Resurgent
polygenists argued that the races were different species, and that their differentiation was an indication of separate origins.
Prichard was actively writing against
polygenists such as the anatomist Robert Knox, who argued that the different human races were separate creations (e.
At the same time, she elucidates the many ways in which Humboldt's passionate anti-slavery stance was silenced in North America by Humboldt's student Louis Agassiz and other
polygenists of the day.
Although Wilson employed racial categories in his analysis, he did not conceive of them as biologically fixed or as arising from separate acts of creation as did
polygenists such as Josiah Nott, but rather as the result of divergent historical development.
The counter argument came from the
polygenists who abandoned scripture and claimed human races to be separate biological species.
Eventually both Evangelicals and
polygenists were trumped by the new monogenism of the Darwinists who argued for the evolution of a single human species but at different rates that had led to longstanding and profound differences between 'races' measured physically according to the shape of the skull, the hue of the skin or the curl of the hair, or culturally through the progress of institutions, intellect or morality (Kenny 2007; Stocking 1968:56; 1987:148-50).
Graves 2005a points out that Charles Darwin was actually one of first naturalists to dispute the claim of the
polygenists that there were separate species of humans.
Southern politicians such as Jefferson Davis, Thomas Clingman, and James Henry Hammond all used
polygenists arguments in speeches and correspondence.
Moreover, the
polygenists used evolution to affirm "that races had been separate long enough to evolve major inherited differences in talent and intelligence.
In the United States at this period, the issues of racial difference and biological evolution were being hotly debated between monogenists, who held that humans had originated as a single type but that due to environmental factors had evolved into various racial groups, and
polygenists, who felt that humankind had from its earliest beginnings been divided into distinct races.
The shift in the predominance of the
polygenists and the monogenists during the nineteenth century, for example, was not a revolutionary one and did not constitute a "paradigm shift.
The group of
polygenists whose work became known as the "American School of Ethnology," such as Samuel George Morton, Josiah Nott, the Briton George Gliddon, and Louis Agassiz, argued that measurements of cranial cavities and studies of material culture proved scientifically that nonwhites were permanently inferior to whites.
