The Faith of a Great Scientist: Robert Boyle’s Religious Life, Attitudes, and Vocation

Over the past several months, I’ve introduced readers to John Polkinghorne, a leading modern scientist who is also an outspoken Christian. This new series will introduce you to a great scientist from the period often called the “Scientific Revolution,” when modern science came into existence. The English chemist Robert Boyle (1627-1691) is an outstanding example of a Christian scientist whose faith interacted fundamentally with his science. His remarkable piety was closely linked with his interest in science, and his Christian character shaped the ways in which he conducted his scientific life. A deep love for scripture, coupled (ironically) with a lifelong struggle with religious doubt, led him to write several important books relating scientific and religious knowledge. We’ll explore aspects of this fascinating interaction over the next few months. I hope you’ll join us for the conversation.

Who Was Robert Boyle?

Robert Boyle is best known today as the person who published “Boyle’s Law,” the inverse relation between the pressure and volume of gases that is a standard part of a basic chemistry course. Often this is shown graphically as in this illustration,  but Boyle didn’t present it in that way, nor did he write it down as an equation, such as PV = k, where P and V are the pressure and volume of the gas and k is a constant numerical value.

Boyle didn’t usually think in abstract mathematical terms. Rather, he thought concretely about specific measurements and how to make them as accurately and precisely as possible. Thus, he presented the relationship simply by giving a table of measured values for the pressure and volume of a small sample of air that he trapped under a column of mercury in a glass tube.

This was a major scientific discovery, but he did much more. Over a period of more than three decades, Boyle wrote extensively about various properties of matter in all three of its basic phases—liquid, solid, and gaseous. He also discussed important aspects of physiology, medicine, the planet earth (including the oceans and the atmosphere), while contributing key insights to matter theory and the philosophy of science. Indeed, it is not too much to say that Boyle was one of the founders of the modern scientific laboratory—conceive an experiment to test a hypothesis, assemble the apparatus and the people needed to carry out the experiment, and publish the results.

Boyle’s books and articles were in high demand throughout Europe during the Scientific Revolution. They were often pirated on the Continent, where his name was recognized everywhere that science was being done. One reason for his international reputation, I am convinced, was the exquisitely detailed, very clear descriptions of his experiments. Others could repeat them to check the results, or modify them to test further hypotheses of their own. Either way, they could count on Boyle to report honestly exactly what he had done and found—even when the experiment didn’t work, a frequent occurrence. Because of his many important contributions to science, Boyle is often described as “the father of chemistry and brother of the Earl of Cork,” to borrow an old witticism that is—quite wrongly—said to be the epitaph on his tombstone. What is absent from this popular image, however, is a deeper understanding of a deeply religious man who wrote as much about the nature of God as he did about the nature of air.

Evidence of Boyle’s intense religiosity and its influence on his scientific work is abundant. A particularly striking example involves Richard Baxter, the eminent Puritan divine. After reading one of Boyle’s meditative works in the summer of 1665, Baxter wrote Boyle to express appreciation: “I read your Theologie as the Life of your Philosophie, & your Philosophie as animated & dignifyed by your Theologie; yea indeed as its first Part.” Once we realize that when Baxter used the word “Philosophie,” he meant what we call “science,” we start to see the point. As historian Michael Hunter has recently said, “The central fact of Boyle’s life from his adolescence onwards was his deep piety, and it is impossible to understand him without doing justice to this.” [Oxford Dictionary of National Biography(2004), vol. 7, p. 106.] The columns in this series should be understood as my effort to do it justice.

Bombarded by deafening claps of thunder in the dead of night, an adolescent boy awoke suddenly from a deep sleep, terrified by the loud darkness, punctuated by staccato flashes of light so frequent and dazzling that he imagined himself amidst the fire that would someday consume the world on the day of judgment.  Trembling at the hideous thought of being unprepared to face the awesome finality of that dreadful day, he solemnly resolved to live more piously henceforth. Not long afterward, in calmer circumstances, Robert Boyle repeated the vow made in fear with another, made “so solemnly that from that Day he dated his Conversion,” according to an autobiographical memoir written in his early twenties.

Boyle’s conversion took place at Geneva, in the home of his tutor, Isaac Marcombes, a Huguenot who had left France for Geneva owing to religious persecution. Marcombes’ wife was a niece of a famous Genevan preacher and Calvinist theologian, Giovanni Diodati, who translated the Bible into Italian and French. Marcombes took the adolescent Boyle to church twice weekly and read to him daily from the Bible and Calvin’s Catechism. Altogether young “Robyn,” as his family called him, spent five years on the Continent with Marcombes, studying rhetoric, logic, mathematics, and the art of fortification. Becoming fluent in French, he travelled extensively in France, Switzerland and Italy—he was in Florence when Galileo died.

Within months of his conversion, however, his new-found faith came under attack. His autobiography records how he became deeply depressed while visiting the original Carthusian abbey of Grande Chartreuse, located in what Boyle described as “those Wild Mountaines” near Grenoble. Although I’ve never been to the place myself, the pictures are simply spectacular, far more likely to produce rapture than dismay. Do you agree? If so, then what was Boyle’s problem

The problem is actually ours—or perhaps mine alone, since I’ve led you down this path. As L. P. Hartley so aptly said, “The past is a foreign country: they do things differently there.” Here’s what we’ve forgotten: many Europeans in Boyle’s day were distressed by mountains, which they regarded as ugly, postlapsarian blobs marring the surface of on an otherwise perfectly spherical Earth. Marjorie Hope Nicolson pointed this out many years ago. I like Jack Macintosh’s suggestion that this may have contributed to the dark mood that overcame Boyle on this occasion.

Whether or not Macintosh is correct, Boyle had a particularly bad experience there, which he saw in the following terms: “the Devil taking advantage of that deepe, raving Melancholy, [and] so sad a Place, his humour, and the st[r]ange storys & Pictures he found there of [Saint] Bruno the Father Patriark of that order; suggested such strange & hideous thoughts, & such distracting Doubts of some of the Fundamentals of Christianity,” that Boyle even contemplated suicide. Only “the Forbiddenesse of Selfe-dispatch” prevented him from taking that fatal step. “But after a tedious languishment of many months in this tedious perplexity,” he reflected, “at last it pleas’d God one Day [when] he had receiv’d the Sacrament, to restore unto him the withdrawne sence of his Favor.”

We do not know precisely which “Fundamentals of Christianity” Boyle questioned at that moment. We do know that, henceforth, wrestling with doubt was part and parcel of his profoundly religious life, such that “never after did these fleeting Clouds, cease now & then to darken the clearest serenity of his quiet.” As he wrote just a few years later, “Of my own Private, & generally unheeded doubts, I could exhibit no short Catalogue” (Essay of the Holy Scriptures, in The Works of Robert Boyle, vol. 13, p. 180). Ironically, doubt drove Boyle diligently to ferret out the rational foundations and implications of his faith, such that he “deriv’d from this Anxiety the Advantage of Groundednesse in his Religion: for the Perplexity his doubts created oblig’d him to remove them to be seriously inquisitive of the Truth of the very fundamentals of Christianyty.” Although “we cannot often give a Reason for What we beleeve; we shud be ever able to give a Reason Why we beleeve it.” It’s not hard to see why Boyle believed that “there is nothing worse taken up upon Trust then Religion.”

Religious doubt remained a defining characteristic of Boyle’s personality. Many of his mature works, dealing with various aspects of faith and reason, can be seen as parts of a lifelong conversation with his own soul. The constructive role that doubt played in Boyle’s life has often been overlooked. For example, the late Richard S. Westfall, one of the most influential scholars of the Scientific Revolution (and my own doctoral mentor), observed more than fifty years ago that the extensive attention Boyle and some of his contemporaries gave to “answering hypothetical atheists” in their writings was really more of an effort “to satisfy their own doubts” about the religious implications of the new science (Science and Religion in Seventeenth-Century England, p. 145). Although Boyle often engaged unidentified “atheists” in his writings—a topic I will come back to in a future column—there was more going on than Westfall apparently realized. Doubt is the other side of the coin of faith, and Boyle’s approach to it was frankly precocious. Not long after his twentieth birthday, in a notebook entitled “Diurnall Observations, Thoughts, & Collections,” Boyle recorded the following aphorism: “He whose Faith never Doubted, may justly doubt of his Faith.” Immediately before this, he had written, “The Dialect of Faith runs much upon the First Person[;] or True Faith speakes always in the First Persen.” Boyle understood both intuitively and cognitively a crucial fact about religious faith: it is a highly personal matter, and only those who take steps to examine their own beliefs can really lay claim to them and live accordingly. Needless to say, the conceptual box in which Richard Dawkins places religious faith will never hold Boyle’s.

Boyle’s faith was indeed his own, a product of thoughtful reflection as well as religious experience. “I am not a Christian, because it is the Religion of my Countrey, and my Friends,” he confessed at one point. “I admit no mans Opinions in the whole lump, and have not scrupled, on occasion, to own dissents from the generality of learned men, whether Philosophers or Divines: And when I choose to travel in the beaten Road, ’tis not because I find ’tis the Road, but because I judge ’tis the Way” (Reason and Religion, in The Works of Robert Boyle, vol. 8, p. 241). Precisely what Boyle meant by this, is best seen in a highly interesting unpublished treatise “On the Diversity of Religions” that survives among his papers.  “[N]ot only do far fewer religions differ fundamentally than men perceive,” he observed,

but far fewer men follow any of those religions of their own choice than some believe. For it is one thing for a man to profess this or that religion, but another thing entirely for him to choose the best. For the latter cannot be done save by one who has seriously and carefully examined the religion he has embraced in preference to others, and has compared it with them. But unless this serious and deliberate choice has taken place, one cannot legitimately conclude from the number of men adhering to that religion that it is the best. … Thus, when all things are duly considered, we may readily note that there are few who choose a given religion, even though there are many who follow it, for the rest all behave passively, so to speak, each man professing his religion more by chance than by judicious choice.

His overall conclusion was, “That a wise Christian should not be disturbed by the number and diversity of religions” (The Works of Robert Boyle, vol. 14, pp. 255-6 and 237).

Perhaps we might expect a 17^th-century English author to hold just such a view, informed more by ignorance than by objectivity. However, Boyle actually knew more than most of his contemporaries about religions other than Christianity, just as he was well read in the doctrinal controversies among Christians–especially those related to Socinianism, which he regarded as a dangerous heresy. He knew and respected the eminent rabbi Manasseh ben Israel, discussed the Hebrew language and Jewish beliefs with a Jewish scholar in London (whose name we don’t know), and even tried learning Arabic before weakening eyesight forced him to abandon the project. Actively seeking conversation with Jewish scholars, he regarded such “Fundamentall Controversys” as “both more Necessary & more Worthy a Wise mans Study, then most of those, comparatively Trifling ones, that at present so miserably (not to say so Causelessly) distract Christendome” (Essay of the Holy Scriptures, p. 217). Overall, Boyle’s encounter with doubt was undoubtedly positive.

Having taken full ownership of his faith, partly by giving doubt a free reign, Robert Boyle cultivated an active piety that friends noticed and admired–above all in his strict habit of honoring God’s name. Before turning twenty-one, he wrote two essays on the spiritual damage done by swearing that were published only after his death. Nor was he the least bit hypocritical in writing them. His close confidant, Bishop Gilbert Burnet, told mourners at Boyle’s funeral that their deceased friend “had the profoundest Veneration for the great God of Heaven and Earth, that I have ever observed in any Person. The very name of God was never mentioned by him without a Pause and a visible stop in his Discourse, in which one that knew him most particularly above twenty Years, has told me that he was so exact, that he does not remember to have observed him once to fail in it” (Robert Boyle: By Himself and His Friends, p. 48). When a prominent attorney, Sir Peter Pett, asked Boyle about this practice, this was Boyle’s answer: “not to have an awe upon us when the name of God is spoken of in Company, is a sign of want of Grace.” Boyle approached the Bible with a similar reverence, such that he gently reproved anyone who would use the words of Scripture in jest. As Pett recalled, “he inculcated the sinfulness of mens diminishing thereby the constant awe that the Scriptures should have on their thoughts: and minded the company of the Words of Isaiah to him will I look, who is of contrite heart & trembles at my word” (Robert Boyle: By Himself and His Friends, pp. 66-7).

Morning devotions were a standard part of Boyle’s daily routine, despite the fact that his eyesight was poor for most of his adult life. Judging from the number of times he cited them, two of his favorite biblical passages were Psalms 119 and 139, and a favorite verse was 1 Peter 1:12: “Unto whom it was revealed, that not unto themselves, but unto us they did minister the things, which are now reported unto you by them that have preached the gospel unto you with the Holy Ghost sent down from heaven; which things the angels desire to look into” (Quoting the Authorized Version, used in Boyle’s Anglican church). In keeping with this text, he hoped for a “dayly increase” in the number of those “who have such a desire as St.Peter tells us the Angels themselves cherish, to look into the Mysteries of Religion, and are qualified with elevated and comprehensive Intellects to apprehend them in some measure” (Style of the Scriptures, in The Works of Robert Boyle, vol. 2, p. 401).

This is precisely what Boyle tried to do himself: to develop a very serious interest in biblical scholarship, a trend apparently dating back to his youthful trip to the Continent. In Florence, Boyle met a Jewish refugee from Spanish persecution, a man with whom (according to Burnet) he “had many discourses about the Scriptures,” and “this led him first to enquire into them.” Several years later his father’s friend, the famous Archbishop James Ussher, reproached him for being ignorant of Greek, so “he studied it and read the N[ew] Test[ament] in that Language so much that he could have quoted it as readily in Greek as in English”—an observation affirmed independently by the Anglican rector in whose parish Boyle’s manor house was situated. As his eyes dimmed, he had to give up studying Hebrew, which none of his servants could read, but he was able to get help reading Greek. Despite his poor eyes, however, Pett reported that Boyle “alwaies had in his hand” in church a copy of the Bible in the original languages, which he liked to compare with the reading of the chapters assigned for that Sunday, “wondring to heare our English translation so different” from the original (Robert Boyle: By Himself and His Friends, pp. 27-8 and 65).

His love for God found further expression in love for his fellow human beings, starting with the tenants of his estate near the town of Stalbridge in North Dorset, close to the border with Somerset. The poorest residents annually received a cash gift at Christmas, distributed by his bailiff, who was also instructed not to oppress them with onerous rents. On other occasions, money would accompany medicines Boyle had made in his own laboratory for sick paupers. Many felt the gentle hand of his love, freely given and gratefully accepted. “His Charity to those that were in Want,” Burnet reminded Boyle’s friends at his funeral, was “so very extraordinary, and so many did partake of them, that I may spend little time on this Article. Great Summs went easily from him, without the Partialities of Sect, Country, or Relations; for he considered himself as part of the Humane Nature, and as a Debtor to the whole Race of Men.” Burnet had direct knowledge of this, having served often as an intermediary, helping to keep Boyle’s identity unknown to recipients. The donations for which Burnet could vouch (just a portion of Boyle’s philanthropy) sometimes exceeded £1000 per year, a very significant sum at the time—equivalent to roughly 3 million dollars today. Boyle also supported translations of part or all of the Bible into Welsh, Irish, Turkish, and Malayan, and Edward Pococke’s Arabic translation of Hugo Grotius’ important treatise, On the Truth of the Christian Religion.

One particular project stands out from the others, especially here in America: the first complete Bible printed in the Western Hemisphere, John Eliot’s translation into the Natick dialect (northern Algonquin) of the Indians in Massachusetts. Eliot’s labors to learn the language and to render it in the Roman alphabet were supported by a corporation established by the English parliament in 1649, during the Interregnum. After the Restoration in 1660, however, the corporation was effectively in legal limbo. Boyle was instrumental in obtaining a new charter from the crown, in response to a request from the Presbyterian divine Richard Baxter, who corresponded with Eliot and strongly supported his work. In 1662 Boyle was appointed the first Governor of the Company for the Propagation of the Gospel in New England, a position he held until1689 and carried out very conscientiously, with much energy. Although he made at least one large gift of £300 to the Company in 1679 and smaller ones directly to Eliot, his main contributions were political: he used his connections to ensure the viability of the Company, which still exists today. When Eliot prepared a new, revised edition, of his Bible (which appeared in 1685) following the destruction of many copies of the first edition in King Philip’s War, copies sent to England included a separately printed dedication to Boyle.

Christian love is no less evident in Boyle’s attitude toward individual persons in ordinary discourse. As Burnet said, “When he differed from any, he expressed himself in so humble and so obliging a way, that he never treated Things or Persons with neglect, and I never heard that he offended any one Person in his whole Life by any part of his Deportment” (Robert Boyle: By Himself and His Friends, pp. 50-51).  Boyle’s approach to intellectual opponents was identical, going out of his way on several occasions to treat their positions fairly and their persons graciously, while avoiding gratuitous ad hominem comments. Early in his scientific career, in a pioneering book devoted partly to the philosophy of science, he blazed a noble path in unambiguous prose: “I love to speak of Persons with Civility, though of Things with Freedom.” Concerning “the (very much too common) Practice of … railing at a mans Person,” as if it were “necessary to the Confutation of his Opinions, … I think such a quarrelsome and injurious way of writing does very much mis-become both a Philosopher and a Christian” (Certain Physiological Essays, in The Works of Robert Boyle, vol. 2, p. 26). Read his words again a couple times, and the significance of his faith for the practice of science may start to sink in.

Elsewhere (see my print essay, “Parcere nominibus,” cited below) I have shown the extent to which Boyle consistently kept this policy. Overall, Boyle left a remarkable legacy on this score. The contrast with someone like Galileo—who didn’t hesitate to get personal with opponents—is deafening. Although he was constantly in the public eye, often writing on controversial subjects and speaking with a wide range of people, he seems to have had many intellectual opponents but no real enemies–except philosopher Thomas Hobbes, a sometimes truculent man, “whose hand was against every body, & admir’d nothing but his owne,” to borrow the words of Boyle’s friend John Evelyn (Robert Boyle: By Himself and His Friends, p. 89). In the early 1660s, Hobbes and Boyle clashed over how to understand some of Boyle’s experiments with air pumps. Above all, they argued about how to interpret (in both physical and metaphysical terms) the space above the meniscus in a mercury barometer: is it really empty? How do we know that experiments with air-pumps give reliable information about nature?

The dispute with Hobbes took place on multiple levels. Boyle saw Hobbes’ concept of a corporeal God as “dangerous” to religion, and he was undoubtedly eager to respond pointedly for that reason alone. At the same time, he was exasperated by Hobbes’ persistent attack on scientific knowledge itself and offended by Hobbes’ condescending tone toward Boyle and his colleagues at the Royal Society. Nevertheless, even here Boyle sought to mollify rather than to escalate. His reply, taking the form of a supplement to the second edition of his great treatise on air pressure, was calculated “to give an Example of Disputing in Print against a Provoking, though unprovoked, Adversary, without Bitterness and Incivility, and without pursuing those things which [belong more] … to the Person of an Antagonist then to his Cause.” Inviting Hobbes to respond, Boyle advised “that his Reply be as inoffensive as I have endeavour’d to make [mine],” lest others be inclined to return his incivility (Examen of Hobbes, in The Works of Robert Boyle, vol. 3, pp. 111 and 114). Boyle’s moderation is a lesson for us all.

“[Because] the Publick Good is the advantage you propose to your self in all your Learned and Excellent Writings, .. you are deservedly styl’d every where, and particularly abroad, Philosophus Britannicus, theEnglish Philosopher.” –David Abercromby, A Moral Discourse of the Power of Interest (London, 1690), dedicatory epistle.

In the previous section, I provided some evidence of Boyle’s piety and devotion to God. We also saw how the latter motivated him to treat others charitably, even in scientific disputes. I now present further, equally important examples of Boyle’s Christian charity, in matters of conscience and in the importance of having a vocation of service to others.

Putting Piety into Practice: Christian Charity in Word and Deed

The Protestant Reformation of the 16th century resulted in the fragmentation of Christendom, giving princes religious excuses to make war for political gain and prelates excuses to persecute other Christians whose theological views they didn’t like to consolidate their power. Religious strife continued well into the next century. Matters were usually worse in several places on the Continent, but even in England Christians burned one another to death for believing the wrong things about Christ and his church. In the following century, the English Civil War had a significant religious dimension. It began while Robert Boyle was in Geneva—where he was being tutored by a Protestant refugee from religious persecution in France—but it was still going on when he returned from the Continent in the summer of 1644. Although he managed to stay out of the conflict personally, members of his large family were not unanimous in their loyalties. His own first thought was actually to join the King’s army—his brother Richard was a royalist officer—but his sister Katherine, who was closely tied to the Parliamentary faction, persuaded him not to do so. Boyle later saw this as a providential turn of events, by which he was not “expos’d to the manifold & great temptations of a Court & an Army, where … the generality of those he would have been oblig’d to converse with were very debaucht & apt, as well as inclinable to make others so” (Robert Boyle: By Himself and His Friends, p. 25).

It was indeed a very difficult time, especially for a pious and tender soul like Boyle, who was then just seventeen years old. Already as a young man, however, his tolerant attitude was forming. While Parliament was considering an ordinance making heresy a capital crime, Boyle wrote his former tutor to express strong dissent, saying, “why a man should be hanged, because it has not yet pleased God to give him his spirit, I confess, I am yet to understand. Certainly to think by a halter to let new light into the understanding, or by the tortures of the body to heal the errors of the mind, seems to me like applying a plaister to the heel, to cure a wound in the head; which doth not work upon the seat of the disease” (The Correspondence of Robert Boyle, vol. 1, p. 40).

Boyle’s vision of a world free of religious persecution did not go unnoticed in his day. Although he always supported the established Anglican church, one of his pastors (Stalbridge rector Thomas Dent) observed that he “was for moderation to those, who dissented from us, & not to force Tender consciences–for which he seem’d to expresse great aversen[ess].” According to Gilbert Burnet, a liberal churchman who knew his views as well as anyone, Boyle “had a most peculiar zeal against all Severities and Persecutions upon the account of Religion. I have seldom observ’d him to speak with more Heat and Indignation, than when that came in his way.”  Indeed, Boyle considered religious persecution “Immorall.” Burnet’s description of Boyle’s overall religious attitude is revealing. “He always considered [Christianity] a System of Truths, which ought to purifie the Hearts, and govern the Lives of those who profess it; he loved no Practice that seemed to lessen that, nor any Nicety [i.e., point of doctrine] that occasioned Divisions amongst Christians. He thought pure and disinteressed Christianity was so Bright and Glorious a thing, that he was much troubled at the Disputes and Divisions which had arisen about some lesser Matters, while the Great and the most Important, as well as the most universally acknowledged Truths were by all sides almost as generally neglected as they were confessed” (Robert Boyle: By Himself and His Friends, 105, 49, 28, and 48).

The ecumenical attitude evident in much of Boyle’s writings has long made me suspicious of several scholarly works that present Boyle as an anti-Catholic thinker and writer. To be sure, Boyle had thought about the issues separating Protestants and Catholics, just as he had thought about so many other important religious matters. When asked, he could articulate objections to Catholicism. For example, there is a long, fascinating letter to Boyle from an Italian Jesuit scholar, Lorenzo Magalotti, who had visited Boyle while accompanying the crown prince of Tuscany, the future Duke Cosimo III de’ Medici, on a trip to London in the spring of 1669. When Magalotti fell ill with a fever, Boyle spent two or three hours with him every day. About three years later, in the only letter between the two men that still survives, Magalotti responded to objections Boyle had apparently voiced against Catholicism during their time together and tried to draw Boyle into further conversation.

Magalotti’s comments about Boyle’s character only reinforce what I’ve already said. “You are not alone in knowing the true measure of your desire to love God. First of all, your servants know it—your servants towards whom the zeal of your charity is so tender that after your feeding of them no less with material bread than with the milk of philosophy, they change the simplicity of their livery for doctoral clothes, by employing (especially for the benefit of the poor) that treasury which they have gathered up from the phials of your most noble foundry. I saw them running through London in the public squares with extraordinary piety helping poor epileptics with the comfort of very powerful remedies which they were accustomed continually to take with them for this very purpose alone” (beautifully translated by Lawrence Principe, in The Correspondence of Robert Boyle, vol. 4, p. 266).

After ingratiating himself to his English friend here and in other ways, however, Magalotti gently chastised Boyle for not trying to convert him! “I said to myself, if Mr Robert, as a claimant to the title of a follower of the Gospel, truly loves me as himself, and then loves me yet again as a friend, how can it happen that he has never tried, throughout all this time, with either spoken or written words, to make sure that I could have the benefit of that good he hopes for by the merit of his religion?’” Answering his own rhetorical question, Magalotti wrote, “either he does not believe that he needs to try to come to where you are, or at least does not believe that you need to move from where you are” (The Correspondence of Robert Boyle, vol. 4, pp. 271-2).

As far as we know, Boyle never replied to this letter, and I cannot answer Magalotti’s question confidently on his behalf. But, we can say at least this much, based on the whole conduct of his life and the whole content of his writings: Boyle knew why he wasn’t a Catholic, and he regarded some Catholic beliefs as no more than vulgar superstitions. He was willing to discuss this privately, but not publicly in print. He probably viewed Catholics (in general) as fellow Christians who did not need to convert in order to attain salvation, even though he certainly felt that Protestants had a better grounding for their faith. Above all, he had no taste for putting anti-Catholic arguments into his books: he never sought to advance controversies among Christians.

For reasons such as these, I never believed that Boyle wrote an anonymously published tract called Reasons Why a Protestant should not Turn Papist—despite the fact that for a long time most scholars believed that he did, including John Farquhar Fulton, the physician and historian of medicine who compiled the standard bibliography of Boyle’s works. Many years ago, I found decisive evidence confirming my conviction. In a surprising turn of events, the real author turned out to be the Scottish physician David Abercromby, a former Jesuit who had become a Protestant and who worked for Boyle in the 1680s.

The source of Boyle’s generous ecumenism is often said vaguely to be his sympathy with the broadly tolerant “Latitudinarian” wing of the Anglican Church, which sought to avoid both a rigid Calvinism on the one hand and an equally rigid Catholicism on the other hand. It is more helpful to point to some specific influences early in Boyle’s life. Peter Anstey stresses the significance of two different, but somewhat overlapping, sources. One was the Dutch statesman and jurist Hugo Grotius, whose work, On the Truth of the Christian Religion (1627), Boyle obviously admired, since he paid Edward Pococke to translate it into Arabic. With his countryman Jakob Hermanszoon (better known by his Latin name “Arminius”), Grotius admired the tolerant Christian humanism of Erasmus. He hoped that reason might be able to sort out religious differences among Christians, while at the same time showing the overall truth of Christianity. In England, Grotius’ attitude was adopted and his ideas were adapted by several members of the “Great Tew” circle, a group who gathered for intellectual exchanges at the home of Lucius Cary near Oxford. Boyle knew Cary and some of the others, and the charitable approach of Erasmus’ disciples seems to have shaped his thoughts, words, and deeds. On the other hand, Grotius’ thought was repeatedly attacked by the Puritan theologian John Owen, who viewed him as a Socinian heretic. Facts such as these make it very difficult to claim Boyle for the Puritan camp, as some have done. If his piety closely matched the Puritan ideal, his ecumenism and eclecticism did not.

A complementary influence, as John Harwood has shown, was the massive Encyclopædia (1630) compiled by German theologian Johann Alsted, under whom the great Czech educational reformer John Comenius studied. Boyle consulted it heavily in his twentieth year, while he was busy at work on a lengthy essay about happiness and moral virtue that he never published. It was through writing this and some other early essays, Harwood argues, that Boyle “found a vocation, a concept crucial to the moral life.” He did this self-consciously, and he understood its significance at the time, stressing that “it is very requisite (if not absolutely necessary) to settle our Youth … in a fit Vocation, … because A Convenient civil Calling is a sovveraigne Preservative agenst Idleness, (that mother of Vices) and an excellent prevention of a world of Idle, Melancholick and exorbitant thouhts, and un-warrantable Actions” (The Early Essays and Ethics of Robert Boyle, pp. xliv and 85).

What follows shortly after this is one of the most revealing statements Boyle ever entrusted to paper: “He is but an useless wastful Droane, and unworthy of the Benefits of Humane Society; whose endeavors in som honest particular Calling, do not som way or other Cooperate (and contribute) to the Good of the Common-welth.” He went on to say, “While a Gentleman” is “busying himself in any lawfull Employment that tends to the Good, of himself, his Family, others, or the Commonwelth, he may be (favorably) beleeved to be diligent to embrace in his Profession. But when a Gentleman … shal spend his whole stock of precius time in Carding, Dicing, Hunting, revelling, Seeing of Plays, Reading of Romances, Powdring his haire, Staring upon looking-glasses, courting of Ladys that he means not to marry (not to mention what is worse) and in Sum make Vacation his only Vocation: he must have a Stronger Charity than Judgment, that beleeves that God and Nature intended only this for that man’s Calling.” Though Boyle dearly hoped that “pray God we have not too many” like the latter, his circumstances must have provided abundant opportunities for second thoughts—as we shall see in the next section (The Early Essays and Ethics of Robert Boyle, pp. 85 and 88).

Why Boyle Became a Scientist

It was only after writing all of the religious works I’ve already told you about, at some point in his twenty-third year, that Boyle embarked on serious scientific study. From that point on his pursuit of natural philosophy continued unabated until his death. Often we do not know precisely why a given person is drawn to any specific activity, and we must be careful not to jump to inappropriate conclusions simply by assuming a certain answer. As Mordechai Feingold has stressed, we must keep in mind the distinction between one’s actual motivation for doing science and the justification one then offers for it. This caveat is especially relevant to the Scientific Revolution, when so many scientists were ordained ministers who felt tugged in opposite directions by their callings as clergy and their fascination with mathematics or natural philosophy. Although Boyle was never ordained, we must still be careful not uncritically to equate his reasons for doing science with the justification he provided.

They were however very closely linked in his case. Clearly, Boyle found himself enraptured by his first experiences in the laboratory, and just as clearly he viewed his activities simultaneously in theological terms. His own account, from an exuberant letter to his sister Katherine, is mythical in its allusion and proportion: “Vulcan has so transported and bewitch’d mee, that as the Delights I tast in it, make me fancy my Laboratory a kind of Elizium; so as if the Threshold of it possest the quality the Poets ascrib’d to that Lethe their Fictions made men taste of before their Entrance into those seats of Blisse.” In short, Boyle simply lovedgetting his hands dirty doing chemical experiments. No surprise there, given how much time he would devote to them.

Just three sentences earlier, however Boyle had already mentioned “those Morall speculations, with which my Chymicall Practices have entertained mee,” mentioning specifically in this connection “a Discourse … of the Theologicall Use of Naturall Filosophy; endeavoring to make the Contemplation of the Creatures contributory to the Instruction of the Prince, & to the Glory of the Author of them” (The Correspondence of Robert Boyle, vol. 1, pp. 82-3). The “Discourse” Boyle referred to was an essay, “Of the Study of the Booke of Nature,” which he originally intended to include with the homilies and meditations comprising Occasional Reflections. This is strong evidence by itself of the intimate connection that Boyle saw, right from the start, between his already highly developed religious life and his newly developing interest in science.

As this early essay reveals, even before beginning his laboratory activities Boyle was profoundly convicted that the investigation of nature was a fundamentally religious enterprise. “Both our Divines & our Philosophers,” the essay begins, “compose Man’s Library of three cheife Bookes, which to Expound, apply & Rectify, is the Taske of the rest.” What three “Bookes” did he have in mind? The “3 Volumes, are The Booke of Nature, the Book call’d Scripture, & the Booke of Conscience.” Having already said much about the latter two books in many other writings, Boyle’s goal in this essay was to “addict … all capable & Intelligent Persons to the neglected study of the First,” that is, nature (The Works of Robert Boyle, vol. 13, p. 147). The intimate interplay between scientific and religious ideas would henceforth be an outstanding feature of his thought.

A further motive was Boyle’s strong desire to improve the human condition and to ameliorate suffering—especially through the application of chemical knowledge to medicine. The modern advertising slogan, “Better Living Through Chemistry,” never had a better exemplar than Robert Boyle. To some extent, Boyle’s interest in medicine reflected some unfortunate encounters with unhelpful physicians and his own generally poor health. His friend John Evelyn described him as “rather talle & slender of stature,” but “pale & much Emaciated,” and his diet as “extreamely Temperate & plaine” (Robert Boyle: By Himself and His Friends, pp. 88-9). More importantly, Boyle deeply felt that physicians had a religious duty to be more forthcoming with effective remedies—and to provide them even to those who could not afford to pay. It was a lifelong theme, running through many of his writings, which came to a climax near the end of his life, when he published a collection of medical recipes for this very purpose. John Wesley did precisely the same thing, for the same reasons, in the following century.

Boyle the Laboratory Scientist

Once Boyle had begun the investigation of nature, he never slackened, and he found his Christian character ideally suited to his new activities. The highly competitive aspect of modern science sometimes hides the fact that science is a fundamentally cooperative enterprise, in which groups of people work toward common goals. Boyle’s unquestioned honesty, unfailing charity, and genuine interest in the public welfare helped him gain the respect and friendship of an important community of learned “gentlemen,” who met regularly in John Wilkins’ rooms at Wadham College, Oxford, to view experiments and to discuss the latest scientific discoveries and ideas. When Wilkins moved to Cambridge in 1659, Boyle assumed the role of host. The following year, he and some of the same people joined with several others in London to found the Royal Society.

The next dozen years were the most productive of his life, earning him a worldwide reputation as the outstanding experimental scientist of his generation. His most famous contributions involved the use of an air pump, expertly made for him by Robert Hooke, a brilliant Oxford student who went on to become a great scientist himself. With this apparatus, Boyle demonstrated several properties of the air, confirming in clear and clever ways the hypothesis of Blaise Pascal and others that the atmosphere is a vast fluid like the ocean. Just as water pressure increases with depth, so air pressure depends on the height of the atmosphere. Several other experiments, involving insects, birds, and small mammals, helped to illuminate the connections among respiration, combustion, and various components of the air.

Boyle’s involvement with animal experimentation calls for more comment. The Greco-Roman anatomist Galen had carried out numerous experiments on living animals–it was the only way in which many physiological phenomena could be seen at that time. However, according to Anita Guerrini, his methods were not employed again as part of a scientific research program until the first quarter of the 17th century, when the Oxford physician William Harvey used vivisection to help establish the circulation of the blood. By the 1650s, animal experimentation was practiced widely in England and had become indispensable for understanding respiration, in which Boyle and several of his contemporaries had keen interest.

For this and other purposes, Boyle carried out numerous experiments involving live dogs, cats, birds, mice, frogs, snakes, worms, and insects. He repeated what he called “the Experiment of killing Birds in a small Receiver” often enough to refer to it in that matter-of-fact manner. To some extent, animal experimentation was encouraged by René Descartes’ view that animals were merely machines lacking reason and sensation, a concept that became known as the “beast-machine,” but Boyle did not entirely accept that notion. He sometimes expressed remorse for laboratory animals, on the assumption that they actually did suffer, and even showed compassion in some cases by declining to subject animals to multiple experiments. As Malcolm Oster has shown (cited below), Boyle considered gratuitous cruelty to animals blasphemous, while at the same time he believed it legitimate to use animals for experiments that would advance human knowledge.

Boyle and the Mechanical Philosophy

During the Scientific Revolution, no idea was more influential—or more important for the future of science—than the “mechanical philosophy.” Mechanical philosophers conceived of nature as a great machine, an intelligently constructed system of unintelligent matter in motion rather than a living organism with a “soul” or “intelligence” of its own. No one did more to advocate for the mechanical philosophy—and to explore its theological dimensions—than Robert Boyle. The magnitude of his enthusiasm for it is best captured by this fact: when he published a treatise on The Excellency of Theology, Compar’d with Natural Philosophy (1674), it was coupled with a second work devoted to “the Excellency and Grounds Of the Corpuscular Or Mechanical Philosophy.”

The mechanical philosophy was essentially a modified version of ideas originally put forth by the ancient philosophers Leucippus, Democritus, and Epicurus. As they had presented it, atomism came with strong overtones of atheism: all things are composed of eternal, uncreated, invisibly small, indivisible particles, called “atoms” because they cannot be “cut’ into smaller pieces. The atoms move randomly and without purpose in an infinite void, bumping into one another to form macroscopic objects, including living things.

During the Scientific Revolution, however, atoms mostly lost their irreligious image, as Pierre Gassendi and others “baptized” atomism. Their general approach was to postulate atoms as divinely created particles of inert matter, with properties and powers given to them by God, who guided their motions to form larger bodies. In 1659, Boyle’s friend Henry More called this idea the “Mechanick philosophy,” and two years later Boyle himself called it “the Mechanical Hypothesis or Philosophy,” marking the first use of that exact term that I am aware of (Certain Physiological Essays, in The Works of Robert Boyle, vol. 2, p. 87).

The Christianization of atomism was a crucial step, for it enabled the adoption of a new worldview—a complete change in the way in which nature was conceived. For nearly two thousand years, the prevailing concept of nature came not from the atomists, but from Aristotle and Galen. This notion depicted “Nature” as a wise, benevolent being, capable of acting almost like a conscious agent, as seen in phrases such as “Nature does nothing in vain,” “Nature abhors a vacuum,” or “Nature is the wisest physician.” By contrast, for Boyle and other mechanical philosophers, the world was a vast, impersonal machine, incapable of acting consciously. Perhaps surprisingly, Christian theological beliefs helped drive this enormous conceptual shift that lies at the heart of modern science, in ways that historians have not fully appreciated until fairly recently.

Boyle was a crucial player in this important process. He believed that the traditional notion of “Nature” was both theologically and scientifically unacceptable. I will say more about the theological part in future columns. For now, let’s focus on the scientific part.

As Boyle saw it, Aristotle’s system suffered from a fundamental conceptual problem that had to be eliminated before scientific progress could be made. It implicitly gave matter the ability to think: how else (to offer an example of my own) could a body return to its “natural place,” unless it knew that it had arrived there? Properly speaking, Boyle argued, matter is utterly incapable of obeying “laws” (a term Boyle nevertheless employed often), because it lacks innate intelligence and cannot know whether or not it has obeyed. Likewise, when we use “such Phrases, as, that Nature …, or Suction, doth this or that,” we “ascribe to a notional thing, that which, indeed, is perform’d by real Agents; as, when we say, that the Law punishes Murder with Death, that it protects the Innocent, releases a Debtor out of Prison, when he has satisfied his Creditors (and the Ministers of Justice) on which, or the like occasions, we may justly say, That ’tis plain that the Law, which, being in it self a dead Letter, is but a notional Rule, [and] cannot, in a Physical sense, be said to perform these things.” What really does perform things in nature, according to Boyle, is “those Powers, which [God] gave the Parts of Matter, to transmit their Motion thus and thus to one another” (A Free Enquiry into the Vulgarly Reciev’d Notion of Nature, in The Works of Robert Boyle, vol. 10, pp. 464 and 457). Here we have the mechanical philosophy in a nutshell.

Aristotelian philosophy also explained many aspects of nature in terms of immaterial “forms and qualities” inherent to bodies. Boyle and other mechanical philosophers found such analyses vague and incapable of providing convincing explanations. As the prominent Anglican cleric Simon Patrick frankly observed, “To them that have once tasted of the Mechanicall Philosophy, formes and qualities are like to give … little satisfaction” (A brief account of the new sect of latitude-men: together with some reflections upon the new philosophy, 1662, p. 22).

To see why Boyle regarded mechanical explanations as superior, consider the maxim that “Nature abhors a vacuum.” Boyle flatly rejected that idea. “When I consider, how great a Power the School Philosophers [i.e., followers of Aristotle] ascribe to Nature, I am the less inclin’d to think, that Her abhorrence of a Vacuum is so great, as they believ’d” (A Free Enquiry into the Vulgarly Reciev’d Notion of Nature, in The Works of Robert Boyle, vol. 10, p. 536). Drawing on dozens of experiments he had carried out with an air pump, Boyle concluded that for practical purposes one could indeed create a vacuum, even though (in his opinion) the formal philosophical question of the actual existence of a space completely empty of all matter could not be settled with certainty. The ultimate inspiration for many of his experiments came from an experiment carried out in 1644 by Vincenzio Viviani, a former assistant of Galileo who was a student of Evangelista Torricelli. (See the caption to the image for more information.)

As Boyle observed, “when the Torricellian Experiment is made, though it cannot, perhaps, be cogently prov’d, … that, in the upper Part of the Tube, deserted by the Quick-Silver [mercury], there is a Vacuum in the strict Philosophical Sense of the Word; yet, … ’twill to a heedful Peruser appear very hard for [followers of Aristotle] to shew, that there is not One in that Tube.” Considering “the Space deserted by the Quick-silver at the top of the Pipe, … One may be Invited to doubt, Whether a Vacuum ought to be thought so formidable a Thing to Nature, as they imagine She does, and ought to, think It?” (A Free Enquiry, in The Works of Robert Boyle, vol. 10, pp. 536-7)

Furthermore, the strength of the vacuum—corresponding to the height of the mercury in the tube—depended only on the pressure of the atmosphere, not the ability of an imaginary being called “Nature” to prevent it. To investigate “the old Doctrine of the Schools, which would have Water raiseable in Pumps to any height, ob fugam vacui [to avoid a vacuum],” Boyle mounted a long metal pipe on the side of a house “about 30 foot high,” with a reservoir of water on the ground and a transparent glass tube at the top in order to observe the level reached by the water as the pump was operated. (See the figure.) When “the height of the Cylinder of Water was measur’d,” it came to 33½ feet, but no higher— regardless of how hard the pump was worked. At that point, “I return’d to my lodging, which was not far off, to look upon the Baroscope [barometer], to be informed of the present weight of the Atmosphere, which I found to be but moderate, the Quick-silver standing at 29 inches, and between 2 and 3 eights of an inch.” Boyle knew that mercury is about 13½ times the density of water. Thus, he concluded that “the difference between the height of the Mercury sustain’d by the weight of the Atmosphere in the Baroscope, and that of the Water rais’d and sustain’d by the Pressure of the same Atmosphere in the long Tube did not appear to differ more than an Inch or two from the proportion they ought to have had, according to the difference of their specifick Gravities” (A Continuation of New Experiments, in The Works of Robert Boyle, vol. 6, pp. 70-73).

Boyle interpreted such experiments in terms of the mechanical philosophy. Instead of saying vaguely that “Nature abhors a vacuum,” which implied that water and mercury could be raised to any height by a pump, he said more precisely that “the weight of the Atmosphere” balanced the weight of the water in the metal pipe and the weight of the mercury in the glass tube. This explained precisely why water and mercury rose to specific, quite different heights.

Altogether, we might say that Boyle abhorred the Aristotelian notion of “Nature” much more than “Nature” abhors a vacuum.

Why Boyle Found the Mechanical Philosophy So Attractive Theologically

Boyle’s belief in the biblical God substantially motivated his wholehearted embrace of the mechanical philosophy. He thought it was actually more consistent with biblical statements of divine sovereignty than the non-mechanistic views of Aristotle and Galen. This is the argument of his subtle treatise about God and nature, A Free Enquiry into the Vulgarly Receiv’d Notion of Nature, much of which was written at the height of his powers (in the 1660s) though it wasn’t published until twenty years later. To understand what he meant by the “Vulgarly Received Notion of Nature,” remember that “vulgar” originally meant ordinary or commonplace, and that Jerome’s Latin translation of the Bible was called the “Vulgate” for that reason. Boyle was referring to the Greek conception of nature, which was still widely accepted.

What did he think of the Greek notion of nature? Simply put, Boyle believed it was inappropriate—both theologically and scientifically—to speak of “Nature” doing anything at all. We’ve already had a glimpse of his scientific objections in my previous column. What were his theological objections? For starters, he couldn’t find an equivalent notion in the Bible. “I do not remember, that in the Old Testament, I have met with any one Hebrew word that properly signifies Nature, in the sense we take it in.” Though biblical authors “many times mention the Corporeal Works of God, yet they do not take notice of Nature, which our Philosophers would have his great Vicegerent in what relates to them.” Indeed, when Paul wrote to the Corinthians, “who were Greeks,” about sowing seeds (1 Cor. 15: 37-8), “he does not attribute the produc’d Body [the mature plant] to Nature, but when he had spoken of a grain of Wheat, or some other seed put into the ground, he adds, that God gives it such a Body as he pleaseth, and to every seed its own Body, i.e. the Body belonging to its kind” (The Works of Robert Boyle, vol. 10, pp. 459-60).

In other words, a more biblical conception of nature will focus on the properties and powers freely given to bodies by the Creator himself, not on an imaginary “Vicegerent” called “Nature,” that stands like “a Goddess, or a kind ofSemi-Deity” between God and his creation (p. 456). By removing “Nature” as an intermediary, the mechanical philosophy benefitted theology by underscoring divine sovereignty: nature is a creation, not an independent being, and its created properties and powers are the proper subject of our study. At the same time, the “vulgar” view holds back scientific progress; “the veneration, wherewith Men are imbued for what they call Nature, has been a discouraging impediment to the Empire of Man over the inferior Creatures of God.” Many even thought it was actually “impious” to transcend “those Boundaries which Nature seems to have put and setled among her Productions.” Those who view “Nature” as “such a venerable thing … make a kind of scruple of Conscience, to endeavour so to emulate any of her Works, as to excel them” (p. 450). What Boyle called “the Empire of Man” was nothing other than the Genesis mandate, God’s command to humanity to “rule over” the rest of creation. To the extent that Greek conceptions impeded human dominion, to the same extent they were theologically objectionable.

Boyle’s Clockwork Universe

Finally, by underscoring the wonderful, astonishing complexity and intricacy of the created order, the mechanical philosophy powerfully focused our attention on the Creator: his wisdom, power, and goodness are seen abundantly in the creation. This is where the notion of a clockwork universe comes in: the mechanism requires a mechanic to make it. Boyle was hardly the first person to use the clock metaphor, but I doubt that anyone used it more often or more enthusiastically. Even before he adopted the mechanical philosophy, he had encountered essentially the same idea in A Woorke concerning the trewnesse of the Christian Religion, a treatise by the Huguenot writer Philippe de Mornay that deeply influenced Boyle’s development as a Christian thinker. Although Mornay was not (as far as I can tell) a mechanical philosopher, he spoke of “the great wheele of Heaven,” which “hath now of long time turned about without ceasing, wilt thou be so childish or so blind, as to belieeve that it hath turned so from everlasting? O man, the same workmayster which hath set up the Clock of thy hart for halfe a score yeares, hath also set up this huge engine of the Skyes for certeyne thousands of yeares” (p. 100).

Boyle appealed specifically to the clock metaphor in arguing for the superior theological implications (as he saw them) of the mechanical philosophy. Proponents of the vulgar conception of nature “seem to imagine the World to be after the nature of a Puppet, whose Contrivance indeed may be very Artificial, but yet is such, that almost every particular motion the Artificer is fain (by drawing sometimes one Wire or String, sometimes another) to guide, and oftentimes over-rule, the Actions of the Engine; whereas, according to us, ’tis like a rare Clock, such as may be that at Strasbourg, where all things are so skilfully contriv’d, that the Engine being once set a Moving, all things proceed according to the Artificers first design, and the Motions of the little Statues, that at such hours perform these or those things, do not require, like those of Puppets, the peculiar interposing of the Artificer, or any Intelligent Agent imployed by him, but perform their functions upon particular occasions, by vertue of the General and Primitive Contrivance of the whole Engine” (The Works of Robert Boyle, vol. 10, p. 448).

The Relevance of Robert Boyle Today

Boyle’s clockwork universe united his natural theology inextricably with the mechanical philosophy. The degree to which the subsequent Anglo-American tradition of natural theology derives its impulse and content from Boyle is not fully appreciated: even Paley’s watch on a heath was already lodged in Boyle’s pocket. Consider the following passage, probably written in the last decade of Boyle’s life but never actually used in any of his printed books. A transcription was eventually published by Jack MacIntosh in 2006, but I’ll quote a copy of the manuscript I obtained in 1989, when I first read it in the library of the Royal Society and was thunderstruck by the remarkable similarity to Paley’s famous analogy: “if an Indian or Chinois [Chinese], should have found a Watch cast on shore in some Trunke or Casket of some shipwrackt European vessel; by observing the motions and figure of it, he would quickly conclude that ’twas made by some intelligent & skillfull Being” (Royal Society, Boyle Papers, vol. 5, fol. 105). Insofar as the modern ID movement is deeply indebted to Paley (and it is), it is no less indebted to Boyle.

The rock-bottom issue for Boyle—how we should conceive of nature—remains equally relevant to certain other important conversations today. Some feminists and environmentalists want us to reverse course and stop thinking of nature as an impersonal thing; they seem to prefer “Mother Nature,” or something similar. Some theologians (a prominent example is David Ray Griffin) want us to abandon the notion of a transcendent God; they would prefer to revive the Stoic notion of the “world-soul,” which Boyle vigorously opposed. Readers interested in any of these debates stand to benefit greatly from studying this subtle book—which is now back in print after three centuries.

I close with that recommendation.

Coupled with his commitment to the mechanical philosophy, Boyle also endorsed “methodological naturalism,” the philosophical position that miracles aren’t appropriate scientific explanations. At the same time he aggressively promoted “intelligent design.” Both parts of that interesting combination—which might strike readers as paradoxical—will be examined in the next section.

Does God act in nature? If so, should scientific explanations occasionally include divine action as part of the causal nexus accessible to scientific inquiry? Surprisingly, Boyle’s experiments with air raised just such questions. Although Boyle himself didn’t initiate those conversations, his answers are important—and highly relevant to contemporary discussions of “naturalism” in science.

Boyle’s Barometer and God’s Absolute Power

Robert Boyle didn’t invent the barometer, but he was the first person to call it that. He also experimented extensively with it, even building a portable version of the instrument that worked tolerably well and—Boyle suggested hopefully—might perhaps be modified to be “serviceable at Sea,” though he “had no opportunity to try” one under those conditiions (A Continuation of New Experiments Physico-Mechanical, in Works of Robert Boyle, vol. 6, p. 93).

As I pointed out earlier, some of Boyle’s experiments led to fascinating debates about the space above the meniscus in a mercury barometer: is it really completely empty of matter? It wasn’t a purely physical question; a metaphysical dimension was also prominently present, as Steven Shapin and Simon Schaffer have shown. Even today, metaphysical issues are not entirely separate from science (despite the reluctance of some scientists to acknowledge it), but during the Scientific Revolution they were almost ubiquitous.

One of Boyle’s most vociferous opponents on this occasion was Francis Line, an English philosopher who spent much of his life in exile on the Continent, partly as professor of mathematics and Hebrew at the College of the English Jesuits at Liège. Line was born into a Catholic family, and England had strict laws against propagating Catholicism, dating back to before his birth. Thus, as his biographer says, “no doubt, Francis was baptized in secret” (Conor Reilly, Francis Line, p. 5). He went on to become a Jesuit priest, making him persona non grata throughout the English realm and placing him effectively under a death sentence, if he were discovered to be pursuing his calling in his homeland. Nevertheless, Line quietly returned to England at some point in the 1650s, not long before Boyle started exploring the properties of air.

When Boyle’s famous book about the air pump came out in 1660, Line read it right away. He had done some pneumatical experiments of his own at Liège, but he did not believe in the possibility of creating a vacuum so he interpreted them differently. The following year, he challenged Boyle’s views in a Latin treatise, Tractatus de corporum inseparabilitate (1661), or “A Treatise on the Inseparable Nature of Bodies,” arguing that a genuine vacuum is impossible. The apparently empty space above the meniscus in the barometer was the subject, and the need for nature to avoid a vacuum was the problem. What was the solution? Line proposed that something he called a “funiculus,” formed from the “rarefied and extended upper surface of the mercury,” functions like a string adhering to the top of the glass tube, upholding the column of mercury in the tube and preventing a vacuum from forming (translation from Reilly, Francis Line, p. 66). In this way, Line believed he could preserve the Aristotelian principle that “Nature abhors a vacuum.”

How could this be possible? How could the mercury itself expand almost magically in this way, as if on demand in order to prevent a vacuum? According to Line, such a thing was at least possible “divinitus”—in other words, by God’s absolute power—and therefore it had to be consistent with the nature of matter. The sound of Boyle taking a deep breath is audible even now. “None is more willing to acknowledge and venerate Divine Omnipotence” than me, he replied, entirely without exaggeration. “I say, that our Controversie is not what God can do, but about what can be done by Natural Agents, not elevated above the sphere of Nature. For though God can both create and annihilate, yet Nature can do neither: and in the judgment of true Philosophers I suppose our Hypothesis would need no other advantage to make it be preferred before our Adversaries, then that in ours things are explicated by the ordinary course of Nature, whereas in the other recourse must be had to miracles” (Defence Against Linus, in The Works of Robert Boyle, vol. 3, p. 48).

“Our Hypothesis would need no other advantage …” Those are very significant words, barring the door to the direct invocation of God’s absolute power as an explanation in natural philosophy. Boyle was fully persuaded that God had worked numerous miracles, and that even now God could set aside “his ordinary and general Concourse” (as Boyle liked to put it) for some special purpose. But natural philosophy could not be built on rare acts of God that we cannot control or replicate. Invoking God in that way was nothing more than a shell game, hiding our inability to know the real cause of a phenomenon.

For example, consider the cause of the dark skin of Africans. Boyle was not impressed by those who “would have the Blackness of Negroes an effect of Noah’s Curse ratify’d by God’s, upon Cham; But though I think that even a Naturalist may without disparagement believe all the Miracles attested by the Holy Scriptures, yet in this case to flye to a Supernatural Cause, will, I fear, look like Shifting off the Difficulty, instead of Resolving it; for we enquire not the First and Universal, but the Proper, Immediate, and Physical Cause” (Experiments and Considerations Touching Colours, in The Works of Robert Boyle, vol. 4, p. 88).

Boyle objected to traditional Aristotelian explanations for similar reasons: they were a cloak for ignorance. Aristotelian forms and qualities were said to explain how the physical properties of bodies were produced. Why does snow dazzle the eyes more than grass? Here is Boyle’s opinion of the traditional Aristotelian answer:

“to say, that these and the like Effects are perform’d by the substantial Forms of the respective Bodies, is at best but to tell me, what is the Agent, not how the Effect is wrought; and seems to be but such a kind of general way of answering, as leaves the curious Enquirer as much to seek for the causes and manner of particular Things, as Men commonly are for the particular causes of the several strang Things perform’d by Witchcraft, though they be told, that tis some Divel that does them all” (Origin of Forms and Qualities, in The Works of Robert Boyle, vol. 5, p. 352).

The devil, it seems, was not to be found in the details.

Methodological Naturalism

What Boyle was driving at is one of the most contentious ideas in the contemporary controversy over origins: methodological naturalism, the idea that scientific explanations ought to refer only to “natural” causes, such as “natural” laws, mechanisms, or forces. Basically, Boyle endorsed methodological naturalism. At the same time, he completely rejected ontological naturalism, the belief that nature is all there is, denying the existence of God and any other “supernatural” entities. All Christian thinkers reject ontological naturalism—at least they ought to, if they want to be taken seriously both as Christians and as thinkers—but many Christian scientists accept methodological naturalism. Proponents of Intelligent Design typically do not accept it. In their view, it collapses all too easily into ontological naturalism.

Questions about the nature of scientific knowledge, including the limits of naturalism and the implications of God’s absolute power for our ability to understand the “natural” world, are not capable of easy answers that will be obvious to all. Science itself doesn’t answer normative questions like these. They go beyond science into metaphysics—a way of thinking that contemporary scientists tend to disparage and ignore, such that they sometimes find themselves in the unenviable state of being ignorant of their own ignorance. That is why conversations like this are still relevant.

I’ll close by stepping back into history from philosophy. Historians don’t actually know very much about the history of naturalism and the (philosophical and theological) debates surrounding it. I once read a short paper at an academic conference about that very topic that might result in a book about it, but I don’t expect it to be the last word. Suffice it to say that scientists have talked about these things for thousands of years, and I doubt the conversation will end any time soon.

Next, we’ll explore more fully a theme I’ve already touched on in this article: Boyle’s heartfelt commitment to the design argument. After that, we’ll see how Boyle did invoke God’s absolute power in support of experimental science—not as a component of scientific explanations themselves, but to justify doing experiments in the first place.

Early in this article, I said that Boyle’s abiding interest in Christian apologetics reflects the lifelong conversation he had with his own religious doubts. Right in the center of this conversation we find his outspoken advocacy of the design argument for God’s existence. Indeed, considering the depth of his commitment to it, the substantial financial support he provided for others to promote it after his death, and the close resemblance between his attitudes and arguments and those of modern ID advocates, it’s entirely appropriate to see Boyle as the “Father of Intelligent Design.”

Boyle on Design in Nature

As we’ve already seen, Boyle saw the mechanical philosophy as a powerful ally for religion, and the clock metaphor was integral to his apologetics. He found the mechanical philosophy attractive for two nearly opposite reasons. On the one hand, it drew our attention more deeply into nature, by stressing the created mechanisms themselves as the proper subjects of our scientific investigations. On the other hand, it drew our attention away from nature itself, pointing clearly and powerfully to the One who had fashioned it exquisitely as the proper object of our worship.

Thus, Boyle argued that design principles—what Aristotle had called “final causes”— have a proper place within natural philosophy. However, he added a crucial caveat, printed in italics for emphasis: “That the Naturalist should not suffer the Search or the Discovery of a Final Cause of Nature’s Works, to make him Undervalue or Neglect the studious Indagation of their Efficient Causes.” What Aristotle called “efficient causes” were just the actual physical causes at hand. Francis Bacon had offered the same caution decades earlier in The Advancement of Learning. Given that Bacon was a regular part of Boyle’s intellectual diet, it’s safe to assume a specific influence here. Although neglecting efficient causes “would render Physiology [i.e., scientific investigation] Useless,” Boyle added, “the studious Indagation of them, will not Prejudice the Contemplation of Final Causes” (A Disquisition on the Final Causes of Natural Things, in The Works of Robert Boyle, vol. 11, pp. 149-50).

In other words, diligently pursue the physical causes of things, for that’s how science is done; but, at the same time, design is sometimes evident in the whole contrivance one is studying. Indeed, “the Wise Author of Nature has so excellently Contriv’d the Universe, that the more Clearly and Particularly we Discern, how Congruous the Means are to the Ends to be obtain’d by them, the more Plainly we Discern the Admirable Wisdom of the Omniscient Author of Things; of whom it is Truly said by a Prophet, that He is Wonderful in Counsel, and Excellent in Working.” Consequently, neither the present “Fabrick of the Universe” nor the “First Formationof the Universe” could rationally be ascribed to “so Blind a Cause as Chance” (Final Causes, in Works, vol. 11, pp. 150-51, quoting Isa. 28:29).

Throughout his voluminous writings, Boyle insisted that intelligence be invoked as a principle of world-formation; the appeal to “chance” or “nature” alone without God guiding the parts of matter was religiously dangerous. He loved to cite the Presocratic philosopher Anaxagoras as an example of a mechanical philosopher with similar views. Anaxagoras saw nature as an ordered cosmos rather than a random chaos; he stressed the formative influence of an immaterial nous (intellect or mind). In a fascinating unfinished essay, Boyle even described himself as an “Anaxagorean” philosopher to set himself apart from the “Epicurean & such like Attomists who after Leucippus & Democritus ascribe not only the particular effects produc’d in the world but the first formation of the world it selfe to the casual concourse of indivissible Corpuscles of Uncreated Matter moveing from all Eternity in an infinite empty space without takeing in any Diety or other incorporeal substance to sett these Attomes a moveing or regulate their Motions” (Works, vol. 14, pp. 148). Never has there been a more strongly committed proponent of Intelligent Design.

The Boyle Lectures, “Atheists,” and Boyle’s Priestly Role

In truth, Boyle went even further than most contemporary ID advocates. In his view, science did not merely establish the existence of an intelligent designer for the universe and some of its parts; science could actually show the truth of Christianity itself. For this reason, he put a provision in his will to endow a lectureship for “proveing the Christian Religion against notorious Infidels (viz) Atheists, Theists [today we would say “deists”], Pagans, Jews and Mahometans, not descending lower to any Controversies that are among Christians themselves” (Maddison, Life of Boyle, p. 274). The specific language here, uncharacteristically (for Boyle) pointed against Jews and Muslims while characteristically generous toward fellow Christians of all types, was apparently based on a similar phrase from the title page of A Woorke concerning the trewnesse of the Christian Religion(1587), a treatise by Philippe de Mornay that Boyle had read as a young man. Mornay had announced that his book was written “Against Atheists, Epicures, Paynims, Jewes, Mahumetists, and other Infidels.”

The Boyle Lectures began in March 1692, scarcely two months after Boyle’s death, when theologian Richard Bentley spoke in a London church. They continued for forty years before ceasing, but many similar events in subsequent centuries have been called “Boyle Lectures” by their sponsors. In 2004, a group including the current Earl of Cork and Orrery revived them yet again.

Although Boyle often targeted “atheists” in his writings, using that word or a cognate several dozen times, he realized that genuine philosophical atheism was rare in his day. His real targets were the lust, greed, vanity, and open mockery of the Bible exhibited by courtiers and self-styled literary “wits,” the type of people whom he called “practical Atheists,” or “baptized infidels,” who lived as if there were no God to judge them—and here he thought the design argument had its greatest value. As he stated in his book about design, he desired “that my Reader should not barely observe the Wisdom of God, but be in some measure Affectively Convinc’d of it.” Note that he said “affectively,” not “effectively,” a subtlety that we must not overlook: natural theology was a means to make his own intense piety more contagious.

There was no better way, in Boyle’s opinion, to “give us so great a Wonder and Veneration” for God’s wisdom, than “by Knowing and Considering the Admirable Contrivance of the Particular Productions of that Immense Wisdom,” by which he mainly meant the exquisitely fashioned parts of animals both great and small. Thereby, Boyle believed, “Men may be brought, upon the same account, both to acknowledge God, to admire Him, and tothankHim” (Final Causes, in Works, vol. 11, pp. 145 and 195). Surely, this is the ultimate goal of the modern ID movement, despite a certain reluctance to speak openly about God.

For reasons such as these, Boyle unhesitatingly described himself as a “priest of nature” (Christian Virtuoso, II, in Works, vol. 12, p. 490, his italics). He believed it was “an act of Piety to offer up [on behalf of] the Creatures the Sacrifice of Praise to the Creator” (Usefulness of Natural Philosophy, in Works, vol. 3, p. 203). God wanted us “to have his Works regarded & taken Notice of,” Boyle emphasized. From this he inferred that “the study of the Booke of Nature, is one of the Ends of the Institution of the Sabbath,” adding that ‘I scruple not (when Opportunity invites) to spend some [time on the Sabbath] in Studying the Booke of the Creatures, either by instructing my selfe in the Theory of Nature; or trying those Experiments, that may improve my Acquaintance with her” (“Of the Study of the Book of Nature,” in Works, vol. 13, pp. 154-5). No Puritan view of the Sabbath for Boyle, apparently.

Boyle’s Christian beliefs had two further consequences for his science that we will explore in the final parts of this piece.

“What I’m really interested in is whether God could have made the world in a different way; that is, whether the necessity of logical simplicity leaves any freedom at all.” —Albert Einstein (quoted by Holton)

The greatest scientist of the last century, Albert Einstein, never hesitated to express his metaphysical convictions and aesthetic instincts. Neither did Boyle. Indeed, they both wanted to know whether God had any choice when he made the universe, and important aspects of their science reflect this. Einstein’s unabashed rejection of quantum indeterminacy, which he famously summarized by telling Max Born that God “does not throw dice”, is a prime example. For Boyle, the nature of the created order depended on how God had freely chosen to make it, and our limited ability to probe the depths of creation by empirical methods resulted from our status as finite creatures in a world created by a free and omnipotent Creator.

The Limits of Reason in a Freely Created World

Boyle’s modest view of scientific knowledge and its limits was certainly consistent with his laboratory experience, which encouraged humility—a topic I will return to in my next column. However, it was also firmly grounded in his theological beliefs about God, nature, and the human mind. For Boyle, no less than for many other Christian thinkers for two millennia, our ability to understand the creation—what I’ll call the “horizontal” relationship—depended on the two “vertical” relationships: God’s relationship to the human mind and God’s relationship to the created order.

Contrary to what is commonly thought, the Christian doctrine of creation is not primarily about material origins. Rather, it’s about relationships: how God relates to the created world, including us. Graphic by Edward B. Davis.

Boyle took a dim view of those who placed too much stock in reason, vis-à-vis God’s freedom and power. We “mistake and flatter Humane Nature too much, when we think our faculties of Understanding so unlimited, both in point of capacity and of extent, and so free and unprepossest, as many Philosophers seem to suppose.” Despite our high opinion of ourselves, “we are really but created and finite Beings (and that probably of none of the highest orders of intellectual Creatures) and we come into the world, but such, as it pleased the Almighty and most free Author of our Nature to make us.” Our mental abilities are “proportionable to Gods designs in creating us, and therefore may probably be supposed not to be capable of reaching to all kinds … of Truths, many of which may be unnecessary for us to know here,” in this world (Things Above Reason, in The Works of Robert Boyle, vol. 9, pp. 370-1).

In Boyle’s opinion, we are merely “purblind mortals” who can be only “incompetent judges” of God’s power, which “may justly be supposed to reach farther, than our limited intellects can apprehend, or for that reason, without a saucy rashness, can presume to bound.” He was intellectually cautious, concerned that we might place too much confidence in reason, in a world created by a God who is not bound to create things according to our specifications. If God is in fact “the author of things, it is rational to conceive, that he may have made them commensurate, rather to his own designs in them, than to the notions we men may best be able to frame of them.” Indeed, according to Genesis, “the world itself was first made before the contemplator of it, man: whence we may learn, that the author of nature consulted not, in the production of things, with human capacities; but first made things in such manner, as he was pleased to think fit, and afterwards left human understandings to speculate as well as they could upon those corporeal, as well as other things” (Christian Virtuoso, I, Appendix, in Works, vol. 12, pp. 374 and 397-8). In other words, we weren’t around when God made the world, so we didn’t have any input. We can’t presume that God must have done it our way. God did what he wanted, and we can only do our best to figure it out on our own.

Boyle went even further than this in an unpublished manuscript. Imagining what it was like before “the beginning of the Creation,” when there was nothing “besides God himselfe who is Eternall,” Boyle noted that all other beings “must derive there [sic.] natures & all their faculties from his Arbitrary will.” Therefore, “man himselfe” and all other creatures “were but just shuch [such] as he thought fitt to make them,” so God “freely establisht … the Laws of Motion by which the universe was framed, & doth act” (Royal Society, Boyle Papers, vol. 36, fol. 46v). This conception of natural laws, in which regularities and patterns were imposed upon matter by the free choice of a sovereign God, is an example of Boyle’s commitment to theological “voluntarism”. The “voluntarist” God is not bound by any dictates other than his own, and thus “the Laws of Motion, without which the present State and Course of things could not be maintain’d, did not necessarily spring from the Nature of Matter, but depended upon the Will of the Divine Author of things” (Christian Virtuoso, I, in Works, vol. 11, p. 302).

Readers may find this difficult to grasp, so let me say it one more time—no, let Boyle say it himself, in another unpublished manuscript: “The Primordial system of the universe, or the great & Original fabrick of the world; was as to us arbitrarily establisht by God. Not that he created things without accompanying, & as it were regulating, his omnipotence, by his boundless wisdome; & consequently did nothing without weighty reasons: but because those reasons are a priori undiscoverable by us: such as are the number of the fixt stars, the colocation as well as number of the planetary globes, the lines & period of their motion, … the bigness, shapes, & differing longevitys of Living creatures; & many other particulars: of which the onely Reason we can assign, is that it pleasd God at the beginning of things, to give the world & its parts also that disposition. (This may be also applyd to the states of bodys & the rules of motion.)” (Royal Society, Miscellaneous MS 185, fol. 29)

Did God have any choice when he made the world? Absolutely.

Divine Freedom and Multiple Worlds

Operating with a voluntarist conception of nature, it was easy for Boyle to consider the possibility of other worlds, quite different from ours: God simply chose to do things differently there. “Now if we grant with some modern Philosophers, that God has made other Worlds besides this of ours, it will be highly probable that he has there display’d His manifold Wisedom, in productions very differing from those wherein we here admire it.” In that case, “I think it may be probably suppos’d that God may have given peculiar and admirable instances of His inexhausted Wisedom in the Contrivance and Government of Systemes, that for ought we know may be fram’d and manag’d in a manner quite differing, from what is observ’d in that part of the Universe that is known to us” (Of the High Veneration Man’s Intellect Owes to God, in Works, vol. 10, pp. 172-3). The kinds of matter, the laws of motion, and the living creatures might all be highly unlike those in our own world.

It’s interesting that passages from Boyle such as this were overlooked by Stephen Dick, the leading historian of extraterrestrial life and author of the most comprehensive history of the idea of other worlds in the Scientific Revolution. Why? Perhaps he missed them, because Boyle wrote about these things in his theological works, not his scientific works—a distinction that Boyle himself drew. Dick’s book was published thirty years ago, at a time when most historians simply did not consider the possibility that theological ideas could have influenced scientific ideas in ways that were both substantive and positive. But, they did.

For an even more striking example, listen to what Boyle said about the eschaton, the time when God will someday create a new heaven and earth. “And who knows, but that in that new heaven, and new earth, (that is, by an usual Hebraism, that new world) that God will substitute for it, the primordial frames of things, and the laws of motion, and consequently, the nature of things corporeal, may be very differing from those that obtain in the present worlds” (Christian Virtuoso, II, in Works, vol. 12, p. 521). As he said elsewhere, only “God knows particularly both why and how the Universal matter was first contriv’d into this admirable Universe, rather than a World of any other of the numberless Constructions He could have given it; and both why those laws of Motion rather than others were establish’d: and how senseless Matter, to whose Nature Motion does not at all belong, comes to be both put into Motion, and qualifyed to transfer it according to determinate rules, which[matter] it self cannot understand” (Of the High Veneration Man’s Intellect Owes to God, in Works, vol. 10, p. 188).

Boyle’s discussion of contingency and other worlds resonates with the conversation about fine tuning and the multiverse today. I don’t want to double the length of this post, but let me say just this much: we know of no sufficient reason why the physical laws and constants of our universe had to be just as they are. This suggests God’s provision for our world—and for other any inhabited worlds (if they turn out to exist) where the constants aren’t so friendly to creatures like us.

Reason, Experience, and God

To see more fully what Boyle was driving at, let’s contrast his position with that of Galileo. Although he was no less accomplished than Boyle as an experimentalist, Galileo’s view of scientific knowledge was quite different. For Galileo, science should aim for necessary demonstration, akin to mathematical certainty. As he said in his famous book about the Copernican theory, “The Divine intellect indeed knows infinitely more propositions [than we can ever know]. But with regard to those few which the human intellect does understand, I believe that its knowledge equals the Divine in objective certainty, for here it succeeds in understanding necessity, beyond which there can be no greater sureness” (Dialogue Concerning the Two Chief World Systems, p. 103).

Several years earlier, in his great book on the philosophy of science, Galileo penned the following famous passage, in which he lays out his vision for a demonstrative science of nature. When you read it, keep in mind that in his day “philosophy” basically meant what we now call “science.” “Philosophy is written in this grand book—I mean the Universe—which stands continually open to our gaze, but it cannot be understood unless one first learns to comprehend the language and interpret the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles and other geometrical figures, without which it is humanly impossible to understand a single word of it” (The Assayer, pp. 237-8). Reading both of these passages together—which is fair, since both come from the same period in his life and both deal with mathematics—we see what Galileo was driving at: God wrote the book of nature in mathematical language, and when we speak God’s language we can be absolutely certain about our conclusions.

As we’ve seen, Boyle’s conception of scientific knowledge was markedly different. What can we conclude from this comparison? We can’t say that Galileo’s attitude wasn’t an important part of the Scientific Revolution. And, we can still find great scientists today with similar views: Steven Weinberg and Max Tegmark come to mind. Modern science involves a sophisticated interplay of reason and experience; both Galileo and Boyle contributed something essential. What we can say is this: Theological ideas about divine freedom and human reason encouraged an intellectually modest, empirical approach to nature during the Scientific Revolution—just as different theological ideas encouraged a more deductive approach. The common picture of ongoing, inevitable conflict between science and religion is not only false, but perverse, for it prevents us from seeing the kinds of deep connections I’ve shown here.

I’m hardly alone in saying this. Eighty years ago, philosopher Michael Beresford Foster put forth the abstract philosophical claim that theological voluntarism must have had consequences for conceptions of nature and scientific method in this period, since almost all of the scientists at that time were Christian theists. Foster did very little to show that this was actually true historically, but in recent decades several prominent historians have shown that he was at least partly correct. Some of the best-known scholars in this category are John Hedley Brooke,John Henry, the late Reijer Hooykaas, J. E. (“Ted”) McGuire, Francis Oakley, and the late Margaret J. Osler. Taken together, their work goes a long way toward bridging the gap between Foster’s abstract assumptions and the complex historical reality of early modern science.

Theology mattered. It still does.