Figure out why don’t we build one city with one billion population - Bigger cities will probably accelerate tech progress, and other types of progress, as people are not forced to choose between their existing relationships and the place best for their career - Assume end-to-end travel time must be below 2 hours for people to get benefits of living in the same city. Seems achievable via intra-city (not inter-city) bullet-train network. Max population = (200 km/h * 2h)^2 * (10000 people/km^2) = 1.6 billion people - Is there any engineering challenge such as water supply that prevents this from happening? Or is it just lack of any political elites with willingness + engg knowledge + governing sufficient funds? - If a govt builds the bullet train network, can market incentives be sufficient to drive everyone else (real estate developers, corporate leaders, etc) to build the city or will some elites within govt need to necessarily hand-hold other parts of this process?
I agree VR might be one-day be able to do this (make online meetings as good as in-person ones). As of 2025, bullet trains are more proven tech than VR. I’d be happy if both were investigated in more depth.
Cities of 10Ms exist, there is always some difficulty in scaling, but scaling 1.5-2 OOMs doesn’t seem like it would be impossible to figure out if particularly motivated.
China and other countries have built large cities and then failed to populate them
The max population you wrote (1.6B) is bigger than china, bigger than Africa, similar to both American Continents plus Europe .
Which is part of why no one really wants to build something so big, especially not at once.
Everything is opportunity cost, and the question of alternate routes matters alot in deciding to pursue something. Throwing everything and the kitchen sink at something costs a lot of resources.
Given that VR development is currently underway regardless, starting this resource intense project which may be made obsolete by the time it’s done is an expected waste of resources. If VR hit a real wall that might change things (though see above).
If this giga-city would be expected to 1000x tech progress or something crazy then sure, waste some resources to make extra sure it happens sooner rather than later.
Tl;dr:
Probably wouldn’t work, there’s no demand, very expensive, VR is being developed and would actually be able to say what you’re hoping but even better
It could be built in stages. Like, build a certain number of bullet train stations at a time and wait to see if immigrants + real estate developers + corporations start building the city further, or do the stations end up unused?
I agree there is opportunity cost. It will help if I figure out the approx costs of train networks, water and sewage plumbing etc.
I agree there are higher risk higher reward opportunities out there, including VR. In my mind this proposal seemed relatively low risk so I figured it’s worth thinking through anyway.
no demand
This is demonstrably false. Honestly the very fact that city rents in many 1st world countries are much higher than rural rents proves that if you reduced the rents more people would migrate to the cities.
Building infrastructure is expensive. It may or may not be used, and even if used it may not be worthwhile.
R&D for VR is happening regardless, so 0 extra cost or risk.
Would you invest your own money into such a project?
“This is demonstrably false. Honestly the very fact that city rents in many 1st world countries are much higher than rural rents proves that if you reduced the rents more people would migrate to the cities.”
Sure, there is marginal demand for living in cities in general. You could even argue that there is marginal demand to live in bigger vs smaller cities.
This doesn’t change the equation: where are you getting one billion residents—all of Africa? There is no demand for a city of that size.
Would you invest your own money in such a project?
If I were a billionaire I might.
I also have (maybe minor, maybe not minor) differences of opinion with standard EA decision-making procedures of assigning capital across opportunities. I think this is where our crux actually is, not on whether giant cities can be built with reasonable amounts of funding.
And sorry I won’t be able to discuss that topic in detail further as it’s a different topic and will take a bunch of time and effort.
1 is going to take a bunch of guesswork to estimate. Assuming it were possible to migrate to the US and live at $200/mo for example, how many people worldwide will be willing to accept that trade? You can run a survey or small scale experiment at best.
What can be done is expand cities to the point where no more new residents want to come in. You can expand the city in stages.
I don’t think the US wants to triple the population with immigrants, and $200/month would require a massive subsidy. (Internet says $1557/month average rent in US)
How many people would you have to get in your city to justify the progress?
100 Million would only be half an order of magnitude larger than Tokyo, and you’re unlikely to get enough people to fill it in the US (at nearly a third of the population, you’d need to take a lot of population from other cities)
How much do you have to subsidize living costs, and how much are you willing to subsidize?
If I understand correctly it is possible to find $300/mo/bedroom accommodation in rural US today, and a large enough city will compress city rents down to rural rents. A govt willing to pursue a plan as interesting as this one may also be able to increase immigrant labour to build the houses and relax housing regulations. US residential rents are artificially high compared to global average. (In some parts of the world, a few steel sheets (4 walls + roof) is sufficient to count as a house, even water and sewage piping in every house is not mandatory as long as residents can access toilets and water supply within walking distance.)
(A gigacity could also increase rents because it’ll increase the incomes of even its lowest income members. But yeah in general now you need to track median incomes of 1B people to find out new equilibrium.)
Is there any engineering challenge such as water supply that prevents this from happening? Or is it just lack of any political elites with willingness + engg knowledge + governing sufficient funds?
That dichotomy is not exhaustive, and I believe going through with the proposal will necesarily make the city inhabitants worse off.
Humans’ social machinery is not suited to live in such large cities, as of the current generations. Who to get acquainted with, in the first place? Isn’t there lots of opportunity cost to any event?
Humans’ biomachinery is not suited to live in such large cities. Being around lots and lots of people might be regulating hormones and behaviour to settings we have not totally explored (I remember reading something that claims this a large factor to lower fertility).
Centralization is dangerous because of possibly-handmade mass weapons.
Assuming random housing and examining some quirk/polar position, we’ll get a noisy texture. It will almost certainly have a large group of people supporting one position right next to group thinking otherwise. Depending on sizes and civil law enforcement, that may not end well.
After a couple hundred years, 1) and 2) will most probably get solved by natural selection so the proposal will be much more feasible.
Sorry I didn’t understand your comment at all. Why are 1, 2 and 4 bigger problems in 1 billion population city versus say a 20 million population city?
I’d maintain that those problems already exist in 20M-people cities and will not necessarily become much worse. However, by increasing city population you bring in more people into the problems, which doesn’t seem good.
Got it. I understood what you’re trying to say. I agree living in cities has some downsides compared to living in smaller towns, and if you could find a way to get the best of both instead it could be better than either.
Project idea for you
Figure out why don’t we build one city with one billion population
- Bigger cities will probably accelerate tech progress, and other types of progress, as people are not forced to choose between their existing relationships and the place best for their career
- Assume end-to-end travel time must be below 2 hours for people to get benefits of living in the same city. Seems achievable via intra-city (not inter-city) bullet-train network. Max population = (200 km/h * 2h)^2 * (10000 people/km^2) = 1.6 billion people
- Is there any engineering challenge such as water supply that prevents this from happening? Or is it just lack of any political elites with willingness + engg knowledge + governing sufficient funds?
- If a govt builds the bullet train network, can market incentives be sufficient to drive everyone else (real estate developers, corporate leaders, etc) to build the city or will some elites within govt need to necessarily hand-hold other parts of this process?
Vr might be cheaper
I agree VR might be one-day be able to do this (make online meetings as good as in-person ones). As of 2025, bullet trains are more proven tech than VR. I’d be happy if both were investigated in more depth.
A few notes on massive cities:
Cities of 10Ms exist, there is always some difficulty in scaling, but scaling 1.5-2 OOMs doesn’t seem like it would be impossible to figure out if particularly motivated.
China and other countries have built large cities and then failed to populate them
The max population you wrote (1.6B) is bigger than china, bigger than Africa, similar to both American Continents plus Europe .
Which is part of why no one really wants to build something so big, especially not at once.
Everything is opportunity cost, and the question of alternate routes matters alot in deciding to pursue something. Throwing everything and the kitchen sink at something costs a lot of resources.
Given that VR development is currently underway regardless, starting this resource intense project which may be made obsolete by the time it’s done is an expected waste of resources. If VR hit a real wall that might change things (though see above).
If this giga-city would be expected to 1000x tech progress or something crazy then sure, waste some resources to make extra sure it happens sooner rather than later.
Tl;dr:
Probably wouldn’t work, there’s no demand, very expensive, VR is being developed and would actually be able to say what you’re hoping but even better
It could be built in stages. Like, build a certain number of bullet train stations at a time and wait to see if immigrants + real estate developers + corporations start building the city further, or do the stations end up unused?
I agree there is opportunity cost. It will help if I figure out the approx costs of train networks, water and sewage plumbing etc.
I agree there are higher risk higher reward opportunities out there, including VR. In my mind this proposal seemed relatively low risk so I figured it’s worth thinking through anyway.
This is demonstrably false. Honestly the very fact that city rents in many 1st world countries are much higher than rural rents proves that if you reduced the rents more people would migrate to the cities.
Lower/Higher risk and reward is the wrong frame.
Your proposal is high cost.
Building infrastructure is expensive. It may or may not be used, and even if used it may not be worthwhile.
R&D for VR is happening regardless, so 0 extra cost or risk.
Would you invest your own money into such a project?
“This is demonstrably false. Honestly the very fact that city rents in many 1st world countries are much higher than rural rents proves that if you reduced the rents more people would migrate to the cities.”
Sure, there is marginal demand for living in cities in general. You could even argue that there is marginal demand to live in bigger vs smaller cities.
This doesn’t change the equation: where are you getting one billion residents—all of Africa? There is no demand for a city of that size.
If I were a billionaire I might.
I also have (maybe minor, maybe not minor) differences of opinion with standard EA decision-making procedures of assigning capital across opportunities. I think this is where our crux actually is, not on whether giant cities can be built with reasonable amounts of funding.
And sorry I won’t be able to discuss that topic in detail further as it’s a different topic and will take a bunch of time and effort.
Our cruxes is whether the amount of investment to build one has a positive expected return on investment, breaking down into
If you could populate such a city
Whether this is a “try everything regardless of cost” issue, given that a replacent is being developed for other reasons.
I suggest focusing on 1, as it’s pretty fundamental to your idea and easier to get traction on
1 is going to take a bunch of guesswork to estimate. Assuming it were possible to migrate to the US and live at $200/mo for example, how many people worldwide will be willing to accept that trade? You can run a survey or small scale experiment at best.
What can be done is expand cities to the point where no more new residents want to come in. You can expand the city in stages.
Definitely an interesting survey to run.
I don’t think the US wants to triple the population with immigrants, and $200/month would require a massive subsidy. (Internet says $1557/month average rent in US)
How many people would you have to get in your city to justify the progress?
100 Million would only be half an order of magnitude larger than Tokyo, and you’re unlikely to get enough people to fill it in the US (at nearly a third of the population, you’d need to take a lot of population from other cities)
How much do you have to subsidize living costs, and how much are you willing to subsidize?
If I understand correctly it is possible to find $300/mo/bedroom accommodation in rural US today, and a large enough city will compress city rents down to rural rents. A govt willing to pursue a plan as interesting as this one may also be able to increase immigrant labour to build the houses and relax housing regulations. US residential rents are artificially high compared to global average. (In some parts of the world, a few steel sheets (4 walls + roof) is sufficient to count as a house, even water and sewage piping in every house is not mandatory as long as residents can access toilets and water supply within walking distance.)
(A gigacity could also increase rents because it’ll increase the incomes of even its lowest income members. But yeah in general now you need to track median incomes of 1B people to find out new equilibrium.)
That dichotomy is not exhaustive, and I believe going through with the proposal will necesarily make the city inhabitants worse off.
Humans’ social machinery is not suited to live in such large cities, as of the current generations. Who to get acquainted with, in the first place? Isn’t there lots of opportunity cost to any event?
Humans’ biomachinery is not suited to live in such large cities. Being around lots and lots of people might be regulating hormones and behaviour to settings we have not totally explored (I remember reading something that claims this a large factor to lower fertility).
Centralization is dangerous because of possibly-handmade mass weapons.
Assuming random housing and examining some quirk/polar position, we’ll get a noisy texture. It will almost certainly have a large group of people supporting one position right next to group thinking otherwise. Depending on sizes and civil law enforcement, that may not end well.
After a couple hundred years, 1) and 2) will most probably get solved by natural selection so the proposal will be much more feasible.
Sorry I didn’t understand your comment at all. Why are 1, 2 and 4 bigger problems in 1 billion population city versus say a 20 million population city?
I’d maintain that those problems already exist in 20M-people cities and will not necessarily become much worse. However, by increasing city population you bring in more people into the problems, which doesn’t seem good.
Got it. I understood what you’re trying to say. I agree living in cities has some downsides compared to living in smaller towns, and if you could find a way to get the best of both instead it could be better than either.