Denis Diderot (October 5, 1713 – July 31, 1784) was a French philosopher and writer. He was a prominent figure in the Enlightenment, and editor-in-chief of the famous Encyclopédie.

Diderot also contributed to literature, notably with Jacques le fataliste et son maître (Jacques the Fatalist and His Master), which emulated Laurence Sterne in challenging conventions regarding novels, their structure and content, while also examining philosophical ideas about free will. Diderot is also known as the author of the essay, "Regrets on Parting with My Old Dressing Gown," upon which many an article and sermon about consumer desire has been based.

Diderot was born in the eastern French city of Langres and commenced his formal education in the Jesuit School. In 1732, he earned a master of arts degree in philosophy. He abandoned the idea of entering the clergy and decided instead to study law. His study of the law, however, was short-lived. In 1734, Diderot decided instead to become a writer. Because of his refusal to enter one of the learned professions, he was disowned by his father, and for the next ten years he lived a rather bohemian existence. In 1743, he further alienated his father by marrying Antoinette Champion, a devout Roman Catholic. The match was considered inappropriate because of Champion's low social status, poor education, fatherless status, lack of a dowry, and at thirty-two she was four years his senior. The marriage produced one surviving child, a girl. She was named Angelique after Diderot's mother and his dead sister. The death of his sister, a nun, from overwork in the convent may have affected Diderot's opinion of religion.

He had affairs with the writer Madame Puisieux and with Sophie Volland, to whom he was constant for the rest of her life. His letters to her are among the most graphic of all the pictures that we have of the daily life of the philosophic circle in Paris.

Though his work was broad and rigorous, it did not bring him riches. He secured none of the posts that were occasionally given to needy men of letters; he could not even obtain that bare official recognition of merit which was implied by being chosen a member of the Académie française. When the time came for him to provide a dowry for his daughter, he saw no alternative than to sell his library. When Catherine II of Russia heard of his straits, she commissioned an agent in Paris to buy the library, and then requested that the philosopher retain the books in Paris until she required them, and act as her librarian with a yearly salary. In 1773 and 1774, Diderot spent some months at the empress's court at St Petersburg.

He died of emphysema in Paris on July 31, 1784, and was buried in the city's Eglise Saint-Roch. His heirs sent his vast library to Catherine II, who had it deposited at the Russian National Library.

Diderot's earliest works included a translation of Stanyan's History of Greece (1743); with two colleagues, François-Vincent Toussaint and Marc-Antoine Eidous, he produced a translation of Robert James's Medical Dictionary (1746–1748) and about the same date he published a free rendering of Shaftesbury's Inquiry Concerning Virtue and Merit (1745), with some original notes of his own. In 1746, he wrote his first original work: the Pensées philosophiques , and he presently added to this a short complementary essay on the sufficiency of natural religion. He composed a volume of bawdy stories, Les bijoux indiscrets (1748); in later years he repented of this work. In 1747, he wrote the Promenade du sceptique, an allegory pointing first at the extravagances of Catholicism; second, at the vanity of the pleasures of that world which is the rival of the church; and third, at the desperate and unfathomable uncertainty of the philosophy which professes to be so high above both church and world.

Diderot's next piece introduced him to the world as an original thinker, his famous Lettre sur les aveugles (1749). The immediate object of this short work was to show the dependence of men's ideas on their five senses. It considers the case of the intellect deprived of the aid of one of the senses; and in a second piece, published afterwards, Diderot considered the case of a similar deprivation in the deaf and mute. The Lettre sur les sourds et muets, however, is substantially a digressive examination of some points in aesthetics. The philosophic significance of the two essays is in the advance they make towards the principle of relativism. But what interested the militant philosophers of that day was an episodic application of the principle of relativism to the concept of God. What makes the Lettre sur les aveugles interesting is its presentation, in a distinct though undigested form, of the theory of variation and natural selection. It is worth noticing, too, as an illustration of the comprehensive freedom with which Diderot felt his way round any subject that he approached, that in this theoretic essay he suggests the possibility of teaching the blind to read through the sense of touch.

His speculation in the Lettre sur les aveugles was too hardy for the authorities, and he was thrown into the prison of Vincennes. Here he remained for three months; then he was released, to enter upon the gigantic undertaking of his life.

The bookseller and printer André Le Breton had applied to Diderot with a project for the publication of a translation into French of Ephraim Chambers' Cyclopaedia, or Universal Dictionary of Arts and Sciences, undertaken in the first instance by the Englishman John Mills, and the German, Gottfried Sellius. Diderot accepted the proposal, but in his busy and pregnant intelligence the scheme became transformed. Instead of a mere reproduction of the Cyclopaedia, he persuaded Le Breton to enter upon a new work, which should collect under one roof all the active writers, all the new ideas, all the new knowledge, that were then moving the cultivated class of the Republic of Letters to its depths, but still were comparatively ineffectual by reason of their dispersion.

His enthusiasm infected the publishers; they collected a sufficient capital for a vaster enterprise than they had at first planned; Jean le Rond d'Alembert was persuaded to become Diderot's colleague; the requisite permission was procured from the government; in 1750 an elaborate prospectus announced the project to a delighted public; and in 1751 the first volume was given to the world. The last of the letterpress was issued in 1765, but it was 1772 before the subscribers received the final volumes of the Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers.

Plagued by controversy from the beginning, the project was suspended by the courts in 1752. Just as the second volume was completed, accusations arose regarding seditious content concerning the editors entries on religion and natural law. Diderot was detained and his house was searched for manuscripts for subsequent articles. But the search proved fruitless as the manuscripts could not be found. They were being hidden in the house of an unlikely confederate-Chretien de Lamoignon Malesherbes, the very official who ordered the search. Although Malesherbes was a staunch absolutist-loyal to the monarchy, he was sympathetic to the literary project. Along with his support, and that of other well placed, influential confederates, the project resumed. Diderot returned to his efforts only to be constantly embroiled in controversy.

These twenty years were to Diderot not merely a time of incessant drudgery, but of harassing persecution and of injury from the desertion of friends. The ecclesiastical party detested the Encyclopédie, in which they saw a rising stronghold for their philosophic enemies. By 1757 they could endure it no longer. The subscribers had grown from 2,000 to 4,000, a measure of the growth of the work in popular influence and power. The Encyclopédie threatened the governing social classes of France (aristocracy) because it took for granted the justice of religious tolerance, freedom of thought, and the value of science and industry. It asserted the democratic doctrine that the main concern of the nation's government ought to be the nation's common people.

It was believed that the Encyclopédie was the work of an organized band of conspirators against society, and that the dangerous ideas they held were made truly formidable by their open publication. In 1759, the Encyclopédie was formally suppressed. The decree, however, did not stop the work, which went on, but its difficulties increased by the necessity of being clandestine.

D'Alembert withdrew from the enterprise and other powerful colleagues, including Anne Robert Jacques Turgot, Baron de Laune, declined to contribute further to a book which had acquired a bad reputation. Diderot was left to bring the task to an end as best he could. He wrote several hundred articles, some very slight, but many of them laborious, comprehensive and long. He damaged his eyesight in correcting proofs and in editing the manuscripts of less competent contributors. He spent his days at workshops, mastering manufacturing processes, and his nights in reproducing on paper what he had learned during the day. He was incessantly harassed by threats of police raids.

At the last moment, when his immense work was drawing to an end, he encountered a crowning mortification: he discovered that the bookseller, fearing the government's displeasure, had struck out from the proof sheets, after they had left Diderot's hands, all passages that he considered too dangerous. The monument to which Diderot had given the labor of twenty long and oppressive years was irreparably mutilated and defaced.

Although the Encyclopédie was Diderot's monumental work, he was the author of many pieces that sowed nearly every field of intellectual interest with new and fruitful ideas. He wrote sentimental plays, Le Fils naturel (1757) and Le Père de famille (1758), accompanying them with essays on theatrical theory and practice, including especially Les Entretiens sur Le Fils naturel (Conversations on Le Fils naturel), in which he announced the principles of a new drama—the serious, domestic, bourgeois drama of real life, in opposition to the stilted conventions of the classical French stage.

His art criticism was also highly influential. His Essais sur la peinture were described by Johann Wolfgang von Goethe, who thought it worth translating, as "a magnificent work, which speaks even more helpfully to the poet than to the painter, though to the painter too it is as a blazing torch."

Diderot's most intimate friend was the philologist Friedrich Melchior Grimm who were brought together by their friend in common at that time Jean-Jacques Rousseau. Grimm wrote newsletters to various high personages in Germany, reporting what was going on in the world of art and literature in Paris, then the intellectual capital of Europe. Diderot helped Grimm between 1759 and 1779, by writing an account of the annual exhibitions of paintings in the Paris Salon. These reports are highly readable pieces of art criticism. According to Charles Augustin Sainte-Beuve, they initiated the French into a new way of thinking, and introduced people to the mystery and purport of colour by ideas. "Before Diderot," Anne Louise Germaine de Staël wrote, "I had never seen anything in pictures except dull and lifeless colours; it was his imagination that gave them relief and life, and it is almost a new sense for which I am indebted to his genius."

Jean-Baptiste Greuze was Diderot's favorite contemporary artist. Greuze's most characteristic pictures were the rendering in colour of the same sentiments of domestic virtue and the pathos of common life, which Diderot had attempted to represent upon the stage. For Diderot was above all things interested in the life of individuals, not the abstract life of the race, but the incidents of individual character, the fortunes of a particular family, the relations of real and concrete motives in this or that special case. He delighted with the enthusiasm of a born casuist in curious puzzles of right and wrong, and in devising a conflict between the generalities of ethics and the conditions of an ingeniously contrived practical dilemma. Diderot's interest expressed itself in didactic and sympathetic form.

However, in two of his most remarkable pieces, this interest is not sympathetic, but ironic. Jacques le fataliste (written in 1773, but not published until 1796) is similar to Tristram Shandy and The Sentimental Journey. His dialogue Le Neveu de Rameau (Rameau's Nephew) is a "farce-tragedy" reminiscent of the Satires of Horace. A favorite classical author of Diderot's, Horace's words Vertumnis, quotquot sunt, natus iniquis are quoted at the top of the Nephew. Diderot's intention in writing the dialogue is disputed; whether it is merely a satire on contemporary manners, or a reduction of the theory of self-interest to an absurdity, or the application of irony to the ethics of ordinary convention, or a mere setting for a discussion about music, or a vigorous dramatic sketch of a parasite and a human original. Whatever its intent, it is a remarkable conversation, representing an era of that held the art of conversation in the highest regard. The writing and publication history of the Nephew is likewise a bit mysterious. Diderot never saw the work through to publication during his lifetime, but there is every indication it was of continual interest to him. Though the original draft was written in 1761, he made additions to it year after year until his death twenty-three years later. Goethe's translation (1805) was the first introduction of Le Neveu de Rameau to the European public. After executing it, he gave back the original French manuscript to Friedrich Schiller, from whom he had it. No authentic French copy of it appeared until the writer had been dead forty years (1823).

Diderot's miscellaneous pieces range from a graceful trifle like the Regrets sur ma vieille robe de chambre up to Le Rêve de d'Alembert, where he plunges into the depths of the controversy as to the ultimate constitution of matter and the meaning of life. Diderot was not a coherent and systematic thinker, but rather "a philosopher in whom all the contradictions of the time struggle with one another" (Rosenkranz). He did not develop a system of materialism, but he contributed many of the most declamatory pages of the Système de la nature of his friend Paul Henri Thiry, baron d'Holbach, styled by some "the very Bible of atheism".

*"And his hands would plait the priest's entrails, for want of a rope, to strangle kings." *"I have been, and still am, angry at being mediocre." *Enlightenment thinkers, as Diderot wrote, intended "to change the common way of thinking" *"Man will never be free until the last king is strangled with the entrails of the last priest." *"Only passions, great passions can elevate the soul to great things." *"The arbitrary rule of a just and enlightened prince is always bad. His virtues are the most dangerous and the surest form of seduction: they lull a people imperceptibly into the habit of loving, respecting, and serving his successor, whoever that successor may be, no matter how wicked or stupid." *"There are little testicles at the bottom of our most sublime feelings and our purest tenderness." ("Il y a un peu de testicule au fond de nos sentiments les plus sublimes et de notre tendresse la plus épurée") Letter to Damilaville 3 November 1760

*Atheism *Contributions to liberal theory *Encyclopedia *Encyclopedist *Liberalism *University of Paris VII: Denis Diderot

* Essai sur le mérite et la vertu, written by Shaftesbury French translation and annotation by Diderot (1745) * Pensées philosophiques, essay (1746) * La promenade du sceptique (1747) * Les bijoux indiscrets, novel (1748) * Lettre sur les aveugles à l'usage de ceux qui voient (1749) * L'''Encyclopédie, (1750-1765) * Lettre sur les sourds et muets (1751) * Pensées sur l'interprétation de la nature, essai (1751) * Le fils naturel (1757) * Entretiens sur le Fils naturel (1757) * Discours sur la poesie dramatique (1758) * Salons, critique d'art (1759-1781) * La Religieuse, Roman (1760) * Le neveu de Rameau, dialogue (1761?) * Lettre sur le commerce de la librairie (1763) * Mystification ou l’histoire des portraits (1768) * Entretien entre D'Alembert et Diderot (1769) * Le rêve de D'Alembert, dialogue (1769) * Suite de l'entretien entre D'Alembert et Diderot (1769) * Paradoxe sur le comédien (1769?) * Apologie de l'abbé Galiani (1770) * Principes philosophiques sur la matière et le mouvement, essai (1770) * Entretien d'un père avec ses enfants (1771) * Jacques le fataliste et son maître, novel (1771-1778) * Supplément au voyage de Bougainville (1772) * Histoire philosophique et politique des deux Indes, in collaboration with Raynal (1772-1781) * Voyage en Hollande (1773) * Éléments de physiologie (1773-1774) * Réfutation d'Helvétius (1774) * Observations sur le Nakaz (1774) * Essai sur les règnes de Claude et de Néron (1778) * Lettre apologétique de l'abbé Raynal à Monsieur Grimm (1781) * Aux insurgents d'Amérique (1782) * Salons

*Furbank, P. N. Diderot: A Critical Biography. New York: A. A. Knopf, 1992. ISBN 0-679-41421-5. *Havens, George R. The Age of Ideas. New York: Holt, 1955. ISBN 0-89197-651-5. *Simon, Julia. Mass Enlightenment. Albany: State University of New York Press, 1995. ISBN 0-7914-2638-6. *Hoyt, Nellie and Cassirer, Thomas.Encyclopedia, Selections:Diderot, D'Alembert, and a Society of Men of Letters. New York: Bobbs-Merrill Company, Inc, 1965. LCCN 65-26535. ISBN 0-672-60479-5

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* *Diderot's listing at the Bibliotheque Nationale de France (in French) * The Project Gutenberg eBook of Diderot by John Morley * Short biography * Denis Diderot Bibliography * Le Neveu de Rameau - Diderot et Goethe