不学习历史的人注定要重复错误。

There is no point treating a depressed person as though she were just feeling sad, saying, 'There now, hang on, you'll get over it.' Sadness is more or less like a head cold- with patience, it passes. Depression is like cancer.

自然科学是人类文化的一部分，它与艺术或宗教一样具有人性。

正是依靠观察和思考才能找到方法。所以我们必须不断挖掘和钻研。