"A mathematician is a device for turning coffee into theorems."

实现明天的唯一限制是我们今天的疑虑。

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.

观察他交往的是什么人，就能知道他的品行如何。

幸福的秘密是自由，自由的秘密是勇气。