This essay argues that the rhetoric of science and race have real effects on the characters and relationships in Zadie Smith’s White Teeth. Through reading the anxieties about race, ethnicity, and science that permeate the novel in conjunction with the cybernetic term “black box,” two things become evident. First, race and science become the primary categories through which the characters comprehend each other. Second, characteristics of those categories that are taken for granted, such as what constitutes Britishness in the 21st century, and the certainty of scientific evidence, actually destabilize the relationships they are intended to define.