by Dava Sobel
Even though Galileo directed these comments to Madama Cristina, he refrained from accusing her of the same injustices, which she had committed without malice. He reserved his venom for those others who used biblical passages they could not comprehend to condemn the worthy theory of Copernicus, which they had not read. He backed his position by quoting Saint Augustine, who advised moderation in piety and caution in judgment on complex issues, so as to avoid condemning hypotheses “that truth hereafter may reveal to be not contrary in any way to the sacred books of either the Old or the New Testament.” In the margins of his fifty-page letter, Galileo footnoted all the theological works he had consulted to construct his thesis concerning the use of biblical quotations in matters of science—allowing the likes of Saint Augustine, Tertullian, Saint Jerome, Saint Thomas Aquinas, Dionysius the Areopagite, and Saint Ambrose to defend him against enemies who sought “to destroy me and everything mine by any means they can think of.”
Galileo felt he understood the motivation of his detractors: “Possibly because they are disturbed by the known truth of other propositions of mine which differ from those commonly held, and therefore mistrusting their defense so long as they confine themselves to the field of philosophy, these men have resolved to fabricate a shield for their fallacies out of the mantle of pretended religion and the authority of the Bible.”
The Holy Fathers of the Church of course occupied a separate category. Yet several of these, Galileo complained, usurped scriptural authority to pronounce judgments in physical disputes, while ignoring any evidence of science to the contrary:
Let us grant then that theology is conversant with the loftiest divine contemplation, and occupies the regal throne among sciences by dignity. But acquiring the highest authority in this way, if she does not descend to the lower and humbler speculations of the subordinate sciences and has no regard for them because they are not concerned with blessedness, then her professors should not arrogate to themselves the authority to decide on controversies in professions which they have neither studied nor practiced. Why, this would be as if an absolute despot, being neither a physician nor an architect but knowing himself free to command, should undertake to administer medicines and erect buildings according to his whim—at grave peril of his poor patients’ lives, and the speedy collapse of his edifices.
Galileo took pains to establish the antiquity of the Sun-centered universe, which dated all the way back to Pythagoras in the sixth century B.C., was later upheld by Plato in his old age, and also adopted by Aristarchus of Samos, as reported by Archimedes in the Sand-reckoner, before being codified by the Catholic canon Copernicus in 1543. Galileo had good reason to suspect that this theory stood on the verge of suppression, and his Letter to Grand Duchess Cristina argued passionately against such action:
To ban Copernicus now that his doctrine is daily reinforced by many new observations and by the learned applying themselves to the reading of his book, after this opinion has been allowed and tolerated for those many years during which it was less followed and less confirmed, would seem in my judgment to be a contravention of truth, and an attempt to hide and suppress her the more as she revealed herself the more clearly and plainly. Not to abolish and censure his whole book, but only to condemn as erroneous this particular proposition, would (if I am not mistaken) be a still greater detriment to the minds of men, since it would afford them occasion to see a proposition proved that it was heresy to believe. And to prohibit the whole science would be but to censure a hundred passages of Holy Scripture which teach us that the glory and greatness of Almighty God are marvelously discerned in all His works and divinely read in the open book of Heaven. For let no one believe that reading the lofty concepts written in that book leads to nothing further than the mere seeing of the splendor of the Sun and the stars and their rising and setting, which is as far as the eyes of brutes and of the vulgar can penetrate. Within its pages are couched mysteries so profound and concepts so sublime that the vigils, labors, and studies of hundreds upon hundreds of the most acute minds have still not pierced them, even after continual investigations for thousands of years.
Having hereby framed his thoughts on paper, Galileo felt the gravity of the situation propelling him to Rome, where he intended to free his reputation of any whisper of heresy, and also to defend the burgeoning study of astronomy with new weapons of his own devising.
Grand Duke Cosimo gave Galileo permission to make the journey— over the objections of his Tuscan ambassador there, who judged Rome a dangerous place for the court philosopher “to argue about the Moon.” Corridors leading to the Vatican and the Holy Office of the Inquisition already hummed with the controversy of his doctrines.
[VII]
The malice
of my
persecutors
Galileo issued his call for a distinction between questions of science and articles of faith at an anxious moment in Church history.
Stunned by the Protestant Reformation fomented in Germany around 1517, the Roman Church struck a defensive posture throughout the sixteenth and seventeenth centuries called the Counter-Reformation. The Church hoped quickly to close the rift that had split Protestantism from Catholicism by convening an ecumenical council, but intrigues and obstacles of all sorts— including disputes over where to stage the event—postponed the meeting for many years, while the rift continued to widen. Finally, Pope Paul III (the same pontiff honored in the dedication of Copernicus’s book) convened bishops, cardinals, and leaders of religious orders at Trent, where Italy bordered the Holy Roman Empire of the German nation. On and off over a period of eighteen years, from 1545 to 1563, the Council of Trent debated and voted and ultimately drafted a series of decrees* These dictated how the clergy were to be educated, for example, and who was empowered to interpret Holy Scripture. Rejecting Martin Luther’s insistence on the right to a personal reading of the Bible, the council declared in 1546 that “no one, relying on his own judgment and distorting the Sacred Scriptures according to his own conceptions, shall dare to interpret them.”
After the council finally concluded the twenty-five sessions of its long-drawn-out deliberations, its decrees became Church doctrine through a series of papal bulls (so named for the bulla, or round lead seal, affixed to pronouncements from the pope himself). In 1564, the year Galileo was born, certain important points from the debates were formulated into a profession of faith, worded by the Council of Trent and solemnly sworn over the ensuing decades by untold numbers of Church officials and other Catholics:
I most firmly accept and embrace the Apostolic and ecclesiastical traditions and the other observances and constitutions of the Church. I also accept Sacred Scripture in the sense in which it has been held, and is held, by Holy Mother Church, to whom it belongs to judge the true sense and interpretation of the Sacred Scripture, nor will I accept or interpret it in any way other than in accordance with the unanimous agreement of the Fathers.
Galileo’s Letter to Grand Duchess Cristina indirectly charged his opponents with violating this oath by bending the Bible to their purposes. His opponents, on the other hand, judged Galileo guilty of the same crime. His only hope of winning the argument lay in producing proof positive for the Copernican system. Then, since no truth found in Nature could contradict the truth of Scripture, everyone would realize that the fathers’ judgment about the placement of the heavenly bodies had been hasty, and required reinterpretation in the light of scientific discovery.
December 1615 thus brought Galileo to Rome brandishing new support for Copernicus—derived from observations of the Earth, not the heavens. The tidal motions of the great oceans, Galileo believed, bore constant witness that the planet really did spin through space. If the Earth stood still, then what could make its waters rush to and fro, rising and falling at regular intervals along the coasts? This view of the tides as the natural consequence of the turning Earth had originally occurred to him nearly twenty years previously, at Venice, when he boarded the barges that carried drin
king water into the city from Lizzafusina. Watching the way the large cargoes of water sloshed in response to any changes in the ships’ speed or direction, he had found a model for the ebb and flow of the Adriatic and the Mediterranean.
Now, lodged at the Tuscan embassy in the Villa Medici, Galileo passed the early part of January 1616 setting down in writing for the first time his theory of the tides. His social life during this labor consisted of meeting with fifteen to twenty men at a time in the homes of various Roman hosts, where he argued Copernicus’s cause in his most compelling style. The nervous Tuscan ambassador, Piero Guicciardini, fairly choked through these evenings, for he dreaded the possible cost of Galileo’s actions.
“He is passionately involved in this fight of his,” Guicciardini complained to the grand duke, “and he does not see or sense what it involves, with the result that he will be tripped up and will get himself into trouble, together with anyone who supports his views. For he is vehement and stubborn and very worked up in this matter and it is impossible, when he is around, to escape from his hands. And this business is not a joke, but may become of great consequence, and the man is here under our protection and responsibility.”
Galileo needed the evidence of the tides to support Copernicus because his astronomical findings to date had failed to prove the Earth’s motion. It was all very well to argue, as Galileo did, that a rotating, revolving Earth made for a more rational universe—that asking the innumerable, enormous stars to fly daily around the Earth at fantastic speeds was like climbing to a cupola to view the countryside and then expecting the landscape to revolve around one’s head. Such reasoning, however, said nothing about the way God had actually constructed the firmament.
Even Galileo’s discovery of the phases of Venus, which he had dealt as a death blow to the Ptolemaic system, did not constitute proof of the Copernican. The planetary system of Danish astronomer Tycho Brahe could take Venus by the horns and still enable the Earth to remain immobile. According to the Tychonic order, the five planets orbited the Sun, while the Sun—surrounded by Mercury, Venus, Mars, Jupiter, and Saturn—circled the stationary Earth. Although Tycho had based this theory on decades of careful observations, Galileo dismissed his plan as even sillier than the Ptolemaic. Since he could not prove the Copernican system by telescope alone, however, he turned to the tides to cement the case. He required the seas to rise to the rescue, not merely of Copernicus’s reputation or his own, but to preserve Italy’s future scientific preeminence and—most important—to protect the honor of the Catholic faith. For if the Holy Fathers banned Copernicus, as rumor predicted they might do at any moment, then the Church would endure ridicule when a new generation of telescopes, probably manned by infidels, eventually uncovered the conclusive evidence for the Sun-centered system.
The waters of the world occupy a moving vessel, Galileo wrote in his “Treatise on the Tides.” This vast container of water turns on its axis once every day and travels around the Sun once a year. The combination of the two Copernican motions accounts for all tides. The timing and magnitude of specific tides in different locations, however, depend also on many contingent factors, including the extent of each body of water (this was why ponds and small lakes lacked tides), its depth (and consequently the volume of fluid involved), the way it orients itself on the globe (since an east-west waterway like the Mediterranean experienced more dramatic tides than the nearly north-south Red Sea), and its nearness to other bodies of water (which proximity could cause powerful currents and floods, as at the Straits of Magellan where the Atlantic met the Pacific Ocean). Galileo, who never once left Italy, had gathered reports from far and wide to flesh out his explication.
“To hold fast the basin of the Mediterranean and to make the water contained within it behave as it does surpasses my imagination,” Galileo declared, “and perhaps that of anyone else who enters more than superficially into these reflections.”
But here, again, the fact that Galileo could not account for the tides without moving the Earth did not prove that the Earth moved. What’s more, his theory of the tides, though carefully crafted and eminently reasonable, was wrong. Throughout his life he ignored the true cause of the tides, which rise and fall by the pull of the Moon, because he failed to see how a body so far away could exert so much power. To him, the concept of “lunar influence” smacked of occultism and astrology. Galileo occupied a universe without gravity* As for the force that made moons orbit planets and planets orbit the Sun in Galileo’s cosmology, they might as well have been pushed around by angels.
Kepler, Galileo’s German contemporary, made the Moon the centerpiece of his own tidal theory. Kepler’s thinking, however, riddled with mystical allusions to the Moon’s affinity for water, alienated Galileo’s strictly logical mind. (Kepler had even posited intelligent beings on the Moon, as builders of the features observed from Earth.) What’s more, Galileo may have had some trepidation about relying on the testimony of a German Protestant.
Galileo presented his manuscript treatise on the tides to one of the newest cardinals in Rome, twenty-two-year-old Alessandro Orsini, a cousin of Grand Duke Cosimo. Galileo wanted Cardinal Orsini to pass the paper on to the current pope, Paul V, whose endorsement might help settle the issue. The young cardinal dutifully delivered the paper, but the sixty-three-year-old pontiff refused to read it. Instead, His Holiness pushed the moment to its crisis by convening expert consultors to decide once and for all whether the Copernican doctrine could be condemned as heretical.
The pope summoned his theological adviser, Roberto Cardinal Bellarmino, the preeminent Jesuit intellectual who had served as inquisitor in the trial of Giordano Bruno. Cardinal Bellarmino, the “hammer of the heretics,” had once confided to Prince Cesi of the Lyncean Academy that he personally considered the opinion of Copernicus heretical, and the motion of the Earth contrary to the Bible. (This admission prompted Cesi to wonder whether De revolutionibus would ever have been published had Copernicus lived after the Council of Trent, instead of before it.)
Bellarmino knew Galileo from meetings at social occasions over a period of some fifteen years, had viewed Jupiter’s moons through his telescope in 1611, and highly respected his achievements, which he could appreciate more than most, having studied astronomy himself at Florence. The only fault Cardinal Bellarmino found with Galileo was the man’s insistence on treating the Copernican model as a real-life scenario instead of a hypothesis. After all, there was no proof. The cardinal further opined that Galileo should stick to astronomy in public and not try to tell anyone how to interpret the Bible.
Roberto Cardinal Bellarmino
The Council of Trent, Cardinal Bellarmino took pains to point out, prohibited the interpretation of Scripture contrary to the common agreement of the Holy Fathers—all of whom, along with many modern commentators, understood the Bible to state clearly that the Sun traveled around the Earth. “The words ‘the Sun also riseth and the Sun goeth down, and hasteth to his place where he arose, etc’ were those of Solomon,” Cardinal Bellarmino wrote,
who not only spoke by divine inspiration but was a man wise above all others and most learned in human sciences and in the knowledge of all created things, and his wisdom was from God. Thus it is not likely that he would affirm something which was contrary to a truth either already demonstrated, or likely to be demonstrated. And if you tell me that Solomon spoke only according to the appearances, and that it seems to us that the Sun goes around when actually it is the Earth which moves, as it seems to one on a ship that the shore moves away from the ship, I shall answer that though it may appear to a voyager as if the shore were receding from the vessel on which he stands rather than the vessel from the shore, yet he knows this to be an illusion and is able to correct it because he sees clearly that it is the ship and not the shore that is in movement. But as to the Sun and the Earth a wise man has no need to correct his judgment, for his experience tells him plainly that the Earth is standing still and that his eyes are not deceived when they rep
ort that the Sun, Moon, and stars are in motion.
Galileo was still in Rome in February 1616 when the inevitable happened. At the request of Pope Paul V, who devoted his papacy to promulgating Council of Trent reforms, the cardinals of the Holy Office framed the Copernican argument as two propositions to be voted on by a panel of eleven theologians:
I. The Sun is the center of the world, and consequently is immobile of local motion.
II. The Earth is not the center of the world, nor is it immobile, but it moves as a whole and also with a diurnal motion.
The unanimous verdict of the panel pronounced the first idea not only “formally heretical,” in that it directly contradicted Holy Scripture, but also “foolish and absurd” in philosophy. The theologians found the second concept equally shoddy philosophically, and “erroneous in faith,” meaning that although it did not gainsay the Bible in so many words, it nevertheless undermined a matter of faith.
The consultors cast their ballots on February 23 and reported their conclusions to the Holy Office of the Inquisition the following day. Although no public announcement came out of official chambers, Galileo got a special summons and personal notification of the outcome almost immediately.
On February 26, two officers of the Inquisition came to collect him from the Tuscan embassy. They escorted him to the palace of Lord Cardinal Bellarmino, who personally met him at the door, holding his cap, as was his polite custom, and bade Galileo follow him to his chair. There he told Galileo about the independent panel’s ruling against the Sun’s placement at the center of the universe. Speaking as the pope’s representative, Bellarmino admonished Galileo to abandon defending this opinion as fact. No record survives of Galileo’s spontaneous reaction to this dashing of all his hopeful efforts, but he doubtless bowed to the cardinal’s command.