Twenty years ago, C. J. Cherryh wrote a series of science fiction books, the Faded Sun trilogy. In it, she introduced beings called the regul – cannibalistic frog-like creatures who brought forth the best in their race by ritually chasing down and eating their own children. Whatever children were quick enough and clever enough to survive to adulthood were thereby vindicated as the best. When one of the human characters asked how the regul could be so bloodthirsty, the regul’s reply upset my teenage worldview. The regul pointed out that their methods of winnowing the population was really no different...