Ernst Mach saw his position as part of a movement, including "a whole host of philosophers—positivists, critical empiricists, adherents of the philosophy of immanence, and certain scientists... [who] have entered upon paths which...converge almost towards one point." Bertrand Russell, who stood at the end of that presaged development, in turn claimed that Mach had "inaugurated the movement" toward neutral monism.¹ Within the context of a neutral monist movement in Austria, Britain, and America, some characteristic theses emerge such as the principle of psychophysical parallelism, the necessity of a functional and causal presentation of particulars or elements, sometimes events, the assumption of "unsensed sensibilia" in matter and other minds and so forth.