Second-Order Stability Epistemology (SOSE) introduces a systemic analytical framework designed to investigate structural stability in complex socio-technical systems. The work addresses the Stability Paradox — the phenomenon in which institutions, infrastructures, and governance systems maintain operational functionality while internally accumulating epistemic and structural erosion. SOSE proposes that long-term stability cannot be sufficiently explained through performance efficiency or predictive control models alone. Instead, stability is conceptualized as a validation-dependent process requiring continuous alignment between internal system representations and external environmental complexity. The framework integrates three core analytical components: • The VUS Metric (Validation–Energy–Stability), modeling systemic stability as a function of validation resource allocation, epistemic entropy dynamics, and temporal synchronization effects. • The MOERS Framework (Multi-Order Epistemic Reflection Schema), providing a reflexive diagnostic model across hierarchical decision reflection layers: operational execution, procedural validation, strategic orientation, and existential responsibility integration. • The Integrative Stabilization Model (ISM), incorporating socio-cognitive constraints, anthropological decision limitations, and institutional validation dependencies into stability modeling. SOSE is explicitly grounded in the ontological boundary framework established by Second-Order Coherence Science (SOCS), which defines the theoretical and methodological limiting conditions of epistemic validation processes. Together, SOCS and SOSE form a layered research architecture connecting boundary epistemology with operational stability diagnostics. This research contributes to interdisciplinary fields including systems theory, epistemology, governance science, financial system stability research, institutional resilience studies, and emerging AI governance frameworks. The architecture does not propose predictive technocratic control but instead focuses on early detection of systemic fragility through validation-based stability diagnostics. SOSE is proposed as an open interdisciplinary research program intended to support future investigations into epistemic stability, human–AI co-evolution, decision responsibility preservation, and long-term institutional resilience under increasing systemic complexity.