In March 2009, a few days before a major exhibit of Andy Warhol portraits opened at the Grand Palais in Paris, the curator faced a minor crisis. Pierre Bergé, the partner of Yves Saint Laurent and keeper of his legacy, objected to having the late fashion designer's portraits grouped with the likes of Giorgio Armani and Sonia Rykiel under the heading "Glamour." Saint Laurent was an artist, Bergé said. His image should hang with those of David Hockney and Man Ray. After all, Mr. Bergé said, Warhol himself had proclaimed YSL "le plus grand artiste français de notre temps."

Yves Saint Laurent camel coat with nutria-fur sombrero, 1962. Getty Images

The show went on, to glowing reviews, without the Saint Laurent images. It was an irony-drenched and very French moment, all about maintaining the status distinctions that Warhol himself had exploded. This was, after all, the man who famously compared department stores to museums. "Why do people think artists are special?" Warhol once said. "It's just another job."

Absurd though it was, Mr. Bergé's protest expressed a widespread conviction: that fashion is an inferior, unworthy, trivial and culturally suspect pursuit. Art is much, much better. In museum circles, observes Valerie Steele, the director of the Museum at the Fashion Institute of Technology, "Fashion is really seen as the bastard child of capitalism and female vanity."

So Sept. 9, when Mercedes-Benz Fashion Week opened at Lincoln Center, marked a significant cultural moment. The performing arts complex is doing more than providing a venue for runway shows. (You can, after all, rent its facilities for a bar mitzvah or corporate conference.) The center has hired a director of fashion and will incorporate fashion, along with opera, theater, dance and music, into its year-round lineup of featured arts, with plans for fashion films, photo exhibits and lectures.

Alexander Wang show, February 2010 Chris Moore/Catwalking/Getty Images)

It's a high-profile indicator of an intellectual trend that has been building for decades. Fashion is shedding its cultural stigma. It is increasingly recognized as a significant cultural activity—indeed, one of the defining characteristics of our civilization.

"Fashion attests to the human capacity to change," writes the French philosopher Gilles Lipovetsky in "The Empire of Fashion: Dressing Modern Democracy," his iconoclastic 1987 book. Like science and industry, "fashion is one of the faces of modern artifice, of the effort of human beings to make themselves masters of the conditions of their own existence."

Fashion allows individuals to create public images for themselves and to enjoy the pleasures of imagining those images. Against both custom and classicism, fashion reminds us that the pleasure of novelty is a human universal, both served and intensified by modern commercial culture. Though the fluctuations of Western dress date to the Middle Ages, fashionable variations become more frequent and less predictable as societies move away from inherited status and customary authority toward the fluidity of markets, social equality and republican government. The recent return of big shoulders to women's clothes is thus a tribute not merely to the 1980s, the 1940s, or men's suits but to the creative dynamism of an open society.

Derek Lam, February 2010 Photo by Chris Moore/Catwalking/Getty Images)

In its broadest and deepest meaning, fashion specifies no medium. It refers to any aesthetic change for its own sake. Painting and sculpture reflect changing fashions. So do music and dance, poetry and prose.

Fashion simply means that "something is now more attractive than what was previously deemed attractive," writes the Harvard sociologist Stanley Lieberson in his 2000 book, "A Matter of Taste: How Names, Fashions, and Culture Change." Camel-colored clothes look perfect this fall, while two years ago, purple was the color of the moment.

This fickleness makes fashion suspect. To rationalize it, two centuries of intellectuals have agreed, with slight variations, that fashion serves a basic purpose: to signal and enforce social status. Fashion was equated with conspicuous consumption and represented envy, snobbery and waste. The lower orders copied their betters, and fashion changed as the upper class sought to separate itself from its less prestigious imitators. Styles of music and painting might evolve in pursuit of truth and ultimate form, but the fluctuating styles of skirts or sofas were seen merely to entice the gullible or put down the hoi-polloi.

The youthquake of the early 1960s destroyed this simple trickle-down theory, as the populist styles of Carnaby Street displaced Paris haute couture. Mod girls in miniskirts weren't emulating aristocrats. The influence went the other way. In fact, the same was true of Coco Chanel in the 1920s. She became a couturier not by giving the rich what they already wore but by marketing the simple styles she liked herself. The appeal of fashion is far more complicated than class envy.

Take fashions in children's names. In the 1960s, Susan and (with various spellings) Cathy were among the most popular names for little girls. Today, Susan isn't even in the top 500, and little girls named Katherine are called Kate or Kit or Katie or Katherine—anything but Cathy, which belongs to women of a certain age. Some names just sound right at the moment, while others feel out-of-date or, like vintage clothing, attractively old-fashioned and perhaps due for a revival. Fashionable fluctuations increase, notes Mr. Lieberson, when parents feel freer to select their children's names, rather than honoring a saint or relative.

Rather than simple class emulation, fashions of all sorts seem driven by the desire to be different but not too different—to stand out as an individual while fitting into whatever group you identify with. Kayla, a popular name among lower-income whites, has never been in the top 20 among high socioeconomic groups. Goths and rockers have fashion cycles, and stylistic subgroups, of their own.

In dress, the fluctuations aren't random, nor do they mirror current events in some literal way. Styles of dress, like styles of music, evolve according to an internal aesthetic logic of their own. Hemlines react to last year's hemlines, not this year's stock market, and any given look can support several different, often contradictory, stories. Does economic hardship suggest somber colors, to reflect the public mood, or bright colors to cheer people up? The answer lies in whatever the subjective eye craves.

Heard on the Runway News and buzz from New York's Fashion Week

Incorporating fashion into Lincoln Center not only recognizes the cultural significance of this visual medium. It reframes fashion as a performing art, a more appropriate category than the static displays of a museum. Performances depend on the particular bodies of the performers. The difference between a flirty skirt and a slinky dress, or the drama of a cape versus the mystery of a trench coat comes from how the garments fit and move. That's why a model's walk is as important as her look.

Nor do models have a monopoly on fashion performance. In "Seeing Through Clothes," her landmark 1978 study uniting fashion with art history, Anne Hollander argues that clothing provides the basis for the most universal of performing arts. "A simple public procession of specially dressed-up ordinary people is one of the oldest kinds of shows in the world; it has probably continued to exist because it never fails to satisfy both those who watch and those who walk," she writes. Whatever the theory of the moment, the pleasures and artistry of fashion endure.

—Virginia Postrel is the author of "The Substance of Style" and the editor of DeepGlamour.net. She is writing a book on glamour for the Free Press.