The average man who uses a telephone couldn't explain how a telephone works. He takes for granted the telephone, the railway train , the airplane, as our grandfathers took for granted the miracles of the gospels . He neither questions nor understands them. It is as though each of us investigated and  _  only a tiny circle of facts. Knowledge outside the day's work is regarded by most men as a gewgaw .Still we are usually in reaction against our ignorance.We excite ourselves sometimes and think deeply.We enjoy thinking about anything at allabout life after death or about such questions as 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 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 ignorance long before that age.We even become proud of our squirrel' store -house of knowledge and regard increasing age itself as a school of omniscience  .We forget that Socrates was famous for wisdom not because he was Mr. know-all but because he realized at the age of seventy that he still knew nothing. From the passage we can see the most joyful the writer think is_.
to master useful knowledge to know a great deal just as Socrates to seek the truth to learn at one's sixties