Why did Homo sapiens triumph over other Homo species? And then how did we become the dominant species on the planet? Academic Hanno Sauer addresses these questions and more in his insightful book “The Invention of Good and Evil: A World History of Morality.”

One reason for our success is that we, as a social animal, have a spontaneous and surprisingly flexible capacity for co-operation. Modern group experiments show that humans are intrinsically generous and altruistic but that an individual ...