随机实验是因果推理的黄金标准，但它们并不总是可行的。

The more you know, the less you feel.

当一个人炫耀他自己的智慧时，往往倒会误入歧途。

False happiness renders men stern and proud， and that happiness is never communicated. True happiness renders them kind and sensible， and that happiness is always shared.

我们距离完全理解M理论还很远，但这一旅程已经带来了难以置信的回报。