Aristotelian neurophilosophy for big children

At the beginning of the twentieth century, Max Weber (1958 [1919], p. 143) did not exaggerate much when he claimed that, ‘aside from certain big children who are indeed found in the natural sciences’, few people still believed that science could serve as a key to moral action. David Hume’s eighteenth-century dictum that ought sentences could not be deduced from is sentences had just been cemented by G.E. Moore’s ruling against the ‘naturalistic fallacy’ (Shapin, 2008, p. 10f). The conviction that empirical findings had no moral philosophical implications was closely associated with philosophers’ emergent opposition to the philosophical significance of scientific knowledge tout court. By forcing empirically oriented researchers out of philosophy departments, philosophy was temporarily constituted as the domain of purely conceptual thought (Kusch, 1995). In the 1960s, at about the same time as French structuralists and poststructuralists began to do away again with the separation of philosophy and the human sciences, American philosophers such as Wilfrid Sellars and W.V.O. Quine also called into question the opposition of the empirical and the conceptual in analytic philosophy. In this vein, Patricia Churchland and her husband Paul Churchland reconnected philosophy and brain research in what they called neurophilosophy (Churchland, 1986). After the bulk of their work had focused on the philosophy of mind and the philosophy of science, Patricia Churchland’s new book Braintrust provides an account of what neuroscience tells us about morality. Pace Weber, Moore and company, Churchland self-consciously regresses to being one of those ‘big children’ who maintain the ethical significance of brain research. But maybe it is time to pause before lapsing into Weber’s infantilization of ethical naturalists. Anticipating that her neurophilosophical approach to morality will be dismissed as a naturalistic fallacy, Churchland opens the book with her own reading of Hume as a thinker who not only denied that one could logically derive an ought statement from statements about what is, but also advocated naturalism in moral philosophy grounding moral behavior in human nature, especially in the passions, rather than in the supernatural or in reason. She agrees with Hume that, in terms of deductive logic, ought never follows from is. But Churchland also points out that most practical and social problems, including moral ones, do not require logical deduction, but probabilistic inference and circumstantial deliberation. ‘Our brains’, she argues, usually have to ‘figure out’ what are better or worse choices (without there being a uniquely right one) by drawing on knowledge, perceptions, emotions and an understanding of a given situation, balancing a multitude of considerations against each other (pp. 4–7). Neuroscience helps us to understand the physiological mechanisms involved in such moral decision making. Churchland provides a well-informed overview of the current state of research in a broad range of relevant fields, from behavioral genetics to neuroeconomics and from primatology to biological psychiatry. She is particularly interested in the role of the hormone and neuromodulator oxytocin as one of the endocrinological foundations of ‘brain-based values’. What human brains care about, Churchland argues, is the organism’s own well-being, but also the welfare of kith and kin – which can lead to inner conflicts to be resolved by cultural practices, conventions and institutions (p. 12f). In the evolution of mammalian sociality, oxytocin has come to play a central role in caring for others by mediating attachment as the ‘neural platform for morality’ (p. 16). Churchland dismisses the doctrine of the naturalistic fallacy because she believes that our values – at least, in their most basic form – are in the