The Theory of Heliocentrism

Eyeglasses are one of the many inventions that we take for granted today, but that have quietly changed the lives of uncountable millions of people for the better. The ancient record is filled with anecdotes of scholars who literally went half-blind poring over texts in shaky candlelight, and were thereafter cut off from the cultural conversation as irrevocably as if it had been their hearts rather than their eyes that failed them. Meanwhile millions of children who were born near-sighted were doomed to spend their lives as semi-invalids, as handicapped in what they could do and achieve as if they had been born with a defect of the brain or the limbs. As the psychologist Nicholas Humphrey once said, eyeglasses “have effectively doubled the active life of everyone who reads or does fine work, and prevented the world from being ruled by people under 40.” Among the people whose career eyeglasses alone made possible was Johannes Kepler, who wore them from an early age.

We will never know for certain who was the first person to discover that placing convex lenses over the eyes makes them better at seeing objects up-close, while concave lenses make them better at seeing objects that are far away. We don’t even know if it was the same person who discovered both of these things. What we can say is that eyeglasses seem to have emerged in Europe fairly soon after glass-making techniques there had advanced far enough to make them practically feasible. Our first firm evidence for the existence of spectacles is a sermon preached by a priest in Pisa in 1306: “It is not twenty years since that there was found the art of making eyeglasses, which make for good vision, one of the best arts and most necessary that the world has.” That said, it’s possible, even likely, that the invention did not spread across Europe from a single source but was arrived at independently in a number of different places. Regardless of where and how they emerged, eyeglasses were one of the early indelible signs that Europe was marching forward again when it came to technology, that it was becoming capable of technological feats that thoroughly superseded the capabilities of the hallowed ancients.

Ironically, a rudimentary telescope does not not require any more sophisticated glass-making techniques than does an ordinary pair of eyeglasses. And yet it took an additional 300 years for the telescope to emerge. This is odd on the face of it; the most interesting question surrounding the history of the telescope is simply why it took so long to make the scene. As we have seen, Kepler published an entire treatise on optics in 1604 — but he failed to make the seemingly obvious leap to applying it directly to astronomical observation. Before him, Tycho Brahe was an immensely talented inventor of instruments — but he too failed to invent an instrument for magnifying the heavens. Even Galileo Galilei, the man who would make the telescope synonymous with astronomy throughout Europe, never thought to invent it himself. Its potential as a tool for stargazing struck him only after he saw a finished model, in the form of a “spyglass” intended for terrestrial surveying.

Galileo didn’t know whom he had to thank for the spyglass. “We are certain,” he wrote in 1623, well after the events in question, “that the first inventor of the telescope was a simple spectacle-maker who, handling by chance different forms of glasses, looked, also by chance, through two of them, one convex and the other concave, held at different distances from the eye, saw and noted the unexpected result, and thus found the instrument.” It is easy enough to believe that this must have happened many times in spectacle-makers’ workshops between 1300 and 1600, but it took that span of 300 years for anyone to grasp the immense usefulness of the phenomenon and make an effort to advertise it to the broader world.

As best we can determine, that someone was Hans Lipperhey, a German spectacle-maker who was living in Middelburg, a town in what is today the Netherlands, at the same time that Kepler was Imperial Mathematician in Prague and Galileo was a professor in Padua. The story goes that a couple of children who were playing in Lipperhey’s shop happened to hold the two different types of lenses in a line with one another — a convex lens farther from their eyes, a concave one closer — and look through them toward the weather vane at the top of the town church. They called Lipperhey over to show him how the weather vane was magnified, how it could be seen through the two lenses as clearly as if the observer had been perched on the roof of the building right next to it. In the past, all of the energy of people like Lipperhey had been directed toward the restoration of eyesight, toward making those with flawed vision able to see as well as everyone else. But this was something else entirely: the improvement of vision, so that a person with the right optical equipment could see things at a distance that even the most keen-eyed lookout without such equipment could not.

Sensing that he was onto something big, Lipperhey worked to package his discovery into a proper optical instrument. He took a tapered hollow tube made out of tin, about one foot (.3 meters) long and roughly the diameter of a human eye at one end, three or four times larger at the other. He fitted a concave lens at the smaller end, a convex lens at the larger one. When he tested it out, he found that the gadget functioned as he had hoped it would, making distant things appear close-up when one peered into the smaller end of the tube with one eye. The application for his invention that he thought of first was not astronomy but warfare. He called it a spyglass, because of the way it would let the army that possessed it “spy” on the enemy’s position without having to send a reconnaissance team into danger. (One might go so far as to call it the distant forefather of the spy satellites of today.)

In September of 1608, Lipperhey brought his spyglass to The Hague, the capital of the recently established Dutch Republic. There he presented it to Maurice, Prince of Orange, who was the First Steward (Stadtholder) of the republic. Impressed, Maurice then showed it to a gaggle of other luminaries, including his younger brother and eventual successor Frederick Henry and Ambrogio Spinola, a general from Spain, the kingdom from which the Dutch Republic had just won its independence. A court chronicler captured the occasion.

A spectacle-maker from Middelburg, a humble, very religious, and God-fearing man, presented to His Excellency certain glasses by means of which one can detect and see distinctly things three or four miles [5 to 6.5 kilometers] removed from us, as if we were seeing them from 100 paces. From the tower of The Hague, one clearly sees, with the said glasses, the clock of Delft and the windows of the church of Leiden, despite the fact that these cities are distant from The Hague one-and-a-half and three-and-a-half hours by road, respectively. When the States [the representatives in the legislature] heard about them, they asked His Excellency to see them, and he sent them to them, saying that with these glasses they would see the tricks of the enemy. Spinola too saw them with great amazement, and said to Prince Henry, “From now on, I could no longer be safe, for you will see me from afar.” To which the said prince replied, “We shall forbid our men to shoot you.” The master maker of the said glasses was given 300 guilders and was promised more for making others, with the command not to teach the said art to anyone. This he promised willingly, not wishing that the enemies would be able to avail themselves of them against us.

By way of an afterthought, our chronicler noted in passing that “even the stars which ordinarily are invisible to our sight and our eyes, because of their smallness and the weakness of our sight, can be seen by means of this instrument.” It was the first hint of a realization that the spyglass could become the telescope, the most revolutionary invention in the history of astronomy.

The Dutch government’s efforts to keep the new optical technology a secret were hopeless from the start. Too many people had heard about it — not least Spinola, arguably the greatest military leader of the age. The core workings of the gadget were too simple for others not to duplicate Lipperhey’s design in short order, even without that good burgher’s assistance. Lipperhey himself never got to see the full impact of his invention. He died just one year after his big day at The Hague.

Over that year, the spyglass spread across Europe like wildfire. Virtually every monarch on the continent was given demonstrations and sample instruments to play with; ditto Pope Paul V in Rome. Naturally, these instruments varied wildly in quality. Some could only magnify by a factor of three, and that blurry and headache-inducing; some magnified by a factor of eight or even ten with perfect clarity. Their obvious military applications notwithstanding, most people treated spyglasses more as curiosities than useful tools. Barkers stood at street corners in many a European city, charging passersby a copper or two to peer through one of the strange tubes that made faraway things appear to be nearby.

In or around April of 1609, Galileo bought or was loaned a spyglass that had made its way to the precincts of Venice from France. It was one of the poorer examples of the breed. But luckily, he was a seasoned instrument-maker who lived close to some of the best glass-makers in all of Europe. Galileo soon made a spyglass that could magnify distant objects by a factor of no less than twenty. When he started to show it around Padua and Venice, it won him a notoriety unlike anything he had yet experienced.

Being a man of commerce as well as learning, Galileo appears to have seen the spyglass first as a business opportunity. That summer, he arranged a demonstration at the top of the bell tower of Saint Mark’s Cathedral in Venice. Everyone who was anyone in the city-state, from Doge Leonardo Donato on down, turned out to clamber up the narrow stairs and take their turn peering through the magical tube; some reluctantly returned to ground level only to get back in line and walk up again. “Keeping one eye open and the other shut,” wrote one of the punters, “each of us clearly saw beyond Liza Fusina and Marhera, also Chioggia, Treviso, and even Conegliano, and the bell tower and domes with the façade of the church of Santa Giustina in Padua. We could make out those entering and leaving the Church of San Giacomo in Murano. We could see people getting in and out of the gondolas by the column of the ferry crossing at the beginning of Rio de’ Verieri, with many other details of the lagoon and the city that were truly admirable.”

Although Galileo hadn’t been the first to make a spyglass, everyone could agree from this day on that he made the best ones. But he refused to rest on his laurels. Through relentless experimentation, he learned that “it is best if the cannon can be lengthened and shortened a bit, by about three or four digits, because I find that to see nearby objects the cannon must be longer, and shorter for things farther away.” He learned as well that “it is best that the convex lens, which is the one further from the eye, be partly covered and that the opening that is left be oval in shape, since in this way objects are seen much more distinctly.” In Galileo’s hands, the spyglass was becoming a true precision instrument. He couldn’t fully explain why it worked, but he was enough of an empiricist that he didn’t need to understand the science behind it to make it better. The government of Venice offered him a salary of 1000 ducats per year to make spyglasses exclusively for the Venetian military, keeping them out of the shops and not divulging the secrets of their construction to anyone. Galileo happily agreed, for this was a lot of money indeed, more than he had ever had at his disposal before.

Having thus feathered his nest, Galileo finally turned the spyglass to the purpose which must surely have occurred to him as soon as he had seen his first one: he began to point it at the heavens. There were some small early difficulties in turning the spyglass into a telescope: he had to build a stand to hold it steady and stable over long sessions of stargazing, had to fit masking material around the lenses to tamp down the bright halos that surrounded the luminous bodies in the sky. But right from the first, he was seeing wonders the likes of which no one had ever seen before, wonders which would force a re-thinking of almost every aspect of humanity’s conventional wisdom about the heavens, whether one happened to be a geocentrist or a heliocentrist.

He saw that the Milky Way, a hazy band of light that could sometimes be seen snaking across the night sky, was actually made up of thousands of individual stars. This indicated that the stars, previously believed by almost everyone to be mere static points of light on the inner surface of the celestial sphere, lay at wildly varying distances from the Earth in reality. It was strong evidence that Giordano Bruno, who had been brutally executed less than a decade earlier for daring to propose an effectively infinite universe, had been right all along. “All the disputes which have tormented philosophers through so many ages are exploded at once by the incontrovertible evidence of our eyes, and we are freed from wordy disputes upon this subject, for the galaxy is nothing else but a mass of innumerable stars planted together in clusters,” concluded Galileo. “Upon whatever part of it you direct the telescope, straightaway a vast crowd of stars presents itself to view.”

He saw that the surface of the Moon was irregular, a patchwork riot of mountains and valleys. Light from the Sun illuminated the highlands while the lowlands stayed in shadow, just like on Earth. The movement of light and shadow across the Moon’s surface in combination with the Moon’s progress across the Earth’s sky provided further proof that it was the Earth and Moon that were moving, the Sun that was standing still. Galileo realized that the Earth and the Moon were actually not that dissimilar to one another. The Moon was like a smaller Earth, upon whose surface humans could presumably walk, if they could but find a way to get there. Who knew what flora and fauna might already be living in those rugged mountains and valleys?

Most amazingly of all, Galileo spotted more moons — no fewer than four of them, in fact — orbiting around the planet known as Jupiter. One of the philosophical arguments deployed by geocentrists in favor of the Earth’s unique preeminence had long been the existence of the one heavenly body which even the heliocentrists acknowledged was orbiting our planet, a junior companion the likes of which no other planet could boast. Now, Galileo had found that the Earth wasn’t unique in this respect at all. In fact, everything he saw through his telescope indicated to him that our planet wasn’t so different from any of the others, that it may even have been among the less impressive subordinates to the Sun; Jupiter, after all, had been given four moons in contrast to the Earth’s one.

Night after night during the winter of 1609 to 1610, Galileo prowled the bell towers and battlements of Venice and Padua like some nocturnal Nosferatu. A dismaying number of the friends and colleagues whom he convinced to look through his telescope flat-out refused to believe the evidence of their own eyes. “I tested this instrument of Galileo’s in a thousand ways, both on things here below and on those above,” said one of them. “Below, it works wonderfully. In the sky, it deceives one. I have as witnesses most excellent men and noble doctors. All have admitted the instrument to deceive.” It didn’t help that no one, Galileo included, could explain why a convex and concave lens placed one behind the other produced the magnifying effect that it did. In the absence of such an explanation, it was easy for men of a certain mindset to write it off as a trick of the Devil. Throughout human history, paradigms have been stubborn things.

But Galileo was undaunted. He barely slept that winter; while his nights were spent stargazing, his days were spent preparing a pamphlet to reveal his findings to the world. He was in such a rush that he sent its earlier pages to the printer while he was still writing its later ones. For he was well aware that he could hardly be the only one who had thought to turn a spyglass toward the sky. Less than prolific writer though he had been in recent years, he was worldly enough to want the credit and the rewards for the most exciting series of observations in the history of astronomy. He called his pamphlet The Starry Messenger. Unusually for Galileo, but reflecting his ambitions for it throughout Europe, it was written in Latin. As one read it, it gradually became clear that Galileo himself was the titular messenger, a space traveler returned to Earth to share his newfound wisdom with the world. But paradoxically, the Earth to which he had returned was also the spaceship in which he had traveled, pursuing its orbit around the Sun along with all of these other planets which were not so dissimilar to it at all. Galileo had shed his longstanding reluctance to out himself as a Copernican; the pamphlet took heliocentrism as a given, as downright old hat amidst so much else that was new that it had to share.

The Starry Messenger was published on March 13, 1610. It was the polar opposite of Copernicus’s On the Revolutions of the Heavenly Spheres: slim where that book had been fat, a few months in the making rather than a few decades. Its bare 24 pages caused enormous and immediate excitement and controversy in astronomical circles in exactly the way that On the Revolutions hadn’t. The English ambassador to Venice sent a copy home to King James I on the very day it came off the press, calling it “the strangest piece of news ever yet received from any part of the world”: “And the author runneth a fortune to be either exceeding famous or exceeding ridiculous.” As we have already seen, a copy was in the hands of Johannes Kepler in Prague almost as quickly. A second printing proved necessary within days.

The brevity — not to say sketchiness — of the pamphlet must have ironically helped it become so well-known so fast. The big books of Copernicus and Tycho and Kepler had demanded careful attention and no small degree of mathematical knowledge to comprehend. The Starry Messenger was not like that; it could be read and understood in an hour or two by just about anyone.  Some people, among them Kepler, greeted the little booklet with joy. The first instinct of many others was to condemn the message and the messenger in the blackest of terms. According to these stubbornly benighted souls, “the spyglass makes us see things that are not really there. This objection is buttressed by a large number of arguments and proofs, starting with the creation of Adam.”

But regardless, everyone was talking about Galileo Galilei, at age 46 suddenly the most famous astronomer since Tycho Brahe. A fellow scholar at the University of Padua called him a more important discoverer than Christopher Columbus. The great English poet John Donne took up his pen to capture the zeitgeist in all of its disorientation.

And new Philosophy calls all in doubt,
The Element of fire is quite put out;
The Sun is lost, and th’ Earth, and no man’s wit
Can well direct him where to look for it…
‘Tis all in pieces, all coherence gone;
All just supply, and all Relation…
And in these Constellations then arise
New stars, and old do vanish from our eyes.

Johannes Kepler, inordinately pleased that Galileo had finally come loudly and proudly out of the closet with his Copernican beliefs thirteen years after Kepler had first urged him to take that step, published an “open letter” to Galileo in which he too compared him to Columbus, plus Ptolemy to boot. He then wrote Galileo a personal letter, where he admitted that “you have aroused in me a great desire to see your instrument so that at last I too can enjoy, like yourself, the spectacle of the skies.” (Kepler had a way of coming across like a fawning apprentice even when he held the august title of Imperial Mathematician.) Galileo wrote a non-committal missive in return, thanking Kepler for his praise and support but not saying much more. For whatever reason — perhaps still the bad initial impression produced by Kepler’s fanciful first book — Galileo seems not to have valued him especially highly, appears not to have ever even read Kepler’s The New Astronomy. This was a shame, for he could have learned much from it.

For the fact was that Galileo’s heliocentrism still had an all too familiar problem: the math still didn’t really work. What was seen overhead didn’t conform to any abstract system that he knew how to mathematically model. This was because he was still trying to reconcile his heliocentrism with perfectly circular orbits — an unproductive, vexing exercise that had become the one shadow occluding the sunniest days of his life. If he had but read The New Astronomy, it might have been sunshine all around.

Amidst so much that was so new within its pages, it was easy to overlook the most traditional part of The Starry Messenger, a florid dedication directed toward Cosimo II de’ Medici, scion of the first family of Florence, patrons of Michelangelo and so many other past geniuses: “For just as the stars, like children worthy of their sire, never leave Jupiter’s side by much, so — and indeed, who does not know this? — clemency, kindness of heart, gentleness of manner, splendor of royal blood, nobility in public affairs, and excellency of authority and rule have all fixed their home and habitation in Your Highness.” Nauseatingly typical though it may have been in tone, the object of the dedication was an odd one when you thought about it. Why not choose the doge of Venice or some other high-ranking local aristocrat? It seemed that something was in the works.

This was proven to be the case on June 5, 1610, when Galileo was formally invited by Cosimo II to return to Florence as the prodigal son made good. There he would be given the title of “Chief Mathematician of the University of Pisa and Philosopher of the Grand Duke, without obligation to teach and reside at the university or in the city of Pisa, and with a salary of 1000 Florentine scudi per annum.” It went without saying that he would treated as one of the most exalted men of Florence. The prodigal son accepted, selling his house in Padua to move into a far grander one in Florence. Along with his old university position, he left behind his mistress Marina Gamba. (It is possible that one of the reasons he wished to leave Padua was to escape a relationship that no longer pleased him.) He took his two eldest children with him, leaving the youngest in Marina’s care. His former mistress would go on to marry a man closer to her own social station. For his part, Galileo would remain single for the rest of his life.

He kept himself as busy in Florence as he had been of late in Padua. He continued to perfect his telescope, until he had an instrument capable of magnifying human vision by a factor of 30, near the practical limit for a two-lens design such as this. He pointed it at Venus, observing that that planet’s surface was entirely obscured by swirling clouds, and at Saturn, seeing for the first time its uncanny rings, although he had no idea what to make of them. He also saw that Venus went through phases like the Moon, albeit over a much longer period of 584 days, as it and the Earth circled the Sun, shifting position in relation to one another. By now, heliocentrism was so ingrained in him that he hardly thought the subject worth discussing.

He began to experiment with daytime astronomy as well. In the past, observation of the Sun had been hindered by its sheer brightness, which made it impossible to gaze upon directly for more than a second or two if one didn’t wish to be permanently blinded. Galileo mounted a tinted lens on the end of his telescope to dim the Sun’s brilliance. By this means he became the first person ever to examine the Sun at careful length, magnified or unmagnified. What he saw was as astounding as any of his other discoveries: the surface of the Sun was pockmarked with little blemishes — what we call sunspots today — that moved about over time. The Sun was not, in other words, the immaculate beacon of divine light that it had always been thought to be. The more Galileo peered at the sky, the more the heavens revealed themselves to be a messy, constantly changing physical realm like that of Earth, not an ineffable one of permanent perfection.

In March of 1611, Galileo capped off his extraordinary rise in the world by visiting Rome for the second time in his life. He went there in a Medici carriage, wrapped in the aura of a family that, in addition to all of their other achievements, had provided the Church with four popes. He gave demonstration after demonstration of his telescope to the great and the good of Rome. In return, he wrote, “I was too on my part in viewing the marvels of their statuary, paintings, frescoed rooms, palaces, gardens, etc.”

One of those who looked through the telescope was Robert Bellarmine, “the Hammer of the Heretics,” chief instigator of the downfall of Giordano Bruno. Now 68 years old, he had been promoted to cardinal thirteen years ago. He had been seriously scrutinized for elevation to pope once before, and would be once again before all was said and done. In the meantime, he remained what he had always been, a hard-line conservative who believed that the Inquisition should be used with no hesitancy whatsoever to stamp out heresy in all of its aspects and enforce a rigid, intensely traditionalist orthodoxy. As he had demonstrated in the case of Bruno, he had no qualms about employing torture and violence to scourge the bodies of those who strayed, whether as a way of forcing them back onto the straight and narrow or, failing that, in order to make a vivid example of them for the benefit of the rest of the laity.

Loudly reverberating events in history often begin quietly. Cardinal Bellarmine looked through Galileo’s telescope in April of 1611 and listened politely as the astronomer explained to him the new truths it had revealed and the slightly older one — namely, the theory of heliocentrism — that it had irrefutably confirmed. The next day, Bellarmine sent a letter to the Roman College, asking the scholars there for their opinion of Galileo’s bold claims. The replies he got back were cautious, but generally agreed that many of the findings and the extrapolations therefrom made sense. Perhaps thinking back to the fate of Bruno, the professors showed the most skepticism toward Galileo’s claim that the Milky Way full of stars served as evidence of an infinite universe. Nor were they all ready to say that Galileo had definitively proven that the Earth moves around the Sun, although they were forced to admit that Venus must do so; some of them persisted in clinging to Tycho Brahe’s hybrid model as a last hedge against heliocentrism.

For the time being, Cardinal Bellarmine remained publicly noncommittal. He raised no objections even when Galileo was accorded the ultimate honor of an audience with Pope Paul V. Coming from the House of Borghese, a noble clan to rival the Medici in wealth and power, Paul was a papal maximalist even in comparison to his immediate predecessors, wielding the Inquisition and the writ of excommunication as his sword and shield. He took to heart his namesake saint’s warning in the Bible that “of your own selves shall men arise, speaking perverse things, to draw away disciples after them.”  He believed that it was laxity toward such heretics that had led to the rise of Protestantism, the greatest threat to the One True Church since ancient times. He was of course reinforced in this point of view by Cardinal Bellarmine, who, his own near miss of the papacy notwithstanding, was as close to Paul V as he had been to Clement VIII. An imperious figure in private and in public, Paul would soon dare to place his own name on the façade of Saint Peter’s Basilica, in a Latin inscription that is still seen by hundreds of millions of visitors every year: “Paul V Borghese, Roman, Pontiff, in 1612, the seventh [year] of his pontificate, in honor of the Prince of Apostles.”

Galileo was not as overawed by his invitation into the Holy Father’s presence as many another man might have been. Since his youthful flirtation with holy orders, he had drifted further and further away from the active practicing of religion. He never spoke out against it — that would be tantamount to suicide in seventeenth-century Italy — but he seldom attended Mass either. In general, he appears to have paid the Church as little lip service as he thought he could get away with. His 21st-century biographer David Wootton notes that

it really is a striking fact that in hundreds of letters written by Galileo that survive there are absolutely no spontaneous expressions of piety — such expressions occur only when he himself has been charged with impiety. And there are no attempts to invoke the ordinary, almost routine miracles that formed a part of Counter-Reformation spirituality. Galileo never praises preachers, prays to saints, or purchases indulgences. Now and again there is a glimpse of him going to church, even listening to a sermon — but his thoughts are elsewhere. All of this, you may say, is an argument from silence. I agree. But in the end Galileo’s silence becomes so remarkable that we simply cannot ignore it. There is simply no direct testimony to what he thought of Christ.

It is this quality, perhaps more than any other, that led Arthur Koestler to describe Galileo as “wholly and frighteningly modern.” He really does seem to have been a man without religious faith, an incredibly rare — and dangerous — thing to be in sixteenth-century Europe.

For this very reason, as he prepared for his meeting with the pope, he likely saw him more as just another man of rank and power — a potential worldly benefactor — than as God’s chosen representative on Earth. It was just a matter of going through the pro-forma rituals that were so much a part of life in this time and place. Thus he must have been pleased when the Venetian ambassador to Rome informed him “that I had been treated with exceptional favor because his Holiness would not let me say a word while kneeling, but immediately commanded me to stand up.” On the whole, the meeting was a bit perfunctory, but cordial enough. Mission accomplished.

Galileo left Rome on June 4, 1611, after having been feted and praised to a gratifying degree over the foregoing two and a half months. The misgivings that some in Rome felt toward his discoveries and opinions could as yet be discerned only as a low background hum behind the dominant note of adulation. By way of summing up the visit, one cardinal — not Bellarmine — wrote that “Galileo has, during his stay in Rome, given great satisfaction, and I think he received as much, for he had the opportunity of showing his discoveries so well that the learned and noble in this city all found them no less true and well-founded and astonishing. Were we still living under the ancient Republic of Rome, I am certain that a statue would have been erected in his honor on the Capitol.” Even in this age when Europe was steadily creeping out from under the shadow of antiquity, to be compared with the ancient luminaries was still high praise indeed.

But not everyone was so uniformly pleased. Cardinal Bellarmine told the Tuscan ambassador to Rome privately that he was glad to see the back of Galileo, saying that “he did not like Galileo’s doctrine. Cardinal Bellarmine told me that great respect was owed to all matters pertaining to the Medici, but that if Galileo had stayed in Rome longer, he would have been forced to offer some justification for his ideas.” These were ominous words to anyone who knew what Bellarmine’s definition of “justification” entailed. Suffice to say that it often involved the tortures of the Inquisition.

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