Galileo and his Heliocentrism. It is one of the classic fables about science vs. religion that we have been hearing for ages. However, how much of it was really the truth and how much is just myth?
One day I stumbled upon a comprehensive analysis to the answer of this question, which presented facts contrary to the widely-known tale. Because the author had already made a great writing, I figured I’d just repost what he wrote.
Original writer: Tim O’Neill, an Atheist, Medievalist, Sceptic and amateur Historian
You can also find his blog here.
The Galileo Affair
Most people understand the trial of Galileo Galilei as a key example of religious bigotry clashing with the advance of science and the textbook case of “Medieval” ignorance and superstition being superseded by reason and science. In fact, the whole rather complex affair was not the black-and-white “science vs religion” fable of popular imagination and the positions of both Galileo and of the various churchmen involved were varied and complex. The popular conceptions of the Galileo Affair are marked by a number of myths:
1. “Galileo proved the earth went around the sun and not the other way around.”
Actually, he did not. Copernicus had proposed a heliocentric model 32 years before Galileo was born and scholars and astronomers had been discussing this model and others like it ever since details of Copernicus’ theory had been published in 1539. Copernicus’ model was one of several that were under discussion and the subject of debate in Galileo’s time; several of which were geocentric while several others were heliocentric. Galileo added to this debate via his observations using his telescope, particularly by his work on how the phases of Venus supported heliocentrism, but he did not “prove” heliocentrism at all.
This was because, as Galileo and all other astronomers of the time knew, there were several serious objections to heliocentrism which were, at that stage, hard to definitively dismiss. The lack of an observable stellar parallax was one and several problems involving the inertia caused by a revolving earth were another. Both were the reasons the ancient Greeks had rejected heliocentrism in the first place and neither were conclusively solved until long after Galileo’s death.
So while Galileo argued strongly for the Copernican model, he did not “prove” heliocentrism conclusively. He was also wrong about several key details – particularly the shape of planetary orbits (he rejected Kepler’s theory of elliptical orbits and clung to circular ones) and his idea that the tides were caused by the earth’s rotation. The idea that he proved heliocentrism is myth.
2. “The Church rejected science, condemned heliocentrism and was ignorant of the science behind Copernicus’ theory.”
This is also a myth. In fact, many of Galileo’s staunchest champions and defenders were churchmen and many of his attackers were fellow scientists. Centuries before Galileo the Catholic Church had rejected the idea that there was something wrong with the rational analysis of the physical world, accepting the argument that since God was rational, his creation was rational and so could be apprehended by rational inquiry. This paved the way for the acceptance of the rational analysis of the world by ancient Greek philosophers and so Plato, Aristotle, Archimedes and many other Greek thinkers were enshrined in Medieval thought, establishing “natural philosophy” (what we call “science”) in the universities of Medieval Europe and laying the foundations for the rise of modern science as we know it.
The Church was also quite open to the ideas of Copernicus. Copernicus himself was aware that there were several strong objections to his model, as noted above, and hesitated publishing his work as a result. But he was strongly encouraged by Bishop Giese of Culm and so initially circulated a summary of his ideas in 1530. This got him widespread attention and in 1533 Pope Clement VII asked Johann Widmanstadt to deliver a private lecture on Copernicus’ theories in the Vatican Gardens. He was so intrigued and delighted by the lecture that he rewarded Widmanstadt with the gift of a valuable manuscript.
Galileo himself was lauded and revered for his learning and the Jesuit Order, in particular, claimed him as one of their own, since he was Jesuit-educated. Initial objections to his telescopic observations were overturned when Jesuit astronomers of the Collegium Romanum made their own telescopes and repeated his results.
As noted above, by 1616 there were several competing cosmological models under discussion in scientific circles and, as some of the leading scholars of the day, churchmen were in the thick of these debates. None of these models was without its flaws or serious objections, but the science of the day tended to continue to favour geocentrism. Galileo’s position was actually in a minority amongst the scientists of the time and this was well understood by scientifically-literate churchmen. At this stage, however, heliocentrism was an entirely valid alternative idea and one thought worth consideration and study. It was not (yet) condemned, not suppressed and not declared heretical.
3. “The Church condemned heliocentrism because it believed the Bible had to be interpreted literally.”
The Catholic Church did not (and does not) teach that the Bible had to be interpreted literally. In fact, the idea of Biblical literalism is a very modern notion – one that arose in the USA in the Nineteenth Century and is exclusively a fundamentalist Protestant idea. The Catholic Church, then and now, taught that any given Bible verse or passage could be interpreted via no less than four levels of exegesis – the literal, the allegorical/symbolic, the moral and the eschatological. Of these, the literal meaning was generally regarded as the least important. This also meant that a verse of scripture could be interpreted via one or more of these levels and it could potentially have no literal meaning at all and be purely metaphorical or symbolic.
Therefore the Church had no problem with learning that a passage which had been interpreted literally could no longer be read that way because we now have a better understanding of the world. So many passages were originally interpreted by very early Christians as indicating the earth was flat, but by the time Christianity spread to more educated converts, it was clear this reading was contrary to the knowledge that the earth is actually a sphere, so these passages came to be read purely symbolically.
All this means that the Church was quite capable of changing its interpretations of scriptures that seemed to say the earth was “fixed” etc if it could be shown that this was not literally the case. It just was not going to do so before this was demonstrated conclusively – something Galileo had not done. As Cardinal Bellarmine noted in his 1616 ruling on Galileo’s writings:
If there were a true demonstration that the sun is at the centre 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. But this is not a thing to be done in haste,
and as for myself I shall not believe that there are such proofs until
they are shown to me.
Bellarmine was no scientific ignoramus, since he had previously been a university lecturer in natural philosophy in Flanders and was well acquainted with the state of the cosmological debate. So he knew, as Galileo knew, that most scientists of the time still favoured geocentrism and heliocentrism was far from proven. As it happens, once heliocentrism was proven, the Church reconsidered and reinterpreted those scriptures precisely as Bellarmine proposed they should.
4. “Galileo was imprisoned in chains, tortured and threatened with being burned at the stake.”
In November 2009 the comedian and actor Stephen Fry joined the late Christopher Hitchens in a televised debate with two Catholics on the question of whether the Catholic Church was “a force for good in the world.” Fry and Hitchens won the debate hands down, but at one point Fry referred passionately to “the fact that [Galileo] was tortured” by the Inquisition. In his book The End of Faith, Sam Harris seems to be trying to refer to Galileo when he talks of the Church “torturing scholars to the point of madness for merely speculating about the nature of the stars”. Voltaire famously wrote of how Galileo “groaned away his days in the dungeons of the Inquisition” and the idea that Galileo only backed down because of his (understandable) fear of being burnt at the stake is a mainstay of the fables about the Galileo Affair. All these ideas are nonsense.
In fact, far from groaning in any dungeons, Galileo spent all of his 1633 trial as the honoured guest of various senior churchmen in several luxurious palaces and apartments in Rome. Despite Fry’s passionate claim, he was never tortured nor was he in any genuine danger of being so, both on account of his age but also because of the willing and even enthusiastic way he co-operated with the inquiry (though his friendship with many key players in the Church would also have helped if there had been any genuine risk here). The accounts of his trial show that at no stage was he ever in any danger of execution – a punishment reserved for what were considered the most serious cases of unrepentant or relapsed heresy. And he did not live out his days in any “dungeons”. His final sentence was actually harsher than he and many others expected, but he was placed under house arrest in his villa in Florence for the remaining nine years of his life, where he completed several of his most important works before he died.
Of course, the idea of anyone being tried, condemned and placed under house arrest (even in a very comfortable villa in Tuscany) is objectionable to our modern sensibilities. But the fact remains that the ideas he was tortured, was in danger of being burnt at the stake, was imprisoned or lived out his days in some kind of dungeon are all myths.
5. Galileo was condemned simply for using science to question Church teachings, which was forbidden by the Church.
As noted above, the Church did not condemn scientific inquiry – in fact, most people at the time that we would call “scientists” (a term not used until 1833, when it was first coined by William Whewell) were also churchmen. And it was not even a problem for someone to show that a traditional interpretation of Scripture or a teaching of the Church had to be reinterpreted by reference to a new understanding of the physical world. The Church taught that divine revelation and the revelations of reason all came from the same ultimate source and so if they seemed to be in conflict, it was our understanding that was the problem. As quoted above, Cardinal Bellarmine noted to Galileo that if heliocentrism could be objectively demonstrated then the scriptures that seemed to support geocentrism should and would be reassessed. Though he added “but this is not a thing to be done in haste”. The problem was that Galileo and the minority of scholars who accepted heliocentrism at that stage had not objectively proven heliocentrism, since there were still several objections that they had not fully answered and which were not answered until long after Galileo’s death (the stellar parallax problem was not definitively answered until 1838).
After Bellarmine’s ruling in 1616 Galileo had to agree that he had not proven heliocentrism. He agreed not to present the Copernican model as objective fact, since he could not prove it to be such. He agreed only to explore it and teach it as a calculating device for astronomical purposes. In 1632 the Pope asked Galileo to write a book presenting both the Copernican and Ptolemaic models, with arguments as to the strengths and weaknesses of both. Galileo produced The Dialogue Concerning the Two World Systems, but did so in a way that made it clear he considered the Copernican model superior. He also put some of the arguments used by the Pope into the mouth of a character in his dialogue called “Simplicimo” – which in Italian meant “the fool”.
Angered by this, the Pope effectively withdrew his support for Galileo and allowed him to be tried by the Inquisition for breaking his agreement of 1616 in the way he argued in the Dialogue. The Inquisition found that he had and he was punished for this.
The Church had been already well on the way to taking account of and accepting the implications of the Copernican Revolution. Jesuit scholars in the Collegium Romanum were happily taking Galileo’s lead and using telescopic observations to support, critique or adjust Copernicus’ ideas and they and other Catholic scholars were engaging with astronomers across Europe, including Kepler and Brahe, in the debates about the various models under discussion at the time.
It was petty academic jealousy by other scientists that dragged Galileo’s work into the scrutiny of the Inquisition and it was the personalities involved and the politics of the time that meant this escalated into his condemnation and a condemnation of Copernicanism generally. Eventually this over-reaction was reversed, but it was in no way an inevitable Church reaction to what was happening in astronomy at the time. Things could easily have progressed so that the Church accepted heliocentrism without any condemnations or clashes over science at all.
The Galileo Affair was a complex series of events which involved a lot more than just science and religion. It was set against the backdrop of the aftermath of the Reformation and the Catholic Church’s aggressive attempts to shore up and reassert its authority. It was also bound up with the personalities involved: the rival scientists who started the suspicions about Galileo out of professional jealousy, the ambitious but scientifically illiterate preacher who fanned the flames, the sensitive Pope who felt snubbed and humiliated by one of Galileo’s books and Galileo himself, who could be arrogant and abrasive to the point where even his allies despaired.
A careful examination of the evidence shows that the modern fable that is most people’s understanding of the Affair bears little resemblance to historical fact. Fables make for nice, neat stories with cute morals at the end. But history is not neat and rarely fits into morality tales. True rationalists are interested in what actually happened and why, studied as objectively as possible, not cute stories. Many of my fellow atheists, especially the ones of the more outspoken variety, would do well to brush up their history when it comes to Galileo and to tread carefully when invoking this subject.
Ronald L. Numbers (ed.) Galileo Goes to Jail and Other Myths about Science and Religion (Harvard University Press: 2010)
Richard J. Blackwell, “Galileo Galilei” in Science and Religion: A Historical Introduction Gary B. Ferngren (ed.) (John Hopkins Press: 2002)
David C. Lindberg, “Galileo, the Church and the Cosmos” in When Science and Christianity Meet, D.C. Lindberg and R.L. Numbers (eds.) (University of Chicago Press: 2003)
William R. Shea & Mariano Artigas, Galileo in Rome: The Rise and Fall of a Troublesome Genius, (Oxford University Press: 2003)
Giorgio de Santillana, The Crime of Galileo (University of Chicago Press: 1955)
Maurice A. Finnocchiaro (ed.) The Essential Galileo, (Hackett Publishing: 2008)
Richard J. Olson, Science and Religion, 1450-1900: From Copernicus to Darwin, (John Hopkins Press: 2006)
James Hannam, The Genesis of Science: How the Christian Middle Ages Launched the Scientific Revolution (Regenery Publishing: 2011)