1. The Typical Scenario

I begin by sketching a common way to think of the relation between our passions, reason, and our behavior. Passions often upset us, overtake us, and prompt us to do things that we later regret. If we only had paused to think over the situation, we might have acted in a cool-headed and reasonable way instead. We talk about crimes of passion, like killing a beloved in a fit of jealousy or anger, and we do so because we regard passions as motives, often motives to bad behavior (but, of course, not always). This picture is intuitively plausible and it seems to assume that reason can be at odds with passion, can direct a person's actions and push her toward opposite objectives. Also, on a popular view of value, to act from reason is to act prudently or virtuously or for the sake of morality; while to act on passion is often to be imprudent, reckless, vicious, or at minimum less than fully virtuous. Unruly passions can get the best of us.

There is a long tradition of support for this sort of view, but my interest is in what the seventeenth- and eighteenth-century intellectuals, at least up until David Hume's publication of his Treatise of Human Nature (1739–40), thought about passion, reason, and action. In Books 2 and 3 of his famous Treatise, Hume takes on the traditional view and argues that the view makes no sense of human psychology, given what passions and reason are, or how they function. Among his main theses is the thesis that reason, without a passion, simply cannot be a motive to action. Surprisingly, a survey of theories on the passions and action in the seventeenth- and eighteenth-century reveals that few, if any, of the thinkers explicitly held the view that reason in any of its functions motivates action without a passion. Yet, they did hold the general view I just sketched above. The details concerning how passion and action are practically opposed to one another matters a great deal here, and so I look closely at some of the theories of the passions prevalent in the early modern period and then return to Hume later. It's clear that he and his adversaries are operating with different conceptions of what a passion is. However, I think there remains a mystery about with whom he disagrees when it comes to the capacity of reason.Footnote ¹

In the dominant Ancient-Medieval view, the passions were passive powers, or capacities to be affected by objects, in the way that the senses are.Footnote ² The early moderns, on the other hand, pointed to the activity of the passions and tried to address the relation between mind and body in many of their accounts of our psychology. One of the salient features of the passions was their influence on action, and so many of the modern thinkers insisted that the passions could be useful when controlled, but harmful or misleading when not.Footnote ³ Thus, a prevailing theme in the work of these philosophers was the governance of the passions. Eschewing the view that the passions could moderate themselves, they asked whether reason could control the passions, or whether an external authority was necessary.

2. Seventeenth-Century Theories of Passion and Reason

The connection of passions to action and their relation to reason is a theme evident in discussions early in the seventeenth century. In 1621, French theologian, Nicolas Coeffeteau, in A Table of Humane Passions, defines a passion as ‘a motion of the sensitive appetite’ caused by apprehending good or evil and followed by a bodily movement ‘contrary to the Lawes of Nature’. Because the rational part of the soul does not initiate change in the body, Coeffeteau holds that the passions reside in a different part of the soul.Footnote ⁴ In his Treatise of the Passions and Faculties of the Soule of Man (first published 1640), Edward Reynolds (vice chancellor of Oxford University and later bishop of Norwich) portrays the passions as ‘natural, perfective’ motions that humans receive from their creator for the advancement of their natures. He supposes that humans have an infused desire for the good, and that the passions enhance human nature by inclining us to good objects or by producing an aversion to noxious ones.Footnote ⁵ The ‘dignity’ of the passions lies in their ministering to reason in the execution of duties, which are to the benefit of our nature.Footnote ⁶ The will is a blind faculty on its own, but the understanding serves as its adviser, either to furnish it with an end upon which to ‘fasten,’ or to direct it to the means to that end, all in accord with the rules of ‘right reason’.Footnote ⁷ It looks as though, on Reynolds's view, reason can give us an end or tell us the means to a proper end, with passion providing an impetus to act on reason's direction.

French philosopher Jean-François Senault (The Use of the Passions, 1641) agrees that the passions can be beneficial and suggests that the Ancient Stoics were wrong to argue that the best life is one in which we relinquish our passions and practice insensitivity to the vicissitudes of the world. Senault thought that the passions are useful and that any can become a virtue, since all involve natural inclinations to good and away from evil.Footnote ⁸ It is dangerous, however, for one passion to moderate another by opposition (e.g. opposing hope to fear), ‘fortifying one enemy to destroy another’. Moderation instead requires reason, which is ‘king over Passions … their government is one of her chief Employments’.Footnote ⁹ Yet, reason is not sufficient without the aid of God's grace.Footnote ¹⁰

Other seventeenth-century philosophers were preoccupied with the role of physiology in the production of the passions and their effects. This is a theme that Descartes and Malebranche share. According to Descartes, passions are generated by our decisions to bring certain objects to mind, by the temperament of the body, and by ‘impressions haphazardly encountered in the brain,’ as when one feels depressed and is unable to say why. But most of the passions are produced by an object's being characterized as good or bad for us.Footnote ¹¹ (The exceptions are wonder, esteem and scorn, pride and humility, veneration and disdain.) Descartes observes that the chief effect of the passions is ‘that they incite and dispose their soul to will the things for which they prepare their body, so that the sensation of fear incites it to will to flee, that of boldness to do battle, and so on for the rest’.Footnote ¹² On his view, the passions can oppose reason, since such an opposition is really between passionate representations and non-passionate representations. For instance, I have the confused thought of a dental procedure as an evil, along with the volition to avoid it, constituting the passion of fear. That thought is pitted against the thought that I will be much better off by having the procedure performed immediately. So, on Descartes's conception, passions are representations of states of affairs as good or evil and involve volitions or motives toward beneficial objects and away from the harmful.

According to Malebranche, God has implanted in our minds inclinations naturally directed toward the Good in general, God's end. Various particular proclivities, such as curiosity, self-love (manifested variously as love of well-being, love of grandeur, the desire for knowledge, the desire to appear learned, inclination for riches, love of pleasure and things that make us happy) and friendship for others, are aspects of the general instinct to the Good.Footnote ¹³ Yet, one's will can derail them. The mind has the power to direct its natural inclinations by ordering the understanding to represent to it particular objects. ‘A person represents some honor to himself as a good that he might hope for; the will immediately wills this good; that is, the impression toward indeterminate and universal good that the mind is continuously receiving conveys it toward this honor’.Footnote ¹⁴ We also, however, have the freedom to suspend our love of this honor and pursue other goods when we understand that it is not the universal good. Like many of the philosophers preceding him, Malebranche portrays the passions with the power to distort our perception of good, and his theory offers a physiological explanation of how passions infect our reactions toward related things.

3. Early Eighteenth-Century Intellectuals

At the beginning of the 1700's, English theologians William Ayloffe, Musidoris Burghope, and Francis Bragge perpetuated the thesis that persons’ passions, left on their own, have a malignant and destructive effect. In The Government of the Passions according to the Rules of Reason and Religion (1700), Ayloffe repeats several themes from Senault: that it is unsafe to use one passion to ‘repel’ another;Footnote ¹⁵ that only reason with God's grace can restrain the passions, since reason is ‘obnubulated’ (darkened or obscured) by original sin;Footnote ¹⁶ and that the passions are the seeds of virtue.Footnote ¹⁷ My chief interest here is in the way in which the passions receive reason's guidance. Ayloffe says that the soul is slave to the senses, which are deceitful and produce erroneous ‘knowledge’, under whose direction the passions become ‘irregular’.Footnote ¹⁸ ‘[O]ur Passions are only criminal because they are deceiv'd’. Thus, the passions are not in themselves depraved, but reason must show them their objects ‘in genuine Colours’, and it serves to remove the objects that tend to promote rebellion and upheaval.Footnote ¹⁹ Burghope, in a sermon preached at the Temple Church, also insists that the passions be fixed on their proper objects, which is to say that the passions are meant to glorify virtue and abhor vice.Footnote ²⁰

Bragge (1708) agrees with many previous thinkers that it is neither possible nor desirable ‘to root out’ and destroy passions, which just are vigorous tendencies toward what we regard as very good and conducive to our happiness and aversions to what we take to be very evil and pernicious. Good and evil will always affect us, both in this world and the next.Footnote ²¹ In this world, the passions are also motives to action, which move us through a strong commotion of ‘our blood and spirits’. In order to be moved in the right way, we must apply reason and religion to rectify our notions of good and evil and make an accurate estimate of the relative worth of goods: ‘He that Seriously and often thus employs his Thoughts, … will in time become as ‘twere Dead and Insensible to all the False Deluding Blandishments of Wealth, and Greatness, and Pleasure, and begot out of Danger of being transported by any Extravagant Degrees, of Passion, in the Pursuit of anything here below’.Footnote ²² Thus, the use of reason, with God's assistance, will not only enlighten us about what is genuinely good and conducive to our well-being (so that the passions move us according to their intended purpose), but it will also diminish our desires for (or love of) mistaken goods, the petty pleasures of this life.

4. Cudworth's and Clarke's Moral Rationalism

English theologian Ralph Cudworth died in 1688. His The True Intellectual System of the Universe was published in 1678, but was also published in several editions in the 1700's. A Treatise concerning Eternal and Immutable Morality was published posthumously, first in 1731, and A Treatise of Free Will, not until 1848. So, I here discuss Cudworth in the context of eighteenth-century thought, along with Clarke. Hume notes in the second Enquiry that the view that morality consists in necessary relations discovered by reason was first advocated by Malebranche, and then embraced by Ralph Cudworth and Samuel Clarke (EPM 3.34, n. 12). Hume famously describes Samuel Clarke's moral theory at Treatise 3.1.1.4 and then rejects what he takes to be his and Cudworth's moral rationalism by pointing to the inert nature of reason, which guarantees that reason could not be the source of morality, which is motivating or ‘active’ on its own. However, neither Cudworth nor Clarke actually appeared to believe that rational apprehension of necessary relations could move us on its own.

One of the Cambridge Platonists, Cudworth combines mechanistic, corpuscular explanations of nature with Platonic metaphysics, theism, and a defense of free will. Cudworth argues at length in Eternal and immutable Morality (EIM) against divine voluntarism that God's arbitrary commands cannot change the nature of a square into that of a circle, nor can they make something good or bad, just or unjust, that was not so by nature. He also argues that human minds have all ideas innately because they reflect the mind of God. Knowledge is acquired by an active process of cognition that involves recollection of these ideas, but also sense perception, which he says is necessary to acquire knowledge of the order in the external world. Cudworth isn't explicit about how moral knowledge fits into this scheme, but his treatment of morality analogously to geometry in its being composed of necessary, immutable truths implies that they are known in the same way geometrical truths are known, by our clear and distinct conception of them. Cudworth has no discussion of whether or how moral knowledge might affect actions, and passions are never mentioned at all in EIM. If we assume that he thought apprehension of morality, which is done by reason, could by itself motivate persons, then we could conclude that he thought reason on its own was motivating. However, the view that demonstrative reason was a motive was unorthodox, and Cudworth makes it clear in other writings that he did not think it. Both John Passmore in his book on Cudworth from the 1950's and contemporary philosopher Michael Gill in his more recent study of Cudworth contend that Cudworth is more aligned with sentimentalism than with rationalism in his motivational theory.Footnote ²³

In his Sermon Preached before the Honble House of Commons at Westminster (1647), Cudworth emphasizes the importance of character and internal motivation to living the religious, or the best, life. He writes that knowledge is ‘more excellent’ than riches and outward pleasures; yet, our happiness consists in ‘a certain divine temper and constitution of soul, which is farre above it’.Footnote ²⁴ We think it ‘a gallant thing to be fluttering with our wings of knowledge and speculation,’ but in fact, what is most important and productive of ‘sweet delight’ is to achieve an inner state of harmony between our will and God's. Later, Cudworth writes of God's effect on us: ‘[God] is always kindling, cheering, quickening, warming, enlivening hearts’.Footnote ²⁵ So, there is certainly evidence that Cudworth thought that the motivation to live the best life originated from certain internal sentiments, rather than from knowledge or reason. John Passmore, writes about the content of Cudworth's unpublished manuscripts that they show how misleading it is to think of Cudworth as one of Clarke's predecessors, whom Passmore characterizes as having the crudest form of rationalist psychology, with reason acting as ‘an impersonal arbiter’ remote from passion.Footnote ²⁶ Reason as intellectual apprehension is not a motive to action, for Cudworth. Passmore quotes Cudworth, ‘the first principle of motion in the soul is not, of course, reason and understanding’.Footnote ²⁷ Furthermore, ‘Mere speculative intellection without any inclination to one thing more than another without anything of appetite or volition… is not the beginning of all actions in the soul, but … instincts and inclinations are the spring and source of life and activity whence ends are suggested to us that provoke and incite endeavors …’.Footnote ²⁸

In A Treatise of Free Will (1838) (which, along with EIM, was intended as an extension of The True Intellectual System), Cudworth puts forward his alternative to faculty psychology with its divided mind. He characterizes the mind as an integration of reason, imagination, passion and appetite, with the contributions from these various sources ordered by the will. Among the features in the soul is an incessant desire, love of good, which is the source of motivation: ‘that which first moveth in us, and is the spring and principle of all deliberative action, can be no other than a constant, restless, uninterrupted desire, or love of good as such, and happiness. This is an ever bubbling fountain in the centre of the soul, an elater or spring of motion …’.Footnote ²⁹ The will is free, but it does not decide actions blindly and fortuitously; it is not indifferent to the alternative objects’ various degrees of goodness and evil and so it decides on the basis of deliberation and reasoning.Footnote ³⁰ Affirming Descartes's view that the will is the source of error when it doesn't wait for clear and distinct conception before affirming a proposition, Cudworth says that a person may ‘upon slight considerations and immature deliberations… choose and prefer that which is really worse before the better, so as to deserve blame thereby’.Footnote ³¹ Contingency in choice derives from the power to consider and deliberate more or less, not in the ability to act against our best judgment. Unlike the divided-soul view promulgated earlier in the seventeenth century, in the contest between dictates of conscience and the lower appetites, ‘there is no necessary understanding… coming in to umpire between them’. Instead, Cudworth says that the soul has a hegemonic, its self-governing power, which involves among other things, self-recollection, self-attention, heedfulness, and circumspection.Footnote ³²

In his Boyle Lectures of 1704 (A Demonstration of the Being and Attributes of God),Footnote ³³ Samuel Clarke presents his argument for the necessary existence of God and his description of God's attributes. His defense of free will against Hobbes and Spinoza is also a prominent theme. In his 1705 lectures (A Discourse concerning the Unchangeable Obligations of Natural Religion),Footnote ³⁴ Clarke discusses the source and nature of morality, which seems to situate him close to Cudworth in that arena. According to Clarke, ‘there is a Fitness or Suitableness of certain Circumstances to certain Persons, and an Unsuitableness of others, founded in the nature of Things and the Qualifications of Persons, antecedent to all positive appointment whatsoever; …’.Footnote ³⁵ These fitnesses determine truths of morality, such as that we should honor and worship God, that we should not defraud our neighbors, and that we should preserve the life of an innocent man. These truths are, as in Cudworth's theory, necessary and accessible by reason. For reasonable persons, their discernment of these fitnesses also directs their wills, when those wills are not corrupted by passions:

Clarke acknowledges a conflict between reason and passion in suggesting that when we act contrary to reason and so contrary to moral duty, it is because we are diverted either by ‘negligent’ misunderstanding or by passions like lust or greed. However, human understanding of demonstrative truths does not by itself lead to action, with no contribution from the passions. In his sermon, ‘The Government of Passion,’ (1710 or 1711),Footnote ³⁷ he says that, in God, there is no room for passion, because reason and understanding are perfect and therefore perfectly influence God's actions.Footnote ³⁸ In non-rational beasts, passions and appetites, are the only motivators. Human beings have a middle nature between the two, possessing both passions and reason. Passions and appetites ‘excite and stir them [“men”] up to Action, where their bare abstract Understanding would leave them too remiss’.Footnote ³⁹ It is human persons’ duty, however, to govern the passions with reason, where, when left alone, the passions would hurry them on to ‘exhorbitant and unreasonable’ things. So, following the theme in earlier writers, Clarke thinks the passions are useful when properly directed and make us diligent in pursuit of ‘those Actions of Life which Reason directs and the Passions execute’.Footnote ⁴⁰

Unlike Cudworth, Clarke insists on free will as the ability to choose to act against our best judgment.Footnote ⁴¹ In A Demonstration of the Being and Attributes of God, he is interested in showing that God's actions are neither necessitated (contrary to Hobbes and Spinoza) nor arbitrary (contrary to voluntarist views), but also done freely from reasons. Human freedom is a reflection of God's freedom. While the understanding may be determined to assent to a proposition perceived to be true, such assent is not a volition or cause of volition; it is a reason, rather than a cause, and to think otherwise is a confusion of ‘moral motives’ with ‘physical efficients’.

Clarke was pressed in correspondence by the Cambridge intellectual, John Bulkeley, on the matter why our assent or dissent from practical propositions should be any different from assent or dissent to speculative propositions. The latter is necessary, so, why should the former, ‘by which the man is determined to act’ not be equally necessary, and this, even though persons’ practical judgments may be at odds. For instance, one judges it good to act for his present pleasure and another to act for his long-term happiness. Clarke's reply is worthy of note:

So, a rational judgment of goodness or truth, which is compelled by perception, is inert, while the will is active, and it makes no difference what the subject of judgment is. In sum, Clarke's view attributes the execution of action to the passions, which can and ought to be guided by the judgments of reason.

5. Summary of Theses on Passion and Action in the Early Modern Writers

It is evident that a passion on the early modern view (a) involves a feeling of attraction or aversion to an object; (b) is evoked by an apprehension of an object's good or evil, which it represents; (c) is distinguished from reason or reason's operations; (d) is a normal part of human nature, not bad in itself; (e) is helpful when it does the practical bidding of reason or is moderated by reason; and (f) can lead to the pursuit of unsuitable objects when unruly and left unregulated by reason. Reason moderates the passions in various ways, depending on the account. (1) Reynolds holds that reason offers the passions a suitable object to seize upon and directs the passions to that end; Ayloffe and Burghope have a variation on that theme in which reason shows the ‘genuine Colours’ of objects to the passions. (2) In Descartes, ideas of genuine goodness produced by reason oppose the false notions of goodness promoted by the passions. (3) For Malebranche, our general proclivity to the Good is directed to proper objects by the understanding's representing particular instances of good. Cudworth's view is similar: an incessant love of good is served by our proper deliberation over objects. In none of these accounts is reason as a non-affective capacity providing an original motive to action.

6. Hume's Response

Hume commences his arguments concerning reason and motives in Treatise 2.3.3Footnote ⁴³ by citing the common perspective I noted in the beginning of this essay. He makes the following points: (1) The prevailing view in philosophy is that our passions are often opposed to our reason in providing motives to actions, and that people are virtuous when they conform their actions to the dictates of reason. Reason is eternal, invariable, and divinely originated, according to this view, while passions are variable and deceptive. (2) This accepted view of motivation and morality is mistaken on two counts, because (a) Reason can never be a motive to any action of the will, and (b) Reason can never oppose passion in directing the will. Hence, persons cannot be told to regulate their actions according to the dictates of reason and to oppose other forces (since they cannot be required to do what is impossible – namely, to be moved by reason).

What did Hume have in mind in highlighting the error of the thesis that reason can move us to action on its own, if none of his predecessors promoted it? First, Hume's characterizations of reason and passion are important to this discussion. Reason, he writes, serves to reveal to us conceptual connections in necessary truths or to derive inductive conclusions about the world. A large part of Book 1 of the Treatise concerns induction, or causal reasoning, and there Hume says that ‘all reasonings from causes or effects terminate in conclusions, concerning matters of fact; that is, concerning the existence of objects or of their qualities’.Footnote ⁴⁴ These conclusions are, from the perspective of the investigator, beliefs; so the products of reason are beliefs, and beliefs have cognitive content. Our beliefs about the world purport to copy our initial experiences and to represent to us the way the world is. In Book 3 of the Treatise, Hume defines reason as ‘the discovery of truth or falshood’ and defines truth and falsehood as an agreement or disagreement of our ideas to ‘relations of ideas’ (necessary truths) or to matters of fact, following the division of types of truths in Book 1.

Passions, on the other hand, make no reference to anything beyond themselves, he says; they are ‘original facts and realities’.Footnote ⁴⁵ In other words, passions are not copies of previous experiences and so contain no content that portrays the world in one way or another. They are feelings, a state I'm in, like being the height I am. Since passions do not refer to things in the world or represent something to be the case, as reason does, passions cannot contradict reason. This is, of course, a controversial view; not only do many early moderns disagree with it, but also contemporary philosophers have thought it far-fetched. (Annette Baier called it both ‘unfortunate’ and ‘silly’.)Footnote ⁴⁶ Descartes and many other rationalists explicitly characterized passions as representations, so one significant disagreement between Hume and these rationalists is over whether a mental state that represents could also motivate.

Given his characterization of reason and passion, it should be clearer now why Hume argued for the two theses, that reason alone does not motivate and that reason and passion cannot be opposed. Reason generates no impulses to action; it evaluates our representations for truth and falsity. This means that we are unmotivated (i.e. we feel no push or pull at all) when we engage reason, including (what some call) the use of rational intuition, the use of demonstration, and the use of probabilistic and inductive reasoning. This implies, in turn, that reason cannot oppose passion for direction of the will. Since only an impulse can oppose an impulse, individual passions, like anger, envy, and benevolence, which prompt us, cannot be opposed to reason, since reason gives us representations that do not by themselves prompt at all. Now I return to the puzzle why Hume featured so prominently the argument that reason without passion does not motivate.

First Hypothesis: Hume simply misunderstands the rationalist view. It would be easy to come away with the impression from Cudworth's EIM and from Clarke's Boyle Lectures that they subscribed to the thesis that reason alone is a motive. If Hume is not familiar with Cudworth's Sermon Preached before the Honble House of Commons at Westminster in 1647 or with Clarke's sermon ‘The Government of Passion’, he might very well have missed out on a critical component of their views on motivation. He certainly could not have read Cudworth's A Treatise of Free Will, given its publication date in the 1800's. Furthermore, it is easy to interpret most of Hume's predecessors as internalists, affirmers of the view that human beings are necessarily motivated by their judgments of the good. If the apprehension of good is done by reason and if that apprehension motivates, then it does look as though reason is motivating. But, of course, the impetus to action on most of the rationalist views I have discussed actually lies in an inborn proclivity to the good. Perhaps this is a kind of internalism, especially in Cudworth, who marries reason and feeling. It might be proper to read him as an internalist, but this still does not commit him to the view that motivation depends on reason by itself.

Second Hypothesis. Perhaps Hume regards the rationalist view of morality as relying on the thesis that reason alone can originate motives to action, even if those defending rationalist morality don't acknowledge this commitment, or argue against it. If so, Hume's argument may be intended as a reductio of the view that the content of morality is derived from reason. So, how might Hume's rationalist predecessors be committed by their moral theories to the notion that reason is by itself active?

If we accept the rationalist's subscription to teleology, which allows reference to an infused inclination of theological origin to goodness, then we can trace the source of proper motivation to that proclivity, rather than to reason. Senault and Ayloffe thought that all the passions include this God-instilled proclivity to good and away from evil and have the potential to be virtues because of that fact. The moderating effect of reason, along with God's grace, can make them worthy motivations. On Ayloffe's view, reason reveals to the passions the genuine features of objects. Motivation is initiated by passion's seeking the good, and reason is essential in identifying it. Bragge's view is similar: the passions are essential to action, but we need reason to show to them (or to us) the relative worth of goods. The hope is that we'll be moved away from the paltry pleasures of this world and toward the permanent goods of the next. If having a motive to any action is rooted in the original predisposition to good, then it looks as though reason need not create a motive to action from scratch. Instead, it presents a conception of the good for us to pursue. So, the views from Senault, Ayhoffe, and Bragge do not presuppose that reason is a motive to action, if interpreted within their own teleological metaphysics. Hume, however, regards their metaphysics as ungrounded.

Furthermore, Cudworth, I have shown, characterizes the mind as an integration of reason, imagination, passion and appetite, all orchestrated by the will. An incessant desire for the good is the source of motivation or the spring to action, but this desire's fulfillment requires the guidance of reason; in deliberation, we assess the degrees of goodness and evil produced by possible courses of action. When we go wrong, the fault lies in our failure to deliberate or to deliberate well, and we end up acting on the basis of unclear and indistinct ideas. Consequently, the source of error for Cudworth is like that in Descartes's account. It lies in erroneous representations. So, the opposition between reason and passion is between representations that originate contrary motivations. In this sense, reason is reputed to motivate, and yet, the origination of motivation still ultimately lies in the innate drive for the good.

I've noted that, for Clarke, the will is naturally turned to conforming itself to the fitnesses in the universe of which morality is composed, but it can be corrupted by lust, passions, and self-interest. Comprehension of necessary truths is not by itself sufficient to motivate human beings, who (unlike God) need the passions to excite them where bare abstract understanding leaves them cold. To achieve the aims of morality, the passions require the governance of reason, but reason cannot determine or cause the will. Judging is separate from acting, and the will is always free to act against the considerations reason offers. So, Clarke presents the quintessential picture of the will, advised by reason and by passion, with the ability to choose freely between them. He believes that the will's innate tendency to the good can be bent and diverted by the passions, a view he shares with Senault, Ayloffe, and Bragge. The best explanation how this happens is that the passions somehow represent objects to us as better than they actually are. When an innate tendency to the good is left unfilled because of passionate diversions, given that we are not forced to act by causal strength of the passions, the resultant action must be due to the will's heeding the passions’ (mis)representation of certain ends as good. That is, the passions embody judgments that are opposed to the judgments of reason. For instance, given the will's orientation to the good, I have (best) reason to obey God's commands because God's authority over me is a ‘fitness’ in the universe that specifies a moral duty; but I also have reason to fulfill my self-interested affections and passions, which are also good, even in disobedience to God. When I decide to follow reason, I freely conform my action to its assessment of the good, rather than to passions’ assessment. None of this implies that reason is originating a motive, since the will's attraction to the good is the root of the conation. It does imply that passion is representational, in additional to conative.

Hume, however, rejecting the metaphysical orientation of these philosophers and theologians, eliminates the idea that human beings are directed by a non-natural force toward goodness. Reference to divinely-instilled inclinations is groundless when this metaphysics is removed. Any theory that purports to account for an intrinsic motive to morality must found that motivation on the source of morality itself, since there is no justification for appealing to separate conative states mysteriously and necessarily connected to the comprehension of morality. In other words, to account for an internal connection between morality and the will, the motivational feature of morality must derive from morality's origin, namely, reason. So, when their metaphysical framework is removed, these intellectuals, believing that morality takes its content from reason and is accessed by reason, are also committed to the thesis that reason alone motivates. The problem with this reading is that Hume never explicitly says that he is offering such a reductio.

Third Hypothesis: Hume's defense of the thesis that reason is not a motive is crucial as a step, or as a sub-argument, in the overall case for the conclusion he draws in Book 3 of the Treatise, that morality cannot be derived from reason. There Hume methodically supports his conclusion about morality with the premises that reason does not motivate on its own and that morality does. So, perhaps he saw the thesis about reason's inertness as a logically necessary step to his conclusion about the source of morality.

However, in ‘the second Enquiry’,Footnote ⁴⁷ the support for that very conclusion is generally more direct. He does reference, in Section 1, the goal of moral speculations as begetting the habits of virtue and duty and notices that the cool assent of the understanding by itself cannot have this effect. However, in Appendix 1, ‘Concerning Moral Sentiment,’ he emphasizes five considerations that point to the conclusion that morality depends on feelings, but none of them uses the thesis that reason is not a motive. Instead he argues by reference to the features of moral judging and how we come to make the moral distinctions that we do. So, Hume is aware that he can defend sentimentalism with an argument different from the strategy he pursues in the Treatise.