Constraint-Based Ontology

This paper develops a constraint-based framework for evaluating ontological candidates by integrating three independently motivated domains: physical structure, normativity, and practical-historical irreversibility. Rather than advancing a positive ontology, the argument proceeds by coordinated restriction, asking which kinds of models remain admissible once these domains are taken jointly as explananda. Two results structure the analysis. First, a closure result (PNS*) shows that identity- indexed normative reasons are not preserved under structurally invariant mappings without loss, even when these are enriched with causal-historical or modal resources — and that this failure is a failure of normative preservation, not merely of descriptive completeness: representing a history is not the same as being its bearer. Second, the space of admissible integrations is further constrained by the requirement that reasons remain mutually assessable in an invariant sense — assessable as genuinely agreeing, conflicting, or ordered in priority, independently of the mediating scheme of comparison — while purely structural preservation remains unavailable. As a corollary of the normativity constraint, the analysis identifies Axiological Dependence Reversal (ADR) — the structural condition in which an instrumental domain comes to determine the value of the end it was designed to serve — as a systemic form of normative closure relevant to high-mediation systems; this corollary is developed in a companion paper. Within this constrained model space, no stable configuration has been identified in which these conditions are jointly satisfied without either reintroducing structural equivalence or collapsing evaluability. The strong form of ARP does not enter as an independent assumption but as the unique stable resolution of its weaker formulation under the preservation constraints established by PNEN and PIR. This yields a restricted necessity claim: not that a specific ontology must be adopted, but that certain forms of reduction — particularly single-level reductive frameworks — systematically incur explanatory loss under the given constraints. The paper situates these results in relation to debates on non-separability in physics, structural realism, and the irreducibility of normativity, and proposes a comparative, non-totalizing method for assessing ontological viability. Within the constrained evaluative space, the argument develops a comparative preference for a unifying condition of the Logos type — not as a demonstrated conclusion but as the only currently identified candidate that satisfies all constraints without loss. This preference is explicitly conditional on accepting strong ARP and remains open to revision if a competing account can preserve the relevant explananda without constitutive historical indexation. The argument culminates in a typological evaluation of the Incarnation as the only currently identified instance satisfying the conditions of internal normative restoration; this final movement operates in the register of philosophical theology and fides quaerens intellectum — giving conceptual structure to what the believer already holds, not producing assent in one who does not.