Recent approaches to spacetime completeness, quantum unitarity, and maximal extension frequently invoke the necessity of mirror structures: formally paired sectors required to close dynamical descriptions, preserve information bookkeeping, or maintain mathematical consistency. In several modern interpretations, these mirrors are promoted to physical entities and interpreted as reversed arrows of time, dual temporal branches, or time-inverted universes. This paper argues that such interpretations exceed what formal completeness actually requires. While mirror structures are indeed necessary at the level of description, physical time reversal is neither required nor compatible with empirical reality. Observed irreversibility, memory formation, entropy growth, and net accumulation of structure cannot arise from exact temporal symmetry or from two perfectly mirrored time directions. The central claim is that mirrors should be understood as complementary dynamical sectors operating within a single, monotonic time parameter. These sectors represent paired but non-identical processes such as ordering versus dissipation, coherence buildup versus coherence relaxation, and memory retention versus memory degradation. A net dynamical driver emerges from their imbalance, generating directionality without invoking backward time or multiple temporal ontologies. The paper develops a strict separation between formal completeness and physical ontology. Formal mirrors serve a bookkeeping and closure function; they do not duplicate reality or reverse causation. Asymmetry between mirrored sectors is shown to be a structural necessity rather than an interpretive choice, and even a minimal asymmetry is sufficient to generate history, memory, and irreversible evolution. No specific cosmological model, quantum interpretation, or physical parameterization is assumed. The argument is structural and discipline-focused, establishing mirrored dynamics without time reversal as both sufficient and necessary for a physically realistic single-time ontology.
Ivo Gerlach Angela Noel Cerfontaine (Sat,) studied this question.