Stability as the Selection Principle of Reality - A Structural Bridge Between Quantum Configuration Space and Persistent Physical Reality

This paper proposes a structural principle that explains how physical reality emerges from quantum configuration space. While quantum mechanics accurately describes systems as superpositions of possible configurations, it does not by itself explain why only certain configurations persist as physical reality under interaction. We introduce stability as a necessary condition for persistence, derived from the requirement that physical systems must produce consistent relational outcomes under repeated interaction. Configurations that fail to satisfy this requirement cannot be empirically identified and therefore cannot constitute elements of physical reality. Within this framework, quantum states define structured configuration spaces, interaction imposes consistency constraints, and stability acts as a selection mechanism. Measurement is reinterpreted as stability-based selection rather than collapse or branching. A concrete analysis of a decoherence scenario demonstrates how incompatible correlation structures fail to persist. The framework distinguishes between state-level stability, governing the persistence of configurations, and sequence-level stability, governing coherence across change. While the present work focuses on physical persistence, this distinction provides a foundation for extending the same principle to identity and higher-level structures. This work does not modify the formalism of quantum mechanics, but provides a structural account of how probabilistic configuration spaces give rise to persistent physical reality.