The difference between a good business and a bad business is that good businesses throw up one easy decision after another. The bad businesses throw up painful decisions time after time.

"In observational studies, we often have to rely on assumptions that are not directly testable."

译文：如果一个人富贵了，就会有人接近巴结他；如果一个人变得贫贱了，原来与他亲近的人就会离开他。

不要害怕失败，要害怕不去尝试。

天生犯罪人是其自身组织的受害者。

The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.

在弦理论中，所有粒子都是微小超对称弦的振动。