History is filled with moral doctrines; doctrines that tell us where we are, what to do, and the kind of future we're striving for. These moral systems differ significantly around the world, and oftentimes in spectacular ways. In the 20th century many Western intellectuals took these differences as proof that morality was always a social construct used to maintain power and authority by an oppressive elite. After all, if what is considered 'moral' in one culture is absolutely 'immoral' in...