What is the correct theory of personal identity over time?

Are you the same person you were ten years ago? Psychological-continuity views, biological views, and narrative views give different answers — and disagree in cases of split brains, teleportation thought experiments, and gradual cellular replacement.

Derek Parfit argued that personal identity may not be what matters in survival; others defend essentialist views. The debate connects to ethics, law and emerging technologies like mind uploading.