Not long ago, in a warehouse loft in SoHo, Isaac Mizrahi presented his spring collection up on a catwalk long enough to satisfy virtually every fashion editor who wanted to be in the front row. Sunglasses in place, the editors looked indifferent as models strode by in culottes, Puritan blouses and patent leather baseball jackets. Midway through the show Mizrahi sent out a group of linen dresses in Easter egg pastels, their layered collars rising chinward in a volcanic peak. If the models' pretty heads looked slightly decapitated, the editors' faces told another story.

They were not amused.

A week later, at a dinner in Washington to open the Anthony Van Dyck exhibit at the National Gallery, guests observed a very different fashion show, displayed in 17th-century paintings. Van Dyck's high-born subjects, even the odd dwarf, wore the most conspicuous clothes of the era, not the least of which was the ruff. This round collar served as a kind of starched platter upon which the head sat, or so it appeared. Had the art guests also seen Mizrahi's modern-day ruffs, they might have wondered if deformation was back in style.

At least they would have gotten the joke.

People rarely go to art galleries to look at clothes, but if you think about it, the Van Dyck exhibit is also comparable to a mall: Fashion is on parade. Young men who hang out in torn blue jeans and sprouting dreadlocks, for example, are the sartorial descendants of Thomas Killigrew, who posed for Van Dyck in 1638 wearing slashed sleeves and a lopsided cascade of curls. Like today's dreads, these uneven locks were not just peacock vanity. They signified that Killigrew was in love.

Van Dyck's paintings are filled with such deliberate gestures and, more than one might suspect, they are the same fashion gestures that people use today to express status, taste and anti-fashion attitudes. Sometimes the connections are literal, such as Mizrahi's collars, but more often they are figurative, such as "lovelocks" and slashed clothes. Either way, Van Dyck's paintings offer yet another means of understanding why we dress the way we do.

If fashion editors glower at dismembering necklines in SoHo, their disapproval is no match for the scorn heaved upon ruffs in the early 17th century. In the 1616 murder trial of Frances Howard, accused of poisoning her impotent ex-husband, her ladyship's accomplice, a Mrs. Turner, was harangued for -- and eventually hanged in -- her yellow ruff. In the same way that pantyhose made miniskirts more wearable in the 1960s, the advent of starch in the 1560s gave rise to the "great and monsterous Ruffes" denounced by Philip Stubbes, a Puritan who managed to find evil in practically everything fashionable.

The "bigger is better" theory of conspicuous consumption (from pyramids to limos) was advanced by Van Dyck's patrons too, especially in their ruffs. Susanna Fourment, painted in 1620 or 1621 with her daughter, wears a birthday-cake-size ruff edged in lace. "This was really quite excessive," notes Edward Maeder, curator of costumes and textiles at the Los Angeles County Museum of Art. Lace was not only expensive -- desirable enough to be force-fed to cats in Flanders and removed from their bellies in England, where it was contraband -- but regulated by sumptuary laws designed to enforce class distinctions. Madame Fourment was simply showing off her class.

Maeder believes that ruffs also came into fashion as a symbol of enlightenment. "It was the platter upon which the head of reason sat," says Maeder. "The head was considered the most important part of the body, and a ruff called attention to it." Less enlightened but just as fashionable was the practice of bleaching one's complexion with a solution of white lead or borax, reddening the cheeks with crystalline mercuric sulfide and sealing everything with a glaze of egg whites. This look was cosmetically revived in the '70s, and can be seen on video in "The Eyes of Laura Mars."

Whenever we see someone in bondage straps and fetish platform shoes -- the kind of look proposed by Jean-Paul Gaultier a few years back -- we are apt to question their morals. A woman who wears head-to-toe Chanel may be advertising her wealth, but she is considered a fashion victim. Morality and status are long-running fashion themes. In her excellent book "Dress and Morality," Aileen Ribeiro, head of the history of dress department at the Courtauld Institute in London, describes public attitudes toward fashion at the end of the 16th century: "Never was there such a period when the bright, distorted and glittering dress of the fashionable woman was thought to reflect the shallowness of her soul, her essential immorality." Likewise, we now regard Christian Lacroix's poufs as bloated chic and wonder why so many women allowed themselves to look like demented dolls.

Van Dyck's subjects were apparently not as gullible, or at least not so obvious. If anything, they convey a blue-blood air of bookish dishevelment, an affectation we now call "dressing down." Ralph Lauren does this in his advertisements, in which female models wear expensive tweeds with denim work shirts and lean against vintage woodie station wagons. In a similar way, Susanna Fourment wears a plain dark vest over her gold-flecked gown "to tone it down," says Maeder. "This may have been the influence of the Puritan ethic." Today, people "tone down" Armani suits with Gap T-shirts and offset romantic blouses with mannish suits, as Romeo Gigli does. This is the anti-fashion ethic at work.

Ribeiro suggests that the Puritans, in adapting the Spanish preference for black, may have introduced "the first real anti-fashion for men." Van Dyck put a black coat over a plain white shirt for his own portrait, as did Thomas Killigrew and William, Lord Crofts, for theirs in 1638. But anti-fashion wasn't, and isn't, limited to black. James Stuart did not neglect to smooth the wrinkles out of his white stockings when he stood for his portrait in 1633. "You have to keep in mind that every gesture was deliberate, and not Van Dyck's interpretation," says Maeder, who surmises that Stuart, in his taffeta cloak, snowflake lace collar and baggy hose, "must have been the chicest of the chic."

Cool is the man who would be a slob. It is more fashionable to wear a knackered leather jacket than a new one, more hip to schlump around in unlaced sneakers than show the faintest awareness that they might be hazardous. In the 16th century young German soldiers slashed their sleeves into ribbons if for no other reason than to be avant-garde. Today's young fashion barbarians are really not so different from the German landsknechts, except that they get their slashed clothes at Issey Miake and Vivienne Westwood.