一个良好的世界需要知识、善良和勇气；它不需要对过去的后悔，也不需要被无知之人长时间前说过的话所束缚的自由智慧。
A good world needs knowledge， kindliness， and courage； it does not need a regretful hankering after the past or a fettering of the free intelligence by the words uttered long ago by ignorant men.
The whole problem with the world is that fools and fanatics are always so certain of themselves， and wiser people so full of doubts.