The real and complex story

Galileo’s condemnation: The real and complex story

McMullen, Emerson Thomas


Often the Catholic Church’s condemnation of Galileo Galilei is viewed as the prime example of an ongoing “war” between science and religion. Just as often the reason for this condemnation is thought to be Galileo’s advocacy of Copernicanism. The true story is much more complex than these assumptions. Firstly, modern historians of science do not accept the “warfare” thesis of science versus religion. Secondly, Galileo’s claim that each planet orbits an imaginary point that, in turn, orbits another imaginary point near the sun, may not have been the root cause of his troubles with the Church. The reasons behind Galileo’s sentence are complex. There are several factors besides Copernicanism. One is angering his friend, Pope Urban VIII. Recent documentary discoveries indicate that another factor was Galileo’s advocacy of atomism, which undermined the Church’s scientific understanding of the Eucharist.

Key words: Galileo Galilei, Copernicanism, Atomism, Eucharist, Popes Paul V and Urban VIII, Cardinal Robert Bellarmine, Johann Kepler


A pervasive idea in much of our culture is that science and religion inherently conflict with one another. However, most modern historians of science do not share that idea. For them, this claim is unsupported and dated (1). Similarly, the popular cultural view of Galileo’s treatment at the hands of the Catholic Church is often distorted. This article analyzes the interaction of Galileo, science, and the Church, and shows just how complex it was.

Historians and Galileo

Of the books and analyses of Galileo Galilei’s condemnation, one of the most interesting is Pietro Redondi’s Galileo: Heretic (1987) (2). In 1982, Redondi discovered a document, labeled “G3,” which contains an accusation concerning Galileo’s atomism (3). The danger of atomism in Galileo’s time was that it conflicted with the Church’s Aristotelian explanation for the Eucharist in which bread and wine miraculously turn into the body and blood of Jesus Christ. Catholic theologians used Aristotle’s physics to explain that, while the substance of the bread and wine changes, the qualities do not. This scientifically-based idea became Church dogma, and therefore could not be questioned without challenging the Church’s authority. Basically, Redondi argues that the promotion of atomism and its threat to the Church was the real reason for Galileo’s condemnation. Copernicanism merely was the cover for it.

Historians of science did not readily accept Redondi’s theory when he proposed it in the 1980’s. This included the excellent one I studied under, the late Richard Westfall. He pointed out that the last mention of atomism was in Galileo’s Assayer, published in 1623, but Galileo’s condemnation occurred a decade later in 1633. The timing did not seem to fit. This rationale however, has been counted by the discovery, in November 1999, of a new document in the same archive as G3, labeled EE291. It is a working paper that discussed the charge of atomism against Galileo. Handwriting analysis indicates that a member of a special commission the pope formed to investigate Galileo wrote it in 1632 (4).

I conclude from the new evidence that the atomism charge was one of many factors that led to Galileo’s condemnation. The other factors were that Galileo was obsessed with Copernicanism as the actual structure of our Solar System, appeared to have disobeyed an injunction, made a number of enemies who were more influential than he thought, was insensitive to the current political situation, advocated his personal interpretation of the Bible against Catholic authorities, and antagonized his friend, the pope.

In spite of the above, what we tend to hear is that Galileo’s scientific stance on Copernicanism that was the basis of his condemnation. So let us look at the scientific background, starting with the structure of the universe.

The Structure of the Universe

Early Greek philosophers, like many thinkers before them, gazed into the night sky and decided it appeared to be shaped like a dome, a hemisphere. They concluded that the entire shape of the starry heaven is spherical. They came to think of the stars as attached to the sphere. As this giant orb rotated around a stationary earth, the stars traced out circular paths, which were thought to be perfect motion. One exception was the Pythagorean idea that the earth moved. Aristotle attacked this idea and instead worked out a geocentric system of more than fifty rotating and counter rotating crystalline spheres. His machinery caused the sun, moon, planets and stars to move “perfectly,” that is, in unchanging circular courses. Aristotle’s science was so comprehensive that it came to dominate intellectual thought up to the Scientific Revolution.

As astronomers gathered more data, they realized that they needed new explanations to account for the observed paths in the sky. Claudius Ptolemy (2nd century A.D.) answered this growing problem with a system of epicycles, equants, and eccentrics that accounted for appearances. Still, he preserved Aristotle’s circular motion as seen in Figure 1. This system worked wonderfully for predicting future planetary positions and calculating past ones, but is it scientifically real (5)? Does each planet actually circle its own imaginary point in space, and does this imaginary point circle yet another imaginary point in space? This second center of circular motion is offset from a motionless earth and is called the eccentric. Thus the correct name for Ptolemy’s system is not geocentric, as it is usually called, but geostatic.

Aristotle’s illusory machinery of rotating crystalline spheres is driven by an unmoved mover. But what in Ptolemy’s system make his planets circle empty centers, and what makes these empty centers circle other empty centers? Some supernatural being? Another problem for Ptolemy is that in his system, the moon is constantly moving close to, and then away from, the earth as it makes its monthly rounds. Yet no one observes this to-and-fro movement occurring in nature. Ptolemy’s geostatic system may not have been scientifically real, but the calculations based on it worked, and therefore Arabic thinkers called it “The Greatest.”


Nicholas Copernicus (1473-1543) was a canon in the Catholic Church and trained in medicine. He thought God had made the Universe efficiently, harmoniously, and orderly. Therefore, Copernicus eliminated Ptolemy’s equant and switched the earth’s position with the sun’s. However, Copernicus retained the eccentrics and epicyclic planetary motion, as shown in Figure 2. Since the sun is offset from the centers of motion, this is not a true heliocentric configuration, thought it is usually called that. More correctly, it is a heliostatic system.

Copernicus was aware that he would be criticized by Aristotelians in the Church and without. In his dedicatory letter to Pope Paul III, he claimed that his idea was not that unique, because the Pythagoreans and other ancients had held that the earth moves. In addition, Copernicus pointed out that Lactantius (c. 240 – c. 320), who was called the “Christian Cicero” by Renaissance Humanists, “speaks quite childishly about the earth’s shape when he mocks those who declared that the earth has the form of a globe (6).” Thus, Church theologians, even well-respected ones, could be in error concerning the physical world. Finally, Copernicus cited supporters for his idea within the Church, Nicholas Schonberg, Cardinal of Capua, Tiedemann Giese, Bishop of Chelmno, and “not a few other very eminent scholars (7).”


One of the greatest astronomers of the time was Tycho Brahe (1546-1601). Brahe’s beyond-the-state-of-the-art instruments showed no stellar parallax. In other words, he saw no evidence that the earth was moving in an annual orbit. Copernicus had been aware of this problem and argued that the stars were about forty times more distant than previously thought.

Brahe’s extremely accurate measurements indicated that the stars had to be more than 700 times further in order to not observe parallax. Brahe could not accept that result. It meant that the universe was more than 300 million times what it would be if the earth did not move. Why would God have created all that wasted space (8)? Brahe therefore developed his own system in which the moon, sun, and stars rotated around a geocentric earth, but the planets rotated around the sun. In this system, there are no imaginary centers of rotation and, considered as a model, it made accurate predictions.


Johannes Kepler (1571-1630), laboring tirelessly with Brahe’s treasure trove of accurate data, finally deduced that the planets go in elliptical orbits with the sun at one focus of the ellipse. He published this finding in 1609, along with another planetary law, in his New Astronomy (9). He apparently sent a copy to Galileo and then waited expectantly for a reply or at least an acknowledgment, but it never came (10). We know from a 1612 letter to him that Galileo was aware of Kepler’s findings on planetary motion, but he ignored them (11).

Kepler additionally argued that the planets resembled the earth in being material bodies. This is something that Galileo would later claim for the moon. Kepler also correctly argued that the moon caused the tides, not the earth’s rotation. Galileo would wrongly assert that tidal motion proved that the earth moved.

Like Copernicus, Kepler was aware that there would be criticism of his system and offered lines of defense. As did Copernicus, Kepler, in the Introduction of his New Astronomy, refers to Lactantius’ error while at the same time calling him pious. To this argument, Kepler adds “pious St. Augustine,” who wrongly denied the antipodes in The City of God. No shrinking violet, Kepler also refers to the “pious Inquisition,” which wrongly denies the earth’s motion!

Kepler’s Interpretations

Kepler so skillfully handles the scriptural objections to the earth’s motion that his analysis became the most widely translated and read of his writings. “Now the Holy Scriptures,” he writes, “speak with humans in the human manner.” Using this as a guide, he starts with Psalm nineteen, which happens to be the first one that would be quoted against Galileo. Kepler asks “Who is unaware that the allusion in Psalm 19 is poetical?” Referring to verses four and five, he comments that “Here, under the image of the sun, are sung the spreading of the Gospel and even the sojourn of Christ the Lord in this world on our behalf, and in the singing the sun is said to emerge from the tabernacle of the horizon like a bridegroom from his marriage bed, exuberant as a strong man for the race (12).” The allusion has nothing to do with any physical reality, it is a poetic rendering.

Next, Kepler addresses the passage in the book of Joshua where the sun seems to the observer to stand still. Kepler explains that because it appears that way, men think the sun is small and the earth large, and that the small sun moves around the earth large, hence Joshua’s request. “For if someone had admonished him that the sun doesn’t really move against the valley of Ajlon, but only appears to do so, wouldn’t Joshua have exclaimed that he only asked for the day to be lengthened, however that might be done?” Kepler argues that, “Now God easily understood from Joshua’s words what he meant, and responded by stopping the motion of the earth, so that the sun might appear to him to stop (13).” The need for more daylight is what the passage is about, not the structure of the universe.

Kepler goes on to discuss of Genesis 1, Jeremiah 22, and Job 38. Then he gives a counterexample: “Suppose someone were to assert, from Psalm 24, that the earth is founded upon rivers, in order to support the novel and absurd philosophical conclusion that the earth floats upon rivers (14).” It is obvious that “the psalmodist intends nothing but what men already know and experience daily, namely that the land, raised on high after the separation of the waters, has great rivers flowing through it and seas surrounding it.” There is no need to be so literal here or in Psalm 137 in which the same figure of speech is adopted and “the Israelites sing that they were seated upon the waters of Babylon, that is, by the riverside, or on the banks of the Euphrates and Tigris. If this be easily accepted, why can it not also be accepted that in other passages usually cited in opposition to the earth’s motion we should likewise turn our eyes from physics to the aims of scripture (15)?”

Next, Kepler quotes from Ecclesiastes 1:4. “A generation passes away and a generation comes, but the earth stands forever.” He asks: “Does it seem here as if Solomon wanted to argue with the astronomers?” Kepler answers by calling attention to the subsequent verses: “No; rather, he wanted to warn men of their own mutability, while the earth, home of the human race, remains always the same, the motion of the sun perpetually returns to the same place, the wind blows in a circle and returns to its starting point, rivers flow from their sources into the sea, and from the sea return to the sources, and finally, as these men perish, others are born. Life’s tale is ever the same; there is nothing new under the sun.” Kepler argues that there is no physical dogma here; the message is a moral one. Solomon, Kepler concludes, “by mentioning what is evident to all, warns of that which almost everyone wrongly neglects. (16).” So this passage is like the others. While there is an allusion to physical reality, the thrust of these passages is about something else other than any physical reality. Galileo made little or no reference to these arguments. This was the same situation we already saw with Kepler’s scientific discoveries.


Why did Galileo ignore Kepler’s and Brahe’s scientific work? They had the most accurate and numerous observations of anyone at that time. One could claim that Galileo’s telescopic discoveries superseded Brahe’s data, but then why would Galileo champion Copernicus, whose observations were fewer and more dated?

In the dedication of his Dialogues on the Two World Systems (1632), Galileo called Ptolemy and Copernicus the greatest minds ever to have philosophized about the structure of the universe. This immediately raises the question about why he left out Brahe and especially Kepler. In a 1624 letter, Galileo referred to Brahe and Kepler as heretics (17). This could be the reason Galileo slighted them and advocated the veracity of Copernican epicycles over Kepler’s elliptical orbits or Brahe’s system (18). Another reason might be that Galileo could not break away from the perfection of the circle that had influenced the thinking of all the ancient philosophers (19).

Some authors have alluded to Kepler’s “mystical” thinking and speculated that this may have been the reason why Galileo was wary of Kepler (20). However, this is an unwarranted twentieth-century criticism. In reality, Galileo had taught students how to cast horoscopes, and on several occasions he cast them himself. In January 1609, he reviewed the horoscope for the ailing Grand Duke Ferdinando. He predicted many more happy years, but the Grand Duke died of his illness just three weeks later (21). This experience no doubt made Galileo more skeptical of astrology, but my point is that mysticism was no stranger to Galileo or his times, and therefore is not a valid explanation for why Galileo rejected Kepler.

Galileo’s Anti-Aristotelianism

Flushed with the success of his telescopic findings (1610), Galileo busily began promoting the Copernican system and attacking those aspects of Aristotelian science he had shown wrong. One error concerned Aristotle’s theory of light, which did not explain the newly discovered property of barium sulphide. Alchemists called this mineral a “solar sponge” because it absorbed light and then glowed in the dark. This property suggested to Galileo that light was not a quality as Aristotle thought, but rather, it consisted of invisible corpuscles. Here is the source of Galileo’s atomism. Besides his advocacy of Copernicus over Aristotle, Galileo’s study of falling bodies caused him to begin questioning Aristotle’s theory of motion.

In 1612, Galileo put his verbal attacks on Aristotle into print with the Discourse on Floating Bodies. In 1613, with the publication of his letters on sunspots, Galileo continued supporting Copernicanism and attacking Aristotle. He also ridiculed a Jesuit scientist, Christopher Scheiner, in a priority battle over sunspots. This polemic brought a growing reaction from the Jesuits at the influential Collegio Romano.

In spite of warnings in 1615 from high-placed friends in Rome, Galileo persisted in promoting Copernicanism (22). He appeared to be deaf to their pleas. The Tuscan Ambassador in Rome, Piero Guicciardini, hosted Galileo in early 1616 and witnessed his single-minded drive for Copernicanism, now bolstered by Galileo’s new theory that the tides proved that the earth moved. Guicciardini wrote to the Grand Duke about Galileo: “He is passionately involved in this fight of his and 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 as it is impossible, when he is around, to escape from his hands (23).” If the Ambassador’s assessment is correct, and assessments were what he was expected to do well, then Galileo appears not as a disinterested scientist, but as a zealous advocate, so obsessed with Copernicanism, that he was blinded to both scientific objectivity and political realities.

The Injunction

The whole affair eventually came to a head. Among others, Tommaso Caccini, a Dominican monk, accused Galileo of contradicting the Scriptures. This was in a 20 March 1615 deposition to the Congregation of the Holy Office (or Inquistion) in Rome. These accusations brought him under examination by the most influential person in the Vatican after the pope, Cardinal Robert Bellarmine. Galileo was aware of this and sent the Cardinal his own deposition.

The Inquisition’s investigation of the charges turned up nothing serious. The consultant who examined a supposedly heretical letter reported that it did not depart from Catholic doctrine. Other lines of investigation also turned up nothing. The Inquisition asked a committee of eleven experts to examine Galileo’s ideas (24).

Bellarmine had taken action on his own. He apparently consulted with Jesuit astronomers who correctly informed him that, while Galileo had shown Ptolemy’s system was wrong, he had not proven that Copernicus’ was right. Also, Galileo’s discoveries had not eliminated Brahe’s geocentric system, and some of the Jesuits were favoring it (25). Bellarmine then received the report from the committee of eleven consultants. They were of the unanimous opinion that Copernicanism was wrong philosophically as well as theologically erroneous. Here was something to act on.

On 25 February 1616, Pope Paul V ordered Bellarmine to warn Galileo to back off from his Copernican views. The next day Bellarmine called Galileo to his house and apparently gave him an injunction. It appears that, with others present, Bellarmine warned Galileo, in the name of the pope, not to hold, or defend the opinion that the sun is the center of the universe and that the earth moves.

Officially, the Congregation of the Index (or Prohibited Books) ordered corrections to be made to Copernicus’ book, and took other actions concerning the matter. This included completely suppressing Carmelite Father Paulo Foscarini’s book advocating Copernicanism. However, famous Galileo met with Pope Paul, who assured him that he had not been on trial and not condemned. Later, Galileo asked Bellarmine for a memorandum of the meeting to show that he had not been condemned. This document did not fully enjoin Galileo, but the earlier warning was clear. He followed orders and restrained himself, even though a decree from the Index did not have the weight of one from the pope or a council, such as the Council of Trent.


In the meantime, Kepler had published on comets (De cometis) and about his third planetary law (Harmonice mundi), both in 1619. Yet Galileo continued to ignore Kepler’s revolutionary scientific discoveries, again to his detriment. Galileo’s fight over comets was prompted by the publication of a lecture on the subject by another Jesuit, Orazio Grassi.

Grassi, it turns out, was much more correct about comets than Galileo, who had observed only one comet in his life and that was when he was just thirteen years old (26). Later in 1619 Galileo wrote Discourse on Comets in which he argued that comets were purely optical effects due to refractions in the atmosphere. Interestingly, Aristotle also taught that comets were atmospheric phenomena. On the other hand, Grassi supported the view advocated by Tycho Brahe that comets were real phenomena. Further, Brahe’s measurements showed cometary paths were beyond the moon’s orbit, and Grassi had added to these. In December 1619, Grassi replied to Galileo in The Balance between Astronomy and Philosophy. A battle royal was brewing between the two.

Many in Rome disliked the Jesuits and appealed to Galileo to put them in their place. Among these were Prince Cesi and members of his Academy, who offered to publish whatever Galileo wrote. The hype, the prepublication publicity, and high-level support made Galileo’s The Assayer (1623) a success even before it was published (27). The book is well written and a page turner, even if the astronomy is not that good. Again Galileo promoted atomism and discussed the nature of light in it. Just before publication, a friend of Galileo’s, Mafeo Barbarini, became Pope Urban VIII and so The Assayer was hurriedly dedicated to him.


While these events were occurring, Bellarmine died. With that, and the ascension of Urban VIII, Galileo decided to test the waters, so to speak, for another plunge into Copernicanism. The Tuscan Ambassador was correct. Galileo was worked up over the matter and passionately involved in the fight. Comets and atoms would have to wait. Urban VIII was also a Florentine, an admirer of Galileo, and had even written a poem for him (28).

Urban had none of the aversion to Copernicanism that his predecessor had. he seems to have thought that any astronomical theory could never be proven true. He interpreted the decree of the Index to mean that discussion of the earth’s motion required special care and diligence (29). He gave Galileo six private audiences in 1624, which naturally included a discussion of the structure of the universe. Urban encouraged Galileo to write about it. Galileo welcomed the opportunity to get back into the battle over Copernicus. The result was the Dialogue on the Two Great World Systems (1632).

While Galileo was writing the Dialogue, an interesting conversation occurred between Urban and Tommasso Campanella in 1630. Campanella told the pope “that he had had the opportunity to convert some German gentlemen to the Catholic faith and they were very favorably inclined; however, having heard about the prohibition of Copernicus, etc., they had been scandalized, and he had been unable to go further.” Urban answered “with the following exact words: ‘It was never our intention, and if it had been up to us that decree would not have been issued’ (30).” One has to wonder who the “our” and “us” refers to in the pope’s reply. It could be the “us” is himself and therefore it is a royal personage referral. However, he was referring to a time when he was not pope, and so perhaps it was not a magisterial use. Thus, there may have been a faction opposed to the Index’s decree concerning Copernicanism. And, according to Urban, if that group had had more influence, there would have been no decree at all. If so, then the influence of this faction is probably why the decree ended up coming from the Index rather than a higher authority such as the pope. Whatever he meant by “us,” the important thing is that Urban had no problems with Copernicus’ system. Given this, then we have to puzzle over exactly why Galileo got into so much trouble with the pope and the Church.

Campanella had found favor with Urban and certainly had a sympathetic ear for what the pope was saying. While in prison Campanella had written a defense of Galileo (c. 1616) that was later published in 1622. The first of eleven arguments was that since there was no theological problem when Copernicus first published his book, why are there problems now? Next, he pointed out that the book was dedicated to the pope at a time when “distinguished genius flourished within the Church.” Third, Erasmus Reinhold, John Stadius, Michael Maestlin, Christopher Rothmann and many others accepted the theory, including The Imperial Mathematician, Kepler, and the Englishman William Gilbert. And so it went (31). Given that this was so, we again ask why did Galileo get into so much trouble with the pope and the Church?

A Dangerous Dialogue

Some think that Galileo used a rhetorical approach in his Dialogue because he knew he had no proof that Copernicanism was real (32). However, it is clear that Galileo believed Copernicus’ epicyclic heliostatic system was real. In his Letters on Sunspots, Galileo stated, “I am quite sure that there exist circular motions which describe eccentric and epicyclic circles (33).” In a later letter he asserted that eccentrics and epicycles “must be accepted with absolute necessity (34).”

Even though Bellarmine’s 1616 injunction carried the warning of Pope Paul V with it, many thought that, in the Dialogue, Galileo was arguing for the reality of Copernicanism. Nevertheless this was disobedience, not heresy. After the sound and fury were over, Descartes calmly wrote that no pope or council had declared Copernican theory heretical (35). He is right, so why allude to heresy in the trial? The answer is that there was more at stake than Copernicus’ theory. What was at stake was the Church dogma concerning the Eucharist, a fact troubling to the pope and both troubling and useful to the Jesuits.

Although the Jesuits had sided with Galileo at the time of his injunction, now they were the important part of a group bent on “getting” Galileo. It appears that Grassi led the Jesuit assault. Pridefully, Galileo seemed to go out of his way to humiliate, alienate, and attack people. It is not surprising that he had made enemies like Grassi, who wished to return Galileo’s treatment of them with interest. These enemies had personal, as well as professional, reasons for wanting to humiliate Galileo, and were not above using the power of the Church to extract their revenge.

No doubt it was the attacks of the Jesuits that aroused Urban to action. When the pope summoned him to Rome, Galileo wrote in a 15 January 1633 letter that “from reliable sources I hear the Jesuit Fathers have managed to convince some very important persons that my book is excerable and more harmful to the Holy Church than the writings of Luther and Calvin (36).” It appears that the Jesuits successfully raised the issue of atomism undermining the Eucharist, which the Church did not want to publicize. Urban especially did not want the publicity, as he was being accused at that time of being spiritually lax. Whether he wanted to or not, the pope had to defend Galileo against this charge.

A Pope Under Pressure

Urban had been elected pope primarily because of the backing of the French cardinals. He repaid the favor to France, much to Spain’s displeasure. Then the French sided with the Protestants when the King of Sweden was going from victory to victory in the Thirty Years War. The Spanish faction of the Church became extremely upset, and on 8 March 1632, Cardinal Caspare Borgia, the Vatican ambassador to Spain, officially censured the pope. Urban reacted in a somewhat paranoid manner. He suspected a Spanish intrigue against him, and even feared he would be poisoned. He tried to root out those around him whom he thought might be part of any Spanish plot. This put some of Galileo’s supporters under suspicion. Galileo did not help things by naively negotiating with the Spanish Admiralty about his method for finding longitudes (37), but then he really erred.

In one of those earlier six audiences with Galileo, Urban had given his position on God and the universe. He thought that men had very limited logic as far as grasping the workings of the universe was concerned. Thus, to argue that God created the universe any one particular way was to limit God’s power. This was why the pope was not particularly bothered by Copernicanism. God could have created the Cosmos any number of ways, so who are we to say how he did it? In this, Urban may have been following the ideas of Michel Montaigne concerning the limitations of the human mind.

Galileo thought differently – he had greater confidence in man’s reasoning than either the pope or Montaigne. At the close of his Dialogue, Galileo put the pope’s view of the universe in the mouth of Simplicio, the Aristotelian simpleton. Simplicio states that this view “I once heard from an eminent and learned person [that is Urban VIII] and before which one must fall silent (38).” The pope was both a man under pressure and a man not to ridicule, but it looked to him as if Galileo had done just that (39). We will see that Urban was angry over this, as well as other difficulties.

A Betrayed Pope

When Urban became Pope, Prince Cesi came to congratulate him. Urban interrupted him, eagerly asking “Is Galileo coming? When is he coming (40)?” When Galileo did come, Ruban showered him with gifts, including pensions for him and his son, Vincenzio. But now, with Simplicio mouthing the pope’s reasoning about God and the universe in the Dialogue, it looked as if Galileo had bitten the hand that fed him. This was not the expected attack from a known enemy; it was a stab in the back from a friend to whom he had shown favor and admiration.

Coming in the middle of the Thirty Years’ War and along with many other political difficulties, the timing of The Dialogue was terrible for Urban. He needed his friends to rally around him, but instead he was forced to defend Galileo. So, rather than using the normal bureaucratic machinery of the Inquisition, Urban took the unusual step of convening a special commission to investigate the matter. This was in the summer of 1632. At this same time, the Jesuits issued an official condemnation of atomism within their order (41).

Melchior Inchofer, one of the members of the pope’s commission, recommended that the charge of atomism be added to the others. He wrote concerning The Dialogue that “If the author [Galileo] understands the smallest particles as sensible species, he will find some supporters in ancient philosophy, but he will have to affirm many things that are absurd…” and that “Such an opinion is absolutely contrary to faith, for instance in the case of the Eucharist (42).” In the end, the pope headed off the atomism charge and kept this explosive situation contained.

In the middle of all this, the Grand Duke of Tuscany attempted, via his ambassador, to apply political pressure on behalf of Galileo. At a 4 September 1632 meeting, Urban spelled out his views to the Tuscan Ambassador (who was also a friend of Galileo). The ambassador reported that what transpired was “in a very emotional atmosphere.” The pope said that he had “used every civility with Mr. Galilei, … [and] used better manners with Galileo than the latter” had used with him. This remark may refer to Galileo putting his argument about the universe in the mouth of Simplicio.

When the ambassador’s interview touched the delicate subject of the Holy Office, he said the pope “exploded into great anger and suddenly he told me that even our Galilei had dared entering where he should not have, into the most serious and dangerous subjects which could not be stirred up at this time.” Here the pope must have been referring to the charge that Galileo’s atomism undercut the Church’s teaching on the Eucharist, since he was not concerned about Copernicanism. Galileo’s popularity would insure that researchers would seriously investigate atomism. With his troubles within and without the Church, a threat to the Eucharist was the last thing Urban needed at that time. Finally, several times the pope told the Tuscan Ambassador he had been deceived by Galileo as well as those who had approved the Dialogue (43). This may be Urban’s main heartache: Galileo, his friend, had deceived him.

Damage Control and Galileo

In order to limit the damage to the pope, Galileo’s trial by the Inquisition centered around what was already known – his contention that the earth moved around a fixed sun. This latter position appeared to some to contradict Scripture. For example, Psalm 18 (19 in Protestant Bibles) could be interpreted to say that the sun moves, while Psalms 92 (93) and 103 (104) stated the earth was fixed. Galileo and his supported discussed this difficulty, especially concerning Psalm 18, in their correspondence. For instance, Galileo made a speculative analysis of this Psalm in his 23 March 1615 letter to Monsignor Piero Dini, a minor Vatican official. To promote his desired outcome, Galileo basically argued that statements in the Bible about nature should not guide science. In support of this contention, he quoted Cardinal Baronius “That the intention of the Holy Ghost is to teach how one goes to heaven, not how heaven goes (44).” Earlier we saw that Kepler handled these passages in a more specific manner. Was Galileo just generalizing Kepler? Some of Aristotle’s science had been discredited by Galileo. But Aristotle’s observation that “It is not the facts which divide men but the interpretation of the facts,” came to haunt Galileo (45). Aristotle applied this to science, but it could very well apply to Galileo and the Bible. The Council of Trent had decreed that “no one, relying on his own judgment, …shall dare to interpret them [the Sacred Scriptures] contrary to that sense which the Catholic Church has held (46).” Thus, Galileo’s attempts to interpret the Scriptures only heightened his problems with the Catholic authorities.

Concerning the injunction, Galileo defended himself before the Inquisition by producing the document given earlier to him and signed by Bellarmine. It said only that Galileo had been informed about the censure of Copernicanism. The Inquisitors had an unsigned document that said Bellarmine had ordered Galileo not to hold or defend Copernicanism. Because their document was unsigned, the Inquisitors’ case was weaker. All of the pope’s damage control and maneuvering with the special commission was on the verge of falling apart. The trial was abruptly adjourned and the pope informed. This is where events took a sudden turn.

Some two weeks later, the judge met privately with the accused. It was unprecedented – there were no lawyers, chancellors, or witnesses (47). There is no record of what transpired. It would seem that Galileo was informed of the big picture, and why it was necessary that he be tried and found guilty concerning only Copernicanism. Whatever was said, Galileo reversed his defense. He reported that he had reread the Dialogue and realized that in fact, he had inadvertently defended Copernicus’ theory. In a sense it was like a plea bargain – confessing to a lessor offense to avoid being charged with the greater one (48).

Everything was back on course again, but there remained the pope’s anger at being betrayed. The pope had done his best to protect Galileo from his enemies, but who could protect Galileo from the pope? Urban ordered that the aged and sick Galileo be threatened with torture to ascertain his motives, although no torture was ever used on the still-famous Galileo. Galileo stuck to his claim that his motives were pure.

That done, the Inquisitors found Galileo guilty of vehement suspicion of heresy. This mention of heresy supports Redondi’s atomism theory since Copernicanism was not heretical. They ordered him to recant and to recite the penitential Psalms once a week for three years. He was also placed under house arrest, possibly at Urban’s insistence. When Galileo recanted, he said that he erred due to “vain ambition.” he quoted Cicero: “I am more desirous of glory than is suitable (49).” Now under house arrest, Galileo completed Two New Sciences, which was his greatest contribution to science.


Galileo’s problems were as much from going against Aristotelian science as the Church. It is always an uphill fight to overturn the old paradigm, and Galileo’s science was mixed. On the plus side, he had made new telescopic discoveries and more correctly understood sunspots than did Scheiner. Nevertheless, there were some problems. First, even though he never observed any comets through his telescope or made any measurements, he wrongly argued against Grassi that they were not real. And against Brahe’s measurements, he claimed comets were atmospheric phenomena. Next, Galileo promoted an outdated astronomical theory that involved epicycles, while ignoring Kepler’s system that more correctly used ellipses for planetary orbits. Finally, Galileo wrongly argued that the tides proved the earth’s motion, and again ignored Kepler’s correct explanation that the moon caused the tides. Only under house arrest did Galileo make his greatest contribution to science, the physics of motion.

Galileo’s difficulties developed from many sources. One was his advocacy of atomism, which conflicted with church dogma on the Eucharist and may have led to the suspicion of heresey verdict. Other sources of his problems were his obsession with Copernicanism, needlessly creating enemies, disobeying Bellarmine’s injunction, ignoring the pope’s sensitive political situation, encroaching on the Church’s prerogative of Scripture interpretation, and finally, personally antagonizing the pope, who was his friend.


I thank Tom Africa, Charles Briggs, Kathleen Comerford, Dan and Kathy Skidmore-Hess, and anonymous reviewers for their comments, and William Shea for his translation of Document EE291. Figures 1 and 2 are from Alexandre Koyre’s The Astronomical Revolution, trans. by R.E.W. Maddison (Paris: Hermann, 1973) pp 60-61.


1. Finocchiaro MA: Science, religion, and the historiograpnhy of the Galileo affair; on the undesirability of oversimplication. Osiris, Second Series, 16: 114-132, 2001. Wilson DB: The historiography of science and religion. In The History of Science and Religion in the Western Tradition: An Encyclopedia Ferngren, Ed) New York: Garland Publishing, Inc., pp 3-11, 2000. Brooke J and Cantor G: “Reconstructing Nature, The Engagement of Science and Religion.” Oxford: Oxford University Press, pp 106-138, 1998. Brooke JH: Religious belief and the natural sciences: mapping the historical landscape. In Facets of Faith and Science, Volume I: Historiography and Modes of Interaction (van der Meer, Ed) New York: University Press of America, Inc., pp 1-26, 1996. Kaiser CB: Scientific Work and its Theological Dimensions: Toward a Theology of Natural Science, Ibid, pp 223-246. Lindberg DC and Numbers RL: Eds: “God and Nature: Historical Essays on the Encounter between Christianity and Science.” Los Angeles: The University of California Press, 1986.

2. Pietro Redondi argues the key issue was Galileo’s atomism. See his “Galileo: Heretic.” New Jersey: Princeton University Press, 1987.

3. G3 is in the Archive of the Sacred Congregation for the Doctrine of the Faith, Rome. Ibid, p 333.

4. Artigas M: Shedding new light on the Galileo affair. Rsch News & Oppor in Sei and Theol 2:1, 13, 2002.

5. By using the term “scientifically real,” I am referring to scientific realism as it is currently debated in the philosophy of science. Paul Thagard of the University of Waterloo, Ontario, Canada, defines it as “the view that science aims to produce theories that are at least approximately true, along with the claim that it often succeeds in doing so.” See his review of Bas C. von Fraassen’s “The Empirical Stance,” titled Empiricism, Realisms, and Religion. Science 298: 971, 2002.

6. Copernicus N: Six Books on the Revolution of the Heavenly Spheres. In “On the Revolutions” (Rosen, Trans.) Baltimore: The Johns Hopkins University Press p 5, 1992. (For what Copernicus referenced see Lactantius, L. The Divine Institutes. In “Ante-Nicene Fathers” (Roberts & Donaldson, Eds.) Peabody, MA: Hendrickson Publishers, Inc. pp 94-95, 1999.)

7. Ibid, p 3.

8. Thoren VI: “The Lord of Uraniborg.” New York, Cambridge University Press, pp 277-279, 1990.

9. Kepler would publish his third planetary law in 1619.

10. de Santillana G: “The Crime of Galileo.” New York: Time, Inc., p 112, footnote #29, 1955/1962.

11. Casper M: “Kepler.” (Hellman, Trans.) New York: Abelard-Schuman, p 137, 1959.

12. Kepler J: “New Astronomy.” (Donahue, Trans.) New York: Cambridge University Press, p 60, 1992.

13. Ibid, p 61.

14. Ibid, p 62.

15. Ibid, p 63.

16. Ibid, p 63.

17. Galileo G: Reply to Ingoli (1624) In “The Galileo Affair – A Documentary History.” (Finocchario, Trans.) Berkeley: The University of California Press, p 156, 1989.

18. If this is so, I find it interesting that Galileo would ignore the scientific findings of Brahe and Kepler because he thought they were not Christians. Kepler had a conventional marriage, but both Brahe and Galileo were attracted to women who were beneath them socially. Brahe, a nobleman, married a commoner and then fought to have his children recognized as high born. On the other hand, Galileo did not marry the woman he was attracted to, but later fought to have his son declared legitimate. His illegitimate daughters he put in a convent. So just who was living the better Christian life? The last irony is that Galileo himself will be branded a suspected heretic.

19. Panofsky E: “Galileo as a Critic of the Arts.” The Hague: Nijhoff, pp 24-25, 1954.

20. Sobel D: “Galileo’s Daughter.” New York: Walker & Co., p 73, 1999.

21. Ibid, p 29.

22. One was in a 12 January 1615 letter from Prince Cesi, founder and head of the Lincean Academy and another in a 7 March 1615 letter from Monsignor Piero Dini. In The Galileo Affair, pp 300-301.

23. Galileo’s Daughter, p 73.

24. The Galileo Affair, p 29.

25. Langford JJ: “Galileo, Science and the Church.” Ann Arbor: The University of Michigan Press, p 81, 1971.

26. Galilei G: The Assayer. In Galileo Heretic, p 41.

27. Ibid, p 47.

28. Galileo’s Daughter, p 8.

29. The Galileo Affair, p 32.

30. Ibid, pp 303-304.

31. Campanella T: Defense of Galileo. In “Gateway to the Great Books, Vol. 8” (Hutchinson and Adler, Eds.) Chicago: Encyclopedia Britannica, Inc., pp 361-364, 1963.

32. Wallace WA: “Reinterpreting Galileo.” Washington, D.C.: The Catholic University of America Press, p 27, 1986.

33. Galilei G: Letters on Sunspots In “Discoveries and Opinions of Galileo” (Drake, Trans.) Garden City, MY: Doubleday & Co., p 97, 1957.

34. Galilei G: Letter to Monsignor Dini, 23 March 1615. In The Galileo Affair, p 61.

35. Galileo’s Daughter, p 286.

36. Nooni G: “Saggi Galileiani: Atomi, immagini e ideologia.” Cagliari, Italy: AM&D Edizioni, 2000.

37. The Crime of Galileo, p 307.

38. Van Helden A: Galileo, telescopic astronomy, and the Copernical system. In “Planetary astronomy from the Renaissance to the rise of astrophysics, Part A: Tycho Brahe to Newton.” (Taton and Wilson, Eds.) New York: Cambridge University Press, pp 101-102, 1989. The insertion in the quotation is by Van Helden.

39. Wallace WA: “Galileo and His Sources.” New Jersey: Princeton University Press, p 311, 1984.

40. The Crime of Galileo, p 166.

41. Galileo Heretic, p 240.

42. Inchofer M: Document EE291. (Shea, Trans.) Graciously furnished in a letter from William Shea to the author, May 2002. (For clarity, the order of the quotations is reversed from that in Document EE291.)

43. The Galileo Affair, pp 229-232.

44. Galilei G: Letter to the Grand Duchess Christina (1615). In Discoveries and Opinions of Galileo, p 186.

45. Hummel CE: “The Galileo Connection.” Downers Grove, IL: InterVarsity Press, p 23, 1986.

46. Blackwell RJ: “Galileo, Bellarmine, and the Bible.” London: University of Notre Dame Press, p 183, 1991.

47. Galileo Heretic, p 259.

48. This “lessor-charge” approach is nothing new. Less than a decade earlier, Archbishop Marco De Dominis, who was known for heresies concerning the pope, councils, and the Eucharist, was condemned for a manuscript on divorce in the case of adultery. Ibid, p 117.

49. Galileo’s Second Deposition (20 April 1633). In The Galileo Affair, p 278.

Emerson Thomas McMullen Department of History Georgia Southern University Statesboro, GA 30460

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