Perdurance is one of the ways in which material objects can exist in time. This way of existing in time is of the special significance when the so-called 'Leibniz's Law' (the law of indiscernibility of identicals) is being applied to material objects undergoing changes in time. According to the Leibniz's Law, if two objects are identical, they can be ascribed exactly the same properties. However, an object existing before a change does not share all its properties with the very same object existing after a change - this is what a change consists in. The proponents of perdurance want to solve the above puzzle in the following way: an object is to be understood as composed of temporal parts, and to these temporal parts we can ascribe different properties, like 'being p' and 'being non-p'. In such a way, according to the proponents of perdurance, we can give an account of how a change is compatible with identity of an object. However, it seems that if the doctrine of perdurance is supposed to solve problems with identity through change, temporal parts must be understood as non-momentary (extended in time) and arbitrary (their ontological status cannot be superior to the status of objects). Otherwise the doctrine of perdurance is threatened by the so called 'no-change' objection, according to which there is no real change of perduring objects, since there is nothing to survive a change, as there are only successions of different objects, that is, successions of temporal parts.
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