 If we could establish that things have temporal parts if and only if the past and the future exist, this would raise a number of issues. First, should we attempt to establish a theory of persistence, and then let this dictate our theory of time? Or should we start with the theory of time? (See  section 7  for an argument from physics against presentism and thus, perhaps, against endurantism.) Or can we somehow establish both at once? Second, tying the dispute about persistence to the dispute about time makes trouble for anyone who thinks that one of the disputes is genuine but the other is merely a verbal disagreement. And, third, since presentism and eternalism seem clearly to be incompatible, if each compels a different account of persistence, then there can’t be ‘mixed’ worlds in which some things perdure and others endure (a peculiar consequence, since most endurantists think that processes perdure).