"It's 'cause spells are subtly different because people think about and relate to them differently. Like—I think I mentioned my read-while-invisible spell, when I don't fill in every little gap in defining the effect it makes invisible books readable by making every letter on the page identifiable but things like colour aren't, and someone else binding a similar spell might get something like meanings embedded on the paper or something different depending on what they think of as 'reading' and 'visible while invisible' and what-have-you."

"Is that brain architecture per se or just how they think about things? Can it change over time per person?"

"I'm not sure, I've never been around anyone long enough to figure that out, but I've never met two people with the same—whatever-it-is. I'm not sure there's a meaningful distinction here between what I'm describing as how they think about things and architecture?"

"Hmmm. Do you know what causes people in your world to have various magic?"

"Seems to be random, why?"

"No, no, random is who it happens to, I mean how."

"Oh. Far as I know they're just born with it? I don't know of any mechanism, some people just generate mana."

"Hrmph."

"Why, did you have any ideas...?"

"I was wondering if it ran in families or something."

"Oh it doesn't. Lots of people believe it does, our succession laws are based on that assumption, but the data disagree."

"...how do the succession laws not collapse, if it doesn't?"

"Well, the succession laws permit you to rule without being a mage if you marry someone who is a mage of the appropriate kind. Also people pretend a lot. And the courts are large enough that every age group tends to have a couple of real mages of the relevant kinds."

"People can pretend? They never have to demonstrate?"

"Sometimes, but if you hire an arcanist to do things for you, or an enchanter, or whatever, you can go a long way. And the situations where they'd have to demonstrate are very rare—doing magic has religious connotations, it's supposedly a gift from the gods and shouldn't be used casually. Of course, every now and then someone is found out and then excommunicated for pretending."

"...casually meaning?"

"Like, doing it to help other people is okay, doing it as part of your job is okay, doing it for research is okay, doing it to fight is okay, doing it to reach for the jar on the very tall shelf is not okay, doing it to show off is extra not okay."

"That's stupid."

He shrugs. "Extremely so."

"I'd still expect them to get into situations where they could if they had the magic help somebody or get into a fight with it."

"There are some like that, but refusing to use magic is never bad per se, it's better to not risk committing blasphemy than acting when uncertain."

"There are a couple religions that don't like magic, here, but I can't think of any that handle it like that."

"Yeah, it's rather interesting from a sociological standpoint but unfortunately I live in it."

"Not any more you don't."

"Hmm, I guess. Still, other people do, and I wanna fix it."