数学中真正的挑战不是解决问题，而是提出正确的问题。

Love is the supreme positive emotion, the one that encompasses all others. It is the feeling of positive resonance that you experience when you connect deeply with another person.

The laws that forbid the carrying of arms are laws of such a nature. They disarm only those who are neither inclined nor determined to commit crimes.... Such laws make things worse for the assaulted and better for the assailants; they serve rather to encourage than to prevent homicides, for an unarmed man may be attacked with greater confidence than an armed man.

One tells as few lies as possible only by telling as few lies as possible, and not by having the least possible opportunity to do so.

不和屯积钱财的人争较财富多少；不和热心仕途的人争较地位高下；不和骄傲自夸的人争较名声大小；不和年轻力壮的人争较仪容风度，不和逞强好胜的人争较胜负高低。

刀展示了锋利，而试刀砍头的人将遭到不祥。 

A building must be a celebration of life.