One person making a wrong decision affects the whole country.

[W]hat makes patriotic and religious fanatics such dangerous opponents is not the deaths of the fanatics themselves, but their willingness to accept the deaths of a fraction of their number in order to annihilate or crush their infidel enemy.

The rate of human invention is faster, and the rate of cultural loss is slower, in areas occupied by many competing societies with many individuals and in contact with societies elsewhere.

One way to explain the complexity and unpredictability of historical systems, despite their ultimate determinacy, is to note that long chains of causation may separate final effects from ultimate causes lying outside the domain of that field of science.

[T]he values to which people cling most stubbornly under inappropriate conditions are those values that were previously the source of their greatest triumphs.

The Anasazi did manage to construct in stone the largest and tallest buildings erected in North America until the Chicago steel girder skyscrapers of the 1880s.

Today Charles Darwin is best known for establishing the fact of evolution and for recognizing the major role of natural selection in driving it.