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Church vs. Science: Galileo

Updated: Feb 24, 2022

By Luke Lancaster

Galileo was a popular scientist from 1564 – 1642 AD and his name is frequently brought up by non-Catholics attempting to get some dirt on Catholicism. They will claim that Galileo was unjustly treated by the anti-scientific Catholic Church for his scientific beliefs about heliocentrism. For example, the French revolutionist Voltaire and the astronomer Carl Sagan said that Galileo was sent to the dungeons of the Inquisition because of his scientific views. This, many will claim, indicates the great divide between faith and science. However, this is a false view of history. Galileo was not simply arguing for heliocentrism. Various people before Galileo argued for heliocentrism and were not censored like Galileo. The reason the Church treated Galileo that way was because of a few reasons. #1. He dogmatically argued for helio-centrism when, at the time, it had not been verified - ignoring the evidence (at the time) to the contrary. #2. He dogmatically reinterpreted Scripture in the face of the Protestant Revolution. #3. He insulted the Pope repeatedly. These reasons were why Galileo was censored by the Church. He was not censored because he was advocating science.


The world believed for almost 2,000 years that the universe (planets, stars, etc.) travelled around the earth, popularly known as geo-centrism. The earth was the immovable center of the universe. It was a natural inference ever since Aristotle in the 4th century, BC, and probably even before that. For every day, humans would look up to the sky and see the sun rise and set, while the earth seemingly stood still. The stars in the sky would move, but we would not. To change this geo-centric belief would take a significant amount of evidence. Even various biblical passages seemed to suggest geo-centrism.

For example, “At that time Joshua...said...‘Sun, stand still at Gibeon, and moon, in the valley of Aijalon.’ And the sun stood still, and the moon stopped, until the nation took vengeance on their enemies...The sun stopped in the midst of heaven and did not hurry to set for about the whole day. There has been no day like it before or since, when the LORD heeded the voice of a man...” (Joshua 10:12-14).

Almost everybody in the Church assumed that this passage implied geo-centrism. That would change some time after Galileo, though, once helio-centrism was all but proved by stellar parallax. It would later become clear that passages like Joshua 10 were describing the sun in the way that it appeared to us. The sun appears to rise and set, but that is not cosmologically correct. It is the earth that moves in actuality.

When Galileo first came on the scene with his scientific discoveries, he had zero issues with the Church. He improved the existing telescope of the day, and promptly started making new discoveries in the sky. This prompted Jesuit churchmen at the Roman College (ex. Fr. Christopher Clavius) to read Galileo’s works and verify what he was seeing with their own telescopes. These Jesuits encouraged Galileo’s scientific work. Galileo was treated as a celebrity by Catholic churchmen. For example, his discovery that the planet Jupiter had four moons won him many praises. He even visited Rome a few times. These discoveries, though, prompted Galileo to postulate the theory that the sun, rather than the earth, was the immovable center of the universe. One of the reasons he suggested this was that Jupiter was a moving planet with moons, and since the earth had a moon, then the earth moved as well. This helio-centric theory was not new, for it had been postulated before, but Galileo was convicted that the model was beyond a doubt.

Previous Believers of Helio-Centrism without Censure by Catholicism

Some Catholic scientists believed that the sun was the center of the universe before Galileo ever came on the scene. For example, Nicolaus Copernicus had only a few decades before Galileo written a six volume helio-centrist work called, “On the Revolutions of the Celestial Spheres.” Copernicus even dedicated it to Pope Paul III and did not get in trouble with the Church. Johannes Kepler did the same thing right after Copernicus. Kepler was welcomed by Jesuit clergymen and the Church aided his research by giving him a microscope. Fr. Buridan in the 14th century also had said that the earth moved. The difference between these three believers in helio-centrism and Galileo was that Galileo did not say helio-centrism was a theory, but rather a fact. Yet, at the time, not all of the evidence verifiably pointed towards helio-centrism.

Helio-Centrism Not Proven Yet

A big question to helio-centrism was, if the earth moved around the sun, then why did the positions of the stars not move in a parallax? If the earth moved, then stars should be seen from different places on the earth’s course around the sun. That could not be answered during Galileo’s time, leaving helio-centrism at just a theory. It would be in the 1800's that stellar parallax would be discovered. Also, based on the available research, another theory was just a possible as helio-centrism, and was postulated by the astronomer Tycho Brahe. Brahe said that the earth and the sun were motionless, and that the universe revolved around both of them. Another point against helio-centrism was the fact that one of Galileo's arguments for the helio-centric theory turned out to be blatantly false. He had said that the movement of ocean tides was produced by the earth moving, when in fact, it later became true that it was the moon causing the movement of tides. Check out other evidence going against Galileo from this time period in the book, “Setting Aside All Authority: Giovanni Battista Riccioli and the Science against Copernicus in the Age of Galileo” by Dr. Christopher Graney. So, unfortunately, Galileo was not content at saying that helio-centrism was just a theory, and he asserted that it was proven. He even started reinterpreting Scripture to fit his theory.

First Censure by the Church

This prompted Cardinal Bellarmine, a chief leader in Rome, to meet with Galileo. Bellarmine said to Galileo in 1616 AD that his new interpretations of Scripture through a helio-centric lens could be true, but that there would need to be more evidence for helio-centrism before he could do that. St. Augustine in the 5th century had said in his Literal Commentary on Genesis that sometimes Scripture is figurative, such as the seven days of creation in Genesis 1. So, geo-centrist appearing passages like Joshua 10:12-14 could be interpreted figuratively, as Galileo said. However, since helio-centrism was not fully verified, but was only a theory, Bellarmine told Galileo not to dogmatically hold to and popularize such an opinion. For, Bellarmine said, the geo-centrist/helio-centrist mix model by astronomer Tycho Brahe was still a possibility. Bellarmine also told Galileo that if he popularized his new opinions on Scripture, then the Catholic faithful could doubt the inerrancy of Scripture. The people might think that Scripture gave a false view on the universe. Thus, Galileo was forbidden to deal with helio-centrism.

The Catholic Church, it should be remembered, was very sensitive to the issue of interpreting Scripture in the 17th century. It was still going through the controversy of Protestantism. Martin Luther had recently argued that each person had equal authority to interpret Scripture, known as Sola Scriptura. This unbiblical position took the teaching authority of “binding” and “loosing” away from the hierarchy of Catholicism, and resulted in the creation of numerous heretical sects. The Church responded to this mess at the Council of Trent, which had just finished when Galileo was born. That Council affirmed against Protestantism that only the hierarchy of the Catholic Church (such as at an ecumenical council – Acts 15) could authoritatively interpret Scripture. When Galileo started introducing new interpretations about Scripture relating to geo-centrism, the siren went off in the minds of Catholic clerics.

Galileo the Ridiculer

The censure on Galileo by the Church got more serious later due to Galileo's temperament. Galileo ridiculed multiple people throughout his life, and created enemies everywhere. For example, when he promulgated his theory in 1595 AD that the ocean tides moved because the earth moved, he stubbornly mocked Kepler’s theory that it was the moon that moved the tides. Yet Galileo’s theory about the tides turned out to be wrong. He did this same thing again with Kepler regarding the orbit of planets. Galileo also arrogantly insulted Fr. Horatio Grassi multiple times in his book “The Assayer” for his view that comets moved in orbit. Galileo called comets optical illusions. Yet it turned out that Galileo was wrong and Fr. Grassi’s views were closer to actuality. So, Galileo frequently did not have enough evidence to dogmatically push for his theories, and this was the case with helio-centrism as well.

Galileo's tendency to insult people even went so far as to attack the Pope, and that was where things heated up. But at first, Galileo's friend Pope Urban VIII in 1624 AD had encouraged Galileo to write a book giving both the arguments for and against helio-centrism. Helio-centrism was only a theory and was not verifiably true yet, so this was fine. The Pope was encouraging the advancement of science here, not silencing it. However, Galileo did not follow the Pope, and in 1632 AD he published a book pushing for helio-centrism again called “A Dialogue Concerning the Two Chief World Systems.” To make matters worse, Galileo put the words of the Pope into the character “Simplicius”, a simple-minded geo-centrist, in his book. The book humiliated the Pope just as Galileo had humiliated previous scientists.

2nd Censure

Galileo's insults towards the papacy was the last straw, and it caused the Catholic Inquisitional Tribunal to offer a (non-infallible) disciplinary censor over Galileo’s research into helio-centrism in 1633 AD. They forced him to renounce the Copernican theory and said that it was contrary to the Faith. This was not due to a desire to eliminate science, but was rather because, as Galileo himself said, he had made fun of the Pope (Galileo, Science and the Church, 1971, p. 134).

Galileo was sentenced to live under house-arrest in a luxurious place. As Alfred North Whitehead said, “Galileo suffered an honorable detention and a mild reproof.” Living under house arrest was not horrible, for the Pope actually went so far as to give him a servant! Science was not squelched either, for Galileo was still able to work on other scientific endeavors. In fact, his best work came about in physics after the helio-centrism censure called "The Discourse on the Two New Sciences." Galileo still got his pension as well and died peacefully. He was not excommunicated, placed in a dungeon, or tortured.

The Church should not have done this, and it has been humble about this reality. Two centuries after this, in 1820 AD, the disciplinary decision with Galileo was lifted by Pope Pius VII. More recently, Pope John Paul II apologized for this. It became clearer over time that geo-centrism was never a dogma of Divine Revelation, but rather was a question of natural Revelation (for science). Divine Revelation comes from God in Scripture and Tradition and is to be understood more deeply by the Church, whereas natural Revelation is contained in the created universe and is to be understood more deeply by science.


Galileo was an undisputed genius. His censure was unfortunate, but was not because Catholicism hated science. Cardinal Bellarmine in 1616 and the Pope in 1624 had told Galileo not to push his theory as a fact, for there was not enough evidence. Yet Galileo disobeyed, seemingly too prideful to consider this point. The evidence wasn’t fully there for helio-centrism during Galileo’s time, and the Church wisely recognized that. It would be 200 years after Galileo that the helio-centrism theory would be significantly aided through the discovery of stellar parallax. The story of Galileo does not show that the Church was against science, for the Jesuits of the Roman college were friends with Galileo, and the mathematicians of that college helped Galileo with his theory. The Vatican today has a scientific observatory older than the United States.

To learn more about Galileo, check out the book, “Galileo Revisited: The Galileo Affair in Context” by Dom Paschal Scotti and "Galileo in Rome: The Rise and Fall of a Troublesome Genius" by William Shea and Mariano Artigas.

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