Meaning–Inertia: An Ontological Substrate Beneath Inertia, Gravitation, and Spacetime

Meaning–Inertia: An Ontological Substrate Beneath Inertia, Gravitation, and Spacetime proposes a minimal constitutional ontology beneath established physical formalisms. Rather than introducing new forces, fields, or dynamics, the paper identifies a candidate substrate - Meaning–Inertia (M-I) - that governs how physical systems participate in the emergent spacetime projection. Within this framework, inertia and gravitation are not primitive properties or interactions, but manifestations of a state-dependent participation scalar constrained by lawful invariants. Spacetime geometry is treated as emergent rather than fundamental, with de Sitter–like structure reinterpreted as a default projection regime under minimal binding constraint rather than as the gravitation of vacuum energy. The paper explicitly separates ontology from mechanism. It proposes no experimental apparatus and no control scheme. Instead, it articulates the constitutional invariants any such substrate must obey (conservation, causality, irreversibility, thermodynamic honesty, and refusal thresholds) and enumerates empirical null tests already accessible to existing metrology. Meaning–Inertia is presented as a falsifiable ontological hypothesis: neither empirically confirmed nor insulated from constraint. Its value lies in resolving long-standing conceptual tensions (the origin of inertia, the equivalence of inertial and gravitational mass, vacuum energy pathologies) while preserving all established predictive frameworks at the projection level.