Denis Diderot
Denis Diderot; drawing by David Levine

The eighteenth century is remote enough to be another world, yet near enough for us to recognize here in their infancy our modern values, our political doctrines, and our intellectual disciplines. Exploring the eighteenth century is an indirect but useful way of examining ourselves.

In completing his biography of Diderot, Arthur M. Wilson has earned the gratitude of everyone who is interested in the Enlightenment. Diderot’s importance needs no emphasizing today. Throughout the twentieth century he has been growing steadily in stature, and critical comment on his work has even outstripped that devoted to Rousseau—no small feat. The recent publication of Diderot’s works, competently edited by Roger Lewinter, includes almost everything Diderot wrote; all that is missing from these fourteen volumes is the complete collection of texts written by Diderot for the Encyclopedia. Compiling them would have been a hard task, and it will raise daunting problems for the international team of scholars who are about to undertake a critical edition of Diderot’s works.

Diderot indeed occupies a central place in the Enlightenment. Stubborn courage enabled him to bring the great ark of the Encyclopedia safe to harbor in 1772 after twenty-five years of untiring labor. The Encyclopedia has been seen, and rightly so, as a symbol of the triumph of the bourgeois spirit; it aimed at bringing together knowledge of all kinds and harnessing it to the rational exploitation of natural resources for the common good. To use Bernard Groethuysen’s expression, it gave its readers a proprietor’s view of the world. Similarly, Diderot made a decisive contribution to almost every field he touched on. He launched aesthetics and art criticism on a new career, he was instrumental in changing the face of the theater, he invented the first experimental novels. He had an impressive insight into the tasks and methods of the new biology.

He was master enough of the learning of his age to be able to claim without exaggeration that nothing human was foreign to him; mathematics, technology, music, painting, sculpture, medicine, economics, education, and politics, all of these, in almost equal measure, were his concern as a man of letters. This expression possessed in his day a breadth of meaning which it has gradually been losing ever since. In his role as a European, too. Diderot is a central figure; he is among those who introduced, assimilated, and popularized in France Bacon, Shaftesbury, Richardson, and Sterne—and in his turn he was to influence Lessing and Goethe and leave his imprint on Hegel and his progeny.

Diderot’s biographer has a hard task. There are many documents, but they are scattered; for some periods they are plentiful, for others all too rare. Unlike Rousseau, Diderot did not go to the trouble of writing a complete autobiographical apologia; to defend his name he composed not Confessions but a Life of Seneca (1779), in which he speaks of himself only indirectly. The biographer is obliged to sift his material, organizing it patiently so as to discover a guiding thread. Arthur M. Wilson has succeeded admirably in this undertaking. His brisk and sensible book is remarkable for its clarity of outline. He gives us a great deal of information, but does not clutter his text with erudition. The specialist reader will find at the end of the book a very full critical apparatus, which together with the indexes occupies almost two hundred pages. The book is thus at the same time a pleasure to read and a definitive work which anyone working on Diderot will need to consult.

It is worth adding that Diderot is also an unruffled book; the author’s obvious sympathy for his subject never lapses into partisanship. This is not a hagiography with a hero who is never wrong. Arthur M. Wilson is not the sort of biographer who feels himself obliged to weigh up rights and wrongs; he lets facts and texts speak for themselves. His impartial account of the quarrel between Rousseau and Diderot is a model of its kind. He has the modesty to limit himself to a scrupulously faithful presentation of his subject, without thrusting his own interpretations between Diderot and us. And this method works: we are given an almost physical sensation of Diderot’s presence. It is as if we were in the same room as this energetic, immensely active man who forgets his appointments, eats too much and too quickly, and allows his ready tongue to lure him into innumerable digressions. We can easily imagine his excitement (occasionally bordering on the manic) and the eloquence which can sometimes soar to sublime heights, but remains “extremely popular” in tone and leads him, rather more often than is quite proper, to praise his own kindness, virtue, and passion for good.

One of the dominant tendencies of Diderot’s mind is his urge to discover secrets, to bring them to light, to expose them to the general gaze; his aim is to lay bare everything which is so painstakingly concealed by ignorance, hypocrisy, and falsehood. Such is the lesson which his early work The Indiscreet Jewels (1748) inculcates in its libertine and rococo fashion. The starting point of this youthful “novel” is the merry hypothesis of a magic ring which enables bystanders to hear the words spoken by a part of the female body that is not normally endowed with speech; a potentially endless succession of short narratives interspersed with commentaries lets the amused reader into secrets which decency would have kept hidden. It is the lifting of a taboo. And what we discover by way of this near-pornography is what Lockean philosophy had already taught us in more modest terms: that man falls prey to uneasiness if he does not constantly renew the sensations which give him the feeling of his own existence, that boredom lies in wait for him if he does not maintain a rapid sequence of pleasures, surprises, and occupations of every possible kind.


This is why modes of behavior and works of art inspired by Lockean psychology place so much stress on variety, unexpectedness, and inconstancy, and time comes to be experienced as a string of discontinuous moments, this being reflected in literature by occasional verse, brief tales, miscellanies, and collections of anecdotes and letters where the serious and pleasurable are mixed in an unforeseeable combination. Voltaire was a master of this technique; Diderot did no more than experiment with it. He was not the sort of man to make frequent use of the frivolous literary devices which had served his purpose in The Indiscreet Jewels. It was easy for him to do without allegory, satirical fairy tales, and fairground exoticism, but he never lost his curiosity about the life of the body, about desire and sexuality, or his taste for pulling aside the draperies and revealing the truth for all to see.

There is no denying that the reason why many of Diderot’s works are so attractive (and so provocative) is that they are largely made up of the revelation and complete exposure of an inside story. What makes The Nun (1760) such a scandalous novel? Essentially it is the sudden light which it casts on what goes on behind convent walls, the unwilling vocations, the secret illegitimate births, the disastrous physiological effects of forced chastity. It is on the body, deep down in the organism, that convent life finally leaves its mark. In his nun’s confessional tale Diderot’s penetrating medical insight shows us how illness, sexual perversion, and madness are the ultimate consequences of a refusal to obey what he calls “nature.” The reader not only sees into the cells of the convent, he gains access to the secret mechanisms of female existence (as it was understood by the medical science of the eighteenth century).

It is just the same with Rameau’s Nephew (begun in 1761); the satire here consists largely of the way Diderot uses his uninhibited bohemian hero to expose to the public gaze the secret way of the world. Driven from the rich man’s house where he has been living the life of a parasite, the nephew reveals the intrigues and hidden vices of the world of high finance; expelled, because of his impertinence, from the circles where an anti-philosophe plot is being hatched, he reveals all their most secret absurdities and crimes; he knows everything and hides nothing, and above all he flaunts his own immorality, which is so perfectly adapted to the immorality of his society.

In all these examples Diderot reveals the truth by proxy: the “jewels” confessing their own misdemeanors, the nun Suzanne Simonin telling the tale of her torments, the unruly nephew lifting the veil which hides the dinner table and boudoir of a financier living with a mediocre actress. What of the times when Diderot speaks in his own name? This is Diderot the editor of the Encyclopedia, and here again he strives to reveal and divulge secrets to the general public. To undertake a task of this size it is not enough to be spurred on by a deep hate for irrational systems of belief, not enough even to be convinced of the need for a complete inventory of the arts and sciences. It needs too a certain instinctive urge, which enables one to find pleasure in exposing what is concealed. To uncover Nature’s secrets, to capture the secrets of technology and share them with the whole world, to reinforce the written word with visual representation: these were some of Diderot’s most cherished aims.

Arthur M. Wilson gives us an illuminating quotation from a text on The History and Secret of Painting in Wax (1775) in which Diderot proclaims quite openly his passion for bringing things into the light of day and defends it in the noblest moral terms. Of course it is quite possible to accept these humanitarian arguments. But at the same time it is hard not to give equal weight to a less rational sort of motive. This is how Diderot puts it:


Nothing is more contrary to the progress of knowledge than mystery…. If it happens that an invention favorable to the progress of the arts and sciences comes to my knowledge, I burn to divulge it; that is my mania. Born communicative as much as it is possible for a man to be, it is too bad that I was not born more inventive; I would have told my ideas to the first comer. Had I but one secret for all my stock in trade, it seems to me that if the general good should require the publication of it, I should prefer to die honestly on a street corner, my back against a post, than let my fellow men suffer.

This is his constant refrain. Elsewhere we read:

We must make public both the results of our research and the means by which we have achieved them. Mere publication is not enough; it must be complete and unequivocal. Let us hasten to make philosophy more accessible. Is not nature already hidden enough without our adding a veil of mystery; is experimental science not difficult enough as it is?

In his aesthetic theory, Diderot shows the same taste for bringing everything completely into the open, the same desire to have inner life totally accessible to the eye. This is why he always gives expressiveness pride of place in his art criticism. Among painters, even though he appreciates the “magical” colors of a Chardin, he gives the highest praise to artists who can catch on canvas the high point of an emotional drama, and he is full of admiration for painters who can make every attitude, every face, and every gesture both expressive and immediately comprehensible. He always demands the fullest possible manifestation of emotion in a code or language which is that of the body itself. It is the same with the theater, which he expects to convey in full both the characters’ social position and their moral dilemmas. His social realism goes hand in hand with emotional expressionism. In the theater of his dreams the most intense moments are tableaux where gesture, originally the servant of the spoken word, finally supersedes language in the name of a more immediate, more “hieroglyphic” rendering of emotion.

These feelings which the heroes of Diderot’s “serious comedies” are all too ready to display hardly seem to correspond to the real secrets of our inner lives; in them we recognize, somewhat despondently, the old repertoire of mime laid down by the most conventional theories concerning the physical expression of the passions. Perhaps Diderot felt embarrassed when the laws of the theater obliged him to give his characters a fixed and stable identity. Conversely, he is extraordinarily successful in laying bare the “inside story” of natural forces beneath the apparent stability of individual existence. He is at his masterful best when he abandons himself to the pleasure of debunking the illusion of personal autonomy and imagines, beyond the diversity of living beings, the still more amazing diversity of atoms, all endowed with their own life and combining and recombining ad infinitum in the flux of space and time.

The ocean of matter so enthusiastically evoked in Diderot’s dialogue D’Alembert’s Dream (1769) is made up of an unimaginable number of particles, each one unique, each one possessing an elementary kind of life and impelled by a basic erotic energy which must eventually give rise to every conceivable combination of matter. What Diderot loves above all else is to reveal by an act of imaginative insight the universal force of generation which haphazardly gives birth to ephemeral and monstrous forms of life, to species capable of survival, and to strange hybrids; it is this force, aided by time and chance, that eventually produces thinking beings, men of genius, and the achievements of science.

Diderot’s evolutionism, which does not rule out the possibility of periodic returns to chaos, is bound up with a dynamic and somewhat anthropomorphic image of matter as an obstinate arriviste. He uses all his lyrical powers to sing the praises of the material world; nothing excites him more than images of the production and reproduction of life. We should remember that he was writing at a time when one of men’s greatest fears was the depopulation of the globe. This is why questions of morality and immorality give way to the claims of public utility. D’Alembert’s Dream ends on the daring and entertaining hypothesis of a hybrid race produced by cross-breeding men with goats; why condemn bestiality if it can give us a vigorous new subproletariat to do our dirty work for us? The utility principle comes first.

This image of the hybrid is a significant one. The inspiration to which Diderot owes it is itself a hybrid of intellectual insight and erotic curiosity. The continuing appeal of D’Alembert’s Dream is due to a cross-fertilization of scientific thought and cosmic lyricism. It soon becomes clear that in every field, including that of literary style, Diderot was a propagator and creator of hybrids. Of the traditional genres the only one he retained and renewed was satire. Why was this? Because satire is by definition the genre which invites and welcomes heterogeneity. Diderot excels in confusing every kind of hierarchy and blurring every kind of boundary; he is a creator of half-breeds.

Rameau’s nephew, the most typical of them all, is a rare blend of villainy and intelligence; he has surprising sensitivity and artistic ability, yet he is incapable of creating anything—he is a hybrid of talent and impotence. Jacques in Jacques the Fatalist is a mixture of intellectual superiority and social inferiority. The work named after him is a hybrid of dialogue and narration. The middle-class drama which Diderot advocated is in reality the bastard child of comedy (which was thought a “low” genre) and tragedy (which until then had been considered the only theatrical genre capable of attaining the “sublime”). It is no accident that Diderot’s first stage hero is a “natural son.” Nor should we forget that Diderot’s nun is an illegitimate daughter and that by having her write her life story in the first person Diderot is attempting the curious experiment of identifying himself with the tormented existence of a woman’s mind and body. The principle of hybridization leads to literary androgyny.

To think of man as an aggregate of living molecules; to admit the possibility of each organ having its own separate existence; to reduce the diversity between living beings simply to differences of physical organization: is not this tantamount to propounding a doctrine of implacable determinism? In this scheme of things man becomes the plaything of the various elements which make up his body—and of the chance which brought them together. If we read it to the bitter end, doesn’t his “inside story” lead us to an “outside story” where everything depends on the laws of matter?

Arthur M. Wilson’s book is very illuminating on the subject of Diderot’s atheism; in particular he shows with the utmost clarity how this deterministic atheism raised more problems than it solved. If Diderot was tempted by a hedonist ethic which removes all moral barriers and encourages man to make himself happy by satisfying all his supposedly “natural” instincts, he never abandoned the stoical tradition which advocates discipline and self-mastery. In the most elaborate account he has left us of his thinking on biological subjects, he anticipates the ideas of modern neurology about the unifying control exercised over the “peripheral” functions by the cerebral “centers.” However indulgent his moral thinking may be to the satisfaction of the senses, he always endeavors to go beyond the kind of pleasure which is limited to isolated impulses. Man, even if he is matter through and through, can and should exert his will, controlling his sensibility (thought of as peripheral and located in the diaphragm) and performing deeds of out-going generosity which will win him admiration and gratitude from generations yet unborn.

Self-control and detachment are the qualities which the Paradox of the Actor (1773) ascribes to the great actor, and which Diderot elsewhere attributes to “great men” in general. Resistance to despotism, which Diderot preached more and more fervently in the final years of his life, presupposes a rebellious individual capable of preferring death to slavery. Political freedom is thus made dependent on a power of self-determination which can only spring from the individual will. So Diderot’s determinism leads not to fatalism but to voluntarism, a voluntarism conscious of the conditions which limit the exercise of the will. Willed action may depend on the bodily make-up of the individual and the chain of cause and effect in the physical world, but this does not prevent man from being a creature who can be modified and can modify himself. Diderot particularly likes to cast himself in the role of the master-mind who manipulates others for their own good and enlightens them for their greater happiness. The concluding pages of Arthur M. Wilson’s book show very well how for Diderot the hope for posthumous fame in this world replaces the promised immortality which theology had located in the next.

In this way Diderot maintains a belief in the autonomy of the individual. He preserves a constant balance between the forces that work for the unity of the whole and the centrifugal tendency of the parts, the molecular elements, to live their own separate lives. This results in a vitalist mythology in which the synthesizing efforts of the active faculties are pitted against the happy passivity of dissolution into elementary living particles. Diderot’s way of choosing active self-determination while still recognizing the pleasure that comes from spontaneity is not without its resemblance to Freudian metapsychology and could be considered its equal as a poetic-scientific account of reality. Diderot favors the victory of the whole over the separatism of the parts. But ultimately this victory cannot be a complete one; some sort of compromise is inevitable. We may desire the unity of the individual, but we must accept that death, sleep, inconsistency, and internal contradiction are inseparable from the human condition.

Diderot was preoccupied then by the opposition between continuity and discontinuity. This problem faced him equally in the field of scientific knowledge. As first envisaged by its authors, the Encyclopedia was to provide a complete exposition of the system of human knowledge. Their desire for coherence and systematic order is shown, among other things, by their use of cross references to compensate for the arbitrary discontinuity of the alphabet. But Diderot himself was the first to admit that these cross references were less successful than had been hoped in making the Encyclopedia a systematic whole. Each separate article is an entity in itself, a mini-treatise followed by another minitreatise—and so on. Instead of a vast unified map of the sciences and arts, all linked together and mutually interdependent, we are given a succession of rapid images, each one relatively independent of the rest. Dispersion has won the battle against systematic organization.

This love of Diderot’s for what is immediately and manifestly present shows itself similarly in his willingness to give expression to flashes of thought, sudden bursts of feeling, and unforeseen objections. His flow of speech is always being deflected and interrupted; unexpected questions, digressions, and breaks of continuity are the ever-recurring signs of the sudden and disruptive incursion of the living present into the pre-established order of logical thought. In his work we find a permanent tug of war between the stability which a rationalist representation of the world strives after and the instability of present time as it forces itself irresistibly upon a mind perpetually in motion.

Diderot never wanted to leave anything out. His last project was a book on the Elements of Physiology, which would have been a systematic treatise laying out the main lines of a vitalist anthropology; all that survives of this work is a mass of fragments. For Diderot never closes his ears to his own internal contradictions and unforeseen trains of thought; his reaction is to embody them in an interlocutor. When he hears in himself the presence of a new thought, he immediately transforms it into an imaginary being with whom he can exchange ideas. In him the dialectic of contradiction and the dialectic of discussion are one and the same thing.

Thus is born the dialogue, a succession of moments in the present, where the author’s thought is distributed among several voices whose very opposition gives rise to a superior harmony. Dialogue is in Diderot the manifestation of superabundant presence which needs to be divided among a number of actors, each of them giving vivid expression to a feeling, a reflection, or a silence at the very moment when it emerges into existence. Even when his works are most skillfully constructed, Diderot makes them read like improvisations. It is as if he were continually letting himself be guided by the replies and gestures of an interlocutor, anticipating his questions, asking them on his behalf, and answering them in advance.

Small wonder then that physical absence favors this victory of the present in his writing. Fortunately for us the long absences from Paris of his mistress Sophie Volland forced Diderot to take up the pen, imagine her presence, and speak to her on paper. In these letters (which have just appeared in the excellent selection translated by Peter France) we find what is perhaps the quintessence of Diderot: a voice stimulated by the imagined presence of a listener, a joyful freedom kept within bounds by respect for someone else’s freedom, and a frankness which never conceals the slightest variation of mood or thought.

In these letters to Sophie Volland we only hear the voice of Diderot; the dialogue has reached us in a truncated form. The masterpiece of dialogue is Jacques the Fatalist. Here the author converses with the reader over the heads of his heroes, while they in their turn converse as they ride along, telling one another stories, and listening to the talk in inns where new dialogues are born in a virtually infinite succession. But in this work, which Arthur M. Wilson rightly considers the most modern of all Diderot’s writings, the author, as he apostrophizes his reader and declares himself free to say whatever he wants, to make his characters say whatever he wants, and to leave whatever he wants unsaid, is in fact giving us an example of that freedom to which the Romantics later gave the name of irony. He is the master of ceremonies, the indispensable voice, at once responsible and irresponsible, without which all the others would be condemned to silence. In this way the truly modern discovery of the problems of determinism combines in Diderot with another modern discovery, that of the arbitrary powers of the writer.

This Issue

March 22, 1973