 There are many versions of Russellian Monism. Differences are due, in part, to varying views about the relations between the intrinsic properties, on the one side, and the mental and physical properties, on the other. But the central disagreement concerns the nature of the intrinsic properties. They have been held to be physical (Montero 2015; Pereboom 2015), mental (Bolender 2001), mental and physical (Strawson 2015, 2016), or neutral (Coleman 2014). Accordingly there are physicalist, idealist (mentalist), and neutral monist versions or Russellian monism. The precise nature of these disagreements are difficult to pin down, given the number of different notions of the mental and the physical that are in play in this discussion.