Thus, in response to the radical innovations of Post-Impressionist painting, Bloomsbury gave us the notion of "significant form," which seemed to mean something at the time but was later found to be too facile a concept to explain the complexities of Cézanne or Matisse. Closer to home, the emergence of the Abstract Expressionist movement in the 1950's brought us the notion of "action painting." This was nicely designed to make it seem as if the paintings of Pollock, Rothko, de Kooning et al. were somehow akin to the Existentialist philosophy of Jean-Paul Sartre, then all the rage in intellectual circles. But "action painting," too, was an utterly bogus idea, as virtually everyone in the art world now recognizes.

More recently, in response to Andy Warhol and his Factory, we were given still another catchpenny formulation-"the end of art"-which, insofar as it means anything at all, certainly doesn't mean that artists have ceased to create works of art. What it's said to mean is that art has now, post-Warhol, become a branch of philosophy-and thus, by implication, only professional philosophers are in a position to assess its accomplishment. This notion, too, now enjoys a kind of afterlife in the seminar rooms and on the margins of media coverage of the arts.

What brings all this to mind at the moment is the exhibition called American Sublime: Epic Landscapes of Our Nation, 1820-1880 , at the Pennsylvania Academy of the Fine Arts in Philadelphia. I hasten to add that there is nothing bogus about this wonderful exhibition or its excellent catalog. In my experience, anyway, American Sublime is the best survey of its subject I have seen; indeed, it's a model of what a historical exhibition of this kind ought to be. The selection of paintings observes a consistently high aesthetic standard, and the scrupulously conceived organization is designed to illuminate not only the artistic achievements of 19th-century American landscape painting but the specific historical, social and geographical imperatives that shaped its development.

As it happens, however, American Sublime opened at the Pennsylvania Academy just as another exhibition-the Barnett Newman retrospective at the Philadelphia Museum of Art-was in its closing weeks. This coincidental overlap was bound to create some confusion in minds susceptible to bogus claims. For the late Barnett Newman (1905-1970), an abstract painter of modest accomplishment who was part of the New York School, famously claimed that his paintings also represented a version of the American Sublime. In 1948, he published an essay called "The Sublime Is Now" in the magazine Tiger's Eye , and this, together with similar writings by Newman and others, led to the notion that certain Abstract Expressionist paintings (especially the work of Mark Rothko, Clyfford Still and Newman himself) were now to be seen as belonging to the same pictorial tradition as the 19th-century paintings of Thomas Cole, Frederic Edwin Church, Albert Bierstadt et al.-the tradition of the American Sublime.

This fanciful formulation, which has absolutely no foundation in anything but facile rhetoric, proved nonetheless to be irresistible to certain art-world thinkers. The Museum of Modern Art even went so far as to mount an exhibition that was designed to prove the efficacy of the idea, but that only succeeded in establishing its absurdity. Yet there's no idea so absurd that it can't be made to serve some academic or journalistic function, and so the fiction that the paintings of Thomas Cole, say, and those of Barnett Newman were somehow joined in a common aesthetic or spiritual mission has acquired an intellectually respectable status in certain quarters of the art world.

It was hardly a surprise, then, that when I attended the press viewing of the American Sublime exhibition at the Pennsylvania Academy, almost the first question I was asked was whether I believed in this preposterous fiction. My interlocutor, who is himself a scholar in the field of the 19th-century American Sublime, was greatly relieved to hear that I did not. But I'm afraid we're doomed to see this fiction endure for another generation or so, if only in the classrooms where such fictions abound.

What does the concept of "the Sublime" mean, anyway? Andrew Wilton, in a catalog essay entitled "The Sublime in the Old World and the New," provides an excellent historical summary of this very slippery idea. For a more succinct explanation, the one given in the 11th edition of The Encyclopedia Britannica (1911) can hardly be improved upon. It reads, in part, as follows: "Sublime … in aesthetics, a term applied to the quality of transcendent greatness, whether physical, moral, intellectual or artistic. It is especially used for a greatness with which nothing can be compared and which is beyond all possibility of calculation or measurement. Psychologically, the effect of the perception of the sublime is a feeling of awe or helplessness."

Whether or not every painting in the American Sublime exhibition can be said to meet this standard of "transcendent greatness" is debatable, but it's nonetheless amazing to see so many paintings at the Academy succeed in approaching such a standard. In the 10 galleries which the Philadelphia Museum of Art has devoted to the Newman retrospective, however, the feeling of helplessness we experience in the presence of such minimal aesthetic endeavor on such an extravagant scale has nothing to do with "awe," never mind "transcendent greatness." It's a helplessness induced by sheer, unrelieved boredom-a boredom from which all the fanciful formulations of art-world rhetoric can offer no relief.

American Sublime: Epic Landscapes of Our Nation, 1820-1880 , remains on view at the Pennsylvania Academy of the Fine Arts through Aug. 25. Barnett Newman closes at the Philadelphia Museum of Art on July 7.

Realist style. With subjects ranging from water sports and baseball to affectionate scenes of domestic life and portraits that are penetrating character studies of his Philadelphia contemporaries, Eakins created a corpus of American types and pastimes that, for sheer quality, gravity and intelligence, no subsequent champion of the Realist style has been able to match.

That his career was also marked by scandal, rejection and outright character assassination only adds to the luster of a fame that has elevated Eakins to the status of a national icon. We like our artist-heroes to be fiercely independent and disruptive, and Eakins leaves little to be desired in this respect, too. He made it a habit to offend established taste, not only in painting but in the realm

of public morals as well, and this has also

endeared him to posterity. Not that offending established taste was a difficult thing to accomplish in the Philadelphia of his day, which was nothing if not staid in its standards of respectability. Eakins even dressed for the role, affecting the kind of shabby attire that polite society looked upon as impermissibly "bohemian," especially for a teacher at the remorselessly respectable Pennsylvania Academy of the Fine Arts.

Thus, while Winslow Homer was undoubtedly more beloved, and both William Merritt Chase and John Singer Sargent were far too eager to please to be cast in a heroic role, Eakins remains a singular figure in the American art of his time-and indeed, in ours as well. Which is one reason why the comprehensive retrospective that has now been organized at the Philadelphia Museum of Art- Thomas Eakins: American Realist -is bound to be a huge success. Another reason, of course, is that Eakins brought a powerful, if narrow, talent to an oeuvre that is wonderfully accessible to every level of public perception. This is pictorial Realism unburdened by the modern appetite for ambiguity, irony or obscurity. It is an art in which easily recognized sentiments and actions are clearly expressed in a manly, robust style that commands attention without challenging the boundaries of the mainstream imagination.

That the aesthetic elements in Eakins' art were deeply conservative, with affinities closer to academic tradition than to avant-garde innovation, has seldom been held against him. In fact, it is seldom even acknowledged. Owing to his reputation as a rebel and martyr at the Pennsylvania Academy, Eakins has been transformed in our literature into a kind of honorary modernist révolté , yet this is a classification that is denied in every square inch of painted canvas Eakins ever put his hand to. In every respect but one-his unremitting and incorruptible candor in registering the impact of his personal response to the American life of his time-Eakins remained a votary of academic tradition.

Yet this radical candor-which was abetted in Eakins' case by his keen interest in scientific standards of objectivity, and which was itself a spur to clarity of expression-was sufficiently rare and sufficiently affecting to set him apart from his contemporaries. Yet it was a candor expressed in an academic mode. No one understood the academic roots of Eakins' art better than his widow, Susan Eakins, who was herself a gifted painter, very much influenced by her husband's pictorial practice. Thus, when Lloyd Goodrich's pioneering study of the artist, Thomas Eakins, His Life and Work , was published in 1933, she was appalled to find that Goodrich had "disregarded Eakins' roots in the French academic tradition," as Carol Troyen writes in the catalog accompanying the current retrospective.

Susan Eakins understood that, far from being a painter "little influenced by others," as Goodrich had insisted, Eakins had been deeply influenced by his period of study

in Paris under Jean-Léon Gérôme, a retardataire Academician whose work, as Goodrich surely understood, commanded nothing but contempt in advanced art circles in the 1930's. Susan Eakins thought otherwise, of course, observing that "when a man cannot understand the greatness of Gérome I cannot think he understands Eakins." To what extent Susan Eakins came to understand that her husband had been a far greater painter than Gérome-and greater by virtue of his radical candor in rendering the look and feel of contemporary life-must remain a matter of speculation.

In the current exhibition, we are given a glimpse of the kind of academic painter Eakins might have remained absent that candor in an ambitious painting of a conventional religious subject, The Crucifixion (1880), which-in my view, anyway-is the least persuasive of all of the artist's major canvases. Compare it to the intensity of concentrated attention in The Gross Clinic (1875) or the pathos of The Concert Singer (1890-92) or the controlled passion of the rowing pictures, and you see the difference between an artist attempting to conform to convention and an artist inspired by the depth and complexity of his own response to life.

In no other Eakins exhibition that I've seen have we been given such a detailed account of the intellectual and aesthetic labor that Eakins invested in perfecting his Realist masterpieces. In addition to the expected drawings and oil sketches in the Philadelphia retrospective, we are also given a plethora of his sculptural studies and the photographs that were used in the preparation of his major paintings. Indeed, there may be a few too many photographs in the current show for most viewers, for they are not all invariably interesting, and the sculpture, too, is mainly of interest as preparatory studies for the paintings. The sculpture, certainly, can leave no one in doubt about Eakins' academic loyalties.

It is in the paintings-and in the paintings alone-that Eakins' genius was fully developed. And it is in the paintings, too, that he remains an isolated figure in the history of American art. No painter before Eakins was as audacious as he was in his account of American experience, and none that came after was in a position to resist with impunity the innovations of the modern movement. In his lifetime, Eakins paid a high price for his singularity of purpose-the singularity of a radical conservative-yet it's hard to believe that he could have achieved what he did without the social resistance he met with at almost every stage of his career. It is in this respect that he can be said to resemble one of his idols, Walt Whitman, who was the subject of one of his finest portraits.

Thomas Eakins: American Realist remains on view at the Philadelphia Museum of Art through Jan. 6, and tickets are required to see it. The show will then travel to the Musée d'Orsay in Paris from Feb. 5 to May 12. It comes to the Metropolitan Museum of Art in New York next summer, from June 18 to Sept. 15.

While certainly not lacking in splendor–if, by that term, we mean brilliant display–this is an exhibition that also often descends into the merely splendiferous. For Splendor is a major exhibition–major in the scale of its ambition, major in its scholarship and major in the sheer number and variety of the objects it contains–devoted to a subject that is, in many respects, of distinctly minor interest. As a consequence, its content, though encompassing some 442 works by 160 artists, often fails to support the scale of its artistic pretensions.

It is, after all, an exhibition built upon a historical paradox. Rome in the 18th century was a capital and a culture in irreversible decline. Its greatest artistic and intellectual glories lay in the near or distant past. Yet it was in this period of decline that Rome, largely owing to its past glories, became a magnet for some of the most interesting and ambitious talents in Europe. Privileged amateurs in the arts from Russia and England mingled with greatly gifted writers and artists from France, Germany and Scandinavia to worship at the altar of the past in the hope of replicating its achievements and preserving its spirit in future endeavors. Rome became, in effect, an academy for every sort of aspirant to greatness in the arts.

Meanwhile, however, the sun was setting on native achievement. Italian painting, which had indeed been one of Europe's greatest glories, was rapidly declining into mere competence when not falling into utter ostentation. Much of the finest talent was to be found in the decorative arts rather than in the many attempts to emulate the heroic heights of earlier Italian painting and sculpture. The most accomplished new artists tended to be foreign visitors for whom Rome, like Italy itself, was already on its way to becoming a museum.

There were exceptions, to be sure–Pompeo Batoni, among the painters, is one, and Giovanni Battista Piranesi, among the printmakers, is another–but even they were not of a stature capable of restoring Rome to its former artistic glory. And in the case of Piranesi, the only artist to be accorded a room of his own in the Splendor exhibition, his macabre architectural fantasies have, in this context, very much the look of a mordant memorial to that lost glory.

Given the problematic character of the exhibition's subject, it was a wise decision on Mr. Rishel's part to organize The Splendor of 18th-Century Rome not as an anthology of unexceptionable masterpieces but rather as a historical and cultural documentary survey of its period. Hence the division of the exhibition into sections devoted to "Rome: The City," "The Making of Modern Rome," "City of God," "City of Art," etc., an organizational plan which implicitly acknowledges that something other than strictly aesthetic judgments–an attempt to convey the ethos of a city and a period–has governed the selection of objects. It is therefore left up to the visitor to this exhibition to determine his or her own priorities.

As my own interest in monumental inkstands, gold-embroidered ecclesiastical vestments and elaborately designed inlaid tabletops is not especially keen, I shall leave the great preponderance f decorative objects and textiles in this exhibition for others to savor. As for its many paintings and sculptures and drawings, there is certainly enough of real quality to make a visit to the Splendor show worthwhile, but there is also enough fluff to leave a visitor with such interests a little irritated. Two paintings of The Immaculate Conception –one by Placido Costanzi, circa 1753, the other by Stefano Pozzi, circa 1762–are of an insipidity that is not to be borne, but such things are to be expected in an exhibition in which historical considerations are given priority over aesthetic judgments.

Giovanni Paolo Panini is a far more interesting painter, and since his pictures of the Interior of the Pantheon, Rome, the View of the Palantine, Arch of Constantine and the Colosseum, Rome, and other such subjects are themselves brilliant documentaries, it was inevitable that he would be abundantly represented in this exhibition. Moreover, it is from Panini's Imaginary Picture Gallery paintings, in which vast interior spaces are tightly packed with pictures and other art objects too numerous to count or even look at, that Mr. Rishel seems to have derived his own style of installation for the Splendor show. Yet, when you return to Panini's paintings for a second or a third look, they turn out to be interesting only as documentary or imaginary accounts of Rome.

It is principally Batoni who salvages the honor of Italian painting in this period and in this exhibition, and when you confront his grand portrait of Count Kirill Grigoriewitsch Razumovsky (1766) and his other pictures in this exhibition, you can almost forgive some of its fripperies. But it is the painters and sculptors from elsewhere who provide the greatest interest. If only for the paintings by Jacques-Louis David in this show–among them, the Academy Male, Called "Hector" (1778), from the Musée Fabre in Montpellier; Saint Roch Interceding for the Victims of the Plague (1780), from the Musée des Beaux-Arts in Marseille; and a version of The Oath of the Horatii (1786) from the Toledo (Ohio) Museum of Art, this exhibition would be worth a visit.

For many, however, the real discovery in this exhibition will be the German painter Anton Raphael Mengs, who is very strongly represented here and to whose pictures one finds oneself frequently returning. In both his portraits and his allegorical paintings he is one of the real stars of the show. It's a pity that some of the other foreign talents in the exhibition–the Swiss-born English artist Henry Fuseli, the German painter Asmus Jakob Carstens, the Danish painter Nikolai Abraham Abildgaard and the Irish painter Hugh Douglas Hamilton–could not have been more amply represented. Abildgaard's Philoctetes on Lemnos is a knockout painting. I would have happily sacrificed one or two of the Panini views for more Abildgaard.

But that's one of the problems with documentary exhibitions. It's always a little of this and a little of that, until in the end one leaves with the impression of having seen something of a miscellany. Except for that last room devoted to Piranesi, whose vision renders a judgment on Rome in the 18th century much harsher than mine.

The Splendor of 18th-Century Rome remains on view at the Philadelphia Museum of Art through May 28, and will then travel to the Museum of Fine Arts in Houston (June 25-September 17).