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Long ago I read "essai de prospective demographique"[1] written by French demographers. They were raising the concerns you mention and were trying to warn the

Long ago I read "essai de prospective demographique"[1] written by French demographers. They were raising the concerns you mention and were trying to warn the public of a coming "demographic winter". So your point of view is not rare. That being said, even if a demographic winter would probably have very adverse consequences, as it is not clear how well the industrialized society would fare if the population was drastically reduced, I have hard time picturing how that could lead to the complete extinction of mankind. There will always be pockets of population with high fertility, at the very least among highly religious communities. Even if as you suggest reproductive behavior is transmitted, that works both ways, and simple natural selection will always, in the end, favor the reproductive behavior that leads to increasing numbers. Demographic winter is a serious concern, but I can't imagine it leading to a complete extinction. 1. https://books.google.fr/books/about/Essai_de_prospective_d%C3%A9mographique.html?id=lz9mPQAACAAJ&hl=fr https://books.google.fr/books/about/Essai_de_prospective_d%C...

NoMoreNicksLeft 11y ago
> There will always be pockets of population with high fertility, What makes you say that? Is there some underlying principle I've failed to consider? > I have hard time picturing how that could lead to the complete extinction of mankind. It's simple math. Below-replacement fertility leads to extinction. More people die than are born, and since the original number is finite, the end number must be zero. If you think that will not happen, what you're imagining is that the fertility rate will either rise at some point in the future, or at least plateau at whatever number leads to a stable population. Why would they rise? If you grow up in a world where everyone around you has few children, then you grow up thinking/feeling that few children is the way things should be. You have few yourself. You might even have fewer than your parents' generation... but you'll rarely if ever have more. On average, you'll never have more. Even in the fertility hot spots, this is true. They're above replacement fertility still, but each generation has a lower number. It's not exactly some sort of hidden trend, it's pretty basic. > at the very least among highly religious communities. It looks like the children of these communities break away from their religious upbringing at a higher rate than their pious siblings can replace with nephews and nieces. Especially in those religious communities that are unable to achieve a healthy economy... the FLDS communes that dispose of their sons, the ultraorthodox jews in their own self-imposed ghettos where there is little employment to be had. > Even if as you suggest reproductive behavior is transmitted, That's a little silly of me, actually. It must be the one behavior pattern that isn't transmissible. > and simple natural selection will always, in the end, favor the reproductive behavior The natural universe has no favorites. It does not preclude this sort of extinction. Those few who buck this trend will be starved for adequate mates at some point, and will raise their own children in a culture that ostracizes fertility...
- grondilu 11y ago
  > What makes you say that? Is there some underlying principle I've failed to consider? Low fertility rates is a statistical rule. It's not absolute. There will always be people with high fertility, at the very least because they will be at the edge of the bell curve. Also again, look at religious communities, like the Amish. Those people do exist. Among seven billion human beings, you certainly can find a few millions that are very much willing to make babies. It only takes a small minority to ensure that the numbers will not go to zero. > The natural universe has no favorites. It does not preclude this sort of extinction. The lineage of people who don't have children will simply disappear, leaving room for the lineage of people who do. It's as simple as that. > Why would they rise? The fertility rate will rise because people with low fertility rate will die with no children. What will remain will be the children of people with high fertility rate, and presumably those children will have a similar reproductive behavior than their parents. Low fertility reproductive behavior will be "naturally" filtered out. > Those few who buck this trend will be starved for adequate mates at some point, and will raise their own children in a culture that ostracizes fertility... Fertility declines, but it's quite a stretch to talk about ostracization of fertility. And ostracization is not prohibition.

NoMoreNicksLeft 11y ago

> There will always be pockets of population with high fertility, What makes you say that? Is there some underlying principle I've failed to consider? > I have hard time picturing how that could lead to the complete extinction of mankind. It's simple math. Below-replacement fertility leads to extinction. More people die than are born, and since the original number is finite, the end number must be zero. If you think that will not happen, what you're imagining is that the fertility rate will either rise at some point in the future, or at least plateau at whatever number leads to a stable population. Why would they rise? If you grow up in a world where everyone around you has few children, then you grow up thinking/feeling that few children is the way things should be. You have few yourself. You might even have fewer than your parents' generation... but you'll rarely if ever have more. On average, you'll never have more. Even in the fertility hot spots, this is true. They're above replacement fertility still, but each generation has a lower number. It's not exactly some sort of hidden trend, it's pretty basic. > at the very least among highly religious communities. It looks like the children of these communities break away from their religious upbringing at a higher rate than their pious siblings can replace with nephews and nieces. Especially in those religious communities that are unable to achieve a healthy economy... the FLDS communes that dispose of their sons, the ultraorthodox jews in their own self-imposed ghettos where there is little employment to be had. > Even if as you suggest reproductive behavior is transmitted, That's a little silly of me, actually. It must be the one behavior pattern that isn't transmissible. > and simple natural selection will always, in the end, favor the reproductive behavior The natural universe has no favorites. It does not preclude this sort of extinction. Those few who buck this trend will be starved for adequate mates at some point, and will raise their own children in a culture that ostracizes fertility...

grondilu 11y ago
> What makes you say that? Is there some underlying principle I've failed to consider? Low fertility rates is a statistical rule. It's not absolute. There will always be people with high fertility, at the very least because they will be at the edge of the bell curve. Also again, look at religious communities, like the Amish. Those people do exist. Among seven billion human beings, you certainly can find a few millions that are very much willing to make babies. It only takes a small minority to ensure that the numbers will not go to zero. > The natural universe has no favorites. It does not preclude this sort of extinction. The lineage of people who don't have children will simply disappear, leaving room for the lineage of people who do. It's as simple as that. > Why would they rise? The fertility rate will rise because people with low fertility rate will die with no children. What will remain will be the children of people with high fertility rate, and presumably those children will have a similar reproductive behavior than their parents. Low fertility reproductive behavior will be "naturally" filtered out. > Those few who buck this trend will be starved for adequate mates at some point, and will raise their own children in a culture that ostracizes fertility... Fertility declines, but it's quite a stretch to talk about ostracization of fertility. And ostracization is not prohibition.