The Ontology of Statistical Mechanics: Statistics of Constraint Transition Events in Causal Networks

What is statistical mechanics, constitutionally? Standard statistical mechanics defines itself as the grammar of ignorance --- the systematic treatment of uncertainty about microscopic states. EET statistical mechanics defines itself differently: it is the dual-layer discipline of constraint transition events. The Formal Layer (CLOSED-in-EET) derives the structural forms of the Second Law, Third Law, Fluctuation-Dissipation Theorem, and Causal Indifference Principle from the asymmetries of CND v4. 0 dynamics --- independent of any Observer's counting operations. The Numerical Layer (STANDARD) instances probability values, effective temperatures, entropy values, and ensemble constructions through the statistical compression of Observer registration records --- dependent on Observer counting operations, executable by instrument Observers without internal models. SM 3. 1 explicitly acknowledges that its own numerical outputs are CCN Observer cognitive products. This dual-layer architecture resolves the constitutional tension between SM's claim to universal applicability and its operational dependence on Observer registration data streams. The Formal Layer's theorems carry system-internal conditional necessity under EET's L1 constitutional presuppositions; they do not claim absolute truth (L0-compatible). The Numerical Layer's outputs carry model-internal objectivity anchored in Natural Causality --- probability values are long-term frequencies of registered constraint transition events, not ``objective tendencies'' independent of all observers. Version 3. 1 is a comprehensive constitutional upgrade from v3. 0 (v6. 0 alignment). The core innovations are: (i) explicit distinction between the Formal Layer (CLOSED, Observer-independent) and the Numerical Layer (STANDARD, Observer-dependent) ; (ii) full v6. 1 constitutional alignment (L0--L5+ layer renumbering, Barrier Asymmetry conditionalized, ``Constraint + Being'' correction, CD v3. 1 CND v4. 0 upgrade) ; (iii) integration of Observer v2. 4 (new core definition: detection registration) and Measurement v2. 1 (six-stage energy ledger, dark data boundary, five-channel noise decomposition) ; (iv) the No-Equilibrium Theorem established as CLOSED-in-EET --- a constraint network with N 1 can never reach classical statistical equilibrium, guaranteed by four independent mechanisms; (v) the Five-Channel Complete Constraint Second Law (CND v4. 0 III-C. 2, CLOSED-in-EET) adopted as the constitutional architecture for all non-equilibrium statistical mechanics in EET; (vi) the -generalized Fluctuation-Dissipation Theorem registered as WORKING HYPOTHESIS; (vii) the data completeness boundary established --- SM statistics apply only to registered events, with Transient-only events (dark data) lying outside SM's statistical scope; (viii) sixteen academic priority registrations across the major foundational controversies in statistical mechanics; and (ix) all v3. 0 constitutional content preserved with corrections and version updates applied. Constitutional Governance: Five-Channel Complete Constraint Second Law (CLOSED-in-EET). No-Equilibrium Theorem (CLOSED-in-EET). Five-path Third Law derivation (CLOSED-in-EET). C (t) constitutional identity (I₏₋₀ₒₓ₈₂, CLOSED-in-EET). = 1 equilibrium clarification (CLOSED-in-EET, triple citation: CND v4. 0 + Entropy v3. 3 + Inverse Entropy v3. 3). All contents carry system-internal conditional necessity under EET's L1 constitutional presuppositions and the L0 Sole Meta-Axiom (Absolute Truth is Unreachable). Keywords: Statistical mechanics; Constraint transition events; Dual-layer architecture (Formal Layer / Numerical Layer) ; Five-Channel Complete Constraint Second Law; No-Equilibrium Theorem; -generalized Fluctuation-Dissipation Theorem; C (t) statistical mechanics; Data completeness boundary; Dark data; Observer v2. 4 integration; Measurement v2. 1 integration; Non-equilibrium statistical mechanics; Energy-Efficiency Theory