 Pure categoricalism seems to imply that causative roles are only contingently associated to a property. Therefore, on pure categoricalism, a property can possibly have distinct causative roles, which allows it to explain—among other things—the apparent contingency of causative roles and the possibility of recombining a property with distinct causative roles. Its supporters include Lewis (1986b, 2009), Armstrong (1999), Schaffer (2005), and more recently Livanios (2017), who provides further arguments based on the metaphysics of science. Kelly (2009) and Smith (2016) may be added to the list, although they take roles to be non-essential and necessary (for further options, see also Kimpton-Nye 2018, Yates 2018a, Coates forthcoming and Tugby forthcoming).