ABSTRACT
Ever since the early nineteenth century, when the idea of race as biological human difference became effective for the organization of society, the public has been confident that evident human differences in skin color and morphology could be explained by descriptions of general race factors knowable to scientists. For example, it is believed that black people have some physical thing that makes them black and causes dark skin shades. General race factors, such as blackness, are believed to determine racial membership and cause specific racial traits.
