Newton, page 2
The year 1666 became celebrated as Britain’s annus mirabilis, when the nation’s fleet triumphed over the Dutch, and London survived the Great Fire. Newtonian historians have described 1665–6 as Newton’s personal annus mirabilis when, forced into rural retirement, he compiled a staggering array of new mathematical and scientific techniques. Half a century later, Newton boasted (perhaps a touch wistfully) that ‘in those days I was in the prime of my age for invention & minded Mathematicks & Philosophy more than at any time since’.5
This was when Newton supposedly gained inspiration by watching an apple fall from a tree, and biographers often depict an Arcadian interlude of frenetic and almost overnight creativity. Nevertheless, such tempting tales ignore the long periods Newton dedicated to experimental and theoretical confirmation of his theories. Moreover, some of the dates inconveniently refuse to comply with this simplified picture. Effectively exiled into academic solitary confinement, Newton did not immediately and single-handedly revolutionize the seventeenth-century scientific world with the fruits of his research. However, it is fair to say that he made key discoveries in mathematics, optics and dynamics, which formed the foundation for much of his own subsequent work, and affected the future course of science.
Once back in Cambridge, Newton adopted a solitary life, and spent much of the next two years secretly poring over alchemical manuscripts and experiments. He was shocked out of this seclusion in 1668, when a new book on mathematics forced him into print to establish his own priority, and he was soon appointed the Lucasian Professor of Mathematics. Although Newton was to hold this post for thirty-two years, he was a poor lecturer who often ‘for want of Hearers, read to ye Walls’,6 and he increasingly neglected his teaching duties. Immersed in his research, he was only interested in communicating his ideas to other mathematical experts.
Yet Newton’s first public success was not with a new theory, as his subsequent reputation might lead us to expect, but with a small reflecting telescope that he built himself, even grinding the lenses by hand. Only 15 cm long, Newton’s telescope could magnify distant objects far more powerfully than larger models, and in 1672 he was elected to the Royal Society. In his first lecture, he presented many of the ideas that would overturn not only the science of optics, but also the methodology of scientific practices. Subsequently developed into the Opticks, one of his most famous books (first published in 1704), Newton’s early accounts of his experiments with prisms simultaneously rewrote the nature of light and set theoretical work on a new experimental basis.
Newton described to the Fellows what is often called his crucial experiment, in which he used two prisms to demonstrate that sunlight is composed of coloured rays of light (Figure 1.3). He aimed to reject the prevailing view, which was essentially Descartes’s reworking of Aristotelian ideas, that the colours we see around us occur because white light is modified when it interacts with an object’s surface. Newton argued that different colours are inherently present in sunlight. Conceiving light as streams of tiny particles that are slowed down when they pass through glass, he explained that a prism separates light out into its constituent coloured rays.
In this early work on optics, Newton also laid the basis for his experimental approach, which profoundly affected the ideology of scientific research. The way forward, he insisted, was not to devise abstract hypotheses, but to build theories on the twin pillars of mathematics and experiment. That this does not now seem such a revolutionary suggestion is precisely because Newton’s innovations have become fundamental principles of modern science. But before then, geometry, experimentation and natural philosophy had been three distinct domains on the map of knowledge, traditionally occupied by people with different skills and goals. Henceforth, preached Newton, theories would be the consequence of observations, not their inspiration.
Far from following up on his controversial entrée into the international world of natural philosophy, Newton withdrew into Trinity College and devoted much of the 1670s to pursuing alchemy and theology. He was also absorbed in mathematics, an aspect of his work that tends not to receive much attention, perhaps because people find it difficult. Some of Newton’s conclusions proved extremely influential, particularly the neat formulae he derived for curves and series of algebraic expressions. Another significant innovation, which he called fluxions and we call calculus, has become particularly famous because it led to a bitter priority row between Newton and his arch-enemy, the German mathematical philosopher Gottfried Leibniz. Their successors energetically perpetuated this international dispute for decades, and historians are still finding fresh perspectives from which to analyse it.
At the same time as developing new mathematical techniques, Newton was scouring books and manuscripts to compile information about ancient chronology, religious doctrines and biblical prophecies. Owing to his belief that orthodox interpretations of Christ’s holy status were wrong, Newton received a royal exemption from the normal obligation for Cambridge Fellows of being ordained in the Anglican Church. Convinced that scholarly interpretation could restore the original meaning of corrupted scriptural texts, he also sought to retrieve arcane alchemical knowledge. This was no mundane search for the philosopher’s stone or the elixir of life, but a quest of the soul. Newton believed that a divine vegetative spirit pervades the world and effects material and spiritual transformations, governing changes in metals as well as the growth of plants and animals. Converting a College garden shed into his private alchemical laboratory, he constructed his own furnaces to explore in secret these processes of natural development. Newton continued this research until the mid-1690s, and his published works on gravity and optics – those now seen as the foundation of modern science – are suffused with alchemical and religious concepts.
In the early 1680s, a series of comets blazed across the sky, arousing terrified fascination throughout Europe. Many people interpreted these celestial spectacles as prophetic messages from God, and Newton became obsessively interested in these unpredictable phenomena. Spurred on by discussions and correspondence with his associates, he dedicated himself to mathematical astronomy and started writing his most famous book, the Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy). First published in 1687, and twice revised to accommodate criticisms, the Principia lies at the heart of Newton’s subsequent reputation because it provided a new cosmology.
Even though we may not realize it, we view the universe through Newtonian spectacles. This makes it hard for us to imagine older ideas and take them seriously. Newton was born at a time when traditional views still survived. Some people were still arguing about the displacement of the earth from the centre of the planetary system, and Newton himself was affected by the Aristotelian distinction between the earth, which is constantly in flux, and the unchanging heavens, which rotate in divinely perfect circles.
Conflicting theories had been put forward during the seventeenth century. One influential model was proposed in 1600 by the English physician William Gilbert. In his cosmos, the sun and the planets are bound to each other magnetically (which is why the poet John Milton referred to the sun’s ‘magnetic beam’ in Paradise Lost). It was Gilbert’s magnetic beliefs that directed the research of Johannes Kepler, whose demonstration that planets move in elliptical orbits crucially affected Newton’s own work. Other natural philosophers, most notably Descartes, objected to the idea of an invisible occult force extending its powers as if by magic. Descartes insisted that action depends on contact, so his universe is packed with tiny particles that push against each other and swirl around in patterns called vortices.
The Principia revolutionized the course of physics by providing a single mathematical law to describe the motion of heavenly bodies as well as minute particles of matter on earth. For the first time, natural philosophers could provide reliable forecasts of when a comet would reappear. This helped them to claim that their approach to the world was superior to astrological or biblical predictions, and thus to wrest authority from traditional experts. That a complete manuscript ever reached the press was largely due to the persistent persuasion of Edmond Halley. Although then merely the paid Clerk of the Royal Society, Halley later became famous in his own right as the Astronomer Royal who correctly forecast the return of the 1682 comet that now bears his name. For Newton also, this research into comets lay at the heart of his subsequent fame.
Written in Latin and packed with geometrical diagrams, the Principia appears a dry book, but for those who understood it, Newton wrote in a persuasive style. Right at the beginning, he stated his three laws of motion, which govern how objects move and interact with one another. Most people first encounter these laws at school, when asked to solve problems about colliding billiard balls, or lorries rolling down hills. Newton’s great coup was to apply these laws to describe the motion of the planets, thus uniting events on earth with motion in the heavens. He introduced a new concept of gravity, picturing a universal attractive force stretching out through space, one which affected comets, falling apples and tiny atoms in the same way. Unlike Descartes, Newton visualized large tracts of empty space not only between the heavenly bodies, but also between the particles that make up apparently solid matter.
Just as importantly, Newton expressed gravity’s effects mathematically. The nearer to one another two objects are, and the heavier, the more strongly they attract each other. This is known as the inverse square law, because this attractive force depends on the square of the distance between the objects. While Albert Einstein is celebrated for the equation e=mc2, so Newton’s work is symbolized by the 1/r2 relationship.
Newton’s book also abruptly altered the pattern of his own existence. In addition to the deluge of congratulations, criticisms and controversies, other events were forcing Newton to reappraise his life. In particular, with the departure of his friend Fatio de Duillier, a young Swiss mathematician, the only close adult relationship he ever formed came to an end. A few weeks later, in the autumn of 1693, after he started sending bizarre letters to his colleagues, rumours circulated that he had gone mad or even had died. Becoming even more reclusive, Newton turned in on himself, continuing his alchemical experiments and revising his manuscripts.
In 1696, Newton emerged from this self-imposed seclusion and embarked on a totally new career at the Mint. Enjoying metropolitan prominence, he became England’s most celebrated and powerful natural philosopher. As Warden and later Master of the Mint, he pursued his duties with an intensity matching his previous devotion to alchemy, theology and mathematical astronomy. He instituted major reforms, and zealously persecuted fraudulent money-makers – even to the extent of arranging their executions.
Elected President of the Royal Society in 1703, Newton became an authoritarian patron and administrator, ensuring that his influence and his ideas extended throughout Europe. The following year he published the first edition of the Opticks. Although its ideas were no longer controversial, this book comprised a manifesto presenting his mathematical, experimental style of research. As successive editions appeared, Newton added an increasing number of speculations about fundamental topics such as the nature of matter and its relation to life. Disguised as ‘Quæries’, these ingenuously phrased speculations often contradicted his earlier ideas, and formed the experimental agenda for his eighteenth-century successors. Responding to critics, Newton also revised the Principia, in 1713 adding an appendix (called the General Scholium) that emphasized God’s constant presence throughout the universe. As before, theology and natural philosophy were inextricably linked together.
From his knighthood in 1705 through to his death in 1727, Newton continued working at the Mint. At the same time, he was actively involved in the international community of natural philosophers, rewriting and publishing earlier work in mathematics, optics and astronomy, and supervising his vicious priority dispute with Leibniz. But in private, his major concern was to consolidate his previous theological studies. Juggling with dates to reconcile conflicting events and opinions, Newton endlessly revised his manuscripts on ancient chronology and biblical prophecy. Shortly after he died, sanitized versions that effectively concealed his heretical religious ideas were published. His heirs had already put into motion the machinery designed to protect and enhance his reputation.
A secular saint
Like William Shakespeare, England’s other most exalted genius, Newton’s reputation has been repeatedly refashioned.7 Indeed, it is precisely because his life has been constantly reinterpreted that we can examine how he became converted into a national scientific hero. Even such a basic fact as his date of birth is unclear. England was then ten days out of step with most of the rest of Europe. Ironically, Newton would himself urge the government to reform the English calendar, but it was not until 1752 that the country belatedly moved out of its self-imposed isolationism. So although Newton was born on Christmas Day 1642 in England, in France and other European countries it was already 4 January 1643.8
Different types of uncertainty shroud other aspects of Newton’s life. Although it is common knowledge that he watched an apple fall from a tree, historians continue to argue about the significance of this celebrated event and indeed whether it occurred at all. We remain uncertain about his appearance, since contemporary descriptions and portraits give conflicting pictures. Was he a thin, prematurely grey scholarly type with a piercing gaze (as in Figure 2.1), or was he a plump, brown-haired man with a distant demeanour (Figure 2.2)? Looking back, other large question-marks hang over his life. Did he experience a period of insanity from which he never fully recovered – and if so, was this an inherited problem, or one brought on by overwork or experimenting with dangerous chemicals? Did he turn a blind eye to his niece’s clandestine love affair in order to gain his powerful post at the Mint? And what about his own love life – did he renounce romance for science, did he enjoy homosexual relations with younger men, or was he emotionally damaged by his father’s death before he was born and by his mother’s remarriage when he was three years old?
Over the last 300 years, Newton’s biographers have argued about the answers to these and many other questions. They have disagreed about his major achievements, and what significance he attached to different aspects of his work. Were his alchemical ideas central to his cosmological theories, or were they the embarrassing delusions of an otherwise supremely rational intellectual? Should we regard his long years at the Mint as the patriotic duty of a dedicated administrator, or the government’s exploitation of an underpaid academic? Do his theological books comprise the sad ramblings of an elderly man, or do they confirm a lifelong religious commitment?
Although researchers are still uncovering new details, examining such issues is made more difficult by the absence of manuscripts that have been destroyed over the years by enthusiasts eager to preserve Newton’s public reputation. Still more importantly, all Newton’s biographers have selected from the vast corpus of available information only what they feel to be relevant facts. They have disagreed not only over what these facts are, but which ones are significant. There are several reasons for these differences in approach. Partly they reflect trends in historical fashion. Compared with the Victorians, for instance, modern writers are more inclined to integrate a famous subject’s personal and public lives, and to show how emotional and social experiences are inseparable from achievements, whether these be scientific discoveries, military victories or philosophical inquiries. Furthermore, writers obviously tailor their descriptions of Newton to suit their readers. Thus one might expect (not always accurately, as it turns out) an entry in a children’s encyclopaedia to include more information about Newton’s own childhood than the introduction to a scientific textbook.
But changes in Newtonian biography also reveal more specific transformations. Understanding how Newton has become a cultural icon entails not just studying Newton himself, but also examining how society’s attitudes towards science, famous people and fame itself have changed during the last 300 years. Authors have created various versions of Newton’s life because they have held different views of what it means to be a successful person. There is no simple one-way relationship between what society at large judges to be the characteristics of greatness, and the biographical accounts that are produced. These biographies themselves help to formulate who is famous and how famous people are defined. Thus the shifts in Newton’s reputation have simultaneously mirrored and moulded broader social perceptions.
None of Newton’s contemporaries shared our view of him as a ‘scientific genius’, because that concept had not yet been invented. Countless representations of Newton have themselves contributed to our understanding of what the terms science and genius mean. The past is often said to be a foreign country, and words such as science and genius are deceptive, because their meanings have repeatedly altered.9 In Newton’s time science meant something resembling systematic knowledge, so that although Newton’s experimental colleagues were called natural philosophers, only some aspects of their activities came to form the antecedents of modern science. Natural philosophy was an umbrella term embracing different practices, but its major objective was to learn more about God through studying the natural world. In a widely used phrase coined by the chemist Robert Boyle, one of Newton’s associates at the Royal Society, these new ‘priests of nature’ read and interpreted the divine book of the natural world rather than God’s other great book, the Bible.
The wealthy gentlemen who studied and experimented in the privacy of their own homes or university studies fervently believed in the value of their research, but they enjoyed little public interest or government support: indeed, they were often viciously caricaturized. Among the frequent satires that mocked the pretensions of gentlemanly collectors and opportunistic inventors, the most famous example is now Jonathan Swift’s Gulliver’s Travels, first published in 1726. Swift parodied the Royal Society as the Academy of Lagado, staffed by bumbling professors turning the cranks of unworkable language machines, and frequented by unrealistic schemers trying to make cucumbers out of sunbeams.
