If the message expressed in a piece of fine art is as important as the image itself, then it makes sense to look for beauty in graphic forms not traditionally included in museums. And as the 20th century draws to a close, now that everything from urinals to accidental sketches have found their way into the museum world solely because they are dubbed "fine art," perhaps it is time for the museum world to take the next step and open up to art never intended for the gallery.

If one such candidate for new critical acclaim is commercial art, graffiti is the democratic underdog. It presents itself on a daily basis to almost anyone living in a city. Of course there are reasons why Museum of Modern Art (MoMA) curators don't run down to the grafitti streets with open arms. Graffiti is one of the most objectionable forms of art, as it can be difficult to distinguish between creativity and malicious vandalism.

Some would hesitate to even call graffiti art--the law treats anything painted on a surface without the owner's permission as vandalism. But other members of the art world see a strange beauty in walls and doors scarred by markers and spray paint. The curators of the Trustman Gallery of Simmons College, near the Isabella Stewart Gardner Museum, have even had the good sense to devote an exhibtion to tag art: Graffiti is running through the end of the month.

Exhibiting graffiti is not a new idea, but the Trustman exhibit takes a fresh look at "a global art movement with origins in urban hip hop culture." The show's curators, Bob Oppenheim and Matt Clark, attempt to put Boston graffiti "in context," examining the motives of graffiti artists and writers. Inspired by a paper written by his late son, Josh, Oppenheim says the purpose of the show is not just to exhibit graffiti, but to win over the public as well.

While the focus is on Boston area graffiti, graffiti is not a unique phenomenon in each city; many of the activities and concerns of writers around the world are very similar. Today's urban graffiti has its roots in the New York of the early '70s. It is a worldwide phenomenon, visible in almost any city or town, with new styles and movements developing and spreading out of the cities.

It is easier to accept graffiti as art after seeing it in a gallery. The exhibit itself consists of collected photographs of Boston-area graffiti from the late '80s to the present day, along with various graffiti-covered doors and windows. A few of the pieces look as if they might be found in the Guggenheim rather than in an exhibit on street art, and such similarities with other forms of contemporary art support the argument that graffiti might indeed be a "real" art form.

Playing in one corner of the exhibit is a video produced especially for Graffiti. Filmed and edited by Stephanie Homan, Writers is a tour of different graffiti sites in the Boston area. Wombat, an experienced Boston area graffiti writer, leads the tour. He also explains some of the history of the Boston graffiti scene.

One of the best and most accessible aspects of Graffiti is the web site, designed by Evelyn Kofler. Some of the photographs included in the exhibit can be found online, along with the full text of the interviews conducted with Boston area graffiti writers. The interviews are wonderful to read and very enlightening, as they go into great detail about the stylistic movements, terms, tools and behavioral codes of graffiti writers in Boston and in general.

The video and web site are integral parts of the exhibit. The difficulty of recreating a scene on the street in the gallery, or even just photographically representing one, is overcome with the help of these two innovative media. Both give the exhibit the "street cred" to ask our question: Is graffiti really art?

Some would argue that it's vandalism, pure and simple. In the most literal sense, graffiti is a set of markings that, if nothing else, informs the world of the writer's presence. As demonstrated by the Trustman Gallery's exhibit, today's urban (and suburban) graffiti is a mixture of tags (a writer's intricate and distinctive signature), throw-ups (a large design, usually of letters, done quickly to attract attention) and pieces (short for masterpieces, they resemble murals; an assorted collection of images and words). What these categories don't express is the potential difference between a 13-year-old scrawling his tag on bus stop benches and a graffiti writer who labors over his masterpiece on a legal wall.

The exhibit doesn't automatically assume all graffiti is art. Part of the complexity of the question "is graffiti art" stems from the illegal nature of its creation. The oldest artwork in the world, cave paintings such as those found in Lascaux, France, could be considered a form of graffiti. But more importantly, Lascaux, like grafitti, was someone's attempt to leave their mark, and in the debate over the merits of grafitti, such a point seems more important than legalities. Additionally grafitti is also a sign of anger, resentment, and a sort of liberation in defying society's laws. The creation of graffiti is as much a political statement as a physical act. The works cannot be considered independent of their function as social protest. In the eyes of the critic, the fact that grafitti is ultimately grounded in social reality underlines its importance as part of society's visual culture, while also underlining the irony of displaying grafitti to the gentrified, museum-going world.

As Oppenheim sees it, one of the best parts of the Trustman exhibit is that it raises these questions; "You're not asking, is graffiti art. You're asking, what is art?" It's true that this most unconventional (and original) of art forms forces us to reconsider what it is we value in visual art. If we need to argue over whether spray paint on a wall has the same merits as watercolor on a canvas, then we need to argue about art's very definition. And what is the definition? Is everything that is a visual form of expression a piece of art? The Trustman Gallery's video of graffiti sites around Boston and its interviews with graffiti writers will convince you that writers are serious about their craft. They may not think of themselves as professional artists, but the do try new techniques, take creative risks and take pride in their work, just as professionals would.

As for the Trustman Gallery show, it is a show that would be very difficult to imagine at Harvard. Luckily Simmons College was willing to take a chance on art that many people consider questionable at best. An exhibition like this performs a powerful service, rivaling the influence of a whole museum full of galleries. We see that graffiti does not simply alter the commonly accepted definition of art; rather, it shows how incomplete or impossible that definition is.

Josh Oppenheim's paper suggests that today's graffiti is a return to the purest form of artistic expression--sketches and scribbles on cave walls. Oppenheim's paper quotes a graffiti artist who claims that "the art on the streets are the real life galleries." The most basic expression of anger and pride may well come from the streets, but can the rest of us understand them? The paper also quotes ethnologist Robert Colombo as saying, "After reading kilometers of walls one realizes that, whatever its meaning, here is what it means to be human." Can we look past the broken laws and unsightly walls to see what's trying to be said? The greatest challenge of appreciating grafitti is allowing it to challenge the way the art world works.