Denis Diderot, born in 1713 in Langres, is resulting from a family of easy craftsmen. Though raises undisciplined, it makes brilliant studies among Jesuits, in his birthplace, then in Paris, as from 1729. After its control be arts, in 1732, it chooses the literary career.

A work polemizes
The Letter on the blind men with the use of those which see (1749) constitutes the first philosopher's stone materialist of Diderot. Criticizing the assertion of René Descartes on the existence of innate ideas in the man, independently of any experiment, Diderot accepts the theses developed by the English philosopher John Locke in her philosophical Test relating to the human understanding and taken again by Condillac. For them, any idea comes from the directions: “There is nothing in the understanding which was not before in the directions.” The Letter on the blind men leaves the “problem of Molyneux”, that the operation of a person blind from birth by the English surgeon Cheselden in 1728 had returned topicality: would a person blind from birth who can distinguish a cube from a sphere by the touch be able to distinguish them in the same way by the sight? For Diderot, the person blind from birth, Saunderson, become a denial inflicted Providence, and the monster following the example of even which calls into question the concept of order and perfection in nature. The Letter is completed in daydream on the history of the nature, unceasingly subjected to transformations and various vicissitudes: the movement appears thus essential with the matter. The boldness of these ideas materialists will show a imprisonment of a few months with Vincennes. The test will durably mark Diderot, which will have from now on to give up publishing part of its works (some will appear more than one half-century after its death) or ruser: in the Encyclopedia, the play of the references helps the reader but also thwarts the censure.

The adventure of the Encyclopedia

An assessment of the technical knowledge
Engaged since several years in the edition of the Encyclopedia, or reasoned Dictionary of sciences, arts and the trades, with Alembert for the mathematical part, Diderot is in charge of a colossal collective company. Critical assessment of the accumulated knowledge and examination of the efforts to make to make knowledge useful, the Encyclopedia does not propose anything less than one new manner of thinking and of making think, removed of the prejudices and the tradition. Diderot, which grants a broad place to sciences and the “mechanical arts” in the Dictionary, meets craftsmen to be able to describe their trade correctly and to make carry out boards representing the machines and their use, subjects to the criticism of the reason all the opinions.

A tool of reflection
Thus it forges a new ideal of man, who incarnates himself in the figure of the philosopher, “honest man who acts in all by the reason, and which joint with a spirit of reflection and accuracy sociable manners and qualities”. Man in the city, the philosopher, character familiar of the dialogs of Diderot, challenges the idea of monarchy of divine right, and defines the terminals of any power. In the article “Political authority” of the Encyclopedia, he writes: “No man received nature the right to order the others. Freedom is one present of the sky and each individual of the same species has the right to enjoy it at once that he enjoys the reason.” Reflections policy, philosophical and scientific go hand in hand in the encyclopedic company, so that it is violently attacked, and its impression suspended of 1758 to 1765. But Diderot will continue work, one of the principal instruments of diffusion of the Lights. Its work Of the interpretation of nature (1753) constitutes a reflection on the relationship between science and policy, and one of the first statements of experimental method.  

The experiment of the theater

Except for the writings for the theater and of articles of the Encyclopedia, mutilated without its knowledge by its bookseller out of fear of the censure, most works of Diderot according to 1753 will be published well after its death. Creator of the “middle-class drama”, Diderot, with the natural Son (1757) and the Father (1758), intends to reform the theater and the conditions of the stage performance. Considering it impossible to perpetuate the traditional theater of the XVII E century, it creates characters whose “conditions” and the situations are of its century. Against the solidified declamations, he preaches a controlled play, resting on the judgment and not the sensitivity (its Paradox on the actor will occupy it of 1769 at the end of its life), passing by gestures, mimes, a body presence which contributes to make direction. In his theoretical works on the theater, in particular the Talks on “the natural Son” and Speech on the dramatic poetry (which accompanies the Father), this admiror of Shakespeare and Molière but also of the energy and the simplicity of the Greek theater recommends the return to the naturalness, who is not the simple imitation of nature, but rather the realization of a “ideal model”, aiming “making the odious virtue pleasant and defect” and thus at reforming the company. Paradoxically, the theater of Diderot is played little, whereas several novels or philosophical, which leave a broad place to the dialog, were carried to the scene, like the Nephew of Branch (1762-1772, published in 1891).

Living rooms and art critic

Started at the request of his/her friend Grimm for the literary Correspondence, intended for some crowned heads of Europe, the Living rooms, of 1759 to 1781, represent the invention of a kind. Diderot gives an account of the exposed tables: it is at the same time a question of describing the scenes or the situations, of making seize the technique of the painter and of expressing the felt emotion. At the same time as he invents a language to speak about the scrambled ciels of Vernet, or the poetic one of the ruins of Hubert Robert, to penetrate in the pathetic one of the intimate scenes of Greuze, or to make feel the evolution of the painting of its time - atmosphere of the gallant festivals of Regency to David -, Diderot reflects on the relationship between poetry and painting; by the writing, it sometimes happens to him to rebuild the tables to give them more energy. Prefiguration of the romanticism, its designs of the art, according to which it must correspond to its time, grant a role particular to the sensitivity and the genius, for which are appropriate the disturbed times: “Poetry wants something of enormous, barbarian, savage.”  
 
Universal sensitivity

For Diderot, “food, it is to feel”, and the sensitivity, which unifies the physique and the moral one, plays a crucial role in its materialism: the least alive fiber reacts to the external impressions, by the movement or the feeling, but to differing degrees; it can be presented in a latent, numb form - it is the “sensitivity deaf or inert” -, or in an active form, the passage of the one with the other being done by unperceivable nuances. “The thought is the result of the sensitivity, which is a universal property of the matter”, he in a letter with Duclos in 1765 writes. These ideas, in particular exposed in the Dream of Alembert and the philosophical Principles on the matter and the movement, however do not lead to a reducing materialism: Diderot is conscious that a living being, a fortiori a man, do not bring back themselves to a sum of alive and sensitive molecules. He seeks to conceive the passage of the part to the whole, to find a model expressing this total point of view, synthetic, which defines an organization: it is what it expresses by the comparison of the swarm of bees, where each living being, just as each body or each molecule, contributes, either by adjacency, or by continuity, with the life of the unit.

The novelist and the épistolier

The originality of Diderot novelist bursts less in the Nun than in Jacques the fatalist, who founds a modern romantic writing, where the levels of account overlap, where the authorities of stating multiply - characters becoming narrators - and where digressions compared to the central theme, unceasingly announced and unceasingly differed (the account of the loves of Jacques), constitute the essence of the novel. Stopping the narrative screen to take with part the reader, Diderot draws up a subtle relationship between the freedom of the writing and the topic of fatalism, that Jacques expresses by affirming that all is written up there “in the large roller”.

One knows no letter of that which Diderot immortalized like “my Sophie”, in a correspondence maintained until death the two lovers, in a few months of interval, in 1784. The Letters with Sophie Volland sign the strange power of the absence, the presence of this quiet voice, confidante of the thoughts of the philosopher. Their impassioned accents leave a trace which is perhaps this form of survival of the molecules after the death desired by Diderot, the poetry of a memory of the matter.

Diderot and enlightened despotism

In spite of its voyage in Russia and generosity that the empress Catherine II proclamation in her connection (purchase of its library before its death, pension), Diderot was less than other victim of the illusions of the lit despotism, whose criticism is confirmed in texts like the Supplement with the “Voyage of Bougainville”, where are analyzed the relationship between nature and social life; in the Plan of a university for the government of Russia, which it sends to Catherine II in 1775, it exposes a democratic design of the instruction. Its collaboration with the History of the two Indies, of the Raynal abbot, mark also of the very critical standpoint with regard to slavery and of the economic wheels that Europe sets up in its relations with the other countries of the world.