Q. & A.
Question: What was the Church’s objection to the teaching of Copernicus and Galileo on the arrangement of the Solar System? Did the Church overstep its authority on matters of faith and morals by claiming to settle a scientific question? In general, how can science be reconciled with the Catholic Faith?
answer the last question first, the Church insists that truth is
“unitary”; which is to say that it is impossible to arrive at different
truths when asking the same question from the standpoint of different
intellectual disciplines. While the degree of overlap between science
and religion (or between two different sciences) may not be great, they both
seek the same truth. When some physical reality is clearly demonstrated
to be true, then any seemingly contradictory scriptural references to the
phenomenon must be understood as being metaphorical. Romans 10:18, for
example, was cited by some early Christians as proof that no one lived below the equator: “[The Apostles] hath gone forth into
all the earth: and their words unto the ends of the whole world.”
Therefore, since they had not preached to anyone south of the equator, there
must not be anyone south of the equator! When early 16th
century explorers like Magellan crossed the equator and encountered people
living far to the south, it became obvious that the preaching of the Apostles
must have been only to the world known at the time of Saint Paul.
Leo XIII stated this concept authoritatively in Providentissimus Deus
(18 November 1893).[i]
He began by citing a passage of Saint Augustine’s, which was repeated by
Cardinal Bellarmine during the Galileo case: “Whatever
they can really demonstrate to be true of physical nature we must show to be
capable of reconciliation with our Scriptures; and whatever they assert in
their treatises, which is contrary to these Scriptures of ours, that is to
Catholic faith, we must either prove it as well as we can to be entirely
false, or at all events we must, without the smallest hesitation, believe it
to be so.”
understand how just is the rule here formulated we must remember, first, that
the sacred writers, or to speak more accurately, the Holy Spirit "who
spoke by them, did not intend to teach men these things (that is to say, the
essential nature of the things of the visible universe), things in no way
profitable unto salvation." Hence they did not seek to penetrate
the secrets of nature, but rather described and dealt with things in more or
less figurative language, or in terms which were commonly used at the time,
and which in many instances were daily used at this day, even by the most
eminent men of science. Ordinary speech primarily and properly describes what
comes under the senses; and somewhat in the same way the sacred writers -- as
the Angelic Doctor also reminds us --"went by what sensibly
appeared," or put down what God, speaking to men, signified, in the way
men could understand and were accustomed to.
It is the business of priests to tell us how to go to heaven; it
is the business of scientists to tell us how the heavens go.
It can be argued that Galileo was unfairly treated, but like most
real-world debates, his case was much too complicated to dismiss as
“religion vs. science.” To begin with, we will see what the
Scriptures actually said about the created universe.
Pope Leo XIII stated this concept authoritatively in Providentissimus Deus (18 November 1893).[i] He began by citing a passage of Saint Augustine’s, which was repeated by Cardinal Bellarmine during the Galileo case:
“Whatever they can really demonstrate to be true of physical nature we must show to be capable of reconciliation with our Scriptures; and whatever they assert in their treatises, which is contrary to these Scriptures of ours, that is to Catholic faith, we must either prove it as well as we can to be entirely false, or at all events we must, without the smallest hesitation, believe it to be so.”
To understand how just is the rule here formulated we must remember, first, that the sacred writers, or to speak more accurately, the Holy Spirit "who spoke by them, did not intend to teach men these things (that is to say, the essential nature of the things of the visible universe), things in no way profitable unto salvation." Hence they did not seek to penetrate the secrets of nature, but rather described and dealt with things in more or less figurative language, or in terms which were commonly used at the time, and which in many instances were daily used at this day, even by the most eminent men of science. Ordinary speech primarily and properly describes what comes under the senses; and somewhat in the same way the sacred writers -- as the Angelic Doctor also reminds us --"went by what sensibly appeared," or put down what God, speaking to men, signified, in the way men could understand and were accustomed to.
It is the business of priests to tell us how to go to heaven; it is the business of scientists to tell us how the heavens go.
It can be argued that Galileo was unfairly treated, but like most real-world debates, his case was much too complicated to dismiss as “religion vs. science.” To begin with, we will see what the Scriptures actually said about the created universe.
The earth itself was immovable:
But the view of the universe held by western civilization since the time of Pythagoras (6th century BC) was not that of the Old Testament. One philosopher, Aristarchus of Samos (3rd century BC), held that the Sun was at the center of the universe. But that defied the common experience of mankind—we have all stood on a very stable Earth and observed the motion of the heavens—very few have stood anywhere else. Instead, following Pythagoras, the universe was thought by most to be a complex series of interlocking nested crystalline spheres centered on the Earth and extending outward to the Empyrean Heaven (see illustration[viii]). The Moon, the Sun, and the stars were attached to the various spheres, and moved by virtue of a force imparted by God in Heaven at the outer sphere. Pythagoras’ theory was expressed mathematically by Eudoxus of Cnidos (4th century BC), and incorporated into the works of Aristotle (384-322 BC).
Aristotle had something important to say about every conceivable topic of interest to the ancient world. Some of his works are quite valid today, and others, like his Physics and Astronomy, were considered authoritative until the time of Galileo at least. Many of his writings were lost in the West at the time of the Barbarian Invasions, and were recovered only at the time of the Crusades, when they were re-discovered in Arabic translations. Translated into Latin, the missing works not only enhanced Aristotle’s prestige, but formed the basis for Saint Thomas Aquinas’ (1225-1274) comprehensive philosophy and theology, in many ways replacing earlier works based on the teaching of Plato. By the time of the Council of Trent (1545-1563), Aquinas’ works were considered to be of such authority that they were placed on the altar with the Scriptures during Council sessions. By the 16th century, a challenge to Aristotle was beginning to look like a challenge to Western scholarship, including its theology.
A number of Aristotle’s physical theories were based not on observation but on what he felt to be logically true. But so great was his authority (and that of other ancient scholars) that he went pretty much unchallenged until the seventeenth century. Before that time, scholarship amounted to little more than a knowledge of what the ancients had to say about the topic at hand. A very few, such as the Franciscan Roger Bacon (1214-1294), and the Dominican Saint Albert the Great (1206-1280) insisted that “The aim of natural science is not merely to accept the statements of others, but to investigate the causes that are at work in nature.... Experiment is the only safe guide in such investigations.”[ix] Only in the 14th century did Jean Buridan (c. 1300-1361) dispute Aristotle’s theory that bodies were moved by the rush of air behind them with a new theory that “impetus” was imparted to the moving object by the mover—not quite correct by modern standards but an unprecedented challenge to “science by authority.”[x] But, for the most part, Aristotle reigned supreme for close to two-thousand years. As late as 1614 their Superior General, Claudio Acquaviva, forbade the Jesuits to repudiate Aristotle![xi]
Sixteenth century science was far more qualitative than quantitative—it relied more heavily on a reasonable explanation of the phenomenon at hand than any sort of mathematical demonstration. Indeed, mathematics were considered, at best, an abstraction of the real world—or maybe even an abstraction of the unreal. It was far more important to demonstrate that a scientific theory squared well with the general body of knowledge (including philosophy and theology) than to provide descriptive mathematics. Both Copernicus and Galileo were encouraged by their supporters to present the heliocentric model of the universe as a convenience for mathematical computation but not as a model of what was actually happening in the real world. On one hand, the general consideration of mathematics as pure abstraction shielded new theories from the criticism of the establishment, but, on the other hand, it protected the established theories from the modern requirement to demonstrate mathematical consistency.
Nicholaus Copernicus (1473-1543) a Canon of Frauenburg, and possibly a priest, contributed to the astronomical observations and calculations which eventually resulted in Pope Gregory XIII’s reform of the calendar in 1582. He was reluctant to publish his heliocentric theory, and it was not until he was on his deathbed that it appeared in print. Unbeknownst to Copernicus it was published by the Protestant, Andreas Osiander, with a preface indicating that the theory was a mathematical abstraction and not a physical fact. Even with this spurious preface the work was condemned by Melanchthon and Luther in 1539:
The Copernican theory went uncriticized by Catholics until 1616 when it was vigorously defended as real—not just an aid to calendar calculations—by Galileo.
The Copernican system, of course, placed the Sun at the center of the universe, but it retained the circular orbits (“deferents”) and a good deal of the complexity of the Ptolemaic system. From the Earth, the planets sometimes appear to change speed or even reverse direction. In order to explain this apparently irregular motion of the planets among the perfect celestial spheres, Ptolemy had to resort to having the Earth a bit off center, and to having the planets move in additional circles called “epicycles” which somehow hung on the orbital “deferents” of the crystalline spheres. This amounted to about eighty circles, many of which intersected. Copernicus reduced the complexity by about a third, but still gave no indication as to how the planets could be moving in such circles without the use of the celestial spheres.[xii]
The Church’s position was that It was willing to interpret the Scriptural references to the rising and setting Sun metaphorically—but only if the scientists gave convincing proof that the Copernican system was true and the Ptolemaic system false. Reducing the number of “epicycles” and “deferents” was not enough—particularly not enough to deny the common experience of men. There were other problems as well.
Why were there “epicycles” at all? They were, largely, a mathematical abstraction, employed to make things “work out” in accordance with what men actually saw. It did not help to insist that they were real. Copernicus pointed to the Moon going around the Earth as an example of a circle attached to a circular orbit. Galileo would later point to the moons of Jupiter, discovered in his telescope, as another example of real “epicycles.” But that helped not at all to explain why Mercury and Venus might follow circles around nothing at all in their orbital paths. Galileo, insisting that circular motion was somehow “natural” and self sustaining refused to entertain the elliptical orbits (correctly) calculated by his friend Johann Kepler—abandoning the circular orbit for the elliptical orbit would have eliminated all of the artificial “epicycles” and more accurately predicted the paths of the moons!
Movement toward the center of the Earth, as the center of all things was merely “natural” under the old system, and the spheres could easily be understood as “balanced” around the central Earth. Moving the center of the universe from the Earth to the Sun required an explanation of why things were naturally pulled toward the Earth, as well as an explanation of how the huge bulk of the Earth might be forced to revolve about the Sun. Galileo was never able to overcome his own Aristotelian prejudice and recognize that straight line (not circular) motion is “natural,” and that anything else required the application of a force—that would take Isaac Newton’s (1643-1727) theory of gravity, a number of years in the future.
Galileo and Ptolemy were also off in their explanation of comets as phenomena within the Earth’s atmosphere. Both tried to maintain the unchangeable nature of the heavenly bodies (in spite of Psalm 101). Kepler placed the comets in elliptical orbits like the planets, which correctly predicted their periodic returns.
Galileo was simply in error about the tides, which he claimed to be caused by the Earth’s revolution and rotation. These high speed movements don’t cause the water to move out of the sea bed, for the water is moving with the same motion and speed as the Earth. Notice that there is no thousand mile per hour wind! Eager to “shoot him down,” the astrologers were quick to point out that the tides were already known to be caused by the influence of the Moon and Sun—perhaps the only tangible evidence they had to prove the validity of their own “science.”
Apart from the scientific problems with Galileo’s theory, there were a number of “human problems.
Galileo had the misfortune of coming on the scene shortly after Giordano Bruno (1548-1600), an ex-Dominican priest who preached a number of heresies, including the salvation of the Devil and the denial of the divinity of Christ. Bruno taught that mathematics was a form of “natural magic,” and derived some offbeat theological notions from the Copernican theory. That Bruno, identified as a Copernican, was wanted (or unwanted) in a number of European countries, and excommunicated by the Anglicans, the Calvinists, and the Catholics before being burned at the stake, did Galileo absolutely no good![xiii]
Nor did it help that Galileo took delight in vanquishing his opponents in debate. A genius who actually understood the things with which he dealt, he was often confronted by men who had done little more than memorize Aristotle. But these were the Dominicans and Jesuits who would exercise considerable power over him and his publications.
In 1616, the Inquisition took an interest, and Galileo was called before the Inquisition to discuss his early writings. In a letter of May 26th 1616, requested by Galileo, Cardinal Bellarmine stated succinctly that he had not been asked to abjure anything nor to perform any sort of penance:
Galileo was justified in feeling that this letter permitted him to pursue theoretical research on the Copernican system. He was not aware of another document, irregularly placed in his file by the Inquisition, claiming that he had been told to:
The letter is generally considered false for it lacked the customary notarized acceptance of the one whom it concerned—Galileo. Some years later, in 1630, after Bellarimine’s death and the election of Maffeo Barberini as Urban VIII, Galileo received positive encouragement from the Pope himself to put his ideas into writing; Urban even furnished Galileo with an argument against the Copernican system, and suggested that the title be On the Two Chief World Systems. (Galileo’s title was Dialogue on the Great World Systems.)
Galileo’s fatal mistake was that in the Dialogue he put Urban’s arguments against Copernicism in the mouth of one of the fictional characters—the one named Simplicio—implying that he was a simpleton. Yet the work was licensed to be printed at Rome, and probably would have been except for the death of his Roman patron, Prince Federico Cesi. Galileo, then at Florence, and unable to communicate with his friends in Rome due to an outbreak of the Plague (!) arranged to have the book printed locally and with a Florentine imprimatur.[xvi]
Urban was not an aristocrat and might have ignored being cast as Simplicio if he had not lost his sense of humor to other personal difficulties. He had been fighting against the wrong side in the Thirty Years War, had squandered a good deal of money and ancient art treasures on building projects, and was guilty of serious nepotism in his appointments. Father James Brodrick, SJ paints the picture:
On June 22nd 1633, in a somewhat humiliating ceremony, Galileo was forced, on his knees, to “abandon the false opinion that the sun is the center of the world ... and that the earth is not the center of the world and moves.”[xix] He was subject to perpetual house arrest; his beloved daughter, Sister Maria Celeste, died in April of 1634, probably the victim of anxiety over her father; he became blind in 1638; but remained productive almost until his death on January 8th 1642.
The nephews of Urban VIII had to flee the City at his death in 1644 in order to escape the wrath of the Roman mob.
[ii] Genesis 1; Numbers 16:30ff; Isaias 14:9 & 15.
[iii] Genesis 1; Psalm 18; Job 9; Josue 10.
[iv] Josue 10; Ecclesiastes 1
[v] Job 9 & 38.
[vi] Psalm 101: 26-27
[vii] Psalm 103: 5 & 6
[viii] From Peter Apian's Cosmographia, 1524
[ix] Catholic Encyclopedia (C.E.), s.v. St. Albertus Magnus (sec. IV), http://www.newadvent.org/cathen/01264a.htm
[x] Zupko, Jack, "John Buridan", The Stanford Encyclopedia of Philosophy (Winter 2003 Edition), Edward N. Zalta (ed.), http://plato.stanford.edu/archives/win2003/entries/buridan
[xi] Giorgio de Santillana, The Crime of Galileo, p. 125; James Brodrick, SJ, Galileo, p.115.
[xii] For an animated explanation of epicycles and deferents: http://csep10.phys.utk.edu/astr161/lect/retrograde/aristotle.html
[xiii] C.E., s.v. Giordano Bruno www.newadvent.org/cathen/03016a.htm
[xiv] Robert Cardinal Bellarmine to Galileo, in Brodrick, SJ, Galileo, p.108-9, citing A Favaro, Galileo e l’Inquisizione, p.68.
[xv] Memo of the Holy Office dated February 26th 1616 in their file on Galileo. Brodrick, ibid. 105-6.
[xvi] Santillana, ibid., p. 194 -198. Brodrick holds that Galileo received the imprimatur through “shifty practices,” but does not explain. p. 127.
[xvii] Brodrick, ibid. 128.
[xviii] Brodrick, ibid. 138.