The scientific revolution Copernicus The scientific revolution was the final contribution of the Renaissance as well as the definitive contribution to the modern worldview. Born in Poland and educated in Italy, Copernicus lived in the height of the Renaissance. Although his contribution was central to our modern psyche, it was not something anyone during the Renaissance could imagine. Copernicus’ contribution symbolized the fundamental break between the ancient and medieval worldview on the one hand and the modern worldview on the other. Copernicus sought to find a solution to the age-old problem of the planets: how to explain the erratic planetary movements by means a simple, clear, and elegant mathematical formula. To recapitulate the solutions proposed by Ptolemy and his successors based on a geocentric Aristotelian cosmos had required the employment of numerous mathematical devices (deferents, major and minor epicycles, equants, eccentrics) in an effort to make sense of the observed positions while maintaining the ancient rule of uniform circular motion. When a planet’s movement did not appear to move in a perfect circle, another smaller circle was added around which the planet hypothetically moved which it continued moving around the larger circle. Further discrepancies were resolved by compounding the circles, displacing their centers, positing yet another center from which motion remained uniform, and so on. Each new astronomer faced with newly revealed irregularities that contradicted the basic scheme attempted to resolve them by adding more refinements – another minor epicycle, another eccentric.
By the time of the Renaissance, the Ptolemaic system had produced what Copernicus called “a monster” that still failed to predict planetary positions with any accuracy. The original Ptolemaic model no longer existed; different Greek, Arabic, and European astronomers using different methods and principles, different combinations of epicycles, eccentrics and equants added a multiplicity of systems to the original Ptolemaic one. The science of astronomy was riddled with uncertainty such that it seemed to Copernicus that no modification of the systems would ever yield predictions of any worth Hence Copernicus assumed that the Ptolemaic system contained an essential error.
Renaissance Europe, especially the church, required a new calendar which in turn depended on astronomical precision. Copernicus was asked to advice the pope on the problem and he told that the current Ptolemaic system was irreparable. Copernicus’ technical and mathematical proficiency led him to see the inadequacies of the current system. Any other astronomer might have concluded the problem was too complex to resolve, but Copernicus’ participation in the Renaissance revival (over Aristotle who dominated medieval science, philosophy, and theology) of neo-Platonism and Pythagoreanism encouraged him to see the problem in terms that ultimately must conform to a simple, harmonious mathematical and transcendental (eternal) quality which pressed him to innovation. The divine Creator whose works where everywhere good and orderly could not have made the heavens slipshod. So Copernicus carefully reviewed the ancient scientific literature\ which had become available during the Renaissance in the humanist revival of Greek manuscripts from Constantinople to the West. He noted that there were several Greek philosophers, of Platonic and Pythagorean background who had suggested that the earth moved although none of them had proposed a mathematical hypothesis to accommodate this suggestion – and Aristotle’s geocentric cosmos remained their core assumption. Armed with these early suggestions of the moving earth and Plato’s exalted sun, along with the Scholastics’ critical appraisal of Aristotle, Copernicus hypothesized a sun-centered universe with a planetary earth, and then worked out the mathematical implications.
Despite the innovation’s apparent absurdity (after all, this is not what our senses tell us) Copernicus arrived at a system qualitatively much better than Ptolemy. The heliocentric model readily explained the daily movements of the heavens, the annual motion of the sun as due to the earth’s daily rotation on its axis and its annual revolution around the sun. The deceptive appearance of the moving sun/stars was now seen as due to the earth’s own movements. The great celestial motions were therefore nothing but a projection of the earth’s motion moving in the opposite direction. To the traditional objection that a moving earth would be disruptive to itself, Copernicus countered that the geocentric theory necessitated an even shifter movement by the immensely greater heavens which would constitute a worse disruption.
Many particular problems that had beset the geocentric tradition seemed suddenly and elegantly solved by Copernicus hypothesis. The apparent backward and forward movements of the planets relative to the fixed stars as well as their varying degrees of brightness (which traditional astronomers had struggled hard to account for mathematically) could now be understood simply as viewing those planets from a moving earth (without any need for epicycles). A moving earth would automatically make regular planetary orbits around the sun appear to a terrestrial observer as irregular movements around the earth. Nor were equants necessary, a device that Copernicus found aesthetically unpleasing because it violated the idea of uniform circular motion. Copernicus’ new ordering of the planets outward from the sun – Mercury, Venus, Earth and Moon, Mars, Jupiter, and Saturn – replaced the traditional earth centered order, and provided a simple and coherent solution to the previously ill-solved problem of why Mercury and Venus always appeared close to the sun. The explanation of these problems and others like them strongly suggested to Copernicus the superiority of the heliocentric over the geocentric theory. The appearances were saved (approximately) and with greater conceptual elegance. Despite the obvious commonsense evidence to the contrary, not to mention 2000 years of scientific tradition, Copernicus was convinced the earth truly moved.
Having set out his theory in a short paper (Commentariolus) which Copernicus circulated among his friends as early as 1514 (about the time of Luther’s Reformation), it was to be another 20 years before he placed it before the pope, who approved. Subsequently, he made a formal request to publish it. Yet throughout his life Copernicus held back full publication – reminiscent of the secrecy characteristic of the Pythagorean tradition – on risk to offending and receiving the scorn of the uninitiated (see his Foreword to De Revolutionibus). Rheticus, Copernicus’ student, however urged him to publish it and Copernicus allowed Rheticus to take the paper from Poland to Germany where it was published. In 1543 (the last day of Copernicus life) Copernicus received a finally published copy.
Of course there was little indication at the time of the nature of Copernicus’ revolution. Even for those who heard of it, it was so contrary to experience, so patently false, that it received no serious discussion. Yet a few astronomers were finding his arguments persuasive, and opposition began to mount as the new religious implications for his cosmology became better known in the decades to follow.
Religious reaction Reaction to Copernicus’ revolution did not originally come from the church. Copernicus was a
Canon in good standing at the RC cathedral and he was an esteemed consultant to the church in Rome. His friends who urged publication included a Bishop and Cardinal. After his death the RC universities used the De Revolutionibus as a text. The new Gregorian calendar instituted by the church was based on Copernicus’ heliocentric system. Of course, none of this was remarkable as the RC church had throughout the Middle Ages and Renaissance allowed considerable latitude in intellectual speculation. In fact, this latitude was part of the basis of Protestant criticism of the church. By tolerating and even encouraging the exploration of Greek philosophy, science, and secular thinking, including Hellenistic metaphorical interpretation of Scripture, the church had at least in Protestant eyes, allowed pristine Christianity and the literal truth of the Bible to become contaminated.
It was therefore Protestant reformers who first opposed the theory: the Copernican hypothesis contradicted biblical text concerning the fixity of the earth, and of course the Bible was the protestant sole authority. To have Scriptural revelation questioned by science was clear evidence of Hellenistic (Plato/Pythagoras) intellectual arrogance that the reformers abhorred most in the RC church. Protestants were therefore quick to recognize the threat of Copernican astronomy and condemn it as impiety. Luther even before the publication of De Revolutionibus had called Copernicus an “upstart astrologer” who foolishly wished to reverse the entire tradition of science while flagrantly contradicting the Holy Bible. Melanchthon and Calvin soon joined in to recommend stringent measures against heresy. Quoting from the Psalms: “the world also is established that it cannot be moved”, Calvin asked “who dare to place the authority of Copernicus above that of the Holy Spirit?” When Rheticus took Copernicus’ paper to Nurnberg to be published, he was forced by the reformers to take it elsewhere. Even in Leipzig where he left the paper with the Protestant Osiander to publish, the latter inserted an anonymous preface without Copernicus knowledge asserting that the heliocentric hypothesis was merely a computational method that should not be taken seriously. This ploy may have saved its publication.
By Galileo’s time in the early 17th c the RC church, with a renewed sense of orthodoxy as a result of the counter-reformation, felt the need to take a definite stand against the Copernican revolution. While in earlier centuries Aquinas or the ancient Church Fathers might have considered the metaphorical interpretation of the Scriptural passages in question (thereby eliminating the apparent contradiction between science and Bible), Luther’s literalism had activated a similar attitude in the RC church. Both the RC church and the Protestants now wished solidity with respect to biblical revelation.
More importantly, Copernicus suffered guilt by association in the case of the mystical, neo-Platonist philosopher and astronomer Giordano Bruno (Italian Dominican, like Aquinas whose was excommunicated from Calvinism in Geneva, and Lutheranism in England: Bruno was b. 1548- d. 1600) who had proposed a heliocentric theory as part of his esoteric philosophy and had been executed by the inquisition for his heretical views. Bruno had claimed that the Bible spoke only to moral issue not issues of nature and this was received with little sympathy by the RC counter-revolution. Bruno had also held heretical views on the trinity and given that he now also held to a heliocentric universe did little to ingratiate him to the pope. Bruno was burned at the stake in 1600 (not for his heliocentric teachings however but for denial of Christ as God and the Holy Spirit as world soul) had made Copernican theory seem very dangerous indeed both to the RC authorities and to the philosopher/astronomers.
Not only did the new heliocentric theory appear to conflict with the Bible but it posed a fundamental threat to the entire Christian framework of cosmology, theology and morality. Ever since the Scholastics, Dante had embraced Greek science and endowed it with religious significance, and the Christian worldview had become inextricably embedded within a Aristotelian-Ptolemaic geocentric universe. Dante’s essential dichotomy between the terrestrial and celestial realms, the great cosmological structure of heaven, hell, and purgatory, the circling planetary spheres with angelic hosts, God’s empyrean throne above it all, the moral drama of human life pivotally centered between the spiritual heavens and the corporeal earth - all this would be called into question with Copernicus. If the earth truly moved then it was not the fixed center of God’s creation and his plan for salvation. The absolute uniqueness and significance of Christ’s intervention into history required, or so it seemed, a corresponding unique significance of the earth. The very meaning of redemption, not just of human history but universal history was at stake. To be a Copernican seemed tantamount to atheism. In the eyes of papal advisors, Galileo’s Dialogues Concerning the Two Chief World Systems, already being applauded throughout Europe, was worse than Calvin and Luther together.
With religion and science in apparent contradiction, and an upstart science at that, a mere new hypothesis, there was little question but that the church would prevail. Awakened to the theological implications of Copernican astronomy and traumatized into doctrinal rigidity by decades of Reformational conflict, the RC church mustered considerable powers of suppression and condemned in no uncertain terms the heliocentric theory. Copernicus’ De Revolutionibus and Galileo’s Dialogue were placed on the Index of Forbidden Books. Galileo (an Italian Benedictine b. 1564 – d. 1642) was interrogated by the inquisition, forced to recant, and placed under house arrest; major RC Copernicans were dismissed from their jobs and banished; all teaching upholding the motion of the earth was prohibited. With Copernican theory the RC tension between reason and faith finally snapped.
Kepler By the time Galileo recanted, the scientific triumph of Copernicanism was already in sight and all attempts by RCs and Protestants to suppress the new theory would soon turn against them. Nevertheless, in the early years of the new theory its success did not seem assured; many ridiculed it in the 16th c. In fact, only a few could understand De Revolutionibus as it was dense (perhaps intentionally so) and mathematically demanding. But neither could they overlook it sophistication and Copernicus was soon known as “the second Ptolemy”. Yet problems remained. For Copernicus was a revolutionary who maintained many of the traditional assumption that in turned out worked against his hypothesis. In particular he continued to believe with Ptolemy that the planets moved in uniform circular motion (which resulted in his system being as complex as Ptolemy’s) and he had to refer to eccentrics and epicycles to make it work, and also to the mathematics of Ptolemy. Moreover he could not counter the simple observation that if the earth did move why didn’t things fall off? Interestingly, Copernicus merely hypothesized a moving earth but he retained the old Aristotelian-Ptolemaic heavens (especially the claim about the uniform circular motion of the planets and so he still required epicycles and hence he required epicycles and eccentrics to make the system work). What appealed to Galileo and Kepler was the aesthetic superiority of Copernicus’ theory (not its scientific accuracy) – his neo-Platonic aesthetic judgment at the root of his claim that the earth moved was responsible for the “scientific revolution” initiating the “new science” – and it was left to Kepler, Galileo, and Newton to formulate a comprehensive theory capable of integrating a planetary earth.
For Kepler, with his passionate belief in the transcendent power of numbers and mathematical form, his vision of the sun as the central image of the godhead, his devotion to celestial “harmony of the spheres” was even more impelled by neo-Platonism than was Copernicus. Writing to Galileo, Kepler invoked Plato and Pythagoras as true preceptors. Kepler believed that Copernicus had intuited something greater than the heliocentric theory was capable of expressing, and that if freed from Ptolemaic assumptions it would open up a new scientific understanding of a harmonious universe that directly reflected God’s glory. In addition, Kepler had inherited a vast book of astronomical observations collected by Tycho de Brahe, Kepler’s predecessors as astronomer of the Holy Roman Empire. [Tycho de Brahe had proposed a system intermediate between Copernicus and Ptolemy in which all the planets except the earth revolve around the sun while the entire sun-centered universe revolves around the earth. Essentially this was modification of the ancient system of Heraclides. Brahe’s system furthered the Copernican cause, especially his observations of comet and of a nova in 1572 which led astronomers to appreciate that the heavens were not immutable, a view subsequently reinforced by Galileo’s telescope. Thus, the comets were now recognized as passing through spaces traditionally thought to be filed by the solid crystalline spheres which Kepler would, in proposal that the planets traveled in ellipses, entire untenable.] Kepler armed with Copernicus’ theory and Brahe’s data set out to formulate the simple mathematical laws that would solve the problem of the planets. For ten years Kepler sought to fit the observations to every possible hypothetical system of circles he could devise focusing particularly on the planet Mars. After this he concluded that it must be some other geometrical figure than the circle that was responsible for planetary orbits. Having mastered the ancient theory of conic sections developed by Euclid and Appolonius, Kepler at last discovered that Brahe’s observations exactly matched orbits shaped as ellipses, with the sun as one of the two foci and with each planet moving at speed varying proportionately to its distance from the sun (fastest nearest to 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 a circular orbit – equal distance on the arc in equal intervals of time. This interpretation ultimately failed despite the ingenuity of astronomers over 2000 years. However, Kepler discovered a new and subtler form of uniformity which 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 formulated 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 cubes of their average distance from the sun.
Thus, Kepler eventually solved he ancient problem of the planets and fulfilled Plato’s extraordinary prediction of single, uniform, mathematically ordered orbits – and in doing so vindicated Copernicus’ hypothesis. With elliptical orbits replacing Ptolemaic circles, and with the law of equal areas replacing that of equal arcs, Kepler was able to dispense with all the complex corrective devices, epicycles, eccentrics, equants, etc. More significantly, one simple geometrical figure and one simply mathematical speed equation produced results that precisely matched the observations – something never before accomplished. [Note here the role of measurement.] What had been a problem of over 2000 years was solved with mathematical elegance and precise empirical standards, and importantly, affirming Copernicus’ theory and the mathematical mysticism (“idealism”, we might say today) of the ancient Pythagoreans and Platonists.
Also important is that Kepler’s laws of planetary motion led directly to a physical account of the heavens (ellipses were continuous straightforward motions of a single shape, whereas the Ptolemaic system of indefinitely compounded circles had no physical reality but was merely an instrumentalist solution, even as Copernicus had argued for its realism). With Kepler’s laws planetary astronomy seemed “real” and so Kepler saved mathematical astronomy by demonstrating that mathematics applied to the reality of the heavens – disclosing actual physical motion (a slowly creeping view of the universe as “mechanism”). Mathematics was not merely an instrument for prediction but an instrument to disclose astronomical reality. Kepler therefore affirmed the Pythagorean claim that mathematics was the key to understanding the cosmos, and directly revealing God’s grandeur of creation.
Galileo With Kepler’s breakthrough, Copernicus’ theory would in time have succeeded in its predictive superiority and scientific realism. But it so happened that in 1609 (the year Kepler published his laws of planetary motion in Prague), Galileo in Padua, Italy directed his telescope which he recently built and made the qualitatively new observations (known since the ancients): craters and mountains on the moon, moving spots on the sun, the four moons of Jupiter, the phases of Venus, the innumerably number of stars in the milky way, all of which he interpreted as evidence in favor of Copernican theory. Obviously these observations (craters on the moon, sunspots) meant that the planets were not perfect (incorruptible and immutable) bodies of Aristotelian-Ptolemaic cosmology. If Jupiter as a moving body could have four suns, then the earth and its moon could also be moving – refuting the ancient argument that the earth could not move around the sun on risk that its moon would along ago have spun off its orbit. If the phases of Venus were visible then Venus must be moving around the sun. If the Milky Way which to the naked eye is a mere nebulous glow proved to consist of millions of stars, then the Copernican suggestion of a much larger universe (to explain the lack of visible annual stellar parallax despite the earth’s movement around the sun) seemed plausible (a universe so large Pascal despaired and spoke of “alienation”). If the planets in the telescope had substantial bodies with extended surfaces and were not just points of light (and yet many more stars were visible without apparent extension) then this also argued for a much larger universe than was envisioned in traditional cosmology. Galileo’s observations were quickly published in his The Messenger of the Stars which created a sensation in European intellectual circles.
Galileo’s observations gave “reality” to the heliocentric theory, and so added to Kepler’s “realism” negating the merely “instrumental” function of mathematics (as a mere computational device enabling prediction). The telescope served to reveal the heavens in their materiality (not merely celestial points of light), concrete substances appropriate for empirical investigation, just like the natural phenomena on earth. The time honored practice of arguing and observing from within the boundaries of Aristotelian thought began to give way to a fresh examination (in the light of Platonic idealism/realism) of empirical phenomena with a critical eye. Many individuals who were not scientific now began to look through the telescope and see a new Copernican universe. Astronomy because of the telescope and Galileo’s convincing writings became a topic for the non-specialist – who found the new astronomy liberating in comparison to the late Renaissance and post Renaissance ecclesiastical doctrine. A new celestial world opened up just as a new terrestrial world was also being discovered (e.g., Columbus). While the impact of Kepler and Galileo was gradual and cumulative, the medieval universe was now dead.
It is possible that the church could have reacted to this new cosmos differently than it did. Seldom in its history had the Christian religion attempted to suppress scientific discovery when it seemingly contradicted Scripture. As Galileo himself pointed out, the church had long been accustomed to sanctioning allegorical interpretations of the Bible whenever it contradicted scientific evidence. Moreover, ecclesiastical authorities did recognize Galileo’s genius including the Jesuit astronomers of the Vatican. In fact, the pope was a friend of Galileo and accepted with enthusiasm the dedication of his book Assayer which outlined the new scientific method. Cardinal Bellarmine, the church’s chief theologian, who finally declared Copernicanism “false”, had earlier written that if there were real proof that the sun was the center of the universe, then we should have to engage in great circumspection in explaining Biblical passages which appear to teach the contrary, or rather to admit that we did not understand these passages rather declare science false.
But a unique and potent set of circumstances dictated that it would be otherwise. The Protestant threat together with the apparently heretical science and with the memory of Bruno still fresh, RC authorities earnestly wished to avoid scandal that might further disrupt reformation-to- Christianity. Making it all the more threatening was the newly invention printing press, and Galileo’s very lucid writings in the vernacular Italian. There were also internal squabbles in the Vatican: Aristotelian professors at universities who wanted to block the anti-Aristotelian Galileo and his all too-popular ideas gave rise to a reaction among fundamentalist preachers who aroused the inquisition. Galileo’s own vitriolic personality which alienated opponents with a vengeance and his insensitivity to the impact of his views on the cosmological revolution taking place, also contributed. Bellarmine’s conviction that mathematics was merely an intellectual construct without any relation to physical reality (he was then a “theory instrumentalist”); Galileo’s espousal of atomism when the RC doctrine of transubstantiation seemed to require Aristotelian physics,; the pope’s sense of personal betrayal exacerbated his political insecurity; the power struggles within the church; the inquisition’s hunger for punitive repression – all these factors coalesced with fateful accord to instill the church’s prohibition of Copernicanism.
The decision caused enormous damage to the church’s intellectual and spiritual integrity. The RC church’s adherence to the geocentric theory undermined its credibility among European intellectuals – and the church could no longer claim to aspire to full knowledge of the universe. After the inquisition banned Galileo’s books/ideas, these books moved north where the vanguard the Western intelligensia would thereafter reside. [Galileo’s last important contribution to physics, New Sciences, 1634, (at age 70) was published in 1638 in Holland. In the same year John Milton traveled from England to Italy where he visited Galileo an event Milton recorded in Areopagitica (1644): a classic argument for freedom of the press against the inquisition/Franciscans and Dominicans.] All this led eventually to an opposition between science and religion (and Galileo was forced to recant to what would be the church’s defeat).
Institutional Christianity as a whole suffered from the Copernican victory which contravened the Protestant’s literal interpretation of the bible, and the RC’s sacramental authority. For the present most European intellectuals remained devoutly Christian, but the schism between science and religion (even in the individual mind/psyche) had announced itself. With Luther, the West’s intellectual independence had asserted itself in religion; with Galileo the West took a step outside religion altogether.