This monograph-length investigation examines the cosmological implications forced by the empirical results established in Volume I of the Causal Response Framework. Using the same regime-based, falsification-driven methodology, the work asks not which cosmological models are preferred, but which classes of cosmological behavior remain admissible once instantaneous gravitational inference is excluded.

Rather than proposing a forward cosmology, the analysis proceeds by systematic elimination across four stages. A sequence of preregistered adjudication criteria and empirical probes tests whether any admissible cosmological response can remain consistent with observed temporal ordering, spatial coherence, environmental modulation, large-scale structure persistence, and expansion history constraints. The surviving constraint structure restricts admissible behavior to a narrow class of environment-conditioned, history-dependent cosmologies, designated the Aging Spacetime Medium. A further sequence of classical exhaustion tests — probing redshift-dependent relaxation, kinematic-regime discrimination, conditional coherence, and spatial incoherence — establishes that no classical realization of the surviving structure remains admissible. The volume concludes by identifying objective, observer-independent state reduction as the surviving mechanism class through logical elimination of alternatives, while explicitly acknowledging the gap between eliminative inference and constructive derivation.