The Dressing Down of Galileo

How popular myths are made.

The figure of Galileo Galilei looms large in the modern world, even though few people when asked, seem to know precisely what he discovered. What they do seem to know is that Galileo was persecuted—or even tortured—by religious authorities for his scientific discoveries. As David Mills, author of the best-selling book Atheist Universe proclaims, “Galileo, remember, was nearly put to death by the Church for constructing his telescope and discovering the moons of Jupiter.”¹ The reason for this ill-treatment, says Mills, is that “pre-Renaissance man lived during a period when superstition overshadowed rational thought, and when those who proposed scientific explanations were often tortured to death by religious authorities.”²

The problem with this story is that it is a false myth. The factual reality is much more complex and—in my opinion—more interesting. The historical truth is that Galileo was an ingenious—and devout—scientist who, throughout his life, sought to understand the motion on the Earth that he unveiled through his experiments and the starry heavens that he disclosed through his telescope, in light of the vision of Heaven that he embraced as a faithful believer in God the Creator.³

A Hero of Faith and Celebrity of Science 

When Galileo discovered the moons of Jupiter in 1610 he was not “nearly put to death by the Church.” Instead, the religious authorities literally threw him a party. When Galileo presented his discovery of mountains on the moon, the phases of Venus, and the moons of Jupiter, the Jesuit astronomer-priests of the Catholic Church first verified Galileo’s findings, and then they “lauded him openly for his wonderful discoveries.”⁴

When he visited Rome in 1611 the Vatican astronomers gave Galileo a “hero’s welcome” and held a feast in his honor. Galileo's telescopic discoveries were also enthusiastically endorsed by devout Lutheran astronomer Johannes Kepler, as well as the leading Vatican astronomer and Jesuit priest, Christopher Clavius. Clavius, one of the most respected mathematicians in Europe, “and the man who had devised the new Gregorian calendar put into place in 1582 by Pope Gregory XIII (and still in use today).”

Clavius wrote that “Galileo’s discoveries required a rethinking of the structure of the heavens.”⁵ With the Church’s full support, Galileo was then elected to the exclusive scientific society the Accademia dei Lincei, and he soon became a scientific celebrity, acclaimed by all. Cardinal Maffeo Barberini, who would become Pope Urban VIII, even wrote a Latin poem dedicated to Galileo—and the verses specifically celebrate his “incredible and marvelous discoveries” of the moons of Jupiter, the three bodies of Saturn, and the solar spots.⁶

The Accidental Astronomer

Although today Galileo is chiefly remembered as an astronomer, his primary area of scientific interest—and lasting impact—was the physics of motion. Galileo was a Professor of Mathematics at the universities of Pisa and Padua, and while he did give lectures on standard geometric astronomy, his experiments and most creative insights dealt with the motion of objects and in constructing an alternative physics to that of Aristotle. When Galileo heard of a Dutch invention that made distant objects appear closer, “he saw in it an instrument he might profitably manufacture” and built one for himself. ⁷

Galileo’s initial interest in the telescope can be ascribed to “his perennial need for money to support his family” and he capitalized on the novelty of the instrument in a number of ways.⁸ Nevertheless, in 1609, in what may be described as a fortuitous occurrence, Galileo turned his newly constructed telescope to the night skies and—as he beheld familiar celestial objects with his new eyes—made a number of spectacular discoveries. Galileo became an instant celebrity and “for several months Galileo was lionized in Rome by clergy and nobility alike with an enthusiasm that amazed even him.”⁹ These early observations—made before others were able to construct similar telescopes—would essentially constitute the entirety of his scientific contributions to the field of astronomy.¹⁰

Investigating God’s Works

Galileo’s most enduring scientific work was in the area of physics, known as mechanics, which investigates the motions of objects on the Earth. Dropping objects of different weights off the Leaning Tower of Pisa, Galileo discovered that the speed of a heavy object falling is not proportionate to its weight, as Aristotle had claimed. While his findings in mechanics that related to the laws of motion were “ferociously disputed” by fellow scientists and mathematicians who were part of the Aristotelian academic establishment, the Church was supportive of his work.

During his entire career, Galileo was a practicing and believing Christian who affirmed “that there could be no fundamental opposition between God’s words and His works,” and “throughout his life he functioned as the good Catholic he claimed to be.”¹¹ The Church funded Galileo’s research and the large salary Galileo enjoyed as court mathematician and philosopher came from ecclesiastical revenues. As a scientist who investigated God’s creation he “enjoyed the respect, trust, and protection of many high Church officials.”¹²

Later in his scientific career Galileo even received a papal pension, becoming “a cleric in the summer of 1630 to the extent of wearing a tonsure and reciting a daily office.”¹³ For all of his life Galileo “saw no conflict between the domains of scientific research and faith in God.” Instead, “he believed that study of the universe would promote greater understanding of the correct interpretation of the Scriptures.”¹⁴ 

The Real Scientific Issue at Hand

In Galileo’s day, the question of Ptolemaic Geocentrism versus Copernican Heliocentrism was a moot point. Thirty years after Copernicus published his Revolutions the Danish Lutheran astronomer Tycho Brahe made a series of observations that eventually led him to reject the Ptolemaic Geocentric model of the solar system that was based on the cosmology of Aristotle. Convinced by the common sense—and empirical—observation that the Earth is not moving, Tycho constructed an alternative model of the solar system which placed the Sun at the center of the orbits of Mercury, Venus, Mars, Jupiter, and Saturn, while the orbits of the Sun and the Moon revolved around a stationary Earth at the center of the cosmos.

According to his contemporaries, Tycho had “proven clearly…the fact that for Saturn, Jupiter, Mars, Venus, and Mercury the center of the earth is not their center.”¹⁵ This is why there was no controversy when Galileo spotted the phases of Venus and discovered the moons of Jupiter—because pretty much everyone at that point was either a heliocentric Copernican or a geo-heliocentric Tychonian. As Johannes Kepler wrote in the year 1600: “Today there is practically no one who would doubt what is common to the Copernican and Tychonic hypotheses, namely that the sun is the center of motion of the five planets.”¹⁶ Both systems were consistent with the best available astronomical data and the real issue at hand was whether there was any physical proof that the Earth actually moved. Galileo thought he had discovered such a proof—from the motion of the tides—but he was ultimately mistaken. 

Stubborn Pride and Confirmation Bias

The scientific argument that Galileo showcased as the centerpiece of his famous Dialog was that the ocean’s tides are caused by the movement of the Earth. Galileo originally wanted to title his great work Dialogue on the Tides, but Pope Urban, who was a friend, a fan, and scientific supporter of Galileo, suspected that Galileo’s “proof from the tides” was empirically mistaken. Thus the Pope suggested the title Dialogue Concerning the Two Chief World Systems of the World—Ptolemaic and Copernican to save Galileo from potential embarrassment among his scientific peers (just in case Galileo’s argument turned out to be wrong).¹⁷

According to Galileo scholar and historian Maurice Finocchiaro, “Urban VIII did not think Copernicanism to be a heresy or to have been declared a heresy by the Church.”¹⁸ And since no educated interlocutor still held to the Ptolemaic theory, the Pope suggested this as a safe sparring partner—as opposed to the Tychonic system, which had many able scientific defenders. Pope Urban also cautioned Galileo to include other arguments in his Dialogue—such as Johannes Kepler’s theory that the moon causes the tides—so that he didn’t overstate his scientific case in focusing on his argument from the tides. 

While the Pope urged caution, Galileo threw all recommendations of hesitation to the wind. Galileo ardently insisted on the factual truth of his theory, even though there were numerous unresolved scientific problems with his proof, and instead of heeding the Pope’s friendly advice, Galileo openly insulted him in the text of his magnum opus. The Pope, feeling personally betrayed and publicly humiliated, demanded a formal apology and orchestrated a “show trial” to this end.

During the course of these events, Galileo was treated in a manner that was never less than “unprecedentedly benign.”¹⁹ His sentence of “house arrest” was not strictly enforced—as he traveled freely to visit his daughter and others—and he would publish his most groundbreaking scientific work—Two New Sciences—after his trial.²⁰ As a victim of one of the first cases of scientific peer-review Galileo was never imprisoned or tortured, but he did have to suffer the humiliation of being publicly censured for insisting that he was scientifically right, when in fact he was wrong.

1. David Mills, Atheist Universe: The Thinking Person's Answer to Christian Fundamentalism (Ulysses Press, 2006), 48.

2.  Mills, Atheist Universe, 85.

3. David Sobel, Galileo’s Daughter: A Historical Memoir of Science, Faith, and Love (Bloomsbury, 2011).

4. James Hannam, God’s Philosophers: How the Medieval World Laid the Foundations of Modern Science (Icon Books, 2009), 319.

5. Lawrence Principe, The Scientific Revolution: A Very Short Introduction, (Oxford University Press, 2011), 59.

6.  Maffeo Barberini, (Urban VIII), Adulatio perniciosa (1620).

7. In his construction of telescopes for profit, Galileo acted “more as a tinkering engineer than an academic researcher. There is also good evidence that he never thoroughly grasped the principles behind the device. The unassuming Kepler, who did understand the theory of optics, was able to greatly improve on Galileo’s design, and it was the Keplerian model that was adopted for general use by astronomers during Galileo’s lifetime. Nevertheless, Galileo was first to capitalize on the device’s potential.” Wade Rowland, Galileo’s Mistake: A New Look at the Epic Confrontation Between Galileo and the Church (Skyhorse Publishing, 2012), 103.

8. In 1609 small telescopes were being sold as novelties in Paris, London, and several cities in Germany. During a visit to Venice in July of 1609 Galileo was told of the device. “He had been in the city to try to negotiate a salary increase. Galileo heard about the telescope, or from whom, is not known, but immediately on his return to Padua on August 3, he constructed one of his own with a 3x magnifying power and quickly improved on this with another of 8x. By August 21 he was back in Venice to invite the Senate of the republic to a demonstration of a telescope of his own making on the tower of St. Mark. Three days later Galileo gave his telescope to the city, along with a letter outlining how it worked. A grateful Senate, in an outburst of public largesse, doubled Galileo’s professorial salary to 1,000 florins a year. It was only after the increase had been promised that the politicians learned that telescopes had been available in several European centers for some time. They were not pleased. When Galileo received his revised teaching contract he found that while the promised raise was there, it would not take effect for another year, and it was formally stipulated that this was the last raise he would ever get.” Rowland, Galileo’s Mistake, 103.

9.  Rowland, Galileo’s Mistake, 25.

10. Beyond these initial findings, explains historian Wade Rowland, Galileo “made no lasting contribution to astronomical theory.” (Galileo’s Mistake) Throughout his entire scientific career, Galileo “was in the thrall of a stubborn conservatism” (rooted in a Platonic mathematical idealism) that blinded him from seeing the truth of Tycho Brahe’s discovery that the crystalline spheres were not solid and that comets were celestial bodies (Galileo insisted they were merely sublunar optical illusions), kept him from accepting Kepler’s idea that the planetary orbits were not perfectly circular but elliptical, and hindered him from acknowledging Kepler’s insight that a mysterious pulling force from the moon was largely responsible for the ocean tides. Galileo’s contemporary Johannes Kepler “far outshone him as a theorist, and there were others, including Jesuit astronomers, who were equally competent observers.” See Principe, Scientific Revolution, 61; And Rowland, Galileo’s Mistake, 23.

11.  John Heilbron, Galileo (Oxford: Oxford University Press, 2010), 364.

12. Maurice A. Finocchiaro, “The Copernican Revolution and the Galileo Affair,” in The Blackwell Companion to Science and Christianity, ed. J.B. Stump and A.G. Padgett (Chichester: Wiley, 2012), 18.

13.  Heilbron, Galileo, 299.

14. David L. Block and Kenneth C. Freeman, God and Galileo: What a 400-Year-Old Letter Teaches Us about Faith and Science (Crossway, 2019) 24.

15. Noah J. Efron and Menachem Fisch, “Astronomical Exegesis An Early Modern Jewish Interpretation of the Heavens,” in Science in Theistic Contexts: Cognitive Dimensions, Osiris 16, ed. John H. Brooke, M.J. Osler, J.M. Van der Meer (University of Chicago Press, 2001), 74.

16. Nicholas Jardine, The Birth of History and the Philosophy of Science: Kepler’s A Defense of Tycho against Ursus with Essays on its Provenance and Significance (Cambridge: Cambridge University Press, 1984), 147.

17. Stillman Drake, Essays on Galileo and the History and Philosophy of Science, ed. Noel M. Swerdlow and Trevor Harvey Levere (Toronto: University of Toronto Press, 1999), 163.

18. Maurice A. Finocchiaro, The Galileo Affair: A Documentary History, (University of California Press, 1989) 32.

19. Maurice A. Finocchiaro, “Myth 8 That Galileo Was Imprisoned and Tortured for Advocating Copernicanism,” Galileo Goes to Jail and Other Myths about Science and Religion, edited by Ronald L. Numbers, (Harvard University Press, 2010) 74.

20.  It is a myth that Galileo was afraid to publish his book in Italy for fear of the Inquisition and that he had to surreptitiously sneak it out of the country. As Maurice Finocchiaro says: “The manuscript of the Two New Sciences was not smuggled out of Italy by one of Galileo’s disciples.” Maurice A. Finocchiaro, Retrying Galileo, 1633-1992 (University of California Press, 2005), 301.