The Born Rule as Constraint Measure: Dissolving the Probability Problem in Quantum Mechanics

The Born rulethe prescription that measurement probabilities equal the squared mod- ulus of wave function amplitudeshas resisted satisfactory explanation for nearly a century. We argue that this diculty stems from a hidden assumption: that probability names a causal concept requiring causal explanation. Drawing on causal eliminativism, we reinterpret the Born rule not as describing the probabilistic eects of measurement, but as specifying a measure on the space of constraint-satisfying congurations. From this perspective, Glea- son's theorem does not derive probability from quantum mechanics; rather, it identies |ψ|2 as the unique coherent measure compatible with Hilbert space geometry. The question Why does measurement cause probabilistic outcomes? dissolves: there is no causation, hence no probabilistic causation, hence no puzzle. What remains is a geometric fact about constraint structure