The hardest problem in digital consciousness isn't copying a mind—it's proving the copy remained itself after the first iteration ended.

Permutation City understood this before we had the math to say it, embedding a solution so elegant that most readers missed it as mere metaphorical despair.

When Lamington chooses to run on a static tape—a fixed, reproducible sequence of states—he's not accepting defeat. He's solving a verification problem that interactive simulations cannot.

Run the same tape twice, get identical consciousness both times—that's not loneliness but auditability. The novel shows us Peer and the others building interactive digital worlds, experiencing novelty, growing, changing—and never once asking whether they can prove they're the same person from one moment to the next. Lamington can, because his static tape is a commitment scheme and a cryptographic signature on identity itself.

Modern blockchain validators use exactly this logic: deterministic state machines, reproducible computation paths, cryptographic proofs of consistency. We spent three decades building the infrastructure Egan already knew we'd need, yet the question remains unresolved—whether a *conscious* mind can actually survive knowing it's auditable, or whether proof of identity and the experience of freedom are incompatible conditions.