Peter Harrison reviews Rob Iliffe’s Priest of Nature The Religious Worlds of Isaac Newton.

When Isaac Newton died on March 31, 1727, his estate included a massive amount of unpublished material. Almost 2000 short manuscripts, haphazardly housed in numerous boxes, bore testimony to the extraordinary range of Newton’s interests. Along with the expected jottings on scientific and mathematical topics was a surprising number of items devoted to alchemy. But the vast bulk of this material, well over two million words, was devoted to religious themes—chronology, prophecy, the apocalypse, and the history of early religion and of the Christian church.

Rob Iliffe, who holds the chair in History of Science at the University of Oxford, has an unmatched mastery of this manuscript material. For almost twenty years he has led the team behind “The Newton Project,” a visionary enterprise devoted to the online publication of the complete corpus of Isaac Newton’s papers. For this alone we owe him and his fellow researchers an enormous debt of gratitude. But Priest of Nature gives us cause to be doubly grateful. This meaty volume represents the first fruits of these assiduous editorial endeavors and it presents what is surely the definitive account of Newton’s religious world view. It is a remarkable work of painstaking scholarship, engagingly written, and packed with new insights into the man and his milieu.

That Newton’s theological writings have now seen the light of day at all is a story in its own right. After Newton died intestate, Thomas Pellet was charged by the Royal Society with assisting his executors in determining what material should be published. A number of the manuscripts still bear his scribbled verdict: “not fit to be printed.” In a sense, this adverse finding was repeatedly rendered on Newton’s unpublished theological writings, virtually to the end of the twentieth century.

A number of factors conspired against the publication of Newton’s private theological writings. In the eighteenth century Newton had become an icon of Enlightenment philosophes and his scientific achievements were regarded by them as emblematic of scientific rationality. Newton’s deep personal piety and preoccupation with matters of biblical chronology and prophecy, had they become widely known, would have challenged Enlightenment assumptions about a necessary opposition between religion and science. Subsequently, his religious views (or at least what was known of them) came to be regarded as an embarrassment or, at best, irrelevant to his reputation and achievements.

On the other side, those who wished to perpetuate the image of Newton as a godly scientist had to reckon with the fact that his unpublished writings exhibited unmistakable evidence of deeply heretical views. Newton was never able to reconcile himself to the idea that Christ was truly divine and part of the triune godhead. On the basis of his methodical biblical and historical researches he had arrived at the view that the doctrine of the Trinity was a corruption of true Christianity. Newton had been careful to conceal his position from his contemporaries, and with good reason. Public knowledge of his private beliefs would have had catastrophic consequences for his career. The first custodians of his literary estate, Newton’s half-niece and housekeeper Catherine, and her husband John Conduitt, who succeeded Newton as Master of the Mint, were understandably concerned to preserve Newton’s reputation, not just as a man of science, but as an exemplary Christian. Accordingly, they were disinclined to see his heterodox views made public.

Newton’s scientific papers eventually found their way into the Cambridge University Library in the late nineteenth century. The bulk of the alchemical and theological writings, however, did not make a public appearance until 1936 when, for financial reasons, their owner put them up for auction at Sotheby’s. They attracted little interest, and no institutional bidders sought to acquire them. Belatedly, two individuals—the economist John Maynard Keynes and biblical scholar, philologist, and collector, Abraham Yahuda—realised the value of this material and ensured that it was not completely dispersed among private collectors. Through their good offices the manuscripts were lodged in libraries in Cambridge and Jerusalem. Over the past fifteen years these documents, brought together with other miscellaneous manuscripts, have been dated, collated, transcribed, translated where necessary, and published online with editorial commentary. They have yielded a mine of information about Newton’s religious views and his methods of historical investigation. (The full story of the fate of Newton’s manuscripts is recounted in fascinating detail in Sarah Dry’s 2014 book, The Newton Papers.)

Rumours had circulated about Newton’s heterodox Trinitarian views even in his own day, and his alchemical, chronological and historical interests have long been known to historians. But access to the complete, edited archive has meant that Iliffe’s work easily surpasses previous scholarship on these matters, offering the most authoritative and comprehensive account of Newton’s religious world thus far available. We learn not only that he held heterodox theological views, but how, through a combination of textual and historical criticism, he arrived at them. We also get to understand how Newton’s subscription to two fundamental Protestant principles—a deep suspicion of idolatry and a commitment to the primacy of scripture—formed his theological thinking.

Newton’s doubts about the Trinity were not fueled, as for some of his contemporaries, by a rejection of revealed truths and a deistic demand for a rational conception of God. For Newton it was simply that he could not find the Trinity in scripture—for him the supreme authority. His textual and historical investigations, moreover, showed how this “idolatrous” conception came to be incorporated into Christianity. We also discover that in spite of the obvious strength of his religious convictions, Newton was an advocate of toleration and religious freedom. Genuine religion he regarded as less a matter of correct belief than of right living and personal piety.

Along with much detail on Newton’s chronological calculations, Iliffe provides us with glimpses of Newton’s intriguing speculations about the post-millennial world and the conditions that would bring it about. While Newton had initially believed that the final conflagration, prophesied in the Second Epistle of Peter, referred to political and religious upheavals, he was later to speculate about possible physical events that might precipitate the end of the present world. Comets, with their eccentric orbits, afforded one possible mechanism. Newton thought it possible that the Great Comet of 1680, on one of its return journeys—possibly in five or six revolutions—might collide with the sun, leading to the incineration of the earth and its inhabitants. As for the post-millennial world, it would be populated by innumerable creatures, some of which would have natures that were beyond human ken. Other beings in the future state would have the capacity to move through space at will. The abode of faithful, the “New Jerusalem,” would be shaped like a cube, and extend from earth to the heavens.

The materials that Iliffe has worked with also help round out our portrait of Newton the person. For some of his contemporaries, Newton had an air of sanctity: he was a possessed of “quiet and meek spirit”; he was a “white soul”; his powers verged on the superhuman; had he lived in a Catholic country he would have been a candidate for canonization. But in truth Newton could be a difficult person. Even his close friends allowed that he was “prodigiously fearful” with a “suspicious temper” that could border on paranoia. On occasion he also behaved unconscionably in order to give his own work priority over that of others.

While Iliffe has revealed for the first time the full range and content of Newton’s religious interests, those with an inkling of his theological views have long wondered whether there is a hidden harmony to his thinking—a way of integrating the diverse and apparently contradictory aspects of the great man’s thought. Iliffe’s researches make this question even more acute: what connection, if any, is there between the celebrated scientific accomplishments and the massive body of lesser known writings on alchemy, theology, history, and biblical chronology?

One long-standing thesis is that there is radical discontinuity—opposition even—between Newton’s religious proclivities and scientific achievements. His nineteenth-century French biographer Jean-Baptiste Biot offered one explanation of this apparent cognitive dissonance. Newton, he contended, had experienced a mental breakdown in 1692, just after the completion of his scientific masterpiece, the Principia. The life of the great man could thus be neatly divided into two halves. During the first half, he gave full reign to his scientific genius, making all the major discoveries upon which his subsequent fame rested. During the latter period of his life, however, his mental powers deserted him and unhappily he degenerated into a religiously obsessed crackpot. This was the period of his alchemical and theological preoccupations.

It is certainly true that Newton underwent something of a crisis during this period. In September 1693, Newton’s friend, the diarist Samuel Pepys, expressed concern for the great man’s mental condition, writing of his “discomposure in head, or mind, or both.” Newton himself admitted at this time that he had lost “his former consistency of mind” and had gone for many weeks with virtually no sleep. As Iliffe conclusively demonstrates, however, the thesis of a descent into dotage is a poor explanation of how Newton could have been preoccupied with topics that to the modern mind are so disparate. In fact, Newton had engaged in religious and historical investigations from the very start, and the periods of scientific creativity overlap substantially with his theological and chronological investigations. Whatever mental crisis he underwent in the 1690s, it seems to have been relatively short lived.

By the same token, those who seek a unitary method or conceptual key to understanding the connections between Newton’s diverse writings are likely to be disappointed. Iliffe cautions against the idea that there is a simple conceptual or methodological coherence to Newton’s oeuvre. Thus, “the vast bulk of his writings on church history and prophecy emerged from a parallel intellectual universe to that of his natural philosophy.” Newton was not in possession of a single hermeneutical method that could be applied indiscriminately to sacred texts and to the great book of the universe.

It does not follow, of course, that Newton’s religious beliefs had no bearing on his science. On the contrary, Newton freely admitted that when he wrote the Principia he had in mind the promotion of belief in the Deity among “considering men.” He also maintained the conventional line that the arrangement of the solar system bore witness to God’s wisdom and power, and, more particularly, that various features of the cosmos had been “fine tuned,” as we would now say, to the advantage of its human inhabitants. In relation to his own gravitational theory Newton was conscious that the stability of the solar system was threatened by the cumulative mutual attractions of the planetary bodies and comets, and he believed that divine intervention would be necessary to keep things on track. And as we have seen, the orbit of comets could be pressed into the service of his biblical eschatology.

More generally, Newton may be regarded as a reformer who saw himself entrusted with a mission to recover a philosophy of nature that had been known to the ancients but which, like Christianity, had been subjected to a long history of corruption. For him, both Christianity and science needed to be restored to their primitive simplicity. While these dual reform tasks may have demanded different methods, there lay behind them a unity of purpose. There was a single-minded moral seriousness that drove Newton’s investigations, whatever their object.

Iliffe’s meticulous scholarship has added an important new dimension to our understanding of Newton, one that restores religious concerns to a central place in the biography of this fascinating figure. To see Newton’s religious interests as marginal to his remarkable accomplishments, tempting as it may be, is to project the priorities of our own era onto his. As Iliffe puts it, Newton’s theological papers represent “the concerted efforts of the greatest thinker of his age to engage with the biggest questions of his time”—a timely reminder that sometimes the biggest questions are not ones that science can answer.

Peter Harrison is an Australian Laureate Fellow and Director of the Institute for Advanced Studies in the Humanities at the University of Queensland. He is author of The Territories of Science and Religion.