In Hume's philosophical corpus, there are only ten passages that explicitly mention Aristotle, and only two of these refer to Aristotle's ethics. It is nevertheless clear that Hume had the ancients in general, and Aristotle in particular, in his sights at various junctures in his moral philosophy. Hume's Treatise discussion of “greatness of mind,” for instance, deliberately appropriates elements of both Aristotelian megalopsychia and Ciceronian magnitudo animi.

My concern in this essay is with Hume's appropriation of one of the most central elements of Aristotle's ethics – the distinction between “true virtue” and “mere continence.” Hume well understood this distinction but he also held that while there can be morally significant differences between someone who acts in the face of temptation and someone who is not conflicted in acting as he ought, the latter state is not always morally preferable to the former. Hume's reception of the old Aristotelian saw, we might say half smiling, was mixed.

To see why Hume so received this doctrine, I begin with this problem confronting Aristotelians: the contrast between true virtue and mere continence seems to leave one unable to make sense of a significant arena of our everyday moral responses. Contemporary Aristotelians are aware of this difficulty. Unfortunately, some of the best-known attempts to make room for the common moral responses at issue are worse than unhelpful. To begin with, they fail to accommodate the very phenomena they were designed to accommodate. Furthermore, the proposed solutions reveal their authors to be committed not only to a problematic conception of good character, but also to a troublesome conception of the difference between character traits and other practical dispositions that are sometimes distinguished from character traits – pathologies, disorders, proficiencies, talents, abilities, and personality quirks.

When the Italian humanist Francis Petrarch (1304–1374) defended himself against certain followers of Aristotle in his On His Own Ignorance and That of Many Others, he contrasted the approach to ethics taken by ancient Latin writers (Cicero, Seneca, Horace) with that of Aristotle in his Nicomachean Ethics (henceforth Ethics). It was an unequal battle: although Aristotle offers a good definition of what virtue is, Petrarch says, “his lesson lacks the words that sting and set afire and urge toward love of virtue and hatred of vice or, at any rate, does not have enough of such power. He who looks for that will find it in our Latin writers […].” Petrarch went on to explain that “our Latin writers […] stamp and drive deep into the heart the sharpest and most ardent stings of speech, by which the lazy are startled, the ailing are kindled, and the sleepy aroused, the sick healed, and the prostrate raised, and those who stick to the ground lifted up to the highest thoughts and to honest desire.” Since virtues “must be not merely known but loved,” the “true moral philosophers” are

In other words, Petrarch was saying, a philosophical and abstract definition of virtue or treatment of ethics is not enough: it must be accompanied by powerful language which urges the reader on in his pursuit of what is good. The implication was that this dimension was lacking in Aristotle's work. He may have been good at identifying and defining virtue, but the Ethics does not actually fill the reader with desire for it.

iv.1.1 We must examine justice and injustice, the kinds of actions that they are concerned with, the kind of mean point that justice is, and what it is a mean between. iv.1.2 Let our investigation use the same method as our preceding discussions.

iv.1.3 Now we see that everyone wishes to speak of justice as the kind of state that makes people inclined to do just deeds, to act justly, and to wish for what is just. Injustice is spoken of in the same manner, as that which makes people do injustice and wish for what is unjust. So let this be laid down as our initial outline too.

iv.1.4 There is a disanalogy between kinds of knowledge and capacities on the one hand, and states on the other. It seems that with a capacity or a kind of knowledge, the same one encompasses opposites, whereas any state that is opposite to another does not encompass opposites. For example, opposite outcomes do not result from health, only healthy ones, since we say that someone walks healthily whenever he walks as a healthy person would.

i.1.1 The poet who declared his opinion at the god’s site in Delos, inscribing it on the gateway of the Temple of Leto, distinguished the good, the fine and the pleasant as not all belonging to the same thing. He wrote: ‘Finest is what is most just, best is being healthy, most pleasant of all is to attain what one desires.’ We should not agree with him. For happiness, being finest and best, is the most pleasant of all things.

i.1.2 There are many points of interest concerning each kind of object and nature that create difficulty and need examining. Some of these pertain only to our knowing, others pertain to the acquisition of the object and to actions as well. i.1.3 Regarding those that involve only theoretical philosophy, we must state, when the right opportunity presents itself, whatever is appropriate to the field of enquiry. i.1.4 First, however, we must examine what living well consists in and how it is to be achieved.

Do all who acquire this label get to be happy by nature, as with tallness and shortness and differences in skin colour? Or is it through learning, happiness being a kind of knowledge? Or is it through some sort of practice? After all, people acquire many qualities not by nature or learning but by habituation; bad qualities if they are badly habituated, good qualities if they are well habituated. Or is it in none of these ways, i.1.5 but in one or other of the following: by the influence of some divine force, like those people possessed by nymphs or gods, as if inspired; or by luck, since many people claim that happiness and good fortune are the same thing? i.1.6 Evidently it comes to be present in people in all or some or one of these ways. For pretty much everything one gets can be attributed to these sources, since actions based on thought can be grouped together with those that result from knowledge.

The opening line of the Nicomachean Ethics introduces one of Aristotle’s best-known contributions to philosophy: ‘Every skill and every enquiry, and similarly every action and rational choice, is thought to aim at some good.’ This captures an inspiring and optimistic view of human nature, as does the equally famous opening of the Metaphysics, ‘All human beings by nature desire to know.’ Striving for the good and striving for knowledge are two of the key elements of Aristotle’s profound view of what is significant in the life of human beings. Less well known is the emphasis Aristotle places on the role of pleasure, healthy pleasure at least, in a good human life. And that view is featured in the opening sentences of his other major work on happiness and successful human living, the Eudemian Ethics. Aristotle criticizes the wise old poet Theognis for driving a wedge between what is pleasant and what is fine and good. ‘We should not agree with him. For happiness, being finest and best, is the most pleasant of all things.’

Aristotle’s unexpected focus on the pleasantness of the happy life is just one of the many significant, though often subtle, differences between Aristotle’s two authoritative books on ethics, distinguished since antiquity by the epithets ‘Nicomachean’ and ‘Eudemian’. These labels allude to his son Nicomachus and his famous student Eudemus of Rhodes. The reason why these two labels were chosen to designate Aristotle’s two works on ethics, Aristotle’s motivation for writing two different books on the topic, and the relationships between them are all issues mired in uncertainty and controversy. Each of these questions demands proper discussion, but at the outset we want to draw attention to some important basic facts about Aristotle’s Eudemian Ethics which make it eminently worth reading and indeed studying with as much care and attention as we routinely devote to the Nicomachean Ethics. First and foremost, it is important to recognize that the Eudemian Ethics is a complete treatment of happiness and the good human life, and in our view it was probably the first one Aristotle wrote. And if this is so, then it clearly demands our attention as a discussion of fundamental human values written by one of the great philosophers of the western tradition. But the nature of the work has been controversial, and so we should begin with a bit of background.

v.1.1 Since we have in fact already said that one must choose the mean, and not the excess or the deficiency, and since the mean is as correct reasoning says it is, let us make some distinctions here. In all the states discussed, just as in other matters, there is a target which the rational person looks to as he intensifies and relaxes, and there is a defining limit for the mean states, which we say lie between the excess and the deficiency, being in accordance with correct reasoning. v.1.2 Now this claim is true, but not at all clear. For in other concerns governed by knowledge it is true to say that one ought to labour and to ease off neither too much nor too little, but moderately and as correct reasoning indicates. But assuming that this is all one has, one would be none the wiser about how to treat the body if one were to say ‘what medicine and the medical practitioner dictates’. v.1.3 That is why when it comes to the states of the soul this claim, though true, is not enough, but there must also be distinctions about what the correct reasoning is and what its defining limit is.

v.1.4 When we distinguished the virtues of the soul we said that some were virtues of character and some virtues of thought. We have dealt with the virtues of character; let us now discuss the others, after first saying something about the soul. v.1.5 Earlier, then, it was said that there are two parts of the soul, one rational and the other non-rational. Now we should make a similar division with regard to the rational part, and let it be postulated that there are two rational parts, one by which we contemplate the kinds of existing things whose starting points cannot be otherwise and the other by which we contemplate things which admit of being otherwise. For corresponding to objects which differ in kind there are also parts of the soul, different in kind, which naturally correspond to each kind of object, if it really is the case that they have knowledge in accordance with a kind of similarity and suitability. v.1.6 Let one of these be called ‘scientific’ and the other ‘calculative’; deliberation and calculation are the same and no one deliberates about things which do not admit of being otherwise. Consequently, the calculative is a single, distinct part of the rational part. v.1.7 One should, then, get a grasp of what the best state of each of these rational parts is. For this is the virtue of each and the virtue is relative to its proper function.

viii.1.1 One might wonder whether it is possible to use each thing both for its natural purpose and otherwise – and this either in itself or, on the other hand, incidentally. For example, an eye; one might use it to see or also otherwise, to mis-see, by displacing it so that one object appears as two. Both of these use it as an eye, because it is an eye, but there is another, incidental use; for instance, if it were possible to sell it or to eat it. viii.1.2 So too for knowledge. One can use it genuinely and also to make a mistake; for instance, when one voluntarily writes incorrectly one uses one’s knowledge as ignorance, as when one twists one’s hand out of place; and dancing girls sometimes use their feet as hands and vice versa.

viii.1.3 If all virtues are forms of knowledge it would also be possible to use justice as injustice and one would then commit injustice by performing unjust acts on the basis of justice, as one can also perform ignorant acts on the basis of knowledge. But if this is impossible, it is obvious that the virtues would not be forms of knowledge. And if it is not possible to be ignorant on the basis of knowledge, but only to make a mistake and to perform the same actions as are done on the basis of ignorance, then certainly one will also not do anything based on justice as though it were based on injustice. But again, if wisdom is knowledge and something that is true, then it too will behave in the same way. It would then be possible to act foolishly on the basis of wisdom and to make the same mistakes as a fool would make. But if the use of each thing as what it is were simple, then in acting that way people would also be acting wisely.

vii.1.1 We must investigate friendship, what it is and what qualities it has; who is a friend, and whether friendship is a term used univocally or in many ways; and if it is used in many ways, how many; and also how one should interact with a friend and what the justice associated with friendship is. This investigation is no less important than the investigation of what is fine and choiceworthy in character traits. vii.1.2 For it is a particular function of the political art to produce friendship; and people say that virtue is useful for this reason, since those who are treated unjustly by one another cannot be friends to each other. vii.1.3 Moreover, we all say that justice and injustice have a particular bearing on friends; and we think that the same man is both good and a friend, and that friendship is a state connected to character. And if one wants to bring it about that people not commit injustice it is a good idea to make them friends to one another, since true friends do not commit injustice. vii.1.4 But it is also the case that if they are just they will not commit injustice. Consequently justice and friendship are either the same thing or nearly so.

vii.1.5 In addition, we hold that a friend is one of the greatest goods and that friendlessness and isolation are most dreadful, since our whole life and our voluntary associations are bound up with friends. For we pass our days either with members of our household, or with our relatives, or with our companions, or with our children, parents or our wife. vii.1.6 And the private justice that deals with our friends is the only one that is up to us, while that which involves other relationships is subject to legislation and is not up to us.