How inclusive is the brainstem rule? Partiality beyond consensus

In his 2024 book, Jonathan Birch builds a precautionary framework for the borderlines of sentience, one that is meant to guide both theoretical reflection and practical action. One of the book’s great merits is its bottom-up approach, which presents itself as theoretically neutral regarding the (neuro-)physiological criteria required for sentience. Yet the singular place granted to midbrain-centric views (e.g., Merker, 2007; Panksepp, 2011; Solms, 2021) and to what Birch calls the “brainstem rule” (Chapter 11) raises questions. What justifies granting it such a central role? What are its practical and theoretical consequences?