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How do questions about identity relate to time and change?

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Marble bust of Aristotle with a beard and draped robe, showing detailed facial features and wavy hair, set against a dark background. — metaphysics Detail of a Roman copy (2nd century bce) of a Greek alabaster portrait bust of Aristotle (c. 325 bce); in the collection of the Museo Nazionale Romano, Rome.

In metaphysics, questions about identity are deeply intertwined with the nature of time and change, primarily through the problem of persistence—how an object remains the same entity while existing at different moments.12

Persistence and Change

When an object changes its parts or properties over time, it challenges the principle of identity. For example, the ship of Theseus illustrates the difficulty of determining if an object remains the same after its components are replaced. Similarly, personal identity questions whether a person remains the same despite physical or psychological changes.34

Rival Theories of Persistence

Metaphysicians generally categorize accounts of how things persist into two main theories:

Perdurantism: This view treats time as analogous to space. It posits that objects are "space-time worms" composed of temporal parts that exist at different times. Change is explained as an object having different properties at different temporal segments.1
Endurantism: This view argues that time is fundamentally different from space. It maintains that a persisting object is "wholly present" at every moment of its existence, rather than being divided into temporal parts.1

These debates are essential for understanding how we reconcile the intuition that objects endure through time with the logical requirements of identity.41