 Gregory Landini’s influential discussion of Russell’s neutral monism (Landini 2011: ch. 6) illustrates the importance of the distinction between criteria (1) and (3). Landini assumes that (3) captures Russell’s idea of neutrality. This allows Landini to conclude that Russell is a physicalist and a neutral monist (see Landini, 280, 291, 297). According to Landini, Russell is a neutral monist because every basic entity can be a constituent of both physical and mental non-basic entities; and Russell is a physicalist because all basic entities of his system are  physical.[1]