perdurantism

Perdurantism is a theory of persistence through time according to which objects are extended in time and have temporal parts, or stages, just as objects in space are extended in space with spatial parts. Under perdurantism, a person, statue, or any object is a four-dimensional entity whose existence over time is a series of successive parts.

Each temporal part has properties appropriate to its time, and the whole object is the sum of its temporal parts. Identity over time is thus not a matter of a single object remaining identical at every moment; instead, the object is constituted by its parts across different times. Change is explained by differences among the temporal parts, rather than by the object undergoing replacement or only existing in the present.

Perdurantism is a form of four-dimensionalism and contrasts with endurantism, which holds that objects are wholly present at each moment and persist by remaining the same through time. Some philosophers distinguish the instantaneous stages from the four-dimensional object, calling this a stage theory; others describe perdurantism simply as four-dimensionalism. Exdurantism, sometimes discussed as a rival view, emphasizes becoming via temporal parts.

Common illustrations include a statue that erodes over decades or a person aging: each time-slice is a temporal part with its own properties, while the whole through time is the collection of all such parts. Debates focus on how to count parts, how to account for identity across time, and whether the theory entails counterintuitive implications about persistence and causation. The view remains a central option in metaphysical discussions of persistence and change.