The iDeal Reader Jacob Bronowski,"The ©The McGraw-Hil Nature of Scientific Companies,2000 Reasoning" It seems impossible that this historian had ever studied the beginnings of a sci- 3 entific discovery.The Scientific Revolution can be held to begin in the year 1543 when there was brought to Copernicus,perhaps on his deathbed,the first printed copy of the book he had finished about a dozen years earlier.The thesis of this book is that the earth moves around the sun.When did Copernicus go out and record this fact with his camera?What appearance in nature prompted his outrageous guess? And in what odd sense is this guess to be called a neutral record of fact? Less than a hundred years after Copernicus,Kepler published (between 1609 and 4 1619)the three laws which describe the paths of the planets.The work of Newton and with it most of our mechanics spring from these laws.They have a solid,matter- of-fact sound.For example,Kepler says that if one squares the year of a planet,one gets a number which is proportional to the cube of its average distance from the sun. Does anyone think that such a law is found by taking enough readings and then squaring and cubing everything in sight?If he does,then,as a scientist,he is doomed to a wasted life;he has as little prospect of making a scientific discovery as an electronic brain has. It was not this way that Copernicus and Kepler thought,or that scientists think 5 today.Copernicus found that the orbits of the planets would look simpler if they were looked at from the sun and not from the earth.But he did not in the first place find this by routine calculation.His first step was a leap of imagination-to lift himself from the earth,and put himself wildly,speculatively into the sun."The earth con- ceives from the sun,"he wrote;and "the sun rules the family of stars."We catch in his mind an image,the gesture of the virile man standing in the sun,with arms out. stretched,overlooking the planets.Perhaps Copernicus took the picture from the drawings of the youth with outstretched arms which the Renaissance teachers put into their books on the proportions of the body.Perhaps he had seen Leonardo's draw- ings of his loved pupil Salai.I do not know.To me,the gesture of Copernicus,the shining youth looking outward from the sun,is still vivid in a drawing which William Blake in 1780 based on all these:the drawing which is usually called Glad Day. Kepler's mind,we know,was filled with just such fanciful analogies;and we know 6 that they were.Kepler wanted to relate the speeds of the planets to the musical intervals.He tried to fit the five regular solids into their orbits.None of these like- nesses worked,and they have been forgotten;yet they have been and they remain the stepping stones of every creative mind.Kepler felt for his laws by way of metaphors, he searched mystically for likenesses with what he knew in every strange corner of nature.And when among these guesses he hit upon his laws,he did not think of their numbers as the balancing of a cosmic bank account,but as a revelation of the unity in all nature.To us,the analogies by which Kepler listened for the movement of the planets in the music of the spheres are farfetched.Yet are they more so than the wild leap by which Rutherford and Bohr in our own century found a model for the atom in,of all places,the planetary system? No scientific theory is a collection of facts.It will not even do to call a theory 7 true or false in the simple sense in which every fact is either so or not so.The Epicureans held that matter is made of atoms 2000 years ago and we are now tempted to say that their theory was true.But if we do so we confuse their notion of matter with our own.John Dalton in 1808 first saw the structure of matter as we do today,The iDeal Reader Jacob Bronowski, ‘‘The Nature of Scientific Reasoning’’ © The McGraw−Hill Companies, 2000 It seems impossible that this historian had ever studied the beginnings of a sci￾entific discovery. The Scientific Revolution can be held to begin in the year 1543 when there was brought to Copernicus, perhaps on his deathbed, the first printed copy of the book he had finished about a dozen years earlier. The thesis of this book is that the earth moves around the sun. When did Copernicus go out and record this fact with his camera? What appearance in nature prompted his outrageous guess? And in what odd sense is this guess to be called a neutral record of fact? Less than a hundred years after Copernicus, Kepler published (between 1609 and 1619) the three laws which describe the paths of the planets. The work of Newton and with it most of our mechanics spring from these laws. They have a solid, matter￾of-fact sound. For example, Kepler says that if one squares the year of a planet, one gets a number which is proportional to the cube of its average distance from the sun. Does anyone think that such a law is found by taking enough readings and then squaring and cubing everything in sight? If he does, then, as a scientist, he is doomed to a wasted life; he has as little prospect of making a scientific discovery as an electronic brain has. It was not this way that Copernicus and Kepler thought, or that scientists think today. Copernicus found that the orbits of the planets would look simpler if they were looked at from the sun and not from the earth. But he did not in the first place find this by routine calculation. His first step was a leap of imagination—to lift himself from the earth, and put himself wildly, speculatively into the sun. “The earth con￾ceives from the sun,” he wrote; and “the sun rules the family of stars.” We catch in his mind an image, the gesture of the virile man standing in the sun, with arms out￾stretched, overlooking the planets. Perhaps Copernicus took the picture from the drawings of the youth with outstretched arms which the Renaissance teachers put into their books on the proportions of the body. Perhaps he had seen Leonardo’s draw￾ings of his loved pupil Salai. I do not know. To me, the gesture of Copernicus, the shining youth looking outward from the sun, is still vivid in a drawing which William Blake in 1780 based on all these: the drawing which is usually called Glad Day. Kepler’s mind, we know, was filled with just such fanciful analogies; and we know that they were. Kepler wanted to relate the speeds of the planets to the musical intervals. He tried to fit the five regular solids into their orbits. None of these like￾nesses worked, and they have been forgotten; yet they have been and they remain the stepping stones of every creative mind. Kepler felt for his laws by way of metaphors, he searched mystically for likenesses with what he knew in every strange corner of nature. And when among these guesses he hit upon his laws, he did not think of their numbers as the balancing of a cosmic bank account, but as a revelation of the unity in all nature. To us, the analogies by which Kepler listened for the movement of the planets in the music of the spheres are farfetched. Yet are they more so than the wild leap by which Rutherford and Bohr in our own century found a model for the atom in, of all places, the planetary system? No scientific theory is a collection of facts. It will not even do to call a theory true or false in the simple sense in which every fact is either so or not so. The Epicureans held that matter is made of atoms 2000 years ago and we are now tempted to say that their theory was true. But if we do so we confuse their notion of matter with our own. John Dalton in 1808 first saw the structure of matter as we do today, 3 4 5 6 7