This was Arte Povera's pragmatic side, its most practical lesson. There is a constant complaint nowadays that you can't tell the difference between the art and the packing, the mess and the message. Arte Povera invested everything with meaning and resonance, however slight some of its gestures. If nothing else, it was an art of promises - it depended on faith and on a suspension of rules as much as of disbelief. The work still looks fresh, even if much of it has now acquired the patina of age and of sanctified art, which is the fate of all art, even the most dematerialised, the most ephemeral.
Ideas bounce off each other, objects and images and artists have conversations again.
As much as anything else, this show will help us forget the horrors of Tate Modern's Century City. We can worry, at last, more about the art, and less about the institution that houses it. Yet Arte Povera remains nothing if not demanding. It was an art of potentials and energies, of transfigurations, labyrinthine and untranslatable metaphors, experiments with materials, forms, spaces and language. Arte Povera comes with its own built-in barriers, as well as the ones the Tate will erect to keep the audience at bay.