"Well, uh, it's . . ." He thought about it for a moment. "There's probably a proper definition, isn't there? It's not just disagreeing with the Church, is it?"

"Actually, that's rather close to what the real definition is, if the ugly truth be told. It's like this, and I'm simplifying here, you understand?"

Frank nodded.

"The Church is in the business of guiding people to Jesus, right?"

Nod.

"And, for an assortment of reasons that seem good to us, we have a whole hierarchy set up to decide the best way to go about it, yes?"

Nod. Frank wasn't sure he got it, but this probably wasn't the best time to pick an argument he wouldn't know how to conduct, let alone win.

"And, again, for an assortment of reasons we think are good ones, the Church gets the last word with Catholics about what we ought to believe. That's supposed to be one of the big differences between us and Protestants, by the way. They're supposed to believe that it's really down to each man with Scripture and his faith to find his best way to God. If the Reverend Jones were here right now, which he's not, he'd be correcting me six ways from Sunday on the subject, but that's about the theoretical size of it. I don't suppose you followed the Rudolstadt Colloquy?"

"The what?" Frank knew where Rudolstadt was, but-no, hold on, now he remembered something. "Wasn't there some kind of big conference there last year?"

"Indeed there was. A big argument between one lot of Lutherans and another lot of Lutherans about what kind of-but I'm getting off the point, here. A good few of the speakers at that conference reckoned that they were the last word on what a Christian ought to believe as well, and don't think for a minute that I'm taking advantage of Simon's absence to make a few cheap cracks at the expense of the competition." Mazzare smiled broadly.

The smile was infectious, and Frank found himself chuckling. "So where you've got one pope, they've got a whole bunch of 'em?"

"Oh, that's good," said Mazzare, "I'll have to remember that the next time I get Simon going on this topic, I really will. And it's sort of accurate, too, although they do deny it. It's why you get lots and lots of little Protestant churches. I mean, there's something to be said for it, they're all Christians at heart and it must be easier knowing you can just head on down the road if you lose an argument."

Frank got the feeling he was getting a look in on an old, old, argument.

Mazzare sighed. "I shouldn't just sit here and slam the competition, should I? I was talking about heresy, and Galileo. Anyway, the formal definition of heresy goes something like this: 'the obstinate denial, after baptism, of some truth which must be believed with divine and catholic faith.' There's a bit in it about obstinate doubt, as well, but I'm not going to subject you to a lecture on formal theology. The thing is, there's a difference between proposing a subject for debate and deliberately expressing denial, you see, and Galileo got himself on the wrong side of that difference."

"But he was right . . ." Frank was wondering where this was leading.

"Yes, well, we knew that by the twentieth century. Actually, we knew it by the eighteenth as it happens, and Church teaching changed."

"I thought dogma couldn't-" Frank grinned. "You're going to explain it to me, aren't you?"

Mazzare's smile was still on his face "I'm carefully not using words like dogma and doctrine and faith and so on, you know. They're actually bits of theological jargon, with subtle shades of meaning. Let's stick with teaching. You know that if you want to be a Catholic, you have to believe the same things that all the other Catholics believe? I think we established that."

Frank nodded. He'd heard some of the things Christians believed, and figured they had some nerve calling his dad a weirdo for what he believed in. At least Tom Stone didn't claim to be smoking the body of Christ when he lit up a joint.

"Well," Mazzare continued, "in the time we came from, if you stop believing what all the other Catholics believe, you just stop being a Catholic. That's sad but it happens. In theory, at least. There're are some fairly out-there Catholics in the twentieth century. But I digress. Here and now, if you stop believing what other Catholics believe, it's a crime. Heresy both ways, but different ways of dealing with it."

Mazzare stopped to heave a big sigh. "That's Galileo's problem right there. He disagrees with the Church about what Catholics ought to believe about the shape of the world. Now, the pope told him-back when he was plain old Cardinal Maffeo Barberini, I think, although I could be wrong about that date-"

"What, he personally told him?" That sounded odd, to Frank. He'd picked up enough about how the seventeenth century worked to know that who you knew was very, very important indeed.

"Oh, yes. Galileo and the pope are actually old friends. Or they were, at least."

"So how come the pope sicced the Inquisition on him?" This wasn't following the script that Frank was expecting.

"Well, it was more a question of not being able to stop it, or not easily, anyway. I've only gotten this from a book we have back in Grantville, you understand, that was made up of translations of all the papers about Galileo's trial that survived to the twentieth century, plus a book about Galileo's daughter. And, I have to confess, I last read up on the whole thing a while before I went to Grantville because I did a stint as a university chaplain and I got into arguments with scientists about it." Mazzare chuckled. "Actually, I used to really annoy them by pointing out that Galileo got caught by politics, and it was Protestants who suppressed the work of Copernicus and Kepler purely on the strength of it being contrary to Scripture."

"Who and who?" Frank asked.

"Oh, Copernicus was the Catholic priest who first discovered that the Earth orbits the sun, and Kepler was the one who figured out the laws of orbital mechanics. He died only a few years ago, as it happens. But I'm wandering off the point again."

"You say Galileo got caught by politics?"

"Yes. I said before that everyone thinks of it as a plucky scientist battling against the medieval darkness, but it's not that simple. To start with, as I said, Galileo used to be friends with the pope."

Frank heard where Mazzare put the stress on the words, and took his cue. "Used to be?"

Mazzare grinned. "Right up to when Galileo called the pope a simpleton in print."

Frank couldn't think of anything to say.

"Oh, not in so many words," Mazzare added, "but he took every opinion the pope ever expressed on the subjects of science and astronomy and put them into the mouth of a character called Simplicio. Now, at his trial-as I recall-he claimed that was supposed to be Simplicius, a philosopher from classical times. Thing is, he wrote it in Italian, and in Italian, Simplicio means . . ." He pointed to Frank.

"Simpleton. So the pope's really ticked off, huh?"

Mazzare wiggled his hand back and forth. "Hard to know, really. Urban VIII is a very sophisticated man, by all accounts. Not the type to fly into a rage over a minor personal insult-especially since he could, after all, choose to accept Galileo's excuse. Anyway, just to make his own life more interesting, Galileo published his book in Italian, like I say. So he couldn't claim that he was trying to start a learned debate, he'd written for the popular market. Even so, if he could have proven it, he'd have been fine. After all, if nature says one thing and the Church's teaching says another, the Church's teaching has to be wrong and the teaching has to be changed, right?"

"They can do that?" Frank asked.

"We can and we do, Frank. The thing is, a couple of places in the Bible, it talks about the sun going around the Earth. Now, you can read that as a description of what really is going on, or you can read it as the guy who wrote the words down saying what it looked like."

"And the Church is saying that's what it really is, right?" Frank was following the logic, now.

"That's about the size of it. And Galileo couldn't prove otherwise, you see. Part of that was that the astronomer who had the best evidence for the theory he was trying to prove was one of the many people Galileo had annoyed over the years. In fact, he'd denounced the evidence as fraudulent."

"What was it?" Frank was actually getting really interested, now.

"It was a comet, as I recall. Scheiner, who's in Rome right now, or it might have been Grassi, another of the Church's astronomers, I can't remember-"

"The Church has astronomers?"

"Sure. Most of the leading astronomers in this day and age are actually Catholic priests. Did you run into Father Kircher at the high school?"

"He's an astronomer?"

"Among other things, yes. He does just about everything; a very bright man. But as I say, there are these two Church astronomers who've got the evidence that goes a long way to prove what Galileo was saying."

"Then why don't they, I mean why didn't they come forward with it? Didn't they want to get accused of heresy too?"

Mazzare laughed. "This is why I said it was more complicated than everyone thinks. They published it, years ago. And Galileo called them both frauds. Galileo thinks comets are optical illusions in the upper atmosphere."

"He thinks what?" That didn't sound like the Galileo he'd heard about.

"Oh, yes. A lot of Galileo's 'science' was off-base. He came up with a wrong explanation for the tides, too. To make things worse, he's a notorious intellectual bully who rarely sees the need for common politeness. Take Scheiner and Grassi: he called one of them a drunk and the other one a plagiarist. Which is why they, between them, reported Galileo to the Inquisition when he published his last book. In which, as I say, he called the pope a simpleton."

Frank mulled over that for a moment. "Can't we send some astronomy textbooks to Rome, or something? If Galileo can prove it, he gets off, right?"