The life of Isaac Newton falls into two halves, and the main problem for Newton studies is how to fit them together. In the first half he was a sulky Cambridge mathematician who, at the age of 44, astonished the world with a work of natural science that was soon recognised as one of the greatest books ever written. In the second he was a sleek London gentleman wallowing in power, wealth and prestige and devoting his intellectual energy to esoteric studies of the Bible. How could they be the same person?

Newton’s first biographer, Jean-Baptiste Biot, proposed the classic solution in 1822: Newton was ‘the greatest of mankind in science’, Biot said, until the midpoint of his life, when he suffered a ‘fatal aberration of his intellect’, started dabbling in theology, and ‘ceased to think of science’. That was how the matter was left until 1936, when a stash of Newton’s papers turned up at a London auction house, providing clear evidence that the great scientist had been a fanatical biblicist all along. Maynard Keynes, who rescued many of the documents from the sale, concluded that Newton could not have ceased to be a scientist, because he had never been one in the first place. He was not the ‘first of the age of reason’, Keynes said, but ‘the last of the magicians’: not a modern scientist treating the world as a collection of impersonal facts, but an old-style magus for whom it was a ‘riddle’ propounded by a teasing God. Since Keynes’s time, however, we’ve come to accept that irrationality can have a part to play in the growth of science, and the exuberant new book by Jed Buchwald and Mordechai Feingold raises the stakes by arguing that Newton’s biblical lucubrations are just as scientific as his theory of gravitation, and scientific in much the same way.

One thing everyone can agree on is that Newton’s mind was shaped by his miserable childhood. He was born in 1642, into a prosperous farming family in Lincolnshire, but his father was already dead, and his mother had other things on her mind besides her son. Young Isaac found consolation wherever he could: he dreamed of killing his mother, and burning the house down around her, and he took revenge on the other boys at Grantham grammar school by doing better at lessons than them. His mother wanted him to become a farmer, but he defied her by getting a scholarship to Trinity College, Cambridge at the age of 18. He remained surly and solitary throughout his four undergraduate years, and insisted on reading modern authors like Descartes rather than the Aristotelians he was supposed to be studying. He was befriended by an enlightened professor of mathematics, Isaac Barrow, but showed no signs of intellectual distinction, and when the university was closed in 1665 – on account of the Great Plague – he had no choice but to slink back to his mother’s house. He was still refusing to take any interest in farming, and devoted his next two years to making notes on everything he saw and messing around with glass prisms in darkened rooms.

By that time he had settled into a steady habit of suspicion: he trusted nobody, and refused to believe anything that he couldn’t reduce to mathematical terms and prove for himself from first principles. In particular, he trained himself to doubt the evidence of sensory experience: sensible qualities were events in our bodies rather than features of the objective world, and sense organs, like any other mechanical instruments, were liable to bias, inconsistency and malfunction. He stared at the sun to give himself delusive after-images, and manipulated his eyeballs with a brass skewer. ‘I tooke a bodkine,’ he wrote in his notebook, ‘& put it betwixt my eye & bone as neare to [the] backside of my eye as I could: pressing my eye [with the] end of it … there appeared severall white & darke & coloured circles … which circles were plainest when I continued to rub my eye [with the] point of [the] bodkine.’ After many months with his bodkins, notebooks and prisms he came to the conclusion that our eyes can deceive us even about something as obvious as daylight, which appears plain and simple to us, but is in fact composed of lights of many different colours. Appearances can conceal as much as they reveal.

When the university reopened in 1667, Newton returned to Trinity, with Barrow as his mentor and protector. He became a college fellow, took his MA, and started using a wooden building behind the chapel as a laboratory, conducting chemical experiments and building a telescope to a new design based on curved mirrors instead of lenses. He was still averse to public attention, but Barrow was impressed by his talents and arranged for Newton to succeed him when he retired from his chair in 1669. The nervous young professor was required to give lectures, but chose to focus on optics rather than mathematics, and wasn’t disappointed if attendance was sparse. Meanwhile, his fame was beginning to spread in spite of himself. He gave Barrow permission to take the reflecting telescope to London for a demonstration at the Royal Society, which brought him unwanted acclaim and election to a fellowship in 1672. He wasn’t prepared to attend meetings of the society, but submitted a communication in which, as he put it, ‘light is declared to be not Similar or Homogeneal … and Colours are affirm’d to be not Qualifications of Light.’ The paradoxical paper was printed in the Royal Society’s Transactions, provoking a controversy which confirmed him in his horror of publicity.

For the next decade Newton stayed in Cambridge, working privately on an ambitious theoretical programme, in two parts: first, to reduce the ‘phenomena of motions’ to hidden ‘powers’ or ‘forces’ acting according to ‘mathematical principles’, and second, to apply these principles to astronomy so as to ‘deduce the motions of the heavens a priori’ and vindicate a heliocentric system of the world. In 1684, he received a visit from the young astronomer and explorer Edmond Halley, who was astonished at how much he had achieved. Eventually Newton was persuaded that his results should be published, though it took him three anguished years to get them into a form with which he was satisfied. His principal discoveries – the three laws of motion and the explanation of gravity and planetary motion in terms of universal attraction – were simple and elegant and easy to understand, and one of his early drafts was written methodo populari, as he put it, to ensure that it ‘could be widely read’. But then he had second thoughts, and the final version was presented more Mathematico – in lifeless Latin, purged of specific observations, metaphors and anecdotes, and with thickets of definitions, axioms, corollaries, lemmata, propositions and theorems to keep frivolous amateurs at bay.

Halley covered the printing costs, and wrote a prefatory ode hailing Newton as ‘closer to the gods’ than any other mortal. The book itself – a large quarto volume of five hundred pages entitled Philosophiae Naturalis Principia Mathematica – appeared in 1687, with the imprimatur of the Royal Society, and the edition of around three hundred copies sold fast. But its sales were nothing compared with its burgeoning fame. Halley’s idea of him as a man with special access to the mind of God became a commonplace.

Following the publication of the Principia Newton began to refashion himself as a public figure. When the provostship of King’s College fell vacant in 1689, he campaigned to get himself appointed, and was indignant when he failed. But he succeeded in getting elected as MP for Cambridge University, and soon developed a taste for politics and power. In 1696, he moved to London to take charge of the Royal Mint: a serious job, which involved overseeing a vast programme of recoinage, pursuing cheats and counterfeiters and earning enormous sums of money. In 1703 he became president of the Royal Society too. In both these offices he would fulfil his obligations with zeal and efficiency until his death in 1727, at the age of 84.

During his London years, Newton set about dismantling some of the barriers he had placed between himself and his public. Opticks, which came out in 1704, was as substantial in its way as the Principia – its principal arguments had been in place for thirty years – but it was written in pleasant English, with plenty of explanations, remarks and outlines of practical experiments, rounded off with a set of ‘queries’ that might form suitable topics for polite conversation. ‘May not the harmony and discord of Colours arise from the proportions of the vibrations propagated through the fibres of the optick Nerves,’ he asked winningly, ‘as the harmony and discord of sounds arise from the proportions of the vibrations of the Air?’

Apart from trying to please his readers, Sir Isaac – as he became in 1705 – also sought to reassure them about his theological opinions. He was known to have ducked out of ordination in the Church of England, which was formally a condition of his professorship, and his reputation as a divine genius had a whiff of blasphemy about it. He had avoided any discussion of God or creation in the Principia (in the first edition, that is, where God is mentioned only once), and could not pretend to be interested in priests, rituals or religious ceremonies. On top of that there were well-founded rumours that he regarded the doctrine of the Trinity as a papist fabrication. But if his version of orthodoxy differed from that of the established church, there could be no doubt about his reverence for the Bible. To anyone wondering about the truest form of Christian worship, his advice was clear: ‘search the scriptures thy self,’ he said, with ‘constant meditation upon what thou readest, & earnest prayer to God to enlighten thine understanding’. He was convinced the Bible was, essentially, a sacred text, and he sought to honour his maker by studying it closely, every day, sometimes for hours on end. He read it repeatedly, in English, Latin, Greek and Hebrew, weighing every word, syllable and letter. ‘Mr Newton is really a very valuable man,’ as John Locke put it, ‘not onely for his wonderfull skill in Mathematicks but in divinity too & his great knowledge in the scriptures where in I know few his equals.’

Newton read the Bible with the same exactness he brought to his mathematical inventions or his experiments with prisms, and with the same disregard for tradition and common sense: he always refused, as one critic put it, to acknowledge ‘any one’s having ever consider’d the same Things before him’. He fled from controversy in religion as he did in mathematics, but he was convinced that his discoveries in the two domains supported each other, maintaining that the leading doctrines of the Principia – heliocentrism and universal gravitation – had formed part of the primitive biblical religion from which all others derived, and were explicitly endorsed by Moses before being passed to the Greeks and winning general assent in ‘the earliest ages of philosophy’. Mathematics could thus unite with the biblical narrative to proclaim the reasonableness of Christianity.

Newton produced a revised edition of Principia in 1713, adding a scholium generale in which he argued that the solar system in all its beauty ‘could only proceed from the counsel and dominion of an intelligent and powerful Being’ – not a passive and impersonal ‘soul of the world’, but a domineering potentate and ‘Lord over all’. He extended his list of ‘Queries’ as the Opticks went into further editions, noting a ‘wonderful Uniformity’ in the bodies of animals and the system of stars, and suggesting that it must be ‘the Effect of Choice’, and testimony to the ‘Wisdom and Skill of a powerful ever-living Agent’. If the heathens who flourished in the millennium before Christ had only stuck with primitive religion instead of chasing after ‘false Gods’ they would never have ceased to ‘worship our true Author and Benefactor, as their Ancestors did under the Government of Noah and his Sons before they corrupted themselves’.

In 1717, when he was well into his seventies, Newton was summoned to meet Caroline, Princess of Wales, who wanted to know how his biblical researches were progressing. When she realised that he had worked out a comprehensive new chronology of the ancient world, based on the Bible, she persuaded him to prepare a summary for her. Before long an unauthorised copy turned up in Paris, where anything connected with ‘le chevalier Newton’ was greeted with excitement, often seasoned with envy. ‘They say that Newton’s celebrated chronology … is destined to bring marvellous changes to the science of time,’ as one wit put it: ‘otherwise, why would the great mathematician have spent so many years working on it?’ To cast light on the question, a Parisian printer commissioned a translation of the pirated abstract and published it as a pamphlet in 1725, along with a detailed confutation. Newton was incensed, and decided to prepare a full account of his work for publication. He died two years later, and after his spectacular funeral at Westminster Abbey the still incomplete manuscript was found among his papers. It was sold for the huge sum of £350, and printed soon afterwards as The Chronology of Ancient Kingdoms Amended.

With the publication of the Chronology, the divine Newton at last entered terrain where common readers felt entitled to their own opinions. Anyone who reads through the Old Testament is bound to consider totting up the lifespans of the patriarchs and the reigns of the kings in the hope of arriving at a consolidated biblical dateline. In the second century AD, Jewish scholars had reckoned some four thousand years back to the date of creation: to be precise, they placed it at what we would call 3760 BC or, by the less parochial system of dating known as Anno Mundi, they could say that Christ was born in 3760 AM. The early Christians couldn’t agree: they put their trust in the Greek translation of the Bible (the Septuagint), which added around a hundred years to the age at which the patriarchs begat their offspring, moving creation back to around 5500 BC. In the eighth century, the Venerable Bede returned to the Hebrew text and argued that the date should be brought forward again, to 3952 BC. The proposal got him into trouble at the time, but the later date began to prevail in the 16th century, with Luther, Melanchthon, Scaliger and Kepler all coming up with similar estimates, until Archbishop Ussher settled the controversy in 1650 with an authoritative proposal of 4004 BC.

This was the field in which Newton hoped to make his last great contribution to human knowledge. He accepted Ussher’s chronology, but wanted to extend it from the Jews to the Gentile nations. Greek and Roman history had never been satisfactorily synchronised with the biblical narrative, and the problem had sharpened in 1655, when the French theologian Isaac La Peyrère published his Prae-Adamitae, alleging that the annals of other civilisations, including the American and the Chinese, went back far beyond the creation of Adam around 4000 BC. It followed, according to La Peyrère, that these nations had been created separately, long before the Jews, and that they had been spared devastation in the great flood. La Peyrère believed that his doctrine was thoroughly biblical, and entirely compatible with Christianity, but Newton would have none of it. ‘All nations,’ he claimed, ‘have been prone to raise their Antiquities’ – in other words, to overstate their age. The Chaldeans were the worst, pretending that their civilisation went back 473 millennia, followed by the Egyptians, who stuffed their chronicles with ‘feigned Kings, who had done nothing’ in order to claim a pedigree of more than 11,000 years. The Greeks and Romans were much better, but both exaggerated by several hundred years. The Jews were a solitary exception: their bible, in the original Hebrew version, was an honest narrative of their past, and Newton undertook to show that the whole of ancient history could be fitted into the Jewish framework. The universality of the flood would thus be restored, together with a common ancestry for the whole of humanity, going back through Noah and his wife to Adam and Eve.

After the flood, according to Newton, the remnants of humanity had ‘lived together in Chaldea under the government of Noah and his sons’. They remained of ‘one language, one society, and one religion’ for about 250 years, and held themselves to ‘the two great commandments, of loving the Lord our God with all our heart and soul and mind, and our neighbour as ourselves’. (‘This is the primitive religion of both Jews and Christians,’ Newton remarked, ‘and ought to be the standing religion of all nations.’) They bred with gusto, as they had to in order to repopulate the earth, and prospered mightily until they succumbed to the folly of Babel around 1860 BC. At that point they split into several nations, each of which spent the next eight centuries progressing through pastoral and agricultural forms of life until they started building towns and linking them up into kingdoms and empires subject to the rule of judges and kings, thus by gradations arriving at the state of civilisation.

Civilisation as such, according to Newton, had its beginnings about 1125 BC among the Egyptians, followed by the Jews under King David in 1059, and then the Assyrians, Babylonians, Medes and Persians (and no doubt the Chinese and the Americans too, though Newton didn’t mention them). But the main focus of Newton’s efforts was the Greeks. He dated the beginning of their entry into civilisation to the time of Daedalus, who invented ‘the saw, the turning-lath, the wimble, the chip-ax and other instruments of Carpenters and Joyners’ in 989 BC. The oracles got under way a couple of years later, and then Theseus killed the Minotaur and became king, before sending Jason and his Argonauts on an embassy to Egypt in 937. The Trojan War took place in the decade between 905 and 895 – far later than usually supposed – and Dido founded Carthage in 883, where Aeneas showed up shortly afterwards.

Newton’s Chronology elicited dozens of hasty reactions, in France as well as England, but within a year or two it had won acceptance as a worthy sequel to the Principia and the Opticks. The critics found it hard, as Voltaire observed, to ‘allow one and the same Man the Glory of having improv’d natural Philosophy, Geometry and History’, but the fact was that Newton’s revised chronology displayed the same ‘creative Genius’ as the rest of his researches, and the same capacity to ‘unravel and disintangle Chaos’. Diderot agreed, though on different grounds: ‘I prefer Newton’s chronology,’ he wrote, ‘because, if he has calculated accurately, it makes Aeneas the contemporary of Dido,’ thus saving the world’s greatest love story from the charge of anachronism. Gibbon too was enchanted by Newton’s reasoning: ‘His system of chronology alone suffices to ensure him immortality,’ he wrote, and he too approved of the way it allowed for Dido to get her heart broken. After Gibbon, however, Newton’s work as a historian fell into a long oblivion, from which Frank Manuel rescued it in the 1960s; but his elegant study, Isaac Newton: Historian, has now been dwarfed by the labours of Buchwald and Feingold.

Not that they hold the Chronology in much affection: the book to which they have dedicated many years of their lives is, in their opinion, ‘stupefyingly tedious’. On the other hand, they argue, quite persuasively, that it may be the source of one of the formative ideas of our time: that every society must pass through the same stages – savagery, pastoralism and agriculture – on the way to civilised maturity. But their main concern is to demonstrate parallels between the intellectual methods of the Chronology and those of Newton’s contributions to natural science. Newton questioned the evidence of his historical sources, they say, just as he questioned the evidence of the senses, subjecting it to a characteristic blend of experimental manipulation and mathematical synthesis. When it came to estimating the lengths of reigns and generations in antiquity, he used the technique he had pioneered in making physical measurements: compensating for the lack of any single reliable number by juggling discrepant ones, and arriving at various kinds of averages to fill the gap.

Their favourite exhibit is a passage where Newton referred to Clement of Alexandria, who wrote in the second century about the ‘asterisms’ or star patterns associated with someone called Chiron – presumed to be Chiron the Centaur, who nurtured Jason the Argonaut. ‘Now Chiron delineated the asterisms,’ Newton wrote, ‘as … Clemens Alexandrinus informs us: for Chiron was a practical astronomer.’ Newton concluded that the star map passed down by the classical Greeks was originally devised by Chiron to help the Argonauts navigate the Mediterranean. But Newton and his contemporaries knew – as the early Greeks did not – that star maps suffer from built-in obsolescence, because the entire sphere of the heavens, as it appears to an earthbound observer, moves one degree westward every 72 years. Newton could therefore calculate the original date of the Greek map as 936 BC, which gave him a date for the Argonauts setting out to sea.

Newton spent a few paragraphs on the argument, Voltaire expatiated on it for a few more, but Buchwald and Feingold give it more than a hundred dense and delightful pages, at the end of which the reader is likely to agree that Newton applied all his scientific ingenuity to his chronology. His skill with texts, on the other hand, looks rather questionable. ‘Greek Antiquities are full of Poetical Fictions,’ he wrote, ‘because the Greeks wrote nothing in Prose, before the Conquest of Asia by Cyrus the Persian’ – in other words, before the sixth century BC. But Newton’s notion of poetic fictions was bizarre: he assumed that, rather like optical illusions, they must have some palpable reality behind them. For him, the gods and heroes of the pagan nations – from Zeus and Hera to Dido and Aeneas – were historical heroes and heroines: ‘Deified Kings and Princes’, as he put it, or Queens and Princesses for that matter, rather than figments of sheer fancy. Ceres, he explained, was a fine lady who sailed from Sicily to Greece in 1030 BC, and taught the natives to cultivate corn – ‘for which Benefaction,’ Newton says, ‘she was Deified after death.’ In the following generation we might note the clean-limbed Apollo, whose admirers included ‘some singing women, called the Muses’, and then Hercules, who rescued Prometheus in 937 BC, and Ulysses, who escaped from Calypso in 896 BC; and if we notice some inconsistencies in Newton’s numbers, we ought perhaps to regard them as a reflection of the difficult conditions under which the scientific historian has to operate. Or we might say that one of the most inventive scientists in history was obtuse and literal-minded, and incapable of appreciating the power of imagination.