Probability as τ-Projection: Randomness, Necessity, Distribution, and the Boundary of Induction in a Logic of Integrability

Within the τ-Logic program, this paper reconstructs scalar probability as a licensed projection/readout from a declared normalized τ phase regime. It uses the Layer-0 τ-identity reference and the zero/projection-nullity analysis as public continuity references, without treating either work as a hidden premise for the probability theorems. Its formal core is conservative: once τ-identity is represented in a declared native normalized compact phase domain, S¹ ≅ U(1) supplies normalized Haar phase measure, measurable τ-readout maps induce pushforward laws, and probability laws on standard Borel spaces are representable as such pushforwards. The paper preserves Kolmogorov probability as the ordinary measure-theoretic readout layer; it does not claim that named distributions are uniquely forced from bare τ. Instead, τ-Probability supplies structural provenance only under declared phase-completion, compact phase-domain, Haar-measure, measurable-readout, and local-licensing assumptions, so probability values remain late scalar readouts whose licensing structure includes a source space, σ-algebra, measure, readout/projection map, and local constraint regime. Universal representability is global; distributional necessity is regime-specific. Probability-zero is treated as measure-nullity under a declared regime, not as impossibility, event absence, or ontological nullity. The Borel–Kolmogorov boundary confirms this discipline: E = 0, C = 0, and E = C are phase-coordinate null-readout conditions, not intrinsic conditional events or carrier-nullities, and exact conditioning on them is licensed only by a declared conditioning/readout regime.