Popular Science Monthly/Volume 67/May 1905/Galileo III

by Edward Singleton Holden

Layout 4

GALILEO.

By EDWARD S. HOLDEN, Sc.D., LL.D.,

U. S. MILITARY ACADEMY.

III.^[1]

AN extant annotation dated February 26, 1616, which is undoubtedly genuine, declares that upon this day Galileo was summoned before Cardinal Bellarmine and in the presence of witnesses was warned of the error of the Copernican opinion taught by him, and was admonished henceforth not to hold, teach or defend it in any way whatsoever, verbally or in writing . . . which injunction the said Galileo promised to obey. The exact wording should be noticed. Upon it the subsequent fate of Galileo hangs. The document is genuine. Does it represent the facts of his examination of 1616 exactly as they occurred?

The proceedings against Galileo in 1632-3 show that the Pope and the Holy Office acted precisely as if the statements of the annotation were exact. The publication of his Dialogues (1631) was a flagrant violation of the command not to teach, etc. In the case of a personage so celebrated as Galileo nothing less than a flagrant violation would be noticed. The Roman Curia could not afford to harass him about trifles. With his defense of 1633 he submitted the following certificate:

We, Roberto Cardinal Bellarmine, having heard that it is calumniously reported that Signor Galileo Galilei has in our hand abjured and has also been punished with salutary penance, and being requested to state the truth as to this, declare: that the said Signor Galileo has not abjured . . . any opinion or doctrine held by him,^[2] neither has any salutary penance been imposed upon him; but only the declaration made by the Holy Father and published by the Sacred Congregation of the Index has been intimated to him, wherein it is set forth that the doctrine attributed to Copernicus, . . . is contrary to the Holy Scriptures and therefore can not be defended or held.^[3] In witness whereof we have written and subscribed these presents with our hand this 26th day of May, 1616. Roberto Card. Bellarmino.

Galileo's enemies had spread the calumnious reports mentioned. He wished to have a proof that they were false. Cardinal Bellarmine was his friend and admirer and at his request gave this certificate. Bellarmine died in 1621 and could not be called as a witness in 1632. When Galileo was called upon to defend himself for teaching the Copernican doctrine in his Dialogues, which had given great offense, he produced this certificate and called attention to its wording, which differs materially from that of the protocol of February 26, being much less stringent in form. In essence it is the same; to teach a doctrine as true is to 'defend' it. Cardinal Bellarmine did not have the protocol before him in writing the informal certificate. The prohibition of the latter is, however, precise and absolute; the doctrine 'can not be defended,' that is, taught in any way as if it were true. It can not even be 'held,' silently. It represented the attitude of the cardinal's mind precisely; the church would not suffer if its terms were obeyed. In reading Galileo's defense of 1632-3, we shall see the use he made of the discrepancy between these two documents, one formal and of record (February 26), the other friendly and informal (May 26).

It is the theory of Gebler in his careful history, 'Galileo Galilei and the Roman Curia,' that the genuine document of February 26 is not a true record of the facts. He admits that it was written in its proper place by the notary. He finds an 'obvious contradiction' between a formal command 'not in any way to hold or defend,' which are the words of the process of 1633, and the prohibition of Bellarmine's certificate 'not to defend or hold.' After an examination of all the documents it is impossible, I think, to take Gebler's view. It is necessary to admit the words of the genuine documents to mean precisely what they say.

Gebler lays down three facts as indisputable: '(I.) Galileo did not receive any prohibition except the cardinal's admonition not to defend or hold the Copernican doctrine; (II.) Entire silence on the subject was therefore not enjoined upon him; (III.) The second part of the note in the Vatican MS. of February 26, 1616, is therefore untrue.' My own conclusions are entirely different as to all three prohibitions. The Cardinal's admonitions are, in effect, absolutely the same as those of the formal prohibition; silence was enjoined, and more than this Galileo was forbidden to hold certain opinions even mentally and silently. If not, what does Bellarmine mean by the word 'hold'? Is it, I ask, credible that an authority that forbids a man to hold an opinion, even silently, would permit him to teach it? To ask the question is to answer it. When Galileo taught the opinion he disobeyed the orders of a Church whose authority he fully admitted during the whole of his life.

Within the assigned limits of this paper the matter can not be discussed at length. Two points may be touched upon however. Galileo's letters to Florence in 1616 do not mention the prohibition to himself for two good reasons, first, to divulge the proceedings of the Holy Office would have been a serious matter; second, Galileo had every reason for convincing his friends that the Holy Office had only come to decisions 'purely public' regarding the Copernican doctrine, and 'not affecting my [his] personal interests' (letter of March 6, 1616).

Again, the protocol of February 25 gives the orders of the Pope that certain things should be done 'in case of his refusal to obey.' It does not explicitly enjoin or prohibit the same action after his promise of obedience. Cardinal Bellarmine had full power in such a matter. If Galileo had refused to obey he would have been imprisoned. When he had promised to abandon the opinion of Copernicus the obvious step for Cardinal Bellarmine was to bind him to effective silence by a formal promise before witnesses. The protocol of February 26 recites that this was done. The words mean, I am obliged to conclude, precisely what they say. It must not be forgotten that Galileo, like every other good Catholic, had been forbidden to hold the Copernican opinion by the general prohibition of March 5, 1616.

The reigning Pope was Paul V., who hated 'science and polite scholars.' He was very civil to Galileo, however, received him graciously (March 11, 1616) and promised him safety from his enemies. Galileo was a celebrity; by his submission to authority he had averted a great scandal in the church; accordingly the Pope was gracious. For the next seven years (1616-23) Galileo's conduct precisely agrees with the supposition that he recognized that he must not teach the Copernican doctrines. He published nothing during this period. The authorities at Rome were engaged in 'correcting' the work of Copernicus. Galileo eagerly waited for the corrections, for they would be authoritative and would exhibit the limits within which it would be permitted to 'teach.'

In May, 1618, he sent a MS. copy of his treatise on the tides to Archduke Leopold of Austria, who was friendly to him. It implicitly assumes the truth of the Copernican doctrine "which I then (1616) held to be true^[4] until it pleased those gentlemen to prohibit the work and to declare that opinion (of Copernicus) to be false and contrary to Scripture. Now, knowing as I do, that it behoves us to obey the decisions of the authorities, and to believe them, since they are guided by a higher insight than any to which my humble mind can attain, I consider this treatise which I send you merely to be a poetical conceit, or a dream, and desire that your Highness may take it as such . . . ." The words are ironical. They will have less effect upon us when we remember that the science of this treatise of Galileo's is quite erroneous. It denies that the moon controls the tides. The treatise was not published. It was shown in MS. to a few trusted friends, but the ideas here set forth were developed in Galileo's Dialogues published in 1632.

In 1618 three comets appeared in the sky. Galileo communicated his views of their nature to a few friends. He considered them to be merely atmospheric appearances which rise far beyond the moon, to be sure, and not heavenly bodies. The conclusion was erroneous, of course. In 1619 the Jesuit Father Grassi delivered a lecture in Rome maintaining that the comets were heavenly bodies (as they are). Galileo induced one of his pupils to reply to Grassi, and himself corrected the MS. work so that its severe criticisms of the Jesuit (who was, after all, defending a true thesis) are Galileo's own. A reply was written by Grassi in which Galileo is personally attacked and the Copernican system assailed. Galileo's answer is the famous Il Saggiatore (the assayer) which was printed October, 1623. It was brilliantly, but very carefully written, and before it was published it passed from hand to hand among Galileo's friends, who purged it of every phrase likely to be dangerous. The imprimatur was given on a report of Father Riccardi,^[5] a former pupil of Galileo's, of whom we shall hear more.

In July Pope Gregory XV. died and was succeeded by Urban VIII. who, as Cardinal Maffeo Barberini, had for many years been one of Galileo's strongest supporters. A new era seemed to open with his accession. His many letters to Galileo had always been friendly, often cordial. In thanking Galileo for his letters on solar spots (1613) the cardinal had written: "I shall not fail to read them with pleasure, again and again, which they deserve. . . . I thank you very much for your remembrance of me, and beg you not to forget the high opinion that I entertain for a mind so extraordinarily gifted as yours." In 1620 the cardinal composed a poem in Galileo's honor and sent it to him as a 'proof of great affection.'

During the progress of Galileo's affair with the Holy Office in 1615 and 1616, the cardinal stood his friend and believed that it was chiefly to his own efforts that an issue so satisfactory to the astronomer personally was brought about. He was a friend to Galileo; he was not a believer in the Copernican doctrine; he made no efforts to prevent its condemnation. He proved to be inexorable where the interests of the papacy were, or seemed to be, involved. His accession was hailed by Galileo's friends, and Il Saggiatore was dedicated to him, and he accepted the dedication. The book is considered a model of dialectic skill and a literary masterpiece. The original controversy about the comets is almost lost sight of. The errors of Grassi are shown up mercilessly. The Copernican system, which Galileo ‘as a pious Catholic considers entirely erroneous and completely denies’ is covertly defended. It is shown to agree with the revelations of the telescope; and these are proved to be inexplicable on any other system. As the Copernican opinion is, however, condemned by the church, as Ptolemy's is untenable, and Tycho's inadequate, Galileo concludes that some other system must be sought for.

In this brilliant essay—which was withheld until Galileo's powerful friend was seated in the pontifical chair—Galileo held, taught and defended the Copernican doctrine. It was supposed to be, at least, safe for him to do so in a covert way. The book was read by the Pope, who enjoyed it highly—so Galileo heard. It was examined by the Inquisition and no action was taken. By these and other signs Galileo judged that an attempt to remove the condemnation of the Copernican system might now, at least, succeed. Its weightiest opponent, Cardinal Bellarmine, an earnest, sincere and learned man, had died in 1621. Galileo proposed to go to Rome to congratulate the new Pope on his accession. The proposal was well received. Friends wrote to him: “I swear to you that nothing pleased his holiness so much as the mention of your name. . . the Pope replied that it would give him great pleasure, . . . if the journey would not be injurious to your health; for great men like you must spare themselves that they may live as long as possible.”

Galileo arrived in Rome towards the end of April, 1624. He was received with the greatest honor. Every one knew the Pope to be his friend and that he had many supporters among notabilities. In the space of six weeks he was granted six long audiences with the pontiff. The Copernican system was discussed. Galileo argued warmly in its favor. He met with no success, while the Pope replied with arguments of his own against it. The new doctrine was not to be tolerated. Certain of the cardinals, at Galileo's request, engaged in the matter. The Pope was inexorable. No one can decide now what the Pope's arguments were. From the whole course of events, it seems probable that he was not satisfied that the Copernican theory was true; and it is evident that his mind was made up to allow no scandal to arise from its teaching. Galileo returned home loaded with favors. A pension was promised to his son. The Pope gave him a splendid picture, and two medals, and furthermore addressed a letter to the Grand Duke of Tuscany (June 7, 1624) in which he declares that Galileo's great discoveries ‘will shine on earth so long as Jupiter and his satellites shine in heaven.’ ‘That you may fully understand to what extent he is dear to us, we wish to give this brilliant testimony to his virtues and piety.’ ‘We have observed in him not only literary distinction, but also the love of religion and all the good qualities worthy of the papal favor.’

Galileo was again at the very summit of prosperity. He thought it safe, on his return to Florence, to write a reply to an Italian advocate, Ingoli, in which he defends the Copernican theory. In the first place he shows that he formerly defended it because of its inherent probability. He proves that he had not defended an idea improbable or unreasonable in itself. Again he desires to show the Protestant Copernicans in Germany that the heliocentric doctrine had not been rejected in Italy from ignorance of its great probability, but from reverence for Holy Scripture, zeal for religion and our holy faith.

Il Saggiatore had been well received. Why might he not go further under the favor of the Pope? All reports from Rome were favorable. And indeed he had heard (December, 1625) that the Pope had listened to several passages from this last pamphlet and had highly approved them. If he had gone so far, why then might he not go still farther? On the surface of affairs there was no apparent reason. Up to this time Galileo had preserved the forms fully. He professed not to hold Copernican doctrines. Not holding them, how could his writings be taken as teaching or defending them? The Pope, his friend, had not disapproved his previous writings. Galileo misinterpreted this as a sign of his toleration of the doctrines. It is now apparent that the Pope's whole course was consistent. He desired to give Galileo every liberty, but was sternly set against any teachings that would diminish the authority of the Church. From first to last he was unconvinced of the scientific truth of the Copernican opinion. He had personally befriended and honored Galileo. He looked for a grateful acknowledgment in return. Galileo had been denounced by his enemies, but they were overawed, and would certainly take up no quarrel in which he was not flagrantly disobedient to the prohibition of 1616. Il Saggiatore had been a brilliant success. He now set about arranging another work—the Dialogues on the two principal systems of the World—parts of which had been in hand for some years.

This is the place to record Galileo's share in the invention of the microscope. While he was in Rome (1624) a complicated microscope was shown to him that had been invented by Drebbel, a Dutchman. Galileo simplified and greatly improved it. His relation to the invention of the telescope and of the microscope is the same. The first ideas came from others; Galileo put them into practical forms. The real inventor of the microscope is not Drebbel, but Zacharias Jansen, a spectacle maker of Middleburg who made the first instruments in the last years of the sixteenth century, before the telescope was invented, therefore.

Galileo's dialogues on the system of the world (1632) have, at the head, a Greek epigraph:

 

In Every Judgment beware of Your Prejudices!

They are dedicated to the Grand Duke of Tuscany. The personages of the Dialogues are Salviati (Galileo himself) who maintains the Copernican doctrines; Sangredo, a man-of-the-world, intelligent, but not a savant; and Simplicius, a convinced Aristotelian, a dull fellow, always worsted in the argument. Galileo's enemies convinced the Pope that Simplicius stood for the Pontiff himself. The subjects discussed are the fall of bodies, the flight of projectiles, the principles of mechanics, the rotation and revolution of the earth and of the planets, the system of Ptolemy—and here Sangredo remarks that he knows many disciples of Ptolemy who have become Copernicans, but not one Copernican converted to the ancient system. The new star of 1572 is shown to have been far more distant than the moon, by long calculations (and it is noteworthy that logarithms are not employed to shorten the work). The preface recites that, some years previously a ‘salutary edict’ had been promulgated at Rome which, to prevent scandals, forbade the teaching of the Pythagorean opinion of the earth's motion,^[6] that some hardy spirits had, nevertheless, dared to declare that this edict had been issued without comprehension of the matter and that it was the result of passion, and not of judicial examination. It had been said that advisers entirely ignorant of astronomy ought not to have thus clipped the wings of philosophers.

My zeal, says Galileo, can not support these rash complaints. Well understanding this prudent decree, I wish to do justice to the truth. I was then at Rome; the most distinguished prelates heard and applauded me; the decree would not have been issued without giving me some knowledge of it. I, therefore, wish to show to foreign nations that in Italy, and even at Rome, all that could be advanced in favor of Copernicus was known, before that censure was published. I declared myself the advocate of Copernicus. Proceeding according to a mathematical hypothesis, I endeavored to prove it to be preferable to that which declares the earth at rest, not in an absolute manner preferable, but in the sense in which it is attacked by pretended Aristotelians, who in their philosophizing neglect observations. He will show, he says, certain advantages of the heliocentric system. If Italians have not assented to the mathematical opinion of the motion of the earth, it is not because all of them have been ignorant of the reasons others allege in its support, but because they have other reasons based on piety, religion, on a knowledge of divine omnipotence and the weakness of the human understanding. It is the opinion of good authorities that the foregoing introduction was first written by Galileo, then revised by the censor at Rome—perhaps by the Pope himself—and finally returned to the author with permission to make such verbal changes as would not alter the sense of the Roman revision.

In the Dialogues the three interlocutors proceed to construct a scheme of the universe, step by step. The construction is made by Simplicius, and the system proposed by Copernicus and demonstrated by Galileo emerges triumphant. All the glory is for Copernicus and his advocate, Galileo. No credit is assigned to Kepler for his discoveries which had done away with the whole apparatus of epicycles retained by Copernicus. Kepler is not mentioned here or elsewhere with praise. Simplicius objects to some mathematical reasoning because Aristotle recommended his disciples to abstain from geometry. Salviati thinks Aristotle wise; for geometry is the art by which his errors and deceits are discovered. As to the empty spaces beyond Saturn: who are we to judge of the greatness of the universe? Can we say that these spaces are useless because we see no planet there? May they not be peopled with invisible planets? Who suspected the existence of the moons of Jupiter? Who tells us that all the heavenly bodies were created for us? Certain authors—Kepler, for one—assert that tides are caused by the moon. Galileo will not waste his time in refuting such assertions. Nothing is so astonishing to Galileo as that Kepler, a free and penetrating spirit, should have assented to such 'ineptitudes.' Simplicius on his part declares that the tides are miracles. In all the book there is no discussion of Scriptural texts.

It is not necessary to carry the analysis of these famous dialogues further. The arguments employed are so familiar to us that we forget they were once fresh and novel. They were accepted by Galileo's contemporaries as witty and brilliant, and even now Italians admire their style, though most English readers find them, as a whole, prolix, not to say dull. The Copernican doctrine is enforced in every possible way. Every argument for the Aristotelian theory is brought forward, in turn, by Simplicius only to be utterly refuted. Sarcasm is unsparingly employed. Simplicius is not only wrong, but ludicrously so. After each unusually convincing passage Salviati is careful to add that, after all, the Copernican doctrine is a 'fantasy' or a 'vain chimera.' At the termination of the dialogues, which extend over four days, no general summing-up is made. The reader is left to draw his own conclusions. Salviati apologizes to Simplicius for the ardor of his language and assures him that he had no intention to offend him, but wished rather to stimulate him to communicate his 'sublime' ideas—ideas which have been utterly refuted in the course of the book. 'Your reasons,' says Simplicius, 'are most ingenious; but I do not believe them to be either true or conclusive.' Then Simplicius recalls a wise reflection, made formerly, in his presence, by an eminent personage before whom all must bow, as follows: 'We observe,' he says, 'nothing but appearances; by what right do you presume to limit the power of God by fixing the ways in which it has pleased Him to produce them?' These are the very words spoken by Pope Urban to Galileo in 1624. They were considered conclusive by the Pope. In the mouth of Simplicius they ring hollow.

It must not be forgotten that Galileo's theory of the tides upon which the Dialogues turn is, in itself, entirely erroneous. The tides are not due to the moon, he says, but to certain motions of the earth, which are then discussed. The first motion is its rotation round an axis, the second its motion of revolution about the sun, and there is a third motion by virtue of which its axis of rotation is constrained to pass always through the same stars. The third motion (invented by Copernicus) is superfluous. The axis of the earth is always parallel to itself as it moves round the sun. Two motions are sufficient to account for all the phenomena; the third does not exist. It was, however, upon this third motion that Galileo founded his theory of the tides, which is, therefore, baseless. Many of his arguments for the Copernican doctrine are irresistible. Those founded on the tides are, necessarily, erroneous.

To obtain the authority to print the Dialogues Galileo went to Rome (May, 1630), where his friend and former pupil, Father Riccardi, was censor (master of the Sacred Palace). Without the imprimatur nothing could be printed. When the imprimatur of the censor was once given to any book its author was prima facie relieved from responsibility. In the subsequent proceedings against Galileo it was charged that he obtained the imprimatur by a 'ruse.' The history, as understood at Rome, was briefly as follows: In May, 1630, Galileo took the MS. to Rome, submitted it to the master of the Sacred Palace (Riccardi) and asked permission to print. Riccardi wished, for greater security, to review the book himself. To save time, it was agreed that the book should be printed at once and that the sheets, leaf by leaf, should be sent to Riccardi. To carry out this plan the imprimatur was given for Rome. Galileo soon went to Florence and from thence asked the censor for permission to print at Florence. This permission was refused. Riccardi insisted that the sheets should be submitted to him according to the original agreement. The plague was then raging throughout Italy and it was impossible to transmit parcels from Florence to Rome on account of the quarantine.

It was finally arranged through the Tuscan ambassador, Niccolini, that the printing should be done at Florence under the condition of the submission of the whole work to a competent theologian of the Benedictine order, and that the introduction and conclusion should be sent, before issue, to the censor at Rome. The whole matter was then transferred to the inquisitor at Florence and the book was printed with the entire approval of Father Stephani, who had been charged with its supervision. The introduction and conclusion were duly sent to Rome, but the Roman censor kept them for months without giving his approval or, in fact, without communicating with Galileo. It was clear that Riccardi was doubtful. Through the Tuscan ambassador at Rome renewed efforts were made by Galileo to obtain Riccardi's approval, and, in the meantime, without waiting for it (March 1631) the printing was proceeded with at Florence. Riccardi (April 28, 1631) at last answered Galileo's request, refusing the imprimatur until new conditions had been fulfilled. The censor, in this letter, recalled the fact that this original imprimatur was only given conditionally.

“Father Stephani,” says the censor, “has no doubt subjected the book to a conscientious revision; but as he was not acquainted with the Pope's views he had no power to give any approval, etc.” A desire to delay the whole matter is evident. Riccardi fears for himself; he knows the Pope's views; he is a firm friend of Galileo's also. After further negotiations (May, 1631) the whole matter was referred to the inquisitor at Florence with full powers. Riccardi conveyed to the inquisitor the ‘views’ that must govern his decision: The Copernican system must be treated only as a mathematical hypothesis; there must be no reference to Scripture; the introduction and the conclusion of the book the censor will send from Rome. Accordingly, they were sent with permission to Galileo to change the rhetorical style but not the matter. It is the opinion of certain good authorities that the Pope himself revised the introduction. The book was finally printed (February, 1632) with the imprimatur of Rome and also of Florence. The authorities at Rome had not seen the text of the Dialogues. It appears that throughout the long and vexatious delays Galileo obeyed all explicit instructions given by the censors. There were good reasons for removing the printing of the work to Florence. It is, however, certain that it would never have been authorized in Rome in its final shape.

(To be continued.)

1. Continued from the Popular Science Monthly for February, 1905.
2. According to the terms of this certificate Galileo never had ‘held’ the Copernican opinion—or at least he had never ‘abjured’ it. The annotation of February 26, 1616, commands him to ‘relinquish’ it.
3. The words respecting teaching are not here given, it is to be remarked.
4. In this letter Galileo declares that he 'held' the opinion till 1616. He then 'relinquished' it (February 26), but never 'abjured' it (May 26).
5. Riccardi had been convinced that the Ptolemaic theory was false and had accepted in its place not the theory of Copernicus, but that of Tycho Brahe.
6. This general edict, of course, included Galileo, whether there was any special command laid upon him or no.