计算复杂性的研究不仅仅是关于问题的分类；它是关于理解计算本身的本质。

最好的数学是简单的，但又不至于过于简单。

〈在广东第一女子师范学校校庆纪念会的演说〉，1924年4月4日

In dreams, you don't need to make any distinctions between things. Not at all. Boundaries don't exist. So in dreams there are hardly ever collisions.

Courtesy costs nothing. Lower the toilet seat after use. Let the people in the elevator exit before you enter. Return shopping carts to their designated areas. When you borrow something， return it better shape (filled up， cleaned) than when you got it.

The primary function of law is to provide a framework for social order.

世界上真正的悲剧不是正确与错误之间的冲突，而是两种正确之间的冲突。

He knew that the world was made for men and that men were made to look at it.