In the history of biology, knowledge about human differences often has been produced through an interaction with politics and values assumed to be external to science. Two recent books—Jonathan Marks’ Is Science Racist? and Maurizio Meloni’s Political Biology—shed new light on this interplay. While Marks looks into the field of anthropology, Meloni offers a historiographical view on the soft-hard heredity debate. Based on these new contributions, this essay addresses a number of current ways in which society and science conceptualize human (...) differences through categories like race, gender, and class. Especially, this refers to the separation of what is taken as natural and purportedly fixed, from what is cultural and changeable. (shrink)