Universal Integrity Principle (PIU-Ψ): A Single-Substrate Foundations Program — Version 4.8

This is the manuscript of a foundations program that explores a radical and precise hypothesis: that gravity, light, particles, space, time and the dark sectors are configurations of a single physical substrate — "el Pleno" — described by one field Ψ = S·e^(iθ) and six axioms (A1–A6) condensed into a single Lagrangian (F1). From two substantive properties of the medium (ρ_P, ℓ_P) and its causal structure (c), the program recovers the gravitational constant G and the reduced Planck constant ħ with agreement better than 0.1% without fitting; derives the Heisenberg uncertainty relation with its exact ħ/2 floor; makes gravity emerge (Newtonian mechanics in the weak-field limit and the structure of Einstein's equations by induced action, with the geodesic and the Schwarzschild metric as a geometric reading of the medium); recovers the structure of the Dirac equation; derives the Maxwell equations and the non-abelian Yang-Mills structure from phase circulation over a diamond lattice; obtains the cosmological ratios Ω_MO/Ω_M = √3·π (0.86σ from Planck) and Ω_EO = f_c ≈ 0.6869 (0.30σ) with zero free parameters; and reads Special Relativity as the rheology of a dilatant fluid. General Relativity and Quantum Mechanics cease to read as two theories awaiting reconciliation: they emerge as effective readings of the same medium, an integration already operative at the quantitative level. The program matches ΛCDM statistically using the same degrees of freedom, but with DERIVED parameters rather than fitted ones, and it adds unique falsifiable predictions testable with instruments such as LISA, Fermi-LAT and CMB-S4. Every result carries its algebra and an explicit epistemic classification (derived, strong logical deduction, calibrated, hypothesis), and every open thread is declared. The invitation is to verify it. This is Version 4.8 of the manuscript (351 pages), the first full English-language edition.