Ideal criticism, Baudelaire wrote, is “partiale, passionnée, politique”—“subjective, impassioned, committed.” Add “conversational, opinionated, informal” and you have a description of the writings of the man who could be called the first modern art critic, the great eighteenth-century philosophe Denis Diderot. Diderot’s detailed reports on the “Salons”—vast exhibitions, held at the Louvre, of works by members of the Royal Academy of Painting and Sculpture— hold their own with the liveliest, most personal documents of the period, and, at the same time, point ahead to such nineteenth-century efforts as the art writing of Baudelaire or Stendhal. Composed equally of meticulous observation, unabashed value judgments, uninhibited digressions, and outrageous asides, Diderot’s “Salons” vividly bring to life the taste, aesthetic arguments, and obsessions of an entire era. They are also models of vigorous, flexible language, a French that is elegantly refined and wholly natural, cultivated and informal, either all at the same time or with one mode dominating, according to what is suitable to the subject. Even a cursory reading of these trenchant chronicles makes it easy to understand why their author was celebrated for his brilliant conversation. Great stuff, in other words.

In Diderot’s lifetime, these remarkable essays remained unknown to the public, since they were written for a private manuscript newsletter, Correspondance littéraire, edited in Paris by an expatriate German and circulated through diplomatic channels; its subscribers, never more than fifteen at a time, included the rulers of Russia, Poland, and Sweden, the Grand Duke of Tuscany, and a cross-section of German nobility. Eventually, Diderot’s commentaries were published, but only in French. English-speaking audiences either had to read them in the original or rely on translated fragments embedded in broader discussions. (Michael Fried’s Absorption and Theatricality: Painting and Beholder in the Age of Diderot, for example, includes substantial chunks of the “Salons” in support of its thesis.) This fall, an English translation of Diderot’s critical writings on art appeared at last. Yet even this two-volume edition is not complete, but is limited to his long, discursive discussions of the Salons of 1765 and 1767, which are generally regarded as the highpoints of his career as a critic. Volume 1 also includes “Notes on Painting,” a text on aesthetics written in 1766 as an appendix to “The Salon of 1765.” It has taken almost two hundred years—the first of Diderot’s “Salons” was published in France in 1798— but this new English edition, ably and intelligently translated and annotated by John Goodman, with a thoughtful introduction by Thomas Crow, was worth waiting for.

Goodman’s English faithfully captures both the rapid, conversational style of Diderot’s French and its lapidary elegance. Goodman has tilted his translation toward the vernacular by using contractions throughout, a device that obviously does not altogether mirror Diderot’s constructions; it does, however, capture the informality of the original, the sense that we are reading private notes made in front of the works of art. Crow provides an informa- tive, eminently readable context, leading us through the complex histories of the Academy system and the Salons, reminding us of the gulf that separated artists who were Academicians, in terms of reputation and preferment, from those who were not.

Just as eighteenth-century France saw the development of such great complexes for the production of state-owned monopolies as a Royal Saltworks, a Royal Foundry, and a Royal Glassworks, the establishment of the Salon in 1737 created a kind of state monopoly on the exhibition of art, or at least of the art produced by members of the Royal Academy. Only members of the Academy, who had followed the prescribed course of study and had been deemed worthy by their senior colleagues, could receive royal commissions or establish schools. (Non-Academicians could function as paint- ers and sculptors, but under the guidelines of the medieval guild.) Only Academicians could exhibit in the immense annual or biannual summer exhibitions that came to fill a great square salon of the Louvre— which gave the show and the pamphlets written about it their name. It’s difficult for anyone used to today’s constant barrage of exhibits, small and large, uptown and downtown, to conceive of the impact and importance of this great collective event. Perhaps the Whitney Biennial offers an analogy, in terms of notoriety if not of effect, although it has none of the inclusiveness of the Salons, where many hundreds of works were hung edge to edge, with large-scale, heroic figure paintings with classical or religious motifs slung high, and smaller, more intimate works hung at eye level. Like the Whitney’s recurring extravaganzas, the Salons were regarded as public entertainments, and they attracted an extraordinarily diverse group of visitors throughout the six weeks of the exhibition; members of the nobility and the middle classes crowded together with artisans and foreign visitors to view the spectacle, one of the very few times the classes mingled in the days of the Ancien régime.

Visitors did not contemplate the works of art with hushed reverence but apparently indulged in spirited discussions, expressions of opinion, and debate, among artists and the lay public alike; and printed commentary—the origins of modern-day art criticism—soon appeared that not only described what was to be seen but also echoed these exchanges. Yet by the 1750s, this had become limited almost exclusively to what Crow calls “tame, affirmative reviews,” regulated by the authorities on the principle that negative comments would prejudice readers who hadn’t seen the show against the artists who received poor reviews, thereby damaging their reputations. There was often little difference between the catalogue of the exhibition, with its explanation of the subject of each work, and the commentaries published about the show.

Diderot’s essays, quite to the contrary, are not only meticulously descriptive—a necessity, given the technology of illustrations of the period—but argumentative, demanding, highly critical. Why, is obvious. His audience, back in their palaces in Sweden and Russia, relied on him to re-create for them the experience of visiting the Salon in all its aspects. The carefully crafted immediacy of Diderot’s “Salons,” which read as though they were written on the spot, deliberately echoes the aesthetic free-for-alls held in front of the pictures. (Diderot’s initial report on the Salon of 1759, written at the request of the publisher of Correspondance littéraire, is quite short and probably is a record of his immediate responses; his later, greatly expanded essays preserve the rapidly noted quality of the first.) Diderot makes no effort to be polite or agreeable. “I collected,” he says at the beginning of his article on the Salon of 1765, “the verdicts of old men and the thoughts of children, the judgments of men of letters, the opinions of sophisticates, and the views of the people; and if it sometimes happens that I wound artists, very often it’s with weapons they themselves have sharpened for me.” Sometimes he is very acerbic, indeed. How did he get away with it? Since Correspondance littéraire was not published in the ordinary sense, but circulated privately, it escaped the scrutiny of the Royal censors.

Diderot’s readers relied on him not only for news of what was going on in the Parisian art world of the day, but for advice and “hot tips” about what to collect— remember that Diderot negotiated the sale of important collections of French painting to Catherine the Great of Russia, one of the newsletter’s subscribers. Writing about the Salons of 1765 and ’67, he seems full of confidence, voluble, happy to declare himself. He conscientiously takes his readers through the shows, following the presentation in the official catalogue. Each entry begins with a description, as much to jog Diderot’s own memory, perhaps, as to enlighten his readers, followed by a discussion of the work’s merits and faults; with pictures he takes seriously, these can turn into long digressions, sometimes cast in the form of real or imaginary conversations. In a celebrated passage written to “fill out” an entry on a controversial Fragonard, which Diderot failed to see because it had been removed by the time he visited, he invents a extended dialogue with the publisher of the newsletter about the depiction of classical themes, ostensibly a description of “a very strange vision which tormented me one night, after a day on which I’d spent the morning looking at the paintings and the evening reading some of Plato’s dialogues.”

Diderot pulls no punches. “Taste is deaf to all pleas,” he writes. What is taste? “A capacity, acquired through reiterated experience, to sense the true or the good, along with the circumstances rendering it beautiful, and to be promptly, vividly moved by it.” The critic’s role is to apply his taste and decide what is true, good, and beautiful, and what is not. “I must warn you, my friend,” he writes, “not to assume that all the paintings I discuss briefly are simply bad. [Many] are positively detestable, infamous.” A later entry bears out the warning: “We owe, my friend, a bit of thanks to our bad painters,” he writes of a now forgotten exhibitor, “for they spare both your copyist and my time. Please convey my gratitude to Monsieur Valade, if you ever meet him.” A further note on Diderot’s method follows: “When I point out flaws in a composition, assume, if it’s bad, that it would remain bad even if its faults were corrected; and if it’s good, that it would be perfect if these faults were corrected.”

Diderot has absolutely no hesitancy about suggesting changes that would improve pictures. He does not content himself with minor cavils about drawing or rendering but provides long recipes for what the painter’s entire conception should have been from the beginning. His advice about a group of four thematically linked pastorals by Boucher, which together tell the story of the course of a love affair, is relatively mild: “This is less interesting than the preceding one,” he says of the third panel, “and it’s the artist’s fault. This should have been the spot of the rendezvous; it’s the fountain of love. The color still rings false.” He praises the details of the fourth panel, which depicts the rendezvous, but insists that “the letter should have been read here, and the rendezvous placed at the fountain of love.”

Even pictures Diderot admires whole-heartedly can elicit a spate of corrections. He writes of a Greuze, The Bad Son Punished, which he finds otherwise first rate: “I don’t think the mother’s action rings true for this moment; it seems to me that she’d have put up one of her hands over her eyes, to block out both her son and her husband’s corpse, and directed the ungrateful son’s attention to his father’s body with the other. The rest of her face could have expressed the intensity of her pain just as clearly, and her figure would have been even simpler and more sympathetic.”

Diderot praises Greuze as “the first who has set out to give art some morals, and to organize events into series that could easily be turned into novels.” Morality counts for a great deal. Diderot goes into raptures over Greuze’s The Well-Loved Mother, in the Salon of 1765, declaring this imaginatively composed image of a large and affectionate family to be “excellent both for the talent it demonstrates and for its moral content; it preaches population, and paints a sympathetic picture of the happiness and advantages deriving from domesticity.” By contrast, Boucher is repeatedly taken to task for both his subject matter and his execution. Diderot writes of Boucher: “there’s such a confusion of objects piled one on top of the other, so poorly disposed, so motley, that we’re not dealing so much with the pictures of a rational being as with the dreams of a madman … And then in his landscapes there’s a drabness of color and uniformity of tone such that, from two feet away, his canvas can be mistaken for a strip of lawn or bed of parsley cut into a rectangle.” Diderot sees these problems as expressions of flaws in Boucher’s character: “I don’t know what to say about this man. Degradation of taste, color, composition, character, expression, and drawing have kept pace with moral depravity. What can we expect this artist to throw onto canvas? What he has in his imagination. And what can be in the imagination of a man who spends his life with prostitutes of the basest kind? ” But Diderot backs up his moral objections to Boucher with a list of pictorial shortcomings, faulting his figures both for their low moral tone—“[His] Virgins? Precious little flirts. And his angels? Wanton little satyrs”—and for formal problems. Boucher, Diderot complains, seems to have stopped looking at nature, and instead works by rote, to produce predictable stock figures that lack truth and invention. Yet despite his antipathy, Diderot’s eye, his “brutal taste,” as he terms it, forces him to praise some of Boucher’s pictures, just as, despite his enthusiasm for Greuze, that same “brutal taste” obliges him to declare that along with “many excellent” works by the artist in the Salon of 1765 are “some mediocre, some good.”

Throughout, Diderot makes it clear that what he values most is a seamless fusion of imaginative conception and appropriate staging; technique is important and necessary, but less significant than conception. When he celebrates the now-forgotten Francesco-Giuseppe Casanova (a pupil of Guardi’s and the brother of the Casanova) Diderot calls him “a great painter. He has imagination, he has verve; his brain gives forth horses that whinny, caper, bite, kick, and fight, men who slaughter one another in a hundred different ways, smashed skulls, pierced chests, screams, threats, fire, smoke, blood, the dead, the dying, all the confusion, all the horror of a free-for-all. He also knows how to arrange the most tranquil of compositions.” And, Diderot adds, almost as an afterthought, “several of the most important technical skills are his to command,” without itemizing them.

Greuze is praised for his ability to tell stories with a wealth of truthfully observed details, stories that send the viewer into reveries about what has happened in the time before the scene depicted and what will happen as a result. Greuze’s Young Girl Crying Over Her Dead Bird, which Diderot calls “a delicious painting, the most attractive and perhaps the most interesting in the Salon,” provokes a long, one-sided conversation with the weeping subject of the picture, about the cause of her grief. Nothing to do with the death of a bird, Diderot concludes; everything to do with seduction and abandonment. He reminds us that Greuze had already painted a similar subject, using the metaphor of a broken mirror. (There’s also one with a basket of broken eggs, a spilled pitcher, and more; images of lost innocence obviously appealed to eighteenth-century French collectors.)

Diderot’s fascination with subtleties of visual narrative is not surprising in a sophisticated viewer of the period. What is surprising are the occasional flashes of “formalist” criticism, notes about painterly concerns that remind us of his friendships with artists and his participation in their conversations. The “Notes on Painting” that follow “The Salon of 1765” bear witness to Diderot’s familiarity with studio talk, as do his entries on his friend Chardin’s pictures. It’s very much to Diderot’s credit that Chardin was one of his favorite painters—and for what present-day observers might call the “right” reasons. “The man is the finest colorist in the Salon and perhaps in all of painting,” Diderot says, marveling at the orchestration of hues in a picture unpromisingly titled Third Painting of Refreshments Intended for a Place Between the Two Others: “The biscuits are yellow, the jar is green, the handkerchief white, the wine red, and the juxtaposition of this yellow, this green, this white, this red refreshes the eye with a harmony that couldn’t be bettered; and don’t think this harmony is the result of a weak, bland, over-finished style; not at all, the handling throughout is of the greatest vigor.” (Diderot tells the collectors among his subscribers: “If it’s true that no connoisseur can dispense with owning at least one Chardin, this is the one to go after.”)

The discussion of A Basket of Plums is even more remarkable: “Chardin’s handling is unusual. It resembles the summary style [manière heurtée] in the way one can’t make things out from close up, while as one moves away the object coalesces and finally resembles nature; and sometimes it affords as much pleasure from close up as from a distance. (Italics mine.) This man is as superior to Greuze as the sky is high, but in this respect alone. He has no style; no, I’m mistaken, he does have one that’s his alone; but because it’s his own style, it should ring false in certain circumstances, and it never does.”

Most of the artists Diderot writes about interest modern readers less than Chardin or even Boucher, Fragonard, and Greuze. The majority of the Academicians of the mid-eighteenth century are now forgotten, obscure, or of interest only to specialists. Diderot admired many of them, but found even more wanting. In “Notes on Painting,” he takes the system that produced these artists to task. Nature, Diderot maintains, “does nothing that is not correct” (think about Rousseau and the idealistic values of the Enlightenment when you read this), but the Academy destroys the aspiring artist’s ability to learn from nature. During the “seven cruel and difficult years” spent drawing from the model at the Academy, “one’s draftsmanship becomes mannered. All these studied, artificial, carefully arranged, academic poses, all these movements coldly and ineptly imitated by some poor devil, and always the same poor devil, who’s paid to appear, undress, and let himself be manipulated by a professor three times a week, what do they have in common with postures and movements in nature?”

But reproducing nature, however faithfully, is not enough. The artist must spark the viewer’s imagination, just as experiencing nature directly does. Confronted by a high mountain covered with an ancient forest and a rushing stream that descends to a canal and then to a mill set among tidy farm buildings, Diderot tells us, “I look into myself and I dream.” The dream is a complex chain of reasoning and association that ends in a sort of frisson. The philosopher, he says, “reflects, seeing … in the rushing water at one moment, the source of life, at another the ravage of the countryside; then thinking on its fusion with larger streams and rivers, on commerce, the inhabitants of the universe connected to one another … and his volatile soul will pass rapidly from a tender, voluptuous feeling of pleasure to a sensation of terror, if his imagination proceeds to summon up the waves of the ocean.”

Diderot expects no less stimulation from a painting that he regards as good. But the viewer has obligations as well: “pleasure increases proportionately with imagination, sensitivity, and knowledge. Nature and the art that copies it have nothing to say to a man who’s stupid or cold, and very little to a man who’s ignorant.”

Diderot writes primarily about paintings, since painting dominated the Salons, but there are short sections devoted to sculpture in his newsletters. Much of the sculpture exhibited he finds problematic. “Sculptors are more attached to the antique than painters,” he says, perhaps because no painting has survived from antiquity, while many statues have. He admits that he believes it is more difficult to judge sculpture than painting, although he immediately adds that this doesn’t mean that it is more difficult to sculpt than to paint. “Paintings remind me a hundred times over of what I see, of what I’ve seen; this is not true of sculpture,” Diderot says. “I’d take the chance of buying a painting on the basis of my own taste, my own judgment; if it were a statue, I’d ask an artist’s advice.”

He suggests that this lack of certainty ought to make him less ready to offer an opinion about sculpture, but it doesn’t. It shouldn’t, because his perceptions turn out to be remarkably acute. In one of those offhand passages, embedded in a long digression, that make the “Salons” such a delight, Diderot ponders the difference between painting and sculpture: “There’s the canvas, it’s flat, it’s on this surface that one must create. The image must spring forth, advance, take on relief so that I can move around it; if not I myself, then my eye; it must take on life. But if it’s modelled, it must live through its modelling, without resorting to the life-bestowing resources of the palette.”

Diderot’s reports on the Salons of 1765 and 1767 and his “Notes on Painting” are the most ambitious and boldest of his art writings. They show him at his peak. Earlier, he seems to be finding his way, testing his abilities, while later on, he seems gradually to lose interest in the enterprise, although there are fascinating nuggets to be extracted from all the “Salons.” The report about the exhibition of 1781, for example, is absorb- ing because it marks the beginning of the ascendancy of a new generation of Neo-Classicists not much to Diderot’s taste. The Salon of 1781 was the subject of the philosophe’s last newsletter. I don’t think I’d have renewed my subscription to Correspondance littéraire after that.