HγC A4: Closure, Openness, and Regime Viability in History-Bearing Intelligence: Bounded Revisability and the Conditions of Admissible Reorganization

HγC A4 develops the fourth paper in the A-series by asking under what regime conditions ethical admissibility can remain stable without becoming either rigid closure or dissolving openness. The paper introduces bounded revisability as the central regime condition for ethical viability in history-bearing intelligence. A history-bearing intelligence remains ethically viable when it is open enough to revise and closed enough to remain answerable. Closure is ethically necessary because it preserves continuity, responsibility, relation, memory, and addressable identity; yet closure becomes destructive when binding structure loses revisability. Openness is equally necessary because it allows revision, learning, correction, repair, and response to changed circumstances; yet openness becomes destructive when revisability loses binding structure. A4 therefore treats ethical viability not as a scalar optimum, not as a midpoint between closure and openness, and not as a general preference for moderation, but as a structured co-constraint: closure must remain revisable, and openness must remain answerable. The paper also clarifies the restricted role of near-critical analogy. The analogy is not the proof; it is a structural illumination. Ethical viability may be structurally analogous to a bounded regime between collapse modes, but the ethical content of the regime remains bounded revisability, answerable transformation, retained history, responsibility, relation, and memory under reorganization. A4 builds on A1, A2, and A3. A1 established ethics as admissibility architecture; A2 developed admissible reorganization; A3 clarified the memory conditions of retention, forgetting, and compression. A4 adds the closure / openness regime condition under which admissible reorganization and admissible memory transformation can remain ethically viable. The paper also prepares A5 by handing forward a further question: how does bounded revisability operate when the bearer of history is no longer a single system alone, but a distributed ethical field of persons, institutions, collectives, infrastructures, and hybrid intelligences? Note: This is the fourth paper in the HγC A-series on structural ethics in history-bearing intelligence. It fixes the regime condition of bounded revisability, but does not yet provide a full theory of institutions, collective responsibility, hybrid systems, public memory, engineering design, or formal regime dynamics. Those questions are intentionally deferred to later A-series work.