Ether was not refuted as an ontological intuition; it was refuted as a mechanical model. PSOC4(3) recovers the deeper ether question by identifying ether as phase-spatial closure: not a medium in space, but the closure condition through which spatiality, phase, propagation, and lawful relation become possible. The classical ether was rejected because it was conceived as a mechanical substance inside space: a luminiferous medium through which light waves were presumed to propagate. Relativity correctly dissolved this model by replacing the need for a material medium with invariant spacetime geometry. Yet the failure of mechanical ether did not eliminate the deeper intuition that propagation, orientation, phase-relation, and lawful continuity require an underlying coherence condition. This paper argues that spacetime did not destroy ether but geometrized it. Quantum field theory then further transformed the ether question into the language of structured vacuum behavior. PSOC4(3) completes this historical sequence by recovering ether not as a medium, field-stuff, or preferred frame, but as phase-spatial closure: the fourfold architecture through which spatiality, phase, propagation, and lawful relation are disclosed. Keywords: ether, PSOC4(3), phase-spatial closure, spacetime, quantum vacuum, closure ontology, spatiality, propagation What this paper does and does not claim This paper does not claim the return of a classical luminiferous ether, a preferred frame, a mechanical fluid, or a detectable medium inside space. It claims that the deeper intuition behind ether was never fully resolved by spacetime geometry and can be reformulated as phase-spatial closure through PSOC4(3). The aim is therefore not anti-relativistic. The aim is post-relativistic: to distinguish spacetime as a powerful representation from closure as the deeper condition of disclosure.