Competing Theories

Philosophers offer several ways to think about identity over time. Spatiotemporal continuity says an object is the same as long as there is an unbroken chain of existence, even if its parts change.

Material composition theory argues that identity lies in the physical stuff, so the reassembled original planks form the true ship. Psychological continuity applies to people: you are still you because your memories, personality, and consciousness flow in an unbroken stream.