出自先秦《荀子·性恶》引古语。不知儿子的为人，看看他的朋友就清楚了；不知国君是否贤明，看看他左右的大臣是什么德行就知道了。

"Life is a series of natural and spontaneous changes. Don't resist them; that only creates sorrow. Let reality be reality. Let things flow naturally forward in whatever way they like."

"The refusal to rest content, the willingness to risk excess on behalf of one's obsessions, is what distinguishes artists from entertainers."

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。

Pain can be a form of knowledge.