Mirror Architecture of the Paton System: Compression and Expansion Around the Tier‑4 Datum

The Paton System describes a structural architecture in which system existence depends on admissibility conditions prior to dynamics or optimisation. Within this architecture the Tier-4 datum represents the observational interface where systems become visible and interpretable through human knowledge frameworks. This paper formalises the mirror architecture implied by the Paton System. Structural possibility exists at both extremes of the framework. At one extreme lies pre-structural possibility, represented by Tier-0 availability, while the opposite extreme corresponds to large-scale system horizons represented by the Boundary Horizon. Human knowledge operates between these limits. Structural information compresses toward the Tier-4 observational datum until it becomes measurable and interpretable. From this position scientific knowledge expands outward into domain-specific interpretations such as physics, biology, engineering, and artificial intelligence. The resulting architecture forms a mirror structure: ∞ → structural compression → Tier-4 datum → interpretive expansion → ∞ The Tier-4 interface therefore acts as the translation layer between infinite structural possibility and finite human knowledge.