Skarpi (Name of the Wind) and Felurian (Wise Man's Fear) both say the Creation War happened so long ago that history has forgotten it. The Cthaeh says to Kvothe that "Haliax has been alive five thousand years," implying that the Creation War took place around 5000 years before the book's events. How is it that nothing from that era is remembered? In real life, we at least know of the existence of ancient Egyptian, Chinese, Mesopotamian, etc. civilizations, even though they existed around 7000 years or more ago. Kvothe even finds massive ruined structures underneath the University. Do archaeologists not exist in the Four Corners?
The Adem don't know that sexual intercourse causes pregnancy because they have so much sex that no one never linked the two. However, they do practice animal husbandry. Wouldn't that have clued them in? Without selective breeding, they would not be able to domesticate their livestock. All of their animal products, like meat, leather and wool, would be inferior to those outside their borders.
Kvothe makes the comparison to cats, and the woman in question points out that humans and cats are not the same—which Kvothe admits is true, he was using a fallacy. They just think they're different that way. After all, humans don't give birth in litters either.
The Adem don't believe that animals reproduce through sexual intercourse either. They believe that sex has nothing to do with reproduction. They don't even have a word for father. If they did conceed that animals reproduce sexually, just not humans, then the argument would have been much different. The culture would also have a word for father, because they'd need to use it for animals.
I wonder if there's something resembling celibacy in the Four Corners. Granted, the Adem probably wouldn't believe Kvothe something like that exists, but the general idea that celibate women don't get pregnant is quite hard to counter.
Patrick actually answered this:
Fan Questioner: Have you read about the Trobriand Islanders, the matriarchal society whose diet serves as birth control for the population? PR:Yup. Fan Questioner:Did you deliberately choose recessive traits for the Adem peopleís general appearance? PR: Yup. Because Iím awesome.
As you can see in both the fictional and real society matriarchal mothers pass along the secret of a child bearing diet completely controlling reproduction.
Adem women secretly controlling their pregnancies through diet is never even hinted at in the books. That would be a pretty major lie at the center of their society. Also, as I recall, the only cook we meet in Four Corners is a man. How do Adem women secretly control their diet when there are men making their food? Also, Adem women spend a lot of time away from their homeland fighting. How do they maintain a contraceptive diet when food resources are limited? Also, none of this addresses my previous concern that animal husbandry reveals the link between sexual intercourse and pregnancy.
The Adem don't have sex outside their own society, since they're afraid of STD's. The most likely possibility is that the contraceptives are a naturally occurring part of their diet, some herb they use to spice their foods, not a vast conspiracy. Still not sure about animals, but maybe they're affected by the contraceptive too, so the Adem don't really have animal husbandry? Been a while since I read the book, so I don't recall how much detail was given there.