It was two things. First, you have to understand what was going on at the time. It was 1615 when this whole thing started, and the Catholic Church had been in the middle of a religious war for a hundred years, and the whole question behind the thing, the whole reason for the Protestant Reformation was the question of who has the right to decide how to interpret scripture. Does the Catholic Church have the exclusive right to do that, or does everyone have the right to decide it for himself?
So for a hundred years, the Catholic church was fighting this war…this battle over interpretation, and it’s been losing. Scandinavia has gone to the Protestants, northern Germany, the Netherlands, Scotland, England, all lost to the Protestants. Hungary, Poland, France, all weak, all riddled with Protestants, all battlegrounds. And the Catholic Church is fighting a rearguard action. Just 20 years ago, it finished the Council of Trent, it’s restarted the Inquisition, it’s starting to fight back. But it’s still scared; its still beleaguered. Now you’ve got Galileo coming around, and he’s saying, “The Catholic Church is wrong when it interprets scripture to say the sun moves around the earth.” He’s doing what the Protestants are doing; he’s threatening the authority of the Church, so the Church has to slap him down. It’s not about heliocentrism or geocentrism. It’s about us saying what scripture means, Galileo, not you. And so they put him on trial and slap him down.
So then time passes, and Urban becomes pope, and Galileo thinks this is great news, because Urban is a scientist and patron of the sciences, and he and Galileo have corresponded…they’re almost friends. But Urban has his own problems. He’s constantly fighting the Italians and the Romans to extend his power and his family’s power. And he’s being threatened…there are plots against his life, and he’s scared. He’s insecure about his power, and is always trying to shape his image. And, he’s a geocentrist. He’s pretty publicly a geocentrist…he’s even written about it. So Galileo publishes his “Dialogue on the Two World Systems”, where he says he’s going to lay out the arguments for both. But he doesn’t. He puts the geocentric position in the mouth of the character Simplisicus…Simpleton. And he makes Simplisicus an idiot. And the arguments he puts in the Simpleton’s mouth are Urban’s arguments. Sometimes they’re direct quotes. Galileo has just publicly mocked the pope, in print. He’s called him an idiot, and he’s called everyone who believes in geocentrism an idiot. So the pope has to respond. He’s insulted, for one thing. Here’s a guy who he thought was his friend, publicly calling him an idiot. And besides, even if it wasn’t for the personal betrayal, he’s the Pope. If he doesn’t do anything, he’ll look weak. And if he looks weak, his enemies in Rome, his enemies in Italy, his enemies in Europe will destroy him.
It’s not about heliocentrism or geocentrism. It’s not even about “paganizing” or “depaganizing” (that was a Protestant buzzword, btw…“We have to depaganize the Church, we have to restore it to “true” Christianity”). It was about power and politics and hurt feelings and Galileo’s constant ability to insult anyone who disagreed with him on anything.