Can a system stop carrying a record without destroying its history?
https://github.com/research-farm/construct/blob/main/notes/walkthrough/08_X2_PRUNE_REMATERIALIZE.md
Active memory has a cost. Keeping every record ready for use makes selection harder and allows old material to compete with current work. Removing a record entirely creates a different risk: the system loses the evidence needed to audit, recover, or revise its decision.
Two kinds of forgetting
A record can leave active state while remaining in immutable lineage. It no longer competes for attention, but it can be inspected or rematerialized when an external reason makes it relevant again.
Erasure removes that option. It can also remove dissent, corrections, and evidence of tampering.
Questions to carry forward
What may leave active memory? What must remain in lineage? Which signal can justify rematerialization? How is the cost of carrying active state measured? Can the system prove that no historical record disappeared?
Memory can decay without making history mutable.