Historically, the answers to "Yali's Question" have focused on some innate differences between Yali's people (or other non-Europeans) and Europeans. According to Diamond, these explanations include "assuming biological differences between peoples," the "stimulatory effects" of the colder European climates, the "supposed importance of lowland river valleys in dry climates, and a variety of cultural differences that gave Europeans an advantage in their contacts with native peoples around the world. Diamond's overall argument is that, in his own words:
History followed different courses for different peoples because of differences among people's environments, not because of biological differences among peoples themselves.
He specifically refutes the foundations of all of the theories described above, ultimately contending that accidents of geography played a major role in enabling Europeans to amass the "guns, germs, and steel" that made it possible for them to conquer and dominate many of the world's peoples.
Source: Jared Diamond, Guns, Germs, and Steel: The Fates of Human Societies (New York: W.W. Norton and Company, 1999)18-25.