We propose a reinterpretation of general relativity and quantum field theory in which the quantum vacuum has a finite response capacity at the Planck scale. We call this the Planck Vacuum Response Medium (PVRM): a structured vacuum whose response is encoded in the gravitational coupling constant κ. Using relativistic time dilation, we define an operational response parameter γ(x) from clock rates in gravitational fields and at relativistic velocities. In the weak-field and non-relativistic limits, spatial gradients of γ(x) recover gravitational acceleration, while temporal variation reproduces inertial resistance, without changing the standard mathematics of relativity. In this view, the equality of inertial and gravitational mass is not an extra postulate; it follows from the same rest mass m0 entering through the common response factor (γ − 1). We also write the Einstein coupling as κ = 8πlpltpl/ℏ and interpret it as the response capacity of a single Planck-scale vacuum cell per quantum of action. Quantum gravity, then, corresponds to the regime where the discrete structure of vacuum response matters, while classical general relativity is the continuum limit.
Roopkom et al. (2026) studied this question.