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Comment by gumby | Hacker News Reader

I have mixed feelings about this: Julian Simon did a pretty good job of supporting the anti-malthusian thesis, and that more people implies more opportunities for creativity.

On the other hand he didn't disprove such a theory either -- we might have been just moving up a curve towards a critical point, where hysteresis then screws us.

But in general I'm pretty neutral: if people want more kids, great; if they don't, that's great too. So this sentence right at the front of the article really disturbs me:

> Population growth is vital for the world economy.

Most people seem to agree with this statement, which is the very definition of a pyramid scheme (see my point about hysteresis above). We've defined the goalposts such that this statement is in some sense tautologically true, but it leaves me with a profound sense of "so what?"

If fewer people are born, ultimately fewer houses will be needed, but why should that presume that less house construction will happen (perhaps there will be lots of renovations, or removal and new construction, or house builders will simply move to new fields as horsecart makers did).

We already know our growth metrics are crude and wrong, though we don't know really how much and in what ways. But there are plenty of potential scenarios where economic growth and human wellbeing does not require massive, or perhaps any population increase.

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So if the population grows from 1 (in units of 8 billion, say) to (1 + A), and the productivity per person goes from 1 to (1 + B), then the world economy goes from 1 to (1 + A) * (1 + B). If the population doesn't grow, then the economy only grows to (1 + B).

As you say, so what? Is the world economy some kind of deity, that we are here to serve its needs rather than our own? If each of us are the same (1 + B) better off, why do we care whether the global economy grew more or less?

As Edward Abbey said, "Growth for the sake of growth is the ideology of the cancer cell." If the growth actually leaves people better off, that's a positive. But if it just makes bigger numbers on a page, what's the point?

It's a problem for rich people and governments, who get to take a fraction of everyone's productivity through surplus labor value (i.e. capital gains) and taxes.

Rich people are the only ones who will get to reproduce.

It seems to me obvious that if I have a computer, I am more productive than with a stone axe, and it is a more productive asset if I am using it.

There is obviously a surplus from combining labor with capital, and an inevitable struggle over allocating it, but I don't understand at all why people ostensibly think it's obviously all rightfully belonging to one or the other.

If I earn a dollar, and then I collect interest on it, then the interest is really a part of my wages that was withheld. It's not extra. Whether anyone is being cheated of the amount of the interest depends on whether I got the dollar honestly, or cheated or stole to get it, but that has nothing to do with the essential nature of labor or capital.

It isn't just a problem for rich people, it is a problem for everyone who can save money. A growing population means that everything can grow accordingly (businesses, infrastructure, …) so there are good investment opportunities. If you can afford to save money, this means that there are productive things to do with that money, and you'll naturally get higher interest rates (and increasing stock prices, etc.). Higher interest rates aren't all good, but extremely low interest rates (like in Japan for the last ~25 years) aren't good either, especially if you want to save for retirement. Social Security isn't the only useful "pyramid scheme."

The analogy with the cancer cell is spot on, it sure feels we're still very much like one, having to spread and expand in our ever struggle against nature.

Imagine if we manage to find a way to create small long term ecosystems... then the cancer will spread to the stars and these birther catastrophists will be relieved: we'll go back to 10 birth a woman with 2 babies making it to 40 :D

Exactly. This push for economic growth is a recent invention historically. Let’s go back to not fucking over each other or the planet for money. We should aim for 2 billion world population in the next few centuries.

So go back to what pops were in 1930? If people would level off their mass consumerism and appetite to one up each other we could probably all live well at 1960s levels. But to get back down there it has to be carefully managed to avoid imbalances and collapses. Unfortunately history has some bad lessons for us to learn from; China, the early XX century’s idea of creating new super people and eliminating those of us who are weak or could have undesirable characteristics, and obviously worse. But, we do see education, especially for women along with jobs for them in the regular economy do lead to a quick decrease in TFR.

Recent? Genesis 9:7

The verse says nothing about economic growth.

Growth as a primary focus of economics dates only to the 1950s.

I believe it was Paul Romer who was asked at the time to survey the extant literature on growth. His report: there was none.

If you want to quote the bible, then quote the bible. Not everyone can be bothered to look it up.

Amen

10 million max

I don't care about the world economy per se, but I do care about people.

One aspect seldom considered is the value of life itself.

> If each of us

Therein lies the consideration. Who is important? Who is "us"?

Are the people living important? Are the people not living important?

I.e. would it be a "bad thing" if you did not exist? I presume you think so. Should we think so?

Would it be a bad thing for another person to not exist? What about a future person?

---

The value, source, and identity of human life gets very religious/philosophical.

My beliefs include human life having intrinsic value, and I therefore would like there to be as many human lives as possible and for those lives to be good as possible.

You'll notice that my conclusion winds up equivalent to the economics notion of "collective utility" (1 + A) * (1 + B). That is true, but I prefer to think of it not as adding more pennies to a global piggy bank, but in a real altruistic sense of maximizing human experience.

Your simple system is broken when a happiness sink (let's call him Bob) is introduced. Bob is extremely happy, but everyone else toils and is moderately miserable to make him happy.

Welcome to current society. Bob is the richest few.

>> Population growth is vital for the world economy.

> which is the very definition of a pyramid scheme

AFAIU, population growth being beneficial is predicated on the notion that not only does every additional human contribute a pro rata factor of N=(contribution/cost) wealth to society, where N is greater than 1, but more importantly that for every additional human N increases.

Maybe some professional economists can cite to the particular theories and research (I'm too distant from my academic days), or alternatively disabuse me of this notion. But that's my understanding, and in that light population growth is definitely not a pyramid scheme.

It doesn't mean that population growth is the only way to increase N. There may be ways to increase N fast enough to compensate for the loss of the population growth dynamic, but those ways seem to be fairly elusive.[1] It also doesn't mean that there aren't pyramid scheme-like dynamics elsewhere (e.g. land use, housing prices, etc); they're just not intrinsic to the overarching dynamic.

[1] And that's because rate of innovation is partly a function of population size. The more people there are, the more risk takers exist, the more opportunities available, the more possible social arrangements, etc.

An analogy: To a first approximation, the more neurons you have (population), and the more interconnected they are ("free market"), the more capable and potentially intelligent the network.

That is a good statement of Simon's thesis, but as I discussed in my brief note there is nuance he did not address in writing (he was super smart and told me once that he understood the issue but didn't know how to characterize it).

> An analogy: To a first approximation, the more neurons you have (population), and the more interconnected they are ("free market"), the more capable and potentially intelligent the network.

A good analogy but every system has a "sweet spot" regime; outside that zone various advantages stop being (evolutionary, in this case) advantageous, else our brains would be eve larger.

When I was working on onion routing and mesh networking 10+ years ago, I remember reading a paper that showed that in a mesh network every additional node added total throughput capacity, but the rate of increase asymptotically approached 0.

I don't have the citation handy, and I'm sure the proof was tied to a particular topology, but the take home for me was that it was possible for mesh network advocates and skeptics to both be correct; that mesh networks can be a way to continually increase network capacity cooperatively without centralized authority, but that doesn't mean such capacity increases would be meaningful.

The same might apply here: yes, the rate of increase in N may approach 0 such that at some point it becomes an irrelevant factor to economic growth. OTOH, in the absence of alternative drivers even a tiny rate of increase is something, and removing it could lead to accelerating reductions in global wealth.

But we just don't know. The relevant questions and answers are more empirical than theoretical. My point was just that the growth narrative isn't predicated on a pyramid scheme, it's just the safest and possibly only known reliable strategy we understand. But an end to population growth seems inevitable in the next couple of generations (barring space colonization), so I suppose we'll find some answers rather soon.

I think AI would change this. We will eventually have ‘artificial persons’. I can guarantee that once global population starts to taper off, the decline in population would make us a less interesting and dynamic species.

Complex systems need a large number of people. We will have to create some version of the missing billions. Perhaps robots or AI personalities or mash ups.

As a casual example..a personal story: I recently had this revelation when I met someone from a small western country with a population of about 5 million. This person was incredibly smart, highly accomplished, well travelled and older than me.

But I still found that he was somewhat oblivious to what I call ‘nuances of human nature’. I have never considered myself a particularly perceptive person or highly tuned into human personality, but because of the accident of birth in a country that has over 1.3 billion people now, I was exposed to a wide circle of different people..and even though this other person was far ahead of me in every way, his exposure was limited to a smaller cocktail of human natures.

Did it make me smarter? I don’t know. But I sure was exposed to so much variety that I could at least detect differences and variabilities..even minute ones. I think my view of life is richer, more colorful and interesting.

To bring up another example: a larger population is like being a native speaker of Cantonese with its eight tones vs being someone who can speak a language with exactly 100 words. Entirely different worlds and one is vastly richer than the other.

So to combat this, we just have to create artificial people and virtual world when we finally achieve the carrying capacity of about one billion people(the population of the planet in 1600)

You don't seem to be considering that each one of those additional people is a mouth to feed, agricultural land to farm, a house, car and iPhones for them, some number of tonnes of carbon and other lifetime emissions.

The planet and its resources has a finite carrying capacity. Given we have most of the world in need of developing to reach the levels we enjoy, I suspect we are far past that capacity already -- though I am unlikely to live to see the consequences of that. We've used the world's most fertile land already. We've had the fossil fuel fertiliser dividend. Do we continue to grow and pretend growth is normal and necessary until we absolutely need another agriculture miracle? Or do we try and construct a future where everyone has a chance of abundance?

Even claiming innovation is partly a function of population size is far too simplistic - we've had periods where small countries were punching orders of magnitude above their population weight. There'll be little innovation if the food supply breaks.

> The planet and its resources has a finite carrying capacity. Given we have most of the world in need of developing to reach the levels we enjoy, I suspect we are far past that capacity already

This argument has been made for hundreds of years, and for hundreds of years it's failed to pan out. Perhaps this time is different though.

"The power of population is indefinitely greater than the power in the earth to produce subsistence for man." - Thomas Malthus (1798)

Malthus was a while ago - what leads you to believe the planet now has an infinite capacity for humans?

I should clarify I was responding to your assertion that the earth is far past capacity.

~10% of Earth’s land is occupied by humans. Not all of that is arable, but humans have successfully terraformed throughout history and conceivably will become more capable with technological advances.

Malthus is not unique in his prognostications. Ehrlich’s The Population Bomb (1968) was more recent and predicted mass famine by the 1970s. Instead, we produce a massive surplus of food each year, although it’s not distributed adequately at present. This happened well after the Haber process (presumably the fossil fuel dividend you refer to) and occurred as a result of improved farming techniques, equipment, and crops.

Thanks to technological developments in the fossil fuels sector (fracking, horizontal drilling, etc.), fears about running out of oil have largely subsided. Simultaneously, advances in renewable energy sources are rapidly reducing our reliance on fossil fuels. Already, some electric grids are struggling with capacity — not because of a shortage of energy, rather due to an excess of electricity produced by renewable sources.

Although none of this points to an Earth beyond its carrying capacity, it also does not factor in further efficiency gains resulting from future technological progress. At the same time, we are attempting to develop the technology necessary to access extraterrestrial resources. Given that, even the finite resources available on Earth are not necessarily a limiting factor to growth.

Call it half of land area, not 10%.

Of total land area circa 10% is developed, 10% arable and a shade over 25% permanent pasture for livestock[1], and a few other minor agricultural uses. Of the rest we have forests, permafrost, deserts, mountains, marsh, scrub and other marginal land. The best crop and pasture land is long gone. What's left with potential appear to be the places we need to not lose - rainforests and such. God help everyone if we are able or need to start farming former permafrost.

Changing farming through mechanisation, artificial fertiliser and de-population of agriculture has been a steady march since WW2 (mostly). All leveraged on fossil fuel, and mostly a one-time dividend.

Past capacity as the rest close the development gap (you can't just miss that out), based on all resource use, and associated pollution - environmental overshoot - not mere calories. Not just a baseless assertion as we are assessed to be 70% beyond the ecosystem's capacity to absorb[2] right now. We've been beyond it for years. We're on borrowed time even without more development. Overshoot day[3] has gained a fair bit of publicity in recent years, but there's plenty of different measures all pointing to the same trends and issues.

With that level of accelerating overshoot, the planet can barely cope - the list of global scale and population related issues is huge. Yet coming en masse as a "surprise" is mostly to be expected given the growth curve. So there seems precious little headroom left, even if we do miraculously work to achieve zero carbon by 2050. Not expecting us to get anywhere near it any more though. Pretending population is just fine, or "growth is vital" as TFA claims is, whilst the globe does almost naff all to become sustainable is, frankly, nuts.

[1] https://en.wikipedia.org/wiki/Agricultural_land

[2] https://en.wikipedia.org/wiki/Carrying_capacity#Ecological_f...

[3] https://en.wikipedia.org/wiki/Earth_Overshoot_Day

Thank you. A lot of what you have said resonates and you have made your points eloquently and patiently.

> The planet and its resources has a finite carrying capacity.

And we are nowhere near reaching it. Increase in economic output with population increase is what matters.

If you have people who can't earn a living and die from hunger, it's bad. If you have people who can cook porridge out of an axe, that's good.

Loonie idle intellectuals from places like Club of Rome are first to point "let's sterilise Asians," like as if they don't see that Western material consumption was bigger than that of all "dreaded Chindonesia" combined.

Remember, those loonie first dreamed of those Malthusian horrors long before even agriculture in the West was doing well, and their prime imperative was to plainly get more resources for themselves.

I do not doubt that when we will hit the feared "Malthusian runaway" at 40B-50B people, planet's economic output would be so great that people would have hard time imagining how nutrient scarcity ever been a thing, and we will be able to "simply throw more petawatt-hours" at the problem.

> And we are nowhere near reaching it

Evidence for that? There's a fair selection of serious planetary scale human impacts right now - food chains, species loss, plastics, and I haven't even mentioned climate yet. I haven't heard of any of the Club of Rome calling for sterilisation of Asians either - neither have the search engines. So that seems baseless hyperbole.

There's a substantial difference between the carrying capacity of the planet and specific problems related to resource mismanagement.

The idea climate change wouldn't be an issue with "less people" is absurd. "less people" don't suddenly create viable electric cars and fusion power.

Why is that absurd? Unless you believe for some reason that there's no safe level of CO2 emissions?

There literally isn't. Fossil fuels are CO2 which was removed millions of years ago, and took millions of years to sequester.

Any rate of active fossil fuel burning above the tiniest of baselines is going to be a net CO2 contributor.

But perhaps more importantly: why would fewer people, with the same amount of resources to share, not simply use more of them? Most efficiency improvements have been driven by rising prices due to rising demand, not awareness of climate change.

EDIT: Worth noting, this is also materially different to the extraction of fossil fuels for other purposes - like plastic.

I didn't say that. Yet fewer people would undoubtedly emit less and need fewer resources. At some point - I have no idea where - there is a number who could have gone on living a fossil fuelled lifestyle indefinitely without it impacting on global climate. Increasing population is tied with increasing emissions. Fewer people would unarguably have lower impact. Fewer people wouldn't magically fix overnight what we've already wrought - that's silly.

Humans have always mismanaged resources. More humans means more mismanaged resources. Not all of the planet's issues are resource management though - a selection are simply down to sheer space used - forest clearcut, development such as roads and cities built and land farmed, etc.

What makes you think the humans of this planet can manage resources substantially better?

It is very weird that your solution to political problems is to brute force them by adding more people of which most will simply defend the status quo.

Electric cars are 19th century invention. It is just a matter of deciding to no longer subsidize damage caused by CO2 emissions.

Fusion is also known to be limited by the lack of funding. I've read stories about 13 year old teenagers building their own fusion reactors. The bigger challenge was getting the financial support from parents.

Climate change mitigation has never been about feasibility, it has always been about finding a solution that is immune to politics.

>Fusion is also known to be limited by the lack of funding. I've read stories about 13 year old teenagers building their own fusion reactors.

Wrong. Fusion reactors you can build at home are just novelties, and don't produce more power than they consume. No one has yet figured out how to actually do that, and until you can do that, fusion isn't useful as a power source. The only place we've ever seen fusion produce usable power is in a star. There's lots of research into building complex reactors to try to replicate this without needing something the size of a star, but no one's actually done it yet. It might be doable with enough funding, or it may never actually work; there's no way to say for sure.

The real problem is that too many people on this planet consume too many resources, and Americans are the worst. If most people lived in cities as dense as Tokyo and got around on trains and bicycles instead of cars, we wouldn't be having most of these problems. The amount of energy consumed per capita in America is simply unsustainable, and too many other people want to emulate this, but there's simply no way for that to possibly work on this planet: there isn't enough land or enough energy.

There's an amount of energy being shot at the planet by the sun every day. Human civilisation uses a lot less than a percent of that.

Solar energy isn't currently usable for personal vehicles, and it's going to be a little while still before that changes. Even if we could magically make cars and trucks all battery-EVs tomorrow, most of our power is still generated from fossil fuels, not solar power, and that's not likely to change soon, though it is of course slowly getting better. The more fossil fuels we burn, the more CO2 we put in the atmosphere, and accelerate climate change.

Sure, if we could overnight make all cars and trucks into battery EVs, replace all fossil fuel power plants with solar PV arrays (and wind farms too, since those are basically driven by solar energy too, though indirectly), and come up with some kind of storage technology to handle nighttime, high latitudes, clouds, still air, etc., then the energy aspect wouldn't be such a big deal. (Even better if we can make battery-EV airplanes.) But we're not there yet, and it's not likely we'll be there for quite a while unfortunately.

And even if we did accomplish that, that still doesn't solve the space problem. There just isn't enough room for everyone to have a big suburban house in a nice place with mild weather, and drive a personal vehicle everywhere. But if we tore down our car-based cities and rebuilt some just like Tokyo with that kind of density (and honestly, it really isn't as dense even as Manhattan; there's a lot more tall skyscrapers in NYC), then we actually could, while simultaneously having far, far fewer car-related deaths, and also having a much healthier population.

>And we are nowhere near reaching it.

Earth overshoot day is already in August [0] which basically means we are consuming it 1.75 times more bio resources than the carrying capacity of the Earth.

[0] https://www.overshootday.org/newsroom/past-earth-overshoot-d...

>The planet and its resources has a finite carrying capacity.

It's a hard jump, but there's not just the one.

We could all be dead, or society be reduced to medieval levels where the technology to leave our gravity well no longer exists.

Not even sure if that's about space or about heaven. Same baseless belief in salvation to me.

Yes, granted, but there's not an unlimited number of planets out there either.

Have you heard the puzzle about the bacteria colony that doubles its area in the agar tray every night? On day 10, it occupies half the area. How long before it occupies the whole tray? One more day. You can add another agar tray or ten or a thousand, but it doesn't buy you that much time.

At a constant growth rate, if the solution eventually involves spreading to multiple planets, it's just a few more centuries before we're running low on planets, almost regardless of the size of the galaxy.

It’s unlimited on any practical timescale an individual should reasonably care about.

We aren't going to be shipping billions of people off to Mars. We'll send some small number and they'll reproduce over there. Having a backup will be great, but it does nothing to address the population that's already here.

> Population growth is vital for the world economy.

The thing is we know world population boomed for the last few centuries. We don't know what will happen if that stops, there's simply no observations yet. Hysteresis is indeed the major question mark. We can certainly imagine some terrible problems.

Probably the biggest problem that comes out of this imagining is a reverse specialization effect. Think of the economy as a tapestry of different specializations, some of which support a very few people on a global scale. For instance, any particular thing that people get phds in like particular materials research. Or industries that are highly concentrated, which you'll find quite a lot of if you look closely. They might stop being viable on their own, requiring consolidation into wider industries or they'll get dropped entirely.

The hysteresis comes in where we go back to a previous population but we unfortunately cannot support the same economy. You see things like that article about the Japanese trainline that stopped once that girl finished school. I mean that town might well have had a train when it was a similarly sized town getting bigger, I don't know. But that kind of thing might happen in many places.

Have to agree - it was the first thing that struck me as worrying as well. We need to be able manage our economies without subscribing to the fallicy of unlimited and unrestrained growth. The planet can not support an infinite number of people.

No, but if tomorrow is better then today, then in some capacity more resources were successfully allocated to it. You can have growth with zero additional material use.

> Most people seem to agree with this statement, which is the very definition of a pyramid scheme (see my point about hysteresis above). We've defined the goalposts such that this statement is in some sense tautologically true, but it leaves me with a profound sense of "so what?"

For countries with any kind of social / welfare programs, there is no option available but to grow population. Even here in the USA programs like social security are only solvent to 2037[1]. Many state programs (such as public pensions) are in way worse positions...

1. https://www.ssa.gov/policy/docs/ssb/v70n3/v70n3p111.html

Why? Productivity continues to increase, regardless of population increasing. It's like saying we can do more with less everywhere, except when it comes to taking care of people and the elderly.

Taking care of the elderly is a labour intensive business. Automation doesn't clean an old person's glasses (real life example), make their bed or cook their meals.

Not yet.

Automation doesn't need to do any of those things (even though it eventually could). It could simply make other industries so cheap and efficient that more labor flows into elder care.

increased demand will drive more automation in that sector

self driving cars may be limited but they will be a great solution for the elderly

The labor intensiveness is not binary.

Specifically, if there are socialized "assisted living" facilities, or even in-the-community caregiver visitation, then the amount of caregiving work-hours per day per elderly person is X. If the only possible arrangement is getting a live-in personal care-giver, then that figures is 2X or 3X (or some factor, I don't have the figures); and most people probably just don't get care.

Ultrasonic cleaners, man!

I don't think that actually holds. I hate to trot out the typical example, but Norway seems to be doing pretty well on the social welfare side with a fertility rate much lower than that of the US. They just have very different priorities than the US does in terms of taxation, wealth distribution, and of course deficit spending vs. creating a sovereign wealth fund.

I don't see any reason why the US couldn't maintain social welfare programs in a decreasing population scenario provided the decrease is gradual, productivity rises as fast as the population goes down, and we actually taxed people appropriately and got our expenditure priorities under control.

Norway is also very homogeneous. We are more willing to be generous to those related to us; and I'm not talking just about race, but also culture, values, and ideology. In all these respects, the United States is far more diverse.

So I guess I agree with you, but I don't think those conditions can be replicated here.

I don’t know why you were downvoted. You are right. I have found this to be true in Japan too.

Homogenous populace = low conflict.

Norway’s top personal tax rate is similar to the US (39%, which is less than what some people pay in high cost of living states here).

The difference, as I’m sure you already know, is state oil revenue, and that can’t last forever even with sovereign wealth funds.

Why not? You could have a welfare system that redistributes any excess return from the fund above long-run inflation rate, and it would be sustainable.

A significant fraction of the historical rate of return on capital is attributable to the combination of population growth and inflation. Without those the size of the fund you would need to cover a material fraction of government spending would be implausibly large.

Sovereign wealth funds also aren't all that different economically from taxation, in the sense that the profits from what the fund is invested in go to funding government programs rather than being reinvested in private enterprise. If the fund was large enough to be relevant, that would become an issue for the economy.

Sweden, Finland and Denmark are also very apt examples, none of whom have oil.

(Norway also uses very little of its oil revenue, saving most of it)

>with any kind

No. That's obviously the case for countries whose welfare system has been designed as a pyramid system.

But saying that any kind of welfare is necessarily unsustainable is as absurd as saying that spending on video games or Ethernet cables is necessarily unsustainable.

As with many things the optimum is not at the edges. Too much or too little fertility are bad, though they lead to different problem sets.

In the short term I think slightly below replacement level is ideal. Once we get past fossil fuel dependence at or slightly above replacement might be best. As long as we run on fossil fuel we are basically putting our children on a credit card with an unknown interest rate.

We already know how to get off of fossil fuels. We know how to make solar panels, nuclear reactors, electric cars, electric heat pumps, etc. The technology exists. It will likely continue to improve, but we could do it entirely with what already exists.

If we deploy it by the time today's unborn children become a significant fraction of the global carbon footprint, it isn't going to matter how many of them there are. And if we don't deploy it by the time today's unborn children become a significant fraction of the global carbon footprint, it isn't going to matter how many of them there are.

There are various types of network effects that happen as a result of larger populations. Greater use of specialization and comparative advantage. Economies of scale. Agglomeration. All of these tendencies allow for niche fields like quantum physics to be viable.

A very tiny fraction of the population is capable of understanding it, and to keep it a thriving discipline, we need people actively studying it. Statistically speaking, if only one in a million people is capable of understanding it, then you're in trouble if you don't have that many millions, and if the people with the capabilities are required in other equally important fields.

Transmitting this information purely through written works is extremely difficult if there are no living mentors. And the resources necessary for something like CERN are vast, and only possible to fund in an enormous economy.

Same story with semiconductors, rockets, MRI machines, and most other important technologies.

> All of these tendencies allow for niche fields like quantum physics to be viable.

Well, Quantum Physics was created by a population that was approximately 1/6 of ours.

Becoming hyper specialized appears to eventually create productivity issues. Scientists have sometimes made progress just by applying ideas from one specialized part of physics to another, where they were unaware of the progress in related ideas.

And there are more mundane costs. The more specialized you are, the higher the odds your tiny niche will go away due to market or technological changes. That means losing income retraining and finding new work.

well what if we managed to keep a stable population of a few billion? we've already demonstrated that it's a sufficient number for all the processes you named

It makes sense for the current dominant population (adults with power) to perpetuate this because a) their interests are tied to economic growth. And b) when they get old they want a good economy and many people to look after them, fund their pension, and (literally) wipe their arse in a nursing home.

Beliefs get perpetuated because they serve a purpose not because they’re actually true.

Excellent points. For many reasons, economists are going to have to give up their fixation on 2nd-derivative metrics sometime this century.

Read "prosperity without growth" https://en.m.wikipedia.org/wiki/Prosperity_Without_Growth

This neglects the massive rise of infertility in the last few decades (eg, sperm counts are halved). It doesn’t seem to be a choice for a growing number of people (I guess if you’re well off there are some procedures that can help)

What's interesting about that is the fact that it seems to be only men affected by rising infertility [1].

[1] https://www.livescience.com/38877-infertility-rates-drop-uni...

Can we actually get numbers for men, or is that just too hard?

Supposedly that's wrong. An economist I think named Solow showed the US economic growth in the early to mid 1900s was almost entirely due to innovation, not labor. The population growth equals wealth is more due to the Marxist concept that labor is wealth.

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