Structural Differentiation Time (SDT) v1.4: A Minimal, Falsifiable, and Directly Testable Framework for the Irreversible Origin of Time

This work presents Structural Differentiation Time (SDT) v1.4, a minimal, falsifiable, and directly testable framework in which time is not treated as a background parameter, but as an emergent observable generated by irreversible structural differentiation. The central result is a conceptual inversion:irreversibility is not a consequence of time, but its physical origin. Unlike conventional interpretations that attribute the arrow of time to thermodynamics, SDT proposes that irreversibility arises intrinsically from structural dynamics. The framework introduces no new physical entities and does not modify existing fundamental laws. Instead, it provides a structural reinterpretation that yields directly measurable and experimentally testable predictions. A single decisive observational criterion is defined:a nonzero second derivative of structural time distinguishes irreversible structural time from reversible dynamics. This establishes time as a testable physical observable and identifies structural irreversibility as its fundamental basis. The work is supported by a complete set of reproducible figures and a minimal implementation, ensuring transparency and reproducibility.