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Wednesday, August 10, 2016

Go Forth and Multiply

A couple of paragraphs in an article titled How Anti-Discrimination Became a Religion, and What It Means for Judaism caught my eye (don't ask me how I happened upon that article - I have absolutely no idea!):
As for those who remain active members of the Jewish community, they will be divided among a large but shrinking cohort of mostly Reform and other religiously liberal Jews; a smaller but vigorous group of modern and centrist Orthodox Jews joined by remnants of the rapidly declining Conservative movement; and a large and rapidly growing group of ḥaredi or “ultra-Orthodox” Jews. 
At some point, indeed, this last-named group, whose current rate of per-year population growth stands at an astonishing 5.5-percent, will form a significant element of the public “face” of American Jewry.
Before I get to my main point, I first have to point out that even though I'm jewish through ancestry (though non-practicing), ultra-orthodox Jews are as strange and exotic to me as the Amish or Tibetan monks or something like that. For example, if, for some reason, I suddenly decided that I needed to go to some sort of religious service, while my first choice would be a Reform Jewish service, I'd much rather go to, oh, I dunno, let's say a Methodist service or something like that, rather than an ultra-Orthodox Jewish service.

As far as I can tell, the ultra-Orthodox could never really be the "face" or in any way representative of all American Jews. Or, at least, I rather hope not.

But there is that population growth thing to consider. 5.5 percent per year really is astonishing (basically more than doubling every generation and amounts to over 6 children per woman on average) and if maintained, would indeed eclipse the rest of the shrinking American Jewish population in just a handful of generations.

What really caught my attention, though, was how well this real-life scenario potentially fits the population simulations I did a while back:
The simulation is fairly simple. Start with a population of 1,000,000,000 people. There are two types of "genes" in this population. The most common and also dominant gene is the "barren gene" and compels its individual to produce one child on average. Given that it takes two parents to produce a child, if this were the only "gene," the population would halve every generation and mankind would indeed go extinct in only a few hundred years.

The second "gene" is the "fruitful gene" and potentially compels its individual to have three children on average. However, since this "gene" is recessive, the individual is only compelled to have three children if he or she has two of these "genes." At the start of the simulation, only five-percent of the genes are of this type. So not only is it recessive, it's also rare. If a double "fruitful" mates with a someone with at least one "barren gene", they split the difference and have two children.
This very pessimistic simulation shows the population dropping fairly precipitously for 15 to 20 generations until the "fruitfuls" finally become common enough to overwhelm the "barrens" and then the population comes roaring back in 20 to 30 generations.

Here, in real life, the non-ultra-Orthodox American Jews pretty much follow the "barren" pattern (somewhat more than one child per couple) and the ultra-Orthodox Jews are more than "fruitful" (more than 6 children per couple), at least at the moment. In addition, unlike the simulation where all mating is random making it unlikely for the rare "fruitfuls" to mate with each other until enough "barrens" have died out, the ultra-Orthodox clearly seek each other out at a far greater rate than would occur in random mating.

That's why when some folks get to hand-wringing about falling birthrates, I'm far from concerned. Some group will always be happy to go forth and multiply and be there to inherit the earth.

76 comments:

Clovis e Adri said...

Great, a good post connected to another good one.

I would add one reason for the ultra-Orthodox not to become the "face" of American Jewry is that, even though they may come to produce most of its members, the difficulty of keeping up a 'coherent population/creed' also sizes up in proportion.

IOW, as the ultra-Orthodox population grows, so does the rate of defection to other creeds.

Hey Skipper said...

[OP:] The simulation is fairly simple. Start with a population of 1,000,000,000 people. There are two types of "genes" in this population. The most common and also dominant gene is the "barren gene" and compels its individual to produce one child on average.

The second "gene" is the "fruitful gene" and potentially compels its individual to have three children on average …


Even giving the matter a great deal of thought, I can't think of a better example of question begging than this.

Naturalistic evolution will not, cannot, select for a trait that has absolutely zero survival benefit. Contrary to the simple conclusion, Barren and Fruitful would have been completely worthless. All females of all species throughout evolutionary time have reproduced to the extent allowed by the environment. There has never been any such thing as a female seal, bear, wombat, or human saying "No thanks, not tonight, or any other night for the next year. I'm feeling barren this breeding season."

And if there had been, for reasons that would conk Evolution on its noggin very hard, it would have already bred itself out of existence. And if you try to argue otherwise, then you are right back to question begging: how could it possibly be that a gene which had no effect could still perpetuate itself?

As if that isn't enough, somehow this gene's expression is isolated to certain faith traditions. (How we got to that sloppy term to describe religion, I have no idea.)

There is a great deal of explaining to be done there.

And here, too:

Since 1980, both Utah and total LDS birthrates have declined precipitously, though still remaining above total U.S. levels.

How does that work? Did the Fruitful gene suddenly go into remission?

Humanity is doing an epic evolutionary experiment. IF Fruitful and Barren do not exist — and there is absolutely no reason to presume they do — then in the blink of an eye, chemistry has given thinking animals, women, an option that has never before existed: How many children is enough?

As if that isn't enough, that question is riding on the urbanization tide, also evolutionarily unprecedented.

Presuming the existence of Barren and Fertile requires assuming they have existed despite there being no reason for their existence.

Alternatively, women, when provided the opportunity to control their fertility, and children now, instead of being a source of labor, are a huge cost, fertility rates will go below replacement.*

And stay there.



* Our Africa trip tour guide was Zimbabwean. Among many things he told us about his country, one of the most striking was, in his lifetime, the drop in family sizes from 6 children to less than 3. Given that replacement fertility is 2.1 in technologically advanced societies, three in Zimbabwe might not suffice.

Bret said...

Hey Skipper wrote: "Naturalistic evolution will not, cannot, select for a trait that has absolutely zero survival benefit."

I don't get this at all. Are you saying that evolution "will not, cannot, select for a trait" unless it's guaranteed to have "survival benefit" for all time? That a trait won't come into being if it might be detrimental in a million or billion years?

In the case of the simulation, "barren" wasn't always "barren" but for some reason the new environment made it so. For example, perhaps something like, oh, I don't know, say effective birth control, appeared in the environment. Then a trait that might've limited explosive followed by collapsing populations that would've been a good thing became a not-so-good thing as far as producing future generations goes. And a recessive "fruitful" gene would eventually come to be an important trait again.

erp said...

Bret, it happened as a kid we lived within walking distance of an Orthodox Synagogue and our next door neighbers were Orthodox Jews. They were very good friends and neighbors as were their friends and family.

If I had to put my trust in any organized group, it would be they. Straight and true, kind and caring in the extreme. Stories of their generosity and kindessess are legion.

You may want to do some research on Methodism before converting. :-)

As for birthrates, as in all things, nature will take its own course.

Hey Skipper said...

[Bret:] don't get this at all. Are you saying that evolution "will not, cannot, select for a trait" unless it's guaranteed to have "survival benefit" for all time? That a trait won't come into being if it might be detrimental in a million or billion years?

That is exactly what I'm saying.

Go back to basics. DNA randomly mutates, with indifferent, deleterious, or advantageous results. That means a theoretical Barren or Fruitful gene cannot possibly exist over long periods of time unless it does something. But that isn't what you are proposing. Rather, for Barren or Fruitful to exist, they must have remained unchanged over deep time, despite random mutations that would have eliminated them because they did nothing over deep time.


And this is no help: Then a trait that might've limited explosive followed by collapsing populations that would've been a good thing became a not-so-good thing as far as producing future generations goes.

Because I'll bet you can't find a hint of such a thing. Female reproductive biology, absent severe deprivation (e.g. when female athletes drop below about 10% body fat, they develop amenorrhea) runs like clockwork. There is precisely zero evidence for, except in extremis, anything like a trait that drives women to more or fewer children.

And the other thing to keep in mind is that Barren, if it existed, would have long since bred itself out of the population.

Why not go with the simplest explanation? Thinking female animals able to control their own biology is evolutionarily unprecedented, and that there is no reason for evolution to have already provided an answer for questions never before asked.

Birth rates sinking like greased safes the world over should be hard to ignore.

[erp:] As for birthrates, as in all things, nature will take its own course.

True. But what course will that be?

erp said...

¿Quién sabe? That's the fun part of it.

I hope you'll write a post about your African trip. What an adventure.

In fact, a book about your life experiences would be fascinating.

Bret said...

Hey Skipper wrote: "Because I'll bet you can't find a hint of such a thing. Female reproductive biology..."

Happens all over the place. Here's an example:

"How big the litter size is depends on where the coyotes live. In areas where there are a lot of coyotes, there will be a smaller litter size. In areas with fewer coyotes, the litter size will be larger. "

Hey Skipper wrote: "Birth rates sinking like greased safes the world over should be hard to ignore."

Not quite the world over, eh? That would be the point of this post and the simulation. If even one itty-bitty teensy-weeny pocket of humanity maintains more than replacement birthrates, humanity does just fine.

Bret said...

erp wrote: "You may want to do some research on Methodism before converting."

I didn't say convert. I said on the rare chance that "I needed to go to some sort of religious service" like, you know, maybe once, like, ever.

The problem with orthodox jewish services is that they're in Hebrew and my Hebrew is close to non-existent so I wouldn't understand more than a few handfuls of words they said.

erp said...

Just teasing, my dear. :-)

Hey Skipper said...

[Bret:] Happens all over the place. Here's an example:

Hmmm. Didn't know that.

Any evidence of such a thing in humans? If not, then you are still positing the continued existence of a gene that has, heretofore done nothing.

Not quite the world over, eh? That would be the point of this post and the simulation. If even one itty-bitty teensy-weeny pocket of humanity maintains more than replacement birthrates, humanity does just fine.

I thought that the point of the simulation was to show that a putative Fruitful gene would eventually, in 15-20 generations, predominate.

But you are using a cultural artifact -- a high TLF for Orthodox Jews -- as evidence for a genetic cause. Aside from the problems I've mentioned above, you are also faced with explaining how Fruitful appears only in religious communities with pronounced pro-natalist theologies. That's not so tough to explain, perhaps, but its absence everywhere else is. Also tough to explain are the plummeting Mormon birthrates I cited above. How is it that a religious community which largely intermarries has had a substantial reduction in the dual occurrence of Fruitful over a couple generations?

If, on the other hand, women have become the first procreators with a choice, then there is no need to invoke something for which there is no reason to expect to exist. (Sort of an Ockham's razor violation.) Women in particular religious communities respond to incentives in those communities just as women outside them do.

The pattern is clear: urbanization, secularization, and per-capita GDP more than $10k/year leads to sub-replacement fertility. China has virtually eliminated its one child policy, but fertility rates have hardly budged.

Your model suggested 15-20 generations before Fruitful dominated. Assume that the world converges on the US's current TLF of 1.9 around 2050 (that, roughly speaking is the UN projection).

What's the global population in 15 generations? (My guesstimate, because I'm too lazy to do the math, is humans don't breed themselves out of existence in about 200 years.)

[erp:] I hope you'll write a post about your African trip. What an adventure.

Tomorrow. Every day, tomorrow.

erp said...

Boys, remember, Man proposes, nature/god/whatever disposes. Thought for the day.

Skipper, looking forward to reading about your trip.

Bret said...

Hey Skipper wrote: "But you are using a cultural artifact..."

Note that every occurrence of "gene" or derivative in the post is in quotes. Whether, gene, meme, phenotype, doesn't much matter for the argument. Some combination will ensure that humans bear enough children to survive into the future because that combination will grow while others shrink.

Hey Skipper said...

That might be true, except that the prevalence of serious religious belief is negatively correlated with GDP, as well as all the other aspects of modern society.

Of those 5.5 children per Orthodox woman, how many are lost to secularization? If the model assumed zero, then it is bound to be optimistic; perhaps very much so.

In the article about Mormon fertility I cited above, it noted that converts to Mormonism have fertility rates no different than the populations they came from, and also noted "losses" due to secularization.

In evolutionary terms, thinking procreators are completely unprecedented; therefore, I think it a real leap of faith to assume evolution has provided an answer.

Bret said...

Hey Skipper wrote: "...thinking procreators are completely unprecedented..."

Ummm, no. Humans have been thinking procreators for many, many thousands of years and contraception is NOT a new concept. Yet somehow, there are still humans around, which by your logic should be utterly impossible.

And before you tell me the "pill" makes it different, less than 30% of fertile age women in the US use it.

Hey Skipper wrote: "I think it a real leap of faith to assume evolution has provided an answer."

For you apparently. For me it is an unbelievable fiction to think that humans will ever die out due to choosing not to procreate.

Hey Skipper said...

Ummm, no. Humans have been thinking procreators for many, many thousands of years and contraception is NOT a new concept. Yet somehow, there are still humans around, which by your logic should be utterly impossible.

I typed badly.

Until 50 years ago, women had no effective control over their fertility. Women have always had a brain, now they have complete control: that is what is evolutionarily unprecedented.

As for merely 30% of fertile age women using the pill, that is just one of many forms of female birth control. Add in Norplant, IUDs, etc. Also, women who aren't in sexual relationships have no need for birth control, so you need to strike them from the "fertile" population, because they don't count.

Regardless, plummeting birthrates in modern societies, and increasingly in less those less so, is a direct function of female autonomy. Where they have it, they don't seem to choose to have enough children to replace each generation.

Because it couldn't happen before doesn't mean it won't happen in the future when it can.

erp said...

One of the most disgraceful things in my opinion is the common use of abortion for easy and completely reliable birth control. Why should men or women take responsibility for their actions when it's so easy to visit the local PPC if to quote our president, a girl gets "caught."

Hey Skipper said...

Abortion is three syllables avoiding the obvious: murder of convenience.

Why should men or women take responsibility for their actions ...

Or treat women as something other than self propelled sex toys?

Clovis e Adri said...

Bret,

---
For you apparently. For me it is an unbelievable fiction to think that humans will ever die out due to choosing not to procreate.
---
Why? I like your model, but it is just a model. If you set the fruitful to decrease by some other function, you can easily achieve extinction, can't you?

Furthermore, if your point is solely that civilization can collapse and rebound after a few remain to freely procreate, well, you also set the bar too low.

As Skipper pointed out, "plummeting birthrates [...] is a direct function of female autonomy". And of incentives. Modern societies place many relevant incentives in the direction of no children. Why do you think it is impossible that such behavior can go on until you have a point of no return for entire societies (and their culture, heritage, etc)?


Harry Eagar said...

Not in Russia.

As so often among amateurs this discussion of evolution relies entirely on animal biology. Real evolutionists study plants, too, and what Bret posted does not apply even almost to many plants.

And besides, it isn't births that count but survival to reproductive status, which Skipper seemed to be approaching in his remark about replacement levels in Zimbabwe. (Think of oysters)

Women who average 6 children have not, until recently, had as many surviving reproducing offspring as women today with 1.2 (or whatever) children.

Hey Skipper said...

[harry:] As so often among amateurs this discussion of evolution relies entirely on animal biology.

In as much as this discussion centers on animal biology, I am singularly mystified as to what including plant biology could possibly add, no matter how professionally done.

And besides, it isn't births that count but survival to reproductive status, which Skipper seemed to be approaching in his remark about replacement levels in Zimbabwe.

One of the cites above (I think) cites the variation in replacement level TLF. It ranges from 2.1 in advanced societies to 3.4 in most of Africa.

Women who average 6 children have not, until recently, had as many surviving reproducing offspring as women today with 1.2 (or whatever) children.

That cannot possibly be within shouting distance of true -- do the math.

Hey Skipper said...

[Clovis:] Why? I like your model, but it is just a model. If you set the fruitful to decrease by some other function, you can easily achieve extinction, can't you?

Kind of like global warming models.

As Skipper pointed out, "plummeting birthrates [...] is a direct function of female autonomy". And of incentives. Modern societies place many relevant incentives in the direction of no children.

Mostly as an artifact of modernity, but sometimes as a matter of policy; e.g., China's one child policy. What is striking, though, is that subsequent natalist policies don't seem to move the needle much, if at all.

Harry Eagar said...

'That cannot possibly be within shouting distance of true'

Sure it can.The cities were a sink of depopulation, ever renewed from the countryside.

It could not be true for the entire species but evolution operates, most of the time, on subpopulations.

Bret said...

Clovis asks: "Why do you think it is impossible that such behavior can go on until you have a point of no return for entire societies (and their culture, heritage, etc)?"

I'm sure that entire societies can and will die completely out.

That's rather different than homo sapiens becoming extinct and no, I don't think that bar is too low.

For example, one model is that IQ will drop on average by 50 points over the next 500 to 1,000 years as the population drops to where the average human is an imbecile (but still human). Intelligent women have a reason to desire autonomy. Much less so for unintelligent women with IQ of 50 who aren't going to have much of an intellectual life or interesting career anyway. In addition, they're not going to have the focus to reliably take birth control or seek abortions and why would they want to anyway. In this model "barren" and "intelligent" are closely related traits and this does seem related to empirical evidence (or at least not contradicted by empirical evidence).

Hey Skipper said...

[harry:] Women who average 6 children have not, until recently, had as many surviving reproducing offspring as women today with 1.2 (or whatever) children.

That, as stated, is mathematically impossible.

This: Sure it can.The cities were a sink of depopulation, ever renewed from the countryside.

Is no improvement. People moved to cities because conditions there, as deplorable as they might be to our eyes, better than in the country. So your assertion that they "were a sink of depopulation" is, absent evidence to the contrary, questionable. At best.

And evidence to the contrary appears absent. Cairo: The average life expectancy is 60 to 65 for males, and 63 to 68 for females. The crude birth rate is 30.6 per 1000 people, and the crude death rate is 7.3 per 1000 people.

I got tired of looking for reliable numbers for other third world cities. Do you have any evidence for your assertion that "Cities were a sink of depopulation"?

Hey Skipper said...

[Bret:] For example, one model is that IQ will drop on average by 50 points over the next 500 to 1,000 years as the population drops to where the average human is an imbecile (but still human).

Which one model?

It seems that there should be evidence of this already. After all, the US fertility rate has been dropping for decades, and must be, according to the model, skewing towards the less intelligent.

However, The Flynn effect says otherwise.

Bret said...

Hey Skipper,

You have it backwards. IQs are increasing (it's flattened now though), fertility is dropping. Now it will turn the corner, the smart "barren" will die out leaving "fruitful" imbeciles. Fertility rate IS negatively correlated with intelligence.

erp said...

Bret, you are right of course.

Why not a federal program for all men and women with IQ's over, let's not go nuts, 125. They should be forced to freeze their eggs and sperm and then be neutered and bunches of embryos created to be implanted into the imbecile women. As time goes by, the cut off IQ would have to be raised as high as the new geniuses want and of course, there being no more imbeciles, the lower end of the IQ would have to be raised as well until everyone in the world was as smart as Obama.

OH BRAVE NEW WORLD!

Imbecile men would, of course, be castrated at puberty, heck why wait, at birth will do nicely. They would serve as manual laborers and solve three pressing problems, the difficulty in finding reliable yard help, mindless violence and the creation of more imbeciles. The danger will be when the imbeciles' IQ's start climbing and they start learning to think. Then we'll have a second Garden of Eden dilemma.

As Archie Bunker might say, Mister, we could use a woman like Margaret Sanger again!

On second thought, best to let Mother Nature sort it out.

Clovis e Adri said...

LOL. Well done, Erp.

---
For example, one model is that IQ will drop on average by 50 points over the next 500 to 1,000 years [...]
You have it backwards. IQs are increasing (it's flattened now though), fertility is dropping. Now it will turn the corner, the smart "barren" will die out leaving "fruitful" imbeciles. Fertility rate IS negatively correlated with intelligence.
---

Now that's preposterous, isn't it? Confronted with evidence, you just give us such a remarkable prediciton from some undisclosed model: 50 points? Wow.

So here is an anecdotal observation I have made myself these days: when I was a kid, to play RPG or chess was considered a thing for nerds - supposedly smart but clueless boys from middle class (and higher) background.

Poor kids, supposedly coming from fertile dumb poor mothers, would only play soccer and fuss around the block.

The other day I was at a McDonalds (at one of the most expensive spots of the city) and two of his workers (at their 18 years old at maximum) were at their lunch time in a table. They were playing RPG. I took notice because they would never be the ones playing RPG when I was a kid - their faces surely fit the poor boy image of my days (you know, in Brazil it is so easy to recognize class), but they were playing a game that asked for a bit more of non-locomotive synapses (and English knowledge) than soccer.

One such observation means nothing, but just this monday I was at a Burger King (yeah, I do like trash food, don't I?) and there again, I see two young employees, in their lunchtime, playing chess through their smartphones. When I was a kid, I never met a poor boy who could play chess.


I don't think our biological models of animal evolution can truly take in account human behavior in the long run. The joke is on the ones who think themselves to be smart enough to judge who (or what) is smart in the long run. For example, I can also bet that a society made of geniuses - devoid of 'fertible imbeciles' - would die prety quickly. Geniuses are usually the most imbecile people I know around.

erp said...

Clovis, for such a young kid, you sure are smart.

Your young gamers are exhibiting the motivational gene. They are motivated to learn the rules (probably incomprehensible to geniuses like myself), learn a foreign language and who knows what other skills needed to manipulate one of these new devil's devices running amok about the streets.

Unlike their real world where everybody on every team gets a trophy no matter how pitiful their performances, in the reality world, only winners win.

A word to the wise: Watch out for that junk food.

Bret said...

Clovis wrote: "Now that's preposterous, isn't it?"

I don't think that it matters one way or the other if examples (I did write "For example,") are "preposterous." The idea is to stimulate thought. If the concept is too much female autonomy on average to adequately procreate, then I'd bet the part of the female distribution that doesn't crave autonomy will become much more prevalent.

Skipper's hypothesis seems to be that every last female on earth will choose not to procreate. I see evidence of a wide distribution on that and the reinforcement from a survival of the fittest standpoint is that those who wish to procreate will inherit the earth.

People are different heights, different fatnesses, different levels of intelligence, etc. and to me, it's crystal clear that they also have different levels of desire to bear children. If short people suddenly had a huge evolutionary advantage, I think everybody would agree that the population would get shorter. Clearly to me, here, those interested in procreating will have an evolutionary advantage, but for some reason Skipper and others think that evolutionary pressures won't bring any change at all in the population. Ok, we'll just have to disagree then.

Harry Eagar said...

'Do you have any evidence for your assertion that "Cities were a sink of depopulation"?'

So you cite present-day Cairo where conditions have changed over the past century of public health administration. Look around when you fly. Do you go into an cities with a population of 10 million or more? You do.

Now, where were those big cities in 1800?

Bret said...

Hey Skipper wrote: "Do you have any evidence for your assertion that "Cities were a sink of depopulation"?"

Since Harry can rarely be bothered to provide a link, here's one:

http://pubs.iied.org/pdfs/10653IIED.pdf

Try googling "fertility rates urban vs rural" for more info. My understanding is that urban birth rates have been lower than rural birth rates since the beginning of humanity (sorta like the coyotes I mentioned) but that trend may be changing now.

Hey Skipper said...

A little review seems in order

[harry:] And besides, it isn't births that count but survival to reproductive status, which Skipper seemed to be approaching in his remark about replacement levels in Zimbabwe. (Think of oysters)

Women who average 6 children have not, until recently, had as many surviving reproducing offspring as women today with 1.2 (or whatever) children.


[Hey Skipper:] 'That cannot possibly be within shouting distance of true'

[Harry:] Sure it can.The cities were a sink of depopulation, ever renewed from the countryside.


So somehow we moved from a general statement, mathematically impossible, to something more specific, albeit neither clear nor prima facie valid.

What Harry seems to be saying is that [no doubt thanks to capitalism] conditions in cities were so fetid, so awful, that insufficiently many children survived to reproductive age to maintain the population. Therefore, the shortfall was made up by migration from the countryside.

That isn't necessarily false. I suppose it is possible people voluntarily to cities that were far worse than rural life. But without some evidence to support his implication, I'm inclined to think he made it up.

[Hey Skipper:] 'Do you have any evidence for your assertion that "Cities were a sink of depopulation"?'

Apparently this counts as evidence:

So you cite present-day Cairo where conditions have changed over the past century of public health administration. Look around when you fly. Do you go into an cities with a population of 10 million or more? You do.

Now, where were those big cities in 1800?


Much smaller, as was the earth's population then, which was well before urbanization got well and truly underway. I have no idea how this bears on whether "cities were a sink of depopulation", and if so, why.

[Bret:] Since Harry can rarely be bothered to provide a link, here's one:

Thanks — interesting. However, so far (I'm about halfway through) it appears to have little bearing on what you have been saying than on Harry's assertions: the demographic transition has been due in large part to urbanization. So, yes, birthrates are lower in cities than in the country, but, until relatively recently, urban birth rates were enough to not require immigration to maintain population.

Hey Skipper said...

[Bret:] If the concept is too much female autonomy on average to adequately procreate, then I'd bet the part of the female distribution that doesn't crave autonomy will become much more prevalent.

Skipper's hypothesis seems to be that every last female on earth will choose not to procreate. I see evidence of a wide distribution on that and the reinforcement from a survival of the fittest standpoint is that those who wish to procreate will inherit the earth.


Having just reviewed what I wrote, I'm at a loss for how you got to Skipper's hypothesis seems to be that every last female on earth will choose not to procreate.

No. My hypothesis is that given autonomy over their fertility, statistically speaking, women's desire for children will be satiated, on average, at somewhere between one and two children.

I am not aware of any evidence that number varies in any way based on the number of children a women's parents have had, outside of avowedly natalist religious communities that are too small, and probably have too high a defection rate to make any difference in the long run.

Something else worth keeping in mind. As I mentioned above, the Total Fertility Rate (TFR; (Here is a very interesting article on various fertility measures.) to sustain a population ranges from 2.1 in developed countries to 3.4 in places like Ghana.

Not so fast. More US women are going childless.

The percentage of U.S. women in their 30s and 40s who are childless is rising, new data from the U.S. Census Bureau show.

Some 15.3% of U.S. women aged 40 to 44 were childless in June 2014, up from 15.1% in 2012.


If most women who are childless at 40 remain so, then population replacement TFR in the US (and, by extension, all modern societies) may have been 2.1, but it is on its way to 2.3 (and perhaps even higher, because the rate of childlessness among women in their late 30's has been sharply increasing); women who never have children are, in population terms, indistinguishable from those lost to childhood mortality.

So, if women's desire for children, which for the first time they are now able to self-actualize, remains below 2, and if that desire isn't genotypic — and there's no reason for it to be — then a mixture of reproductive autonomy and modern circumstances will continue to conspire towards sub-replacement fertility, perhaps sharply so. Japan is on track to lose 30% of its population by 2070. China, 40% by 2100. And it isn't strikingly different from much of the rest of the world:

According to the United Nations, some 48% of the world’s people lives in a country where birthrates are not sufficient to sustain existing populations: All of Europe except Iceland, BRIC mainstays Brazil, Russia, and China, and even some emerging markets like Vietnam.

It seems the only sure way to stop that trend is for civilization to collapse into a pre-industrial state.

erp said...

Skipper, a nice morning analysis, thank you. :-)

Collapsing into a pre-industrial state will kill two birds with one stone as well.

All the effete lefty elites will starve to death thus eliminating the number one scourge to the planet.

Harry Eagar said...

Glaringly absent from this palaver is any cultural input. And by that I include economic impacts on cultural mores.

Also religion.

In the Middle Ages when population was precarious and labor was always short, Europeans removed substantial numbers of nubile women from the breeding pool for nutty religious reasons. I mean, we started with Orthodox Jews breedig like rabbits but no mention of the reverse impetus.

I expect that if this Jewish quiverful movement ever became significant (which it may be approaching in Israel) and if it depends on subsidies from working people (as in the Jewish iteration it does; not so much in the Dominionist one), then the larger society will eventually pull the plug on the food packages.

Hey Skipper said...

[harry:] Glaringly absent from this palaver is any cultural input. And by that I include economic impacts on cultural mores.

Well, if it is glaringly absent, then by all means supply it.

Harry Eagar said...

Uh, I just did

Bret said...

Hey Skipper wrote: "...women's desire for children will be satiated, on average, at somewhere between one and two children."

You sure like using the word "average." Average means nothing for future predictions. What's the standard deviation, distribution shape/type, and heritability (both genetic and cultural) of the "satiation" point. To me it's perfectly clear that the standard deviation is large, on the order of 3 children, and the heritability is high. You either think the standard deviation is zero or extremely low and/or the heritability is extremely low.

To think that, you believe that fertility is different than virtually every other human, mammal, and animal trait. I'm not sure why you're motivated to believe that, but okay, whatever.

Bret said...

Hey Skipper:

Let me be clearer. There is no model with non-zero* standard deviation, non-zero heritability (either genetic, cultural, or both), and a non-zero level of attraction to like desires (i.e. a person seeks a spouse who desires approximately the same number of children), that leads to complete population collapse.

Or...

I challenge you to write that model and present it.

*non-zero excludes "essentially zero." In other words, a standard deviation of .0000000000000000001 is essentially zero and doesn't count as non-zero.

Harry Eagar said...

Skipper also seems to be thinking that women get to choose how often they become pregnant. Not true for most women, now or in the past, and will not be in the future if the kind of people Skipper admires control sexuality.

So there's also that . . .

Hey Skipper said...

[Bret:] You sure like using the word "average." Average means nothing for future predictions. What's the standard deviation, distribution shape/type, and heritability (both genetic and cultural) of the "satiation" point. To me it's perfectly clear that the standard deviation is large, on the order of 3 children, and the heritability is high. You either think the standard deviation is zero or extremely low and/or the heritability is extremely low.

I'll take the last point first. Up until just two generations ago, women had no control over their own fertility. (NB, that doesn't mean there was no such thing as birth control; only that women didn't have autonomy in doing so. Now they have complete autonomy.) Which means asserting there is some sort of heritability in the preference for number of children amounts to pure question begging: you are assuming as true that which doesn't need to exist. Demography, over evolutionarily relevant time spans, has never depended upon female preference.

In other words, the complete sundering of sex and fertility is evolutionarily unprecedented. That is one reason I think heritability of completed fertility is zero — it is a characteristic which would never have had any selection benefit whatsoever.

Obviously, there are cultural influences. That is why cultural Mormons (as distinguished from converts) and Orthodox Jews have more children than the surrounding population. But there is no ignoring secularization over time, or that, particularly for Mormons, completed fertility is following the same path as the rest of the US, only from a higher starting point.

One would think that, given the evolutionarily unique environment of ample and predictable resources, coupled with extremely low infant and maternal mortality, women would choose to have a great many children. Unless, of course, in terms of satisfying the maternal instinct, modernity means there are drastically diminishing returns with each additional child.

Which is why I think the word average is perfectly appropriate: absent some sort of genetic preference for completed fertility, for which you have exactly zero evidence, then there is no reason to believe the distribution in completed fertility will be at all correlated with the number of siblings daughters have.

Beyond that, average does indeed matter. (Go to page three.) As of 2012, for women born between 1962 and 1967 (the first generation to grow up with the pill), 35% had either zero or one child, 30% had three or more. Above, I have linked to sources showing later first pregnancies, and continuously lowering fertility rates, which means eventual completed fertility for women now in their prime childbearing years is almost certainly going to be lower than that for women who have just reached the end of childbearing.

Hey Skipper said...

To think that, you believe that fertility is different than virtually every other human, mammal, and animal trait. I'm not sure why you're motivated to believe that, but okay, whatever.



Let me be clearer. There is no model with non-zero* standard deviation, non-zero heritability (either genetic, cultural, or both), and a non-zero level of attraction to like desires (i.e. a person seeks a spouse who desires approximately the same number of children), that leads to complete population collapse.


I'm not at all sure what you mean by a large standard deviation, or why zero deviation is important. The US mean is right around 1.86. By definition, the lower bound of the distribution is zero, the upper bound is probably around six. So a standard deviation will be larger on the right side than left, but so what?

Furthermore, so long as the mean is less than 2, it makes no difference what the deviation is, unless family size preference is genetic, yet there is no reason to believe it is.

To repeat: throughout evolutionarily relevant time, there has never been a disconnect between sex and fertility. Therefore, evolutionarily selecting for a strong sex drive yielded fertility as a consequence. Now the former need not, and mostly doesn't, have anything to do with the latter.

Is there any other trait you can think of that has faced that kind of cause-effect disruption? I can't, which is why I think severing sex from reproduction is evolutionarily unprecedented. Presuming that women's preferred family size is heritable (as opposed to sex drive) is what needs a great deal of explaining.

Especially when all the evidence is on my side. Everywhere women gain reproductive autonomy, birth rates have plummeted. Essentially all modern societies have TLF rates less than replacement, often substantially so. (The US is an exception due to ongoing immigration. First generation immigrants have higher birth rates than subsequent generations.)

So here's my model:

1. Women, on average (i.e., the sum of completed fertility divided by the number of women in a cohort) satiate their desire for children at some number less than 2.

2. There is no genetic component to completed fertility, because that requires creationism.

3. Modernity eventually swamps all cultural influences.

Hey Skipper said...

[Harry:] Glaringly absent from this palaver is any cultural input. And by that I include economic impacts on cultural mores.

Also religion.

[Hey Skipper:] Well, if it is glaringly absent, then by all means supply it.

[Harry:] I just did.


Not if time is at all meaningful.

Presently(and I am repeating myself yet again), while culture and religion obviously affect the starting point for completed fertility, culture and religion seem to have no effect on the trajectory of completed fertility. Which is to say, regardless of those details, eventually completed fertility will eventually converge at a sub-replacement level in all societies that achieve female autonomy and GDP above about $10K per capita.

Skipper also seems to be thinking that women get to choose how often they become pregnant. Not true for most women, now or in the past …

As far as delusional goes, it is impossible to decide which wins, Women who average 6 children have not, until recently, had as many surviving reproducing offspring as women today with 1.2 (or whatever) children. or Skipper also seems to be thinking that women get to choose how often they become pregnant. Not true for most women, now or in the past …

The former is mathematically hilarious, and the latter requires denying undeniable fertility trends everywhere women attain reproductive autonomy.

You really do owe us explanations of both.

Bret said...

Hey Skipper wrote: "...absent some sort of genetic preference for completed fertility, for which you have exactly zero evidence."

I have hundreds of thousands of years of human existence and population growth. You have a handful of decades.

Hey Skipper said...

No you don't.

You have no evidence of women's preferred completed fertility, because until a handful of decades ago, such a thing did not exist.

In the pre-modern era, women had as many children as they got, or as they could survive. Not anymore.

Bret said...

Hey Skipper wrote: "So here's my model"

So of all animal traits that ever existed, exactly one has no genetic component: human fertility (we know other mammals, such as coyotes, indeed have such a component).

Yeah, riiiiiiiiiiiight. Who's the creationist?

You must not have met many women in your life if you believe that there's no genetic component to human fertility. Across the women I know, there's definitely a very large and strong innate difference in desire for children with little or none of that due to religious teachings (I don't know very may religious people). Heck, across the men I know, there's a large difference in desire for children.

At minimum, there is an inverse correlation between intelligence (a genetic and heritable trait) and fertility. So even if fertility isn't directly a genetic trait, it is an indirectly expressed phenotype. As I've written previously, humans may become extremely stupid, but we won't die out to due to lack of procreation.

So your model is simply wrong based on the evidence.


Hey Skipper wrote: "...throughout evolutionarily relevant time, there has never been a disconnect between sex and fertility."

Simply wrong. Women have known for thousands of years that various easily accessible herbs up the vagina prevents pregnancy. Those of the worlds oldest profession have always used them. Females have always had adequate autonomy to access and use such herbs. They've simply chosen not to. For thousands of years. Now, for a handful of decades, some women have been somewhat more likely to use the modern equivalent. And that convinces you? We all believe what we want, I guess.

Bret said...

Hey Skipper wrote: "...there is no ignoring secularization over time..."

Why is that relevant? You think it's not possible for secular women to want large families? I know a completely non-religious women with 5 kids. Again, you're looking at a handful decades in hundreds of thousands of years. If what you think is true, we wouldn't be here having this conversation. Humans would've long been extinct.


Harry wrote: "Skipper also seems to be thinking that women get to choose how often they become pregnant. Not true for most women, now or in the past, and will not be in the future..."

Bingo. If the population drops substantially, women will simply go back to being property and will no longer decide whether or not to have children. In at least some new societal organizations, they will be forced to be fruitful.

Even on the rare chance that desire for children isn't a genetically heritable trait with non-zero standard deviation, in the centuries it would take the population to drop significantly, new societal organizations and memes will evolve, some of which, like the ultra-Orthodox, will have more than replacement birthrates and those groups will inherit the earth. And on the rare chance you're right about secular society never again achieving replacement birthrates, there won't be any other society for them to run off to. It will either be part of the ultra-Orthodox, the only people left on the planet, or run off to the woods and be eaten by wolves.

Furthermore, on the rare chance total human population gets below some point, say ten million, civilization as we know it will be unsupportable, women will go back to being chattel property, and birth rates will climb again, again, in at least some groups.

The problem with your model is that it assumes that a tiny blip in human existence is not only the new normal, but everybody is exactly the same in fertility both genetically and memetically, and will all continue to be exactly the same in fertility no matter what, no matter the changing conditions, no matter the change in civilization, and that no group can possibly evolve to treasure children again.

This is a very, very odd time with society basically hating children and those who produce them. To think that's normal and will continue into the future is also very, very odd.

Bret said...

Hey Skipper wrote: "In the pre-modern era, women had as many children as they got, or as they could survive. Not anymore."

Simply wrong. There's been contraception, for example herbs in the vagina, for thousands of years.

Bret said...

Hey Skipper:

Another thing on the genetic underpinning of fertility.

Do you also believe there is no genetic component in levels of estrogen, testosterone, progesterone, oxytocin, prolactin in women (and men for that matter)? That all women have exactly the same levels of each and everyone of those hormones throughout there lifetimes? Do you believe that every woman's brain reacts exactly the same to those and other hormones and thus that every brain has the identical genetics? Do you not believe that those or any hormones have any effect on baby desire, sexual desire, fertility or any aspect of reproduction?

Well, I guess your answers are obvious given you believe there's zero genetic basis for any possible variance in human fertility. But you're one of the few who believes that.

Hey Skipper said...

You must not have met many women in your life if you believe that there's no genetic component to human fertility.

That is a very odd conclusion to draw. Almost all the women I know strongly desired to have children. Most did. All of them had that desire satiated by the second child. Before the pill, average US completed fertility was something north of four births.

Not anymore, not even close.

So I'm still looking for an explanation of how a gene that has done nothing -- remember, this gene must affect the brain, because the reproductive system will continue working so long as the body does -- since time immemorial, can continue to exist.

So of all animal traits that ever existed, exactly one has no genetic component: human fertility (we know other mammals, such as coyotes, indeed have such a component).

Indeed, we do. And none of them limit fertility, or sex balances, during times of plenty. Extrapolating a system that goes into partial or total shutdown in the face of famine conditions is no help in looking for a gene that tells the system to do what it does anyway otherwise.

Do you also believe there is no genetic component in levels of estrogen, testosterone, progesterone, oxytocin, prolactin in women (and men for that matter)?

I don't think I said, or meant, anything like that. Here is what mean: absence significant deprivation (nowadays available only through excessive training or an eating disorder) leading to amenorrhea, essentially all women who are neither pregnant nor nursing are capable of getting pregnant every month.

Obviously, since everyone has levels of all those things that aren't the same, then they are genetic in the sense that genes built the system, and the system varies among individuals. But for essentially all non-pregnant/non-lactating women, those variations are within normal ranges that result in monthly fertility menarche to menopause.

And what women thought about that fertility was irrelevant.

Simply wrong. There's been contraception, for example herbs in the vagina, for thousands of years.

Do you know the history of the Spanish surname Esposito? Or why foundling hospitals existed?

Neither is down to effective contraception.

Furthermore, on the rare chance total human population gets below some point, say ten million, civilization as we know it will be unsupportable, women will go back to being chattel property, and birth rates will climb again, again, in at least some groups.

The problem with your model is that it assumes that a tiny blip in human existence is not only the new normal ...


Well, if the worst that can be said about my model is that it involves merely the complete collapse of civilization, instead of outright extinction, then I must have some apologizing to do.

Bret said...

Hey Skipper wrote: "... then they are genetic in the sense that genes built the system, and the system varies among individuals..."

That's all my models require and then there's no catastrophic population decline. I'm glad we're in agreement on the critical point: there is a genetic component with heritability to baby desire which will lead to a distribution with non-zero standard deviation.

Hey Skipper wrote: "I must have some apologizing to do."

Yes, you do.

Bret said...

Hey Skipper wrote: "All of them had that desire satiated by the second child."

Really? You don't know a single woman who has 3 or more children? I'm having trouble believing that since more than 1/3 of all mothers have 3 or more children, and even 1/4 of highly educated women have 3 or more children. I'm not sure where you've been hiding out with all of these low birthrate folk. Or are you saying their desire was satiated at 2 but they went on to have more anyway? In which case, I'm not sure what your point is.

I know many, some of them religious, some of them not, many my age and younger, and indeed those I know happen to more or less fit the statistics.

Bret said...

Hey Skipper:

What's even more surprising about your lack of exposure to families with 3 or more children is that Alaska has the 3rd highest fertility rate in the United States (excluding territories).

erp said...

... I think this string is fascinating. Never did I expect that you guys would be arguing over -- of all things -- female fertility.

My life sure would be dull with the GG.

:-)

Clovis e Adri said...

I guess we are back at my point, Bret: while you look to be happy enough granting non-extinction of the human race, I guess most people who think about the topic are more worried about the survival of societies - and the levels of economic and technological activities enabling the world we live in now.

Look at present tendencies: we have rich populations having their offspring self-reduced, with their wealth greatly benefitting the offspring of external (and poorer) populations moving to the depopulating countries.

What's the long term result of that, assuming it gets to be the norm?

Europe looks to fear an islamization that ultimately could hinder their economic growth and cultural relevance.

The Japanese refuse to let foreigners come in any massive wave that could replace their dwindling population.

Russia can hardly become an atractive enough place to revert its depopulation course through immigration.

China may come to welcome its depopulation, if it can keep economic growth at a level they consider reasonable (and robotics will probably allow them so, as it has been with Japan to some extent).

Your model does not touch, nor is relevant, to any of the questions the points above may create.

Hey Skipper said...

[Bret:] Really? You don't know a single woman who has 3 or more children?

I stand corrected. Perhaps on account of being a garden variety guy, I just don't think of other people's families much, not even relatives.

So when I riffled harder through the memory banks, I indeed came up with a few that had three kids. And maybe a friend of my wife's who has four. Unless it's three.

However, those few are swamped by those women of whom I know enough to be aware of how many children they have — not anything like a statistical sample, and please, for the love of God, do not ask for names — they are swamped by those who have two or fewer.

I lived in a well to do neighborhood in a suburb of Anchorage, so no surprise that there were scarcely any families with three or more kids. Most of the state isn't like that, though. According to you, since Alaska has the highest fertility in the US, it must also be the stupidest.

Bret said...

Hey Skipper wrote: "...since Alaska has the highest fertility in the US, it must also be the stupidest."

3rd highest fertility. IQ by state and fertility by state may not correlate very well (inversely or otherwise), but Alaska is the 15th stupidest (36th smartest). Add the rampant alcoholism that tends to go with brutally dark living conditions and it may be effectively even stupider.

Bret said...

Clovis wrote: "I guess most people who think about the topic are more worried about the survival of societies..."

Are they? I mean, we're talkin' hundreds of years. Also, I rather think that all civilizations collapse and western civilization will too. As I wrote here (and I think you'll enjoy this post):

"Every story has an ending as does every civilization. This civilization, like all others before it, will one day collapse, where collapse, in Tainterian terms, is the rapid simplification of society.

So regardless of fertility rates, this civilization's days are numbered (though I have no idea what that number is) and I think it's guaranteed that this society won't survive. But from the hyperfroth the hyperphoenix will arise and a new civilization will be born and human life will continue.

Clovis e Adri said...

Bret,

Yeah, I did enjoy reading that post, full of nice insights.

Yet, I think it is a bit unfair to refer to our numbered days in order to dismiss a lesser worry.

We'll all surely die, yet we try our best to stay alive while we can. Our civilizations may be a blip in spacetime, yet I still get interested enough on its near future inclinations.

Harry Eagar said...

'converge at a sub-replacement level in all societies that achieve female autonomy and GDP above about $10K per capita.'

Tell that to the Mormons.

Although it occurs in a small fraction of families so may hardly distort the demographic graphs,it is pretty obvious that the depressive effects of middleclassness on family size are not permanent; rich people often have lots of children. Donald Trump, for example

Bret said...

Clovis wrote: "...yet we try our best to stay alive while we can..."

Not me, so much. Or rather, yes, I try to personally stay alive but after my death I'm not terribly concerned about the longevity of civilization or homo sapiens.

There will be a last human and how much does it matter to me if that last human dies in one-hundred years or one-hundred million years? Certainly I'd pay $100 to have it be the latter as opposed to the former, but I certainly wouldn't willingly pay $100,000. I'm not sure where the cutoff for me is, but definitely less than $100,000. And I'm not even sure why I'd pay anything at all or make any sacrifice.

What would you pay to extend civilization or the species?

Clovis e Adri said...

Bret,

For the future of civilization? I suppose I could give it a $1 coin if I can find one in my pocket.

For the future of my children? My entire present and future bank account, my blood and my soul.

Of course, it is the strong connection to each next link that makes a good chain.

Peter said...

Worrying too much about the future of civilization can actually be unhealthy.

Hey Skipper said...

[Harry:] Tell that to the Mormons.

I did, above, with links. Mormon fertility trends are following the rest of the US, but from a higher starting point. When I lived in Idaho in the mid-80s, the average Mormon family had 5.5 kids. IIRC, one generation later it is below three. Mormon convert fertility is unchanged by their new faith.

Although it occurs in a small fraction of families so may hardly distort the demographic graphs,it is pretty obvious that the depressive effects of middleclassness on family size are not permanent; rich people often have lots of children. Donald Trump, for example

Wrong.



erp said...

Peter, a good one. Woody Allen, a national treasure, alas gone over to the dark side.

Harry, have you noticed some of our fellow Americans on the dole from so many different directions, programs and initiatives, have waaaaaaaaaaaay over replacement number of children that even Trump couldn't afford them all. Are they counted in your statistics?

Hey Skipper said...

(Blogger ate my original comment last week. Memo to self -- do not biff that text file until I actually see the comment posted.)

[Bret:] That's all my models require and then there's no catastrophic population decline. I'm glad we're in agreement on the critical point: there is a genetic component with heritability to baby desire which will lead to a distribution with non-zero standard deviation.

No, we aren't in agreement.

Clearly humans have the capacity to form preferences -- that much is innate, therefore genetic.

But you are asserting that, in addition to forming preferences, specific preferences themselves are heritable. There is no reason to believe that is true.

Humans must eat -- we experience hunger; since that is a bodily function, of course it is genetic. Humans also have food preferences that vary widely by culture and individually. That should be sufficient to demonstrate that the ability to form a type of preference -- even involving one as important to survival as eating -- does not mean that a specific instance of the preference is at all heritable.

And, as I have mentioned above, throughout evolutionary relevant time, women's preferences for how many children they had were irrelevant. The question you are begging is how it can possibly be that a gene without any survival value at all can continue to exist, when natural fertility, sex drive and maternal instinct are already completely sufficient.





Bret said...

Clovis wrote: "For the future of my children?"

That's why I wrote 100 years as the minimum. My children will also quite likely be dead by that point. If they produce grandchildren, I might move that 100 year horizon out a bit.

Bret said...

Hey Skipper wrote: "...specific preferences themselves are heritable. There is no reason to believe that is true."

One more time. There is no doubt that hormone levels affect procreation desires. There is no doubt that hormone levels are mostly genetic and heritable. Therefore, procreation desires are genetic and heritable.

Hey Skipper said...

There is no doubt that hormone levels affect procreation desires.

At least the third time: Procreation is the effect of which sex is the cause.

Yes, hormone levels affect sexual desire, but there is no evidence the general level sexual desire is heritable. And, in any event, women's desire is highly preference and situation driven; neither of which are heritable. In contrast, female fertility is an autonomous function upon which preferences have no effect.

Having forgotten the cause and effect relationship, you also step over the evolutionarily unprecedented ability of women to completely disconnect sex from procreation. Women can now satisfy their libido, about which evolution has had a great deal to say, without causing procreation, about which evolution also has had a great deal to say.

Which is where Barren and Fertile go off the rails. You are insisting something exists that, until now, has never needed to exist, and, therefore, about which evolution is silent.

Hey Skipper said...

[Clovis:] For the future of civilization? I suppose I could give it a $1 coin if I can find one in my pocket.

For the future of my children? My entire present and future bank account, my blood and my soul.


Why put this part of the discussion in the realm of the hopelessly hypothetical, when there is no need to?

Global Warming. How much are we willing to do now to prevent [insert parade of horribles here] later?

Bret said...

Hey Skipper wrote: "Global Warming"

Indeed. That's why I picked 100 years as one of the time bounds.

And that's part of my argument against doing anything about global warming. Even if right, why should I care enough to make sacrifices? By the time it's adequately severe (if ever) to be bad for the human species, I and my children will be long dead.

Bret said...

Hey Skipper wrote: "Yes, hormone levels affect sexual desire..."

Sure, but that's not what's important.

Hormone levels affect baby desire. See my other post.

Some women desire having a baby MORE than having sex. To that end, sex is just something to be endured to get to the goal.

Hey Skipper said...

Some women desire having a baby MORE than having sex. To that end, sex is just something to be endured to get to the goal.

Given the depth of the desire to have a baby, it is a real stretch to conclude that sex is merely something to be endured. Perhaps you have some assumptions that need checking.

No, wait. What needs checking is logical fallacies, in this case a category mistake. Having a baby is the consequence of sex, but sex and having a baby aren't even remotely the same; they are no more comparable than chalk and cheese.

Especially now, when the are both conceptually and physically distinct.

Also, you keep begging the question.

Asserting that women deeply desire a baby says nothing about how many babies they want. Clearly, where women have the agency to decide for themselves, it is a heck of a lot fewer than they are capable of bearing.

What part of evolutionary theory says decisions are heritable?

Bret said...

Hey Skipper asks: "What part of evolutionary theory says decisions are heritable? "

Baby fever (desire) is traced to hormone levels. Hormone levels are heritable. Unless you're gonna claim decisions aren't linked to desires (which would be utterly absurd), then decisions to have babies are heritable. There's clearly a big variance and that's all that's needed.

Clovis e Adri said...

Skipper,

---
Global Warming. How much are we willing to do now to prevent [insert parade of horribles here] later?
---
Remember de Ozone hole?

When cause, effect and solutions are clearly identifiable, I guess we are willing to do a lot.

Which is part of the problem with the Global Warming sci-policy crowd. They desperately wanted to secure consensus, in order to move to the next phase, action, without barely understanding what that action should be.

To some purposes, it worked. I know people doing good careers on the subject. Their children will surely be better for it.