In Pursuit of the Unknown by Ian Stewart Read Free Book Online Page B

metropolis of half a million people. The arts flourished, and science was in the early stages of an ever-accelerating ascendancy. The Royal Society, perhaps the oldest scientific society now in existence, had been founded five years earlier, and Charles had granted it a royal charter. The rich lived in impressive houses, and commerce was thriving, but the poor were crammed into narrow streets overshadowed by ramshackle buildings that jutted out ever further as they rose, storey by storey. Sanitation was inadequate; rats and other vermin were everywhere. By the end of 1666, one fifth of London’s population had been killed by bubonic plague, spread first by rats and then by people. It was the worst disaster in the capital’s history, and the same tragedy played out all over Europe and North Africa. The king departed in haste for the more sanitary countryside of Oxfordshire, returning early in 1666. No one knew what caused plague, and the city authorities tried everything – burning fires continually to cleanse the air, burning anything that gave off a strong smell, burying the dead quickly in pits. They killed many dogs and cats, which ironically removed two controls on the rat population.
    During those two years, an obscure and unassuming undergraduate at Trinity College, Cambridge, completed his studies. Hoping to avoid the plague, he returned to the house of his birth, from which his mother managed a farm. His father had died shortly before he was born, and he had been brought up by his maternal grandmother. Perhaps inspired by rural peace and quiet, or lacking anything better to do with his time, the young man thought about science and mathematics. Later he wrote: ‘In those days I was in the prime of my life for invention, and minded mathematics and [natural] philosophy more than at any other time since.’ His researches led him to understand the importance of the inverse square law of gravity, an idea that had been hanging around ineffectually for at least 50 years. He worked out a practical method for solving problems in calculus, another concept that was in the air but had not been formulated in any generality. And he discovered that white sunlight is composed of many different colours – all the colours of the rainbow.
    When the plague died down, he told no one about the discoveries he had made. He returned to Cambridge, took a master’s degree, and became a fellow at Trinity. Elected to the Lucasian Chair of Mathematics, he finally began to publish his ideas and to develop new ones.
    The young man was Isaac Newton. His discoveries created a revolution in science, bringing about a world that Charles II would never have believed could exist: buildings with more than a hundred floors, horseless carriages doing 80 mph along the M6 motorway while the driver listens to music using a magic disc made from a strange glasslike material, heavier-than-air flying machines that cross the Atlantic in six hours, colour pictures that move, and boxes you carry in your pocket that talk to the other side of the world . . .
    Previously, Galileo Galilei, Johannes Kepler, and others had turned up the corner of nature’s rug and seen a few of the wonders concealed beneath it. Now Newton cast the rug aside. Not only did he reveal that the universe has secret patterns, laws of nature; he also provided mathematical tools to express those laws precisely and to deduce their consequences. The system of the world was mathematical; the heart of God’s creation was a soulless clockwork universe.
    The world view of humanity did not suddenly switch from religious to secular. It still has not done so completely, and probably never will. But after Newton published his Philosophiæ Naturalis Principia Mathematica (‘Mathematical Principles of Natural Philosophy’) the ‘System of the World’ – the book’s subtitle – was no longer solely the province of organised religion. Even so, Newton