Darwin's Ghosts

by Rebecca Stott

  When Diderot was released from prison in November 1749, he had become a celebrity not only in Paris but all over Europe. All copies of his Letter on the Blind had sold out. As he returned to his endlessly postponed and arduous work on the Encyclopedia, picking up the reins of this complex and ambitious project, his friend Jean-Jacques Rousseau introduced him to new admirers. In the long entry “Animal” written for the first volume of the Encyclopedia, Diderot wove together extracts from the first two chapters of Buffon’s Natural History, adding to and contradicting his account and describing intermediary creations that bridged kingdoms. In the pages of the article he spliced together Maillet, Maupertuis, Buffon, and Trembley: “Nature advances by nuanced and often imperceptible degrees,” the article declared unapologetically. Hidden away in the pages of the Encyclopedia, Diderot had taken Buffon across the line into terrain where the conservative philosopher was no longer prepared to go—into transgression, into heresy.

  While Diderot was writing this entry, Buffon’s Natural History, now a bestseller across Europe, had run into its own theological tangle. The Jansenists declared it a work of heresy, despite the fact that it had been published by the royal press; it clearly contradicted Genesis, it was a scandal. They demanded that it be censored or burned. In the autumn of 1750, the theologians of the Sorbonne, fearful of public disorder, called Buffon in for interrogation. Buffon agreed to sign a letter retracting fourteen “reprehensible statements” and to publish the retraction in all further editions of the book. He never did so, but he now resolved to be especially careful with the claims he made in future editions. “Sur la scène du monde, je m’avance masqué,” he wrote: “I advance on the world’s stage as a masked man.”

  In his entry, Diderot was taking considerable risks again, only shortly after having been released from prison. But now he was hoping that the sheer volume of the material covered by his new book might serve to shield the ideas from the eyes of the censor and the book police. He thought he could hide anything in there.

  Nanette was pregnant again. Tragically, their four-year-old son, François, died in June 1750 from a violent fever, and the new baby boy, born a few months later, did not survive the year. But still Diderot could not stop, driven now by his philosophical quest. He worked night and day, writing his own entries, checking the proofs of others, asking for revisions, refining and honing. In November 1750, Durand printed eight thousand copies of the prospectus of the Encyclopedia, and in 1751 the first volume appeared. In April 1751, the work had 1,002 subscribers. By the end of the year the number had risen to 2,619. The figure eventually rose to around four thousand.

  Soon after his release from prison, Diderot met a man who would become the most important friend in his life—a patron, fellow philosopher, polymath, translator, and interlocutor, Paul Thiry, Baron d’Holbach. There is no record of their first meeting, but it may have been in the publishing house of Durand on the rue Saint-Jacques—for Durand published both writers—or at a dinner party arranged by Rousseau or in one of the many salons. D’Holbach had arrived in Paris in 1749 from the University of Leiden. Half German, half French, newly married, clever, very rich, and well connected, he lived in an elegant and spacious six-story house in the rue Royale in the middle of a tangle of streets where he threw lavish Thursday and Sunday evening dinners to which he invited some of the most interesting intellectuals of Paris. He was in his early thirties when they met; Diderot was in his early forties.

  Title page of the first volume of Diderot and d’Alembert’s Encyclopedia, issued in 1751.

  The two men quickly discovered a mutual interest in science, particularly in natural history; the baron had already been signed up by Durand to translate German scientific works. Diderot recruited d’Holbach as one of the contributors for the second volume of the Encyclopedia. Soon Diderot was virtually living at the rue Royale, borrowing books from the baron’s enormous library, rummaging through his sprawling and rare natural history collection, or borrowing his microscopes, telescopes, and other optical instruments.

  When Diderot and d’Holbach met, the baron was on a mission: he wanted to put his own knowledge and fortune to good use. Fascinated by the application of science to industrial processes and frustrated by the lack of good translations of some of the most important new books, he had determined to translate German copies in his own library into French. He began with an important seventeenth-century book on glassmaking that he had managed to sell to Durand and publish in 1752. Next he began translations of two German editions of books on mineralogy and hydrology by the Swedish professor of chemistry J. G. Wallerius. Durand gave him more and more work. Over the next fifteen years, he translated a dozen scientific volumes for Durand and other publishers.

  Diderot was also on a mission to bring knowledge directly to the people. He was electrifying—not just clever, but passionate, dogged, disciplined, charming, well read, and rhetorically acrobatic. He contributed more than four hundred articles to the Encyclopedia between 1751 and 1765, long essays on fossils, glaciers, the sea, mountains, stones, strata, earthquakes, volcanoes, mines, and metallurgy, as well as thirty articles on the constitution of the early Roman Empire. He wrote about Iceland; he wrote travel books. And he kept buying books to add to his vast library.

  The baron’s house, often nicknamed the Hotel of the Philosophers or, as Diderot preferred, the Synagogue, was by the early 1750s not only the nerve center of the Paris intelligentsia but also a center of production for the Encyclopedia. It had in addition become a virtual translation factory characterized by a similar intellectual industry to that of the Abbasid Empire at its peak, except that in the Hotel of the Philosophers the emphasis was on the dissemination of clandestine knowledge to the people as broadly as possible rather than amassing libraries of manuscripts for the use of an intellectual elite. Diderot was its engine room. “Let us hasten,” he wrote, “to make philosophy popular. If we want the philosophers to march on, let us bring the people up to the point where the philosophers are now.”

  Unlike Diderot’s lodgings, where spies—concierges, priests, servants—might be listening everywhere, d’Holbach’s house was closed to the police and their enormous network of agents. The baron chose his servants very carefully and ensured that none was present during the dinners that took place every Thursday and Sunday. No one in Paris in the 1750s seemed to be safe from accusation and counteraccusation, not even Buffon himself. The French Enlightenment depended on there being at least one place of absolute intellectual safety and freedom in the capital. D’Holbach guaranteed this.

  If Diderot was the engine room of the d’Holbach coterie, d’Holbach was its choreographer. The baron was a collector of people and a conversation maker above everything else. Rousseau described him as a fervent recruiter of freethinkers. He had a great deal to offer his guests: not only did he employ one of the best cooks in Paris and maintain an extensive wine cellar, he had a library of three thousand books, often with several volumes each in French, German, English, Italian, Latin, Greek, and Hebrew, beautiful pieces of art, a breathtaking natural history cabinet, and a country house in Grandval, just outside Paris, to which he took his friends for shooting, fishing, and walking. Once those conversations began in the rue Royale, with Diderot guaranteeing spectacular intellectual pyrotechnics night after night, it was difficult for the intelligentsia of Paris to stay away.

  D’Holbach was a radical when he met Diderot, and almost certainly a deist. A member of the salon claimed that Diderot converted d’Holbach to atheism while d’Holbach was trying to convince him of the existence of God:

  [D’Holbach] pursued the incredulity of Diderot even into those workshops where the editor of the encyclopaedia, surrounded by machines and workers, was taking sketches of all the manual arts.… [D’Holbach] asked him if he could doubt that they had been conceived and built by an intelligence. The application was a striking one, but it did not, however, strike either the mind or heart of Diderot. Diderot’s friend, bursting into tears, fell
at his feet … he who fell on his knees a deist, got up an atheist.

  But d’Holbach’s atheism was almost certainly also reinforced by the death of his young and pious wife in 1754: she is said to have died in moral agony in fear for her soul. D’Holbach was devastated. Though he married again a year later—his new bride was his wife’s sister Charlotte—and the marriage was a happy one, blessed with several children, d’Holbach’s inability to rescue his first wife from that deathbed terror of hellfire haunted him for the rest of his life and may well have contributed to the furious evangelism of his atheism.

  Certainly Diderot was himself an unrepentant and unwavering atheist by the time he and the baron met. He enjoyed challenging religious belief where he found it, taking on some of the young priests he knew and running rings around their theological claims. But his new atheism did not bring him easy answers to the metaphysical questions about life, its origins, the nature of man, or the variability of species, which continued to fascinate and plague him. In 1753, the year Nanette gave birth to a daughter, Angélique, who was to be Diderot’s only surviving child, he published a further attempt to answer those questions, a book called Thoughts on the Interpretation of Nature (Pensées sur l’interprétation de la nature). It was part of a new intellectual exchange with La Mettrie’s Man Machine and with Buffon, but he had to be careful. He was still under surveillance. He would not risk being taken back to prison, which would certainly be the breaking of him, so he developed new rhetorical and literary strategies. He had learned a good deal from English satirical writers like Jonathan Swift and Laurence Sterne and from La Mettrie himself, who often used evasive phrasing or rhetorical questions to introduce controversial propositions, such as “Ne pourrait-on pas dire que” (Is it not possible to say that …?). If Diderot wanted to bring La Mettrie’s materialism to a wider audience, he had only to appear to be rebutting such ideas while actually pushing them as far as they would go.

  With prison memories sharp in his mind, Diderot now devised still more acrobatic rhetorical strategies, using questions and making radical propositions before veering away from them or refuting them, leaving their color and texture and brilliance still hanging in midair: “May it not be,” he wrote,

  that, just as an individual organism in the animal or vegetable kingdom comes into being, grows, reaches maturity, perishes and disappears from view, so whole species may pass through similar stages? If the faith had not taught us that the animals came from the hands of the Creator just as they are now, and if it were permissible to have the least uncertainty about their beginning and their end, might not the philosopher, left to his own conjectures, suspect that the animal world has from eternity had its separate elements confusedly scattered through the mass of matter; that it finally came about that these elements united—simply because it was possible for them to unite … that millions of years have elapsed between each of these developments; that there are perhaps still new developments to take place which are as yet unknown to us … and that [man] will finally disappear from nature forever, or rather, will continue to exist, but in a form and with faculties wholly unlike those which characterize him in this moment of time?—But religion spares us many wanderings and much labour. If it had not enlightened us on the origin of the world and the universal system of beings, how many different hypotheses would we not have been tempted to take for nature’s secret?

  May it not be … If the faith had not taught us otherwise? It is tempting to imagine poor Joseph d’Hémery in his office, his pen poised over the report he was duty-bound to prepare for the censor, tearing his hair out at such phrases and passages. It was like trying to catch a fish with one’s bare hands. But unfortunately for Diderot, while the rhetorical strategies may have kept the police agents at bay, most reviewers complained that Thoughts on Nature was opaque, incomprehensible, and at best obscure.

  Diderot felt the perpetual presence of d’Hémery, the police agents, and the Paris censors. He sensed them on street corners. No doubt, after his early run-in with d’Hémery, he could now anticipate the police agent’s questions. “He who resolves to apply himself to the study of philosophy,” Diderot wrote resignedly in Thoughts on the Interpretation of Nature, perhaps the most guarded and carefully worded of his books,

  may expect not only the philosophical obstacles that are in the nature of his subject, but also the multitude of moral obstacles that will present themselves, as they have done to all the philosophers preceding him. When, then, it shall come about that he is frustrated, misunderstood, calumniated, compromised, and torn to pieces, let him learn to say to himself, “Is it in my century only, am I the only one against whom there are men filled with ignorance and rancour, souls eaten by envy, heads troubled by superstition?” I am then, certain to obtain, some day, the only applause by which I set any store, if I have been fortunate enough to merit it.

  Buffon chose a more conservative path. By the time the sixth volume of Natural History came out in 1756, the self-censored silences of his work were audible to Diderot and the members of d’Holbach’s coterie. Friedrich Melchior, the Baron von Grimm, Diderot’s coeditor on the Encyclopedia, reviewed it in the Literary Correspondence (Correspondance Littéraire), complaining that this was a book that showed patent signs of censorship: it had been produced, he declared, “in the middle of the persecution incited against philosophy. It was not achieved without frequently sacrificing the liberty and the boldness that speaking the truth demands.” Buffon was, Grimm suggested, either too timid or too clever to speak the truth.

  In 1759 Diderot was still circling around the polyps. After nearly twenty years, the regenerations of the pond creatures no longer vexed but had begun to inspire him. Though he now agreed with La Mettrie’s conclusions, that all living matter drove itself, he could not agree that man was simply a machine. It seemed too reductive, too impoverished a way of seeing. There was something more to be understood from the polyps, something both grandly immortal and communal about their ability to remake themselves, to transcend both the individual body and death itself.

  Diderot met a new interlocutor, Sophie Volland, a brilliant, philosophically minded woman, in 1755. Sophie’s mother, concerned about scandal, made it difficult for them to see each other, so Diderot wrote to her instead, long, delightful letters describing his books and the conversations he was having at Grandval or in the rue Royale. The polyps were on his mind again in a letter to her in 1759. “Tell me,” he wrote from Grandval on a windy, storm-threatened night in October, recalling part of a conversation he had had the previous night with members of the salon,

  have you ever thought seriously about what living means?… The only difference I know between life and death is that now you live in the mass whereas in twenty years’ time you will live in fragments, dispersed and scattered in molecules. Twenty years is a long time!… Perhaps those who have loved one another in life and have themselves buried side by side are not as mad as we think. Perhaps their ashes come together, mingle and unite. Who knows, perhaps they have not lost all feeling or all memory of their former state? Perhaps they still have the remains of warmth and life, which they can enjoy in their own way in the confines of their cold urn. In judging whether elements have life or not, we are guided by what we know of the life of large masses. Perhaps the two things are quite different. People think there is only one sort of polyp, but why shouldn’t all of nature be like the polyp? When it is split into a hundred thousand fragments the original parent polyp no longer exists, but all its elements continue to live.… Do not take this fancy away from me; it is dear to me, for it would give me the certainty of living eternally in you and with you.

  By 1759, when Diderot was forty-six, life had become more dangerous within the d’Holbach circle. The baron, now a zealous atheist, had turned from translating books of science to publishing anti-Christian or deistic works, many by English writers, and he had now determined to import into France and publish openly atheist books, translating them when necessary. Despite the p
rotection of his fortune and his connections, his reliable networks of people who could smuggle manuscripts across the border into Amsterdam to be published, his use of made-up authors’ names or none at all on the title pages, and his ability to pay the substantial costs of the colporteurs, or peddlers, and publishers, the baron was taking substantial risks. The first of the anti-Christian books, Christianity Unveiled (Le Christianisme dévoilé), was published secretly in Nancy in 1761 and then republished at considerable risk and expense in Paris in 1767.

  Copies of the book were dangerous to anyone who bought or sold them. In October 1768, Diderot wrote to tell Sophie about a distressing incident. When a student-apprentice sold his apothecary-tutor one of his two copies of Christianity Unveiled, the master denounced the student to the police as an act of revenge. “The pedlar, the pedlar’s wife, and the apprentice,” he wrote, “were all arrested and they have just been pilloried, whipped and branded, the apprentice condemned to nine years in the galleys, the pedlar to five and the wife to life imprisonment.”

  The police case rattled Diderot. Writing and publishing these books endangered the whole network of people who had come into contact with them. While he might be able to hide his own dangerous ideas in ink clouds, d’Holbach’s prose was uncompromising, bald, and aggressive. It was like gunfire. Once he had started, there was no stopping him. All through the 1760s, d’Holbach produced book after book, each more incendiary than the last.