Galileo
Page 12
Galileo then moved on to the particular passage in the book of Joshua where he showed, believe it or not, that a literal interpretation of the text coupled to the Aristotelian-Ptolemaic model would have resulted in shortening the day rather than lengthening it, as Joshua intended! The reason for this unexpected result had to do with the “mechanics” of Aristotle’s vision of the heavens. In Aristotle’s scenario, the Sun participated in two motions: one was its own “private” annual motion from west to east, and the second, a motion of the entire sphere of stars (together with the Sun) from east to west. Stopping the Sun’s “private” motion (from west to east) would have clearly shortened the day, since the Sun would move even faster from east to west. Halting the Sun alone, while allowing the heavenly sphere to revolve, would have literally upset the entire celestial order. In contrast, in the Copernican cosmology, simply barring temporarily the Earth’s spin around its axis would have produced the desired effect.
There is no question that with today’s hindsight, Galileo’s logic seems crystal clear and robustly persuasive. In this sense, he was an even more forward-looking theologian than Cardinal Roberto Bellarmino and other contemporary church officials. Even Pope John Paul II noted that Galileo “proved himself more perspicacious on this issue than his theologian adversaries.” It is important to remember, however, that to a large extent, the objection to Copernicanism had much less to do with the actual cosmological model—the Church was not particularly interested in which planetary orbits astronomers preferred to use—and more with what some Catholics, and church officers in particular, regarded as an unwelcome intrusion of scientists into theology. Consequently, in spite of Galileo’s conviction that he had not only adequately addressed all the issues raised by Christina but also demonstrated that the truth can be hidden behind the appearances, the Letter to Benedetto Castelli and the interpretation of that passage from Joshua were going to come back to haunt him.
If you think that the problem of literal interpretations of old texts of any sort is entirely a thing of the past, think again. In his famous Essays, the French writer Michel de Montaigne recognized already in the sixteenth century that “there is more ado to interpret interpretations than to interpret the things, and more books upon books than upon all other subjects; we do nothing but comment upon one another.” As US Supreme Court decisions have proven time and again, even today, interpretations remain as critically important as they were at Galileo’s time. For Galileo himself, interpretations were about to become almost a matter of life and death.
CHAPTER 6 Into a Minefield
One of the major goals of physics today is to formulate a theory, sometimes dubbed the Theory of Everything, that would elegantly unify all the fundamental forces of nature (gravity, electromagnetism, and the strong and weak nuclear interactions). Such a theory should also self-consistently combine our current best theory of gravity and the universe at large (Einstein’s general relativity) with the theory of the subatomic world (quantum mechanics).
Through his demonstration that celestial bodies and their characteristics are really no different from the Earth and terrestrial attributes, Galileo took the first, insightful step toward such a unification. He showed that the Sun has at its outer layers features (sunspots) that resemble atmospheric phenomena on Earth; that Jupiter (and perhaps Saturn) has even more moons than the Earth; that Venus exhibits phases like the Moon; that the Moon’s surface is covered with mountains and plains like those of the Earth; and that the Earth itself reflects sunlight onto the Moon, just as the Moon brightens the Earth’s nighttime sky. Following these discoveries, one could no longer talk about separate, distinct “earthly” and “heavenly” qualities. Galileo proved that unlike Aristotle’s vision of a sacrosanct, immutable celestial sphere, the heavens are just as prone to change as the Earth—as demonstrated, for instance, by the appearance of novae and comets. About eight decades later, these concepts, together with the mathematization of physics, were precisely the ingredients that opened the door for Newton’s all-embracing theory of universal gravitation.
All of Galileo’s awe-inspiring revelations might have been accepted as constituting incredible scientific progress, were it not for the unfortunate fact that they contradicted the Aristotelian cosmology, which the Catholic Church had adopted as its orthodoxy centuries earlier. What’s more, the Copernican system was bound to be at odds with a worldview that had placed humans at the very center of creation, not only physically but also as a purpose and focus for the universe’s existence. The resistance to the Copernican downgrading of the Earth and its inhabitants would partly explain the later objections to Darwinism—the other theory demoting humans from uniqueness and making them rather a natural product of evolution.
All of this notwithstanding, however, the Church might have still accommodated (albeit with difficulty) a hypothetical system that would have made it easier for mathematicians to calculate orbits, positions, and appearances of planets and stars as long as such a system could be dismissed as not representing a true physical reality. The Copernican system could be accepted as a mere mathematical framework: a model invented so as to “save the appearances” of astronomical observations—that is, to fit the observed motions of the planets.
The crucial act that really brought about the Church’s wrath was what Catholic officials regarded as an unacceptable, impudent invasion into the Church’s exclusive provinces—theology and the interpretation of Scripture. Consequently, even as the opposition to Galileo’s findings on purely astronomical and natural philosophy grounds was starting to abate, the antagonism on account of the theological issues was about to grow.
The stage for the theological debate that was going to play a decisive role in the drama that has become known as the Galileo affair had been set almost a century earlier with the Protestant Reformation. That was the point at which a schism had developed concerning authority in interpretating the Bible. Consequently, the notion that literal readings of Scripture were essential and unassailable was rapidly gaining acceptance among Catholic theologians. The Dominican Scholastic theologian Domingo Bañez, for instance, had expressed his views in 1584: “The Holy Spirit not only inspired all that is contained in the Scripture, He also dictated and suggested every word with which it was written.” Another Dominican theologian, Melchior Cano, went even further when he declared in 1585: “Not only the words but even every comma has been supplied by the Holy Spirit.” And who had the authority to interpret those words? The Catholic Church had already in its arsenal of resources an empyrean answer for that too. The Council of Trent, which had been held between 1545 and 1563 as an embodiment of the fight to counter the Protestant Reformation, issued on April 8, 1546, an unambiguous decree: “In the matters of faith and morals pertaining to the edification of Christian Doctrine, no one, relying on his own judgment and distorting the Sacred Scriptures according to his own conceptions, should dare to interpret them contrary to the sense which Holy Mother Church, to whom it belongs to judge their true sense and meaning, has held and does hold, or even contrary to the unanimous agreement of the Fathers.” Given this authoritarian, uncompromising language, it was becoming clear that Galileo’s rationalizations in his Letter to Benedetto Castelli could attract the censors’ attention.
In some sense, Galileo’s statements about the impropriety of using biblical texts literally in order to contradict observational findings came at the worst possible time, when the Church was extraordinarily sensitive to any attempt to undermine its authority in the interpretation of Scripture. A conflict therefore appeared almost inevitable. Unfortunately, as we shall see in chapter 16, even as late as 1945, Vatican authorities interdicted the publication of a book on Galileo commissioned by the Pontifical Academy of Sciences itself, because they regarded it as too “pro-Galileo” in describing the affair.
In any case, Galileo’s situation in 1615 was going from bad to worse, when the Florentine Dominican Niccolo Lorini sent on February 7 what he called a “true copy” of
the Letter to Benedetto Castelli to Cardinal Paolo Camillo Sfondrati, the prefect of the Sacred Congregation of the Index, to be examined. The Congregation of the Index was the body that was supposed to block the distribution of any printed material deemed contradictory to the Catholic faith. In fact, since the Letter to Benedetto Castelli was not printed, the Congregation of the Index was the wrong address for it. However, since the letter did nevertheless concern matters considered to be related to faith, the prefect forwarded Lorini’s letter together with the Letter to Benedetto Castelli to the secretary of the Holy Office, who immediately asked for the opinion of a consultor. Probably aware that the letter, which Galileo wrote to Castelli rather hastily, could spell trouble, Galileo produced a slightly revised version, in which he more thoughtfully and cautiously presented the theological issues. He then sent the letter with an explanation to his friend the Florentine monsignor Piero Dini. Galileo asked Dini to show the letter to the Collegio Romano mathematician Christoph Grienberger and, if appropriate, also to Cardinal Bellarmino, pointing out that “Nicolaus Copernicus was a man not only Catholic, but religious and a canon, and he was called to Rome under Pope Leo X when, in the Lateran Council, the emendation of the calendar was dealt with, he being utilized as a very great astronomer.”
There has been a fascinating recent story concerning the Letter to Benedetto Castelli. The original version was long thought lost, but in August 2018 it was discovered in the Royal Society’s possession in London, where it apparently has been for at least 250 years, escaping the notice of historians. The rediscovery was made by Salvatore Ricciardo, a postdoctoral science historian at the University of Bergamo, in Italy, who browsed the London Royal Society’s online catalogue for a different purpose. From the differences between the existing versions, we can see Galileo’s attempts to moderate the tone of the original letter. For example, Galileo originally referred to certain propositions in the Bible as “false if one goes by the literal meaning of the words.” He then crossed out the word false and replaced it with “look different from the truth.” He also changed his reference to the Scriptures “concealing” its basic dogmas to the less harsh “veiling.” The reason that the letter had been overlooked by Galileo scholars may have been that when it was catalogued in 1940, it was misdated to 21 December 1618, instead of 1613.
A few of Galileo’s friends recognized relatively early the potential risks that were brewing, and they cautioned him to tread lightly. Federico Cesi, the founder of the Lincean Academy, encountered the theological obstacles right away: when he tried to publish Letters on Sunspots, he failed in several attempts to include in the publication references to biblical texts or to Galileo’s claims that the Bible was in fact more consistent with Copernican views than with Ptolemaic views. For instance, the censors insisted on eliminating the statement in Galileo’s second letter to Markus Welser (which was probably based on the answer Galileo had received from Cardinal Carlo Conti), where he said that the immutability of the heavens was “not only false but erroneous and repugnant to the truths of Sacred Scripture about which there could be no doubt.” Realizing that there was no way to get such comments past the censors, Cesi removed all allusions to the Bible from the publication. Galileo, however, may have not taken sufficient account at that stage of the significance of the censors’ intervention with respect to theology.
Whereas all of Galileo’s well-wishers were advising him to keep a low profile on all theological issues, his opponents were starting to become increasingly vocal. In particular, a fiery, aggressive preacher named Tommaso Caccini became one of a clique that caused the most damage. This particular episode also started with Galileo’s foe Lodovico delle Colombe, who a few years earlier had the dispute with Galileo over the nova of 1604, and who in 1611 wrote the dissertation Against the Motion of the Earth, in which, to Galileo’s dismay, he had drawn Scripture into the conversation. Lodovico, his Dominican brother Raffaello, and a few other Florentine Dominicans (a group known scornfully among Galileo’s friends as the “Colombi,” meaning pigeons) also obtained a copy of the Letter to Benedetto Castelli and attacked Galileo on account of his Copernican views, objecting too, to Galileo’s discussion of spots on the Sun. Unfortunately, the delle Colombe brothers had the ear of Florence’s archbishop and, through him, also of Caccini. The preacher seemed to have turned the act of proving that Galileo and the Copernicans were heretics into his mission in life. Toward this disturbing “goal,” he delivered a fervent sermon on December 21, 1614, from the pulpit at Florence’s Santa Maria Novella, in which, citing again that overused and abused passage from the book of Joshua, Caccini asserted that the Copernican system, with its central, unmoving Sun, “was a heretical proposition.” This incident in itself might have passed relatively unnoticed—Caccini was reprimanded by both his brother, who was the head of the Caccini house, and by other Dominican officials—were it not for the fact that Caccini also went to Rome on March 20, 1615, to testify before the Dominican Michelangelo Seghizzi, the commissary general of the Holy Office. In his deposition, among many other deleterious statements, Caccini said emphatically, “It is a widespread opinion that the above-mentioned Galilei holds these two propositions: the earth moves as a whole as well as with diurnal motion; the sun is motionless.” He added that these propositions were “repugnant to the divine Scripture.”
Even worse, being aware that Paolo Sarpi was on the Inquisition’s watch list because of his role in a dispute between the Venetian Republic and the Pope a decade earlier, Caccini included a malevolent comment emphasizing Sarpi’s friendship with Galileo. Similarly, he deliberately and viciously mentioned that Galileo was corresponding with contemporaries in Germany, knowing that this would raise the specter of Lutheranism and guilt by association in the minds of his listeners.
Around the same time, Castelli, who himself was starting to feel the heat in Pisa, wrote to Galileo to express his concerns, noting in low spirits and frustration, “I am most displeased that the ignorance of some people has peaked so that, condemning science of which they are totally ignorant, they attribute [false] things to science they are incapable of understanding.” Sadly, a similar attitude still characterizes a few of the current climate change deniers.
The disdain for and enmity toward science we are experiencing today is precisely the type of attitude Galileo was fighting against. Through his attempts to separate science from the interpretation of Scripture and his reading of the laws of nature from experimental results rather than associating them with a certain “purpose,” Galileo was one of the first to implicitly introduce the idea that science compels us to take responsibility for our own destiny, as well as our planet’s.
Castelli, after acknowledging the gloomy reality that he and Galileo were about to face, added in his letter: “But patience, for these impertinences are neither the first nor the last.” In a letter dated January 12, Cesi expressed precisely the same sentiments, referring to the attackers on Copernicanism as “the enemies of knowledge.” Cesi also took the opportunity to reiterate his advice to Galileo to remain inconspicuous. His strategy for dealing with the onslaught was to recruit other mathematicians and to present the entire affair as an assault on mathematicians, rather than to try to advocate the truth inherent in Copernicanism.
In the meantime, the Letter to Benedetto Castelli was continuing to cause problems. The consultor that the Holy Office employed came back with relatively minor reservations, and even those addressed only three of the statements made in the letter, adding that “for the rest, though it sometimes uses improper words, it does not diverge from the pathways of Catholic expression.” Unfortunately, this benign judgment only incentivized the Holy Office to dig deeper. To that effect, it asked the inquisitor of Pisa to obtain the original letter from Castelli himself.
While all of this turmoil was happening, Monsignor Dini was busy trying to help Galileo in any way he could. He gave copies of the slightly revised Letter to Benedetto Castelli to both Grienberger and Cardinal Bellarmino,
and he consulted about the entire situation with the young church official and poet Giovanni Ciampoli, who knew Galileo and had been a childhood friend of Cosimo II de’ Medici’s. Ciampoli had been freshly ordained as a priest in Rome in 1614. In response to Dini’s appeal, he transmitted directly to Galileo advice from Cardinal Maffeo Barberini (later to become Pope Urban VIII), saying that “he [Barberini] would like greater caution in not going beyond the arguments used by Ptolemy and Copernicus, and finally in not exceeding the bounds of physics and mathematics. For to explain the Scripture is claimed by theologians as their field, and if new things are brought in even though to be admired for their ingenuity, not everyone has the dispassionate faculty of taking them just as they are said.” In other words, Cardinal Barberini’s unequivocal recommendation was that Galileo should stay away from any new interpretations of the Bible.
Similar directives were coming from Cardinal Bellarmino, too, also via Dini. The cardinal’s assessment was that Copernicus’s book On the Revolutions of the Heavenly Spheres would not be prohibited, but that a note would be added, to present the Copernican system as merely a mathematical model. Bellarmino suggested further that Galileo should adopt the same stance, since, he noted, the biblical text in Psalms 19:5–6 stood, in his view, in clear contradiction to the notion of a Sun standing still: “In the heavens, he has pitched a tent for the sun, which is like a bridegroom coming forth from his pavilion, like a champion rejoicing to run his course. It rises at one end of the heavens and makes its circuit to the other, nothing is hidden from its heat.” Dini himself protested that this text could be interpreted as a poetic way of speaking, but Bellarmino retorted that this was “not something to jump into, just as one ought not to jump hurriedly into condemning any one of these opinions.”
Unconvinced, Galileo sent a long answer to Dini on March 23, 1615, in which he tried to address Bellarmino’s comments. He started by pointing out that in the biblical description in Genesis, light was created before the Sun. He then suggested that this light “unites and fortifies itself in the solar body,” which needs to be at the center of the universe, because it “diffuses this light and prolific heat that gives life to all the members that lie around it.” With regard to the passage from Psalms, Galileo argued that the implied motion was of the radiation and caloric spirit, “which, leaving from the solar body, is swiftly diffused throughout the entire world,” and not of the Sun itself. Finally, since he had no theory of gravitation, Galileo used his discovery of the Sun’s rotation about its axis to suggest a rather far-fetched model (knowing what we know today), in which this rotation was somehow driving the revolutions of the planets around the Sun. Since by writing this letter Galileo basically ignored all the cautionary advice given to him, Dini wisely decided (after consulting with Cesi) not to give this response to Cardinal Bellarmino.