The empirical record across physics converges abductively with the structural claim, without on its own establishing it. Noether's -(Noether, Emmy, 1918) theorem links each continuous symmetry of a theory's action to a corresponding conserved current within that theory; it formalizes the relation between symmetry and conservation, but the modal necessity of conservation across all possible mediums is not what Noether proves. What Noether supplies is the form physics takes when the structural invariances of the medium are read through a least-action principle (the variational principle by which a system's actual trajectory is the one that extremizes a functional of its history called the action, the framework standard physics uses to derive equations of motion): under that reading, every standing symmetry yields a conserved current. The unitarity of quantum evolution (the mathematical property that quantum-state evolution preserves total probability and, with it, the in-principle recoverability of the initial state from the final state) preserves information across closed-system transitions within standard quantum mechanics; whether information is preserved in the most extreme cases, most prominently the black-hole evaporation problem (Hawking -(Hawking, S. W., 1976); Page -(Page, D. N., 1993); recent island-formula work, Penington -(Penington, G., 2020) and Almheiri et al. -(Almheiri, A., T. Hartman, J. Maldacena, E. Shaghoulian, and A. Tajdini, 2020)), remains an active question, with the contemporary consensus moving toward preservation but the mechanism still under construction. Relativistic correspondence shows that local frames disagree about how the conserved stock is partitioned among mass, energy, and momentum, but not that the stock itself persists: the partition is frame-relative; the conservation is not. General relativity sharpens this rather than threatening it: on a cosmological scale there is no global time-translation symmetry, so there is no conserved global energy: expansion redshifts photons and dark energy does work with no compensating store (Wald -(Robert M. Wald, 1984); Carroll -(Sean M. Carroll, 2004); the absence of a timelike Killing vector in a generic expanding FRW spacetime leaves global energy undefined), which is exactly the contingent half of the split ([§7.4](<7.4 Substance.md>)) at work. What persists is not a fixed global quantity but the structural constraint that no causal relatum passes into or out of absolute nothingness; which quantities are conserved, and whether globally, depends on the symmetries a given spacetime has. The quantum vacuum, finally, is not nothing. It is Φ at minimum energy: a structured field whose fluctuations occur inside what was supposed to be nothing at all. What these results share is not a single mechanism but a single direction of fit, and the modal argument's conclusion is the convergence target each is moving toward from its own side.


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← [7.4.3 What is Predicted](<7.4.3 What is Predicted.md>) | [7.4.5 What is Concluded](<7.4.5 What is Concluded.md>) →
