"The notion that Galileo's trial was a conflict between science and religion should be dead. Anyone who works seriously on Galileo doesn't accept that interpretation anymore." - Historian Thomas Mayer.
Galileo's trial before the Roman Inquisition in 1632-33 has long been used as an example of a scientist persecuted by religious zealotry. Those who promote the idea that science and religion are at enmity like to bring up Galileo's unfortunate treatment at the hands of the Roman Catholic Church. However, there is much more to the story than the neat and tidy picture of Galileo as a martyr for science and reason. Not only was Galileo himself a devout Catholic throughout his life, but his trial was far more about his insulting the Pope directly than it was about whether Earth actually moved around the Sun.
In 1632, the already famous astronomer Galileo Galilei published his Dialogue Concerning The Two Chief World Systems, a wildly popular book that launched Galileo into the hands of the Inquisition. To better understand that trial and the controversy surrounding it, however, a bit of background is appropriate.
Ptolemy and Copernicus:
About the year AD 150, the brilliant astronomer and mathematician Ptolemy published his famous work Almagest. Using Aristotle's physics (not the Bible), Ptolemy argued for a geocentric model of the universe. Ptolemy's Earth was immoveable, and the Sun and stars revolved around it. He had some mathematical barriers in the way, but he made use of complicated epicycles to make his geocentric model work.
Ptolemy's geocentric model reigned supreme in astronomy circles until the 16th century. In 1543, Copernicus published a thick, mathematical book called On The Revolutions Of The Heavenly Spheres, which made the case that the Earth and stars, in fact, revolved around a stationary Sun. He still depended on epicycles like Ptolemy, just a fewer number of them. Copernicus was not a pop science writer. His book was written for astronomers and not the general public, and so it didn't make many waves at the time.
According to surviving class notes, the young Galileo taught Ptolemaic astronomy to his students at the University of Pisa and later at the University of Padua just as the other scientists of his time did. He didn't know any better until 1608, when he got his hands on an elementary telescope – an "optic tube" as he called it. Galileo did not actually invent the telescope, but he devised one and modified it, and he used it with determination.
The Telescope Discoveries:
Galileo's instrument was a crude thing with a narrow field of view that only magnified celestial objects for him between 3x and 30x as he made improvements. Yet, in 1609, Galileo made eight important discoveries, many of which he published in his 1610 book Starry Messenger:
-Sun spots were part of the surface of the sun (contradicting Aristotle's idea that celestial bodies were perfect and changeless).
-The moon was not a smooth surface made of a celestial substance as Aristotle had taught but in fact had mountains and rough surfaces just like Earth.
-Venus had phases, just like the moon, which would make sense if it orbited the Sun (and not Earth).
-Saturn had "ears" - later discerned as its famous rings.
-Stars were more distant than planets.
-There were stars in the cosmos that were invisible to the naked eye.
-The Milky Way was made of stars.
-Jupiter had moons, and so Earth was not the sole center of the universe as the Aristotelians claimed.
These were fantastic discoveries. In his journal, Galileo wrote, "I render infinite thanks to God for being so kind as to make me alone the first observer of marvels kept hidden in obscurity for all previous centuries."
Galileo was not a particularly righteous and holy man. He had three children by a woman he never married, and while his ambition earned him a place with the most esteemed people of his day, his inflated ego eventually got him tangled up in court. At the same time, Galileo gave God constant credit for the greatness of His creative powers and glory. He marveled at God's power and the honor that had been given him in being able to see things which had, until then, hung beyond humanity's reach.
Galileo and the Scriptures:
Unlike Copernicus' Revolutions, Galileo's Starry Messenger sold widely and he quickly became famous. He was not hauled into Rome for his discoveries, but was in fact well received. He made a shrewd political move and named Jupiter's moons the "Medicean planets" after the Medici dukes of Tuscany. He was given the position as the duke's mathematician and philosopher, which freed him up to stop teaching and devote himself to researching and writing.
The Roman Catholic Church didn't have an official position on the orbiting habits of celestial bodies just yet. Galileo was warmly received in Rome after his book was published. The Jesuits welcomed him, and he had several friendly visits with the Pope.
As brilliant and driven as he was, Galileo made the error of developing a significant arrogance, and he had no difficulty humiliating those who disagreed with him. He had a great talent for satire, and he made quite a few enemies through his sardonic wit.
One morning at the palace during breakfast, the duke's mother, Princess Christina, the Grand Duchess of Tuscany, upset everything. She made a comment that the Bible said the earth stood still and the Sun moved, rather than the other way around. Galileo wrote the Grand Duchess a letter, explaining that he believed the Bible, interpreted correctly, would match up with science. He went on to offer his position that the Bible said so little about the heavens and their movement, that clearly God wasn't concerned with teaching astronomy through His Word, and it was not a salvation issue:
"Since the Holy Ghost did not intend to teach us whether heaven moves or stands still, whether its shape is spherical or like a discus or extended in a plane, nor whether the earth is located at its center or off to one side, then so much the less was it intended to settle for us any other conclusion of the same kind. And the motion or rest of the earth and the sun is so closely linked with the things just named, that without a determination of the one, neither side can be taken in the other matters. Now if the Holy Spirit has purposely neglected to teach us propositions of this sort as irrelevant to the highest goal (that is, to our salvation), how can anyone affirm that it is obligatory to take sides on them, and that one belief is required by faith, while the other side is erroneous?...I would say here something that was heard from an ecclesiastic of the most eminent degree: 'That the intention of the Holy Ghost is to teach us how one goes to heaven, not how heaven goes.'"
Galileo then declared he was able to offer an interpretation of Scripture in light of what his scientific discovery had showed him. He suggested, for instance, that when Joshua told the Sun to halt in the sky, that the Sun did indeed halt in its rotation, to which he believed the motion of the planets and moon were connected. When the Sun halted, so did the entire system, allowing the day to lengthen accordingly as the Scriptures said.
The First Trial:
This letter got Galileo into trouble. The Church had said at the Council of Trent, in response to the Reformation, that common people were not permitted to interpret scripture; that was the job of the Church hierarchy. As Galileo's letter to Princess Chrstina became public, Galileo's enemies pounced. His years of satire had ruffled too many feathers. They wrote to the Inquisition and demanded that he be investigated. The Pope asked the theologians to decide exactly what the scriptures said about the matter. Was the Sun the center of the world and immoveable, and did the Earth spin on its axis and revolve around the Sun?
In 1616 the Roman Catholic Church declared Ptolemy to be correct. The Pope had Galileo instructed not to teach the heliocentric theory of Copernicus and sent him home. The index of prohibited books banned all books that treated Copernicusism.
For 16 years, Galileo cleared away from the debate. Then, in 1632, Galileo published his famous Dialog Concerning the Two Chief World Systems. A new Pope was in Rome, Pope Urban VIII, a personal friend of Galileo, and Galileo kept him up on the progress of his new book.
When it was published, however, the Pope was in for a shock. The book, which became a best seller, was written as a discussion between three characters discussing the heliocentric versus geocentric models of the universe, and the character who supported the Ptolemaic position was named Simplicio – the "simpleton". Those who supported the Ptolemaic side were described as "imbeciles" "dumb idiots" and "people who are too stupid to recognize their own limitations." At one point, the Pope's own words were spoken by Simplicio, which did not please the proud Pope. The book was banned, which only increased its popularity among the delighted masses.
The Second Trial
Galileo had made a miscalculation. He was called before the Inquisition and asked whether he'd written the offending book and was asked whether in 1616 he had been given an injunction to not promote Copernicus. Galileo defended himself sloppily, saying that he presented both sides of the issue in his book, and he did not believe he had trespassed the terms of the 1616 precept. The trial focused on determining the exact wording of the 1616 injunction and whether Galileo had violated it.
In the end, Galileo claimed that his satire had actually been written to defend Ptolemy. He declared that he did not hold the opinion of Copernicus. The court did not buy it, and Galileo was sentenced to life in prison. Galileo could have been tortured and imprisoned and burned at the stake, and he was quite aware of these possibilities. Instead, the Pope intervened – having made his point – and 69-year-old Galileo was kept under house arrest (including the houses of wealthy friends).
At his trial, Galileo insisted, "My only error was in my ambition in trying to appear smarter than everybody else."
Interpretation and Church Power:
Galileo's trials were therefore not the pitting of religion against science, but about the Roman Catholic Church's desire to exert its power, about whether a common man was permitted to interpret the Bible outside of the official Church or insult those in authority. Galileo never rejected the Bible, but in fact repeatedly affirmed its true purpose and the intention of the Holy Spirit as true and good.
Galileo remained throughout his life dedicated to the God who created the Heavens and the Earth.
"When I consider what marvellous things men have understood," Galileo wrote, "what he has inquired into and contrived, I know only too clearly that the human mind is a work of God, and one of the most excellent." (Poupard, Cardinal Paul. Galileo Galilei,1983, p. 101.)