perdurantist

Perdurantism, also known as four-dimensionalism, is a theory in the metaphysics of persistence that holds that persisting objects are extended in time as well as space. According to perdurantism, objects are four-dimensional spacetime worms composed of temporal parts or time-slices. An object at a particular time is not the whole object but one of its temporal parts; the entire object across its life is the series of its temporal parts.

Compared with endurantism (three-dimensionalism), which holds that objects are wholly present at each moment and persist by remaining the same whole across time, perdurantism treats persistence as the composition of parts across time. The Ship of Theseus, for example, is often used to illustrate how an object can change parts over time yet remain the same four-dimensional whole through its sequence of temporal parts.

Key ideas include temporal parts, stages, and the notion that identity over time can be captured by the relations among parts rather than by a single enduring form. Stage theory is a common perdurantist formulation in which the basic entities are instantaneous temporal stages; the enduring object is the sum of these stages.

Criticisms focus on the ontological burden of many temporal parts, vagueness in drawing boundaries between parts, and challenges from relativistic physics regarding simultaneity. Proponents argue that perdurantism offers a natural account of change and temporal identity by integrating objects into a unified four-dimensional framework.