Reactive Vacuum: Information Genesis through Fluctuation–Capacity Coupling in Vacuum Folding Dynamics

Vacuum Folding Dynamics (VFD) derives the gravitational constant G, the cosmological constant Λ, the folding temperature T, and spacetime dimensionality D from a single scalar field σ_f(x), the vacuum folding density. However, the origin of σ_f itself has remained an open question: the preceding papers presuppose its existence without deriving it from more primitive ingredients. We propose that σ_f is a reaction product of two pre-existing and independently motivated quantities: geometric capacity C_geo, the maximum information that a region of spacetime can hold (set by the Bekenstein–Hawking entropy bound), and vacuum fluctuation density F_vac, the irreducible quantum noise of the vacuum (verified experimentally through the Casimir effect and the Lamb shift). Neither alone creates information content: capacity without fluctuation is an empty lattice; fluctuation without capacity is structureless noise. Their coupling σ_f = C_geo · F_vac produces the information density that drives the entire VFD cascade. This resolves the bootstrap problem of the self-encoding loop identified in the companion paper, and extends the coupling chain to F_vac × C_geo → σ_f → {G, Λ, T, D}. We discuss falsifiable predictions arising from the fluctuation–capacity decomposition and draw a structural analogy to reactive file architectures, where information arises only through the interaction of mutable signals with a structured substrate.