Galileo Galilei (1564-1642) is widely known for his discoveries of the Moon craters, for his discovery of four of the Jupiter's moons, for the "experiment" of dropping weights from the top of the so-called Leaning Tower of Pisa, and many other important scientific contributions to astronomy, mathematics, and physics.
Galileo is also inevitably connected with the "invention" of the telescope, and most notably known by the discoveries he made when methodically began observing the night skies with the aid of his new optical artifacts. With his telescopes always under constant perfection he also discovered and made drawings of the Moon's surface irregularities, like craters and valleys. The four moons of Jupiter that he discovered between 1609 and 1610 are: Io, Europa, Ganymede, and Callisto; these moons are called the Galilean Moons in his honor.
The doubtful "Leaning Tower of Pisa experiment" supposedly consisted of dropping two different-weight balls —and possibly different materials— ten, and one pound balls, some say from the Leaning Tower of Pisa with the objective of demonstrating that they will hit the ground at the same time, and not as intuition would tell us that the heavier one will hit the ground first.
However, there is a long debate about the veracity of the narrative of this experiment because he never mentions it, and because at that time there were no accurate means of telling or measuring the time differences when the balls hit the ground. On the other hand, similar experiments are said to be carried away by Benedetti Giambattista in 1553 and by Simon Stevin in 1586. Maybe, for Galileo, it was a "thought experiment".
But there is one transcendental event of life that involves not only him and his experiments, but also the clerical authorities of his time: it is the the so-called indictment and abjuration of Galileo of his astronomical ideas because they were against the Christian Church's teachings. But before going deep into this, let us bring into the scene some previous historic facts that led to the confrontation between Galileo and the Roman Church.
Nicolaus Copernicus (1473-1543) received in his hands a copy of the "work of his life", the book De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) where he stated the foundations for a solid heliocentric solar system where he placed the Sun —and not the Earth, as was commonly accepted— as the center about which all other planets are rotating.
It is said that he received the first printed sample the same year of his death. Copernicus book is among the group of books that changed history and brought a heated debate that even today for some fundamentalist people is not fully settled.
However, the work of Copernicus had many previous contributions upon which Copernicus relied. Among them were thinkers so back in times as Aristarchus of Samos (310 BC - ca. 230 BC) —who is considered the true predecessor of Copernicus, and thus called the Greek Copernicus, Seleucus (ca. 358 BC–281 BC), John Philoponus (490-570), and others. But at the time of Copernicus, the Universe was neither considered nor conceived without a center. But Copernicus displaced the Earth from the center of the Universe. However, the Earth's distance to the center of the Universe was small compared to the fixed stars.
Copernicus had completed his monumental work 36 years before the its publication. But he refrained from publishing it because "maybe it was better to follow the example of the Pythagorean and others".
His great work "De Revolutionibus orbium coelestium" was published at the earnest solicitation of two distinguished churchmen, Cardinal Schömberg and Tiedemann Giese, Bishop of Culm. It was dedicated by permission to Pope Paul III in order, as Copernicus explained, that it might be thus protected from the attacks which it was sure to encounter on the part of the "mathematicians" (i.e. philosophers) for its apparent contradiction of the evidence of our senses, and even of common sense.1
Stating that the Earth is not the center of the Solar System is not a simple exercise of substituting one cosmic body for another: the new Copernicus' astronomy was not a simple geometrical exercise of interchanging point of references.
Copernicus' new planetary movement implied that the Earth was not static, that the Earth was moving, and those assertions were difficult to believe because we don't feel any movement under our feet. What we daily see is the Sun rising from one side of the horizon and setting in the afternoon in the opposite side.
We don't feel the Earth moving under us and we don't feel like moving to anywhere. In fact, what we feel is like being at the very center of everything. But if everybody feels the same, then there is no single center, so some kind of optical or sensory illusion must be always surrounding us. At the time of Copernicus, there was no mean to counter-argument those who said that a moving Earth would leave its atmosphere behind.
Copernicus didn't included any proof that the Earth is moving around the Sun neither rotating around its own axis: at that time there was no conclusive means of proving those facts. It would take Friedrich Bessel in 1836, and Léon Foucault in 1851 to show simple demonstrations for those concepts respectively.
So up to here, there was no confrontation between science and religion, at least, in visible form or with no mayor polemics, mainly because Copernicus' ideas were somewhat harmless, because at the end of the road there were no solid physical evidence to prove his axioms.
In March, 1610, Galileo published his little book: Sidereus Nuncius (Starry Messenger), the book where he included the sketches he made of the lunar craters and his discoveries of the moons of Jupiter.
Sidereus is a very small book with a noticeably long title (Sidereus Nuncius is just the beginning). In the long title of the book, he uses the term Perspicilli that is the plural of Perspicillum, the term previously used for telescope until Della Porta introduced the term telescopium in 1611.
It is now known that Galileo was not the first to use a telescope to observe the Moon and to make drawings of its irregularities, but he was the first to make a systematic compendium of his observations and to follow methodically the moons of Jupiter.
Some authors insist that Galileo did not fully understood the real optical behavior of the telescopes he used, but the reality is that this was no handicap to use it on the whole to create and write such a revolutionary work.
The appearance of this book immediately unleashed an acid controversy for three main reasons:
If Copernicus' book placing the Sun at the center of the Solar system —thus removing the Earth from that central position— was dedicated to Pope Paul III and it was welcomed, why then Galileo had such a bad luck when was called to the Inquisition court? Well, it was matter of time; somebody, sometime, was going to respond for those challenging ideas. Back in 1616, On the Revolutions of the Celestial Spheres of Copernicus was placed in the Church Index of prohibited books "until it were corrected''. So the seed for a confrontation between science and religion had already germinated in Copernicus' book; but now only Galileo was there to answer the questions of the Church.
The opposition to Copernicus' book and the confrontation with Galileo were part of two different controversies.
The conflict between the Bible and Copernicus were based in Bible's Joshua (10:13),
13 And the sun and the moon stood still, till the people revenged themselves of their enemies. Is not this written in the book of the just? So the sun stood still in the midst of heaven, and hasted not to go down the space of one day.
and Isaiah (38:7-8) :
7 And this shall be a sign to thee from the Lord, that the Lord will do this word which he hath spoken: 8 Behold I will bring again the shadow of the lines, by which it is now gone down in the sun dial of Achaz with the sun, ten lines backward. And the sun returned ten lines by the degrees by which it was gone down.
In this explicit confrontation of the Bible verses against Copernicus, Luther and Melanchthon inevitably took stand against him, and against science and reasoning, arguing on the basis of pure faith only. Martin Luther was so convinced of the credibility of the Bible and the incorruptibility of the skies that he is credited referring to comets as "harlot stars and works of the devil".
On the other hand, the confrontation with Galileo was based mainly on other more refined grounds: the physics of Aristotle. For this, in 1611, cardinal Robert Bellarmine, chief theologian of the Church, asked the master Jesuit mathematicians and astronomers to study in details the claims of Copernicus and Galileo for the evident antagonism with the Bible and the Aristotelian and Pythagorean doctrines.
The controversy between Galileo and the Jesuits (former friends and admirers of him) grew up an up until he was summoned to Rome. The showdown began and took an inevitably impulse that even today seems impossible to stop. Lots of opinions, research, and debate is still under the public consideration. There are hundreds of articles, books, paintings, poems, even drama, about the trial of Galileo, so our concern here is the recantation text (the last paragraphs), because it summarizes the long and agonizing last days of Galileo.
I, Galileo, son of the late Vincenzo Galilei, Florentine, aged seventy years, arraigned personally before this tribunal, and kneeling before you, Most Eminent and Reverend Lord Cardinals, Inquisitors-General against heretical depravity throughout the entire Christian commonwealth, having before my eyes and touching with my hands, the Holy Gospels, swear that I have always believed, do believe, and by God's help will in the future believe, all that is held, preached, and taught by the Holy Catholic and Apostolic Church. But whereas -- after an injunction had 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 this new doctrine already condemned, and adduce arguments of great cogency in its favor, without presenting any solution of these, and for this reason 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 Eminences, and of all faithful Christians, this vehement suspicion, justly conceived against me, with sincere heart and unfeigned faith I abjure, curse, and detest the aforesaid errors and heresies, and generally every other error, heresy, and sect whatsoever contrary to the said Holy Church, and I swear that in the future I will never again say or assert, verbally or in writing, anything that might furnish occasion for a similar suspicion regarding me; but that 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. And, in the event of my contravening, (which God forbid) any of these my promises and oaths, I submit myself to all the pains and penalties imposed and promulgated in the sacred canons and other constitutions, general and particular, against such delinquents. So help me God, and these His Holy Gospels, which I touch with my hands.
I, the said Galileo Galilei, have abjured, sworn, promised, and bound myself as above; and in witness of the truth thereof I have with my own hand subscribed the present document of my abjuration, and recited it word for word at Rome, in the Convent of Minerva, this twenty-second day of June, 1633.
I, Galileo Galilei, have abjured as above with my own hand. 2
Galileo was the author of many books: the Starry Messenger was only one of them. Some of the other works by him are: Letters on Sunspots, Discourse on the Tides, Discourse on the Comets, The Assayer, Dialogue Concerning the Two Chief World Systems, Discourses and Mathematical Demonstrations Relating to Two New Sciences. That is, Galileo was very akin to the "discourses", so his "abjuration" in front of the Inquisition Tribunals was maybe his last and perhaps best discourse.
Who can really trust Galileo when he says that ...
... after an injunction had 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 ...
Who is abjuring? Galileo? The same one that wrote and ardently debated in favor of what is now renouncing?
Galileo was a man of science, and even when he was kneeling before you, Most Eminent and Reverend Lord Cardinals, Inquisitors-General he was still a man of science. But surely, as a prolific writer as he was, he knew that his words were going to be saved for the posterity, like the Starry Messenger was.
Therefore, by his presence in the Holy Office he was writing the discourse of his life. His "recanting" had an underlying purpose: by going "personally before this tribunal" he was using the Church power to project himself forever to posterity.
Surely he envisioned that someday, in some unknown ways, somebody will definitely demonstrate what he and Copernicus were unable to do. And this was the case: as mentioned above, Bessel, Foucault, and Newton were among the many that laid the foundations for a new and solid science of the skies, and a new philosophy of science based on Copernicus, and Galileo.
But Galileo was also the father of two nuns; thus, certainly, he was not going to let them suffer forever for his actions. Paternity is very strong at that age (he was 70). Before him were his jurors, but also in his mind was the presence of his daughters, Virginia (later Sister Maria Celeste) and Livia (later Sister Arcangela). He was almost blind, therefore, he had no intentions —as he was impeded— to write more books. Hence, he let the Church write his last discourse for him; and they did it.
Galileo abjuring from his science? Never in the life! Science cannot be abjured. Science is not based on acts of faith. Science cannot be brought to the rulings and conclusions of judges. Scientific experimental data judicially and fairly collected and analyzed cannot be negated. Therefore, the abjuration of Galileo was possibly ... an act of vengeance.
E. Pérez
10/10
1. Gerard, J. (1909). Galileo Galilei. In The Catholic Encyclopedia. New York: Robert Appleton Company.
2. Famous Trials. Recantation of Galileo. University of Missouri-Kansas City (UMKC) School of Law.
History of the Conflict Between Religion and Science
The Deluge In The Light Of Modern Science