The most important thing in mathematics is to have a good intuition.

Watch your thoughts, for they become words. Watch your words, for they become actions. Watch your actions, for they become habits. Watch your habits, for they become your character. And watch your character, for it becomes your destiny. What we think, we become.

读古人的著作，与贤能的人交往，最忌讳轻率地表示附和赞同，也不能够轻率地表示异议。之所以会犯这两种过失，都是由于心中缺乏主见，做学问时就掺杂有趋炎附势的成分，不是曲意逢迎便是虚伪矫饰。