 The motivation for the typing that led to this embarras de richesses was understandable at the time. Russell wished to avoid any potentially vicious circularity that might result from impredicative definitions. According to Russell, it should be illicit to define a class C in a way that involves generalizing about any range of individuals to which C itself would have to belong. Thus, with partitioning into types, the notion of self-membership, along with non-self-membership, could not even be deployed. 