by Dan Falk
By Shakespeare’s day, the metaphor was ubiquitous: Nature was seen as a book that could be read by someone with the right training. We have some idea of the texts that the playwright perused, and he almost certainly had access to an encyclopedia written by a Frenchman named Pierre de la Primaudaye, who declares that we must consult both “books” in order to know God: “We must lay before our eyes two bookes which God hath given unto us to instruct us by, and lead us to the knowledge of himselfe, namely the booke of nature, and the booke of his world.” Mind you, Shakespeare wasn’t shy about projecting the metaphor back to ancient Rome. In Antony and Cleopatra, the soothsayer says of his abilities: “In nature’s infinite book of secrecy / A little I can read” (1.2.10–11).
Two books, but a common purpose: to know the mind of God, and through God to understand the meaning and purpose of life. As a new era dawned, Lawrence Principe writes, the greatest of thinkers “looked out on a world of connections and a world full of purpose and meaning as well as of mystery, wonder, and promise.”
FROM MEDIEVAL TO MODERN
A profound change in this way of seeing the world was on the horizon—though of course no one at the time would have recognized its first stirrings. The period that we now think of as the Scientific Revolution—roughly 1500 to 1700—was seen as nothing of the sort at that time. Moreover, the discoveries that we celebrate in science museums today probably had little impact on ordinary men and women at the time. As Peter Dear observes, it is “unclear how much difference the classic ‘Scientific Revolution’ of the sixteenth and seventeenth centuries made to ordinary people.” The innovations that it brought “left most features of their everyday lives unchanged.” As Steven Shapin points out, the term “Scientific Revolution” saw widespread use beginning only in the late 1930s.* (It has been fashionable in recent years to quote the first sentence of Shapin’s book The Scientific Revolution: “There was no such thing as the Scientific Revolution. And this is a book about it.”) And yet it was, undeniably, a time of unprecedented inquiry, investigation, and discovery.
Whatever we may call this period, something rather important happened, even if it was more gradual, and constituted less of a break with past traditions, than the name “revolution” might suggest. But it did not come out of the blue; rather, it was built on a foundation established in the latter part of the Middle Ages. And it did not happen everywhere at the same time; what we would now recognize as “modern” developments in medicine, engineering, and commerce, as well as in the visual arts and literature, could be seen in Italy many decades before they reached more remote parts of the Continent. It was, as Principe puts it, “a rich tapestry of interwoven ideas and currents, a noisy marketplace of competing systems and concepts, a busy laboratory of experimentation in all areas of thought and practice.” The printing press, a fifteenth-century invention, fostered the spread of ideas at a new, accelerated pace, while voyages of discovery were opening up new worlds for colonization and exploitation. And the rediscovery of classical texts, via Arabic translations, triggered a new wave of learning across Europe. Those works included the writings of Aristotle and Ptolemy, which we’ve touched on, as well as the geometry of Euclid, the medical writings of Galen, and much more.
This wave of learning was closely linked to the activities of the Roman Catholic Church. The best medieval schools had been those associated with the monasteries and the great cathedrals. By the late Middle Ages these had also become centers of what we would now call science (as mentioned, at that time such pursuits would have fallen under the umbrella of natural philosophy). There were also the universities, the earliest having been founded around 1200; these, too, functioned largely as religious institutions. The highest degree offered was in theology—though to obtain it, the student also had to master mathematics, logic, and natural philosophy.
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This close connection between science and faith may seem strange to the modern reader, living at a time when Western society, and Western science in particular, has become a secular endeavor—and with best-selling authors declaring religion to be antithetical to science and an obstacle to progress. The evolving relationship between science and religion is a large and complex subject, but one thing is clear: Whatever that relationship may be like today, it was very different four hundred years ago. There was no “conflict” between science and religion for the simple reason that no such division between the two pursuits existed. For one thing, religion was simply part of the fabric of society; all of the key figures of the Scientific Revolution were men of faith of one kind or another. (These days Francis Bacon is hailed as one of the founders of modern science—but a first-time reader of his Advancement of Learning [1605] might be surprised to find that he expounds at some length on God and the Bible.) Moreover, the very thing being investigated—the heavens—was seen as indisputable evidence of God’s craftsmanship. Robert Recorde, writing in the middle of the sixteenth century, is typical in his enthusiasm. His Castle of Knowledge is at once a textbook on astronomy and an expression of religious devotion. He begins:
Oh worthy temple of Gods magnificence. Oh throne of glory and seate of the Lord: thy substance most pure what tongue can describe? Thy beauty with stares so garnished and glittering … Oh marvellous Maker, oh God of good governance: thy works are all wonderous, thy cunning unknowen: yet seeds of all knowledge in that booke are sowen.…
To study astronomy was to study “the book of nature”; it could not fail to lead one to a greater understanding of God. As Recorde assured his readers, “there was never any good astronomer that denied the majestie and providence of God.” As historian Paul Kocher puts it, early modern science “was more often cited as proving God’s existence than disproving it, under the staple argument that study of the marvellous structure of the universe led man’s mind to see that it must have had a Creator.” And as Principe writes, the study of nature was seen as “an inherently religious activity.” The twenty-first-century notion that scientific investigation requires checking one’s faith at the door is a much more modern idea, one that would have been incomprehensible to the great thinkers of this time.
But the link between science and faith, as Principe stresses, is deeper than this. For the thinkers of early modern Europe, he writes, “the doctrines of Christianity were not personal choices. They had the status of natural or historical facts”:
Never was theology demoted to the status of “personal belief”; it constituted, like science today, both a body of agreed-upon facts and a continuing search for truths about existence.… Thus theological ideas played a major part in scientific study and speculation—not as external “influences,” but rather as serious and integral parts of the world the natural philosopher was studying.
This is a useful reminder, because it is commonplace today to pick up a weekly newsmagazine and read of religious thinkers being “influenced” by science or, less frequently, of a scientific idea having been influenced by religious thought (the big-bang-model theory of modern cosmology comes to mind). The presumption is that science is a kind of monolithic, ever-expanding pool of wisdom, with religion (and philosophy) merely coming along for the ride. Whatever we think of this view today, it would have been meaningless in early modern Europe. The so-called war between science and religion was largely an invention of the late nineteenth century, and, while it may have some relevance today, Principe is correct to remind us that it “does not portray the historical situation.”*
Perhaps the clearest example of the interdependence of science and faith during the late Middle Ages, and into the Renaissance, comes from the field we have been discussing: astronomy. Religious leaders relied on the work of astronomers to determine the date of Easter, the holiest day in the Christian calendar. The date of Easter was calculated by means of a complex algorithm that depended on the date of the vernal equinox—the day when the hours of daylight exactly equal the hours of darkness, marking the first day of spring. But determining the date of the equinox is i
tself a difficult problem, and can only be worked out through careful observations of the heavens. To aid in this work, dozens of churches and cathedrals across Christian Europe also served as observatories; many were equipped with strategically placed apertures in walls or ceilings that allowed a beam of sunlight to strike a north-south “meridian line” on the floor. The resulting measurements helped establish the dates of the solstices and equinoxes, on which the Easter calculations depended. And so the Roman Catholic Church was, for many centuries, the largest sponsor of astronomical research in Europe.†
It is hardly a surprise, then, that many of the natural philosophers of the early modern era were also churchmen of one kind or another. That is certainly the case with the pious Catholic cleric from the remote eastern edge of Europe who, early in the sixteenth century, decided that studying the heavens might be just as rewarding as studying the intricacies of ecclesiastical law. He would soon turn the universe on its head.
2. “He that is giddy thinks the world turns round…”
NICOLAUS COPERNICUS, THE RELUCTANT REFORMER
We know precious little about the man who overturned a millennium and a half of astronomical thinking. The portrait that hangs in the town hall in Toruń, the city of his birth, shows Nicolaus Copernicus as a slim, hollow-cheeked man sporting a red jerkin and thick, wavy, jet-black hair. His dark, piercing eyes gaze not ahead but sharply to his left, as though someone or something out of the frame demanded his attention. It reveals little of his personality. We do know that he was born in 1473, the son of a wealthy merchant. The city of Toruń was, at that time, part of Royal Prussia (encompassing those Prussian districts which fell under the control of the king of Poland). His family, however, spoke German, and in his youth he went by the name Niklas Koppernigk.* Copernicus did much of his studying abroad, which explains his decision to adopt a Latinized name. He studied first in Cracow and later in Bologna, where he focused on canon law (the laws governing the rights and responsibilities of Church leaders). He also became a committed humanist.† After the death of his father, his education and travels were supported by his maternal uncle, a powerful bishop. Copernicus returned to his homeland in 1497, where his uncle appointed him as a canon (more than an administrator but less than a priest) at Frauenburg Cathedral (today Frombork Cathedral), in the province of Warmia on the Baltic Sea. Copernicus’s ecclesiastical ambitions seem to have stopped short of full-fledged priesthood, and it is likely that he was never ordained. He would later return to Italy, enrolling as a medical student at Padua, returning to Frauenburg after his graduation, in 1510.
Of his personal life, however, we remain ignorant; the documentation is simply absent. Owen Gingerich, the astronomer and historian of science who probably knows Copernicus better than any scholar today, admits defeat on the question of Nicolaus’s personality:
What sort of person was Copernicus? Did he like puns? Did he ever play jokes on his classmates or his fellow canons? Did he enjoy music?… Did he ever have a girlfriend? Did he like children? Alas, these are unanswerable questions.
We do know that Copernicus became captivated by astronomy at an early age, though we can’t say exactly when this fascination began. He was likely exposed to the Ptolemaic model during his time at Cracow. In Bologna, he assisted a well-known astronomer named Novara, observing an occultation of the star Aldebaran by the moon in the spring of 1497 (when he was twenty-four); three years later he observed a partial lunar eclipse from Rome.*
SEEKING HIDDEN CAUSES
By the time of his studies in Italy, Copernicus was likely familiar with the shortcomings of the Ptolemaic system. Once he settled in Frauenburg, where he would remain for the final four decades of his life, he devoted nearly all of his energy to studying the heavens and improving the description of how celestial bodies moved. He had an observing tower added to the wall surrounding the cathedral; visitors can see it to this day. With damp fog often rolling in from the mouth of the Vistula River, however, it was not an ideal location. (“The ancients had the advantage of a clearer sky,” he admitted.) At first, he told only his closest confidants of his ideas, but to those who knew him, it was clear that he was up to something. As a colleague observed, “He discusses the swift course of the Moon and [the sun] as well as the stars together with the wandering planets … he knows how to seek out hidden causes of phenomena by the aid of wonderful principles.” It is also worth noting that in an age when most people believed in astrology, Copernicus apparently did not.
As we’ve seen, the Ptolemaic system did not lack for accuracy; and its picture of a stationary Earth, with the heavens whirling around, was compatible with the commonsense view of the cosmos. So what drove Copernicus to challenge the established model of the heavens? There is probably more than one answer—but an important element is Copernicus’s commitment to the Platonic ideal of circular motion, which he saw as the only conceivable motion that a heavenly body would execute; and his belief that a planet must move at a constant speed along these circles. Recall that in Ptolemy’s system, the planets were seen to move at a constant speed only relative to an imaginary point, the equant. To Copernicus, this seemingly arbitrary invention was at odds with the spirit of Plato’s vision; it was “neither sufficiently absolute nor sufficiently pleasing to the mind.” Copernicus offered an alternative model: Perhaps the sun, not the Earth, lay at the center of the observed motions. As early as 1510, he realized that, with this simple switch, he could construct a system in which the planets moved with truly uniform, circular motion. This seems to have been his first concern; the new structure—heliocentric (sun-centered) rather than geocentric (Earth-centered)—was perhaps secondary. Yet once he had made the switch, he became enamored with it. “All the spheres revolve about the sun as their mid-point,” he would write, “and therefore the sun is the center of the universe.” There was no going back.*
As it happens, Copernicus was not the first to propose a heliocentric model; it had been put forward by Aristarchus of Samos (ca. 310–230 B.C.) and by a handful of other ancient Greek astronomers. However, no one had worked out the details of the theory and the idea seems to have been abandoned. (Indeed, there is no evidence that Copernicus was aware of Aristarchus’s writings on heliocentrism, which had not yet appeared in Latin translation.) And so the idea began its revival when Copernicus penned a short manuscript outlining the “new” theory. This text, from about 1510, is known as the Commentariolus (The Little Commentary).
This was the first ripple in the slow but inevitable spread of Copernicus’s theory. Nearly half a century would pass before anyone in England took note; this would come with the publication of Robert Recorde’s The Castle of Knowledge in 1556. Shakespeare, born just eight years later, entered a world in which the heliocentric model was still young and tentative; as we will see, however, it became less tentative with each passing decade. Yet its first mention was more like a whisper: The Commentariolus was not published in Copernicus’s lifetime, and only a handful of manuscript copies are believed to have circulated. In fact, if word of the new theory hadn’t reached a young German astronomer named Georg Joachim Rheticus, history might have unfolded quite differently. Rheticus was so taken by the heliocentric model that he set off to Frauenburg to meet its author in person. He would become Copernicus’s sole pupil.
Copernicus, meanwhile, was becoming more and more convinced that Ptolemy’s system was too inelegant to represent the true structure of the heavens. With its hodgepodge of epicycles, Ptolemy’s depiction seemed downright ugly. The astronomers who supported it “have been like someone attempting a portrait by assembling hands, feet, head, and other parts from different sources,” he wrote. “These several bits may be well painted, but they do not fit together to make a single body. Bearing no genuine relationship to each other, such components, joined together, would compose a monster, not a man.”
Contrary to popular myth, Copernicus’s model was not “simpler” than that of Ptolemy in any objective sense, as we shall see. And
yet, a sun-centered system did manage to solve many of the problems that had challenged astronomers from the beginning. For starters, it presented a simple explanation for the observed retrograde motion the planets sometimes displayed. Consider the case of Mars: As the faster-moving Earth passes or “laps” the slower-moving red planet, it appears to temporarily reverse its direction, as seen against the background stars. (This instantly made the largest set of epicycles in the Ptolemaic system redundant.) Secondly, the new model gave a straightforward explanation for why Mercury and Venus always seem to lie close to the sun in the sky (namely: they really are close to the sun). It solved a third problem as well: The planets were seen to vary in brightness over a period of weeks and months. In the new system, the Earth was in motion; as it moved in its orbit, it was sometimes closer to a particular planet, and sometimes farther away. The changing brightness of the planets now made perfect sense. By simplifying these issues, the Copernican model could be seen as a simpler way of describing the motion of the planets; it required fewer hypotheses and fewer arbitrary assumptions. As Copernicus noted, he chose to “follow the wisdom of nature, which, as it takes very great care not to have produced anything superfluous or useless, often prefers to endow one thing with many effects.”*