The Empirical Distinguishability of Quantum Interpretations

Quantum interpretations differ in ontology, dynamics, and the meaning of quantum states, but these differences become empirical alternatives only when they yield different records for a com-mon experiment. Two worked comparisons establish where discrimination succeeds and fails. In a trapped-particle arrival-time model, paired spin ensembles have identical density operators but detector-free first-entry laws separated by an exactly calculable total-variation distance. A common quantum instrument nevertheless gives them identical record laws, with a sharp obstruction to re-producing both free-arrival distributions. A second comparison places universal unitary evolution and genuine collapse in the same coherent-memory experiment. An echo removes constant detuning but leaves ordinary Markov dephasing exactly confounded with collapse when their total rates co-incide. Independent noise and readout bounds yield a discrimination gap, an optimal observation time for equal trial cost, and a finite-sample guarantee. Comparisons involving GRW ontologies, relational quantum mechanics, and QBism clarify the roles of record formation and conditioning. Recent nanoparticle-interference and spontaneous-radiation experiments constrain specified collapse dynamics without uniquely favoring an ontology. A Bayesian analysis separates these constraints from posterior comparisons and from theoretical preferences based on scope, economy, and definite out-comes. It identifies the conditional case for Everett alongside the relevant Bohmian counterpoints. The resulting assessment permits unequal empirical support without claiming either universal equivalence or an experimentally established ranking of the surviving interpretations.