The Born Rule from Torsion Density Measurement

The Born rule — P(outcome i) = |⟨i|ψ⟩|2 — is the only postulate of quantum mechanicswithout a derivation from deeper principles within the standard framework. Existingderivations (Gleason 1957, Zurek 2003, Deutsch 1999) recover the rule from assumptionsabout Hilbert space structure, symmetry, or decision theory, but none derive it from amechanical substrate. This paper derives the Born rule within the Cohesion UnifiedField Theory from two results already established in the series: (1) torsion density —the energy density of the recursion field — is quadratic in the recursion field amplitude,following from E = pr applied to a linear recursion field; and (2) a macroscopicmeasuring device responds to torsion density (energy deposited in each pointer stateconfiguration), not to field amplitude directly, because its structural time rate is slowrelative to the system’s recursion frequency and it averages over rapid field oscillations.The squared modulus in the Born rule is therefore not a postulate: it is a consequenceof wave energy being quadratic in amplitude, applied to the moment of structural timesynchronisation between system and device. The derivation is complete at the level ofwave mechanics; the remaining open problem is an explicit derivation of the recursionfield wave equation from the Cohesion UFT field equations, rather than an appeal tothe universal quadratic property of wave energy. This paper closes the primary openproblem of the quantum measurement paper and the quantum field paper of this series.