The article deals with the Herdero-Humboldtian legacy of Franz Boas’ anthropology. Herder’s theses on the origin of language and the Humboldtian notion of language as an “internal form” accompanying the development of the mind articulate the universal and the particular, opening up a new way of thinking about humanity in its unity and diversity. As Herder did before him, Humboldt stresses the importance of individual languages for the study of the human mind. This philological path is decisive for the development of the Völkerkunde, as it prescribes a method based on the attention paid to cultural singularity. At the end of the nineteenth century, however, racialist physical anthropology combined with political pan-germanism upset this balance by using the universal as an ethnocentric yardstick against which singularities are to be assessed and possibly excluded from humanity. The present paper shows that in reaction to that movement, Franz Boas’ anthropology uses the philological terrain marked out by Herder and Humboldt in order to overcome racialism in physical anthropology. In that sense, his anthropology remains rooted in the German Völkerkunde, even though it was forged on American soil.