The more difficult the victory, the greater the happiness in winning.

On innovation: "I think frugality drives innovation， just like other constraints do. One of the only ways to get out of a tight box is to invent your way out."

You can tell whether a man is clever by his answers. You can tell whether a man is wise by his questions.

The study of black holes has revolutionized our understanding of space and time.

生活里有两个悲剧：一个是没有得到我们想要的；另外一个是得到了。