The Biological Basis of Moral Sentiment in Active Inference and Self-Conscious Agency

We propose a non-metaphysical, biologically grounded account of moral sentiment derived from the structure of self-conscious agency. Drawing on Active Intersubjective Inference (AISI), which grounds self-consciousness in socially embedded recursive self-modeling within an active inference architecture, we argue that two core moral sentiments — compassion and responsibility — arise constitutively from the structure of self-consciousness and freedom rather than as evolutionary, cultural, or rational additions to a morally neutral cognitive system. Compassion follows from the underdetermined and interdependent character of personal identity in recursive social self-modeling; responsibility follows from the sense of authorship intrinsic to second-order agency. These sentiments provide guiding principles and motives for ethical choice but rarely determine exact solutions: they function as a compass whose route must be negotiated. We examine alignments and contrasts with major ethical traditions, with particular attention to Rawlsian fairness, which we reinterpret as the natural reasoning of self-conscious agents whose identities are structurally interdependent — everybody, in this sense, already behaves like a Rawlsian. We close by indicating implications for moral psychology, the cultivation and dissemination of virtue, and the social and political conditions of moral agency.