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Comment by marcofloriano

3 days ago

I completely agree with your comment. The common narrative about Galileo and the Church is often oversimplified and overlooks the intellectual context of the time. As you pointed out, it wasn’t about a crude Biblical literalism—after all, even centuries before Galileo, figures like Saint Thomas Aquinas, drawing on Aristotle, already accepted that the Earth is spherical.

By Galileo’s era, the Catholic Church was well aware of this scientific truth and actively engaged with astronomy and natural philosophy. The dispute was far more about competing models and the standards of evidence required, not a refusal to accept reason or observation.

Then I can’t help but think: if the author of the article didn’t even understand this, how can the rest of the article be correct if it started from a biased and almost false premise?

> Then I can’t help but think: if the author of the article didn’t even understand this, how can the rest of the article be correct if it started from a biased and almost false premise?

That seems pretty unfair. The article is clearly structured to treat the Galileo thing as an example, not a premise. It is supposed to be a familiar case to consider before going into unfamiliar ones. In that sense it clearly still works as an example even if it's false: does it not set you up to think about the general problem, even if it's a fictional anecdote? It's no different than using some observation about Lord of the Rings or Harry Potter as an example before setting into a point. The fact that it's fictional doesn't affect its illustrative merits.

  • > The fact that it's fictional doesn't affect its illustrative merits.

    Indeed, it may even reinforce the overall argument being made in the post we're discussing; the "Galileo vs. Catholicism" narrative is itself a linchpin trope in an empirical scientific worldview, with the trope reinforcing (among other beliefs) that "it's right and proper to pursue and advocate for objective truth even to the extent of making enemies of the most powerful."

    Considering the likely audience for a piece like this post we're discussing, that the Galileo narrative doesn't necessarily reflect what actually happened historically makes it a pretty good example on a meta-level. Are any of us who have the belief in the ultimate value of objectivity going to give up on it because a potentially weak example was used to support it?

Galileo started the troll himself depicting the opponent theory in the mouth of Simplicius.

And even with its acquaintances with the pope, he finished jailed at home. Far better than being burned alive like the Church did with Giordano Bruno.

So, yes, they are more nuances to the affair, but the case around lack of observable parallax or other indeed judicious reasoning is not going to create a great narrative to sell on the one hand, and on the other hand focusing on technical details is kind of missing the forest for the tree of what where the social issues at stake the trial examplified.

Was it during Galileo's era or was it a much earlier time with Greek philosophers when the idea of heliocentrism was rejected because the lack of parallax movement of the stars? The idea of stars being so far away they wouldn't show parallax movement wasn't acceptable without stronger evidence than what was available at the time, given how massive that would make outer space, so the simpler explanation was that the sun moved.

  • Earlier, for the most part. There was a fairly well known set of standard objections. A lot of the others were to do with the implications of the earth rotating, like the fact that things seem to fall straight down (not quite, but it was only after Galileo's death that someone managed to demonstrate this clearly, and not for lack of trying), and that you don't get a huge wind generated by the rotation (it does affect the winds, but you need a far more sophisticated framework for understanding motion that only really started to take shape with Newton to put this together). The star parallax thing was further complicated by an quirk of optics, which is that stars don't appear to be perfect point objects, they (to the naked eye and to telescopes) do have some apparent diameter, and that diameter implied that if they were far away enough to not have parallax, not only would the universe need to be much bigger, the stars themselves would need to be huge, many times the size of the solar system.

    It also didn't help that Galileo's model was still incorrect and inelegant, due to the insistence on circles and epicycles. It actually needed more cycles to explain than the geocentric version of the model! It was Kepler that actually got things right and elegant by allowing orbits to be ellipses.

    (As an aside, there's one exchange of letters between Galileo and a bigwig member of the church, where amusingly, to modern observers, the church guy was more correct about the astronomy and Galileo was more correct on the theology!)

    • This is a really good overview. However:

      > It actually needed more cycles to explain than the geocentric version of the model!

      This part is not true. The main advantage of Copernicus's model was that it reduced the number of epicycles needed. In the Ptolemaic system every planet (except the Moon and Sun) required an epicycle with a period of one year, which we now know was needed in order to account for the relative motion of the Earth on its own orbit. In a heliocentric system these epicycles could be eliminated. Copernicus presented his model more in terms of it requiring fewer calculations.

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> By Galileo’s era, the Catholic Church was well aware of this scientific truth and actively engaged with astronomy and natural philosophy.

I'm confused. Are you saying that the Church knew the Earth was round or not? If they knew, then it doesn't matter what arguments were made, it was all in bad faith and therefore wasn't scientific.

EDIT: Never mind, I misread

  • The sphericity of the Earth was not what Galileo and the Church were arguing about--they were arguing about whether the Sun revolved around the Earth, or the Earth around the Sun.

  • The idea that people used to think the Earth was flat is a common misconception. Sometimes medieval painters would draw the Earth that way for artistic purposes, but nobody seriously thought it worked that way for real.

    Why not? It's obvious to anyone who watched a ship sail over the horizon that the Earth must be a sphere because you see the body of the ship disappear before its sail mast does.

  • The church knew that the earth was round. Which is largely irrelevant, because Galileo argued for a heliocentric model vs the (at the time popular) geocentric model. Nobody argued that the earth was round

The author doesn't use the Galileo episode as a premise, only as a catchy illustration. If anything, the more nuanced version of the story seems to support their argument better than the simplified version does.

> Then I can’t help but think: if the author of the article didn’t even understand this, how can the rest of the article be correct if it started from a biased and almost false premise?

Same way Galileo could be correct about Earth circling the Sun despite basing it on incorrect assumptions :)