Science, Religion, and the Galileo Affair

 

by Jon Paul Sydnor

Is the relationship between science and religion characterized by struggle or agreement? There are countless models for this relationship, but they basically fall into two camps. They either argue that science and religion are in inevitable conflict, or that science and religion—understood properly—are distinct but complementary aspects of human culture.

For those who argue that science and religion must be in conflict, the most frequently cited evidence of such conflict is the Galileo affair. In the popular interpretation of this unfortunate event, the famous physicist, inventor and astronomer Galileo Galilei was sentenced by the Catholic Church to life under house arrest for claiming that the Earth revolved around the Sun. Church authorities also forced him to retract his heliocentric theory (centered on the sun) and promise not to promote it any further.

For conflict theorists who believe that science and religion are incompatible, this event provides one powerful example of the darkness of religion in relation to the brilliance of science. The only solution they propose is to reject all religious belief and usher in a new age of unfettered reason, scientific inquiry and technological advancement.

Unfortunately, the truth is not that simple. The study of history usually challenges casual assumptions about past events, and the Galileo affair is no exception. To come to a deeper understanding, let us consider this matter in all its political, cultural, historical, and theological complexity.

Galileo was not the first astronomer to claim that the Earth revolved around the Sun. This honor belongs to Nicholas Copernicus, a Catholic churchman with a doctorate in canon (ecclesiastical) law. Copernicus promoted heliocentrism in De revolutionibusorbiumcoelestium (On the Revolutions of the Celestial Spheres), which he dedicated to Pope Paul III. Copernicus' book was uncontroversial for several reasons. First it was an anti-realist (we can't know how things really are, but doesn't this heliocentric model simplify the math!) preface to Copernicus' book written by his Lutheran publisher Andreas Osiander. Osiander carefully argued that Copernicus' sun-centered astronomy did not describe the solar system as it really is; it just offered a theory of planetary motion that made physics much simpler and calendars more accurate. (This is one of the few times in history that a Lutheran saved a Catholic from trouble with the Vatican.)

Second, the book was requested by Pope Clement VII. Copernicus sat on his work for 30 years until a letter from the Pope convinced him to publish it. As a thank you, Copernicus dedicated his book to Pope Clement.

Third, once the book was published, it did not attract much attention. People just thought it was wrong. Copernicus incorporates a great hypothesis, but inadequately information to overcome the dug in, Earth-centered (geocentric), Ptolemaic framework. So his work was more or less disregarded.

Finally, Copernicus died a year after it was published in 1542. His heliocentrism may have angered some people, but he wasn't around to be angry with them.

Like Copernicus, Galileo probably could have published his sun-centered theory without being condemned, but personalities and events conspired against him. Copernicus had no convincing observational evidence to support his claims, only a more elegant mathematical model of planetary motion. But even his math was problematic because he assumed the planets traveled in circles rather than ellipses, as Kepler discovered decades later.

In addition to being a great physicist, Galileo was also a great engineer and inventor. His telescope upgrades allowed him to see things no human being had ever seen before, including, problematically, Jupiter's moons. Galileo now had observational evidence that not everything in the universe revolved around the Earth. Moreover, his calculations were somewhat more accurate than Copernicus' and considerably more accurate than geocentric astronomers. Galileo had better technology, better observations and better physics than Copernicus, which brought him much more attention.

Above all, Galileo was a scientific realist. That is, he not only claimed to have created a better mathematical model to explain the motion of the planets. He claimed to have discovered the way things were, the true nature of the solar system. Establishing the Sun as the center of the solar system was not only mathematically useful; The sun was indeed the center of the solar system. This claim caused considerable consternation in a culture steeped in Aristotelian physics, Ptolemaic astronomy, and biblical cosmology. Changing such a worldview without provoking conflict would require considerable political skill.

Galileo had no political skills. Politically he should be fine - the recently appointed Pope Urban VIII. he was a great admirer of Galileo for the discovery of sunspots, mountains on the lunar surface, and even moons around Jupiter. The Pope, a Renaissance man, appreciated Galileo's heliocentric speculations. In 1624, however, the Pope advised Galileo that he should offer such theories as just these—theories. According to the Pope, God could make the heavens work as he wished. We could observe them and speculate about their nature and create models that helped us predict the movements of the planets, but we could never deny God the freedom to move the spheres in any way he chose. In other words, Pope Urban was an anti-realist—mathematical models may work well or poorly, but they don't tell us much about how things actually are. In a final order, the Pope allowed Galileo to write about his heliocentric theory, but only if he presented it as one of many theories, including the old, Earth-centered Aristotelian/Ptolemaic theory.

Galileo agreed, but did not follow exactly the spirit of the agreement. In 1632, Galileo published his Dialogue Concerning the Two Major World Systems. He followed the convention of presenting the heliocentric view as one among many by including three debating figures—everyman, Aristotelian (geocentric), and Copernican (heliocentric). Unfortunately, Copernicus crushed Aristotelianism so much that the book has been interpreted as supporting the Copernican system over the Aristotelian-Ptolemaic system. To make matters worse, the Aristotelian was called Simplicio, a word resembling "simpleton" in both Italian and English. Worse than that, Simplicio offered the same anti-realist argument that Pope Urban offered. Not only did Galileo violate the spirit of his agreement with the Pope, but he also offended and alienated his most powerful admirer.

The timing couldn't be worse. During the Thirty Years' War the Pope had converted from France to Mexico and the Protestant Reformation was spreading, and the result of the struggle was the strengthening of the Vatican's conservative wing. The soil was not fertile for new, challenging ideas.

Despite these difficulties, the church's response to Galileo's heliocentric theory of the solar system was not monolithic. They have fans and opponents, and their efforts turn into a battle between rivals. Among those most opposed to his views were biblical literalists. Biblical literalists interpret scripture as literally as possible, according to the plain meaning of the text, rather than as poetry or metaphor. Biblical literalism is most strongly associated with 20th century American Protestant fundamentalism and has been generally rejected by the Roman Catholic Church. However, in the Galileo affair, some opponents of Galileo's theories used a literal interpretation of the Bible to argue against heliocentrism.

For example, literal interpretations of several biblical texts suggested that the Earth must be stationary and the Sun revolved around it. Psalm 93.1 says, "God made the world firm, that it should not be moved" (see also Psalm 96.10 and 1 Chronicles 16.30). Psalm 104.5 says: “The Lord established the earth on its foundations; it can never be moved." And Ecclesiastes 1.5 declares, "The sun rises and sets and returns to its place. If these passages are considered science rather than poetry, then the earth cannot revolve around the sun; the sun must revolve around the earth.

As a man of sincere faith, Galileo took a lot of time to argue that his theory was compatible with the Bible, arguing that the Bible teaches us about salvation, not the nature of the universe. Galileo quoted a contemporary, Cardinal Cesare Baronia, who supported astronomical investigations with the argument: "The Bible tells us how to go to heaven, not how the heavens go." Galileo also argued that scripture is not about "science" but about faith. Science and faith have different modes of discourse and different methods of argumentation. He was referring to Augustine's accommodationism—the belief that God only reveals to people what they can handle at that time in history.

Alas, coming up with theories of biblical interpretation was not very popular with the church at the time - Martin Luther did it, after all. To top it all off, Galileo wrote his book in the vernacular rather than Latin. . . which Martin Luther did. Galileo's imitation of Luther did not please the church authorities.

Adding to his problems, Galileo made some scientific errors in his work that compromised the strength of his arguments. He spilled a lot of ink, arguing that the Earth's rotation on its axis caused the tides, even though mariners had known for centuries that the tides were related to the lunar cycle, not the length of the day. Galileo also, in a rare demise of Aristotelianism, rejected Kepler's argument that the planets traveled in elliptical orbits around the Sun. Instead, Galileo insisted that the heavenly bodies would have to travel in perfect circular orbits. The location of the circular orbits messed up Galileo's equations a bit and forced him to reinvent his own physics. Because of these errors, even some fair-minded scientists had doubts about Galileo's proposals.

Galileo was tried by the Inquisition in 1633 and found guilty of contempt of the Church. His jurors also found him "vehemently suspected of heresy" and forced him to renounce his heliocentric theory. The Inquisition banned his book and placed him under house arrest for the rest of his life. He continued to practice and preach at home for nine years. He died in 1642. Within a hundred years the heliocentric theory of the solar system was accepted throughout Europe.

Clearly, this is an example of a conflict between science and religion, right? Yes it is. But strangely, it also serves as an example of harmony between science and religion. Galileo was Catholic all his life. And he was no political Catholic. In his personal writings, private correspondence, and daily life, Galileo displayed a sincere faith in God and a deep fascination with God's creation. He thoroughly knew the "two books", the book of scriptures and the book of nature. And he was able to reconcile his religious beliefs with his scientific research. In fact, he saw both as different expressions of his faith.

Additionally, there was a huge disagreement in the church about Galileo's theories. He had supporters and detractors. His arrogance made him enemies, especially among Jesuit astronomers. In an unusual protest, only seven of the ten judges in the trial voted to convict; three abstained. He was never actually convicted of heresy, only of disobedience. And technically he was disobedient. So in the persons of Galileo and his ecclesiastical admirers we see the harmony of science and religion, while in Galileo's difficulties with his critics we see the conflict between science and religion.

So should we adopt a conflict model or a harmony model with regard to the relationship between science and religion? The historical evidence is mixed—fundamentalist creationists reject evolution, while the Roman Catholic Church and mainstream Protestants accept it. Some atheist scientists insist that all religion is superstition, but faithful scientists advance research while embracing the sacred.

A historical study of the relationship between religion and science suggests that neither the conflict model nor the harmony model is sufficient. In some subcultures, there is a conflict between science and religion. In other subcultures they harmonize. They relate in different ways at different times according to the assumptions and preferences of the given culture. Maybe the best model for relationships is the complexity model. Science and religion can clash or harmonize depending on who is thinking, why they are doing it, when they are doing it and where they are doing it. The relationship between science and religion can be as varied as the human beings who consider it. But for those who celebrate faith and science, both Creator and Creature, Galileo himself can serve as an inspiration.