Galileo’s Daughter: A Drama of Science, Faith and Love

‘Now, getting back to my story,’ Castelli went on,

I entered into the chambers of her Highness, and there I found the Grand Duke, Madama Cristina and the Archduchess, Don Antonio [de’ Medici], Don Paolo Giordano [Orsini], and Doctor Boscaglia. Madama began, after some questions about myself, to argue the Holy Scripture against me. Thereupon, after having made suitable disclaimers, I commenced 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 heart that instead of being dismayed by the majesty of their Highnesses I carried things off like a paladin. I quite won over the Grand Duke and his Archduchess, while Don Paolo came to my assistance with a very apt quotation from the Scripture. Only Madama remained against me, but from her manner I judged that she did this only to hear my replies. Professor Boscaglia said never a word.

The troubling news of Madama Cristina’s displeasure inspired an immediate response from Galileo. Even more than he regretted her opposition, he dreaded the drawing of battle lines between science and Scripture. Personally, he saw no conflict between the two. In the long letter he wrote back to Castelli on 21 December 1613, he probed the relationship of discovered truth in Nature to revealed truth in the Bible.

‘As to the first general question of Madama Cristina, it seems to me that it was most prudently propounded to you by her, and conceded and established by you, that Holy Scripture cannot err and the decrees therein contained are absolutely true and inviolable. I should only have added that, though Scripture cannot err, its expounders and interpreters are liable to err in many ways…when they would base themselves always on the literal meaning of the words. For in this wise not only many contradictions would be apparent, but even grave heresies and blasphemies, since then it would be necessary to give God hands and feet and eyes, and human and bodily emotions such as anger, regret, hatred and sometimes forgetfulness of things past, and ignorance of the future.’

These literary devices had been inserted into the Bible for the sake of the masses, Galileo insisted, to aid their understanding of matters pertaining to their salvation. In the same way, biblical language had also simplified certain physical effects in Nature, to conform to common experience. ‘Holy Scripture and Nature’, Galileo declared, ‘are both emanations from the divine word: the former dictated by the Holy Spirit, the latter the observant executrix of God’s commands.’

Thus no truth discovered in Nature could contradict the deep truth of Holy Writ. Even Madama Cristina’s objection regarding the Book of Joshua could be put to rest in terms of the Sun-centred universe; indeed, Copernicus made more sense of the passage than either Aristotle or Ptolemy, as Galileo spent almost half of this letter explaining.

On this day, when the Lord delivered up the Amorrites to the Israelites, Joshua prayed to the Lord, and said in the presence of Israel: Stand still, O sun at Gabhaon, O moon, in the valley of Aialon! And the sun stood still, and the moon stayed, while the nation took vengeance on its foe. Is this not recorded in the Book of Hashar? The sun halted in the middle of the sky; not for a whole day did it resume its swift course. Never before or since was there a day like this, when the Lord obeyed the voice of a man; for the Lord fought for Israel.

JOSH. 10: 12–14

The Ptolemaic system granted the Sun two motions. One of these, a slow annual progression from west to east, belonged strictly to the Sun itself. The other, more apparent, motion of the Sun across the sky over the course of the day – most probably the motion Joshua had sought to halt – actually belonged to the Ptolemaic Primum Mobile, the sphere of the highest sky, which spun all the other spheres containing Sun, Moon, planets and stars around the Earth every twenty-four hours. God’s stopping only the Sun would not have achieved Joshua’s desire. On the contrary, it would have made night arrive about four minutes early.

As Copernicus viewed the sky, however, the passage of day to night resulted from the turning of the Earth. Galileo agreed with Copernicus that the Earth somehow drew this motion from the Sun. Galileo had further observed the Sun to have its own monthly rotation, which he discovered during his studies of sunspots. Just as the light of the Sun illuminated all the planets, so too its motion energised them to pursue their orbits. Therefore, if God had stopped the Sun’s rotation, the Earth would have stopped, too, and the day stretched out to accommodate Joshua’s needs.

Later Galileo would point out that when the Sun stood still in the biblical account, it did so ‘in the middle of the sky’ – precisely where the Copernican system placed it. This reference to location could not be taken to mean the Sun had been standing in the high noontime position, for then Joshua would have found time enough to fight his battle without praying for a miracle to prolong the day.

Despite the strength of his argument, Galileo personally wished to abandon all such astronomical interpretations, on the grounds that the Bible spoke to a more important purpose. As he had once heard the late Vatican librarian Cesare Cardinal Baronio remark, the Bible was a book about how one goes to Heaven – not how Heaven goes.

‘I believe that the intention of Holy Writ was to persuade men of the truths necessary for salvation,’ Galileo continued his letter to Castelli, ‘such as neither science nor any other means could render credible, but only the voice of the Holy Spirit. But I do not think it necessary to believe that the same God who gave us our senses, our speech, our intellect, would have put aside the use of these, to teach us instead such things as with their help we could find out for ourselves, particularly in the case of these sciences of which there is not the smallest mention in the Scriptures; and, above all, in astronomy, of which so little notice is taken that the names of none of the planets are mentioned. Surely if the intention of the sacred scribes had been to teach the people astronomy, they would not have passed over the subject so completely.’

Castelli shared this exquisite exposition with friends and colleagues, who hand-copied it and forwarded it numerous times. Galileo now returned to predicting the positions of the Medicean satellites and to penning responses to various published attacks against his own published works. When his health faltered in March, Castelli, who had been begging Galileo to take better care of himself, stepped in to help him.

In the early days of summer, at the Convent of San Matteo in Arcetri, Virginia and Livia began to wear the dark-brown religious habits of the Franciscan orders. Although both children were still too young to take their vows, mother abbess Suor Ludovica Vinta told the ailing Galileo that she desired to see them appropriately outfitted before she relinquished her elected office.

Young girls received into the monastery before the age required by law shall have their hair cut off round and, their secular dress being laid aside, shall be clothed in religious garb as it shall seem fitting to the Abbess. But when they have reached the age required by law, they shall make their profession clothed after the manner of the others.

THE RULE OF SAINT CLARE, chapter II

Meanwhile Galileo’s letter to Castelli continued to circulate, travelling from hand to hand, and eventually falling into the wrong hands. On 21 December 1614, exactly one year to the day after Galileo wrote the letter, he found himself denounced from the pulpit of the Church of Santa Maria Novella, right in the city of Florence, by Tommaso Caccini, a hotheaded young Dominican priest with ties to the ‘pigeon league’.

Men of Galilee, why do ye stand looking up to heaven?

ACTS I: II

Beginning his sermon with this barb, Caccini moved quickly to the biblical text for that Advent Sunday, which happened to come from the Book of Joshua, and included the ‘Stand still, O sun’ command that had sparked Madama Cristina’s original complaint. Caccini wound up branding Galileo, Galileo’s followers, and all mathematicians in general ‘practitioners of diabolical arts…enemies of true religion’.

The vitriol of the language brought Caccini a reprimand, and Galileo a written apology from the preacher’s Dominican superior. But soon another Florentine Dominican, Niccolò Lorini, submitted a copy of Galileo’s now widely read letter to Castelli to an inquisitor general in Rome. Hearing this news, Galileo feared that crucial passages might have been altered (as indeed proved to be the case) either by mistakes in copying or through malevolent distortion. He sent a true copy to his friend at the Vatican, Piero Dini, who in turn copied it repeatedly for various cardinals who might help clear Galileo’s name.

Through the spring and summer of 1615, Galileo sustained yet another long bout of incapacitating illness – aggravated, perhaps, by his recognition of the forces arrayed against him. Indeed he saw himself the focus of a conspiracy. While bedridden, he recast his informal letter to Castelli into a much longer, more referenced treatise addressed to Madama Cristina herself. (Though no printer dared publish the Letter to the Grand Duchess Cristina until 1636, in Strasbourg, manuscript copies enjoyed a wide Italian readership.)

‘Some years ago,’ he began,

as Your Serene Highness well knows, I discovered in the heavens many things that had not been seen before our own age. The novelty of these things, as well as some consequences which followed from them in contradiction to the physical notions commonly held among academic philosophers, stirred up against me no small number of professors – as if I had placed these things in the sky with my own hands in order to upset Nature and overturn the sciences. They seemed to forget that the increase of known truths stimulates the investigation, establishment and growth of the arts; not their diminution or destruction.

Showing a greater fondness for their own opinions than for truth, they…hurled various charges and published numerous writings filled with vain arguments, and they made the grave mistake of sprinkling these with passages taken from places in the Bible which they had failed to understand properly, and which were ill suited to their purposes.

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 defence 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 practised. 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-centred universe, which dated all the way back to Pythagoras in the sixth century BC, 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 the 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 marvellously 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 splendour 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, labours 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 (#ulink_6e039760-49ad-52f7-8f43-ae379005d72a)

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 honoured 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.

(#litres_trial_promo) 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 after 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 the 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 realise 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 drinking 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 labour 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 pre-eminence and – most important – to protect the honour of the Catholic faith. For if the Holy Fathers banned Copernicus, as rumour 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-centred 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.

(#litres_trial_promo) 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.