The Friendship between Denis Diderot and Catherine The Great

On July 30, 1767, Muscovites awoke to find Don Cossacks striding past the Kremlin and knots of Kalmyks from the Caucasian steppes massing outside the Cathedral of the Assumption. In normal times, they would have fled. But that particular day was anything but a normal time. Moscow was besieged, but not by marauding tribes. Instead, more than five hundred Russian subjects, Christians and non-Christians, town and village dwellers, aristocrats and artisans, had descended on Moscow not to pillage, but to ponder and propose a new code of law. The nature of this mission was as unprecedented as the individual who unfurled it: a young woman who five years earlier had claimed the Russian throne after overthrowing her husband, Tsar Peter III, who succumbed shortly thereafter — all too conveniently and none too believably — to an attack of hemorrhoids.

Today marks the 250th anniversary of the Legislative Commission convened by the Empress Catherine the Great. (“Great,” incidentally, is a title she humbly refused when it was offered by the Commission — though her humility takes a hit upon learning that she had also instructed the Commission to offer the title.) Granted, the Legislative Commission does not seem as dramatic an event as, say, the Russian Revolution, whose anniversary is also being marked this year. And yet, while there is no Lenin haranguing supporters at the Finland Station or Bolshevik soldiers storming the Winter Palace, the Commission ripples with great drama and tragedy. More importantly, the event raises hard questions about issues as relevant today as they were 250 years ago — questions regarding the relationships between the ideal and the real, morality and policy, philosophers and kings. What Catherine hoped to do and what she did measures the perhaps inevitable gap between thinkers who propose and rulers who dispose.

Born into a family of obscure German aristocrats, delivered to St. Petersburg at the age of 14, and married in great pomp to the feckless heir to the Russian throne, Catherine found herself alone. While Peter (as the story goes) drilled his military dolls and hanged rats from toy gallows, Catherine turned for solace to, of all people, the French philosophes. Shortly after her wedding, she picked up, if not for very long, Montesquieu’s Considerations on the Causes of the Greatness of the Romans and Their Decline. “When I began to read, it led me to reflect, but I could not read it straight through because it made me yawn.” Declaring it was a “fine book,” the teenager then “tossed it aside to continue getting dressed.”

The book was tossed, but its lessons were not lost. Reflecting on the moral nature of Rome’s greatness, Montesquieu underscores the vital bundle of traits that ensured Rome’s ascension: the embrace of law, cult of self-sacrifice, love of country, and dedication to principles of the res publica. Crucially, Montesquieu also emphasizes the place of war: a nation’s greatness is measured, at least in part, by its military conquests. Only when wars became the means for ambitious commanders to achieve personal power did Rome begin its long decline and fall.

Two decades later, Catherine seems to have recalled the book’s general tenor. The flame of patriotism and foundations of law, she understood, were essential to a nation’s greatness. By the same token, love of one’s country entailed the knowledge of that country’s history and institutions, and love of the law required that a body of laws first exist. This was not the case in the country she now commanded. Instead, there was a chaotic sprawl of conflicting and confusing decrees, a man-made mire more daunting than the miasmal swamps Peter the Great had drained — at the cost of tens of thousands of lives — and on which his city now stood. It was thus with great anticipation that, in 1767, Catherine announced the creation of a Legislative Commission in order to impose order where there was none, using as its guide the Velikiy Nakaz, or Great Instruction, that Catherine had compiled during the previous two years.

Once again, Catherine turned to Montesquieu, this time to his classic The Spirit of the Laws. But she turned to him with scissors and paste in her royal hand. Of the 526 articles forming the first part of the Nakaz, more than half — 294, to be exact — are lifted, word for word, from Montesquieu’s work. Slightly more than a hundred other articles are culled from the Italian thinker Cesare Beccaria’s landmark Of Crimes and Punishments, which had been published in French translation. Unlike the current raft of Russian officials, including President Vladimir Putin, who have been accused of plagiarizing the work of others for their dissertations, Catherine made no pretense that her Nakaz was original. As she happily confessed, “For the sake of my empire, I have robbed Montesquieu without mentioning him by name. If he sees my work from the next world, I hope he will pardon me this plagiarism for the good of 20 million people. He loved humanity too well to take offense.” (Putin has yet to confess that he happily stole from a 1978 American textbook, Strategic Planning and Public Policy, for the good of his career, if not his fellow Russians.)

However Montesquieu felt in the next world, the iconic figure of the Enlightenment, Voltaire, insisted that the Nakaz flowed directly from Catherine’s genius. Upon rereading its French translation, the author of Candide gushed to the empress that it was “the century’s most beautiful monument” and more glorious than 10 military victories against the Ottoman Empire. Why? Because the “Minerva of the North” — one of his many monikers for Catherine — had not personally slaughtered the “Turks with her own hand.” But that “beautiful hand had written the Nakaz” all by itself.

Hard though it is to digest Voltaire’s obsequiousness, it is harder to dispute the reasons for his praise. Never before had a ruler — one, moreover, who had recently come to power in unorthodox circumstances and confronted a staggering array of economic, social, and geo-political challenges — marshaled the discipline and dedication to research and write a document, containing 22 chapters and 655 clauses, to found the nation’s legal code. The heavy burden she imposed on herself took its toll; during the two years she compiled the work, she suffered from migraine headaches. Yet the result, as Catherine’s biographer Isabel de Madariaga rightly claims, was “one of the most remarkable political treatises ever compiled and published by a reigning sovereign in modern times.”

Catherine unabashedly took the words of Enlightenment thinkers, but she also took these thinkers as they wished to be taken: as shapers of public opinion, progressive ideals, and public policy. The trick, however, was that the Russian public was utterly unlike the publics in Western countries. An empire peopled by an illiterate and indentured peasantry, an embryonic civil society, a skeletal professional class, and a rustic and reactionary aristocracy was an unlikely test case for enlightened principles of governance. No less daunting was the sheer size of Catherine’s empire. Neither a monarchy (as in Prussia) nor limited monarchy (as with Great Britain) — two less extreme points on Montesquieu’s spectrum of governments — could hope to rule so extensive a nation. It took a despot, and not a monarch, to impose progress.

Yet Catherine recoiled from the title “despot.” Shortly before taking the throne, she wrote in her journal: “Liberty, the soul of all things, without you everything is dead. I want the laws to be obeyed, but I don’t want slaves.” Tellingly, in the Nakaz’s opening line, she announces that Russia is a European state. Distancing her country from the shame attached to “Asiatic despotism,” she aims to divorce herself from the disgrace of being a despot. While despotism may work for the Ottomans or Persians, Catherine insists, it ill-suits a European nation like her own.

Here was the rub: Catherine agreed with Montesquieu’s insight that good laws and good institutions were equally crucial to prevent rulers from running roughshod over their peoples. Yet good institutions, rooted in civil society and independent of the throne, were rare in a world of bound subjects and slave labor, held together by fear of the knout and submission to tradition. And so, while Catherine scrambled to banish the bad odor of despotism, she believed she had no choice but to maintain her despotic powers. She saw that to rule Russia — to continue the work of Peter and introduce reforms that would benefit its people — required her to be their despot.

This tension ripples through the Nakaz. It appeals to a world that ought to be, while accepting the world as it is. Political liberty, Catherine noted before becoming Empress, requires that citizens “find themselves under the protection of the law, which causes one citizen not to fear the other.” On the other hand, it is good to fear one’s ruler. Yes, laws “must be sacred to a monarch, for they remain forever while subjects and kings disappear.” But, in a sleight-of-hand, she then concludes that it is really the state — which does not rhyme with ruler — that “has every interest in keeping strictly to the laws.”

When it came to the matter of crime and punishment, however, Catherine proved to be more enlightened than not only her contemporaries, but also the rulers in Russia and the United States in our own day. Scarcely had she ascended to the throne when she sent a generous amount of money to the family of Jean Calas, a victim of religious fanaticism in France. In 1761, the Catholic parlement in Calas’s native city of Toulouse had charged the Protestant merchant with the murder of his son. The cause, they alleged, was that Calas senior had been enraged by his son’s decision to convert to Catholicism. Because their case was based entirely on prejudice and innuendo, the city and church authorities, desperate for a confession, painstakingly tortured Calas in a public ceremony. Finally, an exasperated executioner garroted the unjustly condemned man, broken on the wheel but insisting on his innocence, and burned his body.

Soon after learning of the event, Voltaire launched a campaign to reverse the court’s charges against Calas and revile those responsible for them. It was a decision requiring great valor and verve, the latter of which Voltaire generally had much more of than the former. This time, though, he summoned both. In his many months of pamphleteering and corresponding, he galvanized public opinion and goaded royal officials with a single message: Écrasez l’infâme. In his plea to stamp out the infamous thing, by which Voltaire meant religious fanaticism and superstition, Voltaire achieved his goal: the Toulouse parlement’s decision was reversed, Calas’s innocence was restored, and his family, which had been forced to flee their home, was reunited.

Voltaire’s campaign enthralled Catherine. After Catherine sent the generous financial gift to the Calas family, it evoked, all too predictably, Voltaire’s obsequious praise: the philosophes, he declared, “are at your feet.” But it was also heartfelt: the Calas Affair had deeply disturbed Catherine’s sense of justice. There was much sincerity when she told Voltaire that the Calas family and the world owed him everything: “You have combated the massed enemies of mankind: superstition, fanaticism, ignorance, intrigue, evil judges, and the abuse of power.”

The Nakaz was Catherine’s means to join forces with Voltaire. She declared that punishment should be preventive, not retributive, and was especially unforgiving on the use of torture. In a proposition disputed by our own aspiring despot, she declared: “The innocent ought not to be tortured; and in the eyes of the law, every person is innocent whose crime is not yet proved.” Not only must torture never be used to secure a confession of guilt, but it was also impermissible as punishment. Its usage, she affirms, “is contrary to all the Dictates of Nature and Reason; even Mankind itself cries out against it, and demands loudly its total Abolition.”

On the eve of the Commission’s opening, the British envoy to Russia reported that everyone could “think and talk of nothing else, and in seeing the representatives of several nations, so very different both as to dress, customs, and religion […] assemble in their capital, they are apt to conclude that they are now the wisest, the happiest, and the most powerful nation in the universe.” In a letter to Voltaire, Catherine echoed this upbeat account: “I believe you would enjoy this assembly, where an Orthodox Christian, heretic, and Muslim listen to a heathen, frequently seeking amongst themselves a middle position.” Having forgotten the habit of burning one another at the stake, she continued, they would never again contemplate the act. Instead, they would say to those who sought to burn a heretic, “He is a man, just as I am; and according to Her Majesty’s Nakaz, we are obliged to do as much good, and as little harm as we can.”

In all likelihood, Voltaire no more believed Catherine’s story than we do, if only because it resembled his own story, told 30 years earlier in his Philosophical Letters, of the tolerance shown one another by Jews, Christians, and Muslims in the London Stock Exchange. Still, both tableaux ignore reality in order to project a better reality. Hence the dazzling pomp and circumstance with which Catherine opened the convention. Draped in a majestic imperial robe and flanked by court officials, the empress looked on while her vice chancellor, Alexander Golitsyn, delivered the official welcome. He reminded the representatives why they had been called to Moscow — to work toward “the common good, the felicity of mankind, and the introduction of good manners and humanity, tranquility, security, and felicity to your dear fatherland.” All five hundred or so deputies then filed past Catherine, kissing her hand.

It was all downhill from there. The deputies were read the riot act: they were forbidden from interrupting or punching one another. (They would have had to use their fists, since swords were also forbidden.) Brawls, though, were the least of Catherine’s concerns. Each representative had, in effect, been deputized to present a list (a miniature nakaz) of proposals and grievances from their locality. Compounding the sheer number of nakazes was, in many cases, their excessive length and execrable literary quality, making the task of reading them downright Sisyphean. Moreover, as absolute beginners in public debate and policymaking, the deputies had to juggle strange rules of decorum with equally strange political concepts.

Though she observed the opening sessions, Catherine had, like the god of Voltaire’s imagination, deliberately removed herself from her creation. Unlike Voltaire’s god, however, Catherine could not ignore her creation’s sputtering. She streamed dozens of memos to her officials, venting over the sluggish pace of their work. In the hope of jolting the commission, Catherine peremptorily moved the proceedings, in the dead of winter, from Moscow, a city she so disliked, to her beloved St. Petersburg. But the change of scenery failed to alter the speed of the commission’s deliberations.

Tellingly, the only subject that galvanized the aristocratic deputies was serfdom. Though Catherine had been in power for five years, she was caught off guard by the vehement opposition to the slightest amelioration of the system of indentured servitude: it was a world over which even the Minerva of the North was powerless. Her chief minister, Nikita Panin, blurted: “These axioms capable of toppling walls.” Twenty years after the commission, Catherine remained stunned: “You hardly dare say that [the serfs] are just the same people as we; and even when I myself say this I risk having stones hurled at me […] I think there were not even 20 persons who would have thought about this subject humanely and as human beings.”

By the end of 1768, as her enthusiasm dimmed and her attention turned to imminent war with the Ottoman Empire, Catherine postponed the sessions. She never reconvened the Commission, even after Russia emerged the battered victor of the long and costly Russo-Turkish War in 1774, and the codification never crystallized. To be sure, the promise of the Nakaz was not forgotten by enlightened opinion in Russia and abroad. Translated immediately into English, German, and French, it was banned by Louis XV — an act that, inevitably, bolstered Catherine’s standing among the philosophes — but was widely available in bookstores in St. Petersburg and Moscow.

In the end, did any of this matter? Clearly, for Russia’s millions of serfs, it did not. As the recurrent spasms of peasant revolts revealed, their lives remained as grim as ever. Nevertheless, Catherine made certain that a number of the Nakaz’s principles, particularly those dealing with crime and punishment, found their way into Russian law and helped prepare the ground for the serfs’ emancipation a century later in 1861. But Catherine’s failure to realize her greatest ambitions also reminds us of the limits placed on even the most enlightened and energetic ruler. Catherine made this point, as only she could, in a conversation with Denis Diderot, the editor of the Encyclopédie and the Enlightenment’s most original and radical thinker. “While you write on unfeeling paper,” she told the philosophe, “I write on human skin, which is sensitive to the slightest touch.” Two hundred and fifty years later, in a world where autocratic thugs reign at the two extremes of the Western world, the realism and humanism espoused by a Russian empress are as unexpected as they are urgent.

Robert Zaretsky teaches in the Honors College at the University of Houston. He is the author of numerous books and articles on French intellectual history. He is also the history editor at LARB.

This essay is drawn from Robert Zaretsky’s  book about the unlikely friendship between the revolutionary thinker Denis Diderot and Catherine the Great.

“I Write on Human Skin”: Catherine the Great and the Rule of Law. By Robert Zaretsky. Los Angeles Review of Books ,  July 30, 2017. 

A much-awaited carriage carrying the philosopher Denis Diderot arrived in Saint Petersburg. His initial welcome, unhappily, failed to make him feel any more alive. Before leaving Paris, he had arranged to stay at the house of his friend, the sculptor Etienne-Maurice Falconet. Along with his assistant (and companion) Marie-Anne Collot, Falconet had gone to Saint Petersburg in 1766 in order to undertake, thanks to Diderot’s enthusiastic recommendation, Catherine the Great’s commission for a monumental equestrian statue of Peter the Great. When he wasn’t cheering on Falconet as he labored over his commission—“Work, my friend, work with all your force! Above all, give us a beautiful horse!”—Diderot was busy imagining their happy reunion in Russia. In fact, he scripted and staged the moment they would again see one another: “What a day! What a moment that will be, for both of us, when I knock at your door, enter the house, throw myself into your arms and we begin to cry out confusedly. ‘It’s you.’ ‘Yes, it’s me.’ ‘Well, you finally made it.’ ‘Yes, I did.’ Yes, we’ll babble! And pity the person who, seeing again a friend after a long absence, can speak clearly and not babble.”

When Diderot arrived at Falconet’s residence on the Millionaya, the aptly named street across from the Winter Palace, the only element from his imagined tableau was the babble. But it was babble bred of embarrassment. The weary traveler had barely stepped into the house when Falconet informed him that his son had unexpectedly arrived in Saint Petersburg. Indeed, Pierre-Etienne Falconet, who had been studying with Sir Joshua Reynolds in London, had in fact showed up without warning at his father’s door. What he didn’t tell the uncomprehending Diderot was that Pierre-Étienne had arrived nearly two months earlier. In a letter to Catherine, in which he announced that it was “raining Falconets,” the less than pleased father allowed his son to take the bed he had prepared for his friend Diderot. Oddly, though, he neither sought to find different lodgings for Diderot, nor seemed especially regretful over the turn of events. Stricken by his friend’s news and seeming coldness, “the philosopher’s heart,” later wrote his daughter Angélique, “was forever wounded.”

Diderot did not have the time to tend to his wound. What was he to do, where was he to go? How could he, in his weakened condition, think of putting up at a hostel? Was this, then, to be the climax of his epic trek across the continent? “There I was,” he reminded Nanette, “sick and a stranger in a city where I didn’t understand a word.” At that moment, he suddenly thought of Narishkin. Penning a desperate note to his traveling companion, Diderot had his reply within the hour: a carriage pulled up in front of Falconet’s door to carry the homeless philosopher back to the Narishkin palace, a snowball’s throw from the Winter Palace and sharing the same wide square dominated by the Cathedral of Saint Isaac.

At his host’s firm insistence, Diderot would remain there for the entirety of his stay. Tellingly, though, he almost immediately began to dream about his return to France. It would be a roundabout return, he mischievously tells Nanette. Continuing east to the Great Wall of China, he announces, he would push across Asia and the Ottoman Empire, pass through Constantinople and sail to Carthage. Once back in France, he would stop at several cities, lay over in Langres and, only then, come home. “But you will tell that it’s hardly worth so much effort to find one’s resting place; and you would be right. You will also tell me that I must return as quickly as possible by the shortest route; and you would be right. And so, that is what I will do, and we will have, after the torments of our long separation, the quiet joy of being together again.”

Just as the great distance now separating him from Nanette cast a golden haze over the realities of domestic life, the close proximity to Catherine began to clear away the comforting illusions Diderot had held about the Russian empress. He certainly had time to dwell on the matter, since a week passed between arriving in Saint Petersburg and meeting his host. Yet another bout of colic, which he blamed on the waters of the Neva, forced Diderot to spend several days in his bedchamber. The delay suited Catherine, who was attending to a crucial matter of state: Paul’s wedding to Princess Wilhelmina of Hesse-Darmstadt, a marriage Catherine arranged following her son’s recovery from his bout of influenza. Orchestrating the many festivities then unfolding in the city, Catherine had little time to think about her newly arrived guest.

As for the guest, barely strong enough to lift himself from bed, he had nothing but time to think about his still-unseen host. More precisely, Diderot had time to think about his proper relationship to Catherine. This was an unusual, if not unprecedented, situation for a philosopher. It was even more unusual in Diderot’s case. He was, after all, someone who, when not being kept in prison by his own government, was kept at arm’s length by salonnières because he was as careless in editing his conversation as he was his writings. But Diderot knew that Catherine already knew all of this, just as she knew—or so he assumed—that he had not made this cross-continent trip simply to express his gratitude for the gifts she had showered on him.

As soon as Catherine had bought his library, Diderot understood that she had also bought, if not him, at least his nonrefundable ticket to Saint Petersburg. That he would have to go one day was clear; less clear was how he should act once there. “How can Denis le philosophe,” he wondered, “deserve to be called a collaborator of Catherine’s? How might he also work for the happiness of the people?” There was little modesty in these repeated self-interrogations, and why should there be? “I’m high-minded and, on occasion, come across great and powerful ideas that I convey in a striking fashion. I know how to captivate, move and touch the minds of others.” Granted, d’Alembert is better at differential equations, Diderot allows, but his erstwhile colleague cannot match his gift in “elevating and inspiring the love of virtue and truth.” But therein lies the rub! How could such a man survive at the imperial court? “I always wear my heart on my sleeve! I am incapable of lying, incapable of hiding my affection and distaste, and incapable of avoiding traps that others might lay for me!”

Instead, he had explained to Nanette, his mission was to show Catherine, a ruler who could do so much good, her proper image. “Don’t scold me for this trip,” he pleads: “I had a duty to do.” But how would he reconcile this particular duty toward an empress with the philosopher’s general duty to seek and tell the truth? In his Pages contre un tyran, Diderot did not hesitate to lecture Frederick: “To whom should a philosopher address himself frankly, if not to a sovereign?” But even though Diderot had been able to give Berlin wide berth, he could not escape the gravitational pull of Saint Petersburg. Having resisted for so many years, he finally resigned himself to address his thoughts to Catherine; now, he had to find the means to gently couch his candor.

One rule was never to pretend that he knew better than the empress. This was the fatal mistake committed by his fellow philosophe, Lemercier de La Rivière, whom Diderot had the misfortune to recommend to Catherine in 1768, declaring that if the empress had the hankering for truth, then La Rivière was her man. So much her man, Diderot emphasized, that La Rivière is “our consolation for the loss of Montesquieu.” Catherine, however, decided she had been sold a false bill of lading. Though La Rivière met the empress just once, that was clearly more than enough for Catherine. The “beautiful soul” and “brilliant mind” that Diderot saw in La Rivière were quite lost on Catherine. While a solid economist—Adam Smith thought highly of La Rivière’s work—the Frenchman was a bumptious diplomat who had clearly come to Russia to lecture, not learn. During his shorter-than-anticipated stay in Saint Petersburg, La Rivière’s imperious character so annoyed the empress that she dismissed him as “Solon-La Rivière.”

Diderot thus sought the role not of Solon, but of Socrates. Not only had others cast him in this role—Grimm liked to call his friend “our century’s Socrates,” while Voltaire dubbed him “Diderot-Socrates”—but Diderot believed himself to be suited to it. He spied the same philosophical lineage in his dedication to virtue and love of dialogue, as well as in the same fates nearly shared by the modern Parisian and the ancient Athenian. In a letter to the royal censor Malesherbes, in which he lamented the relentless attacks on the Encyclopédie, Diderot compared his own imprisonment to Socrates’s death: “For ten years, for thirty, I have drunk bitterness from an overflowing cup.” The Socratic reference is clear; among the occupations Diderot pursued to while away the time in Vincennes was a translation of Plato’s Apology of Socrates.

Who can say whether Diderot saw Catherine as Alcibiades, the Athenian leader who had been one of Socrates’s students and, depending on one’s view, either spectacularly realized or rubbished the master’s teachings. Diderot did see himself, though, in the Socratic role of gadfly, as a bringer of questions as much as truths. But crucially, he knew he was a gadfly that could be swatted away by the flick of an imperial wrist. In his preliminary notes for his sessions with Catherine, Diderot seems determined to remind himself as much as his imperial host that he is not La Rivière. The economist, he agreed, was someone who “rather ridiculously gave himself too much importance.” Do not think, Diderot announces, that I will be the sort who, having just arrived and my bags still unpacked, declares: “Madame, stop what you are doing. Nothing good can be done until you hear me out. I alone know how to administer an empire.”

This led Diderot to embrace a second rule: gratitude always means saying you’re sorry—sorry for unavoidable missteps and misunderstandings, sorry for the inevitable impression of not appearing grateful enough. Far from being another La Rivière, Diderot exclaims, he is himself “nothing, really nothing at all.” Everything he now has—“well-being, peace and security”—he owes to Catherine. Indeed, if he is anything at all, he is like a child whom Catherine will “permit to say all the stuff and nonsense passing through his head.” In another memo, he instead portrays himself as “Denis le philosophe”—a dreamer, one who “takes the liberty of addressing his daydreams to Her Imperial Highness.” Yes, these reveries might well contain information, even insights on occasion. More important, though, is the light Diderot wants to throw on the utterly different worlds the two interlocutors inhabit. Their conversations, he proposes, will reveal “all that separates the thoughts that occupy the mind of a ruler and the ideas of a poor devil holding forth from his garret.” Nothing is easier, Diderot admits, “than to run an empire while one’s head rests on a pillow.”

Rarely has such a commonplace been given such uncommon force as, a week after his arrival, Denis le philosophe was well enough to raise, not just his head, but also the rest of his body in order to meet Catherine at a masked ball in the Winter Palace.

Who was the actor, then, and who was the audience when Diderot and Catherine finally met at the palace masquerade? When Diderot, stooping slightly and hesitant, was led to Catherine, who was surrounded by a knot of courtiers, the contrast could not have been more jarring. Not only had he crowned himself with a borrowed and ill-fitting wig—replacing the one he had lost in Germany—but he had also donned his philosopher’s mantle: a plain black suit. Standing in the midst of more than a hundred brilliantly masked and garbed guests, Diderot’s drab appearance sparked expressions of wonder and shock. “Everyone judges him on this [sartorial] singularity alone,” observed L. H. Nicolay, an adviser to Grand Duke Paul. For Nicolay, the Russian aristocracy’s reaction to Diderot’s appearance underscored “how terribly hard it is to maintain a great reputation, and how dangerous it is to leave one’s study for a brilliant court.”

Yet Diderot was more aware of this “singularity” than Nicolay. Despite his nearly comic appearance and gestures, the philosophe was anything but naive. Shortly before he had left Paris, he sent a note to Madame Geoffrin, thanking her for the gift of a new dressing gown. Touched by her gesture, Diderot was also saddened. “Cursed be the miscreant,” he exclaims in mock outrage, “who invented the art of rarifying a piece of ordinary cloth by simply dyeing it scarlet!” The new gown, he moans, is not only stiff and rigid, but conveys a public image at odds with its wearer’s self image. While he now looks like a “mannequin,” the old one’s streaks of ink and layers of dust “showed me to be an author and honest laborer. But now I look lazy and rich, and nobody can tell who I am.”

No doubt as Diderot wished, everyone that night at the Winter Palace could tell who he was—or, rather, who he wished to be seen as. His “philosopher’s coat” stood out as starkly among the masked Russian aristocrats as did Saint Petersburg’s palaces among the military barracks and workers’ hovels. It was the sartorial equivalent of Diderot’s short story “This Is Not a Story,” which both adopted and undermined the foundations of fictional realism. In short, it was a costume that was not a costume.

Catherine, perhaps, was alive to this particular masquerade and determined to play an equal role. Superbly indifferent to her guest’s appearance, she asked him to sit down and recount his trip. Though they conversed for nearly an hour, Diderot later swore he was so “agitated and flustered” that he could not remember a single word he said. Whatever Diderot did say, though, “pleased her greatly”—so much so, he reported, that he could tell from Catherine’s responses that she was “deeply affected.” While we cannot plumb the depths of Catherine’s feelings, she was no doubt moved. Standing in front of her, after all, was the man upon whom she had showered so much attention and money, and to whom she had issued so many indirect, yet increasingly insistent invitations. Have him come to Saint Petersburg, she instructed his friends, if only to show his gratitude. Voltaire was too old, d’Alembert too rude, and Diderot was the last great philosophe standing. And now, here he was: What greater claim to the applause of the Republic of Letters? Or, for that matter, what greater promise was there for conversation as entertaining as it was enlightened? As Catherine gazed on her visitor, his wig registering his frantic arm gestures while his words cascaded above the heads of a mesmerized audience, she admired the role she played in the spectacle as much as she did the role played by Diderot.

As she brought their conversation to an end, Catherine pointed to the door that led to her private apartments: “Monsieur Diderot, do you see that door? It will be open to you every day from three to five.”

Adapted from Catherine & Diderot: The Empress, the Philosopher, and the Fate of the Enlightenment by Robert Zaretsky, published by Harvard University Press.

The Unlikely Friendship between an Philosopher and an Empress. By Robert Zartetsky. LitHub  ,  February 22, 2019

The Enlightenment is under very bad weather right now. The French eighteenth-century movement that once was seen to have bathed Europe in the light of reason—fighting for science against superstition, and for liberty against bondage—has become the villain of many a postmodern seminar and of even more revisionist histories, from left and right alike. The Enlightenment’s supposed faith in reason—its desire to be sure that every “passion’ll / soon be rational,” to adapt the enlightened Ira Gershwin—is held responsible for racism, colonialism, and most of the other really bad isms. Enlightenment order is now understood as overlord violence pursued through other means. Its true symbol is not some peaceful Temple of Reason but the Panopticon—the all-surveying, single-eye system of Jeremy Bentham’s ideal prison. Where pre-Enlightenment Europe was sporadically cruel, post-Enlightenment Europe was systematically inhumane; where the pre-Enlightenment was haphazardly prejudiced, the Enlightenment was systematically racist, creating a “scientific” hierarchy of humanity that justified imperialism. “Reason” became another name for bourgeois oppression, the triumph of science merely an excuse for more orderly forms of social subjugation.

Well, all views produce counter-views, but—and this is one of the lessons of the Enlightenment itself—they tend to come less often from within the era’s Academy of Orthodoxy than from traditions blooming outside it. So, these days, the anti-Enlightenment view is countered most potently by a set of parallel popular enthusiasms. Outside academia, the Enlightenment is not just in good odor but practically Hermès-perfumed. Voltaire has been the subject of (by my count) five popular and mostly positive biographies in the past decade alone, and now the brightest Enlightener of them all, Denis Diderot, is being newly enshrined in two fine books written by American scholars for a general audience: Andrew S. Curran’s “Diderot and the Art of Thinking Freely” (Other Press) and Robert Zaretsky’s “Catherine & Diderot” (Harvard), an account of Diderot’s legendary collusion with a Russian autocrat.

Diderot is known to the casual reader chiefly as an editor of the Encyclopédie—it had no other name, for there was no other encyclopédie. Since the Encyclopédie was a massive compendium of knowledge of all kinds, organizing the entirety of human thought, Diderot persists vaguely in memory as a type of Enlightenment superman, the big bore with a big book. Yet in these two new works of biography he turns out to be not a severe rationalist, overseeing a totalitarianism of thought, but an inspired and lovable amateur, with an opinion on every subject and an appetite for every occasion.

He was and remains, as Zaretsky says simply, a mensch. He is also a very French mensch. He is a touchingly perfect representative—far more than the prickly Voltaire—of a certain French intellectual kind not entirely vanished: ambitious, ironic, obsessed with sex to a hair-raising degree (he wrote a whole novella devoted to the secret testimony of women’s genitalia), while gentle and loving in his many and varied amorous connections; possessed of a taste for sonorous moralizing abstraction on the page and an easy temporizing feel for worldly realism in life; and ferociously aggressive in literary assault while insanely thin-skinned in reaction, littering long stretches of skillful social equivocation with short bursts of astonishing courage.

It has been said that there were two Enlightenments, one high and one low. The high Enlightenment was the Enlightenment that produced the weighty works and domineering ideas; the low, or popular, Enlightenment was—in ways that scholars as unlike as Jürgen Habermas and Robert Darnton have been illuminating for the past half century—the Enlightenment of the cafés and conversation, or, at times, of pamphleteering and pornography.

Until the moment, in the late seventeen-forties, when he was asked to undertake the Encyclopédie, Denis Diderot was mainly a figure of the low Enlightenment, and might have seemed a quite improbable encyclopedist. The ne’er-do-well son of a wealthy provincial bourgeois family, he ducked out of an apprenticeship in law and became a figure of the cafés, known for his conversation and social amiability. His friendship with Jean-Jacques Rousseau, which lasted for nearly twenty years—longer than almost anyone else sustained a friendship with the ornery and paranoid Swiss philosophe—began when they met drinking coffee and playing chess in the Café de la Régence, one of the cafés clustered around the Palais Royal, in Paris, where the real reservoir of Enlightenment social capital was produced. Diderot has such an engaging aura in his writing that an idealized Fragonard portrait of a reader at work—open collar, wigless, bright-eyed and wry—was, until 2012, falsely identified as Diderot. (He isn’t nearly so handsome in any of the surviving frontispieces to his work.) It was the way Diderot ought to have looked, even if he didn’t.

From an early age, he loved women and women loved him back. (His marriage to, of all people, an oddly wellborn working laundress named Toinette was not a success; she would have street brawls with his mistresses.) He had what we call charm, the ability to present intelligence as though it were identical with amiability: he knew that we are sooner seduced by someone who is smart enough to enlist our sympathy than by someone who tries to enlist our sympathy by being smart. Almost alone among his peers, he was presciently aware that chattering could be a way of mattering. “What we write influences only a certain class of citizen,” he once wrote about his circle of confrères, “while our conversation influences everyone.” He understood that civil society, radiating out from the small circles of the cafés to a larger civilization, could change public opinion, noting “the effect of a small number of men who speak after having thought,” and whose “reasoned truths and errors spread from person to person until they reach the confines of the city, where they become established as articles of faith.” Minds made talk; talk made minds.

One couldn’t just drink coffee and talk and still make a living, though—especially after Diderot was disinherited for his bohemianism by his bourgeois dad. He became a miscellaneous essayist and translator, scuffling to make a living by writing political pamphlets, philosophical dialogues, and pornographic books—all the while carrying on vigorous romantic liaisons with a variety of partners, from the local washerwoman to aristocratic readers. His fortunes were boosted by his first popular hit, the 1748 novel “Les Bijoux Indiscrets,” or “The Indiscreet Jewels,” which was a sort of “Dangerous Liaisons” of lingerie. Though “Les Bijoux” acquired a reputation as a “ribald classic,” it has a more than respectable literary pedigree; a regular theme of the French Enlightenment was that the way we love and the way we learn, the forms of sensual desire and the forms of scientific description, might be intimately connected.

Still, “Les Bijoux Indiscrets” must be among the strangest books of philosophical pornography ever published, even in that highly competitive French Enlightenment division. Its story tells of a sultan, evidently a correlate for Louis XV, who acquires a magic ring that empowers, or compels (the sexual politics here are tricky), vaginas—those bijoux, or jewels—to tell their true histories from within women’s underwear. (A contemporary English translation calls them, perhaps more in Diderot’s spirit, “toys.”) One after another narrates a tale, typically of unrepentant infidelity to its official male “owner.” These revelations, treated more as genial truths than as adulterous shocks, give way from time to time to broader speculations. (“The soul remains in the feet to the age of two or three years; at four it inhabits the legs; it gets up to the knees and thighs at fifteen.”) The climax of the book, a marriage of pornography and the philosophy of science which, in modern terms, could have been written only by Karl Popper in collaboration with Terry Southern, occurs when the sultan has a dream in which he sees Plato and his followers, who are blowing bubbles in a temple of Hypothesis (i.e., mired in idle philosophical speculation). Suddenly, an expanding phallic figure appears:

       In the progress of his successive growth, he appeared to me under a hundred different forms; I saw him pointing a long telescope toward the sky, estimating the fall of the bodies with the help of a pendulum, noting the gravity of the air with a tube filled with mercury, and breaking down light with a prism in hand. It was then a huge colossus; his head touched the heavens, his feet were lost in the abyss, and his arms extended from one pole to the other. . . .

  “What,” I asked Plato, “is this gigantic figure approaching us?”

“It is Experience itself,” he answered.

Scarcely had he offered this brief reply when I saw Experience approaching, and the columns of the portico of hypotheses began tottering, its vaults sagging and its floor opening under our feet.

   “Let’s flee,” said Plato. “The building is about to collapse!”

The triumph of Experience (a word that can also mean “experiment” in French), armed with telescopes and pendulums, over Hypothesis is imagined in unmistakably erotic terms—Enlightenment as erection, the new sciences its Cialis. Curran tells us that “Les Bijoux” is catnip to gender studies in academia, though subject to contesting views. One view is that it represents phallocentric condescension to female sexuality—with the women’s bijoux “compelled” to confess—while the alternate, and on the whole more persuasive, view is that it is, for the period, essentially a feminist tract: women’s sexuality is allowed to speak freely, unashamed of erotic appetite even when it represents infidelity to the “owner.”

Diderot would have wanted it to be read in this way. He was in favor of pleasure, and, though famous as a libertine, he urged his lovers to seek orgasmic satisfaction, to recognize that their pleasure was as much a pleasure to him as his own. In a letter, he urged one of his mistresses, Sophie Volland, to own her pleasure, as we might say now: “Since the face of a man who is transported by love and pleasure is so beautiful to see, and since you can control when you want to have this tender and gratifying picture in front of you, why do you deny yourself this same pleasure?” He was also in favor of treating homosexuality as a normal product of human physiology. “Nothing that exists can be against nature or outside nature,” he wrote of same-sex love. Diderot’s idea of enlightenment included the light of shared and open delight.

For all the general delight of their existence, though, every time the Enlightenment philosophes put pen to paper they put their lives and liberty on the line. As Curran persistently reminds us, thinking skeptically about the truth of religion meant risking prison and persecution. In 1749, as punishment for his skeptical and atheistic pamphlets, most particularly for his “Letter on the Blind” of that same year, an odd mixture of early perceptual psychology and a polemic against Christian superstition (the blind are both those who cannot see and those who choose not to see), Diderot was arrested and imprisoned, without trial or process, in the Vincennes dungeon.

Enlightenment France was not Soviet Russia; sources of power were dispersed through the caprices of patronage and the existence of an aristocracy wealthy enough to be, within limits, independent of the King. (The affection of Madame de Pompadour, Louis XV’s mistress, later proved vital for the continuation of the Encyclopédie.) Rousseau visited Diderot in the dungeon, and Voltaire, who had admired Diderot’s pamphlet, had his brilliant physicist-mistress the Marquise du Châtelet write on Diderot’s behalf for kinder treatment.

Yet the threat of imprisonment or exile never entirely let up. The Church, through its civic instruments, regularly jailed, threatened, and harassed proponents of the new learning. What Diderot faced was not the bored disapproval or the condescending tolerance that Christians now complain of coming from liberal élites; it was actual persecution, a desire to imprison those guilty of heretical thought, to close their mouths and eradicate all trace of their books.

Pornographer, polemicist, prisoner of conscience: it was not exactly the C.V. one would expect of an encyclopedia editor. Yet when, in 1747, Diderot was approached to oversee the project (first to update an older English encyclopedia, and then to make an entirely new French one) he jumped at it, and persisted with it—in the face of that sporadic persecution, dilatory contributors, and the sheer weight of the impossible ambition—until it was finished: a couple of dozen volumes, with seventy-two thousand articles and three thousand illustrations, a compendium of all knowledge everywhere.

The Encyclopédie is at once omnipresent and occult. It was a call to new learning, available to all, but now the only people who can read it are experts on the Encyclopédie. Curran makes it clear that long stretches, particularly of the beautifully rendered plates, which celebrate obsolete technologies and crafts, now have a Surrealist edge of particularized meaninglessness. At the same time, he helps us see that the project, far from being the expression of a Panopticon-like supervisory intelligence ordering an unruly world, is improvisatory, wildly eclectic, and “hyper-linked” in its very nature—a set of “brilliant feints, satire, and irony,” as Curran characterizes it.

To protect against charges of impiety, for instance, pieces were commissioned on Biblical history from pious Catholics—one was a long, sober entry on the architecture of Noah’s Ark and the logistics of animal warehousing—in the confidence that readers would find them obviously absurd. More subtly, as Curran argues, Diderot’s insistence on organizing the Encyclopédie alphabetically “implicitly rejected the long-standing separation of monarchic, aristocratic, and religious values from those associated with bourgeois culture and the country’s trades.” Theology and manufacture, chalices and coaches, had to coexist in its pages, and on equal footing. You never knew where in the world you might swoop, high or low, when you turned the page.

And the Encyclopédie was weirdly capable of being read in multiple ways in multiple settings. Working with the mathematician and fellow-polymath Jean le Rond d’Alembert, Diderot seeded the text with a pattern of often obscure renvois, cross-references, designed to show that one subject of study could lead to another in a surprising way. “At any time,” Diderot explained, “Grammar can refer [us] to Dialectics; Dialectics to Metaphysics; Metaphysics to Theology; Theology to Jurisprudence; Jurisprudence to History; History to Geography and Chronology; Chronology to Astronomy. . . .” The system was subtly directional: it showed how a subject could ascend from speculation to experience, from Metaphysics to Astronomy. And yet the Encyclopédie—seventeen volumes of which had appeared by 1765, with many volumes of illustrations to follow—was never meant to be complete. It deliberately linked clashing articles, Curran observes, in order to bring out the crevices and contradictions within the knowledge of the time. It was an invitation to new learning, a truly open book.

Curran does a terrific job of sorting through the crazily complicated history of the Encyclopédie’s publication. At one point, we learn, it was condemned by the Pope as blasphemous; anyone who owned a volume was instructed to hand it over to the local priest for burning. Diderot and his team stepped around the prohibitions by an intricate dance of legalisms, which enabled them, for instance, to continue printing it in France while officially publishing it in Switzerland.

Curran also makes a strong and convincing case that the largely forgotten Louis de Jaucourt, a chevalier, or knight, and a practicing physician, was chiefly responsible for finishing the big book; he produced seventeen thousand articles for it, gratis. He was also one of the most fervent abolitionists in eighteenth-century France, and he brought that fervor to the final volumes of the Encyclopédie. Open-ended, pluralist, anti-hierarchical—the supposedly totalitarian document of absolutist Enlightenment thought turns out, in every sense, to be a manifesto for freedom.

It was Diderot’s reputation as the Encyclopédie man, though, that produced the strangest and most colorful episode in his life, when he accepted an invitation to go to Russia, in 1773, to act as tutor, mentor, and enlightened lawgiver to Catherine the Great. This five-month-long episode is the sole ostensible subject of Zaretsky’s book—ostensible because Zaretsky joyously uses the occasion to write a wonderfully opinionated and erudite evaluation of the whole of Diderot’s career, of the Enlightenment, and of Russian culture. It is an irresistible topic, having already been the subject of several other investigations, as well as of a delightfully Stoppardian novel by the British writer Malcolm Bradbury.

It was a bizarre intersection. An Enlightenment foe of despotism becomes the boy toy of a despot. In truth, the dream of a benevolent monarch who would remake the world in a more rational manner by dictating sound laws to his compliant countrymen is as ancient as Greece and the legend of Alexander being instructed by Aristotle. Voltaire had already, well back in 1740, undertaken something similar with Frederick of Prussia, with predictable futility.

Voltaire’s temptation by Frederick is easy to understand: praise would get you anywhere with Voltaire. Diderot was a more self-aware man; with him, praise would merely get you almost anywhere. His sympathies were, it’s true, limited to people like him; Voltaire’s were limited to people who liked him. Voltaire’s engagement with Frederick was a descent of shared infatuation into mutual disgust. Diderot’s engagement with Catherine—this is the aspect that Bradbury captures well—was marked by half steps, hesitations, ironic asides, pervasive self-knowledge. He was onto her game, and she, surprisingly, was onto his.

As Zaretsky brilliantly illuminates in a discussion of the era’s “philosophic geography,” Diderot grasped that what Catherine wanted, following in the footsteps of Peter the Great, was to “Europeanize” Russia, while what Europeans, including Diderot, wanted was to exoticize Russia. He wanted Russia strange—a new Sparta or a still thriving Byzantium—in order to make it beautiful. What’s more, if Russia was sufficiently alien, moral inquiry could be bracketed for the length of his stay. A serf here and there didn’t obscure the essentially positive picture.

Catherine comes off extremely well in Zaretsky’s account. A German girl whisked off as a teen-ager into a backward Russian court—in one of those forced marriages routinely made among the royalty of the era—she was understandably desperate for a little life of the mind. She had landed smack in the middle of a bizarre ménage, a sort of “Game of Thrones” court, with her own husband, the Tsar-to-be, as the Joffrey of Russia, a mentally (and, it seems, sexually) disabled prince whose only pleasure lay in playing with the toy soldiers he kept in bed. She sensibly took a series of lovers and produced royal pseudo-heirs with them, which her formidably pragmatic mother-in-law, Peter the Great’s daughter, raised as her own.

It was all brutal dynastic warfare and recessive genes and feuding families (her husband reigned for just six months, in 1762, before dying in murky circumstances), with a single crucial exception: Catherine had genuinely altruistic motives to go along with her dynastic ambitions. Having read Montesquieu—indeed, having openly copied from him in her own draft of a Russian constitution, the so-called Nakaz—she had come to believe in the idea of better government and fairer laws and even in the idea of rule by the consent of the ruled. Diderot was her man to bring the hour to hand. When he admired the range of her learning, she replied, “I owe this to the two excellent teachers I had for twenty years: unhappiness and seclusion.”

Diderot thought that the only way to treat a queen was as a woman—a notion that, at times, he seems to have carried right to the edge of danger. Catherine seems first to have been amused, then annoyed, by his familiarities: “I cannot get out of my conversations with him without having my thighs bruised black and blue. I have been obliged to put a table between him and me to keep myself and my limbs out of the range of his gesticulations.” The grabbing seems to have been merely an expression of enthusiasm: he was one of those animated conversationalists—Leonard Bernstein comes to mind—who couldn’t believe that you really got him unless he really got you.

At the start, they nonetheless enchanted each other. “His head is most extraordinary,” she said. “And all men should have the same heart he does.” But he soon grew disappointed. For the catch, of course, with all enlightened despots is that they feel about liberty for their subjects the way the young St. Augustine felt about chastity for himself: they want it, just not quite yet. The philosophe handed her a feverish memorandum for reform, covering everything from rhubarb cultivation to vocational schooling. She listened, rhapsodized, and ignored him.

Zaretsky documents the reasons that, for all Diderot’s good ideas and Catherine’s good will, liberal reform, then as now, did not find root in Russia. A principal one is that Catherine decided she had to put off reform until she had consolidated her power against the intrigues of the Russian court. That meant—despite various feints at creating “intermediary powers” in Russia that could stand between the despot and the people—putting it off for good. The relationship ended badly. Diderot went back west, and wrote a book that witheringly denounced Catherine’s hypocrisy: of her plans for a new constitution, he declared, “I see in it the name of the despot abdicated, but the thing itself preserved.” She responded with predictable indignation and name-calling. She insisted to a later visitor that she had listened patiently to all of Diderot’s good ideas, but that in the end she told him, “You work on paper . . . but I, a poor empress, work on human skin.” The metaphor is just, but crueller than intended: rulers really do write on human skin.

His experience in Russia radicalized Diderot. It turned him from a savant into a liberal. He realized that there would never be an “enlightened” despot, and, when the American Revolution happened, he welcomed it in a way he might not have a decade earlier.

And then, sometime after his return to France, Diderot revised, though he did not publish, the single literary work of his that seems likeliest to last: the philosophical dialogue called by tradition “Rameau’s Nephew.” Set in the Café de la Régence, the same café where he had met Rousseau, it pits a stylized version of an actual louche character of the time—the notorious Jean-François Rameau, who really was the composer’s nephew—against an equally stylized version of Diderot himself. The two—called Lui and Moi, Him and Me—argue about life, inheritance, meaning, pleasure. Lui, Rameau, is the louder voice in the dialogue, speaking up unapologetically for the view that there is nothing in life worth pursuing except immediate physical gratification: food, sex, even defecation. All the higher motives and values that Moi invokes are pious fictions. Rameau’s nephew, as Curran writes, “reduces virtue, friendship, country, the education of one’s children, and achieving a meaningful place in society to nothing more than our vanity. . . . We are all corrupted, acting out various pantomimes to get what we want.” Even his own selfishness, Lui maintains, is the result not of choice but of constitutional and inherited tendencies, the “obtuse paternal molecule” (a strikingly prescient term for DNA) that runs in the Rameau line.

Rameau’s nephew is an amazing invention, alive as a human being on the page in a way that most of the participants in the philosophical set pieces of the time are not. He speaks up so lucidly and passionately for his reductive view that, when the dialogue was at last published—first in German, and long after Diderot’s death—his position was taken for the author’s. It certainly is the more memorable of the two voices.

Remarkably, though, the Diderot character never counters his opponent with references to God or grace or natural law or even the abstract Deistic divine. Instead, his ripostes are every bit as anchored in a materialist view of existence as Rameau’s nephew’s. The argument is simply that there is, in effect, a kinder way to see the material. Confronted with the fact that the most admired moralists in French literature were actually hideously selfish and competitive men, Diderot replies by appealing to the long horizontal frame of history, and by offering the classic incrementalist antidote to cynicism—their shabby original motives are less important than their shining long-term effect:

        Let’s view the matter from the only truly interesting perspective, and disregard for a moment our position in time and space, and look beyond to the centuries to come, to the furthest lands and the peoples yet to be born. Let’s consider the good of our species. . . . Let’s accept things as they are. Let’s see what we lose and what we gain in doing so, and let’s leave aside the big picture which, in any case, we don’t have a clear enough view of to be able to apportion praise or blame, and which          may in itself be neither good nor bad, but simply necessary.

A long perspective, an acceptance of “things as they are,” an empirical summary of gains and losses without hysteria about either: this is still the liberal materialist’s answer to the cynical materialist’s despair, what we have in place of faith.

“Rameau’s Nephew” is, in this way, the first debate between two such materialists, both of whom reject superstition and the supernatural but end in radically different places. We live within that dialogue today, with some of us accepting that the material view of a world without inherent meaning can produce only fatalism, others that it can give us the great if ambiguous gift of freedom. When Sam Harris and Daniel Dennett debate free will, they are reprising Diderot’s dialogue—with Harris arguing, like Rameau’s nephew, that free will is a comforting illusion, enforced by those parental molecules, and Dennett replying, in the voice of Moi, that what we call free will is an emergent property of minds and moves, and that we are as free as we have to be to will what we need. Experience, the expanding germ of thought, is enough. If we experience our lives as free, they are acceptably so. Rameau’s nephew insists that we are soulless bags of meat and blood, even as our minds pretend to have motives; Moi insists that what it means to have a soul is to be a bag of meat and blood with a mind inside.

It’s an argument worth having. In some ways, it is the only argument worth having, since the specific cases are not decidable in advance in one way or another. Sometimes we’ll decide that Lui is right and that what looks like a turbulence of soul and spirit—as with certain psychological disorders—is best viewed as a physiological condition; sometimes Moi seems righter, and our response to other things—human altruism—is little dimmed by talk of flesh and inheritances. We never know until we ask.

Diderot was one of the first to ask. His materialism touches the edge of pathos in its unflinching acceptance of transience. Curran reproduces one of the most moving passages in all his work, from a letter to Sophie Volland, his lover of more than two decades, in which he wrote:

Those people who are buried next to each other are perhaps not as crazy as one might think. Their ashes might press and mix together, and unite. What do I know? Maybe they haven’t lost all feeling or all the memories of their first state. Perhaps there is a flicker of heat that they both enjoy in their own way at the bottom of the cold urn that holds them. Oh, my Sophie, I could touch you, feel you, love you, look for you, unite myself with you, and combine myself with you when we are no longer here. . . . Allow me this fantasy.

“A flicker of heat” was enough to live by. When Voltaire and Diderot met at last, in Paris, in 1778, the long-awaited meeting of the two master minds of the Enlightenment, they had a squabble about Shakespeare. Diderot made a joke about a giant statue that used to stand in front of Notre-Dame, saying that Voltaire’s plays couldn’t touch Shakespeare’s balls. Voltaire did not take it well, and the two parted on sour terms. But the episode is a reminder that the health and vitality of the French Enlightenment lay in the fact that it began and ended in a love of art and literature.

The two American academic authors of these revivifying new books are testaments to Diderot’s legacy, both in the avid lucidity of their writing and in the good humor of their attitudes. They don’t blame him for not being what he couldn’t yet be, nor do they subordinate character to circumstance; they see that without extraordinary characters like Diderot and Catherine the Great there never would have been such a circumstance.

Indeed, one can’t help loving Diderot, even while realizing that the one typical gift of French intellect he lacks is wit. He is funny and good-natured, but, though he attempted a few aphorisms, he left not a single memorable one behind. To think freely, as he did, is to think past shapely sentences to those open books. You can’t make an encyclopedia with a miniaturist’s mind. Wit is, typically, a conservative genre: it summarizes what’s known; to condense a truth to an aphorism, you need to be fairly certain that your listener will accept it as a truth. Diderot was the enemy of truths that people knew already, and so he couldn’t compact—only enlarge.

He wasn’t a wit, but he had a sense of humor, which he applied to the world. His break with Rousseau was caused in part by his inability to accept Rousseau’s sober self-approval for having turned his back on the fashionable world. (“I ask your forgiveness for what I say to you about the solitude in which you live,” Diderot wrote amiably enough in a postscript to a letter, but then added, “Adieu, Citizen! Although a Hermit makes for a very peculiar Citizen.” Rousseau couldn’t stand being kidded that way.)

Heroic materialism may be the hope of our existence; but comic material is the salve of our lives. Diderot exists in memory to show that materialism can be miserable or it can be magical. It all depends on the material, and on the light.

How the Man of Reason Got Radicalized. By Adam Gopnik. The New Yorker  , March 4, 2019.