Anyone who is going to talk seriously about postmodernism will have to acknowledge the idea that there are really two postmodernisms. The first is defined by the general characteristics of postmodern culture. The second is based entirely upon the specific elements and logic developed by each art form. The two viewpoints aren't always in agreement, and dance critics, for example, have remained cautiously in the second camp. Their agenda for dancemaking rarely considers the broader trends of cultural behavior. Instead it reads like a dissection manual of specialized operations performed upon the attitudes and techniques of earlier dance.
In ''Terpsichore in Sneakers: Post-Modern Dance'' (Boston, Houghton Mifflin Company, 292 pp., $12.95 paperback), Sally Banes writes about such first-generation postmodern dancers as Yvonne Rainer, Trisha Brown, David Gordon , and Lucinda Childs, who began to oppose modern dance's highly structured, ornately psychological style in the early 1960s. They claimed everyday movement as the property of their dance. They danced without music, arguing for the real time it takes to accomplish a movement, not the artificial measure of a metronome. They weren't against an aesthetic vision of the world. It was just that they didn't see why most of the world was being kept out of aesthetics, out of dance. To walk or crawl across a gymnasium floor or a field was just as much an aesthetic study of movement as Martha Graham's spiritualized contractions and releases of the torso or, for that matter, as a pirouette in ballet theater.
When the world was let in, the idea of the dancer's body changed. The postmoderns revolted against the most fundamental principle of classical dance, with its five academic foot positions emphasizing the clearly frontal image of the dancer as a silhouette, as a series of static poses flattened out in the illusion of two-dimensional space. They wanted to rid dance of illusions by self-consciously exposing the ways that a dance is made. This became part of the performance. And then the idea of a dance hierarchy had to go: no more prima ballerinas, no more stars. Dance movement, like the movement of the streets, would be a constant shifting of attention.
So Banes says. And it is worthwhile having this ledger of the concerns of postmodern dance. But for all of its specificity it becomes too narrow, exposing the limitations of postmodernism's second camp - its seeming unwillingness to respond directly to the changing life of culture. The problem is with the critics, not the artists. For every kind of art reflects culture, and it is only the critics' need to categorize that fosters the distinctions of art and society. Here is a particularly revealing example: Banes notes that ''Twyla Tharp . . . has been excluded from this study even though many of her early interests and methods were closely intertwined with those of the postmodernists. Tharp's aspirations have changed, or so her recent work seems to say, and rather than using popular dance forms in an avant-garde context, she works seriously in mainstream forms: ballet and movie musicals.''
It's true enough that Tharp's style has exploited the elements and logic of postmodern dance - and not only in her earliest pieces. ''As Time Goes By,'' with its nonhierarchical order, was choreographed for constantly shifting partners in 1973. ''Deuce Coupe'' (1973) mixed the styles of popular dance and ballet, in part demonstrating with notable irony the way classical dance is made - ballerina Ericka Goodman executed the vocabulary of ballet movements in alphabetical order. And later, in ''Sue's Leg'' (1975), Tharp had Kenneth Rinker spitting on the floor and rubbing his shoe in it to keep his traction, undermining the decorum of dance and the idea of the dancer's preternatural perfection. Not that postmodern movement itself wasn't caught in Tharp's gaze too. For the relaxed, almost improvised look of many of her dances appeared as programmatically loose as early postmodern work when it was actually as tightly rehearsed as ballet. Beyond these typically self-critical postmodern elements, Tharp's special manner of calling attention to the nature and history of dance by grafting all sorts of idioms together has a more intriguing significance.
Consider the broader cultural framework. In the March Book Review section, I discussed the shift from modernism to postmodernism: the replacement of modernism's notion of fragmentation, whose fragments always refer back to their historical origins, with the idea of the gram, which doesn't reach down into history but across its surface, appropriating period styles and attitudes to create hybrid artifacts. And consider this practice of pastiche in the light of a more expansive cultural behavior: the influence of a pervasive technology, which reduces all information to equivalent electronic impulses in computer networks; a culture whose meeting place is the shopping mall, where the natural world is replaced by an enclosed layout, a network of products in endless juxtapositions and combinations; a visual culture whose primary source is the television, which brings the world closer by reducing it to an artificial scale that drastically reorganizes geography, time, and the divisibility of people(s).
Arguably, Tharp's dance is radically postmodern not only because of its involvement in certain practices of dance but because of the methods of representation it shares with our commercial society. Tharp doesn't present ballet or jazz, she gives us a pastiche of likenesses dramatically reorganized in a new hybrid form. By mimicking and grafting diverse dance styles, she reproduces them not as originals but as endlessly juxtaposed and combined copies. Here Tharp truly represents our society, which, as the German critic Walter Benjamin prophesied, can no longer tolerate the enormous flow of information and so desires ''to overcome the uniqueness of every reality by accepting its reproduction.''
Tharp's new dances at the Brooklyn Academy of Music seem more than ever to be about reproductions and the sensibility that creates them. ''Bad Smells,'' for example, is a work for seven dancers who appear to be victims of a cataclysm that has reduced them to brutish, tribal behavior. This apocalyptic fantasy is reproduced as it takes place, for a video cameraman (dancer Tom Rawe) follows the troupe around, projecting its images on a huge screen above the stage. The audience must constantly choose between the dancers and their video representations, between likenesses and originals. But Tharp is also using video's technique of representing the action to comment once again on the classical representation of the dancer's body as a silhouette, as an object in a two-dimensional tableau. The video literally flattens the dancers out on the screen, shifting their scale and cropping them so that they're broken up into heads and torsos, into the two-dimensional objects that the ballet form implies. This technological update of the classical tableau is a dance about another image of dance that it grafts, that is actually superimposed on it.
When Banes finally disqualifies Tharp because she has moved into the arena of ballet and film and no longer uses ''popular dance forms in an avant-garde context,'' she is really protesting Tharp's preference for a world that embraces imitations of reality, reproductions rather than originals. It's the fact that Tharp makes dances for the commercial world, for the commercial theater and all that is associated with it: spectacular sets, dances without seams, a dance of surfaces. But it's the nature of postmodernism to appropriate surfaces, to mimic and reorganize reality, to reproduce originals with teeming likenesses just as our commercial centers and popular media do. Remember that postmodern dance wanted to let more of the world in. By what prejudice, then, should the commerical world be left out? In fact, Tharp's commercial context may be the most telling of all. And what it tells us is that the old idea of the avant-garde rebelling against society by negating its values outright is a limited perception - one that has less and less to do with postmodern artmaking today.