Musée Voltaire, Ferney-Voltaire, France/Erich Lessing/Art Resource

‘Voltaire in his night shirt, putting on his trousers while dictating to his secretary, at his house in Ferney, France’; painting by Jean Hubert, eighteenth century

What are we to make of the eighteenth- century Enlightenment? For over two hundred years the legacy of its most prominent thinkers, from Locke and Newton to Voltaire, Hume, Diderot, and Kant, has been the subject of bitter debate. Its supporters hail it as the source of everything that is progressive about the modern world. For them, it stands for freedom of thought, rational inquiry, critical thinking, religious tolerance, political liberty, scientific achievement, the pursuit of happiness, and hope for the future. By contrast, its enemies accuse it of “shallow” rationalism, naive optimism, unrealistic universalism, and moral darkness.

From the start, there was a conservative and clerical opposition, a Counter-Enlightenment that defended traditional religion against what appeared as a materialistic and skeptical onslaught, one that encouraged immorality, pornography, and contempt for the established order. In the French revolutionary Terror the Enlightenment’s critics saw the confirmation of all that they had predicted. The utopian desire to achieve the perfectibility of man had led inexorably to tyranny and atrocity.

From the late eighteenth century it became common for Romantic philosophers to argue that, in their supposedly exclusive reliance on reason, the thinkers of the Enlightenment had disregarded the bonds of history, myth, and tradition that held societies together. Nineteenth-century nationalists thought it wrong to propose a single set of values for all the world’s peoples. They preferred cultural diversity to moral uniformity. The Oxford English Dictionary reflected Victorian prejudices when, in a notorious entry (still there in its 1989 reissue), it defined “Enlightenment” as a term

sometimes used…to designate the spirit and aims of the French philosophers of the 18th c., or of others whom it is intended to associate with them in the implied charge of shallow and pretentious intellectualism, unreasonable contempt for tradition and authority, etc.

In the twentieth century, the Enlightenment was accused of a coldly amoral obsession with technological domination and a determination to achieve human perfectibility that allowed no scruple to stand in its way. At the Nuremberg trials in 1946, the lawyer defending Ernst Kaltenbrunner, charged with crimes against humanity, explained that Nazi atrocities were the legacy of eighteenth-century secularism. In the year after Nuremberg, the “Frankfurt School” social theorists Max Horkheimer and Theodor Adorno, in their Dialectic of Enlightenment, portrayed the Marquis de Sade as the embodiment of Enlightenment morality, and twentieth-century barbarism as its logical culmination. To some, the Eichmann trial of 1961 seemed to confirm this notion of the Holocaust as a characteristically “Enlightened” scheme of social engineering, carried through with bureaucratic rationality.

It is not surprising that historians should have protested against these travesties. The philosopher Ernst Cassirer, in his The Philosophy of the Enlightenment (published in the year before Hitler’s accession to power and his own departure from Germany), demonstrated that, whatever the Enlightenment was, it was anything but “shallow.” In the 1960s, another German-Jewish refugee, Peter Gay, wrote a very fine two-volume study, The Enlightenment: An Interpretation, designed to rescue the movement from the charge of “superficial rationalism, foolish optimism, and irresponsible Utopianism”; he reaffirmed the permanent value of its “humane and libertarian vision.”

Yet the disparagement of the Enlightenment continued. In the later twentieth century Michel Foucault represented its search for knowledge as just another bid for power and domination. Postmodernists rejected the notion that moral and political values might be universal. Different cultures, they maintained, should be allowed to determine their own priorities. Schemes for social amelioration were dismissed as intolerably Eurocentric, and the civilizing mission was portrayed as a mere cover for colonial oppression. Green lobbyists blamed environmental decay on the Enlightened drive to exploit the natural world for human benefit. Feminists noted that the philosophes were all men and rebuked them for their supposed indifference to problems of gender.

Once again the historians hit back. In three huge and enormously erudite volumes, Jonathan Israel claimed that there was a close fit between twenty-first-century liberal values and those of what he called the Enlightenment’s “radical” wing, deriving, he argued, from the thought of Spinoza. In his view, they remained “by far the most positive factor shaping contemporary reality and those strands of ‘modernity’ anyone wishing to live in accord with reason would want to support.”1 Similarly, John Robertson argued in his The Case for Enlightenment (2005) that, by generating the new science of political economy, Enlightenment thinkers had correctly identified the best way forward for economically backward regions like Scotland and southern Italy.

The most remarkable feature of this seemingly endless debate is that all its participants appeared confident that they knew what “the Enlightenment” was. Yet although many people in the eighteenth century referred to les Lumières, Illuminismo, and Aufklärung, the meanings they gave those terms seldom overlapped. In 1784 Kant famously defined Aufklärung as an emancipatory mental process, the achievement of intellectual maturity through the ability to think for oneself. But he did not suggest that there was an organized plan to propagate a new philosophy and reform the human condition. Earlier in the century a group of mainly French men of letters had self-consciously set out to drive away what they saw as the mental darkness of the past. But only in retrospect did the idea of the Enlightenment as a coherent intellectual movement take root. Not until the late nineteenth century did English speakers begin to describe le siècle des Lumières as “the Enlightenment.”


Nowadays, its friends and its enemies alike refer freely to “the Enlightenment project,” a term popularized in 1981 by the philosopher Alasdair MacIntyre. He defined that project as an attempt to provide “an independent rational justification of morality,” and he claimed that it had failed. Yet historians point out that the Enlightenment had not one but many projects. Its starting point was a desire to improve the human condition by the critical application of the intellect, unconstrained by religion or tradition. But this could lead to vastly different conclusions.

Some scholars regard secularism as the essence of the Enlightenment. Others emphasize its humanitarianism, its reforming zeal, or its belief in progress. But the thinkers of the “Enlightenment” were too diverse to be gathered under any one label. And how can any single definition comprehend the huge variations in their tone and style, from the wit and elegance of Voltaire to the ponderous solemnity of Kant? Perhaps all that can be said with certainty is that within the immense variety of eighteenth-century intellectual life there was a cluster of critical, skeptical, and progressive attitudes that historians have found it useful to bracket together as “Enlightened.”

Even then, historians hover between the notion of a single Enlightenment, extending throughout Europe and North America, and a plurality of separate national Enlightenments, each with its distinctive characteristics. Jonathan Israel distinguished between a “radical” Enlightenment, atheistical, democratic, and anticolonial, and a mainstream, “moderate” Enlightenment, prepared to compromise with the church and the existing social order. Others contrast the “high” Enlightenment of intellectuals with the “low” Enlightenment of Grub Street journalism and popular debate.

There is also disagreement about when the Enlightenment began: in the mid-eighteenth century, with the Parisian philosophes; in the late seventeenth century, with Baruch Spinoza, John Locke, and Isaac Newton; or even earlier with Francis Bacon, René Descartes, and Thomas Hobbes? And did its uniqueness consist in the ideas of its leading thinkers? Or was it rather to be found in its distinctive social history, evidenced in the widening of the public sphere through reading, writing, journalism, book publishing, and intense discussion, conducted in cafés, coffeehouses, clubs, academies, and Masonic lodges? In such places, the ideas of the philosophes circulated in simplified popular form.

Anthony Pagden is a distinguished historian of early modern thought, but he too is defeated by the problem of definition. He begins his learned, eloquent, and sometimes passionate book by describing the Enlightenment as “that period of European history between, roughly, the last decade of the seventeenth century and the first of the nineteenth.” This is not a helpful start, since however broad a meaning is attached to the term, a great deal of the thinking and writing of the eighteenth century was very far from being “enlightened.”

Just how far is well illustrated by Paul Kléber Monod’s thoroughly researched and highly informative account of the revival in late-eighteenth-century England of occult ideas and practices that are usually thought to have been effectively sidelined by the natural scientists a hundred years earlier. They included alchemy, astrology, hermeticism, Rosicrucianism, Behmenism, Theosophy, Swedenborgianism, occult Freemasonry, magnetic healing, prophetic visions, and the conjuring of spirits.

Monod argues that these activities had an affinity with the Enlightenment, in that their practitioners were implicitly following Kant’s injunction to think for themselves. But the “enlightenment” that was thought to come from personal revelation to ritually purified initiates was very different from the enlightenment brought by the exercise of human reason; and the quest of Freemasons and others for ancient Egyptian wisdom seemed ridiculous to those who were seeking to advance human knowledge by scientific study. Monod is right, though, to say that it was only in an atmosphere of Enlightened tolerance that such unorthodox cults could have been openly practiced.

Pagden quickly abandons his initial equation of the Enlightenment with a period of history. Instead, he characterizes it as an intellectual process, concerned with understanding “the historical evolution of the human mind.” He maintains that, for all their differences, the Enlightened philosophers really were engaged in a single “project,” but his definition of that project is not quite the same as MacIntyre’s. He defines the project as the pursuit of an entirely secular “science of man” that would demonstrate the existence of a universal human identity. To back up this interpretation, he draws lavishly from the best-known writers of the French Enlightenment, especially Montesquieu, Voltaire, D’Alembert, Diderot, Holbach, Rousseau, and Condorcet. He also finds room for the Englishmen Locke and Shaftesbury; the Scots David Hume and Adam Smith; and the Germans Leibniz and Kant. He makes only a few passing references to the Dutch Jew Spinoza, who Jonathan Israel argued was the crucial influence on the “radical” Enlightenment.


Pagden indeed makes little attempt to engage with the reinterpretations of the Enlightenment offered in recent years by his fellow historians. He is not much interested in its diffusion at a popular level; and the name of Robert Darnton, author of much the most invigorating writing on that subject, does not appear in his bibliography. Joseph Wright of Derby’s painting A Philosopher Lecturing on the Orrery adorns his dust jacket, but there is no discussion of the progress of astronomy or the other physical sciences. Neither does Pagden consider the projects for political, economic, and penal reform emphasized by students of the Italian Enlightenment like Franco Venturi and John Robertson. His is very much an essay in intellectual history narrowly defined, an analysis of ideas with little attempt to locate them in the social practices of the age.


British Library Board

The frontispiece to the second part of Joseph Glanvill’s Saducismus Triumphatus (1681), a popular collection of stories claiming to document, as Paul Kléber Monod writes in Solomon’s Secret Arts, ‘that supernatural events were commonplace and happened to very ordinary people’

The Enlightenment, for Pagden, is the source of today’s “broadly secular, experimental, individualistic, and progressive intellectual world”; and he applauds what he sees as its denial that religion can provide knowledge about either man or nature. Above all, he regards the Enlightenment as proclaiming the unity of the human race and the existence of a global society whose inhabitants are all entitled to the same basic human rights. For him, “the most important of all the claims of the Enlightenment” was its cosmopolitanism. Without it, he says, we would be unable to speak today of the “international community” or of “crimes against humanity.” Its long-term legacy has been the League of Nations, the United Nations, the European Union, the International Court of Justice, and the Universal Declaration of Human Rights.

Like many before him, Pagden has taken what he admits was only one strand of Enlightenment thought and made it the key to the whole “project.” In one form or another, cosmopolitanism was undoubtedly a prominent theme in Enlightenment thought, though whether it was so widely endorsed and so central a preoccupation is more debatable. Pagden’s desire to provide modern cosmopolitanism with an intellectual genealogy reminds one of the observation of the intellectual historian James Schmidt that when someone invokes “the Enlightenment project” it usually tells us more about the writer’s desire to provide historical legitimacy for some current commitment than it does about the thought of the eighteenth century.

The concept of a single human community had a long prehistory. It had been elaborated by Cicero, Seneca, and other Roman Stoics; and it was upheld by the scholastic philosophers of the Middle Ages, who regarded all human beings as subject to the same divinely inspired natural law. In the early modern period, however, the Protestant Reformation and the Scientific Revolution destroyed the scholastic consensus. By the mid-seventeenth century, Pagden believes, Christianity was failing to provide the intellectual and moral certainty it once had done; and it seemed as if the vacuum would be filled by writers like Hobbes, who presupposed not a unified human race but a state of mutual hostility.

The Enlightenment’s philosophers therefore, in Pagden’s account, attempted to recover the old vision of a benign and unified humanity, but without including God as its creator. Their notions of sympathy, pitié, and natural sociability made the capacity to respond to the feelings of others one of humanity’s defining attributes. Out of this grew a concern for the welfare of those who belonged to other communities. Pagden is perhaps unduly dismissive of the Christian antecedents of this attitude. Concern for the welfare of all mankind had underlain centuries of missionary activity, and it permeated the scientific circles of the seventeenth century. Like Francis Bacon before him, the pious Robert Boyle commended his fellow natural philosophers for taking “the whole body of mankind for their care” and practicing “so extensive a charity, that it reaches unto every thing called man, and nothing less than an universal good-will can content it.”

Similarly, in 1655 Oliver Cromwell justified his attack on Spanish possessions in the West Indies by citing the “utmost barbarity” with which the Spaniards had treated the native Americans. Since all men were brothers, he claimed, “all great and extraordinary wrongs done to particular persons ought to be considered as in a manner done to all the rest of the human race.”

Underlying the cosmopolitanism of the Enlightenment was the determination to construct a science of morals without drawing on religion (though the philosophes admitted that the doctrine of divine rewards and punishments was a useful device for keeping the lower orders in their place). For David Hume, philosophy was the inductive, experimental science of human nature. His hugely influential writings provided a theory of knowledge and a secular ethics founded on the “science of man.” Pagden points out that the same search for a common human nature underpinned the Natural History of the Comte de Buffon and the numerous “conjectural” or “philosophical” histories that attempted to trace the stages by which human beings had moved from “savagery” to “civilization.”

A similar motivation underlay the scientific voyages by Bougainville, Cook, Lapérouse, and others to the islands of the South Pacific, whose inhabitants, as one of the founders of the Society for the Observers of Mankind remarked, could be inspected, “like ancient and majestic monuments from the origins of time.” This preoccupation with human evolution was as much concerned with the future as the past, for, as Pagden says, “the attainment of a true ‘civilization’ was all that ‘Enlightenment’ was about.” The philosophes assumed that all peoples would move in the same direction. International commerce, they thought, would provide the essential link between nations, softening manners and creating a world society based on reciprocity. China’s intellectual stagnation was an awful warning of what could happen when a hitherto progressive society deliberately cut itself off from communication with the rest of the world.

True cosmopolitans did not allow patriotism to exclude a larger loyalty to the human race. We should love our country, said Adam Smith, “merely as a part of the great society of mankind.” For believers in what Kant called “global patriotism” the obvious next step was the political unification of humanity, underpinned by an international law. Pagden describes some of the various eighteenth-century projects for global government or an approximation to it. They ranged from the scheme of the Prussian professor Christian Wolff for a world state, with laws “approved by the more civilized nations,” to the plan put forward during the French Revolution by another Prussian, Baron “Anarchasis” de Cloots, for a “Whole Republic of Man.”

In Pagden’s view, the culmination of Enlightenment cosmopolitanism was Kant’s Toward Perpetual Peace (1795), a project for a federation of nations rather than for a univeral republic. He sees this as a foretaste of today’s European Union, which, despite its current travails, he hopes will eventually provide an alternative to “the gradually faltering nation-state.” The member states of Kant’s federation were bound to recognize a “cosmopolitan right” (Weltbürgerrecht) of “hospitality,” whereby a stranger was not to be turned away if that would lead to his death. Although this was a highly attenuated version of the rights recognized by seventeenth-century natural lawyers, it is, just, possible to see in it an anticipation of the Universal Declaration of Human Rights of 1948.

As Pagden notes, cosmopolitan sentiments came easily to the European intellectual elite, who had for several centuries constituted the so-called Republic of Letters, corresponding with each other in a common language, first Latin, then French. They also come easily to Pagden, for he is a much-traveled scholar who has studied and taught on three continents, unlike Kant who, ironically enough, never went more than ten miles from his native Königsberg. Yet Pagden tends to see Enlightenment cosmopolitanism as an abstract concept constructed by philosophers, rather than the natural consequence of the lifestyle of the eighteenth-century aristocracy, most of whom traveled extensively, spoke French, subscribed to a common code of manners, both in peace and war, and shared tastes in literature, music and art.2 Science too was an international activity and so was Freemasonry.

Since Pagden’s aim is to explain how a small number of intellectuals came to refer to themselves as “citizens of the world,” these circumstances need to be taken into account. Similarly, the revival of internationalist ideals in the later twentieth century surely owes less to the rediscovery of eighteenth-century projects than it does to the growth of a global economy, the risks of a nuclear war, the threat of climate change, and the unification of the world brought by the electronic media.

In practice, there were limits to the philosophes’ vision of one common humanity. Some, though not all, shared the prejudices of the age about women, Jews, Africans, and Native Americans. In a notorious footnote, Hume declared that there were four or five species of men, all “naturally inferior to the whites”; and Kant likewise envisaged mankind as a hierarchy of four races, with the Europeans on the top and the Africans at the bottom. Pagden suggests that Kant came to regard African backwardness as the result of the experience of slavery, rather than proof of their inherent inferiority. He could have added that Hume subsequently retracted his assertion about the four species of men, though he reaffirmed his negative view of blacks, for which he had a climatic explanation.

Less reassuring is the case of the Swiss jurist Emer de Vattel, whom Pagden commends for his vision of a harmonious world order where men would live as fellow citizens of the universe. Pagden does not remind us that Vattel also justified genocide, maintaining that people who (like “some modern Tartars”) inhabited fertile countries, yet failed to cultivate the earth and lived by plundering others, deserved “to be extirpated as savage and pernicious beasts.”3 Many Enlightenment thinkers were not entirely free from the racist assumptions that came to dominate the nineteenth-century versions of “the science of man.”

Pagden concludes with a vigorous attack on the Enlightenment’s present- day enemies. He is appalled by resurgent religion, most of it, in his view, devoid of theological content and essentially “pathological.” He singles out “Muslim extremists,” who seek to replace Western modernism by an ethics of belief, and he deplores the nihilism of the Christian “megachurches” of the United States. In both cases, he thinks, their religion is an ideology of protest that will die away, if and when the grievances against which they are rightly protesting die too. He takes comfort from the fact that, although confessed unbelievers reportedly number only 11 percent of the world’s population, they are located in the wealthiest and best-educated parts of the world.

His other adversaries are the “communitarian” philosophers, particularly Alasdair MacIntyre and Charles Taylor. He regards them as enemies of Enlightened cosmopolitanism, localists who hold that humans are lost without the religion, traditions, and distinctive brands of rationality provided by membership in some smaller community. Communitarians, he believes, hold that no one outside the community is entitled to pass moral judgment on what happens within it. For them, there can be no such thing as “global” justice, because justice depends on shared conventions and different communities have different conventions.

In opposition to the moral relativism of the communitarians and the irrationality of “pathological” religion, Pagden reasserts what he regards as the essential values of the Enlightenment, firmly based, he believes, on a detached inquiry into what it means to be human. Today they are shared, he thinks, by “most educated people, at least in the West.” For, he says, they would surely agree that the world can be improved by the application of scientific knowledge, that human nature is much the same everywhere, that there are universal notions of justice, that all members of the human species are entitled to certain rights, and that there are minimum ethical standards to which all cultures should conform.

Immanuel Kant; artist unknown, circa 1790

Here Pagden follows Diderot and Kant, who did not allow their respect for cultural differences to lessen their commitment to universal principles of human freedom. While accepting that different ways of life were incommensurable, they nevertheless drew the line at slavery and the Indian caste system.4 Similarly, Pagden declares:

No one today would describe as “civilized” any people, or culture or law or religion, that refused to extend the same legal rights to women as to men, that sanctioned female infibulation…or that forbade women to drive, denied them an education equal to men, or obliged them to wear disfiguring clothing in public.

One has only to think of the millions of people in the world who, while describing themselves as “civilized,” would react unfavorably to this assertion, to realize that the acceptance of cultural diversity and a commitment to human rights are not easily reconciled.

The “Enlightenment project” will remain seriously incomplete so long as some of the world’s largest religions and political systems refuse to accept the conclusions arrived at by the “science of man.” How can we ever persuade them to do so?