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.

数学的研究对科学的发展就像空气或水一样。

人一定要懂得“礼”之后才能产生恭敬之心，产生恭敬之心以后才能有所尊敬，有所礼让。