derivability requires all of an exercise's sources

agent-decided, reversible. An exercise that supersedes several authorities at once inherits from all of them, so the successor is certified only when every source is. The alternative — one certified source suffices — admits a successor of a manufactured authority and an earned one whenever the merging act itself survives the challenge.

The decision could not be taken inside this repository's own architecture: Reflective Integrity's G6 refuses a supersession whose target is absent, so a merge whose sources do not all survive is inadmissible anyway and the two rules agree everywhere. A register of offices and appointments, which has no such precondition, separates them and is what settled it.

Rejected alternative: existential inheritance, under which a lineage through the clean half of a pair carries the pair.

Record: projects/normativity/legitimacy/rounds/2026-08-25-legitimate-evolution/COUNTERMODELS.md §5.