Having set down a first version of his thesis in a short manuscript, the Commentariolus, Copernicus circulated it among his friends as early as 1514. Two decades later, a lecture on the principles of his new system was given in Rome before the pope, who approved. Subsequently, a formal request to publish was made. Yet throughout most of his life, Copernicus held back from full publication of his extraordinary idea. (Later, in his preface to the De Revolutionibus, dedicated to the pope, Copernicus confessed his reluctance to reveal publicly his insight into nature’s mysteries lest it be scorned by the uninitiated—invoking the Pythagorean practice of strict secrecy in such matters.) But his friends and particularly his closest student, Rheticus, prevailed upon him, and finally Rheticus was allowed to take the completed manuscript from Poland to Germany to be printed. On the last day of his life, in the year 1543, a copy of the published work was brought to Copernicus.
But on that day, and even during the following several decades, there was little indication in Europe that an unprecedented revolution in the Western world view had been initiated. For most who heard of it, the new conception was so contradictory to everyday experience, so patently false, as not to require serious discussion. But as a few proficient astronomers began to find Copernicus’s argument persuasive, the opposition began to mount; and it was the religious implications of the new cosmology that quickly provoked the most intense attacks.
The Religious Reaction
In the beginning, that opposition did not come from the Catholic Church. Copernicus was a canon in good standing at a Catholic cathedral and an esteemed consultant to the Church in Rome. His friends urging publication included a bishop and a cardinal. After his death, Catholic universities did not avoid using the De Revolutionibus in astronomy classes. Moreover, the new Gregorian calendar instituted by the Church was based on calculations according to Copernicus’s system. Nor was this apparent flexibility altogether unusual, for throughout most of the high Middle Ages and Renaissance, Roman Catholicism had allowed considerable latitude in intellectual speculation. Indeed, such latitude was a major source of Protestant criticism of the Church. By tolerating and even encouraging the exploration of Greek philosophy, science, and secular thinking, including the Hellenistic metaphorical interpretation of Scripture, the Church had, in Protestant eyes, allowed pristine Christianity and the literal truth of the Bible to be contaminated.
It was antagonism from the Protestant reformers that arose first and most forcefully, and understandably so: the Copernican hypothesis contradicted several passages in Holy Scripture concerning the fixity of the Earth, and Scripture was Protestantism’s one absolute authority. To have biblical revelation questioned by human science was just the kind of Hellenizing intellectual arrogance and interpretive sophistry the reformers most abhorred in Catholic culture. Protestants were therefore quick to recognize the threat of Copernican astronomy and condemn the impiety. Even before the publication of the De Revolutionibus, Luther called Copernicus an “upstart astrologer” who foolishly wished to reverse the entire science of astronomy while flagrantly contradicting the Holy Bible. Luther was soon joined by other reformers like Melanchthon and Calvin, some of whom recommended that stringent measures be taken to suppress the pernicious heresy. Quoting a passage from the Psalms, “the world also is established, that it cannot be moved,” Calvin asked: “Who will dare to place the authority of Copernicus above that of the Holy Spirit?” When Rheticus took Copernicus’s manuscript to Nürnberg to be published, he was forced by reformers’ opposition to go elsewhere. Even in Leipzig, where he left the book with the Protestant Osiander to publish, the latter inserted an anonymous preface without Copernicus’s knowledge, asserting that the heliocentric theory was merely a convenient computational method and should not be taken seriously as a realistic account of the heavens.
The ploy may have saved the publication, but Copernicus had indeed been serious, as a close reading of the text revealed. And by Galileo’s time in the early seventeenth century, the Catholic Church—now with a renewed sense of the need for doctrinal orthodoxy—felt compelled to take a definite stand against the Copernican hypothesis. While in an earlier century, Aquinas or the ancient Church fathers might have readily considered a metaphorical interpretation of the scriptural passages in question, thereby eliminating the apparent contradiction with science, the emphatic literalism of Luther and his followers had activated a similar attitude in the Catholic Church. Both sides of the dispute now wished to secure an uncompromised solidity with respect to the biblical revelation.
Moreover, guilt by association had recently hurt the reputation of Copernicanism in the case of the mystical Neoplatonist philosopher and astronomer Giordano Bruno. Bruno had widely promulgated an advanced version of the heliocentric theory as part of his esoteric philosophy, but had later been tried and executed by the Inquisition for heretical theological views. His stated beliefs that the Bible should be followed for its moral teachings rather than its astronomy, and that all religions and philosophies should coexist in tolerance and mutual understanding, had received little enthusiasm from the Inquisition. In the heated atmosphere of the Counter-Reformation, such liberal views were unwelcome at best, and in the case of Bruno, whose character was as refractory as his ideas were unorthodox, they were scandalous. Certainly the fact that the same man who held heretical views on the Trinity and other vital theological matters had also taught the Copernican theory did not augur well for the latter. After Bruno was burned at the stake in 1600 (though not for his heliocentric teachings), Copernicanism seemed a more dangerous theory—both to religious authorities and to philosopher-astronomers, each for their different reasons.
Yet not only did the new theory conflict with parts of the Bible, it was now apparent that Copernicanism posed a fundamental threat to the entire Christian framework of cosmology, theology, and morality. Ever since the Scholastics and Dante had embraced Greek science and endowed it with religious meaning, the Christian world view had become inextricably embedded in an Aristotelian-Ptolemaic geocentric universe. The essential dichotomy between the celestial and terrestrial realms, the great cosmological structure of Heaven, Hell, and Purgatory, the circling planetary spheres with angelic hosts, God’s empyrean throne above all, the moral drama of human life pivotally centered between spiritual heavens and corporeal Earth—all would be cast into question or destroyed altogether by the new theory. Even discounting the elaborate medieval superstructure, the most basic principles of the Christian religion were now being impugned by the astronomical innovation. If the Earth truly moved, then no longer could it be the fixed center of God’s Creation and his plan of salvation. Nor could man be the central focus of the cosmos. The absolute uniqueness and significance of Christ’s intervention into human history seemed to require a corresponding uniqueness and significance for the Earth. The meaning of the Redemption itself, the central event not just of human history but of universal history, seemed at stake. To be a Copernican seemed tantamount to atheism. In the eyes of the papal advisors, Galileo’s Dialogue Concerning the Two Chief World Systems, already being applauded throughout Europe, threatened to have worse effects on Christian minds “than Luther and Calvin put together.”
With religion and science in such apparent contradiction—and an upstart science at that, a mere novel theory—there was little question for Church authorities as to which system would prevail. Awakened to the dire theological implications of Copernican astronomy, and further traumatized into dogmatic rigidity by decades of Reformation conflict and heresy, the Catholic Church mustered its considerable powers of suppression and condemned in no uncertain terms the heliocentric hypothesis: the De Revolutionibus and Dialogue placed on the Index of forbidden books; Galileo interrogated by the Inquisition, forced to recant and placed under house arrest; major Catholic Copernicans dismissed from their posts and banished; all teachings and writings upholding the motion of the Earth prohibited. With the Copernican theory, Catholicism’s long-held tension between reason
and faith had finally snapped.
Kepler
But by the time of Galileo’s recantation, the scientific triumph of Copernicanism was already in sight, and the attempts to suppress it by the institutional religions, both Catholic and Protestant, would soon turn against them. Nevertheless, in the early years of the heliocentric theory that triumph did not seem assured. The notion of a moving Earth was generally ridiculed, if noticed at all, by Copernicus’s contemporaries and throughout the rest of the sixteenth century. Moreover, the De Revolutionibus was obscure enough (perhaps intentionally) and so demanding of technical mathematical proficiency that only a few astronomers could understand it, and even fewer could accept its central hypothesis. But neither could they overlook its technical sophistication, and its author was soon referred to as “a second Ptolemy.” During the following decades, increasing numbers of astronomers and astrologers found Copernicus’s diagrams and computations useful, even indispensable. New astronomical tables based on more recent observations were published employing his methods, and as these tables were measurably superior to the old ones, the reputation of Copernican astronomy was further enhanced. Yet major theoretical problems still remained.
For Copernicus was a revolutionary who had maintained many traditional assumptions that worked against the immediate success of his hypothesis. In particular, he had continued to believe in the Ptolemaic dictum that the planets must move with uniform circular motion, which forced his system finally to have as much mathematical complexity as Ptolemy’s. For his theory to match the observations, Copernicus still required minor epicycles and eccentrics. He still retained the concentric crystalline spheres moving the planets and stars, as well as other essential physical and mathematical components of the old Ptolemaic system. And he had not adequately answered obvious physical objections to a moving Earth, such as why terrestrial objects would not simply fall off the Earth as it swept through space.
Despite the radical quality of the Copernican hypothesis, a planetary Earth was the only major innovation in the De Revolutionibus, a work that was otherwise solidly within the ancient and medieval astronomical tradition. Copernicus had caused the first break from the old cosmology, and thereby created all the problems that had to be solved by Kepler, Galileo, Descartes, and Newton before they could offer a comprehensive scientific theory capable of integrating a planetary Earth. As Copernicus had left it—a moving Earth in a cosmos otherwise ruled by Aristotelian and Ptolemaic assumptions—there were too many internal contradictions. And because of its adherence to uniform circular motion, Copernicus’s system was finally no simpler or even more accurate than Ptolemy’s. Yet despite the remaining problems, the new theory possessed a certain harmonious symmetry and coherence that appealed to a few subsequent astronomers—most significantly, Kepler and Galileo. It was above all not utilitarian scientific accuracy but aesthetic superiority that would attract those crucial supporters to the Copernican cause. Without the intellectual bias created by a Neoplatonically defined aesthetic judgment, the Scientific Revolution might well not have occurred, certainly not in the form it took historically.
For Kepler, with his passionate belief in the transcendent power of numbers and geometrical forms, his vision of the Sun as the central image of the Godhead, and his devotion to the celestial “harmony of the spheres,” was yet more impelled by Neoplatonic motivations than Copernicus. Writing to Galileo, Kepler invoked “Plato and Pythagoras, our true preceptors.” He believed that Copernicus had intuited something greater than the heliocentric theory was presently capable of expressing, and that, if freed from the Ptolemaic assumptions still resident in the De Revolutionibus, the Copernican hypothesis would open up scientific understanding to a new, spectacularly ordered and harmonious cosmos that would directly reflect God’s glory. Kepler was also the inheritor of a vast body of unprecedentedly accurate astronomical observations collected by Tycho de Brahe, his predecessor as imperial mathematician and astrologer to the Holy Roman Emperor.1 Armed both with these data and with his unwavering faith in the Copernican theory, he set out to discover the simple mathematical laws that would solve the problem of the planets.
For almost ten years, Kepler laboriously attempted to fit against Brahe’s observations every possible hypothetical system of circles he could devise, focusing particularly on the planet Mars. After many failures, he was forced to conclude that some geometrical figure other than the circle must be the true form of planetary orbits. Having mastered the ancient theory of conic sections developed by Euclid and Apollonius, Kepler at last discovered that the observations precisely matched orbits shaped as ellipses, with the Sun as one of the two foci, and with each planet moving at speeds varying proportionately according to its distance from the Sun—fastest near the Sun, slowest away from the Sun, with equal areas swept out in equal times. The Platonic dictum for uniformity of motion had always been interpreted in terms of measurement along the arc of the circular orbit—equal distance on the arc in equal intervals of time. This interpretation had ultimately failed, despite the ingenuity of astronomers for two thousand years. Kepler, however, discovered a new and subtler form of uniformity which did fit the data: If a line were drawn from the Sun to the planet on its elliptical orbit, that line would sweep out equal areas of the ellipse in equal intervals of time. Subsequently, he conceived and corroborated a third law, which demonstrated that the different planetary orbits were exactly related to each other by mathematical proportions—the ratio of the squares of the orbital periods being equal to the ratio of the cubes of their average distance from the Sun.
Thus Kepler at last solved the ancient problem of the planets and fulfilled Plato’s extraordinary prediction of single, uniform, mathematically ordered orbits—and in so doing vindicated the Copernican hypothesis. With elliptical orbits replacing the Ptolemaic circles, and with the law of equal areas replacing that of equal arcs, he was able to dispense with all the complex corrective devices, epicycles, eccentrics, equants, and so forth. Even more significantly, his one simple geometrical figure and his one simple mathematical speed equation produced results that precisely matched observations of the most rigorous quality—something none of the previous Ptolemaic solutions, despite all their ad hoc devices, had ever accomplished. Kepler had taken centuries of diverse and largely inexplicable observations of the heavens and condensed them into a few concise, overarching principles which gave convincing evidence that the universe was arranged in accordance with elegant mathematical harmonies. Empirical data and abstract mathematical reasoning at last meshed perfectly. And of particular importance for Kepler, the most advanced scientific conclusions affirmed both Copernicus’s theory and the mathematical mysticism of the ancient Pythagorean and Platonic philosophers.
Moreover, for the first time a mathematical solution to the problem of the planets led directly to a physical account of the heavens in terms of a physically plausible motion. For Kepler’s ellipses were continuous straightforward motions of a single shape. By contrast, the complicated Ptolemaic system of indefinitely compounded circles possessed no empirical correlate in everyday experience. Because of this, mathematical solutions in the Ptolemaic tradition had often been considered as merely instumentalist constructions with no ultimate claim to describing a physical reality. Copernicus had nevertheless argued for the physical reality of his mathematical constructions. In the first book of the De Revolutionibus, he alluded to the ancient conception of astronomy as “the consummation of mathematics.” Yet in the end, even Copernicus offered an implausibly complicated system of minor epicycles and eccentrics to account for the appearances.
With Kepler, however, Copernicus’s intuition and imperfect mathematical argument were brought to fruition. For the first time in planetary astronomy, the appearances were “genuinely” saved, not just instrumentally. Indeed, Kepler both saved the phenomena in the traditional sense and “saved” mathematical astronomy itself by demonstrating mathematics’ genuine physical relevance to the heavens—its capacity to d
isclose the actual nature of the physical motions. Mathematics was now established not just as an instrument for astronomical prediction, but as an intrinsic element of astronomical reality. Kepler thus considered that the Pythagorean claim for mathematics as the key to cosmic understanding had been triumphantly validated, thereby revealing the previously hidden grandeur of God’s creation.
Galileo
With Kepler’s breakthrough, the Copernican revolution would in time have almost certainly succeeded in the scientific world through sheer mathematical and predictive superiority. But coincidentally, in 1609, the same year that Kepler published in Prague his laws of planetary motion, Galileo in Padua turned his recently constructed telescope to the heavens, and through his startling observations made available to astronomy the first qualitatively new evidence it had known since the ancients. And each of his observations—the craters and mountains on the surface of the Moon, the moving spots on the Sun, the four moons revolving around Jupiter, the phases of Venus, the “unbelievably” numerous individual stars of the Milky Way—was interpreted by Galileo as powerful evidence in favor of the Copernican heliocentric theory.
Passion of the Western Mind Page 33