Redundant Environmental Recording as the Criterion for Classical Reality

Decoherence suppresses quantum interference but does not, by itself, determine when outcomes become classical facts. We propose a quantitative criterion for classical objectivity based on two conditions: (i) outcome states must exceed a minimal operational distinguishability threshold, and (ii) information about the outcome must be redundantly encoded across multiple independent environmental fragments. Using a spin–environment toy model, we show that the time at which decoherence is effectively complete can precede the time at which this redundancy threshold is crossed. This leads to a temporal gap between “decohered” and “classically real” regimes, and to experimentally testable predictions: two systems with identical reduced dynamics for the system can exhibit different classicality onset times depending solely on the fragmentation structure of their environments. The framework preserves unitary dynamics and sharpens the conceptual core of quantum Darwinism into a finite, falsifiable criterion for when quantum events become classical facts.