The causal model is the key to making sense of the world.
也许每一个男子全都有过这样的两个女人,至少两个。娶了红玫瑰,久而久之,红的变了墙上的一抹蚊子血,白的还是"床前明月光";娶了白玫瑰,白的便是衣服上沾的一粒饭黏子,红的却是心口上一颗朱砂痣。
You cannot always control what goes on outside, but you can always control what goes on inside.
Mathematics is the art of giving the same name to different things.