Art will always keep its biggest secrets buried in mystery. But there's a but. Throughout time, art's take on female beauty has been unambiguous. The archetype of allure is the passive nude: armless (as in Venus de Milo), or dormant (as in "Sleeping Venus" by Giorgione).

In case you think this ideal is the stuff of history, witness photographer Irving Penn's current show at the Met in New York. If, as historians tell us, art is a statement of a country, a culture and a person, Penn's photos of nude females are straight out of the Neolithic era. "Nude #1" shows a heavy-set model with her arms behind her back, similar to the Venus of Willendorf, circa 24,000 B.C.

The curator of the show, Marie Morris Hambourg, recognized the similarity between "Nude #1" and the Venus of Willendorf in Art News this month. She called Penn's example a "timeless fertility goddess." The artist, she said, is "in touch with the same instinct that called forth that Venus from her Neolithic sculptor–the recognition of the mysterious, procreative power of the female body that has symbolized creativity since the dawn of art."

To read Hambourg's words and regard Penn's images, you'd think that the female was a vessel without volition. One may wonder how an armless Mother Earth could cradle the life she bears, let alone nurture it. Fully acknowledging the absence of limbs and heads in Penn's work, the curator added, "Penn's figures are always complete in their partiality; although they lack limbs and heads, they seem whole, like fragmented antique torsos resplendent in the light."

What Penn doesn't know about women could fill a Germaine Greer book on male chauvinism. What Hambourg doesn't know about art history is a head-scratcher. Between the two of them, you'd think that Edouard Manet never painted "Dejeuner sur l'Herbe" ("Luncheon on the Grass"). The painting defined the moment when traditional art turned modern, and the passive woman stirred.

The painting portrays a nude woman picnicking with two clothed men in a Paris park. Nothing new there. Lots of Old Master paintings feature clothed men and unclothed women. The difference is that the female boldly stares back at you, as if you're intruding. Her hand is tucked under her chin in a thoughtful, questioning pose. "Yes?" she seems to ask over her shoulder, her face direct and challenging.

Her active participation in the painting rocked high Parisian society. Even Emperor Napoleon III, himself no model of decency, called it "indecent." But it wasn't the female's nudity in a public place that offended. It was her face, which lacked the usual demure reticence of naked females.

Another thing: Manet's female model was neither allegorical nor mythological. She was a well-known model of her time and a painter in her own right–Victorine Meurend, who ran off to America with her lover after Manet finished the painting. Talk about volition.

The way Penn and Hambourg think, you may imagine yourself back in the 19th century, when everyone was reading a particular domestic guide. "The Daughters of England: Their Position in Society" warned a woman not to strive in any direction, because it "would tend to draw away her thought from others and fix them on herself (and) ought to be avoided as an evil to her."

Penn's images, along with all the passive nudes in history–those countless unconscious women sprawled over time like so much spilled paint–could be illustrations for the domestic guide of two centuries ago.