philosopher (Ethic. vi, 8) some have held that prudence does not extend to the common good, but only to the good of the individual, and this because they thought that man is not bound to seek other than his own good. But this opinion is opposed to charity, which "seeketh not her own" (1Co 13,5): wherefore the Apostle says of himself (1Co 10,33): "Not seeking that which is profitable to myself, but to many, that they may be saved." Moreover it is contrary to right reason, which judges the common good to be better than the good of the individual.Accordingly, since it belongs to prudence rightly to counsel, judge, and command concerning the means of obtaining a due end, it is evident that prudence regards not only the private good of the individual, but also the common good of the multitude.

Reply to Objection: 1. The Philosopher is speaking there of moral virtue. Now just as every moral virtue that is directed to the common good is called "legal" justice, so the prudence that is directed to the common good is called "political" prudence, for the latter stands in the same relation to legal justice, as prudence simply so called to moral virtue.
2. He that seeks the good of the many, seeks in consequence his own good, for two reasons. First, because the individual good is impossible without the common good of the family, state, or kingdom. Hence Valerius Maximus says [*Fact. et Dict. Memor. iv, 6] of the ancient Romans that "they would rather be poor in a rich empire than rich in a poor empire." Secondly, because, since man is a part of the home and state, he must needs consider what is good for him by being prudent about the good of the many. For the good disposition of parts depends on their relation to the whole; thus Augustine says (Confess. iii, 8) that "any part which does not harmonize with its whole, is offensive."
3. Even temperance and fortitude can be directed to the common good, hence there are precepts of law concerning them as stated in Ethic. v, 1: more so, however, prudence and justice, since these belong to the rational faculty which directly regards the universal, just as the sensitive part regards singulars.

Whether prudence about one's own good is specifically the same as that which extends to the common good?

Objection: 1. It seems that prudence about one's own good is the same specifically as that which extends to the common good. For the Philosopher says (Ethic. vi, 8) that "political prudence, and prudence are the same habit, yet their essence is not the same."
2. Further, the Philosopher says (Polit. iii, 2) that "virtue is the same in a good man and in a good ruler." Now political prudence is chiefly in the ruler, in whom it is architectonic, as it were. Since then prudence is a virtue of a good man, it seems that prudence and political prudence are the same habit.
3. Further, a habit is not diversified in species or essence by things which are subordinate to one another. But the particular good, which belongs to prudence simply so called, is subordinate to the common good, which belongs to political prudence. Therefore prudence and political prudence differ neither specifically nor essentially.

On the contrary "Political prudence," which is directed to the common good of the state, "domestic economy" which is of such things as relate to the common good of the household or family, and "monastic economy" which is concerned with things affecting the good of one person, are all distinct sciences. Therefore in like manner there are different kinds of prudence, corresponding to the above differences of matter.
I answer that As stated above (Article [5]; Question [54], Article [2], ad 1), the species of habits differ according to the difference of object considered in its formal aspect. Now the formal aspect of all things directed to the end, is taken from the end itself, as shown above (FS, Prolog.; I-II 102,1), wherefore the species of habits differ by their relation to different ends. Again the individual good, the good of the family, and the good of the city and kingdom are different ends. Wherefore there must needs be different species of prudence corresponding to these different ends, so that one is "prudence" simply so called, which is directed to one's own good; another, "domestic prudence" which is directed to the common good of the home; and a third, "political prudence," which is directed to the common good of the state or kingdom.

Reply to Objection: 1. The Philosopher means, not that political prudence is substantially the same habit as any kind of prudence, but that it is the same as the prudence which is directed to the common good. This is called "prudence" in respect of the common notion of prudence, i.e. as being right reason applied to action, while it is called "political," as being directed to the common good.
2. As the Philosopher declares (Polit. iii, 2), "it belongs to a good man to be able to rule well and to obey well," wherefore the virtue of a good man includes also that of a good ruler. Yet the virtue of the ruler and of the subject differs specifically, even as the virtue of a man and of a woman, as stated by the same authority (Polit. iii, 2).
3. Even different ends, one of which is subordinate to the other, diversify the species of a habit, thus for instance, habits directed to riding, soldiering, and civic life, differ specifically although their ends are subordinate to one another. In like manner, though the good of the individual is subordinate to the good of the many, that does not prevent this difference from making the habits differ specifically; but it follows that the habit which is directed to the last end is above the other habits and commands them.

Whether prudence is in subjects, or only in their rulers?

Objection: 1. It would seem that prudence is not in subjects but only in their rulers. For the Philosopher says (Polit. iii, 2) that "prudence alone is the virtue proper to a ruler, while other virtues are common to subjects and rulers, and the prudence of the subject is not a virtue but a true opinion."
2. Further, it is stated in Polit. i, 5 that "a slave is not competent to take counsel." But prudence makes a man take good counsel (Ethic. vi, 5). Therefore prudence is not befitting slaves or subjects.
3. Further, prudence exercises command, as stated above (Article [8]). But command is not in the competency of slaves or subjects but only of rulers. Therefore prudence is not in subjects but only in rulers.

On the contrary The Philosopher says (Ethic. vi, 8) that there are two kinds of political prudence, one of which is "legislative" and belongs to rulers, while the other "retains the common name political," and is about "individual actions." Now it belongs also to subjects to perform these individual actions. Therefore prudence is not only in rulers but also in subjects.
I answer that Prudence is in the reason. Now ruling and governing belong properly to the reason; and therefore it is proper to a man to reason and be prudent in so far as he has a share in ruling and governing. But it is evident that the subject as subject, and the slave as slave, are not competent to rule and govern, but rather to be ruled and governed. Therefore prudence is not the virtue of a slave as slave, nor of a subject as subject.Since, however, every man, for as much as he is rational, has a share in ruling according to the judgment of reason, he is proportionately competent to have prudence. Wherefore it is manifest that prudence is in the ruler "after the manner of a mastercraft" (Ethic. vi, 8), but in the subjects, "after the manner of a handicraft."

Reply to Objection: 1. The saying of the Philosopher is to be understood strictly, namely, that prudence is not the virtue of a subject as such.
2. A slave is not capable of taking counsel, in so far as he is a slave (for thus he is the instrument of his master), but he does take counsel in so far as he is a rational animal.
3. By prudence a man commands not only others, but also himself, in so far as the reason is said to command the lower powers.

Whether prudence can be in sinners?

Objection: 1. It would seem that there can be prudence in sinners. For our Lord said (Lc 16,8): "The children of this world are more prudent [Douay: 'wiser'] in their generation than the children of light." Now the children of this world are sinners. Therefore there be prudence in sinners.
2. Further, faith is a more excellent virtue than prudence. But there can be faith in sinners. Therefore there can be prudence also.
3. Further, according to Ethic. vi, 7, "we say that to be of good counsel is the work of prudent man especially." Now many sinners can take good counsel. Therefore sinners can have prudence.

On the contrary The Philosopher declares (Ethic. vi, 12) that "it is impossible for a man be prudent unless he be good." Now no inner is a good man. Therefore no sinner is prudent.
I answer that Prudence is threefold. There is a false prudence, which takes its name from its likeness to true prudence. For since a prudent man is one who disposes well of the things that have to be done for a good end, whoever disposes well of such things as are fitting for an evil end, has false prudence, in far as that which he takes for an end, is good, not in truth but in appearance. Thus man is called "a good robber," and in this way may speak of "a prudent robber," by way of similarity, because he devises fitting ways of committing robbery. This is the prudence of which the Apostle says (Rm 8,6): "The prudence [Douay: 'wisdom'] of the flesh is death," because, to wit, it places its ultimate end in the pleasures of the flesh.The second prudence is indeed true prudence, because it devises fitting ways of obtaining a good end; and yet it is imperfect, from a twofold source. First, because the good which it takes for an end, is not the common end of all human life, but of some particular affair; thus when a man devises fitting ways of conducting business or of sailing a ship, he is called a prudent businessman, or a prudent sailor; secondly, because he fails in the chief act of prudence, as when a man takes counsel aright, and forms a good judgment, even about things concerning life as a whole, but fails to make an effective command.The third prudence is both true and perfect, for it takes counsel, judges and commands aright in respect of the good end of man's whole life: and this alone is prudence simply so-called, and cannot be in sinners, whereas the first prudence is in sinners alone, while imperfect prudence is common to good and wicked men, especially that which is imperfect through being directed to a particular end, since that which is imperfect on account of a failing in the chief act, is only in the wicked.

Reply to Objection: 1. This saying of our Lord is to be understood of the first prudence, wherefore it is not said that they are prudent absolutely, but that they are prudent in "their generation."
2. The nature of faith consists not in conformity with the appetite for certain right actions, but in knowledge alone. On the other hand prudence implies a relation to a right appetite. First because its principles are the ends in matters of action; and of such ends one forms a right estimate through the habits of moral virtue, which rectify the appetite: wherefore without the moral virtues there is no prudence, as shown above (I-II 58,5); secondly because prudence commands right actions, which does not happen unless the appetite be right. Wherefore though faith on account of its object is more excellent than prudence, yet prudence, by its very nature, is more opposed to sin, which arises from a disorder of the appetite.
3. Sinners can take good counsel for an evil end, or for some particular good, but they do not perfectly take good counsel for the end of their whole life, since they do not carry that counsel into effect. Hence they lack prudence which is directed to the good only; and yet in them, according to the Philosopher (Ethic. vi, 12) there is "cleverness," [*(deinotike)] i.e. natural diligence which may be directed to both good and evil; or "cunning," [*(panourgia)] which is directed only to evil, and which we have stated above, to be "false prudence" or "prudence of the flesh."

Whether prudence is in all who have grace?

Objection: 1. It would seem that prudence is not in all who have grace. Prudence requires diligence, that one may foresee aright what has to be done. But many who have grace have not this diligence. Therefore not all who have grace have prudence.
2. Further, a prudent man is one who takes good counsel, as stated above (Article [8], Objection [2]; Article [13], Objection [3]). Yet many have grace who do not take good counsel, and need to be guided by the counsel of others. Therefore not all who have grace, have prudence
3. Further, the Philosopher says (Topic. iii, 2) that "young people are not obviously prudent." Yet many young people have grace. Therefore prudence is not to be found in all who have grace.

On the contrary No man has grace unless he be virtuous. Now no man can be virtuous without prudence, for Gregory says (Moral. ii, 46) that "the other virtues cannot be virtues at all unless they effect prudently what they desire to accomplish." Therefore all who have grace have prudence.
I answer that The virtues must needs be connected together, so that whoever has one has all, as stated above (I-II 65,1). Now whoever has grace has charity, so that he must needs have all the other virtues, and hence, since prudence is a virtue, as shown above (Article [4]), he must, of necessity, have prudence also.

Reply to Objection: 1. Diligence is twofold: one is merely sufficient with regard to things necessary for salvation; and such diligence is given to all who have grace, whom "His unction teacheth of all things" (1Jn 2,27). There is also another diligence which is more than sufficient, whereby a man is able to make provision both for himself and for others, not only in matters necessary for salvation, but also in all things relating to human life; and such diligence as this is not in all who have grace.
2. Those who require to be guided by the counsel of others, are able, if they have grace, to take counsel for themselves in this point at least, that they require the counsel of others and can discern good from evil counsel.
3. Acquired prudence is caused by the exercise of acts, wherefore "its acquisition demands experience and time" (Ethic. ii, 1), hence it cannot be in the young, neither in habit nor in act. On the other hand gratuitous prudence is caused by divine infusion. Wherefore, in children who have been baptized but have not come to the use of reason, there is prudence as to habit but not as to act, even as in idiots; whereas in those who have come to the use of reason, it is also as to act, with regard to things necessary for salvation. This by practice merits increase, until it becomes perfect, even as the other virtues. Hence the Apostle says (He 5,14) that "strong meat is for the perfect, for them who by custom have their senses exercised to the discerning of good and evil."

Whether prudence is in us by nature?

Objection: 1. It would seem that prudence is in us by nature. The Philosopher says that things connected with prudence "seem to be natural," namely "synesis, gnome" [*(synesis) and (gnome), Cf. I-II 57,6] and the like, but not those which are connected with speculative wisdom. Now things belonging to the same genus have the same kind of origin. Therefore prudence also is in us from nature.
2. Further, the changes of age are according to nature. Now prudence results from age, according to Jb 12,12: "In the ancient is wisdom, and in length of days prudence." Therefore prudence is natural.
3. Further, prudence is more consistent with human nature than with that of dumb animals. Now there are instances of a certain natural prudence in dumb animals, according to the Philosopher (De Hist. Anim. viii, 1). Therefore prudence is natural.

On the contrary The Philosopher says (Ethic. ii, 1) that "intellectual virtue is both originated and fostered by teaching; it therefore demands experience and time." Now prudence is an intellectual virtue, as stated above (Article [4]). Therefore prudence is in us, not by nature, but by teaching and experience.
I answer that As shown above (Article [3]), prudence includes knowledge both of universals, and of the singular matters of action to which prudence applies the universal principles. Accordingly, as regards the knowledge of universals, the same is to be said of prudence as of speculative science, because the primary universal principles of either are known naturally, as shown above (Article [6]): except that the common principles of prudence are more connatural to man; for as the Philosopher remarks (Ethic. x, 7) "the life which is according to the speculative reason is better than that which is according to man": whereas the secondary universal principles, whether of the speculative or of the practical reason, are not inherited from nature, but are acquired by discovery through experience, or through teaching.On the other hand, as regards the knowledge of particulars which are the matter of action, we must make a further distinction, because this matter of action is either an end or the means to an end. Now the right ends of human life are fixed; wherefore there can be a natural inclination in respect of these ends; thus it has been stated above (I-II 51,1; I-II 63,1) that some, from a natural inclination, have certain virtues whereby they are inclined to right ends; and consequently they also have naturally a right judgment about such like ends.But the means to the end, in human concerns, far from being fixed, are of manifold variety according to the variety of persons and affairs. Wherefore since the inclination of nature is ever to something fixed, the knowledge of those means cannot be in man naturally, although, by reason of his natural disposition, one man has a greater aptitude than another in discerning them, just as it happens with regard to the conclusions of speculative sciences. Since then prudence is not about the ends, but about the means, as stated above (Article [6]; I-II 57,5), it follows that prudence is not from nature.

Reply to Objection: 1. The Philosopher is speaking there of things relating to prudence, in so far as they are directed to ends. Wherefore he had said before (Ethic. vi, 5,11) that "they are the principles of the (ou heneka)" [*Literally, 'for the sake of which' (are the means)], namely, the end; and so he does not mention (euboulia) among them, because it takes counsel about the means.
2. Prudence is rather in the old, not only because their natural disposition calms the movement of the sensitive passions, but also because of their long experience.
3. Even in dumb animals there are fixed ways of obtaining an end, wherefore we observe that all the animals of a same species act in like manner. But this is impossible in man, on account of his reason, which takes cognizance of universals, and consequently extends to an infinity of singulars.

Whether prudence can be lost through forgetfulness?

Objection: 1. It would seem that prudence can be lost through forgetfulness. For since science is about necessary things, it is more certain than prudence which is about contingent matters of action. But science is lost by forgetfulness. Much more therefore is prudence.
2. Further, as the Philosopher says (Ethic. ii, 3) "the same things, but by a contrary process, engender and corrupt virtue." Now the engendering of prudence requires experience which is made up "of many memories," as he states at the beginning of his Metaphysics (i, 1). Therefore since forgetfulness is contrary to memory, it seems that prudence can be lost through forgetfulness.
3. Further, there is no prudence without knowledge of universals. But knowledge of universals can be lost through forgetfulness. Therefore prudence can also.

On the contrary The Philosopher says (Ethic. vi, 5) that "forgetfulness is possible to art but not to prudence."
I answer that Forgetfulness regards knowledge only, wherefore one can forget art and science, so as to lose them altogether, because they belong to the reason. But prudence consists not in knowledge alone, but also in an act of the appetite, because as stated above (Article [8]), its principal act is one of command, whereby a man applies the knowledge he has, to the purpose of appetition and operation. Hence prudence is not taken away directly by forgetfulness, but rather is corrupted by the passions. For the Philosopher says (Ethic. vi, 5) that "pleasure and sorrow pervert the estimate of prudence": wherefore it is written (Da 13,56): "Beauty hath deceived thee, and lust hath subverted thy heart," and (Ex 23,8): "Neither shalt thou take bribes which blind even the prudent [Douay: 'wise']."Nevertheless forgetfulness may hinder prudence, in so far as the latter's command depends on knowledge which may be forgotten.

Reply to Objection: 1. Science is in the reason only: hence the comparison fails, as stated above [*Cf. I-II 53,1].
2. The experience required by prudence results not from memory alone, but also from the practice of commanding aright.
3. Prudence consists chiefly, not in the knowledge of universals, but in applying them to action, as stated above (Article [3]). Wherefore forgetting the knowledge of universals does not destroy the principal part of prudence, but hinders it somewhat, as stated above.


We must now consider the parts of prudence, under which head there are four points of inquiry:

(1) Which are the parts of prudence?

(2) Of its integral parts;

(3) Of its subjective parts;

(4) Of its potential parts.

Whether three parts of prudence are fittingly assigned?

Objection: 1. It would seem that the parts of prudence are assigned unfittingly. Tully (De Invent. Rhet. ii, 53) assigns three parts of prudence, namely, "memory," "understanding" and "foresight." Macrobius (In Somn. Scip. i) following the opinion of Plotinus ascribes to prudence six parts, namely, "reasoning," "understanding," "circumspection," "foresight," "docility" and "caution." Aristotle says (Ethic. vi, 9,10,11) that "good counsel," "synesis" and "gnome" belong to prudence. Again under the head of prudence he mentions "conjecture," "shrewdness," "sense" and "understanding." And another Greek philosopher [*Andronicus; Cf. Question [80], Objection [4]] says that ten things are connected with prudence, namely, "good counsel," "shrewdness," "foresight," "regnative [*Regnativa]," "military," "political" and "domestic prudence," "dialectics," "rhetoric" and "physics." Therefore it seems that one or the other enumeration is either excessive or deficient.
2. Further, prudence is specifically distinct from science. But politics, economics, logic, rhetoric, physics are sciences. Therefore they are not parts of prudence.
3. Further, the parts do not exceed the whole. Now the intellective memory or intelligence, reason, sense and docility, belong not only to prudence but also to all the cognitive habits. Therefore they should not be set down as parts of prudence.
4. Further, just as counselling, judging and commanding are acts of the practical reason, so also is using, as stated above (I-II 16,1). Therefore, just as "eubulia" which refers to counsel, is connected with prudence, and "synesis" and "gnome" which refer to judgment, so also ought something to have been assigned corresponding to use.
5. Further, solicitude pertains to prudence, as stated above (Question [47], Article [9]). Therefore solicitude also should have been mentioned among the parts of prudence.

I answer that Parts are of three kinds, namely, "integral," as wall, roof, and foundations are parts of a house; "subjective," as ox and lion are parts of animal; and "potential," as the nutritive and sensitive powers are parts of the soul. Accordingly, parts can be assigned to a virtue in three ways. First, in likeness to integral parts, so that the things which need to concur for the perfect act of a virtue, are called the parts of that virtue. In this way, out of all the things mentioned above, eight may be taken as parts of prudence, namely, the six assigned by Macrobius; with the addition of a seventh, viz. "memory" mentioned by Tully; and (eustochia) or "shrewdness" mentioned by Aristotle. For the "sense" of prudence is also called "understanding": wherefore the Philosopher says (Ethic. vi, 11): "Of such things one needs to have the sense, and this is understanding." Of these eight, five belong to prudence as a cognitive virtue, namely, "memory," "reasoning," "understanding," "docility" and "shrewdness": while the three others belong thereto, as commanding and applying knowledge to action, namely, "foresight," "circumspection" and "caution." The reason of their difference is seen from the fact that three things may be observed in reference to knowledge. In the first place, knowledge itself, which, if it be of the past, is called "memory," if of the present, whether contingent or necessary, is called "understanding" or "intelligence." Secondly, the acquiring of knowledge, which is caused either by teaching, to which pertains "docility," or by "discovery," and to this belongs to (eustochia), i.e. "a happy conjecture," of which "shrewdness" is a part, which is a "quick conjecture of the middle term," as stated in Poster. i, 9. Thirdly, the use of knowledge, in as much as we proceed from things known to knowledge or judgment of other things, and this belongs to "reasoning." And the reason, in order to command aright, requires to have three conditions. First, to order that which is befitting the end, and this belongs to "foresight"; secondly, to attend to the circumstances of the matter in hand, and this belongs to "circumspection"; thirdly, to avoid obstacles, and this belongs to "caution."The subjective parts of a virtue are its various species. In this way the parts of prudence, if we take them properly, are the prudence whereby a man rules himself, and the prudence whereby a man governs a multitude, which differ specifically as stated above (Question [47], Article [11]). Again, the prudence whereby a multitude is governed, is divided into various species according to the various kinds of multitude. There is the multitude which is united together for some particular purpose; thus an army is gathered together to fight, and the prudence that governs this is called "military." There is also the multitude that is united together for the whole of life; such is the multitude of a home or family, and this is ruled by "domestic prudence": and such again is the multitude of a city or kingdom, the ruling principle of which is "regnative prudence" in the ruler, and "political prudence," simply so called, in the subjects.If, however, prudence be taken in a wide sense, as including also speculative knowledge, as stated above (Question [47], Article [2], ad 2) then its parts include "dialectics," "rhetoric" and "physics," according to three methods of prudence in the sciences. The first of these is the attaining of science by demonstration, which belongs to "physics" (if physics be understood to comprise all demonstrative sciences). The second method is to arrive at an opinion through probable premises, and this belongs to "dialectics." The third method is to employ conjectures in order to induce a certain suspicion, or to persuade somewhat, and this belongs to "rhetoric." It may be said, however, that these three belong also to prudence properly so called, since it argues sometimes from necessary premises, sometimes from probabilities, and sometimes from conjectures.The potential parts of a virtue are the virtues connected with it, which are directed to certain secondary acts or matters, not having, as it were, the whole power of the principal virtue. In this way the parts of prudence are "good counsel," which concerns counsel, "synesis," which concerns judgment in matters of ordinary occurrence, and "gnome," which concerns judgment in matters of exception to the law: while "prudence" is about the chief act, viz. that of commanding.

Reply to Objection: 1. The various enumerations differ, either because different kinds of parts are assigned, or because that which is mentioned in one enumeration includes several mentioned in another enumeration. Thus Tully includes "caution" and "circumspection" under "foresight," and "reasoning," "docility" and "shrewdness" under "understanding."
2. Here domestic and civic prudence are not to be taken as sciences, but as kinds of prudence. As to the other three, the reply may be gathered from what has been said.
3. All these things are reckoned parts of prudence, not by taking them altogether, but in so far as they are connected with things pertaining to prudence.
4. Right command and right use always go together, because the reason's command is followed by obedience on the part of the lower powers, which pertain to use.
5. Solicitude is included under foresight.

Summa Th. II-II EN Qu.47 a.8