Galileo’s Life and Trial

“If scripture cannot err, certain of its interpreters and commentators can and do so in many ways.”  – Galileo

Major issues:  unassailable Greek astronomy, politics within the church and Italian academics, inability to measure stellar parallax, flawed interpretations of scripture (Joshua 10:12: stand still O sun;  Psalm 93:1: thou hast fixed the earth, immovable and firm), recent outburst of the Reformation, and more.


Galileo had strong suspicions the Sun was the center, but couldn’t prove it.  This wasn’t Science vs. Religion, but Heretic vs. Orthodoxy.

Great starting point in video below:

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Explanation of early Greek astronomy here.

These ideas didn’t change over night:

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Copernicus was a smart fellow.  But his ideas needed lots of work to refine.  The complete adoption of his theory didn’t occur for a few centuries, however.

A few quotes below (from The Galileo Controversy) to demonstrate that the Roman Catholic Church wasn’t opposed to Science or Copernicus.  In fact, interestingly, Protestant Martin Luther was opposed to Copernicus’ model:

“Nicolaus Copernicus dedicated his most famous work, On the Revolution of the Celestial Orbs, in which he gave an excellent account of heliocentricism, to Pope Paul III.

Copernicus entrusted this work to Andreas Osiander, a Lutheran clergyman who knew that Protestant reaction to it would be negative, since Martin Luther seemed to have condemned the new theory, and, as a result, the book would be condemned.”

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Interesting view:

“Anti-Catholics often cite the Galileo case as an example of the Church refusing to abandon outdated or incorrect teaching, and clinging to a “tradition.” They fail to realize that the judges who presided over Galileo’s case were not the only people who held to a geocentric view of the universe. It was the received view among scientists at the time.

Centuries earlier, Aristotle had refuted heliocentricism, and by Galileo’s time, nearly every major thinker subscribed to a geocentric view. Copernicus refrained from publishing his heliocentric theory for some time, not out of fear of censure from the Church but out of fear of ridicule from his colleagues.”

Image below is from his own writings.  Sol means sun.

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Brahe took careful measurements, but created a false model:

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A little more context with Brahe mentioned at the very bottom.  Scientists were not convinced by Galileo.  Parallax shifts will be discussed at length further below:

“Many people wrongly believe Galileo proved heliocentricism. He could not answer the strongest argument against it, which had been made nearly two thousand years earlier by Aristotle:

If heliocentrism were true, then there would be observable parallax shifts in the stars’ positions as the earth moved in its orbit around the sun.

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“However, given the technology of Galileo’s time, no such shifts in their positions could be observed. It would require more sensitive measuring equipment than was available in Galileo’s day to document the existence of these shifts, given the stars’ great distance.

Until then, the available evidence suggested that the stars were fixed in their positions relative to the earth, and, thus, that the earth and the stars were not moving in space—only the sun, moon, and planets were.”

From Wikipedia, “Stellar parallax”:

“Stellar parallax is so small (as to be unobservable until the 19th century) that its apparent absence was used as a scientific argument against heliocentrism during the modern age.

It is clear from Euclid‘s geometry that the effect would be undetectable if the stars were far enough away, but for various reasons such gigantic distances involved seemed entirely implausible: it was one of Tycho Brahe‘s principal objections to Copernican heliocentrism that in order for it to be compatible with the lack of observable stellar parallax, there would have to be an enormous and unlikely void between the orbit of Saturn and the eighth sphere (the fixed stars).

James Bradley first tried to measure stellar parallaxes in 1729. The stellar movement proved too insignificant for his telescope, but he instead discovered the aberration of light and the nutation of Earth’s axis, and catalogued 3222 stars.”

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Thus Galileo did not prove the theory by the Aristotelian standards of science in his day. In his Letter to the Grand Duchess Christina and other documents, Galileo claimed that the Copernican theory had the “sensible demonstrations” needed according to Aristotelian science, but most knew that such demonstrations were not yet forthcoming.

Most astronomers in that day were not convinced of the great distance of the stars that the Copernican theory required to account for the absence of observable parallax shifts. This is one of the main reasons why the respected astronomer Tycho Brahe refused to adopt Copernicus fully.”

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Kepler was an assistant to Brahe, and by studying Brahe’s calculations, made improvements to the solar model.  Kepler was a German Protestant, and was disappointed his fellow Protestants resisted his work.

“Ten years prior to Galileo, Johannes Kepler published a heliocentric work that expanded on Copernicus’ work. As a result, Kepler also found opposition among his fellow Protestants for his heliocentric views and found a welcome reception among some Jesuits who were known for their scientific achievements.”

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Along came Galileo around the time of Kepler.  Galileo’s greatest contributions arose from his much-improved telescope.

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This slide below highlights challenges Galileo faced.

Later videos will show that Galileo’s approach didn’t always help his relationship with the Church.    He was brash, outspoken, and lacked tact.

Also not mentioned in this slide is this fact:  the best parts of his theory — presented as fact when all the evidence wasn’t in — weren’t produced till his years under house arrest (long after his 2 trials).

This article — The Galileo Controversy — written by Catholic defenders, explains the Galileo controversy from their perspective.

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“Galileo could have safely proposed heliocentricism as a theory or a method to more simply account for the planets’ motions. His problem arose when he stopped proposing it as a scientific theory and began proclaiming it as truth, though there was no conclusive proof of it at the time.

Even so, Galileo would not have been in so much trouble if he had chosen to stay within the realm of science and out of the realm of theology. But, despite his friends’ warnings, he insisted on moving the debate onto theological grounds.

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In 1614, Galileo felt compelled to answer the charge that this “new science” was contrary to certain Scripture passages. His opponents pointed to Bible passages with statements like, “And the sun stood still, and the moon stayed . . .” (Josh. 10:13). This is not an isolated occurrence. Psalms 93 and 104 and Ecclesiastes 1:5 also speak of celestial motion and terrestrial stability.

A literalistic reading of these passages would have to be abandoned if the heliocentric theory were adopted. Yet this should not have posed a problem. As Augustine put it, “One does not read in the Gospel that the Lord said: ‘I will send you the Paraclete who will teach you about the course of the sun and moon.’ For he willed to make them Christians, not mathematicians.” Following Augustine’s example, Galileo urged caution in not interpreting these biblical statements too literally.”

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During this period, personal interpretation of Scripture was a sensitive subject. In the early 1600s, the Church had just been through the Reformation experience, and one of the chief quarrels with Protestants was over individual interpretation of the Bible.

Theologians were not prepared to entertain the heliocentric theory based on a layman’s interpretation. Yet Galileo insisted on moving the debate into a theological realm. There is little question that if Galileo had kept the discussion within the accepted boundaries of astronomy (i.e., predicting planetary motions) and had not claimed physical truth for the heliocentric theory, the issue would not have escalated to the point it did. After all, he had not proved the new theory beyond reasonable doubt.”


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The process to determine the sun was the center took many steps and generations of scientists to understand.  A Greek interpretation of scripture (see model above) was understood to mean the earth never moved.

Among other things, this video points out that we actually don’t revolve around the sun.  Instead, we revolve around the center of mass of the solar system.  The more complete picture — and we’re still learning all the time — took long after Galileo to see.

The Catholic Church didn’t accept the sun as center till 1758.  When Newton fully demonstrated this mathematically.

Galileo was extremely prolific.  His contributions to Science were enormous!

More details about the man:

Short video on the trial:

In additional to other expected details, this video explains that Galileo was brash and aggressive.  Galileo could have been more diplomatic and tactful.

The Pope requested before Galileo publish his findings, Galileo allow the Pope to contribute to the publication.  Galileo, instead, mocked what the Pope’s position was (earth at center).

This scholar shows that Galileo lacked evidence, according to other scientists of his own time.  Parallax and other arguments (earth didn’t appear to be flying through space) were against him.

He also mentions that Copernicus’ claims — 50 years before Galileo — wasn’t controversial.  But, by the time of Galileo, the Reformation had erupted.  The Church was worried about people interpreting scripture for himself.

This below video shares that scientists were divided in Galileo’s day.  Galileo himself didn’t have sufficient evidence to fully convince others and Church leaders.

Among some of Galileo’s bad ideas (of course, he had many good ones) was that the waves of the ocean were caused by the Earth’s rotation.  Galileo presented his research in Italian, not Latin.  That offended many.  Galileo mocked the Ptolemaic system (earth-centered) crowd of clergy and opposing scientists.  Galileo attacked fellow scientists, the clergy, and the Pope, despite not having sufficient evidence to prove his theory.

This video quotes a Catholic leader, Bishop Robert Bellarmine, who said that if evidence was presented the Church would change its interpretation.  But Galileo’s thesis lacked sufficient evidence.  He was teaching as fact what he couldn’t prove as fact.

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Bellarmine’s first explains the Church’s position:

“The Council [of Trent] prohibits interpreting Scripture against the common consensus of the Holy Fathers; and if Your Paternity wants to read not only the Holy Fathers, but also the modern commentaries on Genesis, the Psalms, Ecclesiastes, and Joshua, you will find all agreeing in the literal interpretation that the sun is in heaven and turns around the earth with great speed, and that the earth is very far from heaven and sits motionless at the center of the world.

Then illustrates the Church’s openness to new proof:

I say that if there were a true demonstration that the sun is at the center of the world and the earth in the third heaven, and that the sun does not circle the earth but the earth circles the sun, then one would have to proceed with great care in explaining the Scriptures that appear contrary, and say rather that we do not understand them, than that what is demonstrated is false.

If shown to this bishop he would believe, despite the evidence (especially of all appearances to him and contemporary scientists):

But I will not believe that there is such a demonstration, until it is shown me. Nor is it the same to demonstrate that by supposing the sun to be at the center and the earth in heaven one can save the appearances, and to demonstrate that in truth the sun is at the center and the earth in heaven; for I believe the first demonstration may be available, but I have very great doubts about the second, and in case of doubt one must not abandon the Holy Scripture as interpreted by the Holy Fathers.

Further, Galielo had agreed a decade earlier to not teach his theory as fact.  Finally, most of Galileo’s work that we celebrate today took place while he was in house arrest.

Usually, atheists today claim that the Galileo controversy was between Science and faith.  Not so simple.  This article — What were Galileo’s scientific and biblical conflicts with the Church? — points out:

“It was not a simple conflict between science and religion, as usually portrayed. Rather it was a conflict between Copernican science and Aristotelian science which had become Church tradition.”

Early Christian leaders found ways to absorb Greek philosophy and teachings into the scriptures.  Just as they did with other concepts, such as ex nihilo creation and God’s characteristics:  outside of space and time, immutable (not changing), impassible (no feeling or emotion), etc.  So, the same way the Trinity evolved from Greek philosophy, so did a earth-centered view of the Universe.

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“Aristotle (384-322 B.C.) believed the universe is finite and spherical with a stationary Earth at its center. Enclosing the whole universe is the sphere of the Prime Motion turned by the First Unmoved Mover. Inside that were transparent spheres containing fixed and unchanging stars, planets, moon and sun.[1] Aristotle was also a renowned philosopher.

Clement and Origen (185-254 A.D.), both of Alexandria, sought to reconcile Greek wisdom (Aristotle’s thoughts in philosophy and sciences) with scriptural wisdom. Origen imagined separate literal, moral, and spiritual senses of Bible passages (expanded to five senses in Concordism today).[2]

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Van Bebber says, “This allegorical interpretation gave birth to a new brand of Christianity. Augustine (354-430 A.D.), although not as extreme as Clement or Origen, accepted this new approach. Through Augustine the mixing of philosophy, culture, and theology became inter-twined. And, since Catholic theology recognizes the traditions of the Church as equal in authority with written scripture, changing this trend became impossible. Eventually, the roots planted in Augustine took full bloom in Thomas Aquinas” (1224-1274 A.D.).[3]

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The Renaissance Period (1300-1600 A.D.), the rebirth of Greek philosophy, reinforced Aristotle’s philosophy and science, already embedded in Roman Catholic theology and tradition. The most serious scientific error was acceptance of an Earth-centered cosmos. But this error fit well in the man-centered theme of the Renaissance.

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Nicholas Copernicus (1473-1543 A.D.) was a Renaissance man educated in the classics, law, theology, mathematics, metaphysics, languages, and astronomy. Copernicus developed a cosmology with the sun at the center, the Earth rotating about a polar axis, and the Earth and planets circling the sun, essentially as we know it today.[4]

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Galileo Galilei (1564-1642 A.D.) received a broad Renaissance education. Until 1610, when Galileo built his first telescope at age 46, he focused mainly on physics, not astronomy. He soon made discoveries which shook the foundations of the Aristotelian cosmos.

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He saw mountains, valleys and other features indicating change on the moon. He observed the motion of four of Jupiter’s moons, now referred to as the Galilean moons. No longer could scientists say that heavenly bodies revolve exclusively around the Earth. He also observed the phases of Venus, the only explanation of which is that Venus moves around the sun and not the Earth.”

The Church had assumed the truth of Aristotle’s cosmology was rock solid.  Nobody had better answers for nearly 2000 years.  Along come Copernicus and Galileo.  The article further explains:

“The primary problem, as introduced earlier, was that Aristotle’s science was going out of style; but the church was still attached to him. It could not make a distinction between Aristotle and Christian teachings; and in that era, there was no distinguishment or separation of science from philosophy. For the Church, if Aristotle was wrong, Christianity was wrong.[6]

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Another background factor in Galileo’s conflict with the Church was the influence of the Reformation. Because Martin Luther (1483-1546 A.D.) and the Protestant reformation (1517 A.D.) questioned Church authority, the Roman Church lost significant power and influence. It reacted with a list of literature forbidden to Catholics. Included were any writings challenging traditional Scripture interpretation.[7]”

Galileo believed in the Roman Church.  However, he thought their interpretation of scripture must be wrong.  He knew what he saw in the heavens.

“Excerpts from the letter to Madame Christina help to reveal Galileo’s view of Scripture and that of his predecessors. He writes, “I think in the first place that it is very pious to say and prudent to affirm that the Holy Bible can never speak untruth—whenever its true meaning is understood.”[10]

He cited Copernicus in the same vein: “He [Copernicus] did not ignore the Bible, but he knew very well that if his doctrine were proved, then it could not contradict the Scripture when they were rightly understood”.[11]

Galileo further quoted Augustine.  Augustine, centuries earlier, had shown that people often misinterpret what is in the Bible:

He quotes Augustine relating true reason to Scriptural truth.

“And in St. Augustine [in the seventh letter to Marcellinus] we read: ‘If anyone shall set the authority of Holy Writ against clear and manifest reason, he who does this knows not what he has undertaken; for he opposes to the truth not the meaning of the Bible, which is beyond his comprehension, but rather his own interpretation; not what is in the Bible, but what he has found in himself and imagines to be there’”[12]

The Church had no problem with these solid orthodox views. Galileo was a man of faith as well as science.

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Another issue mentioned earlier relates to stellar parallax.  Galileo got some of the Science right.  But was incapable, due to technology, to demonstrate all that Church leaders wanted to see to become fully convinced.

Parallax occurs during each revolution.  On one side of the sun (in July) stars appear in a certain position.  On the other side of the sun (in January) the stars appear in differing locations.

Nobody in Gaileo’s day understand that stars were billions of miles away.  If the sun were at the center, the Church and most scholars argued, why didn’t the stars appear to shift, as you’d expect if the Earth rotated around the sun?

So, partly because neither Galileo nor Copernicus could demonstrate parallax with stars — stellar parallax — the Church felt justified to retain the cosmology of Aristotle.

This video shows that stellar parallax wasn’t properly understood till 1838 when Bessel made the first parallax measurements.


Additional thoughts by this Catholic pamphlet on the controversy:

“It is a good thing that the Church did not rush to embrace Galileo’s views, because it turned out that his ideas were not entirely correct, either. Galileo believed that the sun was not just the fixed center of the solar system but the fixed center of the universe. We now know that the sun is not the center of the universe and that it does move—it simply orbits the center of the galaxy rather than the earth.

As more recent science has shown, both Galileo and his opponents were partly right and partly wrong. Galileo was right in asserting the mobility of the earth and wrong in asserting the immobility of the sun. His opponents were right in asserting the mobility of the sun and wrong in asserting the immobility of the earth.

Had the Catholic Church rushed to endorse Galileo’s views—and there were many in the Church who were quite favorable to them—the Church would have embraced what modern science has disproved.”

Another summary:

Those models failed the Scientific Method. Part of a model is to provide predictions on future observations. And a new model should provide better predictions that the current model. Copernicus and Galileo failed that test.

They both portrayed the planetary orbits as perfect circles. As such the predictions of planetary events were even worse than the geocentric model.

What Scientific journal today would even print any equivalently poor model, let alone claim that this new model is the only correct one.

It wasn’t until Kepler came up with the elliptical model that the predictions equaled that of the current model, and Newton provided the explanation for why the elliptical model would be the true one.

So yes, the Church acted correctly. Even down the extent that the Church had no problems with the heliocentric model, as long was it wasn’t presented as being definitive until it was proven by observational evidence to be so. Would any modern Science journal do anything different?

BTW, Kepler, a Lutheran , was given a teaching position at the Catholic University of Prague and an appointment as court mathematician to the Catholic Emperor Rudolph II.

Timeline of Galileo’s Life