The Absolute Admissibility Boundary: Why "Nothing" Cannot Be Computed

Is it possible to evaluate existence, structure, or admissibility when all physical, logical, causal, informational, and temporal primitives are removed? While “nothingness” is frequently discussed across physics, computation theory, and philosophy, such discussions are almost always conceptual rather than operational. In this work, we present a constraint-based computational investigation designed to probe the deepest possible limit of evaluability itself. Using a global, model-agnostic simulation framework, we explicitly forbid all known primitives required for simulation, inference, and classification—including physical laws, spacetime, quantum formalisms, causality, information flow, logic, computation models, observers, and time—while allowing no fallback assumptions or corrective heuristics. The simulation executes successfully without numerical failure or implicit assumption injection. However, no coherent evolution, admissible structure, or evaluable outcome space emerges. Instead, the system converges to a formally undefined regime in which admissibility itself cannot be evaluated without reintroducing forbidden primitives. We identify this regime as an absolute admissibility boundary: a sharp separation between computable structure and non-definable domains. The results do not propose new physics or metaphysical claims about existence. Rather, they provide an operational demonstration that absolute absence is not a computable object, and that minimal structural constraints—specifically causality and information flow—are prerequisites for evaluation itself. This work reframes foundational debates by shifting attention from what exists to what must be assumed for questions to be meaningfully asked.