Despite the seemingly unshakable moniker “The Age of Reason,” it has long been known, at least among those familiar with the scholarly literature on the period, that almost none of the key thinkers who made up the Enlightenment believed that reason alone could or should rule the world. On the contrary, most of the leading thinkers of the eighteenth century held that it is not reason but the passions or sentiments that serve as both the chief motivating force of human action and the ultimate basis from which moral norms are derived. Hence, as Sylvana Tomaselli writes, “it would be mistaken to think of reason as the rallying cry of Enlightenment thinkers except in so far as it was opposed to faith, and the Age of Reason opposed to the Age of Superstition. If one's gaze shifts away from the battles with l'Infâme, then the ‘Age of Sentiments,’ ‘Sentimentality,’ ‘Feelings,’ ‘Passions,’ ‘Pleasure,’ ‘Love’ or ‘Imagination’ are apter titles for the movement of ideas in the eighteenth century.”Footnote ¹ Moreover, Enlightenment thinkers were consistent—even obsessive—in their denigration and mocking of system-building. They advocated relying on experience and experiment rather than on a priori first principles, and, so far from having boundless confidence in the power of unaided reason, they continually stressed the limits and fallibility of human understanding.Footnote ² The Enlightenment conception of reason was, in short, far humbler than that found in the great metaphysical thinkers of the seventeenth century such as Descartes, Malebranche, Spinoza, and Leibniz. Thus, Peter Gay rightly declares that “the Enlightenment was not an Age of Reason, but a Revolt against Rationalism.”Footnote ³

Yet it is still frequently claimed that the thinkers of the Enlightenment—especially the French Enlightenment—embraced rationalism in the political sphere, meaning that they advocated subjecting all laws, institutions, and practices to the withering light of reason, and discarding those found wanting by its standards. Many critics have contended that this kind of political rationalism invariably leads to misguided attempts at social engineering and upheavals like the French Revolution, and contrast it with a more practical, pragmatic outlook that aims to repair or reform existing institutions rather than to form a wholly new “rational” order from scratch. The view of the philosophes as misguided political rationalists in this sense has a long and distinguished history. It arose soon after the end of the French Enlightenment, when thinkers such as Edmund Burke and Joseph de Maistre blamed the philosophes and their writings for prompting the excesses of the French Revolution.Footnote ⁴ This view was carried on in the nineteenth century by thinkers as diverse as G. W. F. Hegel and Alexis de Tocqueville, and it reached a kind of high point during the Cold War, when the dangers of rationalism in politics were a key area of concern for scholars ranging from Michael Oakeshott and Friedrich Hayek to Isaiah Berlin and Jacob Talmon.Footnote ⁵

Today, the idea that the philosophes were political rationalists is simply taken for granted by many political theorists and philosophers. It is true that scholars who specialize in the thought of one or the other of the philosophes—some of whom will be cited later in this essay—often recognize that they were far from believing that reason could solve all political problems. Yet the handful of more nuanced studies of individual philosophes has done little to change the general view of the French Enlightenment, especially because political theorists and philosophers rarely pay much attention to thinkers of eighteenth-century France outside of Montesquieu and Rousseau; the idea that the other philosophes were utopian rationalists is left largely unquestioned in the literature. Predictably, critics of the Enlightenment often take special aim at the philosophes and their alleged rationalism, such as when John Gray claims that they all “subscribed to a single project,” namely the ill-conceived endeavor to “supplant the diverse traditions and religious beliefs by which humanity has hitherto been ruled with a new morality whose authority is rational and universal.”Footnote ⁶ It is not only the Enlightenment's critics who take this view, however: scholars who seek to defend other eighteenth-century thinkers and contexts often make an exception for the French Enlightenment, conceding that the philosophes exemplify the worst aspects of the period. Gertrude Himmelfarb, for instance, contends that the French and British Enlightenments constituted separate and fundamentally different “roads to modernity”—the former radical, abstract, foundationalist, and rationalist and the latter sensible, empirical, pluralist, and pragmatic. She aims to encapsulate the French Enlightenment with the phrase “the ideology of reason,” since (she claims) the “exalted mission” of the philosophes was “to make reason the governing principle of society as well as mind, to ‘rationalize,’ as it were, the world.”Footnote ⁷

Even scholars of the French Enlightenment frequently subscribe to this view. In the chapter on France in the widely cited The Enlightenment in National Context, for example, Norman Hampson claims, much as Tocqueville had, that the inability of the philosophes to influence policy in ancien-régime France led them to become radicals rather than reformers—thinkers who approached politics through abstract speculations and “messianic dreams” rather than concrete ideas for practical improvement.Footnote ⁸ Likewise, Maurice Cranston writes that Voltaire and the encyclopédistes “aspired to realize in France the Baconian dream of the sovereignty of reason” via a kind of enlightened monarchy,Footnote ⁹ and Louis Dupré contends that “the philosophes regarded it as their task to emancipate the whole political system from its past tradition and to bring it in conformity with reason.”Footnote ¹⁰ Montesquieu is sometimes singled out as an exception to the rule, but this only serves to underscore the fact that most scholars see the other philosophes as reckless rationalists. Indeed, Montesquieu scholars frequently contrast his moderation and pragmatism with the radicalism and rationalism of the rest of the French Enlightenment, such as when David Carrithers claims that “his rejection of geometrical spirit sets Montesquieu apart from the later, more doctrinaire, reformist philosophes who sought to define a perfect world and get there—whatever the cost.”Footnote ¹¹

Different critics emphasize different elements of this charge, but in general they combine three related allegations. First, they claim that the philosophes believed in the existence of a single ideal form of government or set of laws that can and should be applied universally—the government and laws that accord with “reason” or “nature.” There can be no room for a sensible compromise or a “best in the circumstances,” according to this view, but only a perfect (because perfectly rational) order. Tocqueville, for example, claims not only that the philosophes sought to replace “complicated and traditional customs” with “basic and simple principles, derived from reason,” but that “the political philosophy of the eighteenth century consisted of this single idea.”Footnote ¹² Second, the critics continue, because the philosophes saw traditions, customs, and existing arrangements as little more than burdens to be overcome, they advocated eliminating the old order completely so that society could be rebuilt anew on a more rational basis, much as the French revolutionaries later sought to do. As Oakeshott writes, if “the blank sheet of infinite possibility … has been defaced by the irrational scribblings of tradition-ridden ancestors, then the first task of the Rationalist must be to scrub it clean: as Voltaire remarked, the only way to have good laws is to burn all existing laws and to start afresh.”Footnote ¹³ Finally, the critics contend, the philosophes thought that once rational laws have been put in place, the ultimate result will be inevitable and possibly endless progress in all human realms; the steady application of reason can and will lead to a kind of utopia, or at least the continual improvement of human life. As Berlin states, the philosophes believed that once the comprehensive rational order has been effected, it will “rescue men from political and moral injustice and misery and set them on the path of wisdom, happiness, and virtue.”Footnote ¹⁴

Of the leading thinkers of the French Enlightenment, Voltaire and Diderot might seem at first glance to be among the best exemplars of this tendency toward political rationalism. Voltaire's celebrated catchphrase, “écrasez l'infâme” (crush the infamous), is frequently understood as an uncompromising call to destroy the church or even the old regime altogether, and Gustave Lanson famously claimed over a century ago that Voltaire's Letters Concerning the English Nation “was the first bomb dropped on the ancien régime.”Footnote ¹⁵ Voltaire scholars have often celebrated his political rationalism, such as when Constance Rowe asserts that Voltaire “defined for all thinking people those universal claims of reason which he believed should be enforced by the State.”Footnote ¹⁶ Likewise, in his massive biography of Voltaire, Theodore Besterman portrays him as an almost unqualified believer in “progress through reason,” even going so far as to declare that “nobody could read ten consecutive pages from his pen without realising that belief in perfectibility … was as close to him as his skin.”Footnote ¹⁷ Diderot, for his part, is notorious for declaring his longing for the day when the last king would be strangled with the entrails of the last priest, and the Encyclopedia that he edited is often referred to as a machine de guerre—the war being, of course, against the old regime and all it stood for. Indeed, Anthony Strugnell argues that late in life Diderot adopted “the most uncompromising radicalism” and even that he was “the first effective advocate in the modern world of social and political reconstruction through violent revolution.”Footnote ¹⁸ Geoffrey Bremner, for his part, contends that the fundamental impetus behind all of Diderot's thought was the desire to impose order on the world, to make it rational and unified—in the political sphere just as in the psychological, aesthetic, and ethical spheres.Footnote ¹⁹ The idea that Voltaire and Diderot were political rationalists and advocates of revolution was also advanced by the French revolutionaries themselves, who canonized Voltaire, moving his remains to the Pantheon in 1791, and then embraced Diderot as one of their own in 1796, when, in the midst of the Thermidorian reaction, a number of his previously unpublished writings were released, including the Supplement to Bougainville's Voyage, Jacques the Fatalist, The Nun, and the poem that includes the line about strangling the last king with the entrails of the last priest, entitled Les Eleuthéromanes.Footnote ²⁰

I will argue in this essay, however, that Voltaire and Diderot were not in fact political rationalists in the sense outlined above. Indeed, each element of this charge is dubious as applied to these two thinkers. First of all, neither Voltaire nor Diderot believed in a single “rational” political order that could or should be applied universally; on the contrary, they both insisted that regimes and laws must be suited to a society's particular circumstances. Further, so far from advocating wiping the political slate clean in order to form a wholly new order, Voltaire and Diderot both showed a strong preference for gradual reform, and—despite the later co-option of their writings and reputation by the revolutionaries—they were both lifelong opponents of a general right to revolution. Finally, these two philosophes were neither utopians nor naive optimists: they believed that progress, while possible, is far from inevitable, cannot be endless, and will not be uniform. None of this is to say, of course, that they wholly rejected any role for reason or critical reflection in politics: as we will see, they were liberals and reformers, not apologists for the status quo. But nor were they the radical, naively optimistic, abstract rationalists that they have so often been supposed to be.

I

Voltaire and Diderot were both, broadly speaking, liberals—they both advocated religious toleration, freedom of expression, commerce, legal reforms to limit torture and other inhumane practices, and so on—which is why they both expressed a good deal of admiration for the government and society of eighteenth-century England.Footnote ²¹ Voltaire's embrace of England's liberal mixed regime was not confined to his early Letters Concerning the English Nation (1733), but rather spanned his career. As late as the entry on “Government” in his Questions on the Encyclopedia (1771), we still find him affirming:

Diderot's admiration for England's government and society is not as well known as Voltaire's, but it was no less fervent. Late in life, he went so far as to refer to the English government as

Yet, as we will see in this section, neither Voltaire nor Diderot believed that liberal regimes such as the one found in England were the only rational or legitimate form of government. In fact, they both disavowed the notion of an absolute, universal standard of political legitimacy, arguing instead that regimes and laws must be suited to a society's particular circumstances. There is, for them, simply no such thing as a single “rational” order that could serve as a model for all others.

Throughout his long career and voluminous writings, Voltaire never put forward an ideal regime or set of laws that he conceived of as universally applicable, or even appealed to a universal standard of natural law to judge existing ones.Footnote ²⁴ In some ways this is not particularly surprising, since almost all of his political writings were occasioned by a specific problem or controversy; his ideas for reform were deeply embedded in the circumstances of eighteenth-century France, not abstract speculations meant to be applied to all possible situations. He goes further than this, however, and suggests that no single blueprint could be applicable to all situations—that there is no such thing as a single best regime or set of laws, since “best” is always relative to the character of the people and a host of other factors.Footnote ²⁵ This helps to explain why his political preferences seemed to vary so drastically: he supported a mixed government with a strong Parliament in England; a more popular republic in Holland and Geneva; a strong monarchy in France (in hopes of diminishing the abuses of the clergy, nobility, and parlements); and an even stronger and more centralized one in Frederick's Prussia and Catherine's Russia. No single, “rational” regime or set of laws could possibly fit societies with such varied circumstances and histories. Still further, Voltaire believed that human nature itself undermines the possibility of constructing an ideal or “rational” regime; human beings are sufficiently selfish and foolish that it is impossible to guarantee that any person or group of people will rule well, no matter what institutional arrangements are put in place. As he writes, in a line that encapsulates his political theory as well as any other, “People ask every day whether a republican government is preferable to government by a king. The argument always ends up with agreement that men are very difficult to govern.”Footnote ²⁶

In contrast to his hero John Locke, who argued that illiberal governments could not legitimately lay claim to the allegiance of their citizens—and in fact that absolute monarchies could not properly be considered civil societies at allFootnote ²⁷—Voltaire never posited a universal standard for political legitimacy. Thus, while he generally favored liberal laws, institutions, and practices, he never suggested that all nations must adopt them. This can be seen especially clearly in one of the most frequently criticized aspects of his thought, his penchant for “enlightened despotism.” While Voltaire believed that illiberal regimes often unduly coerce those who live under them, he also held that various factors in the historical development of nations like Prussia and Russia—in particular the need to weaken traditionally privileged bodies such as the nobility and clergy—justified the illiberal rule of Frederick and Catherine.Footnote ²⁸ Moreover, as much as Voltaire admired the English system, he was adamant that it could not be simply duplicated in France or elsewhere. He stresses that the English regime was liberalized only recently, that it was preceded by centuries upon centuries of tyranny, slavery, religious persecution, and civil war, and that it only came about through a confluence of unique factors, ranging from the fact that Britain is an island (which diminished the need for a large standing army) to the obstinate and freedom-loving English “spirit.”Footnote ²⁹ Thus, immediately after the encomium of England quoted above, he rhetorically asks, “Why then are these laws not followed in other countries? Is that not the same as asking why coconuts flourish in India, but do not do very well in Rome?”Footnote ³⁰ As Peter Gay writes:

In short, Voltaire's liberalism was far more pragmatic than rationalist.Footnote ³²

Like Voltaire, Diderot never outlined an ideal regime that could serve as a model for all others, and he generally refrained from appealing to a standard of natural law in judging existing ones.Footnote ³³ He too stressed that circumstances are decisive in determining which laws should be adopted, and thus he sought to discourage attempts at general reform based on abstract, “rational” conceptions of political right. For instance, in his commentary on Catherine's supposedly enlightened “Code” for Russia, he warns her, “I do not know if the Code can ever be as short, simple and clear a work as you imagine.”Footnote ³⁴ Even if a particular law is “good and useful in one circumstance,” it is often “bad and harmful in another,” and thus wise laws and political decisions require a detailed knowledge of a society's complex history, traditions, and other circumstances.Footnote ³⁵ As Sankar Muthu notes, this is one of the grounds on which Diderot attacked colonialism: “imperial rule over far-flung territories is unlikely to yield just political institutions; foreigners will be unlikely to know the local circumstances better than indigenous peoples themselves. Moreover, no universally valid, privileged political ideology exists that could guide a would-be conqueror.”Footnote ³⁶ And, just as in the case of Voltaire, there has been little consensus about Diderot's ultimate political preferences: he is sometimes depicted as a proponent of constitutional monarchy, sometimes as a republican or democrat, and sometimes even (in light of his ambivalent relationship with Catherine) as an advocate of “enlightened despotism.”Footnote ³⁷ Once again, no regime is simply the “best” or applicable everywhere and always.

While Diderot went much further than Voltaire in condemning both the absolutism of the French monarchy and the “enlightened” despotisms of Frederick and Catherine, he too refrained from making blanket statements about what is universally necessary for a state to obtain political legitimacy.Footnote ³⁸ He recognized that appeals to abstract standards of right are likely to do far more harm than good, especially because the stability of a government and its laws depends so heavily on public opinion, which in turn depends more on custom and tradition than on abstract reason.Footnote ³⁹ Further, Diderot too acknowledged the need to accept imperfections in politics. When Louis XV stripped the Parisian parlement of its powers in 1771, Diderot condemned him for doing so, despite the fact that (as he explicitly admits) the parlement had been Gothic in its views and customs, opposed to all reform, intolerant, and a foe of the philosophes; it was still preferable to endure these ills rather than to eliminate the parlement's powers, he maintained, since it was one of the few bodies that prevented the king from exercising absolute and arbitrary power.Footnote ⁴⁰ Nor did Diderot think, any more than did Voltaire, that England's model could or should be applied universally; even in the tribute quoted at the beginning of this section, he notes that the English model is “if not perfect or free of faults … at least the most well-suited to the condition of the country.”Footnote ⁴¹ Like Voltaire, then, Diderot not only refused to put forward any single ideal regime, but also understood the real-world model that he most often lauded to be importantly flawed and limited in applicability.

In short, Voltaire and Diderot both consistently eschewed abstract, “rational” political blueprints, believing that such blueprints necessarily ignore the diversity of circumstances and the complexity of human life. Neither of them posited an ideal regime that could serve as a model for all others, and they both emphasized the importance of context in determining which laws a society should adopt. All of this, of course, undercuts the foundations on which any charge of political rationalism must rest—since there is, for them, simply no “rational” order to appeal to—but it still might be claimed that Voltaire and Diderot were radicals or revolutionaries, thinkers who wanted to (as they themselves seem to suggest) burn laws and strangle kings in order to eliminate the injustices that they saw all around them. As we will see in the following section, however, this part of the charge is doubtful as well, in spite of what some of their rhetoric, ripped from its context, might seem to imply.

II

While neither Voltaire nor Diderot believed in a single “rational” set of laws that could be universally applied, both of them hoped that France would move in a broadly liberal direction—that different religious beliefs and practices would come to be tolerated, free expression permitted, commerce promoted, more humane criminal laws adopted, and the like. Yet, as we will see in this section, they did not insist that such changes must be made all at once, or that the social, political, and legal slate must be wiped clean in order to make room for a more liberal order. On the contrary, they advocated piecemeal reform and consistently opposed the “spirit of system” that leads people to try to overthrow the old order with the aim of imposing abstract, “rational” ideals on society from above. Once again, they were certainly not mere advocates of the status quo; they did want to “change men's common way of thinking,”Footnote ⁴² to use Diderot's famous line from the Encyclopedia, and to move their societies in a more liberal and humane direction. But their outlook would be better categorized as reformist, gradualist, or meliorist than as rationalist, radical, or revolutionary.

It is not hard to understand why scholars have so often painted Voltaire as a political rationalist, because a number of his bolder claims, removed from their proper context, do seem to point in this direction. For instance, he writes in his Treatise on Tolerance that “past eras must be treated as if they had never been. One must always start from the present, from the point to which nations have thus far evolved.”Footnote ⁴³ And, in the passage that Oakeshott singles out, he asserts in his Philosophical Dictionary that “if you want to have good laws, burn what you have, and create new ones.”Footnote ⁴⁴ Yet the context of these kinds of passages generally belies a purely rationalist reading, and often even points toward the opposite, the importance of historical context and gradual reform. The line from the Treatise on Tolerance, for instance, appears in a chapter entitled “To show how tolerance may be permitted,” which is addressed to political and ecclesiastical legislators, urging them to see that even if religious toleration may have proven difficult to institute in the past, the obstacles to such a policy no longer remain. Contrary to what the quoted passage itself might seem to imply, then, the historical context is in fact crucial to Voltaire's argument: his claim is that France's present legislators need not be unduly influenced by past conflicts between Catholics and Protestants, given that other nations have enjoyed relative peace after introducing religious toleration and that “all educated persons nowadays” view religious enthusiasm with derision.Footnote ⁴⁵ In other words, his broader point is less that we must always ignore the past than that it is no longer appropriate, in mid-eighteenth-century France, to persecute people on the basis of religion, just as it is no longer appropriate to punish people for witchcraft.Footnote ⁴⁶ A change in circumstances allows or justifies, and sometimes even requires, a change in policy—a sentiment that Oakeshott himself embraces.Footnote ⁴⁷

Similarly, the point of the line from the Philosophical Dictionary about burning existing laws seems to be to emphasize the difficulty of establishing good laws rather than to actually advocate wiping the legal slate clean. This line comes in the entry on “Laws,” which stresses the great arbitrariness and inconsistency of laws, both within and between nations, and the great cruelty that is frequently inflicted in the name of the law. The immediate context is a comparison of these irregular laws with irregular city streets, and the burning of the laws with the Great Fire of London: “London only became worth living in since it was reduced to ashes. Since that time, its streets have been widened and straightened. Being burnt down made a city out of London. If you want to have good laws, burn what you have, and create new ones.”Footnote ⁴⁸ Yet Voltaire is not arguing that all existing laws should be eliminated, any more than he is advocating deliberately burning down the whole of Paris. After all, the entry as a whole shows him to be quite pessimistic about the possibility of devising and implementing a good set of laws: time and again he points to the influence of particular and short-term interests, ignorance, and superstition on legal codes.Footnote ⁴⁹ And, as we have seen, he makes no effort—in this entry or elsewhere—to devise a perfect, uniform set of laws, or even to appeal to a universal standard of natural law in judging existing ones. Voltaire believed that laws could be made better—if, for instance, they were reformed in a more humanitarian direction along the lines suggested by BeccariaFootnote ⁵⁰—but certainly not perfect. To suggest that Voltaire was actually in favor of devising a new set of laws from scratch would seem to drastically overestimate his expectations from politics.

This more realistic or chastened reading of Voltaire is reinforced by his consistent opposition to a general right to revolution and to the spirit of system throughout his career. As David Williams writes, despite the fact that he was later apotheosized by the French revolutionaries, “Voltaire was never an advocate of revolution. The upheavals of 1789 would have appalled him, the power of the mob terrifying him as much, if not more, than that of autocrats.”Footnote ⁵¹ Voltaire's hesitations about extending political power to the masses are rightly derided today, but they do underline the fact that in French politics he was an advocate of the thèse royale—the idea that the nobility and priests were the true despots, and that the only effectual means of curbing their power would be a reforming king with broad, centralized authority—rather than the inventor of a new thèse bourgeoise, let alone a thèse sans-culotte. Voltaire was far too much a realist to suppose that radical changes—even if based on sound principles—would always turn out for the best. While there may be a few ostensibly rationalist moments in his writings, then, his general approach is one of pragmatism and reform rather than ignoring the past and wiping the slate clean. “His tactics were those of attrition, not of devastation, of practical gradualism, not of doctrinaire violence,” writes William Bottiglia. “It is true that he fought with a fanatical zeal, yet his ends were moderate. He believed in small steps rather than great leaps because he understood the difficulties and the risks of social change and did not want a whole way of life to be suddenly engulfed in a diluvial disaster.”Footnote ⁵² Thus Gustave Lanson, the scholar who proclaimed that the Letters Concerning the English Nation was the first bomb dropped on the ancien régime, also asserts that “Voltaire was, beyond any doubt, a conservative,” or rather “a conservative in the manner of any true liberal.”Footnote ⁵³

What, finally, of Voltaire's famous catchphrase, “écrasez l'infâme”? There has been a good deal of scholarly dispute about what exactly he meant by l'infâme; it is generally accepted that he was referring above all to religious intolerance, repression, and fanaticism, but at times this catchphrase has also been interpreted as a call to arms, to tear down the old order in its entirety. However, not only was Voltaire adamant about preserving the French monarchy, he also never advocated the elimination of the church, nor even a complete separation of church and state (as Diderot did). Indeed, at one point—in a letter to a fellow philosophe, d'Alembert, no less—Voltaire equates crushing l'infâme with nothing more than getting France to the point that England had already reached: “I would like you to crush l'infâme, that is the great point. It must be reduced to the state where it is in England. … That is the greatest service one can render to mankind.”Footnote ⁵⁴ And England, it will be recalled, had an established church, as Voltaire himself carefully notes elsewhere.Footnote ⁵⁵ In fact, Voltaire explicitly states in his Treatise on Tolerance that “I do not say that all those who profess a different religion from that of the reigning prince should share in the places and honors available to those who are of the prevailing religion. In England, Roman Catholics are considered as belonging to the party of the Pretender, and are therefore denied office; they even pay double tax; yet they still enjoy all the other privileges of the citizen.”Footnote ⁵⁶ Voltaire did steadfastly advocate religious toleration and rail against the excessive economic and political power of the clergy in eighteenth-century France, but he was far from exhorting people to crush the church or the old order altogether.

Diderot was far more cautious than Voltaire with regard to rhetoric about burning all laws or wiping the slate clean.Footnote ⁵⁷ As we have seen, he frequently sought to discourage attempts at general reform, such as when he cautioned Catherine that social and political changes must be made in accordance with the evolving desires of the people and the development of Russian civilization. This is a recurring theme of Diderot's works. In one of his contributions to the abbé Raynal's History of the Two Indies, he offers a word of caution that could have come from Burke's or Oakeshott's pen: “The state is a very complicated machine which one can neither assemble nor set in motion without knowing all the pieces. You cannot press nor loosen a single one without disturbing all the others. … All innovations should be gradual, born from need, inspired by a kind of public clamor, or at least in accord with general wishes. To create or destroy suddenly is to corrupt the good and make the evil worse.”Footnote ⁵⁸ Diderot certainly did not oppose all innovation, but his message is generally one of moderation: existing institutions and arrangements should not be lightly tampered with, especially on the basis of some abstract conception of a perfect order. Hence, Lester Crocker summarizes Diderot's “overall view” by stating that he “is a man of the Enlightenment, a meliorist, and a reformer within the limits of the possible.”Footnote ⁵⁹

All of that said, Diderot did sometimes advocate overthrowing a particular government or ruler—especially colonial rulers—and late in life he even seemed to condone tyrannicide in exceptional cases. Many of Diderot's works condemn, in extraordinarily harsh language, the violence and injustices perpetrated by the European powers against their colonies in the Americas, Asia, and Africa.Footnote ⁶⁰ In some of his contributions to the History of the Two Indies, he goes so far as to call on indigenous peoples to revolt against the colonists, arguing that it is necessary to speak in the only language the colonists seem to understand: violence. To the Hottentots who faced incursions from the Dutch, for instance, he urges, “Do not address them with representations of justice, which they will not listen to, but speak to them with your arrows. … Take up your axes, bend your bows, and send a shower of poisoned darts against these strangers. May there not be one of them remaining to convey to his countrymen the news of their disaster!”Footnote ⁶¹ He also applauds the American colonial rebellion and exhorts them to remain strong in their fight against oppression.Footnote ⁶² Still further, on rare occasions Diderot also appears to hint at the legitimacy of tyrannicide, praising the likes of Brutus and applauding the trial and execution of Charles I by Cromwell and his compatriots.Footnote ⁶³ Far more often, however, he advocates simply speaking out against abuses of power. In his diatribe against the authoritarianism of Frederick, Diderot stops short of sanctioning resistance, instead only arguing for freedom to criticize the government. In response to Frederick's insistence that a good citizen must respect the government under which he lives, Diderot writes:

This line between active resistance and speaking out against bad laws, with the latter justifiable and the former not, occurs frequently throughout Diderot's mature writings.Footnote ⁶⁵

Further, even in the instances in which Diderot did advocate colonial rebellion or hint at the legitimacy of tyrannicide, he never envisioned the institution of a wholly new order; brief violence may be necessary to eradicate a glaring injustice, but Diderot was insistent that attempting to overturn all existing arrangements would lead to nothing but disaster. In the Supplement to Bougainville's Voyage, for instance, the character B (who seems more or less to speak for Diderot throughout) insists, “We must speak out against senseless laws until they're reformed and, in the meanwhile, abide by them. Anyone who on the strength of his own personal authority violates a bad law thereby authorizes everyone else to violate the good. Less harm is suffered in being mad among madmen than in being wise on one's own.”Footnote ⁶⁶ And, as John Hope Mason has been at pains to point out, even in Diderot's contributions to the History of the Two Indies, many of which are full of impassioned protests against the oppression of tyrants and colonizers, there is still “no vision of a new order, no call for or belief in popular or particular revolt in any European context.”Footnote ⁶⁷ Indeed, at one point in this work Diderot warns:

Or again: “The chimera of equality is the most dangerous of all beliefs in a civilized society. To preach this system to the people is not to recall its rights, it is to invite the people to murder and pillage; it is to unchain domestic animals and transform them into wild beasts.”Footnote ⁶⁹ In all, it would be hard to argue that Diderot advocated overturning France's ancien régime—or any order, for that matter—in its entirety.

The idea that Diderot was not an advocate of eliminating the old order seems to be contradicted, of course, by his most infamous line, his alleged proclamation that “man will never be free until the last king is strangled with the entrails of the last priest.” This is, however, not only a misquotation, but a misquotation of a dubious source: the line derives not from a serious philosophical work or even a political pamphlet, but from a poem that was written as a kind of New Year's Eve joke. Every New Year, Diderot and some of his compatriots would gather at the Baron d'Holbach's house in Paris for a feast, and whoever found a bean in his cake would be named “King of the Revels.” In 1772, when Diderot had been selected (perhaps by design) for the third straight year, he composed a playful ode abdicating his throne and passing judgment on tyrants, in part provoked by the fact that Louis XV had just stripped the Parisian parlement of its judicial powers.Footnote ⁷⁰ It was in this mock production of calculated hyperbole that he has one of the characters say,

These lines are, however, not even Diderot's own; rather, they are a close paraphrase of Jean Meslier's Testament, which was written decades before Robespierre and his compatriots were even born (no later than 1729).Footnote ⁷² Thus, these infamous lines are in fact someone else's words, put in the mouth of a character in a poem written as an elaborate joke; to suggest that the revolutionary sentiment contained in them is an accurate reflection of Diderot's thought, particularly when it runs so directly against the grain of his more serious writings, seems misleading indeed.

It is, of course, impossible to resolve here the much-debated issue of the extent to which the philosophes “caused” the French Revolution—as if it were possible to weigh the impact of, say, the Encyclopedia against that of the price of bread in Parisian shops.Footnote ⁷³ What can be said with some certainty, however, is that Voltaire and Diderot themselves opposed, on principle, the idea of total revolution, especially based on an abstract conception of a perfect, “rational” order. As Robert Wokler writes, in a statement that clearly applies to Voltaire and Diderot, among many others:

It is true that Voltaire and Diderot sought to undermine some of the intellectual pillars on which the old regime rested, from the divine right of kings to the legitimacy of the church's extensive temporal powers. Further, all of the reforms that they advocated, taken together, would indeed have resulted in a largely new political order. As we have seen in this section, however, they sought to institute these liberal reforms gradually, not to overthrow the old regime all at once. And, as we will see in the following section, they did not believe that these changes were inevitable, or that they would lead to endless progress if they were instituted; these thinkers were far from being the naive optimists and starry-eyed utopians that they are sometimes thought to have been.

III

The third and final element of the charge of political rationalism, namely, that the philosophes believed that the steady application of reason can and will lead to an ideal society or to nearly endless progress, is perhaps the most dubious of all as applied to Voltaire and Diderot: both of these thinkers were deeply and manifestly—one wants to say instinctually—antiutopian. Neither of them believed that progress toward the liberal political practices and institutions they favored was in any way inevitable or could possibly be endless or uniform, and while they believed that these practices and institutions would improve people's lives in important ways if they were introduced, they did not believe that any political order could solve all human problems. The notion of progress as an intrinsic law of history—an idea that can be found in the writings of other philosophes such as Turgot and Condorcet, although it truly came into its own only with the rise of German Idealism—is utterly foreign to the thought of Voltaire and Diderot. They were both far too realistic, too alive to the drawbacks of even their relatively enlightened age, to be dupes of the sort of faith in the “historical process” that came to enthrall later generations of thinkers. While they believed that some scientific, economic, political, and even moral improvements were possible, and in fact had already occurred in eighteenth-century Europe, they persistently mocked naive optimism and ideas of inevitable and endless progress.Footnote ⁷⁵

It is truly remarkable that naive optimism is so often attributed to an era whose most famous author's most famous book is Candide; the Enlightenment is thought to be Panglossian when it was Voltaire who invented this term of derision.Footnote ⁷⁶ The basic facts of Voltaire's story are well known: the protagonist is a disciple of Doctor Pangloss, who is himself a disciple of Leibniz and his philosophical optimism. From the outset, however, Candide endures a long series of unrelenting misfortunes that make it impossible for him to continue to believe that ours is “the best of all possible worlds”; each turn of the story further undermines Pangloss's optimistic outlook. Through this story Voltaire impresses upon the reader, as no philosophical reasoning could, that naive optimism is unwarranted and foolish.Footnote ⁷⁷ As Roger Pearson writes, “rape, pillage, murder, massacre, butchery, religious intolerance and abuse, torture, hanging, storm, shipwreck, earthquake, disease, cannibalism, prostitution, political oppression and instability: all is well.”Footnote ⁷⁸ And the story of Candide is no anomaly: Voltaire ridiculed optimism in a myriad of other works as well, perhaps most famously in his poem on the Lisbon earthquake and the entry in his Philosophical Dictionary entitled “All is well.”Footnote ⁷⁹

Of course, in the final pages of Candide the title character learns to ward off boredom, vice, and poverty and to find relative contentment through the working of his land or cultivation of his garden.Footnote ⁸⁰ As David Wootton notes, judging by the conclusion it seems that Voltaire advocates replacing Pangloss's optimism (the claim that this is the best of all possible worlds) not with outright pessimism (the claim that it is the worst of all worlds) but rather with meliorism, or the claim that the world can be made better.Footnote ⁸¹ Yet a better world is only a possible, not a necessary outcome, and one that human beings must create for themselves, not one that is written into History or preordained by God. And even this possibility seems to be more an individual affair than a societal or global one: Voltaire gives little indication that a perfect society—perhaps even a good one—is within human reach. From his garden Candide can watch boats carting people into exile, and others carrying severed and stuffed heads to be presented to the sultan.Footnote ⁸² Even El Dorado, the fairy-tale utopia that he discovered in the New World, had ultimately proven insufficiently enticing, and he continued on his travels after a relatively short stay there.Footnote ⁸³ In the end, Candide's meliorism seems to consist as much in an escape from the world's troubles as in a solution to them.Footnote ⁸⁴

This somewhat gloomy view of the world is in harmony with Voltaire's historical works, many of which are filled with repeated statements that (as a character in one of his stories puts it) “history is but a tableau of every crime and catastrophe.”Footnote ⁸⁵ Almost the entire “Recapitulation” of Voltaire's Essay on the Mores and Spirit of Nations, for example, is dedicated to showing that “in general all of history is a collection of crimes, follies, and misfortunes, among which one sees a few virtues and a few happy times, just as one discovers a few scattered houses in a barren desert.”Footnote ⁸⁶ Such rhetorical flourishes are slightly misleading, however, because Voltaire did think that the world had improved in important respects. For instance, in The Age of Louis XIV, he describes in detail the way in which the conditions of mid-eighteenth-century France were unquestionably an improvement over those of the same nation little more than a century earlier, when “the streets of Paris, narrow, badly paved and covered with filth, were overrun with thieves”; when the “spirit of discord and faction … pervaded every community in the kingdom”; and when “the French nation was steeped in ignorance” to the point where people believed unreservedly in astrology, sorcery, and exorcism.Footnote ⁸⁷ Eighteenth-century France may not have shined in the arts to the degree that it had under Louis XIV, Voltaire concedes, but the lives of most people were far more tolerable. Yet he did not believe that this progress had been inevitable, or that further progress would necessarily follow. (In the entry on “Politics” in the Questions on the Encyclopedia, with tongue only partly in cheek, he looks forward to a day “in another ten or twelve centuries, when men are more enlightened.”Footnote ⁸⁸) Thus, even John Gray—no admirer of Voltaire—concedes that “he was too alive to the quiddities of human circumstances and too alert to the sufferings of individual human beings to subscribe unambiguously to any grand scheme of human progress.”Footnote ⁸⁹

In fact, one of the main purposes of Voltaire's historical works was to refute the idea that history is teleological or heading toward some perfect end point. Many of the best-known historical works of the eighteenth and preceding centuries—works like Bossuet's Universal History, which drew Voltaire's particular ire—envisioned history as a divinely guided or controlled process, a succession of events that were dictated by God either through miraculous intervention or (more often) through His power over the hearts and minds of human beings. In deliberate contrast to this view, Voltaire points time and again to the utter unpredictability of events and the important role often played by seemingly minor causes. In The Age of Louis XIV he goes so far as to attribute the fall of the Duke of Marlborough, the turning out of the Whig party, and the end of the War of the Spanish Succession to the personal affronts shown by the Duchess of Marlborough when she refused to give Queen Anne a pair of gloves that she desired and spilled some water on the dress of one of the Queen's favorites: “such trifles changed the face of Europe,” he writes.Footnote ⁹⁰ In short, Voltaire believed that even if humanity had made real progress in certain realms, this progress was not, and could not be, inevitable, endless, or all-embracing.

Diderot did not devote nearly the amount of attention to history that Voltaire did, but it is abundantly clear that he was far from subscribing to any simple notion of progress. Indeed, at times he appears to decry the onslaught of civilization in a manner reminiscent of Rousseau, particularly in the Supplement to Bougainville's Voyage, where he seems to depict the Tahitians as natural, innocent, contented, and free, in stark contrast to the Europeans, who are artificial, corrupt, miserable, and enslaved to morality, religion, and custom.Footnote ⁹¹ It is fairly clear, however, that Diderot did not ultimately believe that primitive societies were as idyllic as this narrative seems to imply at first glance. Elsewhere, he takes careful note of “the hatred which one tribe of primitive men bears against another, their hard life on the edge of subsistence, the persistence of their wars,” and so on.Footnote ⁹² Moreover, the reader learns toward the end of the Supplement that even Diderot's (by and large fictitious) Tahitians were quite calculating and ruthless in their own way.Footnote ⁹³ Diderot's primary aim was surely to use Tahiti as a foil with which to point out the flaws of the Europe of his day rather than to demonstrate the actual superiority of the primitive way of life. Elsewhere, he forcefully affirms that eighteenth-century Europe had in fact made important advances: “Whatever Jean-Jacques Rousseau and the fanatical enemies of the progress of the human spirit may say,” he proclaims, “it is difficult to read the history of the barbarous centuries in the life of any people without congratulating oneself upon being born in an enlightened century and in a civilized nation.”Footnote ⁹⁴

Yet whatever advantages “enlightened” and “civilized” Europe may have had, Diderot did not believe that the gains that had been made were inevitable, or that future progress could be indefinite. Rather, he seems to have subscribed to a cyclical view of history, according to which all societies go through periodic stages of youth, growth, maturity, and decline. He claims that all societies

Elsewhere, he reiterates that “the fate which rules the world wills that everything will pass away. The happiest state of an individual and a nation has its end. Everything carries within itself a hidden germ of destruction.”Footnote ⁹⁶ Thus, it seems extraordinarily doubtful that the “enlightened” and “civilized” nations of Europe will always remain so. Even in the Encyclopedia entry in which he famously lauds the “march of the human spirit” that occurs when useful knowledge is disseminated and everyday life is made easier, Diderot also insists that all things have their limits and that progress is always eventually brought to a halt.Footnote ⁹⁷ He did seem to have some hope that the New World, which was still in its youth, could carry on the torch of liberty and civilization, but even his high hopes for the American colonies were tinged with an awareness that nothing lasts forever: “May they postpone, at least for a few centuries, the decree pronounced against all earthly things: the decree which condemns them to have their birth, their time of vigor, their decrepitude, and their end!”Footnote ⁹⁸

Nor did Diderot believe that Europe had experienced progress in all respects. Their achievements in developing “civilization” and spreading “enlightenment,” for example, were not necessarily accompanied by similar advances in morality, toleration, or compassion. In a letter to Mme de Maux, his mistress for a brief time, he wonders, “Do you think that men ever become better? It is certain that we are not as barbarous as our fathers. We are more enlightened. Are we better? That is another thing.”Footnote ⁹⁹ In fact, Diderot seems to have harbored serious doubts that simultaneous progress in all realms was a real possibility. In the Encyclopedia, he attempts to split the difference between Hobbes's claim that people are naturally hostile and must be restrained by law and force, on the one hand, and Rousseau's claim that people are naturally good and are corrupted by such “civilizing” mechanisms, on the other, asserting that “man's goodness and wickedness remain constant, his happiness and suffering circumscribed by limits he cannot breach. All the benefits of human industry are balanced by evils, all natural evils by good works.”Footnote ¹⁰⁰ In other words, no society can overcome the very definite limits set by human nature, and no progress will be free of accompanying faults. Thus, Diderot laments elsewhere in the Encyclopedia that “even though the world is getting older, it is not changing; individual man may be improving, but the mass of mankind is getting neither better nor worse.”Footnote ¹⁰¹

In short, Voltaire and Diderot were far from being the naive optimists or believers in inevitable and endless progress that the philosophes as a group are so often claimed to have been. They saw most of history as a story of oppression and misery, and it was this bleak view of the past that led to their belief in “progress,” such as it was. In other words, they did believe in progress in the sense that they thought the Europe of their time constituted an improvement in many ways over what had come before it, but they did not believe that there was any kind of supernatural agency, transcendent design, or Hegelian dialectic that meant that it had to be better than what came before it, or that the future would be better still. They were well aware that throughout history civilizations had come and gone, and would likely persist in doing so; that even the progress that had been made in eighteenth-century Europe had generally been a mixed bag, with all of the advances and improvements complemented by important drawbacks and limitations; and that there is no reason to think that progress will continue indefinitely, or that a perfect society will ever be within human reach.