The Essential Galileo (47 page)

32.
Cf. Aristotle,
Physics
, II, 14, 296b31–32. This was a basic principle of Aristotelian physics. Here it is applied to derive the existence of the Prime Mobile.

33.
Cf. Aristotle,
Physics
, VIII, 1, 251a10.

34.
Cf. Aristotle,
Physics
, I, 6, 189b17–29.

35.
Galilei 1890–1909, 7: 150.13–159.28; translated by Finocchiaro (1997, 142–55).

36.
Cf. Aristotle,
On the Heavens
, II, 14, 296a24–297a8. Galileo places quotation marks around the text of the next five paragraphs, thus suggesting that he is quoting from an edition of Aristotle; but the language of these quotations is Italian rather than Latin, indicating that they are his own translations. My translation is from Galileo's Italian text. I have closed the quotation marks in the middle of the statement of the third argument because the subsequent text makes it clear that what follows is paraphrase or indirect quotation.

37.
Cf. Ptolemy,
Almagest
, I, 4–7; Brahe (1596, 167, 188–89; 1602, 662).

38.
Wursteisen (1544–88), a German-Swiss astronomer and one of the first to be favorably disposed toward Copernicanism.

39.
Here (last four sentences) Galileo advances an important argument involving the greater open-mindedness of Copernicans vis-à-vis Ptolemaics.

This argument was held against him and generated one of the charges that led to the 1633 trial; see §9.1.2.6.vii. Galileo had elaborated the argument even more fully in his reply to Bellarmine; see §5.2.

40.
Cf. Aristotle's
Physics
, 192b21–24.

41.
The exchange between Sagredo and Simplicio of the last several paragraphs is an elaboration and refinement of a point briefly made by Galileo in his reply to Bellarmine; see §5.4.6. Galileo is making a plea for the value of critical reasoning, namely the ability to distinguish good from bad arguments; for more details, see Finocchiaro 1997, 142–55 nn. 57–89; 339–41.

42.
Galilei 1890–1909, 7: 164.30–175.23; translated by Finocchiaro (1997, 155–70).

43.
Cf. Aristotle,
Physics
, II, 14, 296b22–26.

44.
The resulting compound path would not be straight if (as indeed is the case) the downward fall is accelerated while the horizontal motion is uniform; thus, the actual path is parabolic, as Galileo proved in
Two New Sciences
. Cf. §10.8.

45.
Aristotle,
Meteorology
, I, 7, 344a11.

46.
Cf. Virgil,
Aeneid
, IV, 175, which refers to rumors and how they spread.

47.
The agreement here reached by Salviati and Simplicio embodies an important physical principle, which may be called the principle of the conservation of motion; it represents Galileo's approximation to two fundamental laws of classical physics—the law of inertia and the law of the conservation of momentum. Cf. Newton 1999, 416, and the principle of indifferent motion in §3.1.

48.
Galilei 1890–1909, 7: 346.25–368.31; translated by Finocchiaro (1997, 221–44).

49.
Johannes Locher,
Disquisitiones mathematicae de controversiis et novitatibus astronomicis
(Ingolstadt, 1614). This book is severely criticized in other parts of the
Dialogue
.

50.
Cf. Aristotle,
On the Heavens
, I, 5–7.

51.
This ellipsis is in Galileo's original text, for he wants to portray an interruption in Simplicio's speech caused by Salviati's next interjection.

52.
Quadrature
is a configuration of the apparent position of two heavenly bodies when they form a right angle with the earth, namely when they appear to be ninety degrees apart as seen from the earth; for example, a half moon is seen when the sun and moon are “in quadrature.”

53.
Sextile configuration
is a configuration of the apparent position of two heavenly bodies when they are sixty degrees apart as seen from the earth.

54.
In the original 1632 edition of the
Dialogue
, there is no indication of a gap or an addendum at this point in the text. But in his own copy of the book, at this point Galileo made a handwritten note stating that it would be a good idea to insert some text here, and at the end of the Day III he inserted several sheets of paper on which he wrote the text of the addendum. Favaro (1890–1909, 7: 356–62) prints this addendum in a note to the main text; Drake (1967, 328–33) inserts this additional text at this point, placing it in square brackets. I have omitted the addendum from my translation because the additional text has primarily rhetorical import but little scientific or philosophical significance. Finally, note that in the rest of this paragraph, the pagination of the critical edition shows a rapid succession of pages; this is because on each of these pages the addendum printed as a footnote takes up most of the space and there are only a few lines of the main text.

55.
Cf. Copernicus,
On the Revolutions
, I, 10 (1992, 18–22).

56.
This ellipsis is in the original; Galileo wants to represent an interruption of Salviati's speech by Simplicio.

57.
Elongation
is the angular distance (as seen from the earth) of one heavenly body from another.

58.
Galilei 1890–1909, 7: 445.22–462.15; translated by Finocchiaro (1997, 282–303).

59.
The tides have just been described briefly and presented as a fact to be explained; Salviati has proposed explaining them by the hypothesis that the earth moves.

60.
Marcantonio de Dominis (1566–1624), archbishop of the Dalmatian city of Split, who had published a book on the subject (
Euripus, seu de fluxu et refluxu maris sententia
, Rome, 1624).

61.
It was then well known that normally there are two high and two low tides a day, the high and low alternating at approximately six-hour intervals.

62.
This idea had been advanced by one of Galileo's teachers at the University of Pisa, Girolamo Borro (1512–92), in
Dialogo del flusso e reflusso del mare
(Lucca, 1561).

63.
Ellipsis in Galileo's text, to convey the impression that Sagredo interrupts Simplicio's speech.

64.
Pseudo-Aristotle,
Questions of Mechanics
, no. 1, 847a11.

65.
In this parenthetical clause, the translation in Finocchiaro 1997, 286, has been corrected slightly.

66.
In this speech by Sagredo, the translation in Finocchiaro 1997, 286, has been corrected by changing “useless” to “false” and “miracles” to “the miracle.”

67.
The city of Venice, where this book's discussion occurs, is built on many small islands separated by canals and located in the middle of a shallow bay, the Lagoon of Venice; this bay is separated from the Adriatic Sea by a series of long and narrow islands, one of which is the Lido. The tides are especially noticeable there.

68.
This explanation is distinct from the ones discussed above. According to Sosio (1970, lxxiv), it is found in several authors of classical antiquity, the medieval Arab world, and the Renaissance (including Leonardo da Vinci).

69.
The last two paragraphs contain an approximation to an important law in hydrodynamics. Combining the two points, Galileo says that the period of oscillation of water in a vessel varies directly with the length of the vessel and inversely with its depth. The relationship is actually more complicated insofar as the dependence on the length involves its square root. Cf. Strauss 1891, 568 n. 9; Pagnini 1964, 3: 243 n. 1.

70.
This remark seems to contradict Salviati's claim in the penultimate sentence of this speech, namely, that he has under construction such a machine.

Perhaps Galileo meant not that it is impossible but that it is very difficult. For an attempt to resolve the apparent contradiction, see Drake 1970, 200–13.

71.
By
degree
, here Galileo means 1 of 360 degrees in a circle; so, when the circle is the equator (which is about 24,000 miles), one degree is about sixty-seven miles.

72.
This is not a true story, and later in Day IV Galileo himself treats it as a mere legend (Galilei 1890–1901, 7: 472; 1967, 447). In fact, Aristotle discusses the tides only briefly in
Meteorology
I, 1.

73.
This refers to the Strait of Messina separating the island of Sicily from Calabria on the Italian peninsula and joining the Ionian and the Tyrrhenian Seas.

74.
This is the ancient mythological name for the Strait of Gibraltar, separating Europe from Africa, and connecting the Mediterranean Sea and the Atlantic Ocean.

75.
The monthly period of the tides is the phenomenon that during certain times of the month the daily high tides are higher than usual and the daily low tides are lower than usual; similarly, the annual period is the phenomenon that during certain periods of the year the daily high tides are higher and the daily low tides lower than usual.

76.
Galilei 1890–1909, 7: 485.36–489.20; translated by Finocchiaro (1997, 303–8).

77.
In a marginal note Galileo identifies this author as Seleucus.

78.
That is, the annual parallax of fixed stars, which however was not detected until 1838, by Friedrich W. Bessel.

79.
Cesare Marsili (1592–1633) was a patron and friend of Galileo's and an amateur scientist. Marsili's essay has been lost and so it is impossible to evaluate his alleged discovery. But it is likely that the reported deviation of the meridian was due to observational error, and in any case it is unclear how the deviation would have supported the earth's motion.

80.
This refers to Pope Urban VIII, who found the objection Simplicio proceeds to state a powerful and indeed unanswerable argument against Coper-nicanism; Galileo knew the pope's opinion from personal discussions during special audiences, first in 1624 after the pope's election, when Galileo went to Rome to pay him homage, and then again in 1630 after Galileo had finished his book and visited that city to get permission to publish it. The lengthy negotiations for this purpose included the stipulation that he would end the book with this argument.

81.
Cf. Ecclesiastes, 3:10–11 (King James Version): “I have seen the travail, which God hath given to the sons of men to be exercised in it. He hath made every
thing
beautiful in his time: also he hath set the world in their heart, so that no man can find out the work that God maketh from the beginning to the end.”

CHAPTER 9
¹

From the Later Trial-Documents (1632–33)
²

§9.1 Special Commission's Report on the
Dialogue
(September 1632)
³

[ §9.1.1] In accordance with the order of Your Holiness, we have laid out the whole series of events pertaining to the printing of Galilei's book, which printing then took place in Florence. In essence the affair developed this way.

In the year 1630 Galileo took his book manuscript to the Father Master of the Sacred Palace in Rome, in order to have it reviewed for printing. The Father Master gave it for review to Father Raffaello Visconti, a friend of his and a professor of mathematics, who after several emendations was ready to give his approval as usual, if the book were to be printed in Rome.

We have written the said Father to send the said certificate, and we are now waiting for it. We have also written to get the original manuscript, in order to see the corrections made.

The Master of the Sacred Palace wanted to review the book himself; but, in order to shorten the time and to facilitate negotiations with printers, he stipulated that it be shown him page by page, and gave it the imprimatur for Rome.

Then the author went back to Florence and petitioned the Father Master for permission to print it in that city, which permission was denied. But the latter forwarded the case to the Inquisitor of Florence, thus removing himself from the transaction. Moreover, the Father Master notified the Inquisitor of what was required for publication, leaving to him the task of having it printed or not.

The Master of the Sacred Palace has shown a copy of the letter he wrote the Inquisitor about this business, as well as a copy of the Inquisitor's reply to the said [325] Master of the Sacred Palace. In it the Inquisitor says that he gave the manuscript for correction to Father Stefani, consultant to the Holy Office.

After this the Master of the Sacred Palace did not hear anything, except that he saw the book printed in Florence and published with the Inquisitor's imprimatur, and that there is also an imprimatur for Rome.

We think that Galileo may have overstepped his instructions by asserting absolutely the earth's motion and the sun's immobility and thus deviating from hypothesis; that he may have wrongly attributed the existing ebb and flow of the sea to the nonexistent immobility of the sun and motion of the earth, which are the main things; and that he may have been deceitfully silent about an injunction given him by the Holy Office in the year 1616, whose tenor is: “that he abandon completely the above-mentioned opinion that the sun is the center of the world and the earth moves, nor henceforth hold, teach, or defend it in any way whatever, orally or in writing; otherwise the Holy Office would start proceedings against him. He acquiesced in this injunction and promised to obey.”

One must now consider how to proceed, both against the person and concerning the printed book.

[ §9.1.2] In point of fact:

1. Galilei did come to Rome in the year 1630, and he brought and showed his original manuscript to be reviewed for printing. Though he had been ordered to discuss the Copernican system only as a pure mathematical hypothesis, one found immediately that the book was not like this, but that it spoke absolutely, presenting the reasons for and against though without deciding. Thus the Master of the Sacred Palace determined that the book be reviewed and be changed to the hypothetical mode: it should have a preface to which the body would conform, which would describe this manner of proceeding, and which would prescribe it to the whole dispute to follow, including the part against the Ptolemaic system, carried on merely ad hominem and to show that in reproving the Copernican system the Holy Congregation had heard all the arguments.

2. To follow this through, the book was given for review with these orders to Father Raffaello Visconti, a friend of the Master of the Sacred Palace, since he was a professor of mathematics. He reviewed it and emended it in many places, informing the Master about others disputed with the author, which the Master took out without further discussion. Having approved it for the rest, Father Visconti was ready to give it his endorsement to be placed at the beginning of the book as usual, if the book were to be printed in Rome as it was then presumed.

We have written the Inquisitor to send this endorsement to us and are expecting to receive it momentarily, and we have also sent for the original so that we can see the corrections made.

3. The Master of the Sacred Palace wanted to review the book himself, but, since the author complained about the unusual practice of a second revision and about the delay, to facilitate the process it was decided that before sending it to press the Master would see it page by page. In the meantime, to enable the author to negotiate with printers, he [326] was given the imprimatur for Rome, the book's beginning was compiled, and printing was expected to begin soon.

4. The author then went back to Florence, and after a certain period he petitioned to print it in that city. The Master of the Sacred Palace absolutely denied the request, answering by saying that the original should be brought back to him to make the last revision agreed upon, and that without this he for his part would have never given permission to print it. The reply was that the original could not be sent because of the dangers of loss and the plague. Nevertheless, after the intervention of His Highness there, it was decided that the Master of the Sacred Palace would remove himself from the case and refer it to the Inquisitor of Florence: the Master would describe to him what was required for the correction of the book and would leave him the decision to print it or not, so that he would be using his authority, without any responsibility on the part of the Master's office. Accordingly, he wrote to the Inquisitor the letter whose copy is appended here, labeled A, dated 24 May 1631, received and acknowledged by the Inquisitor with the letter labeled B, where he says he entrusted the book to Father Stefani, consultant to the Holy Office there.

Then a brief composition of the book's preface was sent to the Inquisitor so that the author would incorporate it with the whole, would embellish it in his own way, and would make the ending of the
Dialogue
conform with it. A copy of the sketch that was sent is enclosed labeled C, and a copy of the accompanying letter is enclosed labeled D.

5. After this the Master of the Sacred Palace was no longer involved in the matter, except when, the book having been printed and published without his knowledge, he received the first few copies and held them in customs, seeing that the instructions had not been followed. Then, upon orders from Our Master, he had them all seized where it was not too late and diligence made it possible to do so.

6. Moreover, there are in the book the following things to consider, as specific items of indictment:

i.
⁴
That he used the imprimatur for Rome without permission and without sharing the fact of the book's being published with those who are said to have granted it.

ii. That he had the preface printed with a different type and rendered it useless by its separation from the body of the work; and that he put the “medicine of the end” in the mouth of a fool and in a place where it can only be found with difficulty, and then he had it approved coldly by the other speaker by merely mentioning but not elaborating the positive things he seems to utter against his will.

iii. That many times in the work there is a lack of and deviation from hypothesis, either by asserting absolutely the earth's motion and the sun's immobility, or by characterizing the supporting arguments as demonstrative and necessary, or by treating the negative side as impossible. iv. He treats the issue as undecided and as if one should await rather than presuppose the resolution.

[327] v. The mistreatment of contrary authors and those most used by the Holy Church.

vi. That he wrongly asserts and declares a certain equality between the human and the divine intellect in the understanding of geometrical matters.

vii. That he gives as an argument for the truth the fact that Ptolemaics occasionally become Copernicans, but the reverse never happens. viii. That he wrongly attributed the existing ebb and flow of the sea to the nonexistent immobility of the sun and motion of the earth.

All these things could be emended if the book were judged to have some utility which would warrant such a favor.

7. In 1616 the author had from the Holy Office the injunction that “he abandon completely the above-mentioned opinion that the sun is the center of the world and the earth moves, nor henceforth hold, teach, or defend it in any way, orally or in writing; otherwise the Holy Office would start proceedings against him. He acquiesced in this injunction and promised to obey.”

§9.2 Galileo's First Deposition (12 April 1633)
⁵

Summoned, there appeared personally in Rome at the palace of the Holy Office, in the usual quarters of the Reverend Father Commissary, fully in the presence of the Reverend Father Fra Vincenzo Maculano of Firenzuola, [337] Commissary General, and of his assistant Reverend Father Carlo Sinceri, Prosecutor of the Holy Office, etc.

Galileo, son of the late Vincenzio Galilei, Florentine, seventy years old, who, having taken a formal oath to tell the truth, was asked by the Fathers the following:

Q:
⁶
By what means and how long ago did he come to Rome.

A: I arrived in Rome the first Sunday of Lent, and I came in a litter.

Q: Whether he came of his own accord, or was called, or was ordered by someone to come to Rome, and by whom.

A: In Florence the Father Inquisitor ordered me to come to Rome and present myself to the Holy Office, this being an injunction by the officials of the Holy Office.

Q: Whether he knows or can guess the reason why he was ordered to come to Rome.

A: I imagine that the reason why I have been ordered to present myself to the Holy Office in Rome is to account for my recently printed book. I imagine this because of the injunction to the printer and to myself, a few days before I was ordered to come to Rome, not to issue any more of these books, and similarly because the printer was ordered by the Father Inquisitor to send the original manuscript of my book to the Holy Office in Rome.

Q: That he explain the character of the book on account of which he thinks he was ordered to come to Rome.

A: It is a book written in dialogue form, and it treats of the constitution of the world, that is, of the two chief systems, and of the arrangement of the heavens and the elements.

Q: Whether, if he were shown the said book, he is prepared to identify it as his.

A: I hope so; I hope that if the book is shown me I shall recognize it.

And having been shown one of the books printed in Florence in 1632, whose title is
Dialogue of Galileo Galilei Lincean
etc., which examines the two systems of the world, and having looked at it and inspected it carefully, he said: I know this book very well; it is one of those printed in Florence; and I acknowledge it as mine and written by me.

Q: Whether he likewise acknowledges each and every thing contained in the said book as his.

A: I know this book shown to me, for it is one of those printed in Florence; and I acknowledge all it contains as having been written by me.

Q: When and where he composed the said book, and how long it took him.

[338] A: In regard to the place, I composed it in Florence, beginning ten or twelve years ago; and it must have taken me seven or eight years, but not continuously.

Q: Whether he was in Rome other times, especially in the year 1616, and for what occasion.

A: I was in Rome in the year 1616; then I was here in the second year of His Holiness Urban VIII's pontificate; and lastly I was here three years ago, the occasion being that I wanted to have my book printed. The occasion for my being in Rome in the year 1616 was that, having heard objections to Nicolaus Copernicus' opinion on the earth's motion, the sun's stability, and the arrangement of the heavenly spheres, in order to be sure of holding only holy and Catholic opinions, I came to hear what was proper to hold in regard to this topic.

Q: Whether he came of his own accord or was summoned, what the reason was why he was summoned, and with which person or persons he discussed the above-mentioned topics.

A: In 1616 I came to Rome of my own accord, without being summoned, for the reason I mentioned. In Rome I discussed this matter with some cardinals who oversaw the Holy Office at that time, especially with Cardinals Bellarmine, Aracoeli, San Eusebio, Bonsi, and d'Ascoli.

Q: What specifically he discussed with the above-mentioned cardinals.

A: The occasion for discussing with the said cardinals was that they wanted to be informed about Copernicus' doctrine, his book being very difficult to understand for those who are not professional mathematicians and astronomers. In particular they wanted to understand the arrangement of the heavenly spheres according to Copernicus' hypothesis, how he places the sun at the center of the planets' orbits, how around the sun he places next the orbit of Mercury, around the latter that of Venus, then the moon around the earth, and around this Mars, Jupiter, and Saturn; and in regard to motion, how he makes the sun stationary at the center and the earth turn on itself and around the sun, that is, on itself with the diurnal motion and around the sun with the annual motion.

Q: Since, as he says, he came to Rome to be able to have the resolution and the truth regarding the above, what then was decided about this matter.

A: Regarding the controversy which centered on the above-mentioned opinion of the sun's stability and earth's motion, it was decided by the Holy Congregation of the Index that this opinion, taken absolutely, is repugnant to Holy Scripture, and that it is to be admitted only suppositionally, in the way that Copernicus takes it.

Q: Whether he was then notified of the said decision, and by whom.