Hacker Newsnew | past | comments | ask | show | jobs | submitlogin
The Great Ptolemaic Smackdown: From Plausible to Proven (2013) (tofspot.blogspot.com)
86 points by telotortium on May 15, 2023 | hide | past | favorite | 56 comments


Basically the church wasn’t as crazy or evil as they’re portrayed now with their persecution of Galileo: he didn’t actually have convincing evidence because the real theory took hundreds of years later to be accepted. It’s important and satisfying to see our ancestors weren’t simply superstitious mystical fools, just people who were behaving somewhat reasonably with the information they had at the time. The incentives around them played a role but didn’t consume every facet of their decision making. Great article.


The amount of "made major discovery, never published or told anyone, found in his files after death" that keeps happening also shows an entirely different outlook on science that we don't really have anymore, I feel. Sure, some may have been trying to build some grand unified theory and keeping everything close to their chest (and then died), but I suspect a majority were just doing this stuff because it was damn amazing and they really didn't feel the need to tell anyone about it in particular.


"Science" didn't really exist for another couple centuries. This was just wealthy dudes having a fun hobby. The same way people of means today have "charitable organizations" to play around with, wealthy people back then liked to dabble in "natural philosophy"


A lot of those discoveries couldn’t be proven for many years after the deaths of their authors. So it was hard to tell how significant they were.

A lot of the things that Galileo said couldn’t be proven either. In fact some were outright wrong and some could be directly disproven based what was know at the time (e.g. reconciling the size and distance of stars).

So either they couldn’t tell anyone because nobody would believe them, they weren’t sure about how significant it was or maybe it was just irrelevant at the time (e.g. the Ancient Greek steam engine)


Many probably didn’t want to risk being publicly shown they were wrong I suppose.


> Basically the church wasn’t as crazy or evil as they’re portrayed now with their persecution of Galileo: he didn’t actually have convincing evidence because the real theory took hundreds of years later to be accepted.

Sorry, what? They put him under house arrest for having an astronomy theory they disagreed with. That's absolutely crazy. "Evil" isn't a word I generally use, but if I had to apply it to something, it could reasonably be applied to this as well.

Whether or not there was adequate evidence for his theories at the time is irrelevant: you don't imprison someone for an astronomy theory.


While I certainly don’t agree with them (the church), it’s not quite as evil as I had previously thought.

First, he was kept in a palace, and he was permitted to continue publishing until his death. Second, according to the article he had made a lot of enemies in ways that other scientists of the day, who also held heliocentric beliefs, hadn’t done. Lastly, he was pushing science that there wasn’t evidence for and that required new assumptions to make up for the current assumptions they were trying to prove. Like I said, I don’t agree with them but I also have the luxury of hindsight.

One way to look at it from the church’s pov may have been that he was making up a bunch of stuff that wasn't supported by evidence and also contradicted directly their institution, so they might have perceived him as just creating political trouble and instability. People in the past would make up all sorts of lies back then that would later be used as justification for war, especially when these things had some sort theological underpinnings to properly motivate one side against another.

It’s definitely not good but I now see, as how the history was laid out, that Galileo hadn’t really discovered anything himself, wasn’t even correct, didn’t have evidence for things he was putting fourth, and other scientists didn’t even agree with him. It was in fact Kepler who was much closer to a correct model, but he wasn’t a polemical of a writer so he didn’t have as much influence and legend as Galileo.


> It was in fact Kepler who was much closer to a correct model, but he wasn’t a polemical of a writer so he didn’t have as much influence and legend as Galileo.

By the end of the 1600s most people were using Kepler, not necessarily because they thought it actually matched reality (there was no way to verify one way or the other), but rather because the math was easier: no more epicycles!

Copernicus/Galileo still needed them:

> The Copernican model replaced Ptolemy's equant circles with more epicycles. 1,500 years of Ptolemy's model help create a more accurate estimate of the planets motions for Copernicus.[24] This is the main reason that Copernicus' system had even more epicycles than Ptolemy's. The more epicycles proved to have more accurate measurements of how the planets were truly positioned, "although not enough to get excited about".[25]

* https://en.wikipedia.org/wiki/Copernican_heliocentrism#Coper...


> They put him under house arrest for having an astronomy theory they disagreed with.

No, they put him under house arrest because he wrote a book about for the Pope is a moron for not agreeing with him, after the Pope explicitly asked him to write a factual account of the theories at the time.

Tyrannical? Sure, like any monarchy. But not anti-science.


One of the biggest issues in our history, was to call the middle ages "Dark ages" and what came next "Renaissance". Thomas Aquinas, Boethius were such great writers, for instance, among many others[1], they contested their faith and believes all the time.

[1] https://plato.stanford.edu/entries/medieval-philosophy/


Only the early middle ages were actually the "dark ages" (roughly 500AD to 1000AD, I think). They are called that only because of the relative lack of written material we have from that time.


Is that your interpretation, or you read it somewhere? I'm not saying that you are wrong, just that you find others interpretations - those that I was mentioning and that concerns me - everywhere.

stuff like, "The Middle Ages are often said to be dark because of a supposed lack of scientific and cultural advancement. During this time, feudalism was the dominant political system" is pretty common, even Wikipedia: https://en.wikipedia.org/wiki/Dark_Ages_(historiography)


If you look at the Wikipedia entry you cite, the very first clause of the first sentence is:

"The Dark Ages is a term for the Early Middle Ages"

That is the normal understanding of "dark ages" among historians.


Did you read the whole sentence?

"The Dark Ages is a term for the Early Middle Ages, or occasionally the entire Middle Ages, in Western Europe after the fall of the Western Roman Empire that characterises it as marked by economic, intellectual and cultural decline."

So the term is highly disputed and what I understood from there, is that no historian TODAY use Dark ages to describe any moment of the Middle Ages. At least not the serious historians.

I'm not Historian, I'm computer scientist and Philosopher. Dark Ages for me is first connected with the Greek Dark Ages, or Digital Dark Ages.


The scientific advancement claim is weird. It was also very slow during ancient Greek/Roman times and technological progress remained a somewhat foreign concept.

Arguably European/Byzantine society was already quite a bit more advanced in many areas by the 1100s. And the dark ages ended with the Carolingian renaissance. If an ancient work copied by the 900s AD or so the chances that it survived until our day is relatively high, if not.. well it’s gone.


> Tyrannical? Sure, like any monarchy. But not anti-science.

Tyranny is inherently anti-scientific. Right and wrong are determined by the validity of your observations and reasoning, not by power.


Absolutely not. They went after him because he insulted and ridiculed the chief authority. This is something that can still land you in court in today's France (and would have lead to much much harsher penalties in contemporaneous France). Insulting the king is also apparently, not allowed in today's UK for instance -- to say nothing of countries like Russia, etc.

So we're not so different than the catholic church of the 17th century.


> Insulting the king is also apparently, not allowed in today's UK for instance

what?


It's called Lèse-majesté (in English, that is). It is still actively persecuted in Spain [0], forcing Belgium to reinterpret its current laws in order not to extradite a rap singer.

[0]: https://en.wikipedia.org/wiki/L%C3%A8se-majest%C3%A9#Spain


I'm neither a legal expert nor a British citizen, so I may be wrong; but pacific protesters holding anti-monarchy banners were arrested by the Metropolitan police before the coronation of the new king, although they were neither violent nor doing any kind of obstruction.

Holding a sign in the street can land you in jail in the UK, in 2023.

https://www.theguardian.com/uk-news/2023/may/09/tory-mps-con...

https://www.bigissue.com/news/activism/public-order-bill-exp...


Insulting the king is not illegal in the UK. The protesters were arrested under various public-order pretexts.


Exactly, pretexts – more or less explicitly admitted by the authorities in connection with the arrests. What's actually illegal in the UK is pretty obviously protesting against the king or the monarchy in general.


>Sorry, what? They put him under house arrest for having an astronomy theory they disagreed with. That's absolutely crazy.

That's the unfortunately prevalent "TikTok"-level version of the history.

Has little to do with the actual reason, tons of people, including scientific-inclined people of the church had public alternative astronomy theories of their own or discussed existing ones.


> That's the unfortunately prevalent "TikTok"-level version of the history.

It is also almost verbatim what I was taught in an Ohio school in the 90s.


> It is also almost verbatim what I was taught in an Ohio school in the 90s.

"History changes every day." — Frank Herbert

I bet you were also taught in science class that Pluto was a planet. :)


Look I see where you're coming from of course, living in the same culture you do.

But it's always important to remember that people believe their religions. And not just the clergy. The past is a foreign country, they do things differently there.

They didn't imprison him for astronomy theory. Astronomy was largely not separable from theology. Both Galileo and his judges believed this.


> But it's always important to remember that people believe their religions. And not just the clergy. The past is a foreign country, they do things differently there.

Sure, and I wish more people understood that. But that doesn't make it any less crazy or harmful.

And, the next step in understanding this is to recognize that we're not different. It's still crazy and harmful when we do things like this.

> They didn't imprison him for astronomy theory. Astronomy was largely not separable from theology. Both Galileo and his judges believed this.

Sure... and they were wrong.


> Sure... and they were wrong.

They weren’t. Theology was the primary (pseudo)scientific approach used to explain the law of nature at the time.


The primary (pseudo)scientific approach used to explain the law of nature at the time was wrong. And remains wrong, which is why I'm willing to die on this hill--this ideology is still harming us today.


I disagree it laid the foundations for modern scientific thought.

It couldn’t have developed the way it did without theology and the Catholic church..


> you don't imprison someone for an astronomy theory

Every time I spend some time on dating websites it occurs to me that it might be a good idea to imprison people for astrology theories. Given the adequacy of evidence they had at the time, astronomy, astrology, it's just about the same thing, so I can sympathize


The church defended a scientific assertion based on theology and used their (absolute) political power to curb other worldviews.

Even assuming that Galileo could not prove beyond reasonable doubt heliocentrism as a physical model, and that the Church accepted that the Ptolemaic model wasn't valid - the Church took an active part in asserting that "heliocentrism is heresy". They could have said it's not their own matter to pontificate about and they instead went after Galileo asserting that he overstepped his boundaries.

It's very possible that Galileo (and the stories about him in later epochs) was not 100% in his assertions and his arguments. And it's important to look at the history from an objective point of view. However if you look at it as a battle for freedom to do experiment-based research, yes, the church was evil at that time.


> the Church accepted that the Ptolemaic model wasn't valid - the Church took an active part in asserting that "heliocentrism is heresy".

It was not that straightforward. The Tychonic model was already accepted and generally the church was quite tolerant (by premodern standards) towards scientific debate and the heresy decision was mainly an outcome of political/personal squables.

The next pope, Urban VIII had no issues with allowing measured debate of heliocentrism. What landed Galileo in house arrest was him writing a book which directly mocked the people (at least everyone thought that it did).

> However if you look at it as a battle for freedom to do experiment-based research, yes, the church was evil at that time.

Which disregards the fact that it didn’t have much issue with other scientists doing that. In fact generally the Catholic church and its affiliated institutions were almost the only places where any scientific research was done at all for quite a while..


Sure, but we are still talking about an uppity sect of superstitious people (with great learning in their superstition but not much else). They had no business locking people up at all, no matter how much the Pope didn't like being called Simplicio.


Galileo didn't have evidence of his theory? Surely he had a little and didn't just pull it out of thin air. How much evidence was there for the Ptolemaic system?


They burned Giordano Bruno at the stake for hypothesizing that the sun was a star. Anyone willing to do that over an astronomy disagreement is evil.


That's not why they burned him at the stake. If anything it was because of his hermeticism.


There's a whole bunch of stuff that would have ruffled feathers:

> While Bruno began as a Dominican friar, during his time in Geneva he embraced Calvinism.[5] Bruno was later tried for heresy by the Roman Inquisition on charges of denial of several core Catholic doctrines, including eternal damnation, the Trinity, the divinity of Christ, the virginity of Mary, and transubstantiation.

* https://en.wikipedia.org/wiki/Giordano_Bruno


> John Lukacs used to tell us is that we "must consider the battle of Salamis as if the Persians might still win." Meaning that you want to understand what happens in 1633, you can't consider things learned in 1687 or 1803. The mid-17th century had no clear concept of inertia, of gravitation, of forces, etc.;

So basically we should avoid to do any kind of anachronism, which people do as well, while interpreting historical events or even worse historical figures.


As far as I can tell, this is an excellent summary of the issues, but this caught my attention (my emphasis):

If the earth were whipping around the sun, we should see parallax among the fixed stars, but do not. The Copernicans answered, "Well, yeah, but maybe the stars aren't just far away but really really far away." But you cannot save an unproven hypothesis by asserting a second unproven hypothesis. The stars had to be relatively close because otherwise their observed diameters would mean they were ginormous entities. Some Copernicans embraced this and said "Goddidit!" Who cared how enormous the stars were, since God was infinite.

You can 'save' a hypothesis as a hypothesis by showing that the objection is incomplete, and this is what happened here: the stars are indeed so far away that parallax was not then observable. The apparent corollary, that the stars must therefore be enormous, turned out to be false for a reason not suspected by either side: the apparent angular size of stars as observed by telescope is due to diffraction (the Airy disc.)

The author picks up this thread in the comments, saying

...it was not evident at the time which model was more true nor even why one model ought to be more true. That was the contribution of Newton's theory of universal gravitation...

Stellar parallax was not observed, however, until 1832, and the Airy disc was not explained until 1834, while Newton's gravitational explanation became widely known in 1686. Furthermore, neither Newton nor any of his contemporaries explained gravitation (Newton himself saying that he "brooked no hypothesis" in that regard), or presented any evidence independent of astronomical observations (i.e. the phenomena to be explained) for either its universality or that it follows an inverse-square law.

It turned out, therefore, that what was arguably the strongest objection to heliocentricity was put aside, not because it had been explained away, but because it paled into relative insignificance in comparison to the explanatory power of Newton's theory.

In this view, Galileo, for all his faults, was not just a self-aggrandizing promoter who happened to latch on to what turned out to be a correct theory; he was a respectable scientist of his day who had what turned out to have good (mostly) intuitions about which ideas were on the right track. For a more general moral, it is probably this just this: read Kuhn - and probably also Popper, who, at least according to David Deutsch, presents explanation as the ultimate goal of science.


The author looks knowledgeable, and the text is certainly interesting to read, but I really dislike the slang here and there.. You know, people of whom you talk, were more refined than the bums on today's tv screen.. I suppose it is the author's "sense of humour". Or the absence of mine, but still..


Probably the latter. Some audiences can be very prudish.


The able of contents for the entire weblog post series is at:

* https://tofspot.blogspot.com/2013/10/the-great-ptolemaic-sma...


> Christie, Galileo’s great bluff 2010

A search for this returns only this article. Anyone knows what it is? Is it a book, an article, a scholarly publication...?


If you scroll down to the bottom of the post, there is a references section with a link to it.


It seems to be a blog post titled "Galileo’s great bluff and part of the reason why Kuhn is wrong." by Thony Christie dated Nov. 12, 2010, at https://thonyc.wordpress.com/2010/11/12/galileo%E2%80%99s-gr... Google led me there.



I think this is the same writer as interviewed on the amazing "subject to change" podcast - cannot find the link ATM


This person seemed like someone with a lot of axes to grind, and on investigation they co-wrote one of the worst science fiction books I've ever read ('Fallen Angels').


thanks for sharing


Am I the only one who finds this post impossible to read? Like it seems to be in dire need of a thesis statement, transition verbs, meaningful section titles, etc.


The link the OP submitted is the last of a 9-part series of posts.

Here's a table of contents for the site author's posts on this topic: http://tofspot.blogspot.com/search?q=Great+Ptolemaic+Smackdo...



Probably not the only one, but I enjoyed the post tremendously (it's morning in my time zone, first read of the day accompanied by an espresso). I understand why one might find that style annoying, though.


It was a bit difficult to read, but pretty great overall


I find it pleasant, snappy.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: