The Erwin Wurm retrospective at the Frye Art Museum does not include a 1970s-vintage orange Volkswagen van that looks like it has been picked up by a monster and bent almost into a C. The van is in Vienna, in another Wurm retrospective. In a letter mounted in the window of the van and addressed to an Indian telekinesis guru, Wurm's assistant requests help, explaining that the artist wants "to make sculptures only by using thoughts." In the next letter is the guru's reply, that he can do it, given that he gets $2,000 and a business-class ticket to the site of the VW, and that the electricity is turned off while he works.

In a packed lecture at the Frye on November 18, the Viennese artist declined to say how the sculpture was finally made. Of course: The van is testimony in Wurm's ongoing investigation into the unresolved relationship between thinking, doing, and being. Wurm has spent his entire career positing that sculpture is not limited to being, but can be interested in thinking and doing, too. This isn't a new idea; it spans back through fluxus and conceptual art to—who else?—Duchamp, with his readymades and instructional art. But Wurm is wicked, wicked smart, and versatile, and in his time he has created a few whoppers that will continue to mark him as a major player in the playful lineage of conceptual sculpture. Those include the video of a fat, marshmallowy house pondering its own pathetic existence, and the dark, drug-addled babble of the overweight car in the video I Love My Time, I Don't Like My Time.

And while it gets tiring at the Frye looking at 18 photographs of One-Minute Sculptures and 50 drawings from the Thinking About Philosophy series, there's a point here: One sculpture can take any number of forms. When you sit on the white pedestal and follow Wurm's instructions to hold your breath and think about Spinoza, you'll look and be different from the next person holding his breath and thinking about Spinoza. What does it look like to think about the French theorist Jean Baudrillard? Wurm shows us, in a pencil drawing called Thinking About Baudrillard. (It looks like Thinking About Buddha, but without the scarf.)

The dualism of interior and exterior, unique to three-dimensional art, is another of Wurm's preoccupations, and he uses it to explore philosophical questions about sculpture as well as timely political, social, and sexual issues of security. In Inspection, a man sticks his head down the sweater of a woman having lunch at a fancy restaurant. She may have a bomb in there, or a stash of liquid deodorant. In The Artist Begging for Mercy, Wurm is kneeling and praying, with a lemon in his mouth. In the context of sculpture, this photograph emphasizes the peculiar and enduring human belief that it helps to arrange your body in particular positions if you want certain external things to happen.

Wurm has a horde of admirers, largely for the liberating One-Minute Sculptures, which can be performed by anybody. For instance, if you want to stick your legs out of your house window, you can, but Wurm requests that you please do it at 8:00 a.m. You don't have to hold it for a minute; just a few seconds will do. Famous people and advertisers alike dig these. It is a pleasure to see Flea with pens in his eyes and a stapler sticking out of his mouth in the Wurm-inspired (and Wurm-credited) Red Hot Chili Peppers' 2003 video Can't Stop, which plays as you come in the door of the Frye. For Wurm, it was less of a pleasure when the Gap stole one of his ideas for an ad. He's all for infinite reproducibility—to a point. Me, too. I like it best when his art is both anonymous and personal, rather than iconic and allegorical. I'd rather not stick a chair leg in my eye socket, but I'd love to stuff my body into one of the oversized sweaters lying on the pedestal in the entry to the Frye and just assume the various positions, my body becoming an unfamiliar abstraction that's nonetheless utterly mine.

Wurm has made out with museum curators before, in a series on the power of museum professionals, and here we get a portrait of a fattened-up Robin Held, the Frye's curator. He always returns to everyday concerns, though. "To make a sculpture is to work on volume," he said in his lecture. "To gain or lose weight is to work on volume. Therefore to gain or to lose weight is to make a sculpture." It's just another idea in the quest to figure out how sculpture might relate to action instead of commemoration, and to life instead of death.