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Roman Clouds: on Galileo's third trip to Rome (10 December 1615 - June 1616)

by William R. SHEA

Galileo was paid on the budget of the University of Pisa, but he had no intention of lecturing and considered himself a research professor. He engineered an appointment for his favourite student, a Benedictine priest, Benedetto Castelli, and had him teach the usual undergraduate courses. When Castelli arrived in Pisa in the autumn of 1613, the Overseer of the University told him that he was under no circumstances to discuss the motion of the Earth in his lectures. Castelli replied that he had no such intention, wisely adding that his own teacher in Padua, Galileo, had never done so. Shortly thereafter, the Tuscan court arrived in Pisa for their annual visit, and Cosimo II invited Castelli to his table. When he arrived on Thursday, 12 December 1613, Castelli found the Granduke's mother, Christina of Lorraine, the Granduke's wife, Maria Maddalena, and several other guests including Prof. Cosimo Boscaglia, a colleague from the University of Pisa. Here is Castelli's account of the conversation as he communicated it to Galileo a couple of days later:

Thursday morning I was at table with our Patrons and when asked by the Granduke about the University, I gave him a detailed account of every­ thing, with which he showed himself much pleased. He asked me if I had a telescope. I said yes, and I began to tell about an observation of the Medicean planets I had made the night before. Madama Christina want­ ed to know their position, whereupon the talk turned to the reasons for their being real objects and not illusions produced by the telescope.

Professor Boscaglia agreed that they were indeed real, and Castelli proceeded to tell them about Galileo's determination of the or­ bits of the satellites of Jupiter. The meal ended pleasantly, and Castelli took his leave, but "hardly had I come out of the palace," the letter continues,

when I was overtaken by the porter of Madama Christina, who called me back. But before I tell you what followed, you must first know that while we were at table Doctor Boscaglia had had Madama's ear for a while, and while conceding as real all the things you have dis­ covered in the sky, he added that the motion of the Earth was some­ how incredible, and could not take place ma inly because it went aga inst Holy Scripture.

Madama Christina was a devout Catholic who listened to her confessor and was devoted to the Pope even when His Holiness' interests might be at variance with those of the Tuscan govern­ ment. She also knew her Bible and could refer to the Book of Jo­ suah where the Sun, not the Earth, is ordered to stop in its tracks. Upon re-entering the Palace, Castelli found that some of the guests were still there including Professor Boscaglia, Paolo Gior­ dano Orsini, a cousin of the Grand Duke, and Antonio de Medici, an adopted son of the Duke's grandfather, Cosimo I. "The Grand Duchess", Castelli went on,

began to argue Holy Scripture against me. Thereupon, having made suitable disclaimers, I began to play the theologian with such assurance and dignity that it would have done you good to hear me. Don Antonio assisted me, giving me such h eart that instead of being dis­ mayed by the majesty of Their Highnesses I carried things off like a paladin. I quite won over the Granduke and his Archduchess, while Don Paolo came to my assistance with a very apt quotation from Scripture. Only Madama Christina remained against me, but from her manner I judged that she did this only to hear my replies. Professor Boscaglia never said a word.[1]

Although he was not displeased with Castelli's answers, Galileo's mind was not completely at rest, and he saw that he must intervene. Within a week he put down his own ideas on paper in the form of an Open Letter to Castelli, which could be shown to friends. This was to be his first but not his last incursion into the­ ology. Personally, he saw no conflict between science and religion, and he was anxious that no line of battle should be drawn between the two. He readily admitted that Scripture cannot err, but this did not imply that its interpreters were always right. This was particularly the case when they insisted on the literal meaning. For in this way, we would have to say that God has hands and feet and eyes, and human emotions such as anger, regret, hatred, and sometimes forgetfulness of the past and ignorance of the future.

Galileo argued that this way of speaking had been introduced into the Bible for the sake of the masses, and only to help them in matters concerning salvation. "Sacred Scripture and nature", he declared, "both proceed alike from the Divine Word, the former as a dictate of the Holy Spirit and the latter as the obedient executrix of God's commands". [2] No truth discovered in nature can contradict the Bible. Indeed Copernican astronomy even makes the miracle of Josuah arresting the Sun easier to understand, ac­ cording to Galileo, because if the Sun was seen to stop, this indicated that the Earth no longer revolved and, therefore, that the day had been automatically prolonged. This explanation of the miracle of Josuah, however ingenious, was highly speculative, and it cast Galileo in the dangerous role of telling theologians how to interpret Scripture.

Galileo expanded his letter to Castelli into a small treatise that he addressed to the Granduchess, and which became known as the Letter to Christina of Lorraine. It was only published in 1635 in Strasbourg, along with a Latin translation by a Protestant scholar, but copies of the original version had been widely circulated in Italy prior to that date. One was sent to the Inquisition in Rome, and an enquiry was opened, but the issue was left pending. Nonetheless, rumours began to fly, and Galileo thought that it would be wise to go personally to Rome to silence his critics. He now believed that he had a valid physical proof for the motion of the Earth, an argument from the tides to which we shall come in a moment. Meanwhile someone else threw his hat in the ring. Paolo Antonio Foscarini, an otherwise unknown friar from southern Italy, wrote an essay on the compatibility of Copernicanism with Scripture and sent a complimentary copy to the Head of the Inquisition, Cardinal Roberto Bellarmine. The remarkable thing is that the Cardinal took time off from a very busy schedule to write, in his own hand, a thoughtful and considerate reply on 12 April 1615.

Assuming, like most of his contemporaries, that Copernicus had put forward his system merely as a calculating device to determine the position of the planets, Bellarmine began by com­ mending the prudence that Foscarini and Galileo had displayed "in speaking only hypotheticall y, as I have always believed Copernicus did". For good measure the Cardinal added that the Council of Trent ruled out interpretations of Scripture that were contrary to the consensus of the Church Fathers, all of whom took the passages about the Sun's motion literally. Because of its great importance in the subsequent debate, Cardinal Bellarmine's letter deserves to be quoted extensively: 

The words, the Sun also rises and the Sun goes down and hasten to its place where he arose, etc, were those of Salomon, who not only spoke by divine inspiration but was a man wise above all others and most learned in the hum an sciences and in the knowledge of all created things. His wisdom was from God, and it is not likely that he would affirm something that went against a truth that was already demonstrated, or likely to be. Now if you tell me that Solomon spoke only according to appearances, and that it seems to us that the Sun goes around when actually it is the Earth that 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 moving. 

But as to the Sun and the Earth, a wise man has no need to correct his judgement, for his experience tells him plainly that the Earth is standing still and that his eyes are not deceived when they report that t he Sun, the Moon and the stars are in motion.[3]

Bellarmine did not consider whether biblical statements about the motion of the Sun were just an unexamined assumption, but immediately expressed his own theological conviction that there can be no errors in Holy Writ. For him it was no answer to say that the motion of the Earth is not a matter of faith because what is at stake is nor the subject matter but the veracity of its source, namely the Holy Spirit. On Bellarmine's view, it is just as heretical to deny that Abraham had two sons and Jacob twelve as to deny that Christ was born of a virgin. Furthermore, Bellarmine stressed the logical point that although Copernicanism might work as an astronomical system, this did not imply that it was physically true. In case of doubt it would not be reasonable to ask the Church to dismiss the common interpretation of Scripture. If there was a proof of the motion of the Earth, then the Cardinal agreed that we would have to carefully examine the scriptural passages that seem contrary and confess that we do not under­ stand them rather than say that something that has been proved is false. But he had, as yet, seen no such proof.

Lest we misunderstand the historical situation, we must bear in mind that Galileo, whom we celebrate as the Father of the scientific revolution, had already entered his fifty-third year without having published the great Copernican book that he had advertised as forthcoming in 1610. His reputation rested on his telescopic discoveries, admittedly brilliant but due in large part to the availability of good lenses in the Venetian Republic. He had seen new things sooner and better than others, but this was due to an optical tube rather than any mastery of optics, about which he knew little. He was undoubtedly a versatile writer and an entertaining speaker, but professionals considered him a gifted amateur when it came to philosophy. There was no indication that he was a particularly good teacher, and he never lectured at the University of Pisa, where his colleagues complained that he was overpaid. Furthermore, he had no training whatsoever in theology. He bad been asked, very politely, to prove that the Earth really moved before demanding that the Church reinterpret the Scriptures. Instead of making a gesture to comply, he had become increasingly annoyed at what seemed to him the pig­ headedness of the academic world. Galileo was getting restive and felt that he could carry the day if he were allowed to use his tongue instead of his pen. This is why he had to go to Rome. He felt this was the only honourable course, and he believed that it was also in the best interest of the Church. Bellarmine and Maffeo Barberini declared that Copernicus had proposed his theory as pure speculation. But they were wrong, as Galileo was anxious to let them know.

Galileo arrived in Rome on 10 December 1615, an immediately took up the cudgels as we know from a letter of Monsignor Querengo to Cardinal d'Este:

You would be delighted to hear Galileo argue, as he often does, in the midst of some fifteen or twenty persons who attack him vigorously, now i n one house, now in another. But he is so well buttressed that he laughs them off; and although the novelty of his opinion leaves people unpersuaded, yet he shows that most of the arguments, with which his opponents try to overthrow him, are spurious. Monday in particular, in the house of Federico Ghislieri, he performed marvellous feats. What I liked most was that, before an swering objections, he improved on them and added even better ones, so that, when he demolished them, his opponents looked all the more ridiculous. [4]

Galileo's eloquence and his brilliant repartees made for great sport in the literary circles to which he was repeatedly invited, but the applause that he won bad little to do with a genuine under­ standing of the nature of the argument. Most people enjoyed the liveliness of the discussion but treated the whole matter as a suit­ able topic for a debating society rather than a serious scientific enquiry.

The melancholy outcome of Galileo's campaign in favour of Copernicanism was that the Holy Off ice took an interest. On Thursday, 19 February, the Holy Office decided to submit to a panel of eleven experts the following propositions: "The Sun is at the centre of the world and hence immovable of local motion. The Earth is not the centre of the world, nor immovable, but moves according to the whole of itself, also with a diurnal motion." The consultants met on Wednesday, 24 February, and made the following recommendations: (1) the notion that the Sun is at the centre of the world and at rest is "foolish and absurd in philosophy, and formally heretical, inasmuch as it expressly con­ tradicts the doctrine of the Holy Scripture in many passages, both in their literal meaning and according to the general interpretation of the Fathers and Doctors"; (2) the statement that that the Earth moves, "deserves the same censure in philosophy and, as regards theological truth, is at least erroneous in faith." [5] The experts could only advise; all decisions rested with the Pope and the cardinal inquisitors. The very next day, on Thursday, 25 February 1616 the following course of action was decided upon: Bellarmine was to summon Galileo and enjoin him to abandon Copernicanism. According to an unsigned memorandum, Galileo was called in by Cardinal Bellarmine in the presence of the Commissioner of the Holy Office and two guests, and informed, on behalf of His Holiness the Pope and the Congregation of the Holy Office, to relinquish altogether the theory that the Sun is at the centre of the world and at rest and that the Earth moves; nor henceforth to hold, teach, or defend it in any way verbally or in writing. Otherwise proceedings would be taken against him by the Holy Office. Galileo acquiesced and promised to obey.

This minute was probably penned by some zealous official (who speaks in the first person) who wanted to record that the Commissioner had actually stepped in to give Galileo a strict injunction to relinquish Copernicanism altogether.

We now move from the Holy Office to the Congregation of the Index, where five Cardinals, including Maffeo Barberini, met in Bellarmine's office on Tuesday, 1 March 1616. After discussion, they recommended: that the works they had been asked to judge be censured, but not exactly in the terms that had been proposed by the experts. At Cardinal's Barberini's request, the motion of the Earth was not described as "heretical", but Copernicus' De Revolutionibus was taken out of circulation until corrections were made. Galileo was not mentioned.

Transparency is a great virtue. Things that are done in the open are less likely to be distorted or used in ways that were not in­ tended. But privacy is also an important aspect of social life, and the most liberal citizen will value confidentiality when his purse or his life is at stake. Galileo had not been asked to defend him­ self before the Tribunal of the Inquisition, and the admonition that he received from Cardinal Bellarmine was given in private, and he could rely on the discretion of those who had communi­ cated it. If the did not tell anyone, it would never be bruited. Galileo chose, wisely, to keep mum. On 6 March, he wrote to Curzio Picchena, the Tuscan Secretary of state, to say that he had not written the week before because nothing had happened. But one of the most important events in his life had taken place: he had been admonished by Cardinal Bellarmine to abandon Copernicanism! But this was a personal matter and Galileo prayed to heaven that it would stay so. Yet Romans could put two and two together: Galileo had been campaigning vigorously for Copernicanism, which had now been officially decried as false and contrary to Scripture. Even Monsignor Querengo joked about it in a letter to Cardinal d'Este:

Galileo's arguments have vanished into alchemical smoke, for the Holy Office has declared that to maintain this opinion is to dissent manifestly from the infallible dogmas of the Church. We now know that, instead of imagining that we are spinning in outer space, we are at rest at our proper pace, and do not have to fly off with the Earth like so many ants crawling around a balloon.[6]

The puff of smoke, the ants, and the balloon are quite ingenious, but Querengo knew better than to speak of the immobility of the Earth as an infallible dogma. The decree that proscribed Copernicus and other works that taught heliocentrism did not involve the infallibility of the Church, the pope or anyone else. It was, in the eyes of those who prepared and approved it, a prudential decision to remove from public circulation works that might lead unwary readers to misunderstand the nature of science and the role of Scripture. The Counter Reformation did not encourage discussion or debates about doctrinal matters. The theological pendulum that the reformers had pushed too far in one direction was now made to swing to the other extreme, but even the most conservative cardinals would not have considered a decree of the Congregation of the Index as offering a definitive statement of the Catholic faith.

Before leaving Rome, Galileo was granted and audience by Pope Paul Von 11 March. The next day he proudly reported that he had been allowed to accompany the Pope for a stroll in the gardens for three-quarters of an hour, and that the Pope had assured him that he "could feel safe" as long as he was alive. [7] Meanwhile rumours were flying all over Italy that he had been summoned to Rome and charged with heresy. On 20 April, Castelli wrote from Pisa to report that it was said that he had secretly abjured his errors before Cardinal Bellarmine. Three days later, his friend Giovanfrancesco Sagredo confirmed that the same gossip had rumbled through Venice.

Only one course was open to Galileo. He had to appeal to Cardinal Bellarmine himself. He was given a friendly reception, and the cardinal even provided him with a certificate that exonerated him completely. The document began,

We, Robert Cardinal Bell arm ine, having heard that it is calumniously reported that Signor Galileo Galilei has in our hand abjured and has also been punished with salutary penance, and being requested to state the truth as to this, declare that the said Galileo has not abjured, either in our hand, or the hand of any other person here in Rome, or anywhere else so far as we know, any opinion or doctrine held by him. Neither has any salutary penance been imposed on him; but that only the declaration made by the Hol y Father and published by the Sacred Congregation of the index was notified to him, which says that the doctrine attributed to Copernicus that the Earth moves around the Sun and that the Sun is stationary at the centre of the world and does not move from east to west, is contrary to the Holy Scriptures, and therefore cannot be defended or held. In witness whereof we have written and subscribed the present document with our own hand this twenty-sixth day of May 1616. [8]

With this certificate in his pocket, Galileo felt that he could con­ tinue to publicly consider heliocentrism as a convenient, albeit ar­ bitrary, mathematical tool and, in the secret of his heart, hope that the decree might one day be revoked.

[1] Letter to Galileo, 14 December 1613, in Galileo Galilei, Opere (edited by A. Favaro). Florence: G. Barbera, 1890-1909, pp.605-605
[2] Letter to Christina of Lorraine, Opere, vol. 5, pp.316
[3] Letter to Foscarini, 12 April 1615, Opere, vol. 12, pp. 171-172
[4] Antonio Querengo to Alessandro D'Este, 20 January 1616, Opere, vol. 12, pp. 226.227
[5] Censure of the Holy Office, 19 and 25 February 1616, Opere, vol. 19, p. 348
[6] Antonio Querengo to Alessandro D'Este, 5 march 1616, Opere, vol. 12, p. 243
[7] Letter to Curzio Picchena, 12 March 1616, Opere, vol. 12, pp. 248
[8] Certificate by Robert Bellarmine, 26 May 1616, Opere, vol. 19, pp. 348. 

W. R. SHEA, Galileo's Roman Agenda (Uppsala: Uppsala University Office for History of Science, 2004), pp. 11-21