The ideas of economists and political philosophers， both when they are right and when they are wrong， are more powerful than is commonly understood. Indeed the world is ruled by little else. Practical men， who believe themselves to be quite exempt from any intellectual influence， are usually the slaves of some defunct economist.

The entrepreneur always searches for change, responds to it, and exploits it as an opportunity.

随着劳动分工和机械应用的扩大，工人之间的竞争加剧，他们的工资也越来越低。