• The Slave of the Passions
• Reason Not the Source of Moral Distinctions
• The Moral Sense

The Slave of the Passions

There is a familiar image, with a long tradition among philosophers and the vulgar alike, of the combat of reason and the passions. Among philosophers, the image dates back at least to Plato, and it played a dominant role in Stoic thought. The image is familiar as well in Hume’s own time. Thus Pascal wrote of “the internal war of reason and the passions” (Pensées). Not only does the image of reason and passion’s combat play an important role in philosophical reflection on the determinants of the will and human action, but it plays a role as well in the thought of the vulgar. We are inclined to speak of a person who, in the throws of violent emotion, acts contrary to his interests as being “out of his senses”–the suggestion being that the operation of reason (involving, in this instance, the abilities to recognize what is in one’s best interest and to take relevant steps to promote, or at least not frustrate, that interest) has been disordered by the turbulence of felt emotion.

The image of reason and passion’s combat encourages a number of closely related claims:

• Reason and the passions can both determine the will.
• The passions can oppose reason’s determination of the will, and reason can oppose the passions’ determination of the will.
• Reason ought to determine the will.
• A person is only virtuous to the extent that his will is determined by reason.

Suppose that reason ought to determine the will and that a person is only virtuous to the extent that his will is determined by reason. Then, if the will is determined by passions that oppose the operation of reason, one acts not only unreasonably but viciously as well. This led many thinkers to lament reason’s enslavement to the passions.

Hume opposes this tradition, maintaining instead that (Treatise, 2.3.3.2):

• Reason alone can never determine the will.
• Reason alone can never oppose the passions’ determination of the will.

Instead, reason has a more limited role to play.

Reason’s Impotence

The two functions of reason that Hume officially recognizes are as follows (Treatise, 2.3.3.3):

• Reason may demonstrate certain truths based on the relations among our ideas (such as the truths of logic and mathematics).
• Reason may infer, or render probable, on the basis of experience, that the relations of cause and effect obtain between objects and events.

Hume argues that neither operation suffices to determine the will and motivate human action.

Of course demonstrative truths can have a practical application. Hume observes that mathematics is useful to mechanics (understood, here, as engineering). So understood, mechanics is “the art of regulating the motions of bodies to some design’d end or purpose” (Treatise, 2.3.3.2). Mathematics is useful to mechanics since by means of it we can determine the proportion of causal influence of one body over another. However, the effectiveness of demonstrative reasoning, its influence on the will, presupposes some end or purpose. Demonstrative reasoning may influence our actions—when, say, designing and building a bridge, but it does so only by directing our judgment concerning the propostion of causal influence. If a person did not have as an end the construction of a bridge, such causal judgments would have no influence on the will.

Similarly, causal truths can have a practical application. However, the effectiveness of causal reasoning, its influence on the will, presupposes some end or purpose:

It can never in the least concern us to know, that such objects are causes, and such others effects, if both the causes and effects be indifferent to us. Where the objects themselves do not affect us, their connexion can never give them any influence; and ‘tis plain, that as reason is nothing but the discovery of this connexion, it cannot be by its means that the objects are able to affect us. (Treatise, 2.3.3.3)

Since reason is limited to demonstrating truths about the relations of ideas and inferring truths about cause and effect, and these alone cannot determine the will, Hume concludes that reason alone can never determine the will.

Since reason alone can never determine the will, neither can it oppose the passions’ determination of the will. The passions’ determination of the will could only be opposed by a contrary determination, but, as Hume has shown, reason alone can never determine the will:

We speak not strictly and philosophically when we talk of the combat of passion and of reason. Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them. (Treatise, 2.3.3.4)

Hume is being deliberatively provocative here. To those who would lament reason’s enslavement to the passions, Hume retorts that not only is reason the slave of the passions, but it ought only to be. Notice that, in inverting the Stoic lament, Hume has also shifted the operative model of slavery. When, for example, Spinoza complains of our “bondage” to human passions, he has in mind the Egyptian enslavement of the Hebrews. When, however, Hume claims that reason is and ought only to be the slave of the passions, he has in mind the Roman enslavement of educated Greeks. Just as the influence of the Greek slaves over the Romans was limited to educating them, reason’s influence over the will is limited to “educating” the passions as to the presence of their objects and the causal means to their obtainment.

Two questions may be raised about Hume’s case:

1. How can Hume validly conclude that reason ought only to be the slave of the passions?
2. Even if Hume’s argument is valid, how convincing is it to someone who has a different conception of reason?

First, a question may be raised about the validity of Hume’s argument. How is Hume entitled to the claim that reason ought only to be the slave of the passions? From his premises, it may follow that reason is the slave of the passions—that reason can never determine the will nor oppose the passions’ determination of the will. But that reason ought only to be the slave of the passions is a further claim. I speculate that Hume is looking forward and backward here.

That reason to be the slave of the passions is the result of the self-vindicatory character of Hume’s sentimentalist explanation of morals. Recall that Hume wants to describe and explain the moral judgments we make, rather than prescribe certain moral judgments and justify them. However, Hume believes that once we recognize how the moral judgments that we make are properly explained in terms of internal sentiment, we will naturally approve of them and the mechanisms that give rise to them. As a corollary, once we recognize reason’s limited role in moral judgment we will naturally approve of reason’s limited role. It is this sense of approbation that is the basis of the claim that reason ought to be the slave of the passions. So Hume is look forward to the conclusion of Book III where he discusses the self-vindicatory character of his sentimentalist explanation of morals.

That reason ought only to be the slave of the passions is the result of Hume’s skepticism. Recall that Book I concludes on a note of a despair. What Hume despairs of is the possibility of reasonable metaphysical speculation about the supersensible nature of things—for example, about the nature of the necessary connection between cause and effect. Given the temptation to engage in unreasonable metaphysical speculation, it is only proper that reason be passion’s slave. For reason to pretend to any other office risks the kind of error that it is prone to when it engages in metaphysical speculation. So Hume is looking backward to the conclusion of Book I where he despairs of reason’s limits.

Second, a question may be raised about the persuasiveness of Hume’s argument. Even if valid, this line of argument may fail to convince, as Hume himself recognizes. The problem is that Hume’s conclusion follows from his restricted conception of reason. One might concede that if reason is limited to demonstrating truths about the relations of ideas or inferring causal truths, then reason alone can never determine the will and hence never oppose the passions’ determination of the will, and yet deny that reason’s function is so limited. Reason, as Hume understands it may never determine the will, but that is not yet to show that reason properly understood never determines the will.

The Master Argument

Hume recognizes this latter difficulty and provides an independent argument that the passions cannot be opposed by reason. Recall that passions are occurrent psychological episodes. They are simple impressions of reflection that arise under certain conditions and that prompt us to occasion further ideas and impressions and to act in certain ways. The passions are “original existences”, and so cannot represent anything. According to Hume, for a thing to have a representative quality it must be the “copy of another existence”, but the passions, being original existences are the copy of no other thing. Since the passions do not represent anything, they cannot contradict a truth discovered by reason.

Passions may not be opposed to reason by contradicting a truth discovered by reason, but perhaps the passions may be opposed to reason by certain judgments accompanying them contradicting a truth discovered by reason. Hume concedes that the passions may be contrary to reason, or unreasonable, in one of two ways:

1. When it is based on a false belief (e.g., when we are afraid of something because we falsely believe that it is dangerous).
2. When a choice of a means to the passion’s end is unreasonable, when the means do not have the expected effect.

But so conceding concedes little: “Where a passion is neither founded on false suppositions, nor chooses means insufficient for the end, the understanding can neither justify nor condemn it.” (Treatise, 2.3.3.6)

Hume underscores this point in an extraordinary passage:

‘Tis not contrary to reason to prefer the destruction of the whole world to the scratching of my finger. ‘Tis not contrary to reason for me to choose my total ruin, to prevent the least uneasiness of an Indian or person wholly unknown to me. ‘Tis as little contrary to reason to prefer even my own acknowledg’d lesser good to my greater, and have a more ardent affection for the former than the latter. A trivial good may, from certain circumstances, produce a desire superior to what arises from the greatest and most valuable enjoyment; nor is there anything more extraordinary in this, than in mechanics to see one pound weight raise up a hundred by the advantage of its situation. (Treatise, 2.3.3.6)

Again, Hume is being deliberatively provocative. It may no be contrary to reason to prefer the destruction of the whole world to the scratching of my finger in the strict and philosophical sense of reason, but there is another sense of reason familiar to the vulgar in which it would be utterly mad, insane, to prefer this. Hume invites this response, for, as we will see, it sets up his diagnosis of the mistake we make in speaking of the combat of reason and the passions.

Hume’s Diagnosis

Before we discuss Hume’s diagnosis, let’s first observe that, for Hume, preferences and value are independent of one another. A person may prefer what he judges to be a lesser good to a greater good (or a lesser pleasure to a greater pleasure—Hume regards pleasure and goodness as more or less equivalent). Hume’s metaphysics of mind commits him to this psychological claim. A person’s preferences are determined by his passions, and as these are original existences, they are independent of expectations of pleasure. So it is possible for a person to prefer an object that he expects to produce less pleasure than any other alternative. In this passage, all of Hume’s examples take this form. When a person prefers the destruction of the whole world to the scratching of his finger, he prefers something incompatible with his good. The same is true of preferring total ruin to prevent the least uneasiness in a person wholly unknown to oneself. Indeed the vulgar response that such preferences are utterly mad, insane, are due to their being contrary to the good and the sheer magnitude of this contrast.

When philosophers and the vulgar claim that reason can determine the will and oppose the passions’ determination of the will, they mistake the operation of certain calm passions for the operation of reason. Recall that the passions are either calm or violent. Calm passions “though they be real passions produce little emotion in the mind and are more known by their effects than by the immediate feeling of sensation” (Treatise, 2.3.3.8). In this way, they differ from violent passions which can be known by immediate feeling or sensation. Since reason itself exerts little sensible emotion, it is natural to mistake the operation of the calm passions, for the operation of reason.

What the vulgar call “passions” are really violent emotions that arise from any good or evil that excites that appetite. What the vulgar call “reason” are really emotions that operate more calmly and occasion no disorder. The calm passions include, among others, the general appetite to good and aversion to evil. Consider now the case of someone preferring the destruction of the whole world to the scratching of his finger. In this case, a strong violent emotion has overcome the weak general appetite for the good that operates more calmly and occasions no such disorder. This preference is not contrary to reason in the strict and philosophical sense. Rather, this preference occasions the distinctive pain of disapprobation from a more general point of view in characters where the calm passions operate more strongly. When the vulgar describe the preference for the destruction of the whole world as unreasonable, mad, insane, they are really giving confused expression to this sense of disapprobation.

Reason Not the Source of Moral Distinctions

Recall the elements of Hume’s metaphysics of mind. Whatever is present to the mind is a perception, and all the actions of the mind count as perceptions. Perceptions are either impressions or ideas depending on their relative force or vivacity. With these distinctions in place, Hume raises the question:

Whether ‘tis by means of our ideas or impressions we distinguish betwixt vice and virtue, and pronounce an action blameable or praise-worthy? (Treatise, 3.1.1.3)

Hume regards this as a more precise form of the question that divided moral rationalists (such as Malebranche, Clarke, and Cudworth) and moral sentimentalists (such as Shaftesbury and Hutcheson):

• Whether moral distinctions are determined by reason or internal sentiment?

According to moral rationalists, virtue is nothing but conformity to reason. As Hume interprets this doctrine, the rationalists are committed to the claim that the distinction between vice and virtue is determined by the relations among ideas and so demonstrable by reason. If Hume can show that the distinction between vice and virtue is not determined by means of our ideas, this will be sufficient grounds for rejecting the central claims of the moral rationalists, and so settle this debate in favor of moral sentimentalism.

One question to bear in mind: Is Hume’s more precise question an acceptable substitute for the question that drives the traditional pre-Humean debate between rationalists and sentimentalists? Does settling whether moral distinctions are drawn by means of ideas or impressions really settle the question of whether moral distinctions are determined by reason or internal sentiment?

Hume’s First Argument

Hume begins by observing that morals has an influence on the will and human action:

Philosophy is commonly divided into speculative and practical; and as morality is always comprehended under the latter division, ‘tis suppos’d to influence our passions and actions, and to go beyond the calm and indolent judgements of the understanding. And this is confirm’d by commone experience, which informs us, that men are often govern’d by their duties, and are deter’d from some actions by the opinions of injustice, and impell’d to others by that of obligation.

We have seen how in Treatise 2.3.3 Hume argues for the claim that reason alone can never determine the will. In Treatise 3.1.1, this important claim emerges as a central premise of Hume’s main argument against moral rationalism:

Since morals, therefore, have an influence on the actions and affections, it follows, that they cannot be deriv’d from reason; and that because reason alone, as we have already prov’d, can never have any such influence. Morals excite passions, and produce or prevent actions. Reason of itself is utterly impotent in this particular. The rules of morality, therefore, are not conclusions of our reason. (Treatise, 3.1.1.6)

More schematically, we can represent Hume’s argument as follows:

1. Reason alone cannot influence passions and actions.
2. Moral distinctions can influence passions and actions.
3. Therefore, moral distinctions are not discovered by reason.

Hume observes that the argument is valid, and regards the second premise as evident from cautious observation of human action, and so concludes that the only way to resist this argument is to deny the first premise, that reason alone cannot influence the passions and actions. He repeats the main argument of Treatise 2.3.3 (that passions are original existences, and so lack a representative quality, and so cannot be contrary to a truth discovered by reason), and supplements this with a battery of subsidiary arguments.

Hume’s Second Argument

Hume’s second argument against moral rationalism occurs in Treatise, 3.1.1.18–25. Moral rationalists maintain that morality is susceptible to demonstration. According to Hume, demonstrable truths are determined by the relations among ideas. Specially, among the philosophical relations there are four that are capable of demonstration:

• Resemblance
• Contrariety
• Degrees in quality
• Proportions in quantity and number

If moral distinctions really are demonstrable, then we must be able to discern them on the basis of one or more of these relations. Moral distinctions pertain exclusively to our actions, passions and volitions. However, the four demonstrable relations obtain not only among our actions, passions, and volitions, but among inanimate objects as well. So, the distinction between vice and virtue cannot be demonstrated on the basis of them.

The moral rationalist might concede that moral distinctions cannot be demonstrated on the basis of resemblance, contrariety, degrees in quality, or proportions of quantity and number. They might maintain, instead, that moral distinctions are demonstrable on the basis of some other relation. (Thus, one moral rationalist, Clarke, speaks of the relations of fittingness and unfittingness that virtuous and vicious actions bear to the circumstances in which they are performed.) If the moral rationalist is tempted to make this reply, Hume contends that he must explicitly specify the novel relations, and do so subject to two conditions:

1. First, the relations must obtain between perceptions in the mind and external objects.
2. Second, the relations, being demonstrable, are knowable a priori and cause everyone that knows them to act virtuously to some degree.

However, Hume doubts that these two conditions can be met.

First, the relations must obtain between perceptions in the mind and external objects. The relations could not obtain between perceptions alone or external objects alone. If what made for vice are relations that obtain between perceptions, it would be possible to be guilty of some vice independently of our external circumstances, but that’s implausible. If what made for vice are relations that obtain between external objects, then it would be possible for inanimate objects to be guilty of some vice, but that is implausible as well. So the relevant relations must obtain between perceptions in the mind and external objects. However, Hume contends that it is difficult to imagine a relation that obtains between perceptions and external objects that could not also obtain between perceptions alone, or external objects alone. So, it is implausible that the moral rationalist can successfully meet the first condition.

Second, the relations, being demonstrable, are knowable a priori and cause everyone that knows them to act virtuously to some degree:

…’tis not only suppos’d, that these relations, being eternal and immutable, are the same, when consider’d by every rational creature, but their effects are also suppos’d to be necessarily the same; and ‘tis concluded they have no less, or rather a greater, influence in directing the will on the deity, than in governing the rational and virtuous of our own species. (Treatise, 3.1.1.22)

However, “[t]hese two particulars are evidently distinct”:

‘Tis one thing to know virtue, and another to conform the will to it. In order, therefore, to prove, that the measures of right and wrong are eternal laws, obligatory on every rational mind, ‘tis not sufficient to show the relations upon which they are founded: We must also point out the connexion betwixt the relation and the will; and must prove that this connexion is so necessary, that in every well-dispos’d mind, it must take place and have its influence; tho’ the difference betwixt these minds be in other respects immense and infinite. (Treatise,3.1.1.22)

The problem is that there could be no proof of this necessary connection. The relations are demonstrable and so knowable independently of experience, but the causal effects of the relation could only be known on the basis of experience. According to Hume, then, the moral rationalists fail to successfully integrate their moral epistemology with an adequate explanation of moral motivation. So, it is implausible that the moral rationalist can successfully meet the second condition.

Hume’s Examples

Hume’s second argument is a piece of abstruse reasoning that may silence without convincing the moral rationalist. Hume recognizes this difficulty and addresses it by presenting the reader with concrete examples of vice. In reflecting on the moral judgments that these examples elicit, the reader can confirm for himself that moral distinctions are determined not by reason but by internal sentiment.

Hume discusses two kinds of example corresponding to the two operations of reason:

• Reason may demonstrate certain truths based on the relations among our ideas (such as the truths of logic and mathematics).
• Reason may infer, or render probable, on the basis of experience, that the relations of cause and effect obtain between objects and events.

In demonstrating a truth, reason compares ideas and determines the relations that obtain among them. If something is vicious and this is demonstrable by means of certain relations among ideas, then whenever these same relations obtain, something must be vicious. If something failed to be vicious though these same relations obtain, then vice could not consist in these relations among ideas. Hume tries to convince the reader of this by considering an uncontroversial example of vice:

Of all crimes that human creatures are capable of committing, the most horrid and unnatural is ingratitude, especially when it is committed against parents, and appears in the more flagrant instances of wounds and death. (Treatise, 3.1.1.24)

But the relations that obtain in cases of parricide may also obtain among inanimate objects in cases that manifestly involve no vice. Hume asks us to consider the example of a tree that produces a sapling that overtops it and destroys the parent tree. Observe that the tree and the sapling bear the same relations as parent and child in the case of parricide. However, whereas parricide is manifestly vicious, the sapling’s destroying the parent tree is manifestly not. So reason could not demonstrate parricide to be vicious on the basis of these relations. Hume’s second example of this kind is the uncontroversial vice of human incest. Observe that the relations that obtain in cases of human incest also obtain in cases of nonhuman incest. However, whereas human incest is manifestly vicious, nonhuman incest is manifestly not. So reason could not demonstrate human incest to be vicious on the basis of these relations.

Not only does reason demonstrate truths by comparing ideas and determining the relations that obtain among them, but reason may also infer matters of fact on the basis of experience. Hume asks us to consider the case of willful murder, and observe the matters of fact in that case:

Examine it in all lights, and see if you can find that matter of fact, or real existence, which may be called vice. In which-ever way you take it, you find only certain passions, motives, volitions, and thoughts. There is no other matter of fact in the case. The vice entirely escapes you, as long as you consider the object. (Treatise, 3.1.1.26)

If the vice of willful murder does not consist in any matter of fact and real existence discoverable by reason, then how is the manifest vice of willful murder determined by the human mind? If we cautiously observe what transpires as we engage in the imaginative exercise that Hume prescribes, we will discover that the vice is determined by an internal sentiment of disapprobation that is annexed to our idea of willful murder:

You never can find it, till you turn your reflection into your own breast, and find a sentiment of disapprobation, which arises in you, towards this action. here is a matter of fact; but ‘tis the object of felling, not of reason. It lies in yourself, not in the object. So that when you pronounce any action or character to be vicious, you mean nothing, but that from the constitution of your nature you have a feeling or sentiment of blame from the contemplation of it. (Treatise, 3.1.1.26)

Reason has two kinds of operations: (i) demonstrating truths on the basis of relations among ideas and (ii) inferring matters of fact on the basis of experience. Vice (and by implication virtue) could not be determined by relations among ideas nor by inferred matter of fact. Since these exhaust the operations of reason it follows that reason could not determine our judgments of virtue and vice.

Hume’s second kind of case—the case of willful murder—provides an independent reason for this conclusion. In imagining an instance of willful murder we can observe that our sense of its vice arises in the disapprobation we feel towards it. Not only does reflection on the case of willful murder help to establish Hume’s negative claim–that moral distinctions are not determined by reason, such reflection also establishes Hume’s positive claim—that moral distinctions are determined by internal sentiment. Not only does such reflection establish the falsity of moral rationalism, but such reflection also establishes the truth of moral sentimentalism.

The Moral Sense

Moral judgments are perceptions in the human mind. Perceptions are impressions or ideas but not both. So if moral judgments are not ideas, as Hume has argued, then they must be impressions. So Hume concludes that “[m]orality, therefore, is more properly felt than judg’d of” (Treatise, 3.1.2.1). Though rationalists are mistaken, their mistake is explicable. The sentiments by which morality is felt are often calm. Since calm sentiments have little sensible emotion they are apt to be confounded with ideas which they resemble in this respect.

If moral distinctions, particular judgments of virtue and vice, are impressions, what kind of impressions are they? According to Hume, virtue produces in the human mind an agreeable impression of pleasure, whereas vice produces in the human mind a disagreeable impression of pain:

virtue is distinguish’d by the pleasure, and vice by the pain, that any action sentiment or character gives us by the mere view and contemplation. (Treatise, 3.1.2.11)

First, notice that, for Hume, the objects of moral evaluation, the kinds of things that can be properly judged virtuous or vicious are actions, sentiments, and characters (understood as more or less stable configuration of passions). Later Hume will importantly qualify this: Actions may be judged virtuous or vicious but only derivatively—an action is virtuous or vicious only if its motive is virtuous or vicious. Second, notice that the pleasure and pain by which something is judged virtuous or vicious arises upon its contemplation. Later Hume will importantly qualify this as well: It is only pleasure or pain upon the general view or survey that distinguishes virtue and vice.

There is a potential difficulty with this sentimentalist proposal that parallel’s a difficulty that Hume raised for moral rationalism. In maintaining that virtue and vice consists in certain relations discernible by reason, rationalists are committed to the existence of virtue or vice wherever these relations obtain. The problem is that these relations obtain among inanimate objects, but only objects that can act and have sentiments and stable characters can be the objects of moral evaluation. But notice that we take pleasure and pain in inanimate objects, and so it can seem that sentimentalism faces the same difficulty that moral rationalism faced: Wrongly classifying inanimate objects as objects of moral evaluation.

However, Hume believes that sentimentalism has two replies unavailable to the rationalist:

• The particular pleasure or pain that we feel in judging of virtue and vice differs in kind from the pleasures or pains that we feel in response to things that are not the objects of moral evaluation.
• The particular pleasure or pain that we feel in judging of virtue and vice occasion the passions of pride and humility, love and hatred, but not all pains or pleasures we feel towards things that are not objects of moral evaluation can give rise to these passions.

First, the particular pleasure or pain that we feel in judging of virtue and vice differs in kind from the pleasures or pains that we feel in response to things that are not the objects of moral evaluation. The pleasure we take in music is not the same kind of pleasure that we take in a good bottle of wine. Just as we take distinctive pleasures in music and wine, Hume suggests that we take a distinctive pleasure in virtue. A virtuous action, sentiment, or character may occasion a particular pleasure, but this pleasure differs in kind from the particular pleasures occasioned by inanimate objects such as musical compositions and good bottles of wine.

Second, the particular pleasure or pain that we feel in judging of virtue and vice occasion the passions of pride and humility, love and hatred, but not all pains or pleasures we feel towards things that are not objects of moral evaluation can give rise to these passions. Recall that pride and humility and love and hatred are indirect passions that arise from the double relation of ideas and impressions. Whereas pride is an agreeable impression that takes the self as its object, love is an agreeable impression that takes another as its object. And whereas humility is a disagreeable impression that takes the self as its object, hate is a disagreeable impression that takes another as an object. If we classify indirect passions by whether they are agreeable or disagreeable and whether they take the self or the other as their object, we can taxonomize these passions as follows:

Virtue and vice involve agreeable and disagreeable impressions–they occasion a particular pleasure or pain. Moreover, the objects of moral evaluation are actions, sentiments, and characters, and these belong to either to oneself or another. Thus the moral pleasure that a person might take in his own character, through the double relations of ideas and impressions, occasions the passion of pride. Specifically, since it is the person’s character that is the object of moral pleasure, by the natural association of ideas, this will tend to occasion the person’s idea of himself. Since the moral pleasure resembles the pleasure of pride, by the natural association of impressions, this will tend to occasion the pleasure of pride. Later, Hume will classify virtues as whether they are useful or agreeable to self or to others. Correspondingly, Hume would classify vices as whether they are useless (or, rather, counterproductive) or disagreeable to self or to others. If we classify virtue and vice by whether they are agreeable or disagreeable and whether they take the self or the other as their object, we can taxonomize these on the model of the square of passions.

Not every inanimate object gives rise to these indirect passions. If the good bottle of wine that I take pleasure in is not proper to me and so does not occasion my idea of myself it will not give rise to pride. While not all things that fail to be the objects of moral evaluation give rise to the indirect passions, some do. So Hume’s second response to the difficulty of wrongly classifying inanimate objects as virtuous or vicious is incomplete. How do we distinguish the cases where the pleasures and pains that give rise to the indirect passions are moral approbation and disapprobation from those where they are not? Perhaps the answer to this question has to do with the nature of the circumstances that occasion the pleasure or pain–it is the pleasure and pain occasioned upon the general view or survey of an action, sentiment, or character that morality is judged of.

Since moral judgments just are particular pains or pleasures occasioned upon the general view or survey, to explain our moral judgments it suffices to explain the circumstances that occasion moral approbation and disapprobation. Recall that one advantage that Hume claims for his account of the passions is that they are governed by a few general principles rather than explaining each in terms of an original impulse. It is the way in which Hume can explain the multiplicity of observed phenomena with respect to the human passions in terms of a few general principles that makes it the paradigm of his new science of human nature. Hume also claims a similar advantage for his brand of moral sentimentalism:

For as the number of duties is, in a manner, infinite, ‘tis impossible that our original instincts shou’d extend to each of them, and from our very first infancy impress on the human mind all that multitude of precepts, which are contain’d in the compleatest system of ethics. (Treatise, 3.1.2.6)

Just as Hume explains the multiplicity of observed phenomena with respect to human passions in terms of a few general principles, Hume explains the multiplicity of observed phenomena with respect to human morality in terms of a few general principles. It is this further success of the new science of human nature that explains the upbeat character of the conclusion of Book III which contrasts so markedly with the note of despair upon which Book I concludes.