Are human cultural differences superimposed upon a universal human nature? The appeal to an essentialist concept of human nature is a defensive reaction to the legacy of racist science left by Darwin's argument in 'The Descent of Man'. Humans are made to appear different in degree from their evolutionary antecedents by attributing the movement of history to a process of culture that differs in kind from the biological process of evolution. The specifications of evolved human nature are supposed to lie in the genes. However human capacities are not gengetically specified but emerge within processes of ontogenetic development. Moreover the circumstances of development are continually shaped through human activity. There is consequently no human nature that has escaped the current of history.