When a tree is chopped to bits, or a sweater unravelled, its matter still exists. Since antiquity, it has sometimes been inferred that nothing really has been destroyed: what has happened is just that this matter has assumed new form. Contemporary versions hold that apparent destruction of a familiar object is just rearrangement of microparticles or of ‘physical simples’ or ‘world stuff’. But if destruction of a familiar object is genuinely to be reduced to mere alteration of something else, we must identify an alteration proper to the career, the course of existence, of this something else; relatedly, the alteration must be characterizable without asserting the existence of the familiar object. All contemporary views fail one of these requirements.