ROBERT IRWIN IS NOT the art-world star that some of his contemporaries from the 1960s have become—think Andy Warhol, Sol LeWitt, Ed Ruscha, Nam June Paik, Vito Acconci—but in most respects he is as important as they were in revolutionizing the very definition of visual art. Before the ’60s, contemporary art consisted primarily of painting, with sculpture a distant second. Afterward, contemporary art seemed to be everything butpainting: performance, installation, body art, earth art, conceptual art, video art, artists’ books, photography, sound, and music. And though painting and sculpture have never truly gone away, today they compete within a carnival of forms and fashions that can seem chaotic to the uninitiated.
Critic Lucy Lippard famously explained the shift away from painting and sculpture in the phrase “the dematerialization of art.”…