Galileo was right, but so were his critics (2015)
strangenotions.com
strangenotions.com
* https://tofspot.blogspot.com/2013/10/the-great-ptolemaic-sma...
The fact that the Earth moves was not 'proven' (or more technically, had strong empirical evidence for that hypothesis) until 1806 when Giuseppi Calandrelli reported parallax in α-Lyrae. That's ~250 years after Copernicus, and ~150 after Galileo.
Note that by 1700 or so, everyone had switched to Kepler's model: not necessarily because they thought it was "right" (there was no empirical way to tell), but primarily because the math was much easier and it got correct results. There were actually seven models floating around during the 1600s:
* Heraclidean. Geo-heliocentric. Mercury and Venus circle the Sun; everything else circles the Earth.
* Ptolemaic. Geocentric, stationary Earth.
* Copernican. Heliocentric, pure circles with lots of epicycles.
* Gilbertian. Geocentric, rotating Earth. (proposed by William Gilbert in De magnete)
* Tychonic. Geo-heliocentric. Sun and Moon circle the Earth; everything else circles the Sun.
* Ursine. Tychonic, with rotating Earth.
* Keplerian. Heliocentric, with elliptical orbits.
Its arguments are “it was not proven then” and „Galileo wasn‘t skilful enough not to insult the pope.”
It also intentionally misleadingly avoids to show to the readers the actual papers and sentence made by inquisition which are preserved and completely disprove the quasi-arguments.
Over the course of 1500 years after Ptolemy's publication there were more accurate measurements, so Copernicus threw in more epicycles to have the model better match observations, but that's just another layer of indirection. But how are C's epicycles any less 'ad hoc' than P's?
They hardly look any different, at least to a layman:
* http://astro-andy.eu//img/the_solar_system_of_mlp_ptolemaic....
* https://casswww.ucsd.edu/archive/public/tutorial/images/hist...
Kepler published his defense of the Copernican system in 1596. He then published his first two laws in 1609 using Brahe's (pre-telescopic?) observations; the first patent for the telescope was in 1608. So even by then things were moving toward what 'reality' actually is.
More generally, I think that the 'Galileo affair' is portrayed as being a bigger deal than it actually was. I also think that people underestimate how much "politics" was a blood sport at that time.
That is argument for what exactly? That only "proves" that the layman can't understand something that is "hard". "Math is hard, lets go shopping" argument.
Galileo didn't have to simply "believe" Copernicus, he was physically the first man ever to see the moons of Jupiter with this own eyes, using the telescope he made with this own hands.
The mere existence of these moons was completely against the church doctrine, explicitly stated by the Inquisition in the official sentence with which he was sentenced:
"the above-mentioned Galileo, because of the things deduced in the trial and confessed by you as above, have rendered yourself according to this Holy Office vehemently suspected of heresy, namely of having held and believed a doctrine which is false and contrary to the divine and Holy Scripture: that the sun is the center of the world and does not move from east to west, and the earth moves and is not the center of the world, and that one may hold and defend as probable an opinion after it has been declared and defined contrary to Holy Scripture."
First off, you have to understand the intellectual background. Aristotelian physics dominated Europe at the time. Aristotle held the Earth to be separate from the heavens, with the heavens being the realm of perfect forms. All imperfect objects seek to move to the center of the Universe, which is the center of the Earth, while perfect objects move in circles in the heavens. This was the intellectual foundation of geocentrism.
Galileo was the first human in history to point a telescope at the sky, and what he saw fundamentally undermined Aristotelian physics. The Moon is not a perfect form: it has mountains, just like the Earth. Not everything revolves around the Earth: Jupiter has its own moons that orbit it. The Sun is also not perfect: it has spots. Galileo also did mechanical experiments that demonstrated the principle of inertia (Newton's first law), which further undermined Aristotelian physics. With Aristotelian physics out the window, the strong intellectual bias towards geocentrism was also gone. Until Galileo's telescopic observations, he himself had been a geocentrist, like most people.
If you then look at geocentrism and heliocentrism with fresh eyes, there are a lot of appealing aspects of heliocentrism.
* Geocentrism needs epicycles to explain even the most basic elements of planetary motion (retrograde motion). Heliocentrism already explains retrograde motion without any epicycles. Not only that, but heliocentrism correctly predicts exactly where (in relation to the Sun) retrograde motion occurs. In the geocentric model, retrograde motion could occur anywhere, but in the heliocentric model, it has to occur when planets are opposite the Sun, and lo and behold, that's exactly where it occurs.
* The Jovian system and the Earth-Moon system also suggest that small objects orbit larger objects, according to some as-of-yet (at Galileo's time) undiscovered principle. Why would the Sun (which was then known to be much larger than the Earth) orbit the Earth?
* The phases of Venus decisively rule out Ptolemy's model. In order to save geocentrism, you have to invent some weird geo-heliocentric hybrid model (Tycho's model). To many people, a pure heliocentric model was much more appealing, and the hybrid model appeared to be an awkward attempt to save some of geocentrism.
Evidence that humans, while excellent problem solvers suffer terribly at the creative aspect. In far too many disciplines only by already 'knowing' something can we solve for it. The real miracle is that we're here at this level at all.
Compared to what baseline animal?
The author claims:
"the reaction at the time was "WTF? Which heresy are you talking about here?"
But the exact heresy was explicitly and very clearly stated both in the sentence by the Inquisition:
https://hti.osu.edu/sites/hti.osu.edu/files/documents_in_the...
"the above-mentioned Galileo, because of the things deduced in the trial and confessed by you as above, have rendered yourself according to this Holy Office vehemently suspected of heresy, namely of having held and believed a doctrine which is false and contrary to the divine and Holy Scripture: that the sun is the center of the world and does not move from east to west, and the earth moves and is not the center of the world, and that one may hold and defend as probable an opinion after it has been declared and defined contrary to Holy Scripture."
And in Galileo's Abjuration:
http://www.creatinghistory.com/galileo-galileis-abjuration-2...
"after having been judicially instructed with injunction by the Holy Office to abandon completely the false opinion that the sun is the center of the world and does not move and the earth is not the center of the world and moves, and not to hold defend, or teach this false doctrine in any way whatever, orally or in writing; and after having been notified that this doctrine is contrary to Holy Scripture; I wrote and published a book in which I treat of this already condemned doctrine and adduce very effective reasons in its favor, without refuting them in any way."
The premise of the whole "4 hour" series by that author is also wrong, approximately, that because the parallax of the stars wasn't observed until around 1750 Galileo "couldn't prove" in 1633 that the Earth is not standing still, therefore the Church was "right" and it wasn't a matter of faith but "a personal thing." It's obviously a completely invalid argument. Because the reason why Galileo was convinced about the wrongness of the heliocentric theory was the simple fact that he was really the first human in the world who saw the moons around other planet, not accidentally called "Galilean moons":
https://en.wikipedia.org/wiki/Galilean_moons
He didn't have to "prove." He was really sentenced only for "having held and believed a doctrine which is false and contrary to the divine and Holy Scripture." It's explicitly stated in the official document.
That something like that is a reason enough for a condemnation by the religious authorities, even in much more recent times, can be obvious to anybody who tried to read the source text of the condemnation to murder of the author "along with all the editors and publishers aware of its content" of the book "The Satanic Verses" in 1989. I won't link to that, intentionally, but there's enough details to... check the original sources!
Additionally, not only Galileo's but the Copernicus' book too remained banned by the Church for the next 200 years after Galileo was sentenced, in spite of all the scientific discoveries in these 200 years that made these texts less unique. And the discoveries... there were many of them. Starting with the publication of Newton's "Principia" in 1687, only 50 years after the sentence. Newton was, of course, out of the reach of the Catholic Church, thanks to the lucky coincidence of him being born in "a political system found on the family values of Henry VIII."
It's always more worth checking the original sources instead of believing in 4 hours of text of somebody who intentionally avoids quoting and discussing these very sources. A lot of false claims can be constructed by omitting the evidence, the original sources and inventing the interpretations of the actual events. It's a very dishonest approach and should not be supported.
The first time I went there, the Jesuit who was accompanying me told me that Galileo had visited this place, and that the story of church vs. science that we've all learnt in school was very simplified. Apparently Riccioli defended a hybrid geo-heliocentric model (due to Tycho Brahe) where the earth is at the center of the universe, the sun and moon revolve around it, but all the other planets revolve around the sun. We now know neither the sun, nor the earth is at the center of the universe, so both models were equally wrong, however according to my Jesuit guide, Riccioli's point of view was the only one that would have been both theologically acceptable and scientifically sound.
I guess what is really wrong about the classical story of Galileo's trial is that the catholic church is not and never was a monolithic entity: there are factions, dissent, political agendas.
If you're interested in further reading on Riccioli the Wikipedia page is very detailed:
https://en.wikipedia.org/wiki/Giovanni_Battista_Riccioli#Arg...
The observatory was later moved to Castle Gandolfo:
* https://en.wikipedia.org/wiki/Vatican_Observatory
After the light pollution got too bad, its use was retired, and now things are run out of Arizona:
* https://en.wikipedia.org/wiki/Vatican_Advanced_Technology_Te...
The head dude is Brother Guy, and he has some interesting interviews if you search for him:
The Pope's Space Rocks
https://www.youtube.com/watch?v=5OI4wb2XIZc
The Pope's Telescopes - Deep Sky Videos
https://www.youtube.com/watch?v=ccoGKAL6Qas
The Pope's Astronomer - Sixty Symbols
But for the record - Galileo could be arguing that the earth revolves around his ass and the Church would still be damnable for persecuting him or anyone else and "critics" is not the word one uses for anyone wielding arrest and execution powers to enforce a monopoly on science and thought in general.
Yes there was lack of observable star parallax. But XVII measurement precision was so, so much worse than the one required to detect parallax (15" was best precision achieved at the time vs <1" required to tentatively detect parallax and ~0.3" required to be sure about it), that stars could "be" 50x closer than they really are, and 50x smaller, and the world would still "fit" the observations if one assumes that parallax is just tad small enough to escape detection. Which means, nearly every star being much smaller than Sun. Such a small star is impossible, but since source of the stellar energy wasn't known anyway, that couldn't be determined.
"The most devastating argument against the Copernican universe was the star size problem. When we look at a star in the sky, it appears to have a small, fixed width. Knowing this width and the distance to the star, simple geometry reveals how big the star is (right). In geocentric models of the universe, the stars lie just beyond the planets, implying that star sizes are comparable to that of the sun (below). But Copernicus's heliocentric theory demands that the stars be extremely far away. This in turn implies that they should be absurdly large—hundreds of times bigger than the sun (bottom). Copernicans could not explain away the anomalous data without appeals to divine intervention. In reality, the stars are far away, but their apparent width is an illusion, an artifact of the way light behaves as it enters a pupil or telescope—behavior that scientists would not understand for another 200 years."
Also let's see, so a typical telescope aperture of the era have been 25-30mm (bigger will make focal ratio too big and chromatism totally unacceptable), which means Airy disk 5" big, or 1/40000 of the distance. Assuming stars being 1/15 parsec away to make their parallax just barely unobservable, it means yeah, stars 25x the size of Sun, which is whole lot and isn't a reasonable assumption.
But measuring Airy disk size is easy by using a hair put in the focal plane to see how quickly it crosses (will be 1/2 vs 1/4 of a second)... Easy experiment to check that Airy disk isn't a "star".
- Procyon has the same diameter and brightness as Saturn.
- If Procyon is much farther than (say) 100 times Saturn’s distance, simple geometry proves its actual size would dwarf the sun.
- All the stars would dwarf the Sun, which would then be the only pea in a universe of melons, which is absurd.
- But if Procyon were any closer, there would be visible parallax from the Earth's revolution.
- There is no visible parallax.
- Lack of parallax plus the apparent size of the stars therefore requires a stationary Earth. QED.
The problem with heliocentrism is that it requires a lot of additional hypothesis that are not needed by other (better performing !) models.
How could he possibly that have determined? I don't think that Brahe could measure this he hadn't even a telescope. The apparent diameter you see from stars is diffraction limited.
1. Why do some planets undergo retrograde motion, while others don't?
2. Why does retrograde motion only occur when a planet is opposite the Sun?
3. Why is there retrograde motion at all?
4. Why is it that we always observe smaller objects orbiting larger objects? (the Moon orbits the Earth, Jupiter's moons orbit Jupiter, implying that the Earth probably also orbits the Sun)
5. What are the orbital distances of the planets? This is completely undermined in the geocentric system, but very tightly constrained in the heliocentric system! In a geocentric world, there's no reason why it should be possible to even create a reasonably fitting heliocentric model. The opposite is not true.
Different oservations of apparent angular diameters were wildly inconsistent at the time of Galileo. It's natural that he would give less credence to an argument based on such shaky observations, and more credence to the many types of observations that favored heliocentrism.
Beyond these observations, there was a more general consideration. The geocentric model had been based on a view of the Universe that held the Earth to be fundamentally different from the heavens. Galileo's observations (of mountains and craters on the Moon and of sunspots, for example) showed that the heavens were actually very much like the Earth. The heavens were not a separate realm of perfect forms. They were made up of real worlds with their own landscapes and imperfections. Putting the Earth at the center of that Universe seemed absurd, whereas it hadn't before.
> Graney suggested in 2008 that Galileo's observations of stars were actually diffraction patterns called Airy disks
[1] https://www.nature.com/news/2010/100305/full/news.2010.105.h...
[2] https://link.springer.com/article/10.1007/s00016-007-0345-3
There can be no reason which results from such exercises as apologism ammounts to justifying travesties to assuage their own cognitive dissonance and deserver bad reputations. It fundamentally a perpetuation of the evils of the past through rationalization.
[0]: https://tofspot.blogspot.com/2013/10/the-great-ptolemaic-sma...
I think that might border on victim blaming. The Church had the power to persecute intellectuals who they felt were running too far, but that doesn't mean they had any rightful authority. If an illegitimate power is running around your society trying to get people to cow down to it, anyone who stands up to them by failing to cow down appropriately should be described as "heroic" moreso than "reckless." If nobody had ever stood up to the illegitimate authority, they would still be running things and imprisoning people for insulting them today. We are in great debt to everyone who was reckless in 1610.
Yes, vigorous scientific debate with arguments on both sides, as for example the argument of the Inquisition that heliocentricism was heresy.
An argument that the Inquisition certainly defended vigorously. Galileo was tried and found guilty of heresy, forced to recant his heretic views and spent the latter period of his life under house arrest.
It seems the way the scientific process works has changed since Galileo's arrest. We don't expect scientists who voice controversial opinions (i.e. ones that go against the accepted consensus) to be arrested, tried and imprisoned, for voicing such opinions.
Looking purely at the scientific case the bizarre world of epicycles seems like a vastly greater sin than star size or an entirely misunderstood Coriolis Effect that Riccioli posited but failed to calculate or measure correctly. I would go so far as to suggest that a stationary earth might seem intuitively obvious to a illiterate savage but anyone with a mathematical mind and access to a telescope ought to have figured out that stasis isn't the natural state of anything in the universe.
One might suggest that he author started from a place of wanting to present the Church he cares very much for in a better light and presented the best possible defense for its misbehavior. The best that can be said for him is that like a good attorney he believes in his client and defends him honestly. This doesn't make him correct. Science is the process of arriving at increasingly accurate models of reality by finding ways to test theories. This is inherently at odds with religion which is the process by which priests interpose themselves between man and god to derive status and importance by serving as the only valid conduit between man and both imaginary spiritual goods like salvation and the temporal goods they acquired by selling the former.
This is a problem when the shtick you have been selling everyone is universal truth because constantly having to revise it to be more in line with secular ideas makes it increasingly clear it was far from universal and once its clear that its just your best effort and not a very good one at that the long term viability of your mission is in doubt.
How long did you map them? My understanding is that to see the "odd cycles and misbehavior" you need to make observations over the course of months at the right time of year.
I understand that the explanation of this surprising result is related to harmonic analysis, such as Fourier series - the evolution of any periodic process in time can be just as correctly represented by a collection of harmonics of the correct amplitude and phase.
This does not, however, seem to lead one to gravity, while Kepler's laws do. One thing that Newton showed is that epicycles are unnecessary as part of an explanation of planetary motion.
If you were to apply the epicyclic model with sufficient precision to show the gravitational effects between the planets, I would guess you would have to include, for any one planet, epicycles with frequencies that are harmonics of the other planets' orbits. Without a theory of gravity, there is no obvious reason why that should be so.
Someone needs to make a Netflix special about this to set the plebes straight. And I include myself in that grouping!
Mental health trigger warning: this might unintentionally make an atheist believe in God and Jesus. If you have a background with religious trauma, avoid this post. It is weird stuff.
Ok, that said, the first point to make is that "God the father", in early and orthodox Christianity, wasn't a person, except as an allegory. The One God was rather the incomprehensible concept of Oneness -- more akin to a mathematical singularity than Zeus. This was discussed extensively by Philo of Alexandria (b.25 BC), one of the biggest influences on early Christians. That Oneness was also described by Plato and the Pythagoreans.
Pausing there -- I find this Oneness concept to be a really fascinating idea, especially as we now accept that the entire universe was born out of a single point in the big bang. Also, Oneness is more or less a culturally universal phenomenon in mystical and psychedelic experiences. This god of Oneness is a very different perspective than the "guy in the sky" perspective -- but it is actually still compatible with Christian orthodoxy.
Where does Jesus fit in? Jesus was the "Logos" -- translated poorly as "the word" -- which was understood by the contemporary stoics and jewish-greek philosophers (Philo) as "the eternal emanation of the Oneness". We need the logos as the oneness is really kind of boring with no diversity.
So, Jesus was viewed as the allegorical "son" of the oneness (the father). That's why Jesus was there since the beginning of time. But, the mystery of the Christian faith is that the cosmic logos incarnated as a human -- the Jesus story is the story of the logos becoming flesh. Make sense?
What troubled me was the Christian idea that you have to believe in Jesus to have eternal life. I found that irritating and disturbing. Why would belief in Jesus give eternal life?? Here is my best-faith interpretation: if you believe that we are all part of an eternal, common, cosmic logos, like if you really believe that we are the logos, then of course we don't die, we live on for ever, since we are the logos. So, in shorthand, believe in Jesus and you live for ever.
Of course, theology got weird when people wanted the allegorical stories to be true and adopted the absurd idea of biblical literalism. For instance, Theophilus was a 4th century Alexandrian pope who first wrote a treatise on why it was foolish to believe that the One god was a material person -- but then had to backtrack when the monks literally started rioting in the streets [1].
So, there you have it: orthodox christianity can be galactic in scope, philosophically sound and compatible with empirical physics. No supernatural required, but plenty of mystery.
[1] https://books.google.nl/books?id=9joABAAAQBAJ&lpg=PA37&ots=x...
I can't read the rest of the article because my eyes have rolled all the way to the back of my head.
But I read it anyway. Your warning was for naught since the post makes very little sense.
It defines God as literally everything, and Jesus as a vague notion of communication, thus if you believe in communication you can live forever. Somehow this is compatible with orthodox Christian teachings, just because the author says so. This is like when Unitarians call themselves "true Christians".
I didn't say the christian God is everything. I said the Christian God is the Oneness. That is not the all. It is the One. Perfectly one. Understanding the idea of Oneness is, well, not easy. Plotinus thought it could only be experienced, not verbally communicated.
And wait, Jesus as communication? No, I didn't say that, I said that Jesus is the logos, the emanation from perfect oneness.
I admit that proving orthodoxy is a challenge, since it has to be declared heresy first. But is hasn't been -- and these are old ideas. For instance, here is Paul, 8 Corinthians.
"there is no God but one.
5 For though there be that are called gods, whether in heaven or on earth; as there are gods many, and lords many;
6 yet to us there is one God, the Father, of whom are all things, and we unto him; and one Lord, Jesus Christ, through whom are all things, and we through him."
I read that as "the act of a medium propagating a message through itself." How air carries sound.
God is a trumpet, and Jesus air, and together sound coming out and absorbed elsewhere. Jesus is the process through which a message moves. A vessel.
>if you really believe that we are the logos
Sounds like we are the consciousness of the universe observing and experiencing itself. Are you saying Jesus was different, or we are all equally Jesus? Why do we have to believe we are the vessel through which the oneness communicates her message, to be the vessel through which the oneness communicates its message. Is a boat not a boat if it doesnt believe its a boat?
But I think I get what you are trying to say. Its the same as a cell in my body saying it will live forever, even if the cell dies off the body continues to live. We are cells in the logos, and even if the individual cells cease, the being continues. I dont think thats what people really want to hear when they are told "THEY can live forever." It also sounds like encouraging or needing ego death to really absorb/grok.
> Proposition to be assessed:
> (1) The sun is the center of the world and completely devoid of local motion.
> Assessement: All said that this proposition is foolish and absurd in philosophy, and formally heretical since it explicitly contradicts many places the sense of Holy Scripture, according to the literal meaning of the words and according to the common interpretation and understanding of the Holy Fathers and the doctors of theology.
> (2) The earth is not the center of the world, nor motionless, but it moves as a whole and also with diurnal motion.
> Assessment: All said that this proposition receives the same judgement in philosophy and that in regard to theological truth it is at least errouneous in faith.
The Church wasn't calling for scientific rigor. It was calling for adherence to orthodoxy - in this case, its interpretation of Scripture.
Graney and others make an ahistorical argument: they cherry-pick one observation (the apparent angular diameter of stars), and then apply modern arguments not known to people at the time (the actual size of stars) to say that Galileo's scientific argument was weak. They ignore all the other observations that strongly favored heliocentrism at the time (the phases of Venus, the discovery that Jupiter and its moons form their own Copernican system, the greater parsimony of the heliocentric system when it comes to explaining things like retrograde motion of planets, and so on), and focus on the argument about sizes of stars. But Galileo had a perfectly reasonable answer to the star-size argument: the stars might be very large, and different measurements of stellar angular diameters were inconsistent with one another. Countering with modern knowledge about the true sizes of stars doesn't give any insight into who had the stronger argument in the early 1600s.
On balance, the argument for heliocentrism was already much stronger at the time. And of course, forcing Galileo, under threat of torture, to publicly accept the Church's interpretation of Scripture did nothing to aid science.
This paper[1] points out that the "proposition is foolish and absurd in philosophy" is denouncing its scientific rigor. Of course they are also pissed at him for reinterpreting Bible verses, that is how the church got involved in the mess first place.
> and formally heretical since it explicitly contradicts many places the sense of Holy Scripture
The paper that you cite, claiming that the "proposition is foolish and absurd in philosophy" refers to scientific rigor, is written by the same person who gave the interview OP linked (Graney). With all due respect to Graney, his arguments about Galileo come across as anachronistic apologia, trying to interpret the early-17th-Century Church as being interested in scientific rigor, rather than orthodoxy.
Recall that the Galileo Affair occurred during the Counter-Reformation, a time when the Church was reeling due to the spread of Protestantism and was obsessed with orthodoxy and stamping out heresy.
If you want a more neutral and historically accurate depiction of the Galileo Affair, read Maurice Finocchiaro's writings.
That is one of the authors he cites on the scientific rigor bit.
More broadly, it's a classic case of parsimony vs empirical coverage. Galileo's model did not enable better predictions, in the short term. Parsimony arguments are always more persuasive in retrospect, when we know that the theory in question is correct. There are many parsimonious but wrong theories. It was not unreasonable at the time to think that Galielo's theory might have been one of them.
>then apply modern arguments not known to people at the time (the actual size of stars) to say that Galileo's scientific argument was weak
I think you're misreading the argument. They point out that Galileo's theory appeared to require all other stars to be much bigger than the Sun, which seemed implausible at the time. This point was made by Galileo's contemporaries, so it can't be anachronistic.
That's the same issue - the size argument. Without the argument about the sizes of stars, not observing parallax is not a problem at all. One can simply say that stars are far away.
> Galileo's model did not enable better predictions, in the short term.
Galileo did not have a model. He advocated Copernicus' heliocentric model, though I think his general attachment was more to heliocentrism than any particular heliocentric model (he appears not to have been particularly aware of Kepler's model).
> They point out that Galileo's theory appeared to require all other stars to be much bigger than the Sun, which seemed implausible at the time. This point was made by Galileo's contemporaries, so it can't be anachronistic.
Galileo measured much smaller stellar angular diameters than Tycho had, which very much called into question the reliability of the measurements. Arguing, based on modern knowledge, that stars are not so large, and insisting that this is the decisive argument, does come across as anachronistic to me. At the time, there were many other arguments in favor of heliocentrism that were very quickly accepted by a large part of the scientific community (particularly in Protestant Europe, beyond the control of the Church). Heliocentrism was widely accepted long before the star size objection was definitively answered (by an understanding of diffraction), and hundreds of years before the measurement of parallax. It was widely accepted even before a proper theory of gravity had been developed.
The star size objection clearly isn't anachronistic because it was considered to be a serious objection by other scientists at the time, on purely scientific grounds.
Not by most scientists, who adopted heliocentrism long before diffraction was understood.
And again, the opposition from the Church was due to theological and political reasons.
What's your source for the "most" here? Certainly there were prominent contemporaries of Galileo who took the star size objection seriously.
>And again, the opposition from the Church was due to theological and political reasons.
Partly. The Church didn't want to make theological revisions in the absence of a compelling scientific case for heliocentrism. So the scientific status of the claims was important as well.
Most of the major scientific minds beyond the control of the Inquisition (i.e., in Protestant Europe). Heliocentrism was widely accepted by the time of Galileo's death, even though diffraction had not yet been understood (meaning that the star-size objection was still unanswered). It's significant that the next generation of scientists - Hooke, Newton et al. - were committed to the New Science, rather than the old geocentric worldview.
> So the scientific status of the claims was important as well.
The scientific status of the claims was irrelevant to the Church. The idea that it was is pure modern apologia. From the context of the times (the Counter-Reformation) and the texts of the Inquisition's decisions (which emphasize the heretical nature of heliocentrism), it's clear that what the Church cared about was enforcing its control over doctrine. This was an era in which the Church was in a bitter battle against heresy, trying to fight the spread of Protestantism and reassert control.
Of course the Church wanted to enforce its control over doctrine. But the Church was also fully aware that the Bible could potentially be interpreted in a way that was not contrary to heliocentrism. It simply wanted to avoid making a fairly significant doctrinal revision in the absence of a compelling scientific case for heliocentrism. That is not to say that such restrictions on scientific work are justified, merely that it's inaccurate to see the Church in this instance as acting from blind dogmatism.
The Inquisition's assessment of heliocentrism explicitly contradicts your claim:
> All said that this proposition is foolish and absurd in philosophy, and formally heretical since it explicitly contradicts many places the sense of Holy Scripture, according to the literal meaning of the words and according to the common interpretation and understanding of the Holy Fathers and the doctors of theology. - The Inquisition, 1616
Your claim that
> It simply wanted to avoid making a fairly significant doctrinal revision in the absence of a compelling scientific case for heliocentrism.
... is simply not supported at all by the Inquisition's own statements. The Inquisition was very clear that heliocentrism must be false, because it contradicted the literal meaning of Holy Scripture. The Inquisition didn't say that heliocentrism was an open question to consider. It positively declared that heliocentrism is false and that the Earth stands still, and it grounded that statement by pointing to a literal reading of Scripture.
> it's inaccurate to see the Church in this instance as acting from blind dogmatism
I don't see any possible way to interpret the Inquisition's judgment on heliocentrism as anything other than blind dogmatism. In modern apologia, the Inquisition's rulings are rarely cited, because they contradict the key points that modern apologists make (about the Church supposedly being interested in scientific caution, etc.). I get the sense that people are trying to defend the 17th Century Church from criticisms rooted in a modern sensibility (which accepts empiricism and rejects religious dogma), ignoring the fact that the 17th Century Church (and most people in Western Christendom at the time) did not share our modern sensibilities.