卡尔·萨根打了一个比喻,生存在二度空间的人只能看到身边尽是一些线,没有高度的概念,抬头也看不到头上的事物,但有一天,有一位生活于三度空间的人走来,把那位居住在二度空间的人带到三度空间去,那个只有平面的人终于看到原来住在隔邻的那位太太是三角形的,那位下面的老伯原来是四方形的,原来他的老婆是圆形的。但实情是二度空间的人没法去到三度空间,而他也没法想像三度空间会是一个怎样的世界,甚至没法知道或去证实有这个三度空间的存在,就正如我们只能凭理论去推敲,这个世界或许有四度空间的存在一样。女人问男人:“你终于肯听电话啦?”男人懒洋洋说:“哦!你找我有事嘛?”女人很担心地说“我已经找了你一个星期,为什么你不接电话?我还以为你出了什么意外?究竟发 Karl Sagan made a metaphor, people living in second space can only see the side is full of some lines, there is no high degree of concept, looked up and can not see the things on his head, but one day, one living in three degrees The person in space came and took the man who lived in the second space to the third space, and the plain man finally saw that the wife who lived in the immediate vicinity was a triangle, and the old man below It is a square, so his wife is round. But the truth is that second-degree people can not go to third-degree space, and he can not imagine how third-degree space can be a kind of world. They can not even know or prove the existence of the third degree of space. Just as we Only theoretical deduction, the world may have the existence of four degrees of space. A woman asked a man: ”You man finally lazy to say? “ Man lazily said: ”Oh! You find me something? “ The woman is very worried to say ”I have found you for a week, why do not you Answer the phone? I thought you had any accidents?