  Other critics of Appiah’s reading of Du Bois have been less inclined than Outlaw to defend or to attribute to Du Bois a definition of race involving biological characteristics; rather they have tended to argue that, Appiah’s arguments to the contrary, Du Bois succeeded in advancing a plausible, non-biological, socio-historical definition of race. Paul Taylor (2000), for example, takes issue with Appiah’s claim that Du Bois’s appeal to “common history” as a criterion of individuation is circular, arguing that Appiah misconstrues Du Bois’s understanding of what it means for two individuals to have a history in  common.[14]  Ronald Sundstrom (2003) also defends Du Bois’s socio-historical definition, arguing that, on a metaphysical pluralist reading, it can do the work of individuation that Appiah says it cannot do. For Taylor and Sundstrom, Du Bois was a racial realist who cogently defended the thesis that race is a social kind.