If you’re familiar at all with the history of science, you probably know the story of Galileo and the Catholic Church. The very short version is that Galileo advocated for the idea that the Earth revolved around the Sun. The Catholic Church considered that idea heretical, imprisoned Galileo, and forced him to recant his idea and “admit” that the Earth was stationary. At the end of his testimony, Galileo allegedly muttered, “E pur si muove” (and yet it [the Earth] moves).
When this story is told, it’s usually told in the vein of conservati vs. progressivism. There’s the old, stodgy, Catholic Church, defender of ancient busted ideas. There’s Galileo Galilei, iconoclastic scientist, pursuer of new truth. Eventually new ideas win out, but in the meanwhile, the old conservative institutions will make your life miserable (see every scientific culture war).
This interpretation isn’t totally off-base. But the actual facts of this case make it more complicated. First of all, one really basic question is this: why did the Catholic Church think that saying the Earth revolved around the Sun is heretical?
If you look in the Bible, the closest evidence you get to heliocentrism being heretical is in the book of Joshua during the battle of Gibeon. In this book, Joshua, the leader of the Israelites after Moses, leads the Israelites in a war against the Gibeonites. Joshua, to help the Israelites, stretches daylight hours into an entire extra day. He does this by commanding the sun and moon to stand still.
And…that’s it! That’s the strongest of the Biblical evidence. It’s not a lot. You have to go the extra step to realize that, in order to take Joshua’s command literally, it only works if you think the sun is moving in the first place, and that’s what causes the day to end. Of course, if you’re ok taking Joshua’s command metaphorically, in that he’s making the sun and moon appear to stand still by stopping the rotation of the Earth, you can pretty easily see this as supporting geocentrism.
This is a weird hill for the Catholic Church to die on (or to make Galileo die on). They ignored a lot of the rest of the Old Testament. For example, they had no problem ignoring the Biblical claim that pi was equal to 3, or the claim that the sky is actually a “firmament” (a literally solid dome) dividing “the waters above” vs. “the waters below”. Nobody got in trouble in 17th century Europe for using more accurate valuations of pi, or for accepting that comets and meteors pass through the Earth’s atmosphere without going through water or hitting a firmament.
The Catholic Church chose this hill because they didn’t actually go after Galileo because he contradicted the Bible. That was their excuse. They went after Galileo because he contradicted Aristotle, who they had accepted as their ultimate scientific authority. In fact, what really annoyed them is that Galileo had written a dialogue to defend heliocentrism and gave the dumb geocentric character who gets proven foolish the name Simplicio. While Galileo claimed “Simplicio” was supposed to refer back to the Aristotelian philosopher Simplicius, it was also a very obvious pun on the Italian word for simpleton. Hence, when they imprisoned Galileo, they also banned his dialogue (and any book he’d write thereafter).
How exactly the Catholic Church ended up venerating Aristotle, a Greek man who lived more than 300 years before the birth of Christ and was definitely not a Christian, is a long story. The short version is that Aristotle’s works went from influencing the Greeks, to the Byzantines, to the Islamic scientists, to the Catholic Scholastics, at which point the Catholics were desperate to establish their own tradition of philosophy and decided to basically canonize Aristotle as “the Philosopher”. The Catholics, in trying to get themselves on firm philosophical footing, ended up treating Greek philosophy like a religion, memorizing it and defending it overly vigorously.
Now, to be fair to the Catholic Church, the Catholic Church of the 1600s was not the same as the Catholic Church of the Scholastics during the 1200s. So, while they did feel it was necessary to imprison Galileo, their arguments were more sophisticated than just pointing to Aristotelian or even Biblical text. They also defended the heliocentric position with physical and mathematical arguments, including Tyco Brahe’s point that heliocentrism would require the stars to be way, way larger than the Sun. And, also to be fair to the Catholic Church, the evidence at the time did not definitively point to heliocentrism, and heliocentrism, like geocentrism, required assumptions that were not justified given the knowledge of the time.
But the fact remains that the Catholic Church thought it was so necessary to prove Aristotle right that they were willing to imprison one of the great scientists of their time. How weird is that? Not the imprisoning him part. Even in the United States in the year 2023, we are no stranger to the legal system getting involved in science.
No, the weird part is that Aristotle had an influence on science at all in 1616 AD. Aristotle died in 322 BC. It had been almost 2000 years. Can you imagine a scientist 2000 years ago having an impact on scientific discussions today? Could you imagine a modern scientific paper seriously citing a scientist from 23 AD?
No, of course not. In my own work, I rarely see citations from earlier than the year 2000. When I do, I’m usually mistrustful of them, because I assume there’s a higher chance of the work being done sloppily or at least not having been replicated. In fact, my default assumption is that new work is more trustworthy than old work, all else being equal.
And that’s true of all of us. We’re all generally looking for the newest study, or the most up-to-date review. At the very least, we certainly aren’t looking through ancient texts for scientific truths.
This might seem obvious to you. Of course you’d never look at an old paper. That old paper was probably done with worse instruments and worse methods. Just because something’s old or was written by someone whose name you recognize doesn’t mean that it’s truthful.
But why is it obvious to you? Because you live in a world that philosophy built. The standards for truth that you imbibed as a child are not natural standards of truth. If you had been an educated person in 1200s Europe, your standard for truth would have been what has stood the test of time. You would have lived among the ruins of Rome and studied the anatomy texts of the Greek, known that your society could produce neither of those, and concluded that they knew something that your society could not. Your best hope would then be to simply copy them as best as possible.
This was less true by the time Galileo was alive. This is why an educated man like Galileo would have entertained the idea that he knew better than the ancient Greeks, and why his ideas found some purchase among his fellow academicians (including the then Pope, actually). But still, there was a prominent train of thought that promoted the idea that a citation from Aristotle was worth more than a direct observation from a telescope.
But you live in a different world now. You live in a world in which the science of tomorrow is better than the science of today, and our societal capabilities advance every year. We can build everything the ancients did and stuff they never even imagined possible. So you respect tradition less, and respect what is actually measured most accurately in the physical world more.
Today, this battle over truth is so far in the past that we don’t even know it was ever a battle. The closest we come to this line of reasoning is when new age medicine appeals to “ancient wisdom”, but even they feel compelled to quote studies. Even more modern battles are mostly settled, like the importance of randomized, double-blinded controlled studies over non-randomized, non-controlled studies1.
The reason we mark battles is not just for fun or historical curiosity. It’s to remind us that what we take for granted was actually fought for by generations before us. And, it’s to make sure that we know the importance of teaching these lessons so thoroughly that future generations take them for granted as well. A world in which nobody would dream of established theory overturning actual empirical evidence is a better world than the one that Galileo lived in.
The importance of randomized, double-blinded, controlled studies is another example of something that’s still counter-intuitive for most people, though. I can’t tell you how many medical papers I read that are still comparing two groups in a post hoc study (e.g. a group that got a surgical intervention vs. a group that got a therapeutic intervention), never considering that there might have been a prior reason why the groups were treated differently. And they certainly would never, ever consider that differential, post-intervention treatment by the clinicians of the two groups could possibly explain any of the differences in outcomes. Why, differential post-intervention treatment would be unethical!