 Remarkable in Darwin’s argument, however, is the way in which he draws selectively from these preexistent traditions to undermine the species “realism” assumed within these. One tradition—what can be considered in his immediate context the Linnaean tradition—regarded species in the sense of universals of logic or class concepts, whose “reality” rested in many cases on divine creation. The alternative “Buffonian” tradition viewed species in the sense of material lineages of descent whose fixity was determined by some kind of immanent principle, such as an “internal mold” or specifying vital force (see  evolutionary thought before Darwin  3.3). The result in Darwin’s hands is a complex interweaving of concepts of varieties, races, sub-species, tribes, and natural families that can be shown to represent different traditions of discussion in the literature of the period. This creative conflation also led to many confusions about how Darwin actually did conceive of species and species change in time (Sloan 2008).