Then, too, there is improved education and, in particular, the increased understanding that each of us shares a common humanity with members of other races and with the other sex — both deeply unbiblical ideas that come from biological science, especially evolution. One reason black people and women and, in Nazi Germany, Jews and gypsies have been treated badly is that they were not perceived as fully human. The philosopher Peter Singer, in Animal Liberation, is the most eloquent advocate of the view that we should move to a post-speciesist condition in which humane treatment is meted out to all species that have the brain power to appreciate it. Perhaps this hints at the direction in which the moral Zeitgeist might move in future centuries. It would be a natural extrapolation of earlier reforms like the abolition of slavery and the emancipation of women.
Richard Dawkins, The God Delusion (p.271)
