The Lessons of History

by Will Durant

The challenges may come from a dozen sources, and may by repetition or combination rise to a destructive intensity. Rainfall or oases may fail and leave the earth parched to sterility. The soil may be exhausted by incompetent husbandry or improvident usage. The replacement of free with slave labor may reduce the incentives to production, leaving lands unfilled and cities unfed. A change in the instruments or routes of trade—as by the conquest of the ocean or the air—may leave old centers of civilization becalmed and decadent, like Pisa or Venice after 1492. Taxes may mount to the point of discouraging capital investment and productive stimulus. Foreign markets and materials may be lost to more enterprising competition; excess of imports over exports may drain precious metal from domestic reserves. The concentration of wealth may disrupt the nation in class or race war. The concentration of population and poverty in great cities may compel a government to choose between enfeebling the economy with a dole and running the risk of riot and revolution.