Comment by Jun8 | Hacker News Reader

Comment by Jun8 | Hacker News Reader

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The premise of this article is wrong: heliocentric was not rejected because ancient scientists were foolish or they were afraid to speak up to established theory. It was not accepted because egocentrism produced better results!

They correctly understood that heliocentrism predicted a parallax but failed to measure that with the primitive observational equipment they had. I thought this was a commonly known fact, together with the myth that the ancient believed Earth was flat, but evidently not.

For further reading: https://physics.stackexchange.com/questions/26291/why-did-th...

> They correctly understood that heliocentrism predicted a parallax but failed to measure that with the primitive observational equipment they had.

Aristotle in De Caelo (Book II, part 14):

> The earth, then, also, whether it move about the centre or as stationary at it, must necessarily move with two motions. But if this were so, there would have to be passings and turnings of the fixed stars. Yet no such thing is observed. The same stars always rise and set in the same parts of the earth.

* http://classics.mit.edu/Aristotle/heavens.2.ii.html

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

See also:

> In the mathēmatikoi tradition of Pythagoreanism the Earth was removed from the center of the universe. The mathēmatikoi believed that the Earth, along with other celestial bodies, orbited around a central fire. This, they believed, constituted a celestial harmony.[24]

* https://en.wikipedia.org/wiki/Pythagoreanism#The_mathēmatiko...

> heliocentrism predicted a parallax

Also, they didn’t have a theory of gravity so the lack of a sensation of moving with the earth and the fact that objects fall straight down were not expected unless the earth was stationary. There were also other more philosophical arguments for geocentrism that were compelling given the cosmology and science of the time.

> I thought this was a commonly known fact… evidently not.

Especially given how this is tied up with the common use of the Galileo affair as an example of faith vs science despite faith being common between Galileo and the Church Authorities to which he ran afoul.

Galileo and the Church had the same fundamental belief: the Universe was designed by an all-powerful God and that God picked laws of physics that were mathematically elegant and beautiful.

The Church was not nearly as closed-minded about heliocentric theories in Galileo's time as is commonly thought. Their position was that if empirical evidence clearly showed that the universe did not work the way the Church thought that the Bible said it worked then the Church must have misinterpreted the Bible.

The problem with Galileo's heliocentric theory was that it was empirically not correct. If some observation didn't fit in with his theory and changing the theory to accommodate it would make the theory ugly or inelegant Galileo would dismiss that observation as observational error. God, he believed, would not make an inelegant universe.

What got him in trouble with the Church wasn't that he proposed a heliocentric theory. It was a combination of 5 things.

1. His theory wasn't better than the best current geocentric theories at actually predicting things.

2. He had a very big ego.

3. He was an asshole. If he saw you are a rival or as an inferior he was intolerant and rude to you. Because of his big ego, "inferior" included pretty much everybody.

4. He was a celebrity. The rich and powerful would regularly invite him to attend their gatherings.

5. He had a terrible sense of politics. #4 regular brought him in contact with people who could make his life miserable if he annoyed them too much, and #2 and #3 ensured the he did so.

There have been a concerted effort to reframe the story because it remains so embarassing to the church. Yeah it is true Gallileo was arrogant and failed at playing the politicial game. He might have avoided the conflict if he had been better at sucking up to the pope.

However, the church forbade heliocentric theories up until the middle of the eighteenth century, long after Kepler and Newton. So clearly it wasn’t a question of evidence.

Oh, wow. This is pretty different from what I learned in school. Where can I read more about this?

The article linked in this comment [1] is good.

[1] https://news.ycombinator.com/item?id=39582243

+1 Myth of the flat Earth

For some years I gave talks about this (Germany), it is astonishing how many people think that the idea of a spherical earth is a new one.

"The myth of the flat Earth, or the flat-Earth error, is a modern historical misconception that European scholars and educated people during the Middle Ages believed the Earth to be flat."

https://en.wikipedia.org/wiki/Myth_of_the_flat_Earth

Many such ideas are the work of Enlightenment pamphleteers engaged in self-flattery and anti-Church propaganda (including the Protestant variety). By straw manning the Middle Ages (especially the Middle Ages, as many of these types had an ax to grind against the Church) or the ancients as superstitious imbeciles, it makes them look better, these true men of reason, in the eyes of the ignorant whom they sought to impress.

And wacky ideas like fundmentalism are likewise very new historically, but eagerly seized upon by our modern sophists who, again, have an ax to grind.

> self-flattery

Lol.

> By straw manning the Middle Ages (especially the Middle Ages, as many of these types had an ax to grind against the Church) or the ancients as superstitious imbeciles, it makes them look better, these true men of reason, in the eyes of the ignorant whom they sought to impress.

This is a great point - and still relevant. Academia does this to this day, attacking researchers like Jared Diamond, pooh-poohing the work of (very) ancient mathematicians and astronomers, or diminishing the insanely impressive craftsmanship shown in, eg, 30-50 thousand year old flutes, carved with perfect pentatonic scales.

Pentatonic scales! Well over 30,000 years ago! The implications of that are astounding.

I remember being taught in second grade that everyone believed the world was flat and only Columbus believed it was round. Turns out that not only everyone believed the world was round, but Columbus was wrong about the size of the earth and that was what led him to think traveling West would be a shorter route to Asia. Those who dismissed him were right about the size of the earth. Neither had any idea about the large landmass between Europe and Asia.

Furthermore Copernicus’s system had lower accuracy and more epicycles. There wasn’t any real reason to prefer heliocentric models until Kepler.

Kepler makes Copernicus look like a tool.

A neat example of how the predictive power of a theory does not guarantee its correctness. Even if the theory and its predictions were incremental refined and improved over time.

What measure is there for assessing the correctness of a theory aside from predictive power?

Here we have a theory which turned out to be fundamentally wrong while having predictive power.

Maybe every physical theory is just a model approximating something that can at any time be replaced by by a better model that is still just that, a model.

> Here we have a theory which turned out to be fundamentally wrong

What makes you think so? How is Ptolemaic theory "fundamentally wrong" where our best current physical theories are not?

> Maybe every physical theory is just a model approximating something that can at any time be replaced by by a better model that is still just that, a model.

This is indeed our current view of physical theories. But you realize, don't you, that once you accept this, it invalidates your criticism of Ptolemaic theory? Ptolemaic theory was a model. For centuries it was the best model known in terms of the accuracy of its predictions, which were accurate enough to predict things like eclipses years in advance. We now have better models, but none of that invalidates Ptolemaic theory's achievements. It just means we have now found better approximations.

In fact, our modern viewpoint, specifically relativity, even helps us to understand why the Ptolematic model worked as well as it did: it is one way of describing what you get if you use an inertial frame centered on the Earth to analyze the motions of the Sun, Moon, and planets! IIRC Steven Weinberg, years ago, wrote a paper that expounded this in some detail.

I find it hard to quantify wrong in this context.

Maybe wrong / right are endpoints of a sliding scale of accuracy, and maybe certain quantities on that scale become qualitative in my perception .

Was it fundamentally wrong?

Or did we just find another model that:

1. Accurately predicts phenomena the old model predicted accurately and predicts things we hadn't expected from the previous model or from our data that we later measure to be correct.

2. Effectively describes phenomena previously thought to be unrelated to the problem of interest.

3. We appreciated the simplicity of. (i.e. We could come up with more ad-hoc silliness that makes the old model accommodate our new data, but why?)

What's interesting about Ptolemy is that in a sense there is nothing inaccurate about his model. In my reading, it could hardly be called a model so much as a technique for creating models. Extending it to account for any deviations from our empirical measurements is trivial: just add another epicycle. The modelling technique Ptolemy demonstrates in his Almagest, seems to me to just be the Fourier transformation of a periodic function.

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