Is it design or art? This is not a philosophical question. In the material world—the world of the art market—the answer has a precise practical consequence. If design is an applied art, if a chair is meant to be sat on, then it remains an object, a mere object. But if the chair is conceived as a sculpture, if its function dissolves entirely in favor of beauty or a certain radicality, then it takes on a noble character and commands a higher price.

Of course, all of this is a matter of convention. And the convention that allows us to see art where doubt might otherwise exist leads to a willingness to appraise it more highly—and therefore, to pay more. For in today’s art market, structured in a strangely rational manner, desire is heightened by pieces produced in limited editions and numbered accordingly…