The Religious Critique behind David Hume’s Philosophy

The tercentenary of the birth of David Hume (born May 7, 1711) has seen the publication of many tributes to the man and his philosophical achievements. These are certainly deserved, since Hume is one of the greatest of the British philosophers, and recognised as such. His works are still studied intensively today—especially his treatments of inductive reasoning, causation, personal identity and the foundations of morals. However, despite this high standing, and despite the close attention his works receive, the nature of his philosophy remains elusive. The point is not that various parts are under-explored; it is, rather, that what those parts add up to is not grasped. Indeed, in Hume’s case, his various sceptical arguments are so salient that it is often doubted whether there is a whole to which the parts belong. But it is usual for a philosopher’s work to be marked by an overall unity of purpose, such that the details of the various arguments fit into a pattern of inquiry or conviction—and are, indeed, rendered comprehensible thereby. This means, among other things, that there is a good chance that the more obscure parts of a philosophy will tend to be misconceived if not seen in the light of this larger whole. This is the case with Hume—and the various tributes to his work tend to illustrate the fact.

Hume’s most famous work nowadays is the long and complex Treatise of Human Nature, written in his twenties. It was not an immediate success, and, in his later years, he said of it that it “fell dead-born from the press”. This remark, however, says more than it seems, since it not only refers to its failure to be a best-seller, but also alludes to its author’s later view of it. Alexander Pope had written, in his “Epilogue to the Satires”, that “all, all but truth, drops dead-born from the press”, so Hume’s remark about the Treatise seems intended to admit that it deserved to fail. This does sum up his later attitude to it: he found it embarrassing, as many find the productions of their youth embarrassing—too much marked by the ardour and arrogance of youth. He much preferred subsequent versions of his philosophy, written a decade later: the Enquiry Concerning Human Understanding and the Enquiry Concerning the Principles of Morals, even describing the latter as, of all his writings, “incomparably the best”.

Hume’s own estimation of his works could not contrast more sharply with contemporary estimations. Nowadays, the Treatise commands centre-stage, and the later works are regarded as just diluted versions of the brilliant original—useful, perhaps, for comparative purposes, but hardly worthy of attention in their own right. Bertrand Russell set the tone by remarking, in his History of Western Philosophy, that the Enquiry Concerning Human Understanding was simply the result of Hume shortening the original Treatise “by leaving out the best parts and most of the reasons for his conclusions”. This amounts to saying that the later work is little more than intellectually-minded journalism, written for the sake of literary fame rather than for any serious purpose. This attitude has taken root, so much so that it is a commonplace amongst philosophers that, after writing the Treatise, Hume gave up serious philosophy.

This is an extraordinary deviation from the original estimation of the author. It would not be of so much moment if the philosopher in question were regarded as second-rate, as someone who enjoyed some successes despite, on the whole, trying to punch above his weight. But to dismiss so cheerfully the self-estimation of someone regarded as one of the most acute minds in the history of thought is quite astonishing. Moreover, its implicit denial of the existence of any overall unity to Hume’s writings must render the opinion suspect. It seems more probable that this view is popular simply because the modern reader fails to see the purpose of the Treatise and so fails to see why the later works might reasonably have been regarded by their author as fulfilling that purpose in a more satisfactory fashion. This suggests, then, that the way to search for the unity of Hume’s philosophy might be to take the later works seriously, to see what their message might be, and then to return to the intellectual thickets of the Treatise to see if the same purposes are discernible there.

In fact, the message of the later works is very plain. Despite it being often said that they are pale renditions of the Treatise, the fact is that they have a much more assertive stance. That stance is anti-religious. The first Enquiry sets out a materialist and determinist account of the workings of the human mind: a reductive account of thinking as the passive copying of sensations, and the linking of such copies by non-rational processes of association. It then explains our degrees of conviction about the world—our beliefs about what is necessary, probable or impossible—entirely in terms of a mechanical reliance on our past experience. It then applies this model to the main pillars of religious belief—belief in miracles and in intelligent design—and finds them wanting. The work concludes with the claim that the Inquisition has burnt the wrong books: it is the theological works that should be burnt, because they “contain nothing but sophistry and illusion”.

A similar message is discernible in the second Enquiry. It argues that morality is based not on any eternal truths, but simply on what human beings find “useful and agreeable”. This terminology is Hume’s translation of the Latin poet Horace’s endorsement of the utile et dulce. Hume is thus endorsing a standard of moral evaluation traceable not to Christian religious doctrines but to the classical world. But, more than this, he is endorsing the standard of Epicureanism—the ancient philosophical school (of which Horace was a member) distinguished by its materialist denial of an immortal soul and, more generally, by its anti-religious stance. And, if the message has been missed, Hume spells it out in the final section, where he denounces (in terms now more associated with Nietzsche) the self-restraint of religious values as nothing but punitive self-denial. The religious saint, he says, “may have a place in the calendar”, but is in reality an unbearable person, tolerable to general society only once he is dead; when alive, he is tolerated only by those “who are as delirious and dismal as himself”.

The later works are thus marked by a strongly anti-religious message. If Hume preferred them to the Treatise, then it is reasonable to suppose that he saw this message as at the heart of his philosophical endeavours, and judged the Treatise to be inferior because it failed to get this message across. If this view is on the right track, then it must be that the Treatise is itself intended to be an anti-religious work. This is an angle on that book which contrasts sharply with its modern treatment, in which preoccupation with its celebrated parts—concerning apparently unrelated topics such as causation and personal identity—tend to block off thoughts concerning the work’s larger purposes. Nevertheless, in Hume’s own day it was indeed seen as anti-religious in its tendency, so it is worth examining the book from this point of view. When we do so, we see that the parts all fall into place. 

The Treatise divides into three books: on the understanding (or rational powers), on the passions or feelings, and on morals. The first book itself divides into four parts: on the origin of, and connections between, ideas in the mind; on the ideas of space and time; on knowledge and probability; and on sceptical and other philosophical outlooks. Of these, only the last seems to have any obvious implications for religion, so the anti-religious interpretation of the book seems unlikely. A closer look, however, shows this not to be so.

The first part, on the origin and connection of ideas, offers an account of the workings of the mind in the same terms as the first Enquiry. Rationality is by-passed: what we think of as our reason, our thinking capacity, is really just the effects of sensation and associative effects. This is immediately significant because the ancient Platonic view, revived by Descartes to explain modern science, treated reason as belonging to an immortal soul, but the sensory capacities as belonging to the mortal body. Hume’s account thus immediately suggests affinities with materialist philosophies which deny the immortality of the soul. In fact, Hume’s account is clearly based on the materialist theory developed by Thomas Hobbes in direct opposition to Descartes’s views. For this reason, Hobbes was seen as an enemy of religion, routinely denounced as an atheist. He was treated as such (alongside Spinoza) by the Reverend Samuel Clarke in 1704, in the most famous series of lectures given to defend the harmony of Newtonian science with Christianity. Hume’s opening thus shows his colours on the most significant ideological division of the day.

The next part, on space and time, is more of the same. This will seem an unlikely topic for religious disputation, but at the time it commanded close attention. Hobbes had argued that to exist means to exist as a material thing—that we cannot conceive of any other form of existing, and thus that materialism must be true. However, Robert Boyle (who later funded the lecture series to which Clarke’s lectures belonged) had shown, with his experiments with his air-pump, that vacuums exist in nature, and therefore that existence and material existence are not the same. Hobbes’s argument seemed to have been undone. Hume, perhaps unwisely, enters into this dispute, arguing that, whatever the truth about the natural world, it remains the case that we cannot form a coherent idea of a vacuum. The implicit message is thus that materialism is not defeated.

The third part of the Treatise, on knowledge and probability, is one of the most famous, because it contains his arguments about the nature of our idea of causation. But what tends to be missed is the larger argument into which those arguments are meant to fit. Hume’s concern is to examine why we think that causation itself is necessary, that is, why we think that everything must have a cause. This conviction is so firmly entrenched in the history of philosophy that it is summed up in a traditional Latin formula: ex nihilo nihil fit, out of nothing, nothing comes. Hume’s aim in this part of the Treatise is to show that we know so little about the real nature of causation that we have no way of showing this to be true—that the necessity of causes is an idea generated in us by the force of experience, not one based on any sort of rational insight. But why is he concerned with this conviction? Because it is the key premise in the cosmological argument for the existence of God: the argument that God must exist because everything that exists must have a cause, and that God is the original cause because he is the cause of his own existence. This argument was Clarke’s central argument in his lectures, so once again Hume’s discussion is aimed at refuting the best-known philosophical case for religious belief.

The final part of Book 1, on sceptical and other philosophies, argues that we know, and even can know, very little about the true nature of the world. In this light, confident claims about religious doctrines can only be regarded as suspect, although Hume does not press that point. This part also contains the famous section on personal identity, in which Hume claims that we are unable to perceive an inner self. But this section immediately follows another section in which he argues that belief in an immortal soul is prey to exactly the same arguments brought against Spinoza’s notorious materialism, and that, indeed, materialism is better able to explain thought than the opposing view. In this light, the section on personal identity is a reply to the objection that we know we have an immortal soul because we can directly perceive it. (Descartes’s philosophy can be thought to affirm this.) Not so, says Hume: when we look within, we only perceive (inner) perceptions—we do not perceive a soul. The concluding section of this part, Hume’s “dark night of the soul” in which he eases his doubts by playing backgammon, thus falls into place. The preceding arguments have abolished confidence in the consolations of religion, leaving him feeling adrift in a world stripped of higher meaning. What then is left? The ordinary pleasures and engagements of the human world. It is in the activities of everyday life that we can find the purposes or consolations by which to live.

The first book of the Treatise has commanded most attention, for its length and its complexity. The second book, on the passions, has, by contrast, received considerable neglect. Even Hume lost interest in it: his later, shorter version of it may even deserve Russell’s judgment on the first Enquiry. Nevertheless, it has a point; and, again, it is anti-religious. It explains human action in terms of passions, which in turn are caused by external stimuli. The result is a fully determinist theory of action in which, again, reason is firmly demoted: reason is only “the slave of the passions”. But, more than this, the determining forces show that the passion of pride is inevitable whenever some fact related to ourselves causes us pleasure. Humility arises in similar fashion, only where the related fact causes us pain. When to this is added the hedonistic theory of motivation derived from the Epicureans (and repeated by Hobbes), it follows that we necessarily approve of pride and disapprove of humility. This is to invert the traditional values of Christianity. In fact, Hume’s discussion of pride is structured as a point-by-point rebuttal of the attack on the foolishness of pride mounted in the religious best-seller of the day, Richard Allestree’s The Whole Duty of Man. Here again, then, Hume prefigures Nietzsche’s similar attack on the psychology of value embedded in religious thought.

The third and final book of the Treatise concerns morality directly. Hume argues there that morality is not based in reason or knowledge, but in human feelings. As such, it applies only to human beings, and so makes no sense applied to a divine being. He goes on to present the theory of value described in the second Enquiry, and brings out the theory’s sympathies with ancient theories of greatness of soul (in contrast to Christian humility). Worse still, moral disapproval is classed as a form of hatred—a conclusion few moralists could abide. The longest section of this final part is, however, devoted to showing that justice is a human invention, adopted purely because of its usefulness. In this section Hume’s Epicurean debts and sympathies are most evident, because he offers there a version of the evolutionary theory of human development (later rendered in more detail and with characteristic pessimism by Rousseau) deriving from Lucretius’s Epicurean poem, Of the Nature of Things. The moral is that there is no sense of justice natural to the human being—justice is not natural, but an artificial device developed for the sake of peace and prosperity. It has an essential core—respect for what belongs to each—but is otherwise relative to the varying circumstances of human life. It has no application to a divinity, since no such being could be bound by those distinctively human circumstances. Theodicy is thus empty.

The disparate sections of the Treatise thus all hang together when seen as an extended attack on Christian orthodoxies. The human nature of which it is a treatise is thus too weak to penetrate into ultimate truths about reality, but is misled by its own psychology to fail to see this to be so. This nature is creative enough to manufacture principles of morality and justice by which to live, but, again, misled into mistaking them for realities which exist beyond our own practices and so attributable to a divine nature. In both its weaknesses and its strengths, then, human nature leads itself into forms of religious error. The problem, at bottom, is that we have allowed ourselves to adopt the self-flattering image of ourselves as the rational animal, the semi-divine hybrid creature made in the image of God—a conception first put sharply by Plato, and embedded in the Christian tradition. The message of the Treatise is that the truth is otherwise: that the human being is an animal, albeit a very clever one; and that, like the nature of other animals, human nature is geared to its special tasks, physical survival and the social co-operation on which that depends. Behind all the detailed arguments, then, the message of the Treatise is the same as the later works: religion is a muddle generated by false philosophy, and, worse, by misrepresenting our true nature and so formulating for us misleading and even damaging ideals, it is an enemy of the happy life. 

This, then, is Hume’s philosophy. Thus stated, it may not seem so remarkable—but that is because it is a viewpoint now so widely shared. Hume’s ultimate importance can thus be said to lie in his having been one of the first to present a coherent conception of the human being informed by the dramatic developments of modern science after Galileo, and to have argued that this project had profound ramifications for religious belief. In doing so, he was not alone, and was not even the first—in their different ways, Hobbes and Spinoza are predecessors—but he did capture one factor that the others had failed to see. That factor is that, in so far as the human being conforms to modern science’s causal conception of the world and all that is in it, to that extent the human claim to be capable of knowledge must be radically curtailed. On Hume’s account, beliefs arise in us necessarily, and there is little or nothing that reason can do about it.

This brings into sharp relief his philosophy’s Achilles heel. If reason cannot govern our thoughts, then our beliefs are not the result of rational judgment, and we have no solid basis for believing our beliefs to be true. Hume thus finds himself in the paradoxical situation of the sceptic, of cutting off the branch on which he is sitting. If this is not bad enough, he compounds the problem in the Treatise by denying that there is any serious content to the ideal of the love of truth. This means that he is unable to offer an adequate explanation for philosophical inquiry itself, including his own intense philosophical activity. What little he has to say on the subject only underlines the problem. In the end, then, Hume’s own dedication to philosophical truth is itself the principal stumbling-block to the theory of human nature he aims to teach. The conclusion must be, then, that, considered as a whole, the ambitious philosophy of the Treatise is a failure. It may be that he saw this himself, and for this reason preferred his later, more precisely-targeted, works.

The modern philosophy academic, in contrast, draws a different conclusion reflecting different interests and abilities. Less focused on religious questions, and also less interested in the very general philosophical question of the nature of the human being, he or she approaches Hume’s works with the somewhat blinkered eye of the modern specialist. For such a person, the parts of Hume’s philosophy matter more than the whole. It is no surprise, then, that it is the early Treatise, with its intense engagement with a wide range of fundamental philosophical problems, that has come to command most attention. The upshot is that Hume now receives the attention he deserves—if for reasons tangential to his own main enterprise. He would have found this a surprising state of affairs; but it is difficult to think he would have been displeased to find himself the object of so much attention. 

Dr Stephen Buckle is Senior Lecturer in Philosophy at the Australian Catholic University. He edited David Hume’s Enquiry Concerning Human Understanding, published by Cambridge University Press in 2007.