The main task in life is simply this: to identify and separate matters so that I can say clearly to myself which are externals not under my control, and which have to do with the choices I actually control.

A good mathematician is not one who knows all the answers, but one who asks the right questions.

Excellence is not an act, but a habit.

我不习惯安逸。我只在不舒服的时候才感到舒服。