  Thus, Du Bois worries that what he has called a “race concept” is not, strictly speaking, a concept, for he sees that it is not the sort of concept that can be defined by specifying a set of non-contradictory and hence logically coherent conditions for its proper application. Contradiction can inhabit the race concept, because Du Bois, like Nietzsche, allows that historically formed concepts may comprise discordant interpretations of the meaning of one and the same set of phenomena. The race concept is “illogical,” but is not for that reason without the efficacy characteristic of “forces,” “facts,” and “tendencies” (Du Bois, 1940, 67). Indeed, the efficacy of the concept is such that, internal inconsistencies notwithstanding, it has dominated Du Bois’s life. Du Bois’s exemplification of the race concept is his subjection to it. Reminiscent, again, of Nietzsche, he holds that historically formed concepts can function as mechanisms of power and control (Gooding-Williams, 2014,  167).[25]