The postulate of "the psychic unity of mankind" states that all human beings, regardless of culture or race, share the same basic psychological and cognitive make-up; we are all of the same kind. The postulate was originally formulated by Adolf Bastian, the "father of German anthropology", who was a classical German humanist and a cultural relativist, who believed in the intrinsic value of cultural variation. Bastian passed it on to his similarly minded student, Franz Boas, who, as the "father of American anthropology", transmitted it on to all of his students. Edward B. Tylor introduced it to 19th century British evolutionist anthropology, where it became a fixture, defended by all the major British evolutionists. The postulate, indeed, was essential to the great comparative projects of evolutionism, which would be futile if cultural differences were determined by differing biology. For the same reason, it has been central to later compative projects, e.g. Radcliffe-Brown's, Barth's, Steward's, Godelier's etc. Today, the postulate is shared by all anthropologists (exceptions are hard to think of).