A lot of the 19th and 20th century thinking on population growth was completely up-ended by several major advances: first the Haber-Bosch process of fixing atmospheric nitrogen into ammonia/fertilizer (and now "Nearly 50% of the nitrogen found in human tissues originated from the Haber–Bosch process"), then the discovery of antibiotics (which basically enables modern surgery), modern sanitization, and so on. And since then we've been changing things so fast that I don't think it's easy to predict what things will look like 3 generations from now. What happens if we figure out fusion in 100 years, and fusion power does to several other industries what Haber-Bosch did for agriculture? What if we figure out some major part of human cell senescence and people live to 200-300?

Interesting times coming, to be sure. But I'm a bit more optimistic. We figure things out, eventually.

> When populations are half what they are now, housing will likely be cheaper

I thought like this, but pondering a bit, climate change and associated sea level rise will probably destroy many coastal properties where a lot of people live today, so I suspect this alone will delay housing affordability return for at least one generation. See https://www.aljazeera.com/news/2024/9/28/coastal-communities...

Abandoned houses with no youthful labor to repair will have little value as a place to live. It’s not like available housing in Montana will change prices near NYC.

> When populations are half what they are now

The people in charge in the west are not going to let this happen. Look at Canada.

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Pollution has more to do with high intensity resource usage and unpriced negative externality than the # of people who are alive. For example, meat is much more energy intense because you require farmland to not only feed people, but also the cows. It also pollutes more, in addition to being more expensive to buy, but not expensive enough to cover all the damage being done to the environment.

Also, increased efficiency is a form of economic growth. We are after all doing more with less.

Another important thing to consider is that population size allows and enable certain economic activities to exist. For example, I go to theater and do theater activities, but theater can only exist if enough people go to theater. That threshold can be more easily reached if your theater is in a city.

If you want computer to exists, you need a certain amount of specialists dedicated to that. You need a large population because not everyone cares about computing and there are essential tasks that first need to be taken of such as agriculture and grocery stores and trains.

Finally, economic growth is desirable the same reason improving technology is desirable. It enables more capabilities. The bad side is when we abuse these capabilities, not that these capabilities are bad in itself.

It’s not about higher population. It’s about not having a lopsided demographics. Spend some time in front of a whiteboard, imaginary or actual:

- Less working age people

- More old people

- More geriatric people

This is the transition which you skip over before you get to the fewer but better-off people. (Better-off? Well I have retiring at 72 years of age or later to look forward to, compared to something like 65 for my father.)

Larger populations both enable and incentivize more R&D, art, etc resulting in net positives in the short and long term. That’s somewhat counterbalanced by smaller global population having more resources per person to work with, but you have fewer geniuses with 0.8B people vs 8B people.

The speed of population collapse also impacts our ability to care for infrastructure and the elderly. While I personally think the global population would be better off at a steady 2-5 Billion people vs 10-20 Billion, dropping down to say 100M would make modern electrons manufacturing difficult to maintain let alone improve upon.

Cheaper goods, larger market, more things to market, age demographic balance, broader cultural influence (inasmuch as one believes this to be a good thing), increased chances for innovation.

All or some of this probably ties into what people mean by "economy", but I think it doesn't lend to any appreciation of the material difference that having more people thrown at a problem presents.

Taken to the extreme: a world void of other humans might be entertaining but would be a woefully inefficient place to learn about medicine or the cosmos. Which again presumes an audience who cares about any of that, but I wager that many do. Automation certainly replaces some people for some tasks, but we haven't escaped the need for humans yet.

The case for higher population is that population growth brings economic growth, which brings prosperity.

> Let's fix the growth-based economies and move on with fewer but better-off people.

Fewer people is easy, but fewer-but-better-off people seems very difficult. The wealth- and tax-revenue-creating capacity of the stock market (which has been going up at an inflation-adjusted average of ~6% annually since the late 1800s, driven by growth) simply cannot be replaced. With compounding 5% returns, saving 10K/year will net you a ~$700K nest egg over 30 years. With a flat market, you'd only have $300K.

Nature vs Nurture I guess. If more people = more progress we would see way more innovation coming from China/India/Africa.

Each of those places has double the population of Europe and 5X that of the USA, but aren't really driving human progress in any meaningful way. It seems like pouring more resources into fewer people has better outcomes. 2-3 generations of depopulation might be what we need to make space for some huge innovations.

The case for higher population is that it indicates that a species is thriving.

Higher population spreads out the cost of technology making it affordable. Right now 5 workers support every retiring boomer, this will drop to less than 2 in our old age.

Spending time in the wild may be more unlikely as the time required to maintain a lifestyle grows beyond the number of hours in a day.

Having your dna lottery tickets in the urn that is global conflict?

> What's the case for higher population?

I don't think you understand the math of this. It's not that anyone wants a higher population, it's that the spectrum is a little screwed up. There's this line in the middle (fertility rate 2.1), and anything to the right of that is "population spirals out of control". Then everything to the left of it is "human extinction in just a few centuries".

We're currently on the "human extinction in a few centuries". And all the arguments that we're not are positively stupid. People seem to think that we're like moose on some island, that "population bounces back" (it does for animals, because their fertility rate never goes below replacement, so when population pressures subside, their populations recover). Every time you ask "what's the case for higher population", you're actually helping to murder our entire species.

If you were rational, you'd be pushing the idea that we need that 2.1 fertility rate, the one that doesn't result in higher population, and doesn't result in human extinction.

> What's the case for higher population

maybe you missed it when you first read the article, but it is explained, at length, in the article

>What's the case for higher population?

A lot of society is a ponzi scheme e.g. social security, insurance. Young supporting the old. In some senses, young inexperienced people "paying their dues" are handling most of the frontline gruntwork. No young people means scutwork for the rest of us by definition. The final revenge of the young naive. That's the "real world" case for it.

The nationalistic case for it is harnessing a natural resource: population. Big country in terms of population can dominate others economically and militarily. People is power and leaders want power.

The humanistic case for it is that of Eli Musk : humans keep growing exponentially, as does knowledge, as does economy, until blossoming out into space and the universe. The futurist view. Idea being, the more people there are the faster that happens, the lower the risk.

> Let's fix the growth-based economies and move on with fewer but better-off people.

Yes, they will naturally fix themselves. it will be painful for some as goods become more expensive, but life gets easier - less traffic, cheap housing, fruitful resources, and so on. Japan has it figured out. All the beautiful rural places to live. Places like that fully exist in the US now too (see: appalachia)

But here's what happens on the long term that is obvious to me : population will begin growing again. They'll be some gene variant that makes people deeply want to reproduce on a biological level. In a few generations everyone will have this gene (people without it... they didn't reproduce). Call it a genetic bottleneck on the genetic will to procreate.

It's worth noting that in 5-10 years we could easily have cloning vats. We now have "cloning as a service" for all pets and livestock, many such commercial companies - on a biological level it's trivial to imagine the same service and structure for human, the only barrier is ethics and regulations. We have cloned primates and cracked the underlying tricks that might equally clone a human. We have cracked genetic modification vis a vis an infinite number of genetic mouse models and CRISPR. We have early stages of artificial wombs (CHOP; some years ago) but equally one could make a human chimeric pig to incubate the clones. I don't envision this will be seen in the near future but at somepoint, somewhere along the lines, some nation state will begin doing this in secret not unlike a manhattan project, and as we saw with nuclear proliferation, once the cat's out of the bag everyone will do it, everyone will complete the civilizaton "world wonder" called "The Cloning Vats" https://alphacentauri.fandom.com/wiki/The_Cloning_Vats

You may be overestimating the subjective importance of elderly care/life span maximization. I think many would be just as fine with assisted suicide in that setting. I, for one, would rather not end up as a demented mummy which I've seen plenty enough of.

Sure there's pre-terminal scenarios where adult children may be of help, but different living arrangements could mitigate that.

IIRC I've read that even pre-modern cities have often suffered from below replacement fertility, propped up by countryside migration. Children are decent laborers for subsistence farmers.

But yeah, as others have pointed out, it may well be a socially contagious mood that's causing the current trend. Personally, I'd like to think it's having to do with our imposing technosphere causing wildlife extinction, global warming, etc and a desire for better balance, but that may be too optimistic.

Probably because there's a lot of smart people here. Demographics is the one trend that overpowers any other. Technologies, Productivity, GDP, Debt, Religion, Culture, all pale in comparison. Paying attention to that is important. Although I understand your sentiment, in the end we're all dead.

The lords of tech are obsessed with it because they exploit the macro economy so it makes sense the accolytes here would follow suit