Nod. Sigh. "A religious prohibition on birth control...what if you literally can't feed another kid, what if you're sick and shouldn't be pregnant..."

"They can refrain from sex. Breastfeeding also has an unreliable contraceptive effect and that's fine. Also, like, this was mostly an academic theological question, for Muggles, until recently."

Nod. Sigh. 

"Is this useful for anything? Can I arrange for Rebecca to be present in situations that would result if he did things we don't like?"

"Might help if he's doing them for not-worth-the-expenditure-of-political-capital reasons, probably would just get you a sad Aitim if you tried it on something like the population controls where how he feels about it hasn't really got anything to do with it."

"Pity those are a sticking point."

"Yeah, if you make him pick between 'cause a war' and 'cause a different war' then I don't know how he picks but who'll be sad in his vicinity isn't it."

"That's good, I guess."

"I guess it would be really irresponsible."

"Yeah."

"Weren't humans already at the stage where they were expanding and murdering the locals to give themselves more space to settle?"

"This isn't because of underlying land carrying capacity in most cases. We're not living anywhere nearly as densely as we could be even on our preexisting tech level. People just run into other people and don't get along and fight. Reasons people go live in other places in the first place include religious oppression, there being a really big island used as a prison colony, wanting to see what's there, trying to make money off what's there... not 'there literally isn't anywhere to live hereabouts'."

"Doesn't have to be 'nowhere to live', can also be 'can't afford to keep the farm' or 'can't afford to feed the family'... we have a lot of space but if we had a lot more people then food would be really expensive, and having to work for most of a day to afford your food for the day is a very bad place to be in."

"There's some of that but I don't think it's carrying capacity at tech level I think it's how the economy's structured. The city Aitim lives in looks out on undeveloped forest as a sort of statement. There's a lot of that, even in places that have been settled for thousands of years, just - space."

"It makes sense to not want controls until you're at thirteen billion like us."

"Hala thinks that in a few generations we'll stagnate or even decline. The generations would be to decrease religiosity and suchlike."

"Why would religiosity decrease? Particularly while it's being aggressively selected for?"

"Education. Wizards are negligibly religious. Also I'm not sure it's particularly genetic."

"As long as it's heritable, if religious people have ten kids and three of them stick with the religion to have ten of their own your religious population is growing."

"The irreligious population grows faster and has more cultural dominance, if it's three and seven, so soon it's two and eight, etcetera."

"Cultural dominance can be a very local thing. Also sometimes people are likelier to stick with something they perceive as under threat. Also if instead it's five and five - or if it is genetic even a little bit..."

Shrug. "Hala thinks you could drive us extinct by accident."

"Well, she has more data than me, but 'without religion, below replacement' and 'with religion, want fourteen' doesn't obviously suggest any specific trajectory."

"Aitim's running a trial program where he coaxes people into delaying marriage, which is pretty religiously acceptable."

Nod.