NEW YORK -- Half a century ago, in an argument invoked incessantly since then, the critic Clement Greenberg swung a kind of flaming sword and cut art in two. Above -- detached from commonness -- was the contentless, near-Godly art of Picasso, Braque, Miro and their avant-garde colleagues. Below was, well, just about everything else -- "popular commercial art," all images in magazines, especially their ads, and "comics, Tin Pan Alley music, tap dancing, Hollywood movies, etc., etc." -- which Greenberg labeled "kitsch."

"Kitsch," he wrote, "is mechanical and operates by formulas. Kitsch is vicarious experience and faked sensations. Kitsch changes according to style, but always remains the same. Kitsch is the epitome of all that is spurious in the life of our times."

Greenberg, one feels confident, will not be much delighted by "High & Low: Modern Art and Popular Culture," the enormous exhibition that goes on view today at the Museum of Modern Art. Here Picasso plays with schoolboy puns, here Krazy Kat cavorts with snippets from catalogues and oils by Miro. This show, and its vast catalogue, takes the sort of art Greenberg most despised -- the art of newspapers and magazines, of graffiti scrawled on walls, of shop windows and comic books -- and gives it pride of place with the Braques and the Picassos that he admired most.

"High and Low" was organized by two very bright young scholars, Kirk Varnedoe, the new director of MoMA's department of painting and sculpture, and his former student Adam Gopnik, who writes for the New Yorker. Long before its opening, their genre-mixing show had set New York alight with anticipatory bitchiness. Seldom has an unseen show been so bitterly attacked.

The critics of the right -- let's call them the elitists -- are certain that the Modern has sold out to the crowd. "The museum," writes Barbara Rose in the Journal of Art, has "abdicated its role as cultural referee by putting what used to be out in the streets inside its sanctuary." Her complaint is drenched in scorn. "This shuffling of the unique icons of Modernism with the multiple reproductions of commercial culture gives those who cherish such 'collectibles' as old comics, matchbook covers, vintage movie posters and celebrity memorabilia a welcome sense of being in with the in crowd... . No longer is it necessary to be torn between the either/or opposition of high vs. low: now we may simultaneously savor the moral uplift of the former and the guilty pleasures of the latter... . By aligning ourselves with the currently 'hip' premise of the equal validity of all forms of cultural expression from Mozart to MTV, we claim that all of us, not just girls, just want to have fun."

Critics on the left -- who see themselves as populists -- have also sharpened their long knives. A month before the opening, word artist Barbara Kruger, writing in the New York Times, was already stabbing Varnedoe and Gopnik for "playing the old high-low card." "What's High, What's Low, and Who Cares" was the headline of her screed. "Let's see," she wrote. "Art is obviously art, right? ... {But} does a spot in a museum's chorus line of wall trophies guarantee an experience of art that an urgently pleasurable piece of pop music can't aspire to? What about the witty eloquence of urban Afro-American dance, the brilliant nuances of Tracey Ullman's and Sandra Bernhard's comedic characterizations, and Queen Latifah, Salt-n-Pepa and other much-awaited female rappers telling it like it really is?"

But now that "High and Low" is actually on view, both complaints ring hollow. The Modern has in no way abandoned its traditional devotion to the "high," familiar icons -- by Picasso and Brancusi, Delaunay and Duchamp, Miro, Johns and Rauschenberg, Lichtenstein and Warhol -- it has displayed for years. Far from it. Nor has it condemned popular, commercial art as unworthy or inferior. Varnedoe and Gopnik, unlike many of their colleagues in other art museums, here happily acknowledge that such fine comedic draftsmen as R. Crumb and Saul Steinberg, Winsor McCay and George Herriman are masters of a sort, and it is about time.

The Modern's exhibition is not a show shaped like a ladder, with Picasso on the top rung and Mr. Natural on the bottom. Nor is it a level plain on which the graffiti scrawled in alleys and the Readymades of Duchamp assume equal value. "High and Low," instead, is a show shaped like a wheel, in which styles fructify each other in a constant cyclic interchange. Here the curators convince us. They write: "From small symbolic motifs, like sans-serif letters or Benday dots, to strategies such as gigantism or jumbo styling, to broad models like the billboard's use of huge, flat planes of color, no style remains fixed in its original place, but passes along the wheel from low to high and back again ... and back again." Their show goes round and round.

Take, as one example, Varnedoe's impressive discussion of graffiti. No imagery is older -- the "meaningless" meanders drawn on walls of Ice Age caves are graffiti of a sort. And no sort of art is "lower" -- just think of the markings scratched on bathroom walls. Yet Varnedoe detects in such atavistic "writing" an energy, an attitude, that has touched in unexpected ways much of modern life, and much of modern art. "It has been praised and damned," he writes, "as the telling upsurge of the 'primitive' into the present, and has been embraced as the last authentic domain of a 'natural' expressive art. In an age of processed information, this guerrilla channel gives us raw news from society's margins; the writings on public walls appear to manifest libido without limits; an urge to defile, triumphant over respect for property or fear of law; and the shrieking, antisocial assertion of 'me' over civic constraint."

It is vandalism, surely, yet it has been transmuted by many modern artists into poetry as well. To wander through the catalogue is to feel the wheel spinning -- from anonymity to signature, from defacement to adornment, from the coarse into the sweet. The evidence here mustered includes learned tomes on criminality, tattooing and Pompeii -- and works produced in various moods by artists as diverse as Giacomo Balla, James Ensor, Jackson Pollock, Miro, Aaron Siskind and Brassai, NOC (who spray-painted subway cars), Rauschenberg and Keith Haring.

Graffiti sometimes keeps its aura of subversion -- the gender-teasing mustache that Marcel Duchamp drew on a postcard reproduction of the Mona Lisa seems subversion pure and simple, and yet, on second thought, it's not so simple after all. Sometimes it suggests the violent rage of the outsider, a rage turned into beauty by such artists as Jean Dubuffet. And sometimes, unexpectedly, it eerily rotates from defiance and defilement into saccharine self-indulgence. It seems to do just that in the phonily naive, vastly overrated paintings of Cy Twombly, the chief weakling in this show.

Any net that's wide enough to cover Twombly and Duchamp, Pollock and Brassai is certain to have holes. But this net, like the others woven by the authors, is there to haul in thought.

Gopnik's discussion of caricature is equally impressive: "Modern art," he writes, "is full of funny faces. Women with both eyes on the same side of their nose; men with ears where their mouths should be; ordinary families with the eyes of desert rodents and the skulls of apes -- a mixed up face is the heraldic emblem of modern art in the same way that the beautiful nude is the emblem of antiquity, or the receding-perspective checkerboard the emblem of the Renaissance." Once one starts to think of caricature as a kind of undertone that runs through modern art, another net is tossed over objects as diverse as Munch's screaming figure, Brancusi's kissing blocks and "The Rape" of Magritte.

Caricature once was meant to set you smiling. But the portraits of Dubuffet do nothing of the sort. They "seem to sum up in a single scowl not just an individual but a whole city and climate of opinion -- the moral rot and catacomb chic of Parisian intellectual life after the German occupation." The last self-portrait of Picasso is just as disturbing. It is a caricature, surely, yet no one with a heart can look at it and grin.

Some may see Picasso as the highest sort of artist, but he's a caricaturist too, and a fan of half-dumb puns, and a lover of the comics, who pounded much dismissed as low into the amalgam of his art.

The wheel keeps on turning. Often its spokes sparkle. Varnedoe and Gopnik call attention, for instance, to the strangeness that adheres to common objects isolated eerily in shop window displays. The Readymades of Duchamp, and the disturbing giant objects painted by Magritte, and those made by Claes Oldenburg, and Andy Warhol's soup cans, suddenly begin to share an odd, commercial intensity seldom sensed before.

Perhaps the most impressive passage in this show is that which helps us see how Braque and Picasso, Miro and Duchamp, Joseph Cornell and Robert Rauschenberg -- each in his own way -- magically transmuted the dullest little images found in catalogues and newspapers into major works of art.

"In 1933," writes Varnedoe, "in order to provoke his imagination with points of sharp resistance -- as a grain of sand irritates an oyster into making a pearl -- Miro cut out from ads and sale catalogues a roster of images of silverware, household objects, combs, machines and the like, and arranged them in an unpredictable variety of ways on eighteen large sheets of paper." Some are on display. "From these, by dint of scrutiny with a willfully hallucinating eye, he conjured the compositions of eighteen paintings... . {U}nder the heat of his gaze the colanders and combs mutated into fabulous creatures by fast-forward evolution ... and eventually the figural elements in the paintings -- while still carrying in uncanny ways the physiology of combs and forks and so on -- shed the carapace of their origin, to become soft bodied creatures populating nocturnal, aqueous environments altogether different from the clinically white isolation of their paste-up pages... . Miro saw that the dreams of retail produce monsters... ."

Joseph Cornell's boxes also employ snippings, but they use these scraps of paper to evoke a kind of deep, nostalgic longing. "From hotel ads and chocolate labels, in boxes that were part coffin and part cradle," observes Varnedoe, Cornell "made a Europe of the mind."

What Varnedoe and Gopnik have managed to come up with, after years of thought and labor, has three praiseworthy virtues -- and one familiar flaw.

The chief virtue of their enterprise is without doubt its catalogue. That 460-page volume -- with its superb illustrations, enormous erudition -- seems to me to be among the most rewarding books on reading modern art to appear in many years. Both men write extremely well, both steer shy of jargon. They're exceptionally good teachers too. Their pages make you think.

Creditable too is the range of their attack. Big-theme shows are rare because intellectually demanding. Single-artist shows, of which we've seen too many, are in comparison a snap.

Also to be praised is their adamant refusal to lean on easy, airy theories. It's easy to slam Hollywood or tap dancing or popular entertainment, as Greenberg did so confidently, but only if one speaks in generalities. For tap dancing read Fred Astaire, for popular entertainment Thelonious Monk or Charlie Parker, and the claim that "kitsch" cannot be art begins to seem ridiculous.

Varnedoe and Gopnik avoid mushy claims. In fact they marshal facts -- facts that teach and glint. Here, as one example, is Gopnik on Bud Fisher, the San Francisco draftsman who invented Mutt and Jeff:

"He came east, drew his comic strip, became enormously wealthy -- a ladies', or anyway chorus girls' man -- and by 1914 was hungry for a larger adventure. He ended up in Mexico beside his friend John Wheeler fighting alongside Pancho Villa... . ('R. Mutt,' partly after Fisher's creation, was of course the name that Marcel Duchamp signed on his 'Fountain' in 1917. So a single orbit of the imagination gives us Duchamp, Pancho Villa and Mutt and Jeff, all together -- a modern historical romance waiting to be written.)"

The freshness of their catalogue is constructed of such stories and peculiar facts.

But that freshness somehow vanishes as one wanders through their show.

The show feels oddly stale. It opens with cubist collages -- as if it were extending the Modern's recent Picasso and Braque exhibit. It's got much more work by Warhol than one needs to see -- a Warhol retrospective closed there a few months ago. The catalogue surprises. The accompanying exhibit does so only rarely. It's insistently canonical, disappointingly familiar. A dozen Picassos, a dozen Braques, a like number of Oldenburgs, and soon the eye grows numb. Time and time again, the exhibit at the Modern, despite its R. Crumbs and its Dubuffets, offers us the same old stuff -- the same old fur-lined teacup, the same old painted ale cans -- that we have seen, and seen again, too many times before.

Varnedoe will tell you he was looking for "the payoff." "Either this idea spoke directly to the best of art, explaining something fundamental," he contends, "or it wasn't worth exploring." But unless you've read the catalogue you may explore this show uncomfortably suspecting that its core intention is to reinvigorate with low art the familiar high art MoMA line.

The exhibition's ending, despite Elizabeth Murray's presence, is thoroughly distressing. If the "ur-kitsch" of Jeff Koons (the term is Adam Gopnik's) and Jenny Holzer's words (which blend dull schoolgirl morbidities with fortune cookie platitudes) are the best art of the recent past, have pity on us all.

"High and Low," sponsored by AT&T, will travel to the Art Institute of Chicago and to the Museum of Contemporary Art, Los Angeles, after closing at the Modern on Jan. 15.