The equivalence principle is the conceptual foundation of relativistic gravity,asserting the universality of free fall and the local indistinguishability ofgravitational and inertial motion. In this work we demonstrate that theequivalence principle follows directly from the Scalar Temporal Field Ontology(STFO), in which time is represented as a physical scalar field τ(xμ)governing physical evolution. We show that the allowed covariant couplings of matter to the temporal fieldimply universal interaction through the scalar invariantX = −gμν∂μτ∂ντ. Consequently the motion of test bodies depends only ongradients of temporal flow and not on internal properties of matter. In theweak-field regime this leads to the acceleration law a = −c²∇N, whereN = dτ/dt is the local temporal flow rate. Since this equation is independent of composition, universal free fall followsnecessarily. The smoothness of the temporal field further guarantees theexistence of local inertial frames in which gravitational effects vanish tofirst order, establishing the Einstein equivalence principle. The equivalence principle therefore emerges as a structural consequence ofthe universal scalar temporal field rather than as an independent postulate.
Cale Scott Howe (Sun,) studied this question.