The fifth installment of a ten part series which considers the warnings of climate scientists in the context of historical revolutionary scientific theories that met strong resistance from guardians of the status quo…
by: Arthur Hoyle
Part Five — The Copernican Revolution and the Trial of Galileo — Natural Philosophy and Theology Diverge
Copernicus was the definitive Renaissance man whose knowledge and achievements spanned the breadth of European culture in the sixteenth century. Born in Prussia in 1473, he was educated at the University of Kracow, where he studied Aristotelian philosophy in the Department of Arts before moving to Italy, where he took degrees in canon law at Bologna University and medicine at the University of Padua. He was also a classical scholar and humanist who read widely in the Greek philosophers. He spoke six languages—German, Polish, Italian, Latin, Greek, and Hebrew— and wrote in Latin. He held ecclesiastical offices in the Roman Catholic Church, serving as secretary to his uncle Lucas, the Prince-Bishop of Warmia, and Lucas’s successor, Fabian of Lossainen. But astronomy and mathematics were his principal occupation and passion.
In 1503, at the age of thirty, Copernicus, troubled by inconsistencies that he found in the cosmological models of Aristotle and Ptolemy, began work on his heliocentric theory. In his study of the Greek philosophers, he had come across references to the heliocentric system proposed by Aristarchus. When asked by the Bishop of Fossombrone to provide more accurate predictions of the dates of Easter for the Christian calendar, Copernicus used the heliocentric theory to identify the dates of the spring equinox. In 1514 he wrote an outline of the theory, but shared it with only a few close friends. The work that fleshed out the theory, called On the Revolution of the Heavenly Spheres, was completed in 1532 but not published until 1543, the year of his death. Copernicus held back from making the theory public, perhaps fearing the scorn and criticism of the Church. But the Church initially tolerated it because heliocentrism was presented as a theory, not a description of how the planets actually moved. The two most radical propositions of the theory, from the Church’s point of view, were its assertion that the Sun, not the Earth, is the center of the universe, around which the other planets, including the Earth, revolve, and that the Earth rotates daily on its axis, creating the illusion that the Sun is moving across the sky.
Then in 1584 the Italian Dominican friar Giordano Bruno affirmed Copernicus’s heliocentric theory in “The Fifth Dialogue” of a work titled The Ash Wednesday Supper. The Inquisition, which had been established in 1232 by the Holy Roman Emperor Frederick II as a kind of secret state police administered by the Catholic Church, arrested Bruno and tried him for heresy. He was charged with, among other heresies, holding opinions contrary to the Catholic faith, and claiming the existence of a plurality of worlds and their eternity. Bruno also asserted that there was no fixed firmament of stars, and that the heavens were filled with innumerable wandering bodies extending infinitely into space. He even went so far as to speculate that distant planets orbiting a star like the Earth’s Sun might harbor life. Part mystic, part visionary cosmologist, Bruno was in the scientific avant-garde of his time.
Bruno defended his faith and his adherence to Catholic doctrine before the Inquisition, but refused when ordered to recant his cosmological views. He was burned at the stake in 1600, a martyr to science, and his ashes were thrown into the Tiber.
But Bruno’s was not the only voice raised in support of Copernican theory. In 1596 the German astronomer Johannes Kepler published The Cosmographic Mystery, a defense of the heliocentric system. He departed from the Copernican model in arguing that the planets traced elliptical rather than circular orbits around the Sun. Kepler was deeply religious, and he presented the Copernican model as a physical image of God and the Trinity — Father (the Sun), Son (the orbiting planets), Holy Spirit (the space between them). This metaphor may have helped him avoid Bruno’s fate. He also went to great lengths to reconcile the Copernican model with Biblical passages that were being interpreted as geocentric.
The next astronomer to become an advocate for the Copernican theory was the Italian Galileo Galilei. Galileo was a nobleman, well known and well connected in both ecclesiastical and scientific circles. He was a prolific inventor who introduced a number of instruments — the microscope, the thermometer, the micrometer, the chronometer — that advanced scientific study. In 1608 the Dutch scientist Hans Lippersley invented the telescope, and a year later Galileo built his own version of the instrument, greatly improving its optics. Its magnification ratio of 10:1 enabled Galileo to observe the moons orbiting Jupiter and the rings of Saturn. These discoveries he published in 1610 under the title Message from the Stars. He wrote in Italian so that the general public could share in this new knowledge. What he saw through the telescope made him a closet Copernican.
But in 1613 he confided his views to the Benedictine monk Benedetto Castello, and repeated them in another letter sent two years later to the grand duchess dowager Christina. Galileo questioned the authority of Holy Scripture in explaining the cosmos with the remark, “The Bible tells us how to go to heaven, but not how the heavens go.” Copies of the letter circulated, and fell into the hands of a Dominican friar who filed a written complaint of heresy against Galileo with the Inquisition. The Vatican had come to regard the Copernican theory as a threat to papal authority. In 1616 Pope Paul V opined that the Copernican view of the universe was heretical. On the Revolution of the Heavenly Bodies was placed on the Catholic Church’s Index of prohibited books. The Inquisition launched an investigation into Galileo’s views. He was summoned to a meeting with Cardinal Bellarmine, the Inquisitor who had presided over the trial of Giordano Bruno, and ordered to abandon his support of Copernican theory—neither to hold it nor to defend it. Galileo submitted to the order and was exonerated. It was clear that the Church no longer had any tolerance for heliocentrism. When science threatened “business as usual,” science was censored.
Then in 1623 Cardinal Maffeo Barberini, a friend and admirer of Galileo, was installed as Pope Urban VIII. Emboldened by this personal connection, and encouraged by friends, Galileo set to work on a discussion of cosmological design. The work, completed in 1632, was framed as a dialogue between a Copernican named Salviati, a Ptolemaean named Sagredo, and an Aristotelian named Simplicio. Galileo titled the work Dialogue on the Two Greatest Systems of the World, the Ptolemaic and the Copernican.
Galileo brought the manuscript to Rome to share with the Pope. But Urban, distracted by affairs of state, did not have time to read it or to meet with Galileo. The manuscript was reviewed by two sets of censors, both of whom approved it. Subsequently, foes of Galileo at the Vatican persuaded Urban that he was the model for the character named Simplicio. Sales of the Dialogue were banned, and Galileo was summoned back to Rome for interrogation by the Inquisition and placed under arrest. He was charged with violating the order not to discuss Copernican theory, and with presenting the theory as fact, not simply a speculative hypothesis.
Galileo attempted to deny that the Dialogue defended Copernican theory, but the Inquisitors read passages from the book that contradicted this. A member of the Inquisition met privately with Galileo at the apartment where he was being held and urged him to admit that he had made an error. Galileo was then subjected to “rigorous examination,” a euphemism for interrogation under the threat of torture. He faced imprisonment unless he agreed to renounce Copernican theory and forgo any further writing or teaching on the motion of the Earth and the stability of the Sun. Minutes of the interrogation that took place on June 21 indicate that Galileo fully recanted without being tortured. He was found guilty of “vehement suspicion of heresy” and placed under house arrest at his villa outside Florence, but allowed to pursue his other scientific interests. He died in 1642 and was denied burial in hallowed ground. His Dialogue remained on the Index for another two hundred years.
The story of Copernicus and Galileo is another cautionary tale of the struggle between certainty and doubt that science continually prolongs. The Church refused to adapt to the revolutionary upheaval of the geocentric world-view on which its authority and control rested. Scientific truth was forced to give way to established certainties around which the social order of the time was built. Bruno refused to abjure his own vision and paid painfully with his life. Galileo took a more pragmatic path. But scientists persisted in their mission to pursue the truth. Little more than forty years after Galileo’s death, Isaac Newton’s Principia asserted the law of gravitation that explained the planets’ orbits around the Sun.
To Be Continued...
Arthur Hoyle is the author of The Unknown Henry Miller: A Seeker in Big Sur, published in March 2014 by Skyhorse/Arcade. He has also published essays in the Huffington Post and the zine Empty Mirror. His second non-fiction book, Mavericks, Mystics, and Misfits: Americans Against the Grain, will be published later this year through Sunbury Press.