Well, this is all assuming that humanity will not expand out of Earth. If that does happen, we might actually have a perpetually expanding populace and economy. Fun times.
I think you're assuming the current decline in birth rates is due to scarcity of resources. But I don't think that's true. In the developed world food and energy are not scarce, and even land outside of major metro areas is not scarce.
Population might just stabilize at some point, and then there's not much of a driver to expand off of our planet (apart from some resource mining, and other activities.)
Food and energy are not what defines scarcity any more.
If you want to pay the mortgage, have a fulfilling job, have time to spend with your family, and give your child a good start in life, you can't have 8 kids in a middle class family.
Sometimes 1 is the right number if you want your child to be successful and have enough free time to enjoy life yourself.
That IS resource constraint, the resource just isn't food.
The replacement rate is a little above 2 children in the modern world. Three kids is a burden for a lot of people.
It's pretty clear that the major driver is education and freedom of career choice for women. The UN has lots of data supporting that. Industrialization and changing attitudes toward children have also played a role.
My paternal grandfather was a farmer. He had 20 children who survived to adulthood. By two wives, the second having been the nursemaid. As I understand it, all of the children worked. Basically as soon as they could walk. Girls focused on childcare and housework, and boys on farm work. If they'd been living in a city, the boys would have had factory jobs.
So anyway, that's how you raise many children. That or be wealthy, of course. But current expectations, social norms, and laws make that impossible. Except perhaps for farm families, where substantial child labor remains legal.
Education comes with higher life standards. You want your kids to have their own rooms instead of whole family living in single-room shack, education for them etc.
"Freedom of career" for women is more like freedom to have to work. It's hard to raise a family on a single salary. Previously, a woman would work at home and husband would work outside. Now both of them have to work outside of the house to pay for appliances that do stuff back at home.
IMO one of the top issues is housing cost. Increasing specialisation, both parents having to work and urbanisation means people are crammed into more and more condensed cities. Space comes at expense. Children need space. Cheaper space out of the city means more transport costs and/or less job opportunities and likely lower wage. All in all, children is damn expensive.
Yes, it's true that (at least in the US) greater career choice for women has come with declining real wages. So that now, both partners need to work. Some argue that effectively doubling the workforce has played a major role. Or that people just expect to have more stuff. But the power of unions to maintain livable wages has eroded over the same time frame. And maybe it's all connected.
What's the resource constraint then if it's not food, energy, or shelter?
People want to buy more stuff? Hardly a requirement of years gone by.
People want more free time? Doubtful, otherwise people would work less and buy less stuff - which we don't see. People keep getting more productive, but they just funnel that into a more expensive lifestyle rather than cutting back on work.
I don't think the reasons are simple (or even the same between people) but I don't think it's dominated by resource constraints.
I know software engineers with no children and school teachers with four. Very different lifestyles, but all middle class. And I don't think resource constraints factored heavily into their decision making.
The resource constraints now are time and location. It's affordable to buy houses in a lot of places, just not so many that have access to good jobs and schools. So people prioritize the latter and sacrifice their time by commuting for work.
Since both parents now work, often with lengthy commutes, there isn't a whole lot of person-hours left to spend with the children. That means people have fewer of them.
When the kids get older and it's time to send them to university, well, that's something which has gone backwards in affordability. The cost of a university degree has shot through the roof. How could anyone afford to send 3 kids to university these days, let alone 8?
I think both parents (or especially the woman) working is probably the big part of it. But I don't think many people factor the cost of university degrees into their decision (whether they should is another matter)
Never mind traditionally, this is still true, even in the most egalitarian countries (Scandinavian countries).
Women have to choose between family and career, men don't really have to do that. The biggest driver behind the gender pay gap is the difference between women with children and women without. Somehow we haven't solved the issue that it's a cost borne primarily by women.
I think the current answer is quality - people want the best for their kids including a future or they won't have them otherwise. They may feel that their lifestyle consume too much time, that they can't afford what they need, or just that they and their family situation would make poor parent(s) for whatever reason. And this is peripheral to adoption vs reproduction.
Kids have turned from a resource like they were to farm families to an expense and an increasing one at that - and I don't mean in a "kids these days" sort of way - the world changed and not people. Which leaves children to be had by those who want to have them for the sake of having them - some sort of enjoyment or sense of obligation.
There are plenty of other drivers to expand off Earth:
1. Backup in case things go wrong (meteor strike, end of the Earth, nuclear war, mass plague, AI/robot revolt)
2. Outright inability to live alongside other cultures and societies/groups. Just like throughout history, some beliefs will also be controversial at best/illegal at worst, and while in the past finding a unoccupied area on Earth was practical, that's not really the case now. So space it is.
3. Science/academic study. Robots are neat, but there are some things it's better to send humans for, and a fair few scientists would probably rather be out there exploring than sat behind a computer screen.
4. General boredom/tourism/whatever.
5. Environmental concerns. Not just resource mining, but let's face it... eventually a lot of environmentally unfriendly industrial processes will probably work better in a place with no atmosphere/biosphere to ruin.
The people left to live on earth will be more and more tied to doing mindless jobs. I think there are a lot of people that would be excited to start a new community on Mars, get paid to, basically exist and build homes (pods) and connect those pods to additional pods. The act of mining will have meaning again beyond helping someone else get rich off bitcoin.
> how does Fortnite demonstrate “infinite growth”?
Fortnite makes money by selling digital in-game goods. Their revenues could grow infinitely without their material footprint expanding one iota. What they demonstrate is not infinite growth, but the capacity for infinite growth in a finite universe.
Value, at the end of the day, is subjective. Growth is a measure on this subjective value. It is not a measure on material inputs.
That's not infinite growth. There are only a finite number of humans on earth who could possibly play the game, and many of those either have no interest or can't afford to do so. And, of all those potential players, each of them only has finite disposable income. So there is a hard upper limit on their revenue, without growth in world population (to increase population of potential players) or growth in the world economy (to increase disposable income of those players). So, Fortnite is subject to the same finite growth limitations as every other business.
> There are only a finite number of humans on earth who could possibly play the game, and many of those either have no interest or can't afford to do so. And, of all those potential players, each of them only has finite disposable income. So there is a hard upper limit on their revenue
The proposed metric, a product of population and incomes, is unbounded (in aggregate). Population isn’t. But nominal incomes, a function of the unbounded money supply, is. Real incomes are trickier, but they--too--are unbounded. It just requires some fraction of the basket be immaterial. As long as that component grows sufficiently, the real value of the basket–which, again, is subjective–grows.
This isn't some edge-case philosophy, but a well-recognized effect of the subjective nature of value. (The physicist in me points out that the observable universe has, based on known physics, a finite computational capacity, but that objection merely illustrates the absurdity of proposing a practical upper bound on growth.)
We're used to thinking of production as making cars and ships. Those activities represent a falling share of human activity (weighted by value). To illustrate, witness the falling material intensity and energy intensity of GDP growth.
You two comments strongly remind me of what is currently happening in Venezuela. Having bigger numbers on your money or bank account isn't necessarily a good metric.
Anyway, let me rephrase your argument to make sure I understand it correctly:
There exists resource sinks like Fortnite, media & alike. Thus regardless of how much growth we will have / more efficient we become, even more would be better so we can spend it on those sinks.
This seems technically correct, but I doubt this is how our civilization should spend the finite amount of resources available.
