The past is a shadow that follows us everywhere.
有成就感的人会把世界看成一个友好的世界，并乐于看到它照原样保持下去，但失意者却会乐于看到世界急遽改变。
在科学中，唯一不变的就是变化。
The end of history will be a very sad time. The struggle for recognition, the willingness to risk one's life for a purely abstract goal, the worldwide ideological struggle that called forth daring, courage, imagination, and idealism, will be replaced by economic calculation, the endless solving of technical problems, environmental concerns, and the satisfaction of sophisticated consumer demands.