David Hume was born three hundred years ago, in 1711. The world has changed radically since his time, and yet many of his ideas and admonitions remain deeply relevant, though rather neglected, in the contemporary world. These Humean insights include the central role of information and knowledge for adequate ethical scrutiny, and the importance of reasoning without disowning the pertinence of powerful sentiments. They also include such practical concerns as our responsibilities to those who are located far away from us elsewhere on the globe, or in the future.
Hume's influence on the nature and reach of modern thinking has been monumental. From epistemology to practical reason, from aesthetics to religion, from political economy to philosophy, from social and cultural studies to history and historiography, the intellectual world was transformed by the enlightening power of his mind. In his own time, Hume’s ideas encountered considerable resistance from more orthodox thinkers. One result of this was his being rejected for philosophy chairs first at Edinburgh University and then at the University of Glasgow. Yet the influence of Hume’s ideas has grown steadily and powerfully over time. Indeed, as Nicholas Phillipson remarks in his insightful biography David Hume: The Philosopher as Historian: “David Hume’s reputation has never been higher.”
And yet some of Hume’s central but more iconoclastic ideas have not been brought adequately into contemporary discussion. This neglect continues despite the veneration of Hume as the quintessential “grand philosopher” of the Enlightenment. Many of Hume’s widely cited statements, which are often seen as “David Hume in summary,” fail to capture the largeness of the “understanding”—to use one of his favorite words—that Hume presented to us. The job is not made any easier by Hume’s tendency to make occasional remarks that suggest that he is “forgetting, or mis-stating, his [own] normative beliefs,” as Derek Parfit has recently pointed out in his farreaching philosophical work On What Matters. The issue is of importance, since some of the points that Hume seems to overlook in his occasional remarks had received decisive argumentative support in his own writings.
I BEGIN WITH a perspicacious remark that Hume made in 1751, in an essay called “Of Justice,” to be published later in An Enquiry Concerning the Principles of Morals. In the early days of the increasing globalization in which Hume lived, with new trade routes and expanding economic relations across the world, Hume talked about the growing need to think afresh about the nature of justice, as we come to know more about people living elsewhere, with whom we have come to develop new relations:
Again suppose, that several distinct societies maintain a kind of intercourse for mutual convenience and advantage, the boundaries of justice still grow larger, in proportion to the largeness of men’s views, and the force of their mutual connexions. History, experience, reason sufficiently instruct us in this natural progress of human sentiments, and in the gradual enlargement of our regards to justice, in proportion as we become acquainted with the extensive utility of that virtue.
The remark is of interest in itself, and also helps us to understand the general idea of justice, and its particular application to global justice, that can be seen to be part of the Humean line of analysis. But it can also be used to illustrate Hume’s general arguments for the need to interrelate ethics and epistemology, and moral reasoning and human sentiments.
The underlying approach to justice here contrasts with the influential view of Hobbes, according to which there has to be a sovereign state for us to entertain any coherent idea of justice. Hobbes was moved by the idea that institutional demands of justice can be met only within the limits of a functioning sovereign state, which is needed to establish and support the required institutions. While Hume was deeply concerned about the importance of institutions, on which he made many penetrating observations, he was reluctant to allow the idea of justice to be narrowed by the boundaries of sovereignty, as if there were no issues of global justice that could take us beyond our national borders.
The overarching concern in the idea of justice is the need to have just relations with others—and even to have appropriate sentiments about others; and what motivates the search is the diagnosis of injustice in ongoing arrangements. In some cases, this might demand the need to change an existing boundary of sovereignty—a concern that motivated Hume’s staunchly anti-colonial position. (He once remarked, “Oh! How I long to see America and the East Indies revolted totally & finally.”) Or it might relate to the Humean recognition that as we expand trade and other relations with foreign countries, our sentiments as well as our reasoning have to take note of the recognition that “the boundaries of justice still grow larger,” without the necessity to place all the people involved in our conception of justice within the confines of one sovereign state.
As it happens, contemporary theories of justice have largely followed the Hobbesian route rather than the Humean one. They have tended to limit their considerations of justice within the boundaries of a particular state. In an important essay in 2005 called “The Problem of Global Justice,” Thomas Nagel explained that “if Hobbes is right, the idea of global justice without a world government is a chimera.” The most influential modern theory of justice, namely John Rawls’s theory of “justice as fairness,” presented in his epoch-making book A Theory of Justice, concentrates on the identification of appropriate “principles of justice” that fix the “basic institutional structure” of a society, in the form of a cluster of ideal institutions for a sovereign state. This confines the principles of justice to the members of a particular sovereign state. It is worth noting that in a later work, The Law of Peoples, Rawls invokes a kind of “supplement” to this one-country pursuit of the demands of justice—but in dealing with people elsewhere, Rawls’s focus is not on justice, but on the basic demands of civilized and humane behavior across the borders.
Nagel, too, confines his analysis of global propriety not to the demands of justice, but to a “minimal humanitarian morality,” since he, too, takes the view that it is “very difficult to resist Hobbes’s claim about the relation between justice and sovereignty.” Hume’s exploration of how “the boundaries of justice” must “grow larger” in a more globalized world contrasts quite sharply with the Hobbesian way of thinking, and thus differs from the approach chosen by most of the contemporary theorists of justice. His approach has many implications for the way we should explore the idea of justice (a question I have attempted to address in my book The Idea of Justice, which draws also on other Enlightenment thinkers, particularly Adam Smith, Condorcet, and Mary Wollstonecraft).
THE REMARK BY HUME that I have cited throws light also on other parts of the understanding of ethics, epistemology, and practical reasoning that Hume presented. First, the remark fits well with Hume’s general argument that the understanding of justice must depend on what we know—that it is hard to make ethics stand free of epistemology. If there is a “gradual enlargement of our regards to justice” resulting from our expanding global contacts, this relates to Hume’s insistence that we cannot treat ethics as a freestanding field, dissociated from our understanding of the world, including what we know about each other. If we know nothing, or almost nothing, about a group of people, it is hard to talk about their needs, entitlements, or freedoms. We have good reason to pay more attention to the lives of others as we acquire greater knowledge of their lives, along with our growing connections with them.
Moreover, this understanding is not only important for ethics as a discipline, it tends also to be reflected, Hume argued, in people’s sentiments about whether we must take note of the lives of distant people as we come to know more about them. Hume clearly thought that this was a reasonable thing to do, and also that people’s sentiments would actually be influenced in precisely such a direction through the impact of their greater knowledge about others elsewhere. Hume’s understanding that the broadening of our concern is not only what reason demands, but what will affect our actual sentiments, makes such broadening difficult to brush off, since (as he put it in dealing with a related issue) “what affects us, we conclude can never be a chimera; and as our passion is engag’d on the one side or the other, we naturally think that the question lies within human comprehension; which, in other cases of this nature, we are apt to entertain some doubt of.”
The congruence of reason and sentiment, in this case, is in line with a general claim that Hume made elsewhere, in a somewhat exaggerated form (a form that he never seemed to spurn): that “reason and sentiment concur in almost all moral determinations and conclusions.” That such a concurrence could easily occur is worth noting partly because Hume also discussed cases in which there was no such concurrence (at least not spontaneously), and also because many formulations of “Hume in summary” concentrate almost exclusively on Hume’s remarks denigrating the role of reason in morality, in favor of sentiments, without noting that he did see them to be interrelated.
In the “summary Hume” that is frequently aired, it is also quite common to quote Hume against the possibility of reasoned ethics—for example, his speculation that reason is a “slave to the passions,” or his observation that “the rules of morality ... are not conclusions of our reason.” There are so many different things that Hume said on the relation between reason and ethics that it would be presumptuous of me to search here for some kind of definitive clarification of his overall position on the connections involved. But it is worth noting that immediately preceding the remark just quoted, about rules of morality not being conclusions of reason, Hume declares: “Morals excite passions, and produce or prevent actions. Reason of itself is utterly impotent in this particular.” (The italics are added.) The qualification “of itself” is important to note. This is, in fact, not an argument that reason is unimportant for morality or for motivating action. It argues only that reason cannot accomplish this entirely on its own.
Reason has to be about something, and clearly other factors, such as our knowledge of facts, are also involved in morality and practical reasoning (on which Hume wrote extensively). For reasoning to be influential in our lives and decisions, moreover, it has to sway people’s actual sentiments. (On this Hume also said a great deal.) This understanding can be seen in the context of delineating the way reasoning can work. These exercises of delineation do not in themselves undermine the important role of reasoning in ethics, nor entail any denial of the usefulness of reasoned argument about what we actually do know, or what our sentiments really are, or what they could be expected to be after critical scrutiny.
Hume had much use for reason whenever it could be sensibly deployed. The totality of his works richly illustrates his reason-dependent approach. While Hume expressed his frustration that “avidity alone, of acquiring goods and possessions for ourselves and our nearest friends” might well be “insatiable, perpetual, universal, and directly destructive of society,” or that people very often are too guided by self-interest in their thinking about justice, he also argued that there could be “moderation and abstinence” based on a reasoned understanding of the mutual dependence of people on each other. He points out, for example, that people “pull the oars of a boat by common convention for common interest, without any promise or contract,” and that their sense of justice is developed by thinking in “company and conversation.” The recognition that much of practical reasoning is conducted in company—a point that Gramsci would emphasize powerfully in his essays inL’Ordine Nuovo two centuries later—does not undermine the role of reasoning, but helps to characterize how it tends to occur.
The characterization also includes Hume’s treatment of what he called “experimental reasoning … which we possess in common with beasts, and on which the whole conduct of life depends.” At one level, this is, as Hume argued, “nothing but a species of instinct or mechanical power.” But experimental reasoning does not imply any absence of reasoning. The instinct that makes a person reluctant to put his or her hand into the fire is, as Hume discussed, both an instinct and an example of a species of reasoning. The instinct to keep our hand out of the fire is not unrelated to our seeing—and learning from others—what happens if an object like a hand happens to go into the fire, and this is what experimental reasoning is about. The net effect of this dual role is to extend the reach of reasoning—even to animals (the discussion cited here comes in an essay called “Of the Reason of Animals”)—rather than to deny that this type of decision could be compatible with any kind of reasoning since it is, in an immediate sense, just an instinct.
SIMILARLY, HUME’S insistence that the reach of ethical reasoning is, of necessity, limited is also a part of this delineation. Indeed, Hume thought that reasoning has a confined reach even in central issues of epistemology. We may not ever be able, as Hume points out, to “satisfy ourselves concerning any determination, which we may form, with regard to the origin of worlds, and the situation of nature, from, and to eternity.” But this did not prevent Hume from trying to see what can be sorted out through reasoning. Indeed, it is these efforts of reasoning that made Hume such a suspicious character to the religious establishment of his time. We have reason to pursue knowledge to the extent we can, undeterred by the recognition that we may not be able to resolve all the issues that arouse our interest and curiosity.
Great harm has been done to contemporary decision theory and the theory of rational choice by the presumption that reasoning can be given a role only if it is able to resolve every decisional problem. Indeed, understanding the incompleteness of our ordered information about the world, or stopping at incomplete—but articulate—orderings of alternative courses of action, is an integral part of human reasoning. The large subject of learning to rely on partial resolution, which is quite crucial in modern social choice theory, clearly has Humean antecedents. The usefulness of reasoning is not dependent on its being able to solve every problem at hand.
This understanding, which is still inadequately appreciated in decisional analysis, was championed already by Hume more than a quarter of a millennium ago. And I should add here that even the Hobbesian insistence on the need for a sovereign state for the possibility of saying anything coherent about justice, which allegedly makes any contemporary statements on “global justice” to be a “chimera,” closely relates to the assumption that no idea of justice can be viable unless it is able to resolve every putative claim of injustice. In this “all or nothing” view, we cannot seek an enhancement of justice through preventing famines, genocides, or gross subjugation of women in the world until a global sovereign state starts functioning and can meet all the institutional needs of a globally just world. This is indeed a far cry from Hume’s understanding of the gradual enlargement of “the boundaries of justice” in the world. And that understanding remains critically relevant as we try to remove patent injustices that plague our world.
WE LIVE IN a world in which a global vision is of extraordinary importance, and many of Hume’s arguments—on the broadening of the boundaries of justice, on the importance of knowledge in ethics, on the diversity of forms that human reasoning can take—are of central importance to such a vision. Our interdependent lives make nationally isolated pursuits of justice (segregated through sovereign states, whether or not involving “sovereign debts”) altogether inadequate in the way that Hume already diagnosed them to be in his far less integrated world. Like his friend Adam Smith, he was much concerned with broadening the narrow limits of contemporary ethical thought—a need that remains alive today.There are many different implications of Hume’s arguments for the necessity of broadening the understanding of justice as our knowledge about other people expands. The connection between reasoned ethics and the “progress of human sentiments” may help to explain the emergence of the so-called “anti-globalization” movement as a search—despite its misleading name—for a new global ethics with rapidly expanding economic globalization. A sense of cross-border grievance about massive global inequalities, with a particular concentration on the lives of the most deprived people in the world, finds expression—often quite crude expression—in these typically disorderly movements, which bring citizens from rich and poor countries to assemble in protest, in one city after another, converging from across the world. If we see these cross-border agitations, despite their simplistic slogans and noisy protestation, as part of a groping for more global justice, broadly in line with Hume’s anticipation of a “natural progress of human sentiments,” then the underlying ethics of at least one large part of these movements becomes easier to understand.
The search for more justice in the global world can also benefit from the Humean admonition about the need for empirical knowledge, particularly—in this case—about what works and what does not work (a subject that is central to contemporary development economics). This applies not only, say, to different forms of aid and assistance, but also to the role of education and health care in advancing development, including economic progress. Empirical understanding is also relevant for assessing how the market economy works, what it achieves and what it does not. If the economic crisis of 2008 is at least partly a reflection of being misled by the pure theory of infallible markets, it brings out sharply the practical importance of real knowledge about how markets can be expected actually to work.
The Humean pointer to the growing “boundaries of justice” with our knowledge about distant people also has immediate bearing on inter-generational ethics, particularly on the importance of a clearer understanding of the long-run impact of our environmental behavior on the lives of future people. The expansion of knowledge about how the lives and the predicaments of future generations may be affected by environmental deterioration, or—to take a different example—through nuclear proliferation, can much broaden the demands on the “boundaries of justice.” The importance of epistemology for ethics—for example, about whether or not there is “global warming” and to what extent human behavior is contributing to it—has never been stronger. This is particularly worth emphasizing, since the pursuit of serious knowledge relevant to justice, varying from economic causation to environmental connections, seems to be under some threat in the contemporary world.
Our world and our future may well depend on the understanding that we bring to bear on the interconnections between what we know, what we can reasonably expect, what we feel, what we have reason to consider, how our reasoning can come in many different forms, and how we should think about justice and injustice. There can be few things that are more important than that right now—no less than it was in Hume’s own time.
Amartya Sen teaches economics and philosophy at Harvard University and received the Nobel Prize in Economics in 1998. He is the author, most recently, of The Idea of Justice (Harvard University Press). A different version of this essay was given as a tricentennial commemorative lecture at Edinburgh University. This article originally appeared in the December 29, 2011, issue of the magazine.