"Any spell is intellectually interesting so intellectual interest doesn't count. It's admittedly pretty subjective but if you come of age a Legilimens and knowing the Unforgivables and I'm presuming here there are also things he hasn't admitted to in two hours of casual conversation - that meets common usage - uh ,and world conquest is considered a sort of Dark ambition though that's mostly just because the people who try it keep being evil -"

"The world is really badly run. If it were nicer I bet I'd only be a tiny bit tempted to rule it."

"How much nicer?"

"...really, really nice, admittedly."

Snort. "I'm not sure why world conquest is so popular among the evil."

"With wizards I think part of the problem is that if you're insufficiently paranoid you never get anywhere and if you're sufficiently paranoid you know lots and lots of really evil magic and might be tempted to make exceptions on the not using it."

"That'd be a fairly satisfying explanation if it were only wizards we were explaining."

"I haven't actually paid much attention to Muggle would-be rulers of the world, do they actually suck more than, like, the typical person?"

"Possibly only insofar as they acquire opportunity, I suppose."

"Most people are kind of terrible. - oh, your demon acquaintance laughed at me for suggesting a model size in cubits, the world I take it having picked different units of measure, and I didn't actually look whether it was our or Revelation's -"

"She was expecting meters - I would've warned you to go metric if you were American but I confess cubits did not occur to me, they are sufficiently obscure to qualify as a Bible reference even without further clues because one only hears about them for Ark reasons."

"I have never heard of a meter."

"One ten-millionth the distance between the equator and the North Pole. The French came up with it. We use that?"

"I still have no idea how far that is."

He makes an effort to gesture at approximately the right length without letting go of his book. "They came up with it a couple years ago, I remember reading something about it."

"Everybody uses that, the United States held out with feet and miles and whatnot till well after my death but eventually standardized, you guys switched earlier than that."

"Well. Timothy's going to take over the world so he can pick the units and he doesn't have to pick French ones."

"It'd be convenient to be able to trade with Revelation, though. And copy their stuff without converting units."

"The argument for metric is everything is powers of ten and there are convenient equivalencies like a cubic centimeter being a milliliter. The argument for Imperial - though it did not in my lifetime include cubits - is that it's better for measurements of human-scale things like the weather in places people live or human heights."

"You can pick, kiddo."

"That's no fair, if it actually matters I can't just be prejudiced."

"Yeah, exactly."

"Something wrong with France?"

"Well, it's kind of in the middle of a horribly bloody civil war, there's that. And also my grandfather's second wife is from there but it is unfair to blame the country for her, if you think about it they really got rid of her as fast as they could."

"So that matches, does it."