"There is, anyway, little historical evidence to suggest that a permissive attitude towards the killing of one category of human beings leads to a breakdown of restrictions against killing other humans. Ancient Greeks regularly killed or exposed infants, but appear to have been at least as scrupulous about taking the lives of their fellow-citizens as medieval Christians or modern Americans. In traditional Eskimo societies it was the custom for a man to kill his elderly parents, but the murder of a normal healthy adult was almost unheard of."
1.Of course, this overlooks the additional fact that ancient cultures were generally warrior cultures. So the body count was quite high.
2.How does Singer know the murder rate among traditional Eskimos? Did they keep written records?