William James’s panpsychism grew out of his “neutral monism”— the view that the fundamental nature of reality is neither mental nor physical, but of some third form that can be regarded as either mental or physical from different viewpoints. To the extent that a neutral monism can be regarded as a dual-aspect view (as in Spinoza’s philosophy), it might be regarded as a kind of panpsychism in its own right; but James’s view developed beyond this, to incorporate mind-like elements into the basic structure of reality. In a notebook of 1909 he wrote: “the constitution of reality which I am making for is of the psychic type” (see Cooper 1990). James’s commitment to panpsychism remains somewhat controversial, since he also advanced a cogent set of objections against a version of the view, which he labelled the “mind dust” theory, in chapter six of The Principles of Psychology ([1890] 1981). These objections are the inspiration for the so-called “combination problem”, around which much of the twenty first century literature on panpsychism focuses. But in the end James’s commitment is quite clear (see James 1909, 1911; Lamberth 1997; and for an excellent analysis of James’s views on mind see Cooper 1990 or chapters 2–4 of Cooper 2002).