Entropy-Action Equivalence: Emergent Spacetime and its Cross-Domain Validation

This paper establishes Entropy-Action Equivalence (EAE): entropy and action are the same physical quantity expressed in different units. That identity is not assumed. It emerges independently across ten unrelated frameworks spanning quantum theory, thermodynamics, gravity, and information theory… a level of consilience that demands explanation. From EAE, a compact set of theorems follows. Time, space, mass, temperature, and gravity emerge as measurement projections of a single irreversible counting process. Spacetime is therefore not fundamental; it is derived structure. The framework then does what syntheses rarely do: it makes blind, zero-parameter retrodictions that match real data. Gravitational matter-wave phase shifts, decades of microgravity protein crystallization results, and the thermal–gravitational relation confirmed by modern optical clocks all fall out quantitatively, without tuning. At this point the burden of proof flips. To reject the conclusion, one must explain why independent theories converge on the same entropy-action identity, and why its consequences reproduce experiment without adjustment. If you want to understand why spacetime is most likely not fundamental… this is the paper to read.