Why did I love this book?
The author seeks to use evolutionary principles to explain why human violence within societies is uncommon whereas violence between societies, expressed mainly as war, is very common. Chimpanzees are a violent species in which both types of violence are extremely common. Males compete for dominance in violent ways and males frequently direct their violence toward females. But with respect to within-society violence humans have “domesticated” themselves, mostly by, over hundreds of thousands of years, killing the most violent and dangerous males. With respect to between-society violence, however, humans remain chimp-like. Chimps are notorious for intercommunity raiding and killing, and the anthropological and archaeological evidence shows that humans are equally notorious. Humans have therefore evolved to be both nice and nasty—and therein lies the paradox expressed in the book’s subtitle.