Diderot's Encyclopédie

The story

A mad project

Imagine a book that wants to hold everything: how a clock works, how glass is made, what the stars are, how bread is baked, what the rules of chess are, how to write a letter. In the 18th century some people really wanted to do this. The project began with a Parisian publisher, André Le Breton, who in 1745 wanted to translate into French a great English work, Ephraim Chambers's “Cyclopaedia”, a dictionary of the arts and sciences. But the undertaking changed scale when it was handed to two young men: the writer Denis Diderot and the mathematician Jean le Rond d'Alembert.

Diderot, the son of a cutler from Langres, was brilliant, passionate and full of ideas. He had already spent a few months in prison for his writings, which were thought too daring. D'Alembert, the illegitimate son of a noblewoman, was a famous mathematician and physicist, but also a great writer. They decided not to stop at translating: they wrote a new work, an “Encyclopédie, or Reasoned Dictionary of the Sciences, Arts and Trades”, that would gather all the knowledge of the age.

Knowledge for everyone

The first volume came out in 1751. In the “Preliminary Discourse”, d'Alembert explained the idea: knowledge is like a great tree, with roots in memory, reason and imagination, from which spring the branches of history, philosophy and the arts. But the Encyclopédie was not only for scholars: it wanted to teach everyone, so that anyone could understand the world.

A great novelty was its attention to trades. Diderot went into workshops and workrooms, talked with craftsmen and watched how they worked. The work gave long entries and splendid illustrated plates to how iron, silk and paper are worked, how a pin is made, how a ship is built. For the first time manual work was considered worth studying, alongside philosophy and theology. In all, seventeen volumes of text and eleven of plates were published, with thousands of illustrations, between 1751 and 1772.

A team of great names

Diderot and d'Alembert did not do everything alone. More than a hundred and forty contributors took part in writing the entries: Voltaire, Montesquieu and Rousseau wrote articles, and with them doctors, engineers, craftsmen, nobles and priests. The work was enormous, and Diderot, who after a few years was left almost alone in charge of the enterprise, laboured for more than twenty years, with great effort.

Censorship and courage

The Encyclopédie made the people in power furious. It explained things by reason and experience, not by the authority of tradition and religion. It criticised privileges, superstition and intolerance, and the Church saw it as a danger. In 1752 the government banned it, in 1759 a Parliament authority condemned it, and the Pope put it on the list of forbidden books. Diderot had to work almost in secret, and some entries were written cautiously, or with ironic cross-references from one entry to another.

According to tradition, a friend, the head of censorship, Malesherbes, warned Diderot before a search, and the manuscripts were hidden in his father's house, the very last place anyone would suspect. D'Alembert, tired of quarrels, left the project in 1758. In the end, in 1772, the work was completed.

Success

In spite of everything, the Encyclopédie was a huge success. About twenty-five thousand copies were sold across Europe, a very high figure for such an expensive work, and further editions and reprints were made, in Italy and Switzerland too, at lower prices. The people who read it were not only nobles and scholars, but also merchants, lawyers and doctors.