Indistinguishable in Principle, Distinguishable in Practice: Einstein's Equivalence Principle Reassessed, and the Predictions of Relativity Recovered from Quantum-Geometry Dynamics

This manuscript critically examines the foundational assumption of the Einstein Equivalence Principle (EEP), proposing a structural and measurable distinction between gravitational and non-gravitational accelerations. While the EEP asserts the strict local indistinguishability of a uniform gravitational field and a uniformly accelerated reference frame, this paper introduces a "two-mass discriminator" protocol capable of breaking this theoretical degeneracy. By analyzing the kinematics of a dual-mass system within a sealed, local environment (analogous to the classic Einstein elevator), the framework demonstrates that propulsive (non-gravitational) acceleration necessarily induces a measurable, mass-dependent kinematic drift between two distinct test masses. Conversely, true gravitational acceleration acts uniformly on the inherent properties of the system, producing no such internal drift. This structural asymmetry implies that a local observer can, in practice, mathematically and physically determine the source of their frame's acceleration without requiring external reference points. This paper provides the foundational arguments and mathematical proofs for this discriminator protocol, offering a new perspective on the limits of equivalence and the fundamental nature of mass and gravity within the Minimal Physically Derivable Theories (MPDT) / Quantum-Geometry Dynamics (QGD) framework. Version Notes (Version 2): This updated manuscript includes the complete mathematical derivation of the two-mass discriminator experiment (detailed in Section 2.3), providing the rigorous mechanical and kinematic grounding necessary to support the proposed protocol.