by Stephen W. Porges

A recent critique advanced by Grossman et al. (2026, this issue) argues that Polyvagal Theory is scientifically untenable, asserting that its core claims regarding autonomic organization, respiratory sinus arrhythmia (RSA), and evolutionary framing are inconsistent with established neurophysiology. The present paper evaluates these assertions not by disputing individual claims in isolation, but by examining whether the critique engages Polyvagal Theory as it is articulated in the peer-reviewed literature and whether it meets the epistemic standards required for scientific refutation.
Rather than responding sequentially to individual objections, the analysis clarifies the theory’s conceptual foundations, scope, and explicit conditions of falsifiability as a systems-level, pathway-specific framework of autonomic state regulation. It demonstrates that the critique repeatedly evaluates a reconstructed proxy of the theory shaped by persistent category errors, including conflation of neuroanatomy with neurophysiology, reduction of theory to measurement, and substitution of phylogenetic continuity for functional organization. These structural misrepresentations propagate across methodological, neurophysiological, evolutionary, and developmental domains, precluding meaningful empirical adjudication.
Across these domains, the paper shows that disagreements concerning RSA metrics, comparative anatomy, or evolutionary framing do not engage the theory’s specified mechanisms or demonstrate conditions under which its predictions would fail. Where disagreement exists, it reflects differences in measurement preference, level of analysis, or theoretical framing rather than evidence against the theory’s organizing principles. An appendix presents a historical audit showing that several central claims reiterated in the critique were identified in the literature nearly two decades earlier as mischaracterizations of Polyvagal Theory. Their continued repetition without substantive modification reflects a persistent failure of representational uptake rather than unresolved empirical controversy.
It is concluded that the charge of scientific untenability does not apply to Polyvagal Theory as formulated, but instead reflects a critique that fails to engage the theory on its own terms. Productive scientific discourse requires representational fidelity, appropriate alignment of levels of analysis, and responsiveness to theoretical and empirical clarification ‒ criteria essential to theory evaluation but not met in the critique under review.

Key words: polyvagal theory, autonomic nervous system, vagal regulation, brainstem autonomic circuits, respiratory sinus arrhythmia, autonomic state regulation, social engagement system, developmental neurophysiology, evolutionary neurobiology, systems neuroscience, autonomic biomarkers