= Solution
In the <many-worlds interpretation>, the universal state evolves unitarily. A measurement transforms $(\alpha|0\rangle+\beta|1\rangle)|M_*\rangle$ into $\alpha|0,M_0\rangle+\beta|1,M_1\rangle$. <Environmental decoherence> suppresses interference between macroscopically distinct records, so each branch contains a consistent observer record of one outcome. There is no stochastic selection of a unique global result in that dynamics. Thus fundamental indeterministic collapse is not recovered; it is deliberately absent.
The appearance of indeterminism can nevertheless be described branch-relatively. Before examining a record, an observer lacks information about which recorded result will be encountered in a future branch-relative history. After measurement, each descendant has one stable record and experiences a definite result. This is more than saying that a classical observer does not know a predetermined hidden bit, because the global state includes multiple continuing record structures rather than one unknown selected trajectory.
The hard question is why uncertainty or rational expectation should follow the <Born rule>[Born weights] $|\alpha|^2,|\beta|^2$. <Decoherence> explains approximately autonomous records and a preferred coarse-grained basis, but does not by itself turn all branch counts into a unique measure. Literal counting is ill-defined because branches do not have a uniquely fixed number. Decision-theoretic, <symmetry> or typicality arguments try to justify squared-amplitude weights and their role in observed frequencies, but their auxiliary assumptions must be assessed rather than silently called consequences of <unitary> dynamics alone.
The interpretation can therefore account structurally for the appearance of definite unpredictable outcomes without adding dynamical randomness. Whether that completely accounts for <probability> depends on a successful connection from branch weights to expectation and confirmation. Its strength is a uniform dynamical law for system and observer; its cost is an ontology and <probability> account that go beyond the experience of one apparently unique outcome.<Relative State Formulation of Quantum Mechanics by Hugh Everett III>[1957, measurement correlations, relative states and statistical predictions]{ref}
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