 One of the most central kinds of sortal, and one of the most difficult to give uncontroversial examples of, are the persistence sortals. A persistence sortal is one where, if the sortal is no longer true of the object, the object no longer exists. If a car is crushed into a metal cube, the car no longer exists. But if the car is transformed into a boat, does some one thing exist first as a car and then as a boat? According to some views, when someone dies they cease to exist; according to various other views, the same person may be reincarnated in a new form. Is a werewolf sometimes a person and sometimes a wolf, or are they always a werewolf and neither a person nor wolf. 