Breaking the Stasis in the Polyvagal Controversy: Two Category Errors, a Missing Variable, and a Measured Boundary

For twenty years, the dispute over Polyvagal Theory (PVT) has turned on whether the profound bradycardia attributed to dorsal vagal shutdown occurs in ordinary human freezing and dissociation. The 2026 Grossman–Porges exchange sharpened that dispute without resolving it. We argue that it cannot be resolved as framed, because neither position specifies the variable that would adjudicate it: the pervading neurochemistry under which a recruited circuit operates. PVT made the required observation once, in 2001, when it paired oxytocin-conditioned calm immobilization with vasopressin-conditioned immobilized fear at identical dorsal vagal anatomy. The observation was never generalized, because the neurochemical model PVT inherits retains a two-pole structure in which the endogenous opioids have no position. We propose a three-variable model in which neuroception selects the circuitry recruited and modulatory chemistry determines what that circuitry produces. As a falsifiable hypothesis, severable from the model, we propose that the cardiac and respiratory signature of life-threat immobilization requires endogenous µ-opioid activity, and that naloxone administered during confirmed shutdown should reverse bradycardia and restore respiration on the timescale of the drug’s onset. Independently of the model, electron-microscopic fiber counts of human vagal tissue show that the supradiaphragmatic/subdiaphragmatic discontinuity is confined to the myelinated population, placing that partition on direct measurement rather than comparative inference. Because escapability rather than phylogenetic age selects the state, PVT’s clinical claims do not depend on its evolutionary reconstruction. The observations of both parties describe physiologically distinct conditions, and the model, drawn from Autonomics, converts a twenty-year standoff into experimentally decidable predictions.