 Thus, in his 1904 article, "The History of Anthropology", Boas wrote that

The historical development of the work of anthropologists seems to single out clearly a domain of knowledge that heretofore has not been treated by any other science.It is the biological history of mankind in all its varieties; linguistics applied to people without written languages; the ethnology of people without historical records; and prehistoric archeology.Historians and social theorists in the 18th and 19th centuries had speculated as to the causes of this differentiation, but Boas dismissed these theories, especially the dominant theories of social evolution and cultural evolution as speculative.