Born Internal & Complete Semantics Implies Perfect Self-Containment: { The Reverse Direction—From Quantum Probability to Closure}

We prove the reverse direction of the PSC–Born fixed-point architecture: if quantum probability (Born rule) provides the internal, complete semantics for macroscopic records, then external model selection is impossible and the theory must satisfy Perfect Self-Containment (PSC). Formally, we define Born Internal & Complete Semantics (BICS) as a semantic-architecture condition stating that record probabilities are given by the Born rule via an internal quantum state, are context-independent (noncontextual), and are semantically complete (no external completion bits). We prove: BICS ⇒ NEMS (No External Model Selection), and under existing closure reductions (Externality Reduction + semantic visibility), BICS ⇒ PSC bundle / Full PSC. Within the explicitly defined universe class and under the BICS semantic-architecture condition, PSC and Born-as-internal-complete-record-semantics are equivalent. Combined with the forward direction (Papers 8, 13: PSC ⇒ Born semantics), this establishes a fixed-point equivalence: within an explicitly defined universe class, PSC and Born-as-internal-complete-record-semantics are architecturally equivalent. This overview presents the core NEMS theorem engine and selected applications; stronger domain-specific derivation and ontological synthesis claims belong to separate release surfaces with their own premise bundles and formal artifacts. The core theorem (BICS ⇒ NEMS) is fully machine-checked in Lean 4 with zero custom axioms and zero sorry.