Para.8 All science is the search for unity in hidden likeness.The search may be on a grand scale,as in the modern theories which try to link the fields of gravitation and electromagnetism.But we do not need to be browbeaten by the scale of science.There are discoveries to be made by snatching a small likeness from the air too,if it is bold enough.In 1935 the Japanese physicist Hideki Yukawa wrote a paper which can still give heart to a young scientist.He took as his starting point the known fact that waves of light can sometimes behave as if they were separate pellets.From this he reasoned that the forces which hold the nucleus of an atom together might sometimes also be observed as if they were solid pellets.A schoolboy can see how thin Yukawa's analogy is,and his teacher would be severe with it.Yet Yukawa without a blush calculated the mass of the pellet he expected to be,and waited.He was right;his meson was found,and a range of other mesons,neither the existence nor the nature of which had been suspected before.The likeness had borne fruit. Para.9 The scientist looks for order in the appearances of nature by exploring such likenesses.For order does not display itself of itself,if it can be said to be there at all,it is not there for the mere looking. There is no way of pointing a finger or camera at it;order must be discovered and,in a deep sense,it must be created.What we see,as we see it,is mere disorder. Para.10 This point has been put trenchantly in a fable by Karl Popper.Suppose that someone wishes to give his whole life to science.Suppose that he therefore sat down,pencil in hand,and for the next twenty, thirty,forty years recorded in notebook after notebook everything that he could observe.He may be supposed to leave out nothing:today's humidity,the racing results,the level of cosmic radiation and the stock-market prices and the look of Mars,all would be there.He would have compiled the most careful record of nature that has ever been made;and,dying in the calm certainty of a life well spent,he would of course leave his notebooks to the Royal Society.Would the Royal Society thank him for the treasure of a lifetime of observation?It would not.The Royal Society would treat his notebook exactly as the English bishops have treated Joanna Southcott's box.It would refuse to open them at all,because it would know without looking that the notebooks contain only a jumble of disorderly and meaningless items. Para.11 Science finds order and meaning in our experience,and sets about this in quite a different way.It sets about it as Newton did in the story which he himself told in his old age,and of which the schoolbooks give only a caricature.In the year 1665,when Newton was 22,the plague broke out in Southern England,and the University of Cambridge was closed.Newton therefore spent the next 18 months at home,removed from traditional learning,at a time when he was impatient for knowledge and,in his own phrase,"I was in the prime of my age for invention."In this eager,boyish mood,sitting one day in the garden of his widowed mother,he saw an apple fall.So far the books have the story right;we think we even know the kind of apple;tradition has it that it was a Flower of Kent.But now they miss the crux of the story.For what struck the young Newton at the sight was not the thought that the apple must be drawn to the earth by gravity;that conception was older than Newton.What struck him was the conjecture that the same force of gravity,which reaches to the top of the tree,might go on reaching out beyond the earth and its air,endlessly into space.Gravity might reach the moon:this was Newton's new thought;and it might be gravity which holds the moon in her orbit.There and then he calculated what force from the earth(falling off as the square of the distance)would hold the moon,and compared it with the known force of gravity at tree height.The forces agreed;Newton says laconically,"I found them answer pretty nearly."Yet they agreed only nearly:the likeness and the approximation go together,for no likeness is exact.In Newton's science modern sciences is full grown.Para. 8 All science is the search for unity in hidden likeness. The search may be on a grand scale, as in the modern theories which try to link the fields of gravitation and electromagnetism. But we do not need to be browbeaten by the scale of science. There are discoveries to be made by snatching a small likeness from the air too, if it is bold enough. In 1935 the Japanese physicist Hideki Yukawa wrote a paper which can still give heart to a young scientist. He took as his starting point the known fact that waves of light can sometimes behave as if they were separate pellets. From this he reasoned that the forces which hold the nucleus of an atom together might sometimes also be observed as if they were solid pellets. A schoolboy can see how thin Yukawa’s analogy is, and his teacher would be severe with it. Yet Yukawa without a blush calculated the mass of the pellet he expected to be, and waited. He was right; his meson was found, and a range of other mesons, neither the existence nor the nature of which had been suspected before. The likeness had borne fruit. Para. 9 The scientist looks for order in the appearances of nature by exploring such likenesses. For order does not display itself of itself; if it can be said to be there at all, it is not there for the mere looking. There is no way of pointing a finger or camera at it; order must be discovered and, in a deep sense, it must be created. What we see, as we see it, is mere disorder. Para. 10 This point has been put trenchantly in a fable by Karl Popper. Suppose that someone wishes to give his whole life to science. Suppose that he therefore sat down, pencil in hand, and for the next twenty, thirty, forty years recorded in notebook after notebook everything that he could observe. He may be supposed to leave out nothing: today’s humidity, the racing results, the level of cosmic radiation and the stock-market prices and the look of Mars, all would be there. He would have compiled the most careful record of nature that has ever been made; and, dying in the calm certainty of a life well spent, he would of course leave his notebooks to the Royal Society. Would the Royal Society thank him for the treasure of a lifetime of observation? It would not. The Royal Society would treat his notebook exactly as the English bishops have treated Joanna Southcott’s box. It would refuse to open them at all, because it would know without looking that the notebooks contain only a jumble of disorderly and meaningless items. Para. 11 Science finds order and meaning in our experience, and sets about this in quite a different way. It sets about it as Newton did in the story which he himself told in his old age, and of which the schoolbooks give only a caricature. In the year 1665, when Newton was 22, the plague broke out in Southern England, and the University of Cambridge was closed. Newton therefore spent the next 18 months at home, removed from traditional learning, at a time when he was impatient for knowledge and, in his own phrase, “I was in the prime of my age for invention.” In this eager, boyish mood, sitting one day in the garden of his widowed mother, he saw an apple fall. So far the books have the story right; we think we even know the kind of apple; tradition has it that it was a Flower of Kent. But now they miss the crux of the story. For what struck the young Newton at the sight was not the thought that the apple must be drawn to the earth by gravity; that conception was older than Newton. What struck him was the conjecture that the same force of gravity, which reaches to the top of the tree, might go on reaching out beyond the earth and its air, endlessly into space. Gravity might reach the moon: this was Newton’s new thought; and it might be gravity which holds the moon in her orbit. There and then he calculated what force from the earth (falling off as the square of the distance) would hold the moon, and compared it with the known force of gravity at tree height. The forces agreed; Newton says laconically, “I found them answer pretty nearly.” Yet they agreed only nearly: the likeness and the approximation go together, for no likeness is exact. In Newton’s science modern sciences is full grown