And, if we can forget books, it is as easy to forget the months and what they showed us, when once they are gone.  Just for the moment I tell myself that I know May like the multiplication table and could pass an examination on its flowers, their appearance and their order.  To-day I can affirm confidently that the buttercup has five petals.  (Or is it six?  I knew for certain last week.) But next year I shall probably have forgotten my arithmetic, and may have to learn once more not to confuse the buttercup with the celandine.  Once more I shall see the world as a garden through the eyes of a stranger, my breath taken away with surprise by the painted fields.  I shall find myself wondering whether it is science or ignorance which affirms that the swift (that black exaggeration of the swallow and yet a kinsman of the humming-bird) never settles even on a nest, but disappears at night into the heights of the air.  I shall learn with fresh astonishment that it is the male, and not the female, cuckoo that sings.  I may have to learn again not to call the campion a wild geranium, and to rediscover whether the ash comes early or late in the etiquette of the trees.  A contemporary English novelist was once asked by a foreigner what was the most important crop in England.  He answered without a moment’s hesitation:  “Rye.”  Ignorance so complete as this seems to me to be touched with magnificence; but the ignorance even of illiterate persons is enormous.  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 aeroplane, 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 made his own only 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 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 Jowett, 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 realised at the age of seventy that he still knew nothing.