Galileo’s revolutionary contribution

A good primary source

In An interesting question Thony C at The Renaissance Mathematicus responded to a comment at my post, Early history of science, with his own blog article. While it  mainly discusses the nature of censorship I would like to respond to some comments he made about the Galileo affair.

I will leave aside his/her tactic of blaming the victim – which seems quite fashionable among religious apologists writing on this issue today. For example Thony C claims:

“Nobody had been really bothered by the potential conflict until Galileo and Foscarini had made it into a real conflict by suggesting a theological solution thus creating a real problem for the Church;” “In his unconsidered and over hasty actions Galileo had forced the Church to ban the heliocentric theory.”

There is something unpleasant about excusing all the actions of a huge institution like the Catholic Church and its Inquisition and putting all the blame on an individual. Moreover an individual who is threatened with torture and sentenced to imprisonment! Soviet apologists no doubt blamed Andrei Sakharov for his confinement to the city of Gorky and Aleksandr Solzhenitsyn for his expulsion from the country. That’s the trouble with apologists – their loyalties.

However, I would like to deal here with the so-called “theological solution” which Thony C presents as the real problem. Unfortunately this “crime” is usually not discussed in detail, yet apologists often wish to use it to divert attention away from the scientific issues. Was the theological problem simply non-acceptance of a geocentric model which was supposedly made factual by its presentation in the Christian bible? Was it just a matter of semantics, the hubris of including scientific questions within the domain of theology?

Thony C gives a clearer idea in his comment:

“The crime the these two men committed in the Church’s eyes was not that they propagated heliocentrism, which they did, but that they told the Church how to interpret the Bible and that was definitely a no, no.”

So was it a matter of interpretation, or more correctly who should do the interpreting and how?

Galileo’s sentence

Firstly, let’s be clear how the Inquisition saw Galileo’s “crimes” by looking at this extract from his sentence (my emphasis – in this post I am quoting from The Essential Galileo – a very useful source of primary documents):

“We say, pronounce, sentence, and declare that you, the abovementioned 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. Consequently you have incurred all the censures and penalties imposed and promulgated by the sacred canons and all particular and general laws against such delinquents. We are willing to absolve you from them provided that first, with a sincere heart and unfeigned faith, in front of us you abjure, curse, and detest the above-mentioned errors and heresies, and every other error and heresy contrary to the Catholic and Apostolic Church, in the manner and form we will prescribe to you. Furthermore, so that this serious and pernicious error and transgression of yours does not remain completely unpunished, and so that you will be more cautious in the future and an example for others to abstain from similar crimes, we order that the book Dialogue by Galileo Galilei be prohibited by public edict. We condemn you to formal imprisonment in this Holy Office at our pleasure. As a salutary penance we impose on you to recite the seven penitential Psalms once a week for the next three years. And we reserve the authority to moderate, change, or condone wholly or in part the above-mentioned penalties and penances. This we say, pronounce, sentence, declare, order, and reserve by this or any other better manner or form that we reasonably can or shall think of.“

So clearly the specific point of issue was that of heliocentricism. But included in this is that the church had proclaimed geocentricism a “fact” because it (in their opinion) is revealed by “Holy Scripture.” So the issue becomes one of epistemology rather than a scientific theory. Do you derive your understanding of nature from “Holy Scripture” or from the evidence of nature? No doubt seen by the Inquisition as a “theological” issue but really an important philosophical one.

Epistemology the real issue?

It’s important to see the key role of different epistemologies here because apologists will often make an issue of the difference between hypothesis and truth, or should I say “Truth.” That Galileo and Kepler, for example, had not been able to get supporting evidence from parallax measurements (they didn’t have the technology/accuracy). But again that is a diversion – apologists concentrate on the degree of empirical confirmation for heliocentricism (and ignore the lack of empirical confirmation for geocentrism), while purposely ignoring what the Inquisition and Church understood as the “Truth.”

And Truth, of course, was that laid down by “Holy Scripture” – really interpretation of that Scripture by the Church authorities. Or a select few of those “authorities,” in this case, as the interpretation was so dubious and varied. The “Holy Scriptures” did not even name the planets, let alone give a model for their arrangement.

And the Inquisition’s claim that the geocentric model was a fact had not required the sort of real evidence they were demanding for the Copernican model.

So, on the one hand the church or theological “authorities” claimed the sole right to interpret “Holy Scripture”, and thus determine “Truth.” They determined by this shonky revelation that the geocentric model was “true”- the fact. Anyone else who attempted their own “interpretation”, or suggested a different epistemology like relying on evidence, was committing a crime.

Perhaps the theologians could be pragmatic. Some documents imply their “interpretation” would change once the empirical evidence was overwhelming. (A strange admission that revelation is a lousy epistemological method). A Catch-22 bureaucratic situation given that Galileo, and other natural philosophers, had been urged in 1616 to:

“abandon completely the above-mentioned opinion that the sun is the center of the world and the earth moves, nor henceforth hold, teach, or defend it in any way whatever, orally or in writing; otherwise the Holy Office would start proceedings against him.”

As for these “proceedings” – well, 16 years before Bruno had been burned at the stake for heresy!

Thony C suggests that Galileo and others told the Church how to interpret the Bible.” Its worth actually understanding what Galileo said about interpretation.

He did actually offer, as an aside, a different interpretation to the then accepted one of the Joshua story where the sun stood still to enable a battle to be won.  He suggested that the story could not be “explained” by the Ptolemaic geocentric model, but could be by the Copernican heliocentric one. Or more correctly that the Copernican model enabled a more literal interpretation of the scripture.

However, his general comments on scriptural interpretation are of more value.

Scriptural interpretation

Galileo was a devout Catholic so did in fact accept scripture as “Holy” and “correct.” But:

“Scripture cannot err, nevertheless some of its interpreters and expositors can sometimes err in various ways. One of these would be very serious and very frequent, namely, to want to limit oneself always to the literal meaning of the words”

Moreover interpretation was required because by necessity the “holy ghost” had to adapt its dictated language to the culture and prejudices of the time:

“in order to adapt it­self to the understanding of all people, it was appropriate for Scripture to say many things which are different from absolute truth in appearance and in regard to the meaning of the words.”

In contrast, no “interpretation” is required for natural situations:

“nature is inexorable and immutable, and she does not care at all whether or not her recondite reasons and modes of operations are revealed to human understanding, and so she never transgresses the terms of the laws imposed on her”

As a devout Catholic he saw it this way:

“Holy Scripture and nature both equally derive from the divine Word, the former as the dictation of the Holy Spirit, the latter as the most obedient executrix of God’s commands.”

But while “interpretation” of “Holy scripture” was required, even demanded, our perception of, and ideas about, the real world must be derived from evidence.

“therefore, whatever sensory experience places before our eyes or necessary demonstrations prove to us concerning natural effects should not in any way be called into question on account of scriptural passages whose words appear to have a different meaning, since not every statement of Scripture is bound to obligations as severely as each effect of nature.”

A necessary requirement for the scientific revolution

I doubt that Galileo was the only Catholic who saw this. And imagine it was part of the theological debates of the time. However, I think it also should really be seen as part of the general philosophical debates. What Galileo was suggesting was a very necessary step in scienctific evolution.

For science to progress, for it even to return to its earlier power, the struggle between two different epistemologies had to be resolved. In effect the breaking away of science from the old theology and philosophy of revelation was a necessary requirement for the scientific revolution.

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17 responses to “Galileo’s revolutionary contribution

  1. Question: are you referring to Thony (@rmathematicus) as a “religious apologist”? Because you repeat the lines about the religious apologists quite often, and very much connected when you bring up his comments. Just trying to understand total point of view here, and all points explicit or implict.


  2. No Gurder, I am not referring to Thony C with that description. I don’t know him’her from Adam/Eve.

    However, some of his arguments are similar to arguments currently fashionable amongst Christian apologists. Their motivations are rather obvious – I don ‘t know Thony C’s.


  3. Ken – @Gurdur’s question was the one that first occurred to me. We should be clear here that Thony’s account is by and large the one that is now taught to undergraduates and masters’ students in history of science. It is the version I learned from my reading and my supervisors: people with PhDs in history of science, teaching in a renown university, with first-class research records, whose background was in science (if that makes a difference), who were themselves atheists and agnostics.

    Good historians have worked on this topic in recent years and produced a much more interesting, sophisticated and well-documented account than deserves the name apologetics. It may not be the account you prefer, but it’s the one produced by those who have dedicated their lives to researching it. Historians are not interested in attributing ‘blame’ and should not be out to find evidence to support a preconceived thesis. We all have our biases, but history has developed methodologies, a wealth of data and professional norms that mean that biased work and apologetics will be criticised.

    Also worth mentioning is that is now generally agreed that Bruno’s heresy was largely theological (pantheism, magic, Arianism and more) and not his heliocentrism.


  4. Rebekah, I made it very clear I am not describing Thony C as a religious apologist – just that he has used similar arguments. Nor did I comment on Bruno’s heresy – just that he was an example of how heretics may have expected to be treated.

    Otherwise, I can’t see from your comments what your problem is. I have simply referred to the primary sources to identify the reasons for Galileo’s treatment and for his understanding of theological interpretation.

    My conclusion about the revolutionary significance of his comments are mine but I think they are reasonable given that these philosophical changes were a necessary condition for the scientific revolution.

    Why not engage with the details if my article instead of vaguely lecturing me about your understanding if consensus?

    I think you have emotionally reacted to my article and made unwarranted assumptions.

    By the way, I have responded to some commenters on Thony C’s blog who have completely misrepresented the facts around the Galileo affair. Claimed theologians as scientists for example.


  5. Richard Christie

    It should be pointed out that Thony’s piece was in response to a question for comment on the placement of Kepler’s works on the Librorum Prohibitum.

    The more I mull the response over it boils down to “because of the association of Kepler’s work to Galileo’s, Galileo overstepped the line by questioning theological matters in a scientific argument”

    So let’s be clear on this, the Church banned one man’s scientific work because of the transgression in theological arena of another man. And not just one man’s work, the Church saw fit to attempt suppress an entire field of inquiry.


  6. Richard Christie

    Oh, and the argument goes on to say that the suppression was not because of the science.

    Yeah, well..


  7. Yes, Richard. But his next post goes on to attack the science argument! I find his understanding of science and it’s evution, and the history of the Galileo affair, very simplistic.


  8. “Claimed theologians as scientists for example.”

    Like Isaac Newton? Who comes after Galileo? Or like Benedetto Castelli, who defended Galileo? Both professional theologians at that, especially Isaac Newton. Or like Galileo himself, who did some amateur theology himself? But theologians all, if one is not too snooty to include Galileo as one despite his being an amateur.

    Kepler, well he was an astrologer, not a theologian. Brahe was an alchemist. Or in other words, your strict dichotomy between theologians and scientists is an imposition of a historically false anachronism.


  9. You’ve hit the nail on the head, Ken. The Galileo Affair is not about interpreting scripture but establishing authority for epistemology: Galileo argued that the universe and not scripture was the final arbiter and for this he was censured. (Remember, he also suffered through the death of a daughter in a nunnery during this time… coincidence, I’m sure.)

    The reason why Galileo is so important to the history of science is because he showed why Aristotelian physics was fundamentally and fatally wrong by assuming that things had natures (a rock, for example, was understood to be heavy because it had the property of being heavy… that was its nature). Galileo showed through empirical evidence that things only seemed to have natures but, in fact, responded to external, consistent, and predictable forces. This key understanding is what led Newton to say that if he saw ‘farther’ than others it was only because he stood on the shoulders of such giants as Galileo.

    The issue with the slow death of Aristotelian physics started by Galileo directly undermined the metaphysics of catholic theology that had been built upon this unstable foundation. Change the order of science below theology, change the theology itself… and this is something the church has never been able to do with grace and reason because it cannot and still claim its primacy in human affairs.

    Of course the church couldn’t stand by and allow this seismic shift in the order of primacy to go unchallenged, which is why it demanded a retraction from him of the theory that the evidence supported while keeping the hypothesis itself acceptable only as an hypothesis as long as evidence from the universe itself was held to be subservient to faith claims. We see this ongoing battle to this day not just from the church’s position on specific issues but fighting against any restraints on its theology from reality itself. And the catholic church is not alone: this is the same battle every religion that tries to be primary in human affairs must undergo.


  10. I find it strange that some people seem to think that “theological disagreement” somehow makes persecution, imprisionment or even burning to death somehow allright, or perhaps more understandable.

    The churches actions in these cases seem to me to be mainly about power, and the punishment of any perceived challenges to that power. In my book, that clearly supports the idea of a “a clash of epistemologies” as obviously any evidence based approach is going to clash with the powers of the day when it is held up as more informative or correct than the current scriptural pronouncements. I thought Ken covered this point quite nicely under the heading scriptural interpretation.


  11. Gurder – I can’t understand your hostility.

    My reference to “claiming theologians as scientists” was to a commenter on another who assured me that in 1616 the Inquisition had appointed a panel of scientists who came down on the side of the Pythagorean/Ptolemeic model of the universe. He suggested that actually Galileo was using “faith” to argue against science, or the scientiifc consensus.

    The documents actually show that this panel was not made up of astronomers. (Clearly if it had been genuine it would also have included an outstanding astronomer like Galileo.)

    No the panel was made up of eleven theologians! Perfectly understandable for the time. One would probably find unusual the idea that a group of scientists should be gathered for such deliberations. And the real issues were about theological interpretation not science.

    Now, I object to people using such fibs to bloster their arguments (I was amazed at the hostility shown towards Galileo’s science on that blog). But I have no problem with the fact that outstanding scientists of the time also had other beliefs that today we would consider mightily strange.

    That is the nature of reality.

    I often stress that even today I can point you to good scientists who nevertheless have other strtange ideas. Hell, I even knew one who was a member of the NZ ACT Party!


  12. tildeb – I think the point you make is important. Although this epistemological battle has basically been won amongst scientists, at least in their work, it is still unresolved in many areas of public life. And will probabl;y continue for some time yet.


  13. At the risk of retreading old ground: what is the contemporary 17th century definition or description of a “scientist”, which allows one to differentiate between a committee of “scientists” and a committee of “theologians”? (See Gurdur’s comment above.)


  14. Yemon, the word “scientists” was used by someone on another blog. In this context he was lying because the actual panel was made up of theologians and is described as such in the documents of the church at the time. The commenter was trying to suggest that their report was a conclusive scientific one – which it wasn’t. But it suited the aim of the inquisition who wished to prohibit any opinion supporting a Copernian model. It is rather pathetic for people today to use this panel decision to make claims about relative scientific acceptance of the different astronomical models.

    In those days terms like “natural philosopher”, “astronomer” or “mathematician” would have been relevant. Of course in translation from Latin or Italian into current English the words science and scientist get used. They crop up a lot in Galileo’s writings.

    But in conclusion the Church documents do describe the consultants panel as “theologians”. A credible scientific panel on this subject would probably have been described as “astronomers.” Maybe “mathematicians.” Certainly not “scientists” – although that may be used in translation.


  15. Thanks for the response, Ken. I just wanted to clarify what exactly you were inferring from the primary source. (Disclosure: I am, at least until I am swayed by further discussion or research on my part, more on the side of ThonyC and Rebekah Higgitt’s comments/claims. Any discussion should probably start with that in mind.)

    So: is one of your points that, had the report been more in line with Thony’s interpretation, the panel would have had “astronomers” or a suitable contemporary term, rather than “theologians”?

    Nitpicking on something in your post: you say So, on the one hand the church or theological “authorities” claimed the sole right to interpret “Holy Scripture”, and thus determine “Truth.” They determined by this shonky revelation that the geocentric model was “true”- the fact.

    Is your implication that they ignored the evidence at the time for a heliocentric model, because it would have undermined their claim to authority-via-exclusive-Scriptural-doctrine?
    (I’m not necessarily disputing this claim, although I’m not convinced it’s obvious; I just want to make sure I understand what you are saying.)


  16. Thanks for you precise questions Yemon. I will respond to the accurately because I think there are some important principles involved;

    1: First a general point. I find your disclosure that you are “more on the side of Thony C and Rebekah Higgitt’s comments/claims” strange That is, I am not used to the concept of “taking sides.” We have a lot of disagreements/arguments in science – fortunately most are dealt with by interrogating reality. By looking at facts and finding evidence. We are really on the same side and the evidence determines the final agreement or otherwise. That is what I am doing here.

    I don’t see myself as being on a different “side” to Thony C. I probably agree with much of what he/she says. However, we disagree about some things and I have referred him to factual material supporting my arguments on these. He made several misrepresentations of Richard Carrier for example. And withdrew at least one of them when I asked for evidence, and provided a quote to show his mistake. In this specific case of the Galileo Affair he has suggested I am wrong about the assessor theologians. I corrected him (and haven’t yet had a response) and anyway I had provided the document quotes previously in that thread (he even repeated one of them where the word “consultants” was used).

    He perhaps should hold back on his personal judgmentalism as he did imply my reasons for using the word Theologian was my hatred for the Catholic church! That is not professional.

    As for Rebekah – she has vaguely disagreed with me but refuses to get into specifics. Pity as they are important. However, she has said she may write a specific blog on Carrier – I look forward to that.

    2: “is one of your points that, had the report been more in line with Thony’s interpretation, the panel would have had “astronomers” or a suitable contemporary term, rather than “theologians”?” – Obviously that is a question for Thony C rather than me. I was being criticised for pointing out that Ye Old Statistician was incorrect to describe the assessors as “scientists”, that it is not a word that would have been used then anyway, and that actually they were theologians as the evidence clearly states. Thony disagree with me – his evidence is that I hate the church plus a quote from Finocchiaro which he/she interpreted incorrectly (and I had already provided). He/she presumably had not actually read my previous comment including the documentary evidence for my point.

    3: “Is your implication that they ignored the evidence at the time for a heliocentric model, because it would have undermined their claim to authority-via-exclusive-Scriptural-doctrine?” Well, actually I had not drawn any inferences at all. I was just correcting what I saw as either a very bad mistake or a purposeful fib.

    I think that before drawing inferences one should ensure the facts are correct. Neither Ye Old Statistician or Thony C seem to have actually done the work to establish that fact.

    In this post I was trying to show the fallacy of “Truth” determined by revelation. And that is certainly one of the points in the Church’s position.

    4: As for inferences. I actually am prepared to make some speculations based on this evidence. I don’t think the evidence was necessarily ignored (how can one determine that as the report from the assessor theologians is very brief) but the Church had made up its mind and they were concerned at growing dissatisfaction with that position. Hence the attacks on Galileo and the decision to request a report from the assessor theologians. And one is always suspicious of panels who produce reports from the huge institutions demanding them and using them to attack people they see as enemies and threaten with imprisonment.

    I am of course willing to accept any good evidence that would undermine my speculation. If you have any please let me know.

    Finally, I think I will put up an article here tomorrow including the text of the assessor theologians report. I have heard the claim made several times now that Galileo was using faith to argue against science. Ye Old Statistician even said “Then along comes Galileo telling them how to re-interpret the scriptures based on little more than his say-so and in the face of unanswered objections.” Anyone actually making such claims should not only look at Galileo’s scientific work. They should look at the actual standard of what is being used to support the Church’s position.

    Hopefully you will tell me what you think of the assessor theologian’s report when you comment on tomorrow’s article.


  17. Ken you seem incapable of a rational and dispassionate approach to this topic. I’ve seen this recycled Galileo narrative many times and you still seem incapable of placing the events in any historical context, and react emotionally to any one who points out your factual errors. I tire of your shallow posturing.


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