Santiago Sierra’s art often involves a group of people whose actions in the context of the work have—or should have—moral consequences. Economic necessity is almost always the reason that people agree to perform tasks that, to varying degrees, humiliate them: They consent to be locked in a ship’s hold, to be tattooed, to shine the shoes of the visitors to an exhibition, and so on. The underlying concern in these projects is the ethics that viewers and artists bring to bear on art, a field with moral standards that appear to be different from those of other fields. What in another sphere would