What exactly was said during those six audiences is not known. But a few points has been established:
(1) Urban refused to revoke the decree of 1616 in spite of Galileo's attempts at persuasion.These instructions were confirmed in writing by the head censor, Monsignor Riccardi. This suggestion of Urban's, of which he was very confident, played a crucial part in what follows.
(2) Galileo could write pretty well anything he pleased in support of Copernicus, so long as he avoided theological arguments, and spoke ex hypothesi.
(3) Urban himself made a suggestion how to get around the difficulty of arguing in favor of Copernican system without asserting it to be true. The suggestion was this: assuming that a hypothesis explained satisfactorily certain phenomena, this does not necessarily mean that it is true, for God is all-powerful and may have produced the said phenomena by some entirely different means which is not understood by the human mind; we must not restrict His omnipotence by the limits of human understanding.
Being greatly encourage by the papal favor, Galileo, who was pass
sixty, felt that he was free to start his great apology for Copernicus,
which he intended to call Dialogue on the Flux and Reflux of
the Tides. It took him four years to write it; for nearly
three years from 1626 to 1629 he laid it aside, for various reasons.
Maybe he had doubts about the soundness of his "conclusive
proof", his theory of tides. Any way he completed it in January, 1630.
The Dialogue has three characters or "speakers":
Salviatti, the brilliant savant, who presents the views of Galileo;
Sagredo, an intelligent amateur, who is neutral but is willing
and eager to learn; and
Simplicio, the good-nature simpleton, who is the defender of Aristotle
and Ptolemy.
Salviatti and Sagredo had been friends of Galileo, and were now both dead.
Simplicio, according to Galileo, drived his name from Simplicius, the sixth
century commentator on Aristotle, but the double meaning is obvious.
It is Simplicio who, over and over again is shown up as a fool,
at the end of the Dialogue sets forth Pope Urban's argument
as coming "from a most eminent and learned person, and before
whom one must fall silent": whereupon the other two declare
themselves silenced by "this admirable and angelic doctrine",
and decide "to go and enjoy an hour of refreshment in the
gondola that awaits us". And so the Dialogue ends
with what can only be described as a rude noise at the Pope.
The Dialogue is divided into four days. The first day is devoted to refutation of the Aristotelian view of the cosmos in general. On the second day, the battle for and against Copernicus is really joined. The objections against the earth's motion are refuted in terms of terrestrial physics. The classic objection to the motion of the earth are a variation on the following theme: that if the earth rotated, everything not firmly attached to the earth would left behind. In his answer to this objection Galileo comes close to the correct view of inertia and to Newton's First Law. He argues that if a stone is dropped from the top of a moving ship's mast, it would not be left behind because the stone shares the ship's inertia. By analogy that a stone dropped from the top of a tower would not be left behind. But Galileo is not able to break away from the Aristotelian concept of circular motion. He assumes that if a body is left to itself, it will continue to move, under its own inertia, not in a straight line, but in a circular orbit for eternity. His reason for this conclusion is that motion in a straight line is infinite (since a straight line is infinite and indeterminate) it is impossible. Galileo says, "For nature, as Aristotle says, never undertakes to do that which can not be done, nor endeavors to move wither it is impossible to arrive." Galileo can just rid him of the Aristotelian concept that natural motion is circular since it is the only form of motion that is infinite and can arrive at a place, the place from which it started. For Aristotle, and therefore for Galileo, all motion is teleological; it has an end (telos) toward which it moves, its final place or destination. The second day ends, on Galileo's admission, in a stalemate. He has refuted the objections against a rotating earth, but he has not proved that the earth rotates. On the third day Galileo is concerned with astronomical arguments for and against Copernicus. First he proves that the Copernican system is superior to the Ptolemaic system from the moons of Jupiter and the phases of Venus. He argues that Copernicus can explain the retrograde motion of the planets without the use of epicycles that Ptolemy had introduced for that purpose. But he does not mention that the Copernican system also had epicycles and epicentrics to account for the discrepancies for which the circular and uniform motion could not account. This is misleading and a distortion of the facts. He makes it appear that the Copernican system solves all the problems and "saves the phenomena". But even so Galileo has not proven that the Copernican system is true. Moreover, he has kept silent that the Tyconic system also saves the phenomena. To remedy this situation, on the fourth day, Galileo brings forth his great proof: his theory of the tides. But before he does that in book four, at the end of book three, he makes a new and unexpected argument from the motion of the sunspots. After reasserting his spurious claim to the discovery of sunspots, he proceeds to claim another discovery of Scheimer's: that the sun, and its sunspots, rotate about an axis that is tilted with respect to plane of the ecliptic. As a result of this, the spots also travel around the sun in "titled" circles (as seen from the earth); and their curves changes according to the earth's position. Therefore, Galileo concludes, the changing curves along which the spots travel, proves that the earth travels around the sun. At this point Simplicio correctly observes that the curve of the spots would be the same whether the sun traveled around the earth or the earth around the sun. Salviati proceeds to demolish this argument: if we assume that the sun travels around the earth, the spots will look the same only if we assume that the sun's axis always remain parallel with itself; and this he finds "very hard and almost possible to believe". Simplicio, intimidated, does not reply. Salviati is wrong; it is not impossible. But assuming it is impossible the following argument is obscure and is the most incomprehensible section of the book. The fourth and last day of the Dialogue entirely deals with the theory of tides, which it presents with more detail. The annual variation in the tides are explained by the tilt of earth's axis, the monthly variations by monthly changes in orbital speed. Kepler's explanation of tides by the moon's attraction is rejected and dismissed with ridicule.
The manuscript was finished in January, 1630. Galileo intended to supervise the printing of the book in Rome, but could not go at once. He arrived in Rome at the beginning of May and had a long audience with Pope Urban VIII. Again the Pope confirmed that there was no objection against discussing the merits of the Copernican system, provided that it was treated strictly as a hypothesis. He objected to the intended title, which laid too much emphasis on physical proof, and suggested that it should be titled instead Dialogue on the Great World Systems. He said he was too busy to read the book himself, and he would leave it to the censors. The function of Chief Censor and Licenser was exercised by the "Master of the Palace", Father Niccolo Riccardi. He was another Florentine, another member of the Castelli-Ciampoli clique, and devoted to Galileo, although he believed that the Ptolemaic and the Copernican systems were highbrow pastimes, since the stars are really moved by the angels. He read the manuscript of the Dialogue and concluded that it was way over his head. He knew what His Holiness had approved of the idea of the book, had showered favors on Galileo, and encouraged him to go ahead. But he sensed, although he could not follow the argument in detail, that the book was a thinly disguised propaganda for Copernicus, and was contrary to the spirit and letter of the decree of 1616. To escape this dilemma he instructed his assistant, Father Visconti, to work through the text and make suitable alterations. Visconti made some minor changes to make it appear to be "hypothetical", then handed it back to his superior. Riccardi tried to delay but he finally decided that he had to revise the text himself. But Galileo's allies brought pressure on him and he decided on a compromise; to save time, he would grant the imprimatur for the book in advance, on the condition that he would do the revision himself and then pass each revised sheet on to the printer. As soon as the agreement was concluded, Galileo left Rome for Florence. A plague broke out in Rome and the strict quarantine made communications between Rome and Florence difficult. This provided an excellent opportunity for Galileo to wiggle out of the conditions of the imprimatur that was granted; he demanded that the book be printed in Florence. Father Riccardi at first flatly refused to grant permission to print the book in Florence without revising it; he demanded that the manuscript be sent to Rome for revising. Galileo replied that the quarantine made it unsafe to send it to Rome and asked that the final revision be done by a Florentine censor. Galileo again had his allies apply pressure. Finally Father Riccardi relented that the work could be revised and printed in Florence, except for the preface and concluding paragraphs which must be submitted to him. The revision was to be done by the Florentine Inquistor, Father Clemente Egidii, but that was not agreeable to Galileo, who proposed that Father Stefani instead of Egidii. Again Riccardi agreed. Stefani made a few corrections and the printing began early in 1631. Riccardi must have been still disturbed about the book and tried to hold up the preface and the concluding paragraphs. Again pressure was brought to bear, and the first copies of the Dialogue came from the press in February, 1632.
The proceedings against Galileo began with the appointment of a special commission to investigate the whole affair. The Commission found
(1) that Galileo had transgressed orders in deviating from the hypothetical treatment of Copernicus, in maintaining absolutely the motion of the earth;This third point of the Commission refers to the entry in the Inquisition file dated Thursday, February 25, 1616, which the Commission found. The Commission did not recommend any specific action against Galileo; as for his book, the contents were indicted on eight points, but the Commission suggested that all these matters could be corrected in the book. The Commission's report was given to the Inquisition for further action, and the Inquisition issued a summons in October, 1632, and first interrogated Galileo on April 12, 1633. According to the basic rule of the Inquisitorial procedure, the charges were not communicated to the accused; in stead the accused was asked whether he knew or could guess on what grounds he had been summoned. Galileo said that he believed it was on account of his latest book. Then the Commissary, Firenzuola, then questioned him in detail about the event of 1616. Galileo stated that he had been told by the Lord Cardinal Bellarmine that "the opinion of Copernicus, if adopted absolutely, was contrary to Holy Scripture and must neither be held nor defended, but that it could be taken and used hypothetically." He also affirmed that he had "not in any way disobeyed this command, that is, had not by any means held or defended the said opinion." The Inquisitor then read to him the absolute injunction of 1616 that Galileo must "neither hold, defend, nor teach that opinion in any way whatsoever". Galileo did not directly deny hearing the absolute injunction, but said he could not remember the words "not to teach" and "in any way"; then he referred to Bellarmine's certificate that it did not contain the words of the absolute injunction. Then the Inquisitor went over the whole story of the negotiations concerning the imprimatur. He asked whether when Galileo applied for permission to print the Dialogue, did Galileo inform Father Riccardi about the command that had been issued to him. Galileo answered that he did not think it necessary to do so, "for I have neither maintained nor defended in that book the opinion that the earth moves and that the sun is stationary, but have rather demonstrated the opposite of the Copernican opinion, and shown that the arguments of Copernicus are weak and not conclusive." With that the first hearing ended.
(2) that he had erroneously ascribed tides to the motion of the earth; and
(3) that he had been deceitfully silent about the command laid upon him by the Holy Office in 1616 "to relinquish altogether the said opinion ... nor henceforth to hold, teach or defend it in any way whatsoever, verbally or in writing."
Five days after the first hearing, three experts of the Inquisition, who had been appointed to examine the contents of the book, gave their report. They found that Galileo had not only not discussed the Copernican view as a hypothesis, but he had taught, defended and held it, and that he had called those who did not hold it "mental pygmies", "dumb idiots", and "hardly deserving to be called human beings". They defended their conclusions by a long list of quotations from the book.
Galileo then had several months to prepare his defense. To pretend that the Dialogue was written in refutation of Copernicus was so patently false, in light of the evidence from the printed pages of the book, that it would be suicide to defend himself this way. This was obvious to the Commissary of the Inquisition, Firenzuola, who requested permission from the Holy Congregation to interrogate Galileo off-the-record, "extra-judicially", to get a confession from him. Even though the Holy Congregation held little hope that it would work, they granted permission. In Father Firenzuola's words in his letter to Pope Urban's brother, Cardinal Francesco Barberini, on April 28, 1633,
"That no time would be lost, I entered into discourse with Galileo yesterday afternoon, and after many and many arguments and rejoinders had passed between us, by God's Grace, I attained my object, for I brought him to a full sense of his error, so that he clearly recognized that he had erred and had gone too far in his book. And to all this he gave expression in words of much feeling, like one who experienced great consolation in the recognition of his error, and he was also willing to confess it judicially. He requested, however, a little time in order to consider the form in which he might most fittingly make the confession, which, as far as its substance is concerned, will, I hope, follow in the manner indicated."Two days later on April 30, 1633 Galileo was called for examination a second time, ask if he anything to say. Galileo made a statement in which he confessed the errors in his book.
"I freely confess that in several places it seemed to me set forth in such a form that a reader ignorant of my real purpose might have had reason to suppose that the arguments on the false side, and which it was my intention to confute, were so expressed as to be calculated rather to compel conviction by their cogency than to be easy of solution."Near the end of his statement he says:
"My error, then, have been - and I confess it - one of vainglorious ambition and of pure ignorance and inadvertence."After he was dismissed, Galileo returned and volunteered a supplementary statement:
"And in confirmation of my assertion that I have not held and do not hold as true the opinion which has been condemned, of the motion of the Earth and stability of the Sun -- if there shall be granted to me, as I desire, means and time to make a clearer demonstration thereof, I am ready to do so..."He then offers to add two other "days" to his book, in which "I promise to resume the arguments already brought in favor of the said opinion, which is false and has been condemned, and to confute them in such most effectual manner as by the blessing of God may be supplied to me." When he finished the statement, the hearing was closed.
Ten days later, on May 10, 1633, Galileo was called again to a purely formal hearing, at which he gave them a written defense. In it he argued that he was unaware of a specific and absolute injunction in 1616, and he makes a convincing case for this. The remainder of the trial was expected to be a formality. Throughout the whole proceedings Galileo was treated with great consideration and courtesy. He was not confined to the dungeons of the Inquisition but was allowed to stay as the guest of Tuscan Ambassador, at the Villa Medici, until the first examination. Then he had to surrender formally to the Inquisition, but instead of being put into a cell, he was assigned a five-roomed flat in the Holy Office itself, overlooking St. Peter's and the Vatican gardens, with his own personal valet and the Tuscan Ambassador's major domo to look after his food and wine. He stayed there from April 12 to the third examination on June 21. Then, before his trial ended, he was allowed to return to the Tuscan Embassy. Contrary to legend Galileo never spend a day of his life in a prison cell.
Six weeks later on June 16, 1633, the Congregation decreed he must be sentenced. On June 20, 1633, Galileo was summoned for the third and last examination. After he had taken the oath, he was questioned about his real conviction concerning the two cosmological systems. He answered that before the decree of 1616 he had considered that either Ptolemy or Copernicus might be true in nature, "but after the said decision, assured of the wisdom of the authorities, I ceased to have any doubt; and I held, as I still hold, as most true and indisputable the opinion of Ptolemy, that is to say, the stability of the earth." Then Galileo was told that by the manner in which the subject was treated in the Dialogue, and the fact that he had written the said book, he was presumed to have held the Copernican opinion since the decree, and he was asked a second time to state the truth freely. He answered that he had written the book to confer a common benefit by setting forth arguments on both sides, and repeated again, "I do not now hold the condemned opinion, and have not held it since the decision of the authorities." He was admonished a third time that the contents of the book he was presumed to hold with Copernicus, or at least to have done so at the time he wrote it, and that therefore "unless he made up his mind to confess the truth, recourse would be had against him to the appropriate remedies of law." Galileo answered,
"I do not hold, and have not held, this opinion of Copernicus since the command was intimated to me that I must abandon it; for the rest I am here in your hands - do with me what you please."When he was for the last time bidden to speak the truth, Galileo repeated,
"I am here to obey and I have not held this opinion since the decision was pronounced, as I have stated."If the Inquisition intended to break Galileo, this was the time to confront him with the statements from his book. Instead, immediately following Galileo's last statement, the minutes of the trial say:
"And so nothing further could be done in execution of the decree, his signature was obtained to his disposition and he was sent back."Both the judges and the defendant knew he was lying; both the judges and he knew that the threat of torture was a ritual formula and could not be carried out; and they knew that the hearing was a formality.
Galileo was led back to his five-room apartment, and on the next day, June 21, 1633, the sentence was read aloud to him. It was signed by only seven of the ten judges. Among the three whom did not sign was Cardinal Francesco Barberini, Urban's brother. The Dialogue was prohibited; Galileo was to abjure the Copernican opinion, was to be sentenced to "formal prison during the Holy Office's pleasure"; and for three years to come, was to repeat once a week the seven penitential psalms. He was then presented with the formula of adjuration, which Galileo read aloud. That was the end of the trial.
He was officially convicted, according to the sentence read to him, of heresy; in the words of the sentence:
"We say, pronounce, sentence, and declare that you, the said Galileo, by reason of the matters adduced in trial, and by you confessed as above, have rendered yourself in the judgment of this Holy Office vehemently suspected of heresy, namely, of having believed and held the doctrine - which is false and contrary to the sacred and divine Scripture - that the Sun is the center of the world and does not move from east to west and the Earth moves and is not the center of the world; and that an opinion may be held and defended as probable after it has been declared and defined to be contrary to the Holy Scripture; and that consequently you have incurred all the censures and penalties imposed and promulgated in the sacred canons and the other constitutions, general and particular, against such delinquents."The sentence goes on to set forth the penalties:
"From which we are content that you be absolve, provided that, first, with a sincere heart and unfeigned faith, you adjure, curse, and detest before us the aforesaid errors and heresies and every other error and heresy contrary to the Catholic and Apostolic Roman Church in the form to be prescribed by us for you. And, in order that this your grave and pernicious error and transgression may not remain altogether unpunished and you may be more cautious in the future and an example to others that they may abstain from similar delinquencies, we ordain that the book of the 'Dialogue of Galileo Galilei' be prohibited by public edict. We condemn you to formal prison of this Holy Office during our pleasure, and by way of salutary penance we enjoin that for three years to come you repeat once a week the seven penitential Psalms. Reserving to ourselves liberty to moderate, commute, or take off, in whole or in part, the aforesaid penalties and penance."The formula of adjuration, that Galileo read aloud "with a sincere heart and unfeigned faith", said in part:
"But whereas - after an injunction has been judicially intimated to me by this Holy Office to the effect that I must altogether abandon the false opinion that the Sun is the center of the world and immovable and that the Earth is not the center of the world and moves and that I must not hold, defend, or teach in any way whatsoever, verbally or in writing, the said false doctrine, and after it had been notified to me that the said doctrine was contrary to Holy Scripture - I wrote and printed a book in which I discuss new doctrine already condemned and adduce arguments of great cogency in the favor without presenting any solution of these, I have been pronounced by the Holy Office to be vehemently suspected of heresy, that is to say, of having held and believed that the Sun is the center of the world and immovable and that the Earth is not the center and moves; Therefore, desiring to remove from the minds of your Eminencies, and of all faithful Christians, this vehement suspicion justly conceived against me, with sincere heart and unfeigned faith I adjure, curse, and detest the aforesaid errors and heresies and generally every other error, heresy, and sect whatsoever contrary to the Holy Church, and I swear that in future I will never again say or assert, verbally or in writing, anything that might furnish occasion for a similar suspicion regarding me; but, should I know any heretic or person suspected of heresy, I will denounce him to this Holy Office or to the Inquisitor or Ordinary of the place where I may be. Further, I swear and promise to fulfill and observe in their integrity all penances that have been, or that shall be, imposed upon me by this Holy Office... So help me God and these His Holy Gospels, which I touch with my hands."It is a myth that Galileo at this point kicked the ground and muttered under his breath, "Eppur si muove" ("But it does move.").
The heresy of which Galileo was accused and convicted, namely, the sun-centered universe, had never been officially declared a heresy, since neither the opinion of the Qualifiers, nor the decree of the Congregation of 1616, had been confirmed by infallible pronouncement ex cathedra or by Ecumenical Council. On the contrary, had not Pope Urban VIII himself said that the Copernican opinion "was not heretical but merely reckless"? Thus Galileo was convicted of an heresy that was not an heresy.
Although officially convicted, clearly Galileo got off without any punishment. As the Pope said to the Tuscan Ambassador, Niccolini, on June 18, two days after the sentence decision,
"However, after the publication of the sentence we shall see you again, and shall consult together so that he may suffer as little distress as possible, since matters cannot be let pass without some demonstration against his person."The Pope clearly intended to be lenient. However, it was the intent of the Inquisition that Galileo should spend a long period of penitence in the monastery of Santa Croce in Gerusalemme. However, Ascario Piccolomini, Archbishop of Siena, with the help of Cardinal Barberini, had Galileo committed to his care. So the "formal prison" took the form of a short sojourn at the Grand Duke's villa at Trinita del Monte, followed by a sojourn of five months at the archiepiscopal palace in Siena, where according to a French visitor, Galileo worked "in an apartment covered in silk and most richly furnished". Although the provision was imposed that Galileo was to see no one, the Archbishop opened the door to all who wanted to see him. After that it was intended that Galileo should be committed to the Charterhouse of Florence. This sentence was commuted and he was allowed to return to his farm at Arcetri, and later to his house in Florence, where he spent the rest of his life. The recital of the penitential Psalms was delegated, with the consent of religious authorities, to his daughter, Sister Marie Celeste, a Carmelite nun. It is apparent that it was not the intent of the Pope or the Holy Office to completely destroy Galileo; their intention was clearly to treat the famous scholar with consideration and even leniency, but at same time to stop his arrogance and to prove that even a Galileo would not be allowed to make fun of the Pope, the Holy Office, the Dominicans, and the Jesuits. "Galileo had a rare gift of provoking enmity, ...the cold, unrelenting hostility which genius plus arrogance minus humility creates among mediocrities." And he had made many enemies.
Shortly after the trial was over, a copy of the prohibited Dialogue was smuggled out to Kepler's old friend, physician Johannes Bernegger in Strasburg, who arranged for a Latin translation, which was published in 1635 and circulated widely in Europe. A year later, Bernegger arranged for Italian and Latin versions of the Letter to the Grand Duchess Christina to be published in Strasbourg. Galileo spent the year following the trial writing the book on which his true and immortal fame is based, the Dialogue concerning the Two New Sciences. In it he returns to the subject that he had abandoned a quarter century before for his ill fated propaganda crusade for the Copernican heliocentric astronomical system. In this book Galileo lays the foundation of modern mechanics. It contains the idea of inertia, the law of falling bodies, the principle of compound motion, and Galilean principle of relativity. The book was completed in 1636, when Galileo was seventy-two and a year before he went blind. Since he could not get the imprimatur for the book in Italy, the manuscript was smuggled out by the Dutch publisher, Elzevirs, who visited Italy in 1636, to be published in Holland, a Protestant country. It was published at Leyden in July, 1636, carrying a forward in which Galileo denied all knowledge as to how his manuscript might have fallen into Elzevirs' hand; the sentence imposed on Galileo had forbidden him of publishing any of his works.
After he lost his sight, Galileo continued to work on his Two New Sciences, dictating additional chapters. In 1639 the Pope flatly refused to release Galileo, now seventy-five and blind. On January 8, 1642, Galileo died at Arcetri, still under the ban of the Inquisition. The Pope forbade the Grand Duke of Tuscany to erect any monument to Galileo, lest any inscription on it would "offend the reputation of the Holy Office". Galileo's body was laid away in the basement of the bell tower of Santa Croce for nearly one hundred years. It now rests in the Pantheon of the Florentines, the Church of Santa Croce, next to the remains of Michelangelo and Machiavelli, with his epitaph that was written for him by posterity, "Eppur si muove" ("But it does move"), the famous words that Galileo is supposed, according to legend, to have said under his breath at the end of his adjuration.