One of the positive recent trends in our culture has been a revival of interest in the virtues. For instance, William Bennett’s The Book of Virtues (1993) was a national bestseller. That book spawned another anthology, The Children’s Book of Virtues (1995), and a cartoon series on PBS called “Adventures from the Book of Virtues.” There is also a calendar called “The Garden of Virtues” and at least five hundred other books on virtue that one can purchase from Amazon.Com, including a parody of Bennett’s book by Tony Hendra with the self-contradictory title The Book of Bad Virtues (1994). Moreover, this trend in not limited to the culture-at-large. In Anglo-American philosophy, Peter Geach’s The Virtues (1977) and, more importantly, Alasdair MacIntyre’s After Virtue (1981) have sparked a renewed concern with “virtue-based” ethical theories that shows no sign of abating.
In light of this trend, it is worth re-asking some perennial questions about virtue. For instance, what is virtue? Are there different kinds of virtues? How are the various virtues connected? How are they acquired? And which virtues are most important? In what follows, I will consider how one medieval theologian, St. Thomas Aquinas (c. 1224-1274), answered these questions. Aquinas offered a remarkably systematic and thorough account of the virtues–one which is certainly unmatched by any contemporary philosopher. His answers are at least of historical interest, and to the extent that he had something insightful to say, he may help us to formulate our own answers to these questions.
To discover Aquinas’ account of virtue, the first (but by no means the only) place to turn is his Summa Theologiae, a three-volume handbook for “beginners” in theology. In the middle of the first part of the second volume (Prima Secundae Partis) Aquinas presented his treatise on virtue. A virtue, he argued, is a habit which perfects a power that a thing has.1 Among the powers that we have as human beings are the intellect and three appetitive powers: the will and two kinds of irrational appetites–one which accounts for our desires for various physical pleasures (called the ‘concupiscible appetite’) and another which accounts for emotions such as anger and fear (called the ‘irascible appetite’).2 These powers are capable of being determined in a variety of ways and towards a variety of ends. Some of those are good for us, others are not. For instance, we can have desires for foods that are healthy, and desires for foods that are unhealthy. Hence, we need good habits to dispose us to act in good ways for the sake of ends that are suitable and good for us, including our ultimate end and highest good–genuine happiness.3 These good habits are the virtues 4 and many of them are necessary in order to attain perfect happiness, which Aquinas argued earlier in the Summa Theologiae is the vision of God that the blessed experience in heaven.5 Following St. Augustine, Aquinas defined ‘virtue’ as a habit “by which we live righteously, of which no one can make bad use, which God works in us, without us.”6 As we will soon see, this definition does not apply to every kind of virtue that Aquinas discussed. Nevertheless, Aquinas used it because it captures the essence of what he thought are the most important kinds of virtues.
So what kinds of virtues did Aquinas distinguish? We can initially identify three main categories of virtue: intellectual, moral, and theological. Intellectual virtues, as the name suggests, perfect the intellectual powers of the human being. Following Aristotle,7 Aquinas distinguished the theoretical activities of the intellect from its practical activities. The intellect, in its theoretical activities, has as its object truth that cannot be otherwise.8 The intellect, in its practical activities, has as its object truth about things made or actions performed.9 Aquinas discussed three virtues that perfect the intellect in its theoretical activities: understanding, science, and wisdom. Briefly, the virtue of understanding perfects the intellect in its grasp of true principles; the different sciences (e.g., the science of geometry) perfect the intellect in its grasp of the truths which are derived from those principles; and wisdom perfects the intellect in its grasp of the highest causes, including the First and Supreme Cause (i.e., God).10 These three intellectual virtues are acquired, for the most part, by learning from others (e.g., by being taught geometry from a geometer).11 With respect to the intellect in its practical activities, one of the intellectual virtues that Aquinas mentioned is art. Aquinas defined ‘art’ as “right reason about certain works to be made.” Arts are skills, such as carpentry or medicine. These virtues dispose their possessor to produce works that are well done, e.g. a well-built house or a healed patient.12 Unlike the other intellectual virtues cited above, arts are acquired, for the most part, by practice.13
At this point we may remark that the category of intellectual virtue appears at first glance to be quite foreign to us. Setting aside the very different account of science that separates Aquinas from us, we do not typically think of intellectual prowess in, e.g., physics, as a virtue. Perhaps this is because we know all too well how knowledge in physics can be used for all kinds of morally questionable ends (such as the development of sophisticated weapons of mass destruction). Instead, we tend to restrict the term ‘virtue’ to habits that concern moral matters.
Yet there is less that separates us from Aquinas’ account than we may think. While these intellectual virtues confer an aptness in the intellect for grasping truth or for producing something well-made, Aquinas recognized that they do not guarantee that the possessor will use them appropriately. For instance, a skilled carpenter may deliberately make a defective product and a brilliant mathematician may deliberately make a mistake in a proof. As a result, Aquinas noted that the intellectual virtues are virtues only in an extended sense. Because they can be misused, intellectual virtues fall short of the full sense of virtue that is captured by Augustine’s definition.14
The second kind of virtue that Aquinas distinguished is moral virtue. The moral virtues perfect the appetitive powers of the soul.15 To cite three examples, the virtue of temperance (which concerns the pleasures that come from the table and the bedroom) is one of the virtues that perfects the concupiscible appetite. 16 The virtue of courage (which concerns the emotions of fear and confidence) is one of the virtues that perfects the irascible appetite.17 The virtue of justice (which concerns the interactions of people with each other) is one of the virtues that perfects the will.18 Following Aristotle, 19 Aquinas stressed that the moral virtues are unlike the intellectual virtues mentioned above in at least two significant ways. First, the moral virtues make their possessor a good person as such. In other words, a human being is a good person because that person is temperate, courageous, and just. The same cannot be said of a person who has artistic skill or scientific knowledge.20 Second, the moral virtues cannot be misused for evil purposes.21 Accordingly, because the moral virtues are habits “by which we live righteously” and “of which no one can make bad use,” they are more fully captured by Augustine’s definition than the intellectual virtues mentioned earlier.
There is, however, one intellectual virtue that is also a habit “by which we live righteously” and which cannot be misused. This is practical wisdom (prudentia), which Aquinas defined as “right reason of things to be done.”22 Practical wisdom involves good deliberation about the means to a good end, a correct judgment about what is to be done, and the execution of that good choice.23 Unlike wisdom, understanding, and science, practical wisdom perfects the intellect in its practical activities. Unlike the various arts, practical wisdom is concerned with human conduct rather than the making of products. Unlike all of the other intellectual virtues, practical wisdom cannot be misused for evil purposes because it is closely connected with the moral virtues. This interconnection of practical wisdom and moral virtue is frequently called ‘the Unity of the Virtues.’24
Aquinas’ argument for the unity of the virtues begins with the premise that the principle of human actions is the end. Since practical wisdom is right reason concerning human conduct, it requires that the person also be well disposed toward the appropriate ends of action. In order to be well-disposed with regard to the appropriate ends of action, the person must also have well-ordered appetites. Otherwise, the person might fail to recognize what the appropriate end is in a specific situation because of a disordered desire for some other, inappropriate end. Of course, the appetites are well-ordered by the moral virtues. So in order to have practical wisdom a person must also possess the moral virtues.25 The relationship also goes in the other direction–in order to possess the moral virtues, at least in their fullest sense, a person also needs to have practical wisdom. This is because in order to perform morally good deeds, it not only matters what a person does but how the person does it. The person must aim at a good end and also make a right choice about the means to that end. The moral virtues, by perfecting the appetites, insure that the person aims at a good end. But in order to secure these good ends one needs intelligence in selecting the right means, lest one stumble about in the attempt to do good.26 To insure that the person make the right choices about the means to a good end one needs practical wisdom.27 Therefore, the moral virtues and practical wisdom are interconnected so that a person cannot have the one without the other.
How are the moral virtues and practical wisdom acquired? Aquinas’ answer is a remarkable example of his attempt to synthesize philosophy and Christianity. One way to acquire these virtues is, as Aristotle recognized, by habituation and practice. For instance, one can become courageous by doing brave actions in the face of danger and thereby habituating oneself to feel fear and confidence in appropriate ways. Similarly, one can become temperate by acting temperately in the face of tempting pleasures, and just by acting justly in one’s dealings with others.28
But this is not the only means of acquiring these virtues. As a Catholic Christian, Aquinas also believed that God can transform human beings by pouring out His Grace upon them and infusing into them the moral virtues.29 These infused moral virtues, instead of being the result of human effort, are caused by God. Following Augustine, they are habits “which God works in us, without us.”30 Besides having different causes, the infused moral virtues differ from the acquired moral virtues in their respective ends and in their respective rules and measures. Concerning the former, the acquired moral virtues are directed toward an imperfect kind of happiness that can be achieved in this life. The infused moral virtues, on the other hand, are directed toward the perfect happiness that consists in the vision of God in heaven–a happiness which can be achieved only with God’s help. Concerning their respective rules and measures, the acquired moral virtues have as their rule and measure human reason, whereas the infused moral virtues have as their rule and measure Divine Law. Aquinas used the example of temperance to illustrate this difference. In the acquired virtue of temperance human reason dictates that the enjoyment of eating and drinking is proper so long as it does not harm the body or hinder the mind. In the infused virtue of temperance, on the other hand, Divine Law dictates that humans should “chastise their bodies and bring them into subjection” (I Cor. 9:27) by fasting and abstinence. Given the differences in their respective causes, ends, and measures, Aquinas concluded that the infused moral virtues and their acquired counterparts are altogether different species of virtues.31
This brings us to the third kind of virtue that Aquinas distinguished–theological virtue. While the moral virtues and practical wisdom are necessary for happiness, Aquinas denied that they are sufficient for the perfect happiness that consists in the vision of God in heaven. Since such happiness is beyond what humans can achieve on our own, we need the aid of God in order to achieve it. The theological virtues of faith, hope, and charity are three such aids.32 The virtue of faith, which perfects the intellect, concerns those truths about God that the intellect assents to “by means of a Divine light.”33 Aquinas defined ‘faith’ as “a habit of mind, whereby eternal life is begun in us, making the intellect assent to what is non-apparent.”34 The virtue of hope, which perfects the will, concerns the movement of the will toward perfect, eternal happiness as an end that is, by God’s help, attainable.35 The virtue of charity, which also perfects the will, concerns the love and friendship which unites the human being to God.36 The theological virtues, like the infused moral virtues, are habits that fully embody Augustine’s definition of virtue.37 Finally, just as the moral virtues and practical wisdom are interconnected, the infused moral virtues are interconnected with charity. Aquinas argued that when God infuses charity into the person, He infuses all of the other moral virtues as well.38
At this stage we may note that if the category of intellectual virtue seems foreign to us, the category of infused virtue is so a fortiori. I suspect that we usually think of virtues as habits that we acquire over time, often with much practice and a great deal of effort. Even if we agree with John Dewey that a habit can be formed on the basis of a single action,39 we might insist that the habit is nevertheless based on something that the possessor has done. Hence, we may agree with Thomas Hobbes that “the words in-poured virtue, in-blown virtue, are as absurd and insignificant as a round triangle.40
In Aquinas’ defense, three points may be made. First of all, if we are honest we will admit that there have been people who apparently have had life-changing religious conversions. Prior to their conversion, these people led decadent, self-indulgent, and even violent lives. After their conversion, they seem to reject completely their former lifestyle and now attempt to lead virtuous lives. These examples offer some confirmation of Aquinas’ thesis that some virtues are infused by God. Second, while the infused virtues are not caused by a person’s efforts, Aquinas recognized that when a person exercises these virtues, they are retained, deepened, and even increased.41 So, for example, each act of charity that a person does disposes that person to be more ready to act charitably in the future, and this eventually leads to an increase in the virtue of charity in that person.42 In this respect, the infused moral virtues resemble the acquired virtues. Third, a person may have difficulty exercising the infused moral virtues because of bad habits that were acquired in the past.43 Moreover, the failure to exercise the infused virtues weakens their power in one’s life, and one mortal sin destroys them altogether.44 Hence, the numerous Christians who struggle to act virtuously are not necessarily counter-examples to Aquinas’ thesis. Of course, none of these points prove that there are infused virtues.45 But they make this category more intelligible.
Given the mind-numbing number of virtues that Aquinas discussed, which did he think are the most important? Aquinas’ answer to this question starts from the following principle: for any two virtues, the more excellent virtue has the more excellent object.46 Hence, of all of the intellectual virtues, wisdom is the most important because its object–the First and Supreme Cause 47–is the most excellent object of knowledge.48 Of all of the moral virtues, justice is the most important because its object–the operations whereby people interact with each other–is the most excellent.49 Of the three kinds of virtues–intellectual, moral, and theological, the theological are the greatest because they have as their object God as He exists in Himself.50 Finally, of the three theological virtues, charity is the most important because, even though all of the theological virtues have God as their object, charity most closely unites the human being to God.51 Therefore, charity, “the mother and form of all the virtues,” is the most important of virtue of all.52
Having surveyed Aquinas’ extensive account of the virtues, what, if any, lessons can we draw from it? Let me suggest one main lesson. At the very least, Aquinas’ account reminds us what kinds of questions we need to ask about the virtues. For instance, what is the relation between virtue and happiness? Are at least some of the virtues necessary for happiness, as Aquinas thought? Are they sufficient for happiness (as the Stoics–but not Aquinas–thought)? Second, what kinds of virtues do we distinguish? Are all virtues moral virtues? Are there moral virtues that Aquinas’ extensive discussion overlooks, such as industry 53 or tolerance? Third, how are the various virtues related to each other? Are they merely related as items on a shopping list of ideal character traits? Or are the virtues systematically related to each other and, if so, how? Perhaps we can give better answers to these questions than Aquinas gave. But if we are to construct an account that rivals his in its breadth and depth, we have a lot of work to do.
2. The appetites are irrational because they are also found in non-human animals. See, e.g., S.T. I, qq. 79-82; I-II q. 56, a. 4.
3. S.T. I-II, q. 49, a. 4.
4. See S.T. I-II, q. 55, a. 3; Commentary on the Nicomachean Ethics, Book II, Lectures V-VI.
5. S.T. I-II, q. 4, a. 4. Notice that, on Aquinas’ account, perfect happiness, while presupposing the rectitude of the will that comes from moral virtue, is not morally virtuous activity. Nor is it mere contemplative activity, as Aristotle argued in Nicomachean Ethics X, 7-8. These are imperfect forms of happiness that are attainable in this life by human effort. Perfect happiness, on the other hand, is the “vision of the Divine Essence.” This is both unattainable in this life and beyond our capacity to secure for ourselves by our own effort. See S.T. I-II, q. 2, a. 8; q. 3, a. 8; q. 5, a. 5; Summa Contra Gentiles, Book III, Chapters xxxvii-xl, xlvii-xlviii.
6. St. Augustine, On Free Will, II 19; S.T. I-II, q. 55, a. 4.
7. Aristotle, De Anima III 7; Nicomachean Ethics VI 1-2.
8. S.T. I-II, q. 56, a. 3; q. 57, aa. 1-2. See Aristotle, Nicomachean Ethics VI 1 (1139 a 6-15) and Aquinas’ Commentary on the Nicomachean Ethics, Book VI, Lecture I, ##1115-1123.
9. S.T. I-II, q. 57, aa. 3-4. See Aristotle, Nicomachean Ethics VI 2 (1139 a 20- b 14) and Aquinas’ Commentary on the Nicomachean Ethics, Book VI, Lecture II, ##1130-1132.
10. S.T. I-II, q. 57, a. 2. See Aristotle, Nicomachean Ethics VI 3, 6-7; Metaphysics I 1 and Aquinas’ Commentary on the Nicomachean Ethics, Book VI, Lectures III, V-VI.
11. Commentary on the Nicomachean Ethics, Book II, Lecture 1, #246. See Aristotle, Nicomachean Ethics II 1 (1103 a 15).
12. S.T. I-II, q. 57, a. 3. See Aristotle, Nicomachean Ethics VI 4 and Aquinas’ Commentary on the Nicomachean Ethics, Book VI, Lecture III, ##1150-1160 .
13. Commentary on the Nicomachean Ethics, Book II, Lecture 1, #252. See Aristotle, Nicomachean Ethics II 1 (1103 a 32-33).
14. S.T. I-II, q. 56, a. 3; q. 57, aa. 1, 3 and Aquinas’ Commentary on the Nicomachean Ethics, Book VI, Lecture IV, ##1172-1174.
15. S.T. I-II, q. 50, aa. 3, 5; q. 56, aa. 4, 6.
16. S.T. I-II, q. 60, a. 4; cf. II-II, qq. 141, 143 and Commentary on the Nicomachean Ethics, Book III, Lecture XIX, #595-596. See Aristotle, Nicomachean Ethics III 10-12. Among the secondary virtues that are connected to temperance and that pertain to the concupiscible appetite are abstinence, sobriety, chastity, and virginity; cf. S.T. II-II, qq. 146, 149, 151-152.
17. S.T. I-II, q. 60, a. 4; cf. II-II, qq. 123-124, 128. See Aristotle, Nicomachean Ethics III 6-9. Among the secondary virtues that are connected to courage and that pertain to the irascible appetite are magnificence, magnanimity, patience, and perseverance; cf. S.T. II-II, qq. 128, 129, 134, 136, 137.
18. S.T. I-II, q. 60, aa. 2-3; cf. II-II, qq. 58, 61, 80. See Aristotle, Nicomachean Ethics V. Among the secondary virtues that are connected to justice are religion, piety, friendliness, and generosity; cf. S.T. II-II, qq. 81, 101, 114, 117.
19. See Aristotle, Nicomachean Ethics II 6 (1106 a 15-24).
20. S.T. I-II, q. 56, a. 3; Disputed Questions on Virtue, a. 7. The argument is roughly as follows. Aquinas starts from the premise that the good under its proper formality is the subject of the appetitive part alone. Consequently, those habits which either reside in or depend upon the appetitive part (specifically, the will) are formally ordained to the good. The habits that reside in the other powers (i.e., intellect, concupiscible and irascible appetites) depend upon the will in so far as the will moves these other powers. It moves the sense appetites in so far as it is superior to them, and so a person does not act on these appetites (at least not voluntarily) unless the will consents (see S.T. I, q. 81, a. 3). Although absolutely speaking the will is inferior to the intellect, it nevertheless is able to move the intellect, for a person considers something with his intellect because he wills to do so (see S.T. I, q. 82, a. 4). Therefore, if a person actually do something well (homo actu bene agat), this is because he has a good will. Therefore, the virtue that makes a person to actually do something well, must either be in the will itself or in some power as moved by the will. This is either moral virtue or a virtue that perfects the intellect in so far as it is subordinate to the will (e.g., faith and practical wisdom).
21.Once again, the reason is because these virtues perfect the appetitive parts of the soul (or the intellect in so far as it is moved by the will). Aquinas seems to assume that the only possible reason why a virtue would be misused is because of a disordered appetite (i.e., either a disordered will or disordered sense appetites). See Commentary on the Nicomachean Ethics, Book VI, Lecture IV, #1173.
22. S.T. I-II, q. 57, a. 4. See Aristotle, Nicomachean Ethics, VI 5 (1140 b 5) and Aquinas’ Commentary on the Nicomachean Ethics, Book VI, Lecture IV, #1166.
23. S.T. I-II, q. 57, aa. 4-6; also see II-II, qq. 47-49, 51. See Aristotle, Nicomachean Ethics VI 9-11 and Aquinas’ Commentary on the Nicomachean Ethics, Book VI, Lectures VIII-IX.
24. The doctrine of the unity of the virtues may have been universally held among the ancient and medieval philosophers. See Julia Annas, The Morality of Happiness (Oxford; Oxford University Press, 1993), pp. 73-84.
25. S.T. I-II, q. 57, a. 4; cf. q. 58, a. 5. See Aristotle, Nicomachean Ethics, VI 5, 12 and Aquinas’ Commentary on the Nicomachean Ethics, Book VI, Lecture X, ##1268-1269.
26. See Commentary on the Nicomachean Ethics, Book VI, Lecture XI, ##1279-1280.
27. S.T. I-II, q. 58, a. 4. The full argument is as follows. Moral virtue is, as Aristotle argued, a habit of choosing well (Nicomachean Ethics II 6, 1106 b 36). In order that the choice be good, the intention must be directed to a good end, and the means selected must be good. Moral virtue, by perfecting the appetites, insures that the end is good. Practical wisdom insures that the means selected are good because it involves good deliberation, correct judgment, and the execution of the appropriate choice. Hence, to act rightly in the right sort of way, both moral virtue and practical wisdom are required. See Aristotle, Nicomachean Ethics VI 13 and Aquinas’ Commentary on the Nicomachean Ethics, Book VI, Lecture ##1275-1288.
28. S.T. I-II, q. 63, a. 2; Disputed Questions on Virtue, a. 9; Commentary on the Nicomachean Ethics, Book II, Lecture 1, ##252-253. See Aristotle, Nicomachean Ethics II 1 (1103 a 32- b 25). Like Aristotle, Aquinas was fairly silent about how practical wisdom is acquired. Presumably, it is also acquired by habituation and experience, and it develops simultaneous with the moral virtues.
29. S.T. I-II, q. 63, a. 3; Disputed Questions on Virtue, a. 10.
30. St. Augustine, On Free Will, II 19; S.T. I-II, q. 55, a. 4.
31. S.T. I-II, q. 63, a. 4.
32. S.T. I-II, q. 62, a. 1. These virtues are called ‘theological’ because (1) their object is God, (2) they are infused in humans by God, and (3) they are made known to humans only by Divine Revelation in the Holy Scriptures.
33. S.T. I-II, q. 62, a. 3.
34. S.T. II-II, q. 4, aa. 1, 2. Aquinas argued that this definition captures what the author of the Letter to the Hebrews meant when he wrote, “Faith is the substance of things to be hoped for, the evidence of things that appear not” (Heb. 9:1).
35. S.T. I-II, q. 62, a. 3; II-II, q. 17, aa. 1-2.
36. S.T. I-II, q. 62, a. 3; II-II, q. 23, a. 1.
37. St. Augustine, On Free Will, II 19; S.T. I-II, q. 55, a. 4; q. 65, a. 2.
38. S.T. I-II, q. 65, aa. 2-3. Aquinas argues whenever a thing has a principle for specific works it also has the means necessary for their execution. Charity, in as much as it directs the person to the last end, is the principle of all of the good works that are referable to that end. Hence, charity requires all of the infused moral virtues to perform each different kind of good work that is directed toward perfect happiness.
39. See, e.g., Logic: The Theory of Inquiry (Chicago: Holt, Rinehart and Winston, 1939), pp. 31-32.
40. Leviathan, Part I, Chapter 4.
41. S.T. II-II, q. 24, a. 4. Aquinas’ argument focuses on charity, but I see no reason why it would not apply to the other infused virtues as well.
42. S.T. II-II, q. 24, a. 6.
43. S.T. I-II, q. 65, a. 3, ad. 2.
44. S.T. II-II, q. 24, aa.10-12.
45. As a theological thesis, the existence of infused virtues would have to be proven from principles that are ultimately accepted on faith. Cf. S.T. I, q. 1, a.2.
46. Occasionally Aquinas also argues that the greater virtue has the greater subject matter and the greater subject. So practical wisdom, justice, courage and temperance are the four cardinal virtues that are superior to the other moral virtues because their subject matters are more important than those of the secondary moral virtues. For instance, courage is greater than the secondary virtues connected to it (e.g., magnanimity) because its subject matter–the dangers of death–is greater (S.T. I-II, q. 61, aa. 2-3). Of the four cardinal virtues, practical wisdom is the greatest because its subject–the intellect–is greater than the subjects of the other cardinal virtues (S.T. I-II, q. 66, a. 3, ad 3).
47. That is, the object of wisdom is God as He is understood by means of human reason unaided by revelation. For Aquinas, the paradigm of such knowledge is found in Aristotle’s Metaphysics.
48. S.T. I-II, q. 66, a. 5.
49. S.T. I-II, q. 66, a. 4. Another reason why justice is greater than the other moral virtues is because it perfects the will, which is a greater appetitive power than the two irrational appetites. See Aristotle, Nicomachean Ethics V 1 (1129 b 25- 1130 a 12).
50. Since wisdom also has God as its object, one might wonder why the theological virtues (e.g., faith) are superior to wisdom. Aquinas’ answer is that the knowledge of God that we have by faith is more sublime than the wisdom about God that one can acquire by means of human reason unaided by revelation. See, e.g., Summa Contra Gentiles, Book III, Chapter xl.
51. S.T. I-II, q. 66, a. 6; II-II, q. 23, a. 6. Aquinas explained that whereas faith and hope imply a certain distance between the human being and God, the love of charity is of that which is already possessed.
52. S.T. II-II, q. 23, a. 8.
53. For an alternative list of virtues, see, e.g., Benjamin Franklin,
The Autobiography of Ben Franklin, Chapter 8.