Abstract
James’s positivism is different from Comte’s, Clifford’s, and the logical positivists’. Notably, it presupposes a difference between natural–scientific inquiries and the metaphysical inquiry he calls radical empiricism. Equally importantly, the positivism of James’s great book, The Principles of Psychology, studies the cerebral conditions of the will. This cerebralism is necessary background for understanding James’s voluntarism, the will–to–believe doctrine that came later. James’s positivism goes hand–in–hand with his value pluralism; they are responsible for different domains of inquiry, natural-scientific and ethical, respectively. It is a mistake to impose a “master moral syllogism” onto the former, implying that all facts are constituted by the will as guided by a utilitarian moral principle. Cerebral shaping of the will occurs not only through the “front door” of experience, especially in the formation of habit, but also through the “back stairs” of mutation and natural selection, which creates brains suited to different pursuits. The brain is no tabula rasa.