Abstract

This document formulates the ontological and epistemological foundations of the Unified Information-Density Theory (UIDT). Rather than postulating spacetime as a primordial arena, UIDT investigates the hypothesis that a single real scalar field, the vacuum information density S(x), may serve as a fundamental geometric degree of freedom. The present edition is deliberately conservative: it is the product of a line-by-line honesty audit that downgraded several earlier claims and that treats the framework as a falsification-first research programme rather than a completed theory. The framework rests upon four explicit axioms and addresses four areas: (I) a quantum field-theoretic foundation in which the pure-SU(3) Yang-Mills spectral gap Delta = 1.710 +/- 0.015 GeV [B] functions as a necessary stress test of internal consistency rather than as a sufficient foundation, and in which the gap value is lattice-compatible under an explicitly recorded evidence-class reclassification (section 1.2); (II) cosmological calibration to DESI, JWST, and ACT data, capped at [C] and never presented as a resolution of the H0 or S8 tensions; (III) laboratory-relevant predictions, including a candidate scalar resonance at mS = 1.705 +/- 0.015 GeV [D] and a Casimir-scale anomaly at lambda = 0.66 nm [D]; and (IV) a structural mapping between the vacuum scalar and effective refractive-index profiles, retained as an interpretive analogy. The calibrated invariant gamma = 16.339 is classified throughout as [A-] (calibrated, never derived from renormalisation-group first principles); any future derivation must satisfy an explicit anti-target-leakage criterion. The naive scalar-gradient route to non-trivial gauge curvature, A = dS => F = dA = d2S = 0, is recorded as a clean [A] negative result. The central open problem, the GSM-Origin Gap, is preserved as unsolved. Every quantitative claim carries an explicit evidence classification (A through E), every prediction is accompanied by a falsification criterion, every known limitation (L1-L12) is disclosed, and speculative observer-phenomenology material is retained strictly as bounded Category [E] research-programme content within an interpretive stratum. The ontological position is a form of dynamic Ontic Structural Realism in which sufficiently constrained mathematical structure is taken to constitute, rather than merely describe, physical reality, subject always to the demarcation that interpretation never substitutes for empirical or formal closure.