The book attempts to explain why
Eurasian and
North African civilizations have survived and conquered others, while arguing against the idea that Eurasian
hegemony is due to any form of Eurasian
intellectual,
moral, or
inherent genetic superiority. Diamond argues that the gaps in power and technology between human societies originate primarily in environmental differences, which are amplified by various
positive feedback loops. When cultural or genetic differences have favored Eurasians (for example,
written language or the development among Eurasians of resistance to
endemic diseases), he asserts that these advantages occurred because of the influence of geography on societies and cultures (for example, by facilitating commerce and trade between different cultures) and were not inherent in the Eurasian
genomes.