Structural Limits of Indistinguishable Ancestor Simulations A Representational No-Go Result

This paper establishes a structural constraint on descriptions arising from the joint imposition of global admissibility and local resolvability. Working at the level of representational roles rather than empirical systems, we show that no single description can simultaneously satisfy the conditions required for global completeness and unrestricted local resolvability. Ancestor simulations are characterised as selectively resolved descriptions that provide local resolvability within a bounded historical epoch or region while relying on compression or truncation beyond it. Indistinguishability in principle is defined as parity of structural affordances for arbitrarily deep indexical access, reconstruction, and consistency testing within a described domain. A structural no-go result follows directly. Descriptions that rely on selective resolution cannot simultaneously satisfy the demands of local resolvability and indistinguishability in principle. Either omitted structure must be supplied, abandoning selective resolution, or local resolvability must fail, rendering the description distinguishable in principle. That these are the only two outcomes follows from the structure of the incompatibility: any partial scope expansion either suffices to close the relevant consistency domain, constituting full expansion, or it does not, in which case distinguishability follows. No third outcome is available. This result amounts to a structural limit on whether a bounded simulation can withstand unlimited internal consistency testing: no selectively resolved description can be made indistinguishable from a globally complete one, regardless of the resources or ingenuity applied. The obstruction does not depend on assumptions about physical feasibility, probabilistic reasoning, or motivational considerations. The incompatibility identified here is the same incompatibility formalised in the Compression--Resolution Duality \cite{hitchcock2026crd}; the present paper arrives at it independently from the direction of simulation indistinguishability and applies it to that domain.