The Non-Emulability of Execution (Agentic Necessity) Paper 19 (T2) of the NEMS Suite

A common paradigm in theoretical physics is the view of reality as a static lookup-table or a pre-computable simulation. In this paper, we prove that in a universe satisfying Perfect Self-Containment (PSC) with sufficient computational richness to host arithmetic self-reference (diagonal capability), these static views are logically forbidden. Building on the Stronger No-Emulation theorem (Paper 16), we introduce an Instance Encoding premise mapping abstract codes to universe states. We then prove the Theorem of Execution Necessity: no static algorithm can perfectly emulate the universe's internal adjudication while remaining total-effective on the diagonal instances. If such an emulation existed, it would induce a computable decider for record-truth, violating the diagonal barrier. Consequently, the universe cannot be a static lookup table; it must be actively "run" from within. Internal adjudicators (agents) are not biological accidents, but the necessary execution engine of physical reality. All definitions and theorems are formalized and machine-checked in Lean 4. Trust boundary. "Agents" denotes adjudicating subsystems in the formal sense (Paper 17 narrative compatible); the forcing lemma is nems-lean once instance encoding and diagonal hypotheses are as formalized. See .