The Ultimate Relativity: A Four-Postulate Framework Unifying Spacetime Ontology, Quantum Measurement, and Relativistic Charge

We present four postulates that together constitute a self-consistent ontological framework for physics, which we call The Ultimate Relativity. The framework proposes: (I) that all physical entities - mass, energy, charge - are restructurings of space itself (the Space Postulate); (II) that every particle is created together with a superluminal shadow/wave counterpart carrying opposite energy, momentum, and angular momentum, separated from the observable particle by the perceptual boundary at speed c (the Pair Postulate); (III) that a particle's existence is discrete - it appears and disappears with a characteristic "motional frequency" that is the physical origin of time (the Time Postulate); and (IV) that any detection event involves the simultaneous meeting of the particle and its shadow at the detector (the Measurement Postulate). We show that these four postulates are not in conflict with established physics but rather provide a deeper ontological foundation for it: the Space Postulate corresponds to Wheeler's spacetime foam and emergent-spacetime programmes; the Pair Postulate identifies the shadow with the de Broglie-Bohm pilot wave and naturally produces Zitterbewegung; the Time Postulate recovers the de Broglie internal clock relation nu_0=m_0c^2/h, confirmed experimentally; and the Measurement Postulate provides a concrete physical mechanism for the Born rule without invoking wavefunction collapse. We further show that the Pair Postulate implies a velocity-dependent rest charge for the electron - the central postulate of Dan's reformulation of electromagnetism - as a direct consequence. The framework therefore unifies the relativistic charge reformulation, the cosmic expansion mechanism, and the neutron magnetic moment derivation under a single coherent set of first principles.