世界所有前进的动力都归功于不安分的人;幸福的人不可避免地把自己局限在古老的界限内。
The world owes all its onward impulses to men ill at ease; the happy man inevitably confines himself within ancient limits.
The difference between a dream and reality is action.
实现明天的唯一限制是我们今天的疑虑。