Electromagnetic Wave Propagation in Expanding Spacetime: A Systems-Based Interpretation via Universal Laws of Nature

This paper presents a systems-theoretic interpretation of electromagnetic wave propagation in expanding spacetime, grounded in four Universal Laws of Nature: (I) Cause-Effect and System Integrity, (II) Universal Balance, (III) Feedback Mechanisms, and (IV) Interconnection. By mapping these principles onto Maxwell's equations and the Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological framework, photon behavior in an expanding universe is reinterpreted as a self-regulating adaptive process. A formal operator correspondence is proposed between each Universal Law and a quantitative physical relationship, including energy balance, geodesic feedback, and cosmological redshift. The framework does not replace standard physics but provides a unifying descriptive language that bridges physical law and general systems theory, with potential applicability to biological and cognitive domains.