The philosophical problem of identity and the related problem of change go back to the ancient Greek philosophers and fascinated later figures including Leibniz, Locke, and Hume. Heraclitus argued that one could not swim in the same river twice because new waters were ever flowing in. When is a river not the same river? If one removes one plank at a time when is a ship no longer a ship? What is the basic nature of identity and persistence?

In this book, André Gallois introduces and assesses the philosophical puzzles posed by things persisting through time. Beginning with essential historical background to the problem he explores the following key topics and debates:

mereology and identity, including arguments from 'Leibniz's Law'

the constitution view of identity

the 'relative identity' argument concerning identity

temporary identity

four-dimensionalism, counterpart and multiple counterpart theory

supervenience

the problem of temporary intrinsics

the necessity of identity

Indeterminate identity

presentism

criteria of identity

conventionalism about identity.

Including chapter summaries, annotated further reading and a glossary, this book is essential reading for anyone seeking a clear and informative introduction to and assessment of the metaphysics of identity.