Most Americans takeit for granted, as well they should, that in a democracy, the experience of going to an art museum should be made more widely accessible. But any museum that starts down the twisty road of cultural democratization can lose sight of its overarching mission. Besides making great works of art accessible to the public, that mission consists of preserving their treasures and teaching its visitors how best to look at them. This last involves deploying the expertise of its curatorial staff in the service of defining what it means to call art "great." Yet I've been to more than a few museums whose patrons were so busy dining in the café, listening to noontime concerts and shopping for knick-knacks that scarcely any of them bothered to look at the art on the walls.

How can established museums reach out to new viewers without compromising their time-honored function? One approach is now being tried out at the Clark Art Institute of Williamstown, Mass., which has just launched a program called "uCurate." Visitors to the Clark are invited to download a digital app that allows them to design imaginary art exhibitions made up of pieces in the museum's permanent collection, then enter them in a competition whose winners get to install their shows in a gallery at the Clark with the help of the staff.

The Clark's first uCurator is Giselle Ciulla, an 11-year-old girl who has put together a show called "Giselle's Remix," which consists of 18 paintings, sculptures and objets d'art by Corot, Degas, Renoir, Winslow Homer, George Inness and others. She has also written the wall labels, of which this one, for Homer's "Sleigh Ride," is representative: "I like how the only thing is the sleigh, like nothing else is alive, just the horse and the rider."

It's easy to see what the Clark, an admirable but decidedly unsexy institution whose conservative collection consists in the main of 19th-century French paintings, is up to. "Giselle's Remix"? "uCurate"? We're talking young here. The program might as well be called "U 2 Can B a Curatr." And Michael Conforti, the Clark's director, is laying it on with a palette knife. "The chance to work with a young person whose eye and curatorial instincts are so engaging gives us a great way of showcasing new perspectives," he says. "I can't think of a better way to launch the first of our uCurate exhibitions than by inviting the next generation to take a leadership role."

Now that the concept of artistic "greatness" has become a political football, many museum curators are reluctant to fulfill their traditional function of helping to define it. I doubt that anyone at the Clark was thinking about cultural relativism when they invited Giselle to install "Giselle's Remix," but I'm dead certain that Gary Vikan, the director of Baltimore's Walters Art Museum, was up to his ears in it when he proclaimed the glories of "Public Property," a recent show whose contents were chosen by the people of Baltimore. "At a time of increasing concern about equity and democracy within society, from the Occupy Wall Street movement to the Arab Spring, I've been thinking more about the role of museums not only to act as expert but also to encourage civic participation in our exhibition process," Mr. Vikan said. Translation: You fine folks may not know anything about art, but you know what you like, so let 'er rip.

Color me skeptical. While I'm all for encouraging kids to pay regular visits to museums by just about any means necessary, I don't think we should ever pretend, as the Clark is doing, that they have anything noteworthy to say about the art therein. They come to learn, not teach. Just as no child can possibly know enough about life to write a halfway decent novel, so can no child, even one as palpably bright as Giselle, know enough about art to curate an exhibition that merits the sustained attention of adults.

As for people's-choice shows like "Public Property," they're pure PR gimmickry, the kind that degrades any institution that stoops to it. Yes, great art is for the people—but it's made by individuals, not committees, and there's no such thing as a great committee. In the eternally and increasingly relevant words of W.S. Gilbert, "When everyone is somebodee, / Then no one's anybody!" Without such miraculous "somebodees" as Winslow Homer, the rest of us would be doomed to live in a world of mediocrity. Instead, we can all hope to be ennobled by contemplating the fruits of their genius, guided by experienced men and women who've spent their whole lives looking at and thinking about art. That's what museums are for.