In his Prologue, Jared Diamond gives a number of common answers to Yali's question. Among them are:
- Biological explanations. These explanations are essentially racist. They say that Europeans are simply genetically superior to people like Yali. Typically, they argue that European superiority shows up in the "fact" that Europeans have higher levels of intelligence.
- Climate-based explanations. These argue that Europeans became superior because they lived in a harsher environment. Tropical people didn't have to work hard for their livings and so did not need technology and such. Because Europeans lived in tough, cold climates, they had to be more ingenious in order to survive. This made them more inventive and led to technology.
- River-based explanations. These argue that civilizations arose in lowland river valleys in dry climates. Civilization arose there because it was necessary in order to organize society to create irrigation works.
These are the three major explanations that Diamond mentions in the beginning of this book.