The greatest obstacle to being heroic is the doubt whether one may not be going to prove one's self a fool; the truest heroism is to resist the doubt; and the profoundest wisdom, to know when it ought to be resisted, and when it be obeyed.

巫术并非源于对普遍力量的抽象概念，也不是神话观念的结果。它是人类在面对危险时感到无助的具体情境的产物。

You have to be willing to grow. Growth is different from something that happens to you. You produce it. You live it. The prerequisites for growth: the openness to experience events and the willingness to be changed by them.

P与NP问题是计算机科学中最重要的一个问题之一。