1 Whither Neutral Monism?

1. Neutral monism is the monistic metaphysical thesis about the ultimate nature of reality according to which there is only one underlying commonality to both mind and matter, both of which can be reduced to and constructed from that underlying commonality. Historically, various authors have defended various forms of monism: a physicalist monism, a mentalist or spiritualist monism, and neutral monism itself. Physicalist monism contends that the ultimate nature of reality can be accommodated within the confines of the science of physics—when theoretical physics will arrive at a “theory of everything”, mind itself will be accounted for by that theory, combining or overcoming insights from the theory of relativity, quantum physics, string theory, or any other theory of this kind. Mentalist or spiritualist monism contends that the ultimate nature of reality cannot be accommodated within the confines of any natural science, with the possible exception of a natural science of the mind—even the nature of physical entities is ultimately mental or spiritualist. Historically, idealism can be considered as a mentalist or spiritualist metaphysics, but other varieties of the latte