REPETITION--Need I repeat?--repetition is in again. Repetition, that is, as a fundamental structural principle for the arts, is once more in favor, at least with those segments of the creative community that seem closest to the frontier of today's esthetics.

Hold on, you may well object--was repetition ever out? Not really, of course, and never totally. Artistic expression would be almost inconceivable without it. Repetition plays such a primary role in the generation and shaping of artistic forms in every medium that it is virtually indispensable as a basic resource.

The trends of an era, however, are mostly a matter of emphasis, and so it is with the redundancy of so much contemporary art. In the wake of a period in which repetition was deliberately shunned at all possible cost, we have entered one in which repetition is cultivated almost obsessively, and in some cases, for its own sake. The phenomenon can be observed in the work of such composers as Philip Glass, Steve Reich, Terry Riley, Jon Gibson and David del Tredici; in the music of such dancers-turned-composers as Meredith Monk and Laura Dean; in the dances of such choreographers as Monk, Dean, Lucinda Childs, Trisha Brown, Kei Takei, Molissa Fenley, Charles Moulton and Jan Van Dyke; in the theater pieces of Robert Wilson and Ping Chong; in the multimedia visions of performance artists like Laurie Anderson; in the films of "structuralists" like Michael Snow; and in such commercial music genres as punk rock, disco, New Wave and jazz, from sources ranging from Keith Jarrett to Rhys Chatham and Devo.

In viewing "Dance," for instance--the three-way collaboration among choreographer Lucinda Childs, filmmaker Sol LeWitt and composer Philip Glass, seen in Washington as a highlight of last year's Ninth Street Crossings festival--the senses seem awash in an ocean of rebounding pulsations that echo, mirror and reinforce one another on a variety of levels simultaneously. One sees the dancers scudding over the stage floor in crisscross patterns, which ceaselessly permute a small number of basic steps. At the same time, through a transparent scrim fronting the stage, one sees their filmed "ghosts," replicating their movements on an enlarged scale, or from a tilted angle, or in exact likeness but at a different level. And all the while, one's ears are hypnotically attuned to the rolling throb of Glass' music, its insistent rhythms evoking in the aural domain the same kind of reverberant dithyramb that dominates the companion media.

The shift is most visible in, though by no means restricted to, the field of "classical" music. For an interval of roughly 2 1/2 decades, from the end of World War II to the late '60s, such music was dominated by the so-called "serial" school of composers, descending mainly from Arnold Scho enberg, originator of 12-tone music, and his pupil Anton Webern. The avoidance of repetition was axiomatic among serialists, who, as a consequence, wrote music which had no perceivable melodic themes, no harmonic direction and no rhythmic regularities--"perpetual development" was the aim, something new at each and every point, never the same as before.

The most rapidly rising and pervasive "school" in the music of the '70s and '80s--variously referred to as "minimal," "pulse," "trance" or "pattern" music--presents a complete contrast to the serial situation. Repetition--of melodic cells, of harmonic clusters or drones, of rhythmic ostinatos--is constant and extended, the unifying trait, in fact, of a group of otherwise quite diverse composers. There's change as well as repetition in this music, but it occurs not "developmentally," by alteration of or departure from the starting material, but by adding to or transforming what's already there--something is always the same at each and every point. The outcome is music that, whatever other qualities it may or may not possess, once more exhibits recurrent melody, intelligible harmonic progression and, above all, a steady and conspicuous rhythmic pulse.

AFTER THE LONG, dry, atonal, athematic and unmetrical night of serialism, it seems, we are back in the ordered and even tuneful universe of pulse music. But there are some odd things about the transformation. Serial music, which troubled listeners with its cerebral complexities, was itself based--abstractly, and on paper, at least--on incessant repetition, repetition of the "tone-row" or other basic series that undergirded the composition. The difference was that this repetition was inaudible, disguised as it purposefully was to achieve a surface of perpetual variation. Serialism, too, had another effect: Because the music was no longer (as in the "tonal" music of earlier eras) driven along by a tendency to resolve dissonance, it seemed static, immobile. Sound succeeded sound, but with no sense of movement or advance. Now, pulse music, which is grounded on repetition that's immediately apparent to the ear, has restored the sense of movement, which is one reason for its frequent association with dance. But it is movement without any apparent destination--cyclical, or circular, or in-place movement that just keeps undulating along but doesn't seem to lead anywhere (again, unlike the music of the past). It is music in which not the goal, but the going, is important.

In effect, pulse music induces a kind of stasis of its own, which has spurred the objections of those to whom this manner of composition seems monotonous, boring and uneventful. A little while ago, Donal Henahan, music critic of The New York Times, wrote an article titled "The Going-Nowhere Music--And Where It Came From," in which he deplores what he calls a "drift toward passivity." "Earwash," he terms this species of new music, which he also reproaches for being too much like "children's games," or for sounding (in the case of Del Tredici, for instance) "almost primitive." The trouble with such arguments is that they attack pulse music for succeeding in its aims. Children's games or primitivity may be pejoratives to some, but they are values to be prized among many of today's artists, who, weary of the enervated intellectual acrostics of their predecessors, have looked to children and non-Western societies, among other things, for refreshment and a renewed connection with nature. For these reasons, Indian ragas, African drumming and a childlike fascination with chanting and litanies have been powerful conditioning influences in much recent creative work. So, too, has been the gravity-free, euphorically floating movement of space travel, with its implications of orbital recyclings and infinite expanse.

To appreciate the crucial role repetition plays in the fashioning of artistic form--which is, after all, only the relation of parts to one another and to the whole--it helps to reflect on the creative process from an "operational" standpoint. A composer, for example, at any given moment in the making of music, has only two choices--he can repeat (literally, or with modification) what has already been stated, or he can digress. A succession of such choices will determine the overall configuration or "gestalt" of the composition, with the repetitions marking out the main structural features. From a broad perspective, all traditional musical forms can be boiled down to such elements. In ternary form, for example--the beloved ABA of musical texts and the basis of most of the familiar genres of concert hall music, from song to symphony--there's a statement, a digression and a return (recapitulation) of the initial statement. The distinctions among such categories as strophic form, rondo form, theme-and-variations form and the various polyphonic forms (fugue, canon, chaconne and the like) reside mainly in the disposition and extent of repeated material.

In pulse music, however, as in the dance-oriented music of many non-Western cultures, repetition becomes more than an organizing principle or a scheme of recurrences--it's not just a support mechanism, it's the main atttraction.

IF SCHO ENBERG was the prime modern instigator of the denial of repetition, the true patron saint of reiteration in our time was the composer Erik Satie (1866-1925). It was Satie who wrote "Vexations," the ultimate in repetitive music--a brief series of phrases for piano, to be repeated verbatim 840 times (it was performed, in 1969, by a battery of pianists in a span of 18 hours at the University of Maryland, and just last October, by a single pianist in 23 hours, at Purchase, N.Y.). Satie was not only the first "conceptual" composer, and the first to countenance boredom and monotony as legitimate artistic values, but was also, not accidentally, much attracted to children's pastimes and religious ritual. He has had a broad and enduring contemporary influence, most notably on John Cage, but his espousal of repetition as a compositional tool really lay dormant until the recent emergence of the pulse composers. There have been exceptional cases--Ravel's "Bolero," for one--but in the meantime it was left mainly to Igor Stravinsky to keep the principle active, primarily through his interest in archaic or folk-derived rhythmic and melodic formulas (as in "Le Sacre du Printemps" and "Les Noces").

The inclination toward or away from the use of repetition has sociopolitical reverberations, of a sort, especially in extreme instances. Emphasis on nonrepetition or continual novelty is associated with individualism and ultimately, anarchy, which is why Scho enberg's expressionism can be interpreted as the end product of a romantic individualism carried to the limit. By contrast, tenacious repetition implies social cohesion or collectivism, as exemplified by the many connections of pulse music and its sister arts with tribal ceremony, trance and ritual.

Pulse music also has a natural linkage of a very different kind with the age of computers, and it isn't coincidental that this music is often associated with those computer offspring, the electronic synthesizers. In modern computer science it is at least theoretically possible to reduce any data or process (eventually including, perhaps, the processes of human creativity) to a numerical expression consisting of a string of binary digits--zeros and ones. The alternation of these digits, in turn, corresponds precisely to the two choices of our hypothetical composer--to repeat or not to repeat.

Lest anyone conclude that this affinity with computers is evidence of "dehumanization," it would be well to note that there is a decidedly biomorphic impetus at work in pulse music. The restoration of pulse, of a regulated rhythmic framework, to musical esthetics has acted as a resuscitation, a revival of the heartbeat and breath blanketed by serialism. With this change, music seems also to have acquired the possibility of renewed organic life.

In any case, repetition--need I repeat?--repetition is in again, and it looks as if it is here to stay awhile.