Philosopher and writer, b. 5 October 1713 (Langre, France), d. 31 July 1784 (Paris), editor of the Encyclopédie, ou Dictionnaire Raisonné des Sciences, des Arts et des Métiers
(Encyclopaedia, or Classified Dictionary of Sciences, Arts and Trades)
Diderot's father was a cutler. At the age of 13 the young Denis was destined to become a monk, but he did not enter an order. He was educated by Jesuits and entered the University of Paris, which awarded him a master of arts in 1732. Diderot then took up the study of law and made a living as a clerk.
Little is known about Diderot's life during the next ten years. He was obviously more interested in literature, philosophy and the sciences than law, considered a theatrical and a church career but survived through teaching and writing sermons for missionaries on demand.
It appears that as a young man Diderot underwent a religious crisis. In 1741 he had established a friendship with Jean-Jacques Rousseau, and when he surfaced into prominence in 1745 he had moved from Catholicism through deism to atheism and become a major proponent of philosophical materialism. He now made his living through translations, and the translation of the Inquiry Concerning Virtue by the 3rd Earl of Shaftsbury, published in 1745, caused him to write his own Pensées Philosophiques ("Philosophic Thoughts"), which he published in 1746.
The translation of Shaftsbury's work had shown Diderot as a capable translator, and soon after its publication the publisher André Le Breton asked Diderot to prepare a translation of Ephraim Chambers' Cyclopaedia. The project soon expanded into what was to become Diderot's life achievement. When the translation arrangements ran into difficulties Diderot began to devise his own plan of an encyclopaedia as a medium for radical and revolutionary ideas.
The French Revolution was still more than 40 years away, but Diderot and his co-editor the distinguished mathematician Jean Le Rond d'Alembert managed to gather a circle of enthusiastic writers, scientists and even priests, most of them yet unknown, who were prepared to put together a document of rationalism and faith in the progress of human thought.
The planned Encyclopédie faced problems from its beginnings. Ironically its first setback was caused not by the project itself but by an independent publication. In 1749 Diderot published the Lettre sur les aveugles ("An Essay on Blindness"), in which he developed the idea of teaching the blind to read through the sense of touch. It was essentially the same idea followed by Louis Braille a century later. But for Diderot it was also an example of the idea of survival through adaptation, and his materialist atheism got him into prison for three months.
As soon as he was released Diderot developed his Prospectus for the encyclopaedia, which d'Alembert expanded into the Discours préliminaire in 1751, a declaration of purpose that defined the battle lines for the years to come. Under Diderot's energetic editorship the project survived a total ban and multiple attempts of censorship.
His role as editor of a work of momentous proportions did not stop Diderot from publishing original work himself. He contributed a large number of articles to the Encyclopédie, particularly on the history of philosophy, social theory and aesthetics under the entries Eclectisme ("Eclecticism"), Droit Naturel ("Natural Law") and Beau ("The Beautiful"). In 1751 he published the Lettre sur les sourds et muets ("Letter on the Deaf and Dumb") and three years later the Pensées sur l'interprétation de la nature ("Thoughts on the Interpretation of Nature"), a discussion on the new experimental basis of science.
The completion of the Encyclopédie in 1772 forced Diderot to find other means of financial support. He was assisted by empress Catherine the Great of Russia, who initially bought his library under the condition that he could keep it until she required it and later gave him an annual salary for life as librarian of his own collection. Diderot travelled to St. Petersburg in 1773 to thank her and wrote a Plan d'une université pour le gouvernement de Russie ("Plan of a University for the Government of Russia") but left again for Paris after five months, disillusioned with a society under enlightened despotism.
Diderot died in a house provided to him by Catherine the Great. After intervention of his son-in-law with the authorities he was allowed to be buried in consecrated ground.
Diderot's material philosophy naturally led him to write on many aspects of life, but most of his works were only published after his death, and his fame grew as his writings became known. Diderot contributed regularly to the periodical Correspondence littéraire and can be regarded the first professional art critic. Among his many works are
Philosophical writings
Prose fiction
Plays and theatrical and aesthetic theory
Niklaus, R. (1995) Denis Diderot. Encyclopaedia Britannica 15th ed.