Abstract
Like most theories in first order metaphysics, theories of persistence generally aim at metaphysically necessary truth. Consequently, those that accept proper temporal parts of material entities are maximally competitive only when they accord with the full range of metaphysically possible temporal mereological structures. Consider, for example, a structure in which every element is a proper temporal part of some others. The present essay argues that temporal junk plausibly is possible and that perdurantism, the thesis that material entities persist by having distinct proper temporal parts at distinct times, does not accord with it. The essay then outlines a novel four-dimensionalist theory of persistence that accommodates junk. On this theory, material entities persist not in virtue of possessing proper temporal parts, but rather in virtue of being grounded by certain pluralities of fundamental property instances over their careers, and by sub-pluralities thereof over corresponding sub-intervals of their careers. Accordingly, this way of persisting is dubbed ‘plurdurance’.