Operational Cosmology from Finite Distinguishability: Expansion as Growth of Configuration Capacity

This work develops an operational cosmological framework in which spacetime geometry and cosmic expansion emerge from finite, causally constrained distinguishability. Physical states are defined operationally through finite-resolution measurements rather than assumed as elements of a pre-existing geometric manifold. The configuration capacity, defined via packing numbers, quantifies the number of macroscopically distinguishable configurations. Cosmological expansion is reinterpreted as growth of this capacity, leading naturally to FLRW geometry, an effective inflationary regime, and late-time acceleration without introducing fundamental scalar fields. The framework is consistent with holographic entropy bounds and treats geometry as an emergent relational structure arising from physically allowed operations of distinguishability. It provides a conceptually grounded alternative perspective on spacetime emergence and cosmological dynamics.