The history of scientific classifications is obviously not the history of human variety. The history of scientific classifications of human variety is the history of how those schemes contributed to the scientific ideology of race. It is via this route that the classification or system of classifications of human variety contributed mightily to the formulation of the concept of race. It is not that science alone gave us our concept of race. The history of the scientific classifications of human variety demonstrates the extent to which scientific classification is a dynamic – sometime cooperative, sometimes contradictory – technology of power. In the nineteenth century, scientific classification was but one of many contributors to racialist and segregationist ideology. There was, of course, much more going on in the world, and certainly the American South's peculiar institution would have made race a concern without any help from or reference to scientific ideology.

And yet, the scientific classification of human variety did serve to legitimize the disciplinary formations which emerged during the nineteenth century: the sciences of life, especially biology and ecology; and the sciences of society, especially sociology, social work and criminology, emerged from the wreckage of polygenism, natural history and political economy. These provided nodal points around which the scientific ideology of race could be formed and manipulated. Once this occurred, the everyday notion of race as the explanation for human variety could become the scientific view, and vice versa.