The average man who uses a telephone could not explain how a telephone works. He takes for granted the telephone, the railway train, the linotype, the airplane, as our grandfathers took for granted the miracles of the gospels. He neither question nor understand them. It is as though each of us investigated and made his own a tiny circle of facts. Knowledge outside the day’s work is regarded by most men as a gewgaw. Still we are constantly in reaction against our ignorance. We rouse ourselves at intervals and speculate. We revel in speculations about anything at all --- about life after death or about such questions as that which is said to have puzzled Aristotle, “Why sneezing from noon to midnight was good, but from night to noon unlucky?” One of the greatest joys known to man is to take such a flight into ignorance in search of the knowledge. The great pleasure of ignorance is, after all, the pleasure of asking questions. The man who has lost this pleasure or exchanged it for the pleasure of dogma, which is the pleasure of answering, is already beginning to stiffen. One envies so inquisitive a man as Jewell, who sat down to the study of physiology in his sixties. Most of us have lost the sense of our ignorance long before that age. We even become vain of our squirrel’s hoard of knowledge and regard increasing age itself as a school of omniscience. We forget that Socrates was famed for wisdom not because he was omniscient but because he realized at the age of seventy that he still knew nothing.

    一般用电话的人都不懂电话是怎样工作的，他们总是把电话、铁路、排字机、飞机等看成是自然而然的东西，就像我们的祖先觉得福音书里的奇事都是很自然的一样。他们不懂，也不问。似乎我们每个人都只钻研、弄懂很小范围内的一些事情。大多数人都认为日常生活之外的知识是花里胡哨的东西。然而，我们也在不停地抗拒着我们的无知。有时，我们会振奋起来，进行思考。我们会信手拈来一个问题，然后沉浸在思考中――如死后的生活，或者其它问题，比如一个据说曾经困扰亚里士多德的问题：“为什么从中午到午夜打喷嚏是好运气，而从午夜到中午打喷嚏代表坏运气？”在寻找知识的过程中陷入无知，是人类的一大乐事。无知的快乐，说到底，是提问题的快乐。一个已经不会提问的人，一个用教条的答案回答问题并以此为乐的人，他的头脑已经开始僵化了。我们很羡慕裘伊，他在六十多岁的时候居然开始做下来学习生理学，而大多数人在远未达到这个年龄就已经不知道什么是无知了。我们甚至会为我们的一点浅薄的知识而沾沾自喜，甚至觉得，流逝的时光本身就会自然地给我们所有的知识。我们忘了，苏格拉底之所以流芳百世，不是因为他什么都懂，而是他发现在他七十岁的时候，仍然什么都不懂。