For all the 20th-century emphasis on iconoclasm and experiment in the arts, the motto of the period may well turn out to be "there's nowhere to go but back."

It's true, of course, that from the beginning creative artists have rifled the works of their predecessors for ideas, themes and methods. The history of the arts, in fact, could be rewritten as a treatise on the use of quotation. But never before has past art played so formidable a role in shaping the art of the present.

In the realm of popular culture, "Star Wars" comes most easily to mind as an illustration -- a film that virtually equates the future with the past, and not just its Hollywood past, but the whole notion of an era when you could tell heroes from villains and stories had beginnings, middles and ends.

A glance at Variety's current list of top-grossing movies, however, studded with such features as "Julia," "The World's Greatest Lover," "1900," "The Man who Loved Women," "Roseland," "The Turning Point" and "High Anxiety" shows how unexceptional "Star Wars" is in its retrospective tendencies.

Many reasons could be found for this contemporary doting on the past. To begin with, the past, both immediate and distant, is so much more accessible now than in earlier times. Not only do we strive more diligently to collect and guard the historical facts, we also have -- in this century of the phonograph, the tape recorder, motion pictures, videotape and computerized memory banks -- far more effective means of doing so.

Nostalgic cravings are often rooted in a desire to retreat from the present, and this too may be a factor in our persistent obsession. In the arts, moreover, pressure has come from a prevalent feeling that our inherited esthetic vocabularies may have reached a state of exhaustion -- a feeling, not necessarily that everything that needs saying has been said, but that we have run out of ways of saying things in a fresh and compelling manner. Hence, we fall back on poaching on our forebears.

"High anxiety" and "Star Wars" exemplify two different modes of the quotational impulse, the one employing deliberate parody of a "classic" filmmaker (Hitchcock), the other roaming freely among the stereotypes of a dozen traditional movie genres.

Recycling artistic legacies is an antique habit. Music history is especially instructive in this respect. The music of the Middle Ages, for instance, grew by a process of accretion, the work of one generation serving as actual scaffolding for the next. The favorite activity of "tropping" was a process of inserting new phrases into old chants, or adding new melody at the end. The "cantus firmus" of the medieval composer was an already existing chant or popular song that then became the foundation of a polyphonic mass or motet. The so-called "parody mass" went even further, borrowing whole hunks of earlier counterpoint.

The whole phenomenon of opera got started as an attempt to resurrect what was thought of as the form of ancient Greek drama. Bach's celebrated harmonizations of Lutheran chorales, the pillars of so many of his choral and organ pieces, were the spoils of a revered tradition. The procedure continues unabated through the centuries --Irae" melody as a symbol of mortality from Berlioz to Rachmaninoff.

But in music, as in the other arts, the expropriation of past models becomes almost a 20th-century fetish. Nearly all of Stravinsky's output can be seen as a rechanneling of earlier styles, from Gesualdo to Webern, and this aside from his specific homage to Tchaikovsky, Pergolesi, Bach and other composers in works designed for the purpose.

Charles Ives was so fond of direct quotation, from American vernacular songs and hymns, that such occurrences became a hallmark of his music. More recently, a slew of composers has been picking up his trail (e.g., Lukas Foss in "Baroque Variations").In some of his compositions, George Rochberg has moved through one historical style after another, all enclosed within his own contemporary syntax.

Thomas Mann's "Doctor Faustus" and Joyce's "Ulysses" are poles of a modern literary tradition that leads circuitously to such innovative strategies as those of Doctorow's "Ragtime," in which the fictive and actual past are blended into a single, richly allusive texture.

Architecture, the most public of arts, has never severed itself entirely from archetypal models, so that the main building of M.L.T. is a transfigured Parthenon, St. Peter's dome is replicated in three out of four legislatures, and newer buildings mirror everything from ziggurats to palazzos.

Modern painting is a veritable palimpset of historical cross-references, sometimes impudent, as in Duchamps' mona Lisa with the moustache, and sometimes affectionately brash, as in Lichtenstein's glosses on comic strips.

Because dance traditions have been transmitted across the generations mostly through fragile personal memories, choreographers have been paradoxically more bound to and more independent of their esthetic ancestry than other creative artists.

In the present century, however, dance has exhibited just as strong leanings toward remodeling as the other media. Fokine's renowned "Les Sylphides," at the very start of the era, is a conspicuous instance of the conscious "modernization" of a historic ideal. In their separate ways, Balanchine's "Vienna Waltzes," Tharp's "Push Comes to Shove" and Ailey's "Revelations" each renovates particulars of its authors' choreographic heritage. Merce Cunningham's recent "Events" has actually been strings of quotations from his own creative dossier.

within the young art of the movies, "Singin' in the Rain," which brilliantly satirized the history of the realm from one-reelers to talkies, is as good an illustration as any of the penchant for self-referential material over the past three decades.

One also recalls that the French "new wave" was motivated in part by a newfound respect for "lowgrade" American gangster films, as manifest in such pictures as Godard's "Breathless" and Truffaut's "Shoot the Piano Player." Along somewhat different lines but still pertinent is the kind of historicism one finds cropping up in Kubrick's "Barry Lyndon" or Fassbinder's "Effi Briest," which attempt to reproduce not just period settings but period esthetics.

As for television, it's clear from offerings ranging from "Little House on the Prairie" to "I, Claudius" that heed is being paid to this yen for the archaic. What might be forgotten, though, is that the medium itself, in one respect the epitome of up-to-the-minute immediacy, is also an ever-expanding electronic museum, forever "quoting" from radio, the theater, the movies, and constantly replaying and refurbishing its own past.

Indeed, there is a sense in which the little glowing screen puts quotation marks around life itself, enframing a fabricated reality that becomes an instantaneous, automatic commentary. With the advent of the Betamax and its kindred machines, the process can be carried further toward ultimate encapsulization -- you can tape a television image of a filmed record of a live drama based on a book, say, and then play it back from today till doomsday.

In the wake of the '60s upstart radicalism, the conservative '70s have been steadily reinforcing the widespread trend toward retrospection. The irony is that in some future decade, the cultural residue of the '70s will become grist for the artistic mill, and thus vouchsafe to posterity a backreaching vision that could only be called nostalgia squared.