Chapter 4: SelfDesc-of-SelfDesc: The E₃ Structure

The E₃ enrichment layer is formalized. At E₂, a living system carries and decodes its own code (SelfDesc). At E₃, a system models the fact that it carries and decodes its own code (SelfDesc-of-SelfDesc). The MetaDecode operator takes the evaluator itself as input. The E₃ Non-Emptiness Theorem is proved constructively via the BH basin law-code as canonical carrier, establishing that the metaphysics layer is inhabited.