Denis Diderot

Denis Diderot
Diderot painted by Louis-Michel van Loo, 1767 (Louvre)
Born	(1713-10-05)October 5, 1713 Langres, France
Died	July 31, 1784(1784-07-31) (aged 70) Paris, France
Occupation	Philosopher, writer, encyclopedia editor, art critic
Literary movement	Age of Enlightenment
Notable works	Encyclopédie; Rameau's Nephew; Jacques the Fatalist; The Nun
Spouse	Anne-Antoinette Champion (married 1743)
Children	Marie-Angélique Diderot (Madame de Vandeul)
Signature

Denis Diderot (5 October 1713 – 31 July 1784) was a French philosopher, writer and art critic. He was one of the main thinkers of the Age of Enlightenment, a movement of the 1700s. Its writers and thinkers encouraged people to use reason and to question ideas that had long been accepted.

Diderot is best known as the chief editor of the Encyclopédie (Encyclopedia), one of the largest book projects of the 18th century. It tried to bring together all useful human knowledge. Diderot directed the work for more than twenty years, at first with the mathematician Jean le Rond d'Alembert. He continued the project even when the French government and the Catholic Church tried to stop it.

Diderot also wrote plays, novels, stories, dialogues, art criticism, thousands of letters, and works about science, politics and morals. Many of his most controversial books could not be printed during his lifetime. They appeared only after his death, sometimes many years later. Because of this, much of his fame came in the 19th and 20th centuries, when these works were published. He is generally considered one of the major French thinkers of his century, together with Voltaire and Jean-Jacques Rousseau.

Life

A child in Langres (1713–1728)

Langres, Diderot's home town, seen from its old walls.

Denis Diderot was born on 5 October 1713 in Langres, a small town on a high hill in eastern France. At that time, the town was especially known for making knives.

Didier Diderot, the philosopher's father, a master cutler in Langres.

His father, Didier Diderot, was a master cutler, an artisan who made knives and other cutting tools. He was especially skilled at making tools for surgeons. Members of the Diderot family had worked as cutlers in Langres since the early 1600s, under the shop sign "The Pearl". The family was Catholic and lived comfortably, but it was not noble. All his life, Denis was proud to be the son of a good craftsman.

His mother, Angélique Vigneron, came from a family of leather workers and priests. She was eight years older than her husband. Several of their children died as babies, and Denis was their oldest child to grow up.

Three younger children also grew up. Denise, born in 1715, never married and stayed in Langres. Angélique, born in 1720, became a nun and died young in 1748. The family believed that life in the convent had damaged her health. Didier-Pierre, born in 1722, became a priest and later a canon, a senior official at the cathedral of Langres. The two brothers argued about religion for many years. In the end, they stopped speaking to each other.

Around 1723, Denis entered the Jesuit school in Langres. There he mainly studied Latin, some Greek, and religion. He was a very good student, but he disliked the strict school rules.

According to his daughter's memoir, Denis once told his father that he wanted to leave school and make knives instead. He worked at the family workbench for a few days, but then returned to his books. He said that he preferred impatience to boredom.

His family had already planned a future for him. An old relative of his mother, the canon Didier Vigneron, held a well-paid position in the main church of Langres. The family hoped that Denis would one day take his place.

On 22 August 1726, Denis received the tonsure. This was a church ceremony in which part of a boy's hair was cut. After the ceremony, he was counted as a low-level member of the church. People began to call him "abbé Diderot".

However, the old canon died in April 1728, before Rome had approved Denis as his successor. Many years later, Diderot joked about the church position and the income that he had lost that day.

A student in Paris (1728–1732)

Around 1728 or 1729, his father took him to Paris to continue his studies. It is not certain which school he attended. He probably studied at the Jesuit school of Louis-le-Grand. He may also have studied at the Collège d'Harcourt, which was led by Jansenists, followers of a very strict Catholic movement.

He studied Latin, Greek, rhetoric, mathematics and philosophy. On 2 September 1732, the University of Paris gave him the degree of Master of Arts. He may then have studied theology at the Sorbonne. The records of the Faculty of Theology are lost, so little is known about these years. In the end, he gave up the idea of a church career.

Ten difficult years (1732–1743)

The old Café de la Régence in Paris, a meeting place for chess players, in a 19th-century picture.

His father wanted him to choose a serious profession, such as law or medicine. For about two years, Denis worked in the office of a Paris lawyer named Clément de Ris. He found the work boring and left the job. He had no other plan.

His father told him to choose a career or come home. He also stopped sending him money. For about ten years, Diderot earned money from small jobs. He gave mathematics lessons, wrote sermons for churchmen, and spent a few months as a private teacher in a rich family. His mother secretly helped him. She sent a servant on foot from Langres to Paris with her small savings. Even so, there were days when he was hungry.

During these years, he read constantly about many subjects and taught himself English with the help of a dictionary. He spent hours in Paris cafés, especially the Café de la Régence, a meeting place for chess players. In 1742, he became friends with a young man from Geneva who was also poor and had many ideas, Jean-Jacques Rousseau. Soon afterwards, he became friends with the philosopher Étienne Bonnot de Condillac. The three often ate together and talked about many subjects.

Marriage and family

In 1741, Diderot met Anne-Antoinette Champion, usually called Toinette or Nanette, who was born in 1710. She lived with her widowed mother, and the two women made and sold linen and lace. She was religious and had little interest in books. Diderot fell in love with her and promised to marry her.

Under French law, a son needed his father's consent to marry before the age of thirty. In December 1742, Diderot traveled to Langres to ask for his father's consent. His father learned that the young woman was poor and refused to accept the marriage. He even had Denis locked up in a monastery for a few days. Denis escaped through a window. Back in Paris, the couple married almost in secret, at midnight on 6 November 1743, in a small church. Diderot was already thirty years old, so the marriage was legal. His family in Langres did not learn about the marriage until about six years later.

Their marriage was often difficult. Diderot and his wife had very different interests, and they often disagreed. They had four children, but only the fourth lived. She was a girl, Marie-Angélique, born on 2 September 1753. Diderot loved his daughter very much and gave her a much better education than most girls received at that time. In 1772, she married a businessman named Caroillon de Vandeul. Much later, she wrote down her memories of her father. Her text is still one of the main sources about his youth.

Diderot was not a faithful husband. In the late 1740s, his mistress was the writer Madeleine de Puisieux. Later, from 1755, he had a long and important relationship with Sophie Volland, who is described below.

First books and first troubles (1743–1749)

Title page of the Pensées philosophiques (1746), which the Parliament of Paris ordered to be burned.

To earn money for his family, Diderot first worked as a translator from English. In 1743, he published a French version of Temple Stanyan's Grecian History. From 1746 to 1748, he and two helpers translated the large Medicinal Dictionary of the English doctor Robert James. This work taught him a great deal about medicine, anatomy and natural science.

In 1745, he published his first philosophical book, the Essai sur le mérite et la vertu (Essay on Merit and Virtue). It was a very free French version of a work by the English philosopher Shaftesbury, with many notes by Diderot himself. From Shaftesbury, Diderot took an idea that remained important to him: a person can be truly good without religion, because the wish to do good is part of human nature. The book argues that true virtue must come from a free and unselfish love of what is good. It must not come from the hope of a reward or the fear of punishment. At the beginning of the book, Diderot placed a letter to his younger brother, who was preparing to become a priest. The American scholar Gordon B. Walters showed that many of Diderot's later ideas already appear in the book and its notes.

In 1746, he published the Pensées philosophiques (Philosophical Thoughts) without putting his name on the book. It was a small book of short statements against superstition and faith without reason. It defended a "natural religion": the idea that people can know God through nature and reason, not through churches or miracles. The Parliament of Paris, a powerful high court, ordered the book to be burned in public. The ban made more people want to read it.

In 1748, he published a comic and erotic novel, Les Bijoux indiscrets (The Indiscreet Jewels). The novel quietly made fun of the court of King Louis XV. In the same year, he published a serious scientific work, the Mémoires sur différents sujets de mathématiques (Memoirs on Different Subjects of Mathematics).

In June 1749, he published the Lettre sur les aveugles (Letter on the Blind). The book asks how a person who is born blind understands the world. In its most famous scene, a blind mathematician named Saunderson is dying. He tells a priest that if he is to believe in God, he must be allowed to touch him. The book suggested that all human ideas come from the senses. Diderot even wrote that human virtues depend on the way people feel. He also suggested that nature could have developed slowly through many changes, without a creator. This came close to atheism, the belief that no gods exist. In France in 1749, printing such an idea was extremely dangerous. The police already had a file on Diderot. In it, an inspector described him as a young man full of wit but very dangerous.

Prison at Vincennes (1749)

The keep of the castle of Vincennes, where Diderot was held in 1749.

On the morning of 24 July 1749, two police officials came to Diderot's home with a "lettre de cachet". This was a sealed order in the king's name that allowed the authorities to put someone in prison without a trial. They took Diderot to the dungeon of the castle of Vincennes, east of Paris. Diderot only told his wife that he would not be home for dinner.

At first, he denied being the author of his books, but a publisher had already admitted printing them. After about three weeks, Diderot became afraid that he would remain in the dungeon. He confessed in a letter and promised to show his future writings to the authorities. His conditions then improved. He was moved into the castle, could walk in the park, and could receive visitors.

His wife came to see him. Rousseau also visited him and walked from Paris several times a week. Diderot was set free on 3 November 1749, after more than three months in prison.

After this experience, he published his less controversial books but kept his boldest works unpublished. There was also a practical reason for his release. Diderot was already the director of an enormous publishing project, the Encyclopédie. A group of Paris publishers urgently needed him to be free so that he could continue his work.

The Encyclopédie

Main article: Encyclopédie

How the project started

Title page of the first volume of the Encyclopédie (1751).

The project began as a business idea. In 1745, the Paris publisher André Le Breton wanted to sell a French translation of the Cyclopaedia by Ephraim Chambers (1728), an English dictionary of arts and sciences in two volumes. He joined with three other publishers to pay for the work, but the first editors he chose did not do the job well.

Jean le Rond d'Alembert, Diderot's co-editor until 1758. Pastel by Maurice Quentin de La Tour.

In 1747, Le Breton gave control of the project to two young men: Diderot and the mathematician Jean le Rond d'Alembert. Diderot was almost unknown to the public, but the publishers knew that he was a hard-working translator. The contract of October 1747 promised him a total of 7,200 livres, paid at 144 livres a month. It was not a large wage, but it was the first regular income of his life.

The two editors changed the plan. Instead of simply translating Chambers's work, they decided to create a completely new book. Many specialists would write about different subjects, and the new work would be much larger than the English model. Its title was Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers (Encyclopedia, or a Reasoned Dictionary of the Sciences, Arts and Crafts).

In 1750, Diderot wrote the Prospectus, an advertisement for the future volumes. Thousands of people paid in advance to receive the work. The first volume appeared in June 1751. It began with d'Alembert's Discours préliminaire (Preliminary Discourse), which presented a map of all human knowledge.

What the Encyclopédie was

The frontispiece of the Encyclopédie. At the center, Reason and Philosophy uncover Truth.

When it was complete, the Encyclopédie had 17 volumes of text and 11 volumes of pictures. It contained about 72,000 articles in alphabetical order, written by about 150 people. The writers included Voltaire, Rousseau, Montesquieu, the economist Turgot, the baron d'Holbach, and many others.

The most active writer was the chevalier Louis de Jaucourt. He wrote about 17,000 articles, about one quarter of the whole work. He paid his own secretaries and asked for no payment for his work.

The "figurative system of human knowledge", a map of all knowledge printed in the first volume of the Encyclopédie.

Diderot directed much of the work. He found writers, gave them subjects, and dealt with the publishers. He also wrote several thousand articles himself, especially about philosophy, political ideas, crafts, and trades.

This interest in crafts and trades was unusual. Many educated men looked down on manual work. Diderot, who was the son of a cutler, visited workshops and questioned workers. He described in words and in large detailed pictures how people made stockings, paper, glass, pins, and hundreds of other things. Technical books about trades had existed before, but the Encyclopédie gave unusual respect to the practical knowledge of craftsmen and workers.

A plate from the Encyclopédie showing how pins were made (1762).

Diderot later wrote that he had personally visited the workshops of Paris. He also sent helpers into the great factories of France and even had machines built and set up in his own home.

The historian Jacques Proust showed that Diderot and his helpers also used older technical books, written reports from specialists, and drawings bought from earlier collections. In 1759, an architect named Patte publicly said that the pictures in the Encyclopédie had been copied from an old collection of plates belonging to the Academy of Sciences.

A committee of the Academy examined the matter and found that no printed plate was simply a direct copy. However, modern comparisons show that Patte had some reason for his accusation in the case of several early articles.

The Encyclopédie also criticized many ideas and practices of its time. In ordinary articles, readers could find quiet attacks on superstition, religious persecution, slavery, torture, and unjust laws.

In his own article "Encyclopédie", Diderot wrote that the aim was to collect knowledge from across the world and pass it on to future generations. He also wanted the work to change the general way people thought.

Diderot had to hide some of this criticism. Most articles about religion came from approved Catholic dictionaries, so the book could appear safe. More dangerous ideas were often placed in other articles.

A short article on an ordinary subject could send the reader, through a cross-reference, to another article that contained the real criticism. Diderot himself gave an example. The article "Cordelier" praised an order of monks in polite official language. However, it then sent the reader to the short article "Capuchon", about the monks' pointed hood. There, the order was made to look foolish.

Diderot also hid a defence of freedom of thought inside an article about Aius Locutius, a forgotten Roman god of speech. These methods sometimes allowed criticism to pass through the censors.

In the 20th century, the scholar Joseph E. Barker studied hundreds of the religious articles. He found that most of the text seemed to support accepted religious ideas, while some passages quietly expressed doubt.

Attacks and bans

The Encyclopédie had powerful enemies. These included parts of the Catholic Church, especially the Jesuits, many judges of the Parliament of Paris, and people at the royal court in Versailles. The authorities banned the work twice.

The first volume already contained an article by Diderot called "Autorité politique" (Political Authority). It said that no person receives from nature the right to rule other people. It also said that the prince belongs to the state rather than the state belonging to the prince.

Publishing such words in 1751 was dangerous. The king had told his judges that he was their master and expected them to obey him. The article therefore caused strong attacks, and Diderot became more careful for a time.

At the end of 1751, the abbé de Prades, a churchman close to the encyclopedists, defended a thesis at the Sorbonne. The university judged that some of its ideas were against the Catholic faith. The scandal also affected the Encyclopédie.

Malesherbes, the royal official in charge of the book trade, protected the Encyclopédie. Portrait by Jean Valade.

In February 1752, the king's council banned the first two volumes. However, the project had important supporters. These included Madame de Pompadour and, above all, Malesherbes, the royal official responsible for the book trade. He believed in freedom of thought.

With his help, work on the Encyclopédie soon continued.

According to the memoir written by Diderot's daughter, Malesherbes once warned Diderot that the police had orders to take his papers the next morning. Malesherbes then kept the papers safe in his own home. Nobody would search the home of the man who was himself responsible for controlling books.

The years 1757 and 1758 brought greater danger. After Damiens tried to kill King Louis XV in January 1757, a new law threatened writers of works that attacked religion with death.

Volume 7 then appeared with d'Alembert's article "Genève" (Geneva). The article angered both Catholics and Protestants. Rousseau answered it with a public letter in 1758 and broke with the encyclopedists.

D'Alembert had become tired of the attacks. In the same year, he stopped working as co-editor, although he continued to write articles about mathematics. From then on, Diderot had the main responsibility for editing the work.

In 1759, the authorities took stronger action. The Parliament of Paris condemned the work. The king's council removed its "privilege", the royal permission needed for printing. The Pope placed the Encyclopédie on the Index of forbidden books. The publishers were even ordered to return money to the subscribers.

Diderot refused to stop. He also refused Voltaire's advice to complete the work in another country. He said that the book had been promised to French subscribers and would be made in France.

The government still allowed the publishers to prepare the volumes of pictures because these seemed harmless. Diderot and a smaller group used this permission to continue their work. In secret, they prepared the remaining ten volumes of text.

The new chief of police, Sartine, was friendly towards the philosophers and unofficially allowed the work to continue.

Le Breton's secret changes

In November 1764, when the secret volumes were almost completely printed, Diderot discovered that Le Breton had changed the text without telling him. The publisher was afraid of more trouble with the government and had secretly removed or weakened some of the strongest passages while the books were being printed.

Le Breton had made these changes after Diderot had already approved the pages. He had also destroyed the original texts.

In an angry letter, Diderot told Le Breton that he had destroyed the work of twenty years. However, Diderot could not make the matter public. A public scandal would have destroyed the trust of the subscribers and harmed the other publishers, who had done nothing wrong. He therefore finished the project in silence.

Le Breton's changes affected several dozen articles. In the 20th century, a set of the original proofs was found. Because of this discovery, part of the lost text could finally be published.

The end of the work

In 1765, the final ten volumes of text were printed with a false address saying that they came from Neuchâtel in Switzerland. At the beginning of 1766, they were quietly delivered to the subscribers.

The government did not react strongly. Le Breton spent eight days in the Bastille prison because he had given out copies too openly at Versailles. Diderot even went to the police to speak in his defence.

The eleven volumes of pictures appeared between 1762 and 1772. The whole work was now complete: 28 volumes produced over twenty-five years.

The publishers earned about two and a half million livres. Diderot was paid for each volume, but for the rest of his life he believed that he had received far too little money for twenty-five years of work.

He had created, as he said, a machine for changing minds.

Why the Encyclopédie was important

The Encyclopédie sold well. It was copied and imitated across Europe, and it helped spread the ideas of the Enlightenment far beyond Paris.

It encouraged people to ask for proof, respect science and useful work, and question intolerance and political power that had few limits.

Historians still disagree about how much the Encyclopédie helped prepare the French Revolution of 1789, which began five years after Diderot's death.

For Diderot himself, the need to describe almost every area of knowledge forced him to learn about many different subjects. This knowledge later became an important part of his own books and ideas.

Middle years

Friends and dinners

The baron d'Holbach, painted by Alexander Roslin. Diderot was a regular guest at his dinners.

During these years, Diderot lived with his family in the rue Taranne in Paris. People who knew him described his conversation as fast, lively, and full of images. Some even thought that he spoke better than he wrote.

Twice a week, writers and scientists had dinner at the home of the baron d'Holbach, a rich German-born philosopher and atheist. They met either at his house in Paris or at his country house at Grandval. There they could freely discuss ideas that could not be printed. Diderot was one of the most active speakers at these dinners.

Diderot (seated) with his friend Grimm, in an engraving after a drawing by Carmontelle.

Another important friend was Melchior Grimm, a German writer who lived in Paris. He produced the Correspondance littéraire (Literary Correspondence), a handwritten newsletter about French cultural life. It was sent to a small number of foreign kings and princes, including Catherine the Great of Russia. Because it was not printed or sold in France, it escaped the censors. For twenty years, it gave Diderot a safe way to publish texts that were too controversial to appear openly in France.

Sophie Volland

In 1755, Diderot met Louise-Henriette Volland, whom he called Sophie. She was unmarried, well-read, and clear-minded. Their relationship lasted almost thirty years, until both died in 1784. More than 180 of Diderot's letters to her survive, but her answers are lost. The letters discuss his work, his health, the dinners at Grandval, and his ideas about life and death. They also give a detailed picture of everyday life in Paris during his time.

The quarrel with Rousseau

Jean-Jacques Rousseau, Diderot's friend from 1742 until their quarrel. Pastel by Maurice Quentin de La Tour.

Diderot and Rousseau slowly grew apart. Diderot loved city life, society, and science. Rousseau came to dislike these things and moved to the countryside.

In 1757, Diderot published a line in a play saying that only a wicked man is alone. Rousseau believed that the line was an attack on him. In 1758, he publicly broke with the encyclopedists. Years later, Rousseau accused Diderot of being ungrateful. Diderot answered him bitterly in a book of his own. The two men never became friends again.

Catherine the Great buys Diderot's library

Catherine II of Russia bought Diderot's library in 1765. Painting by Johann Baptist von Lampi.

By the early 1760s, Diderot was famous but not rich. His daughter would soon need a dowry, the money that a bride's family gave when she married. Diderot decided to sell his most valuable possession, his working library of about 3,000 books.

Grimm told Empress Catherine II of Russia about the library. Catherine wanted people in Europe to see her as an enlightened ruler. In March 1765, she bought the library for 15,000 livres. She allowed Diderot to keep the books in Paris and named him librarian of his own library, with a yearly salary of 1,000 livres.

When one year's salary was not paid, Catherine sent him fifty years of salary in advance, a total of 50,000 livres. Diderot no longer had serious money problems, and news of the purchase spread widely across Europe.

Falconet's statue of Peter the Great in Saint Petersburg, known as the "Bronze Horseman". Diderot had recommended the sculptor to Catherine II.

In return, Diderot became a kind of cultural agent for Catherine in Paris. He recommended the sculptor Falconet to her. Falconet later created the famous statue of Peter the Great in Saint Petersburg. Diderot also bought whole collections of paintings for Catherine. In 1772, he helped her buy one of the finest collections in France. Many masterpieces that are now in the Hermitage Museum in Saint Petersburg were bought for Russia on Diderot's advice.

In 1772, his daughter married and received a good dowry. The Encyclopédie was finished, and Diderot now planned to thank the empress in person.

The journey to Russia (1773 to 1774)

Diderot's journey from Paris to Saint Petersburg and back (1773 to 1774).

Diderot was almost sixty and had never really traveled, but, as he said, an ungrateful man discourages the generous. He left Paris on 11 June 1773, stopped for two months in The Hague with his friend Prince Golitsyn, then crossed northern Germany quickly. King Frederick II of Prussia expected a visit; Diderot, who disliked the warlike king, drove around Berlin without stopping, which contemporaries saw as an insult.

He reached Saint Petersburg in October 1773, tired and ill. His old friend Falconet, with whom he had planned to stay, had no room for him; a Russian court noble, Naryshkin, gave him a home instead.

Diderot in Saint Petersburg in 1773, painted by the Russian artist Dmitry Levitzky.

For about five months, the empress received him almost every afternoon for an hour or more of free conversation. He wrote for her dozens of short papers of advice: create schools for all children, develop a middle class, limit the power of the throne, free the peasants step by step. Catherine read them but changed little. According to a memoir writer, she later explained that the philosopher worked on paper, which accepts anything, while she worked on human skin, which is far more sensitive.

Diderot left Saint Petersburg in March 1774 with rich presents and was back in Paris in October, after sixteen months away. It was the only great journey of his life.

At home he wrote for the empress a plan for a complete Russian school system, open to children of all classes, and, secretly, critical notes on the Nakaz, her book of law principles. In these notes he wrote that the highest power, which he called the sovereign, belongs only to the nation, and that a nation should never give complete power to anyone. Catherine read them only after his death and did not like them at all.

Last years (1774–1784)

Old age at work

Diderot in 1784, the year of his death. Painting by Jean-Simon Berthélemy.

After returning to Paris, Diderot slowly took less part in social life, but he continued to write. He revised his unpublished novels and dialogues and filled notebooks with ideas about the human body. He also secretly wrote against European colonialism for a friend's book about European trade and conquest in America and Asia. The book became one of the most successful works of the time.

In 1778, he published a book about the Roman philosopher Seneca. He made it much longer in 1782 and gave it the title Essai sur les règnes de Claude et de Néron (Essay on the Reigns of Claudius and Nero). Seneca had been a philosopher who served a tyrant. By defending Seneca, Diderot was also defending some of his own choices and answering the accusations that Rousseau had made against him.

Voltaire and Rousseau died in 1778, and d'Alembert died in 1783. In February 1784, Sophie Volland also died. A few days before her death, Diderot, who was himself ill, had coughed up blood.

Death

The rue Taranne, where Diderot lived for about thirty years, photographed by Charles Marville around 1866. The street later disappeared when the boulevard Saint-Germain was built.

Diderot's apartment in the rue Taranne was on an upper floor, and his doctors told him not to climb the stairs. Catherine II rented a ground-floor apartment for him in the rue de Richelieu. He moved there in July 1784 and lived there for only about two weeks.

When Diderot saw a fine new bed being set up, he joked with the workers. He said that they were taking a great deal of trouble over a piece of furniture that would not be useful for four days.

On the evening of 30 July, Diderot talked about philosophy with friends who came to visit him. He told them that the first step towards philosophy was unbelief, by which he meant refusing to accept ideas without proof. These were the last words that his daughter heard from him.

The next day, 31 July 1784, Diderot sat down to dinner with his wife. At the end of the meal, he took an apricot, placed his elbow on the table, and died quietly. He was 70 years old.

The next day, doctors opened and examined his body. They found that his heart was greatly enlarged and that one of his lungs contained fluid.

The church of Saint-Roch in Paris, where Diderot was buried in 1784.

People who did not believe in religion could be refused a religious burial. Diderot's son-in-law therefore paid for a very expensive funeral. On the evening of 1 August 1784, Diderot was buried inside the church of Saint-Roch in Paris. Among writers, only his faithful follower Naigeon went with the funeral procession.

During the French Revolution, the tombs inside Saint-Roch were opened and the remains were moved to a common grave. A search in 1879 found nothing. The exact place where Diderot's remains lie is therefore unknown.

In 1785, Diderot's library and a collection of his manuscripts were sent to Catherine II in Saint Petersburg. The books were later mixed with the imperial collections. His manuscripts, however, were kept together. They later helped scholars to publish many of his works that had remained unpublished during his lifetime.

Works

Diderot wrote in almost every literary form. Two features appear throughout his work. He often used dialogue, in which the reader cannot always tell which speaker is right. Also, much of his best writing was not published during his lifetime.

Plays and ideas about theater

Title page of Le Père de famille (1758).

In the 1750s, tragedy and comedy were the two main respected forms of French theater. Diderot argued for a serious form between them. Other writers called it the "drame bourgeois", or middle-class drama. These plays showed ordinary families of the present day facing real problems such as money, work and marriage.

Diderot gave two examples, Le Fils naturel (The Natural Son, 1757) and Le Père de famille (The Father of the Family, 1758). He also added a text about theater to each play. In these texts, he asked actors to behave naturally. He also described an invisible "fourth wall": actors should imagine a wall at the edge of the stage and act as if there were no audience.

Diderot also wanted writers to build their plays around "tableaux", or stage pictures. These scenes should look so natural and true that a painter could copy them onto a canvas. Modern scholars have shown that this idea connects his writings about theater with his art criticism. In both arts, Diderot wanted people to appear completely interested in what they were doing, as if nobody were watching them.

The two plays are rarely performed today, but Diderot's ideas about theater influenced European drama. The German writer Lessing translated both plays and used their ideas in German theater. Diderot helped the development of serious drama about ordinary family and social life. This kind of drama became important in 19th-century European theater and later influenced many stories on stage, in movies and on television.

Diderot returned to the theater in the dialogue Paradoxe sur le comédien (The Paradox of the Actor, written in the 1770s, printed 1830). He argues that a great actor should not truly feel the emotions shown on stage. Instead, the actor should copy their outward signs with complete control. In this way, the actor can repeat the same performance every night. Actors and directors still discuss this idea.

The same text gave the French language a famous expression. Diderot describes a sensitive man who thinks of the perfect answer only after it is too late, when he is already going down the stairs after leaving. In French, this is still called "l'esprit de l'escalier", or staircase wit.

Late in life, Diderot also wrote a comedy, Est-il bon ? Est-il méchant ? (Is He Good? Is He Bad?, around 1781). Its main character, a writer named Hardouin, helps everyone around him, but often does so by lying and controlling other people. The character is in some ways similar to Diderot himself. Many modern critics consider it his best play.

The Nun

Title page of the first edition of La Religieuse (1796).

La Religieuse (The Nun) began in 1760 as a practical joke. Diderot and his friends wanted to bring the marquis de Croismare back to Paris. They invented letters from a nun who had escaped from a convent and was asking him for protection. Diderot wrote the letters. He continued writing after the joke was over, and the letters slowly became a complete novel about the life of the invented nun.

Her name is Suzanne Simonin. She is an honest girl who is forced to enter a convent against her will. She has religious faith, but does not want to live as a nun. She asks only to be free.

The novel follows Suzanne under three very different mothers superior. The first is kind but dies. The second is cruel and treats Suzanne badly. The third feels a confused sexual desire for Suzanne, which frightens her. The novel is not an attack on religious faith itself. It attacks forced religious life and studies what closed institutions can do to people.

Diderot wrote the novel around 1760 and continued to improve it for about twenty years. It was not printed until 1796. In 1966, a French movie based on the book was itself banned for a short time, about two hundred years after Diderot wrote the novel. Another movie version appeared in 2013.

Rameau's Nephew

Le Neveu de Rameau (Rameau's Nephew) is often considered one of Diderot's major works. He wrote and rewrote it in secret for perhaps twenty years, beginning around 1761. No friend seems to have known that the work existed.

The book is one long conversation in a Paris café. The two speakers are called "Me" and "Him". "Me" is a calm philosopher who is much like Diderot. "Him" is based on a real person, Jean-François Rameau, the unsuccessful but brilliant nephew of the composer Jean-Philippe Rameau.

The nephew lives by pleasing rich people so that they will feed and support him. He is also a very gifted talker and mimic who can act out whole operas by himself. He openly defends his way of life. He says that everyone praises people they do not respect and tells lies, and that he is simply better at doing these things. The philosopher defends virtue but often finds it difficult to answer him. The book gives no final answer about which man is right.

One important background to the work was a literary quarrel that began in 1760. In that year, Charles Palissot's comedy Les Philosophes (The Philosophers) made fun of Diderot personally on the stage of the French national theater. Diderot did not publish a direct answer. However, in Rameau's Nephew, he strongly attacked Palissot and other writers who were paid to attack the philosophers.

Diderot gave the book the subtitle "Second Satire", following the example of the Roman poet Horace. Music is also very important in the book. During the 1750s, Paris had seen a strong public argument about opera, between supporters of the older French style and the newer Italian style. Diderot supported the Italians. The nephew also loves Italian music and uses his voice and body to act out this musical argument.

Goethe's German translation of Rameau's Nephew (1805) appeared before any French edition.

After Diderot's death, a manuscript of the work went with his papers to Saint Petersburg. Around 1800, a German visitor secretly made a copy. The copy reached the poet Schiller, who gave it to Goethe. Goethe translated it into German and published it in 1805. Because of this, the first published edition of the French work appeared in German.

The first French editions appeared in the 1820s. At first, the text was translated back into French from Goethe's German version. In 1823, another edition was made from a copy kept by Diderot's family. In 1890, Diderot's original manuscript was found in a secondhand bookstall beside the river Seine. It is now in a library in New York and is the basis of modern editions.

Jacques the Fatalist

The first edition of Jacques le fataliste (1796).

Jacques le fataliste et son maître (Jacques the Fatalist and His Master, written and enlarged from about 1771, printed 1796) is Diderot's other major novel. A servant named Jacques and his unnamed master travel across France on horseback. To pass the time, Jacques tells the story of his loves. He never manages to finish it because their journey is full of interruptions and stories told by other people.

The longest of these stories is about Madame de La Pommeraye and her revenge. It has often interested movie directors. Robert Bresson used it for a movie in 1945, and another French movie retold the story in 2018.

Jacques is a "fatalist". He believes that everything that happens has already been written above on a great scroll, and that there is therefore no reason to complain. His master believes in free will, but does very little. Their argument raises one of the main questions of the book: are human beings free? If they are not, what does it mean to praise or blame them?

The way the story is told is also unusual. The narrator constantly interrupts the story and speaks directly about how he is telling it. He offers several possible endings. At different times, he says that he could invent anything and also that the story is true.

Diderot took some of this playful style from Laurence Sterne, whose Tristram Shandy he admired, but he developed it further. In the 20th century, readers saw Jacques as an early example of a modern novel that openly shows how stories are created. The Czech writer Milan Kundera called Jacques one of the greatest novels ever written and turned it into a play.

Stories and dialogues

Diderot also wrote shorter works of fiction, mostly in the early 1770s. Three connected stories examine the way society judges love: Ceci n'est pas un conte (This Is Not a Story), Madame de La Carlière, and the Supplément au voyage de Bougainville (Supplement to Bougainville's Voyage, written 1772, printed 1796).

In the Supplément, Diderot imagines conversations between Tahitians and Europeans after Bougainville's real journey to Tahiti. A Tahitian elder attacks the European visitors for claiming that the land belongs to them. A Tahitian host named Orou questions the ship's priest about his religion until the priest has difficulty defending his answers.

Through these conversations, Diderot attacks colonial conquest and asks whether European sexual morality comes from nature or only from social custom. He also develops one of his important ideas. Human beings, he says, live under three sets of rules at the same time: the law of nature, the law of the state, and the law of religion. When these three sets of rules disagree, a person may have to break one rule in order to obey another. Diderot therefore argued that a good society should make its written laws agree as closely as possible with nature.

Other short works include Les Deux Amis de Bourbonne (The Two Friends from Bourbonne, 1770), a serious story about friendship among poor people, and the Entretien d'un père avec ses enfants (Conversation of a Father with His Children, 1770). In the second work, members of the Diderot family discuss whether it can ever be right to break the law in order to do good. Again, Diderot gives no final answer.

Art criticism: the Salons

Greuze's painting of a village marriage (L'Accordée de village, 1761), which Diderot praised at the Salon of 1761.

Every two years, the Royal Academy of painting held a public exhibition in the Louvre called the Salon. From 1759 to 1781, Diderot reviewed nine of these exhibitions for Grimm's newsletter. These writings, known as the Salons, made him one of the first important modern art critics.

Behind the reviews was an idea about painting. A painting can show only one moment in a story. Diderot therefore thought that choosing the right moment was one of the painter's most important tasks. The chosen moment should help the viewer imagine what happened before it and what might happen next.

Diderot judged many paintings by this idea. The exhibitions were crowded and did not remain open for long, so he wrote much of his criticism at home from memory. He tried to recreate the paintings for his readers through words.

Diderot drawn by Greuze in 1766.

In his review of 1767, Diderot describes seven landscapes by the painter Vernet as if they were real places. He imagines himself walking through each one and only later reminds the reader that he is describing paintings. He praised the quiet still-life paintings of Chardin. His writing about the ruined buildings painted by Hubert Robert became a reflection on time and the passing of human life.

Diderot especially admired Greuze, a painter of emotional family scenes. When Greuze's painting of a village marriage was shown in 1761, Diderot wrote that there was always a crowd around it. He encouraged Greuze to continue putting moral ideas into his paintings.

Later, Greuze tried to paint grand scenes from history. Diderot told him directly that this was not the kind of painting he did best. Diderot strongly disliked the decorative style of Boucher, the favorite painter of the royal court. He wrote that Boucher had everything except truth and accused him of damaging public taste.

The Salons were printed long after Diderot's death, but they influenced later writing about art. French poets and critics such as Baudelaire continued a way of writing about painting that Diderot had helped to create.

Philosophy and science writings

After the Letter on the Blind (1749), Diderot wrote the Lettre sur les sourds et muets (Letter on the Deaf and Mute, 1751), about language and the arts. In 1753, he published the Pensées sur l'interprétation de la nature (Thoughts on the Interpretation of Nature), a short book about scientific method. In it, Diderot argued that the future of science belonged to experiment and to the study of life, chemistry and nature.

He followed this idea in his own studies. In the middle of the 1750s, he spent three years attending the public chemistry course of Guillaume-François Rouelle and filled notebooks with what he learned.

The Italian scholar Paolo Quintili has described the connection between these different interests. In Diderot's work, science, poetry and philosophy constantly influence and test one another. Materialism, the idea that nature is made of matter and does not need a separate spiritual substance to explain it, connects these subjects. Quintili also argues that Diderot developed many of these ideas through his work on the Encyclopédie.

A harpsichord made in 1612. Diderot imagined a harpsichord that could feel and remember, to explain how matter can think.

One of Diderot's major philosophical works is a group of three dialogues written in 1769 and printed only in 1830, Le Rêve de d'Alembert (D'Alembert's Dream). In the first dialogue, Diderot argues that matter itself can have feeling.

He uses the image of a harpsichord, an early keyboard instrument. He asks the reader to imagine a harpsichord that could feel and remember. Such an instrument could repeat tunes and perhaps even create new ones. Diderot says that human beings are like these instruments: nature acts on the senses, and thought comes from this activity.

In the second dialogue, d'Alembert speaks while dreaming. Julie de Lespinasse writes down his words, and the doctor Bordeu explains them. The universe appears as matter that is always changing. Diderot compares living beings to a group of bees that can act like one animal. He imagines species appearing and disappearing over very long periods of time. He also compares the brain to a spider at the center of a web made by the nerves.

The real Julie de Lespinasse learned about the text and demanded that Diderot destroy it. Diderot promised to do so, but secretly kept copies.

Around the same period, he wrote the Principes philosophiques sur la matière et le mouvement (Philosophical Principles on Matter and Movement, 1770), the Réfutation d'Helvétius (Refutation of Helvétius, mid-1770s), and the Entretien d'un philosophe avec la maréchale de *** (Conversation of a Philosopher with the Marshal's Wife, 1774). In the last of these works, an atheist explains to a religious woman why he still behaves morally.

Diderot also worked on the unfinished Éléments de physiologie (Elements of Physiology). In these notes, he treats thought as something produced by the living body.

Political writings

Diderot wrote his strongest political texts late in life, but some of his political ideas appeared much earlier. In 1755, in the fifth volume of the Encyclopédie, his article "Droit naturel" (Natural Right) and Rousseau's article on political economy both used the idea of the general will.

For Diderot, the general will meant a common rule of justice considered from the point of view of all humanity. A few years later, Rousseau made the general will, understood in his own way, one of the central ideas of his political philosophy.

Title page of the 1780 edition of Raynal's Histoire des deux Indes, for which Diderot secretly wrote many pages.

Diderot also gave political advice to Catherine II. Much of his later political writing, however, appeared without his name inside another man's book. In 1770, the abbé Raynal published a successful history of European trade and conquest in the East and West Indies. He later produced two larger editions.

For the editions of 1774 and especially 1780, Diderot secretly wrote many of the strongest passages. He attacked colonial violence, the slave trade, and slavery itself. He argued that people who are oppressed have a right to rise against their rulers.

Diderot even predicted that enslaved Africans in the colonies would one day find a leader and take their freedom by force. A few years after his death, the revolution of enslaved people in Haiti made this passage famous. When the book was condemned in 1781 and Raynal had to flee, Diderot wrote a defence of him.

Diderot also wrote a memoir about the book trade in which he defended the rights of authors and freedom of the press. He wrote other short works against rulers having complete power. One idea often returns in these late writings: when a people gives up its rights, even to a wise ruler, it teaches itself to live without freedom.

Letters

More than a thousand of Diderot's letters survive. His letters to Sophie Volland are considered among the finest letters written in the 18th century.

Diderot's ideas

Diderot in 1771. Bust by Jean-Antoine Houdon.

Diderot never wrote one complete system of philosophy. He did not trust systems that tried to explain everything, and he often presented different sides of the same question. Even so, some main ideas appear throughout his work. If he had one basic belief, it was the one he described in a letter to Voltaire: the True, the Good and the Beautiful. He called them a kind of trinity that was worth a little more than the religious one.

Religion

Diderot's religious views changed slowly. As a young man, he was a believing Catholic who almost became a priest. The Philosophical Thoughts (1746) defended a "natural religion": belief in a God known through nature and reason, rather than through churches and miracles.

The Letter on the Blind (1749) went further and suggested that nature might not need a creator at all. In his mature years, Diderot was an atheist. He believed that the idea of God was a human invention and that matter in movement was all that existed.

Diderot separated the question of God from the question of morals. Some people argued that without God there could be no moral rules. Diderot answered, both in his books and through the example of his own life, that a person who did not believe in God could still be good.

He strongly attacked organized religion when it forced people to accept beliefs, supported persecution, or joined with political power. He opposed forced religious belief, forced life in convents, and the close alliance between church and monarchy. He also rejected religious teachings that, in his view, could not be supported by reason or experience.

Nature and matter

One idea stands at the center of Diderot's mature philosophy: everything is matter, and matter is active. This position is called materialism.

Many thinkers of his time believed that matter was lifeless and needed God to move it and a soul to give it feeling. Diderot argued instead that matter has activity within itself. Under certain forms of organization, it can become sensitive, then living, and finally able to think. For him, there was no complete separation between a stone, a plant, an animal and a human being. They were different forms and levels of organized matter.

One of his favorite examples was the egg. At first, an egg is only a small mass of matter in which no feeling can be seen. With nothing added except warmth, however, it becomes a chick that moves and has desires.

Diderot also admitted that he could not prove everything in this idea. He called the sensitivity of matter a possible explanation that removed some difficulties. He invited future scientists to prove it or replace it with a better explanation.

A second idea followed from this: nature has a history. Species do not remain unchanged forever. Over very long periods of time, Diderot imagined forms of life appearing, changing and disappearing.

These ideas came long before Darwin's work, but Diderot did not have a theory of evolution by natural selection. He understood nature as a long process of change and saw human beings as products of nature rather than as a separate creation.

Because human beings are part of nature, Diderot gave great importance to the body. He thought that thought, memory and feeling were activities of the brain and nerves.

He also warned against what he called the "sophism of the ephemeral". By this, he meant the mistake of a short-lived being who believes that the world has always been as it appears during that being's own short life. Diderot liked to repeat a joke by Fontenelle. A rose says that, in all the memory of roses, no gardener has ever been seen to die. The philosopher Élisabeth de Fontenay later called Diderot's way of thinking an "enchanted materialism".

Free will and morals

If a human being is a physical system, then human actions must also have causes, like other events in nature. In a private letter of 1756, Diderot accepted this conclusion. In the strict sense, he wrote, there is no free will. A person is no more the complete author of his actions than a river is the author of its course.

However, Diderot rejected only the idea of free will as a power to act without any cause. He did not believe that everything was fixed in advance. Chance, education and circumstances can all change what people become and what they do. For Diderot, the important question was therefore not simply whether people have free will, but whether they can act freely under the conditions in which they live.

Jacques the Fatalist examines this difference between causes, chance and the belief that everything has already been decided. Diderot had changed his mind on this subject. In his first book, published in 1745, he had still argued that there could be no merit or virtue without free choice.

Did this mean that morality had no meaning? Diderot said that it did not. Even if actions have causes, people can still change because education, laws, praise and blame are themselves causes. Society should therefore try to correct people rather than hate them, and try to prevent harmful actions rather than only punish them.

Diderot also believed that some people were born with bodies and minds that made harmful behavior more likely. Society had to protect itself from such people, he argued, just as it protected itself from disease, but it should do so without cruelty.

Diderot connected goodness with human nature. Human beings are social animals, and kindness, friendship and justice answer real human needs. The virtue he valued most was "bienfaisance", or active kindness: doing good to other people.

His friends said that he practiced this kindness so freely that other people sometimes took advantage of him. His enemies believed that a good materialist was impossible. A church writer of the time, the abbé Bergier, said that a virtuous materialist was a mystery that could never be understood.

Diderot often examined moral problems through stories and dialogues. Instead of giving the reader a fixed set of rules, he presented difficult cases and allowed the reader to judge them. For this reason, modern specialists often speak of Diderot's different approaches to morality rather than of one single moral system. In 2022, a collection of studies was published with a title based on this idea.

Diderot did not believe in heaven, but he believed in posterity, meaning the judgment of future generations. He wrote to the sculptor Falconet that, for a philosopher, posterity was what the next world was for a religious person. Working for people who had not yet been born, as he had done with the Encyclopédie, gave him a reason to continue his work.

Politics and society

Diderot never created a complete political system, and his political ideas changed over time. In the Encyclopédie, he already denied that anyone had a natural right to rule other people. At that time, however, he could still accept a strong monarchy under some conditions.

During the 1770s, he became much more critical of absolute rule and defended the sovereignty of the nation more clearly. In his later writings, Diderot argued that political power comes from the people and belongs to them. A king is an agent of the nation, not its owner.

Scholars have connected this political view with Diderot's materialism. If all human beings have the same kind of living and feeling body, they also share the same basic needs. Diderot believed that they should therefore have the same basic rights and be judged by the same moral rules. These needs and rights do not depend on social rank, title or nationality.

Diderot rejected the popular idea of the "good despot", an all-powerful ruler who uses his power wisely. He argued that even a good absolute ruler teaches people to obey. After several good rulers, a nation might forget the value of freedom completely.

He defended freedom of the press and argued that people who were oppressed too greatly had a right to resist. He also condemned colonial conquest and slavery. His advice to Catherine II repeated the same general idea: rulers should give people laws, education and rights, and should give up the power to take those rights away.

Beauty and art

In the Encyclopédie article "Beau" (Beautiful), Diderot tried to explain beauty. He argued that people call something beautiful when they see "relations" in it: parts that fit together in an order that the mind can understand.

The beginning of this idea already appeared in his book about Shaftesbury in 1745. For Diderot, moral beauty and physical beauty affect people in similar ways because both depend on relations that the mind can recognize.

People have different knowledge, experience and habits, so their tastes are also different. Diderot therefore believed that beauty could be real while judgments about beauty could change between people and through history.

As an art critic, Diderot wanted art to show truth and encourage good feelings and actions. He wanted painting and theater to show real life and to move people towards what he considered good.

This led him to praise painters such as Greuze, whose pictures joined strong feelings with moral subjects, and to attack decorative painters such as Boucher. Diderot also helped to create a new, direct way of writing about art. His art criticism is still read by both artists and scholars.

Why many of his books appeared only after his death

Almost every work by which Diderot is famous today, Rameau's Nephew, Jacques the Fatalist, The Nun, D'Alembert's Dream, the Paradox of the Actor, the Salons, the letters to Sophie, was unknown to the public when he died. His contemporaries knew the editor of the Encyclopédie and the author of a few early books. Many of the works for which he is now best known remained in manuscript.

There were three reasons. After Vincennes, he did not want to give the state a reason to imprison him again. For twenty years, any new scandal signed "Diderot" could have endangered the Encyclopédie. And he wrote for the future, reworking his texts endlessly and reading them only to a small circle, or sent them to the few royal readers of Grimm's handwritten newsletter.

After 1784 the manuscripts survived in three main sets: the set sent to Saint Petersburg, the set kept by his daughter, and the papers of Naigeon. From these sources the hidden works came out slowly: The Nun and Jacques the Fatalist in 1796, a large edition by Naigeon in 1798, Rameau's Nephew in German in 1805 and in French in 1823, D'Alembert's Dream and the Paradox of the Actor in 1830, the complete letters to Sophie Volland only in the 20th century. In 1948 scholars gained access to the family's collection of manuscripts, now in the National Library of France. A much fuller picture of Diderot's work therefore became possible only about 150 years after his death.

Legacy

The statue of Diderot in Langres, made by Bartholdi, soon after it was put up (1885).

In Germany his effect came first. The playwright Lessing built on his theater ideas, Goethe translated Rameau's Nephew, and the philosopher Hegel placed a long analysis of the Nephew in one of his major books. Karl Marx, asked in a family game to name his favorite prose writer, answered: Diderot.

The statue of Diderot in Paris, by Jean Gautherin (1886), photographed around 1890.

In France the 19th century slowly rediscovered him. A complete edition in twenty volumes appeared in the 1870s. Around the hundredth year after his death, statues of Diderot were put up in Langres (in 1884, by Bartholdi, the sculptor of the Statue of Liberty) and in Paris (in 1886), and the main square of Langres now carries his name.

During the 20th century, the publication and study of his manuscripts greatly changed his reputation. They revealed a body of work close to modern concerns: a materialist biology before Darwin, a self-aware novel before the moderns, an early criticism of colonialism. His books have inspired plays and films, and writers such as Milan Kundera have claimed him as an ancestor.

Diderot research is now international. In 1983 a first large scholarly meeting at Cerisy, in France, was devoted to interpreting his work. A second one, in 2020, examined his moral thought. A complete critical edition of everything Diderot wrote, begun in Paris in 1975, is still in progress. In a study published in 2021, the German scholar Hans Ulrich Gumbrecht read Diderot as a writer at the periphery of the Enlightenment, more interested in chance and singular detail than in systems of reason.

Two stories about him have been corrected by historians. The portrait painted by Louis-Michel van Loo in 1767, which hangs in the Louvre and illustrates most books about him, did not please its model: Diderot wrote that it made him look like an old flirt, and warned his grandchildren that he never really looked like that. And a well-known anecdote, according to which the mathematician Euler silenced Diderot at the Russian court with a fake algebra formula proving God, appears nowhere in the sources of the time; historians have shown that the story is a later invention.

The Maison des Lumières Denis Diderot in Langres, opened in 2013.

The monument to Diderot and the encyclopedists inside the Panthéon in Paris, by Alphonse-Camille Terroir.

Today, schools, streets and squares across France are named after Diderot. A Paris university, Paris Diderot (Paris 7), carried his name from 1994 until it merged into the new Université Paris Cité in 2020. In 2013, for the 300th year after his birth, France held national celebrations, and Langres opened a museum about him and his century, the Maison des Lumières Denis Diderot. There have been proposals to move his remains to the Panthéon, the burial place of French national heroes; since his remains are lost, this has not been done.

Selected works

Plays:

• Le Fils naturel (The Natural Son), 1757
• Le Père de famille (The Father of the Family), 1758
• Est-il bon ? Est-il méchant ? (Is He Good? Is He Bad?), written about 1781, published 1834

Novels and stories:

• Les Bijoux indiscrets (The Indiscreet Jewels), 1748
• La Religieuse (The Nun), written from 1760, published 1796
• Le Neveu de Rameau (Rameau's Nephew), written about 1761 to 1780, published in German in 1805 and in French in 1823
• Jacques le fataliste et son maître (Jacques the Fatalist and His Master), written from about 1771, published 1796
• Supplément au voyage de Bougainville (Supplement to Bougainville's Voyage), written 1772, published 1796
• Les Deux Amis de Bourbonne (The Two Friends from Bourbonne) and Entretien d'un père avec ses enfants (Conversation of a Father with His Children), 1770, published 1773

Philosophy and science:

• Essai sur le mérite et la vertu (Essay on Merit and Virtue), after Shaftesbury, 1745
• Pensées philosophiques (Philosophical Thoughts), 1746
• Lettre sur les aveugles (Letter on the Blind), 1749
• Lettre sur les sourds et muets (Letter on the Deaf and Mute), 1751
• Pensées sur l'interprétation de la nature (Thoughts on the Interpretation of Nature), 1753
• Le Rêve de d'Alembert (D'Alembert's Dream), written 1769, published 1830
• Paradoxe sur le comédien (The Paradox of the Actor), written in the 1770s, published 1830
• Entretien d'un philosophe avec la maréchale de *** (Conversation of a Philosopher with the Marshal's Wife), written 1774, printed 1777 without his name
• Réfutation d'Helvétius (Refutation of Helvétius), written about 1773 to 1776, published 1875
• Éléments de physiologie (Elements of Physiology), written 1774 to 1784, published 1875

Criticism, politics and other works:

• Encyclopédie (Encyclopedia), 17 volumes of text and 11 of pictures, 1751 to 1772, as chief editor and author of thousands of articles
• Éloge de Richardson (In Praise of Richardson), 1762
• Salons (reviews of the Paris art exhibitions), written 1759 to 1781, published in stages from 1795
• Essais sur la peinture (Essays on Painting), written 1765, published 1795
• Secret contributions to the abbé Raynal's Histoire des deux Indes (History of the Two Indies), 1770s
• Essai sur les règnes de Claude et de Néron (Essay on the Reigns of Claudius and Nero), 1782
• Letters to Sophie Volland, written 1759 to 1774, published from 1830

Notes and references

The notes give the author, the year of the book and the page. Full details of every book are in the next section.

Books used to write this article

• Barker, Joseph Edmund (1941). Diderot's Treatment of the Christian Religion in the Encyclopédie. New York: King's Crown Press.
• Behets, Armand (1944). Diderot critique d'art (in French). Brussels: Éditions Lumière.
• Bourdin, Jean-Claude (1998). Diderot et le matérialisme (in French). Paris: Presses Universitaires de France.
• Cresson, André (1949). Diderot: sa vie, son œuvre, avec un exposé de sa philosophie (in French). Paris: Presses Universitaires de France.
• Cru, R. Loyalty (1913). Diderot as a Disciple of English Thought. New York: Columbia University Press.
• Curran, Andrew S. (2019). Diderot and the Art of Thinking Freely. New York: Other Press. ISBN 9781635420395.
• Duflo, Colas (2013). Diderot. Du matérialisme à la politique (in French). Paris: CNRS Éditions. ISBN 9782271076588.
• Fontenay, Élisabeth de (1981). Diderot ou le matérialisme enchanté (in French). Paris: Grasset. ISBN 9782246230519.
• Fontenay, Élisabeth de; Proust, Jacques, eds. (1984). Interpréter Diderot aujourd'hui (in French). Paris: Le Sycomore.
• Furbank, P. N. (1992). Diderot: A Critical Biography. London: Secker and Warburg. ISBN 9780436168536.
• Gumbrecht, Hans Ulrich (2021). Prose of the World: Denis Diderot and the Periphery of the Enlightenment. Stanford: Stanford University Press. ISBN 9781503615250.
• Lojkine, Stéphane; Paschoud, Adrien; Selmeci Castioni, Barbara, eds. (2016). Diderot et le temps (in French). Aix-en-Provence: Presses Universitaires de Provence. ISBN 9791032000526.
• O'Gorman, Donal (1971). Diderot the Satirist: Le Neveu de Rameau and Related Works. Toronto: University of Toronto Press.
• Peretz, Eyal (2013). Dramatic Experiments: Life According to Diderot. Albany: State University of New York Press. ISBN 9781438448022.
• Proust, Jacques (1995) [First published 1962, Paris: Armand Colin]. Diderot et l'Encyclopédie (in French). Paris: Albin Michel.
• Quintili, Paolo (2001). La pensée critique de Diderot: matérialisme, science et poésie à l'âge de l'Encyclopédie (in French). Paris: Honoré Champion. ISBN 9782745304230.
• Richard, Odile; Stenger, Gerhardt, eds. (2022). Les Morales de Diderot (in French). Paris: Hermann. ISBN 9791037019608. Papers of the second Cerisy meeting on Diderot, held in 2020.
• Stenger, Gerhardt (2013). Diderot: le combattant de la liberté (in French). Paris: Perrin. ISBN 9782262036331.
• Trousson, Raymond (2007). Diderot. Folio biographies (in French). Paris: Gallimard.
• Vandeul, Marie-Angélique de (1830) [Written 1787]. Mémoires pour servir à l'histoire de la vie et des ouvrages de Diderot (in French). Paris. The memoir written by Diderot's daughter.
• Walters, Gordon B., Jr. (1971). The Significance of Diderot's Essai sur le mérite et la vertu. Chapel Hill: University of North Carolina Press. ISBN 9780807891124.{{cite book}}: CS1 maint: multiple names: authors list (link)
• Wilson, Arthur M. (1985) [First published in English as Diderot, New York: Oxford University Press, 1972]. Diderot, sa vie et son œuvre. Bouquins (in French). Paris: Laffont-Ramsay. ISBN 9782221046616. Page numbers refer to the French edition.

Related pages

• Encyclopédie
• Jean le Rond d'Alembert
• Voltaire
• Jean-Jacques Rousseau
• Paul-Henri Thiry, Baron d'Holbach
• Age of Enlightenment
• Catherine the Great
• Atheism
• Materialism

Other websites

• Works by Denis Diderot at French Wikisource (in French)
• Works by or about Denis Diderot at the Internet Archive
• The full text of the Encyclopédie online (ARTFL project, University of Chicago)