The greatest wisdom is to realize one's own ignorance.

人生四然：来是偶然，去是必然，尽其当然，顺其自然。

It's enough for me to be sure that you and I exist at this moment.

试图在不激发学生学习欲望的情况下进行教学的老师，就像在冷铁上敲打。

I pursue no objectives, no systems, no tendency; I have no program, no style, no direction.

事情过后议论别人，身在局外议论局内人，是做学问的人最容易犯的毛病。在事后议论别人，往往将聪明人说得极其愚笨；身在局外议论局内的人，往往将困难的事情说得极其容易，这两种毛病都是由待人不忠诚、不宽容而引起的。

"The past is a shadow that follows us, but it does not have to define us."

Immigration has a much smaller effect on native wages than most people believe.

"A key insight in computational learning theory is that the complexity of a learning problem is determined by the complexity of the hypothesis space and the amount of data available."