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Exponential population growth is fundamentally unsustainable. Given a population growth rate of about 2% per year, like it was in the 1960s, an average mass of 60 kg per person, current world population of 7 billion, and a total mass of the universe of 3x10^52 kg, we can calculate the amount of time before humans consume the entire universe, including dark matter. It's a little under 5000 years, far shorter than the record of human history.

So, this is a fact: we cannot grow exponentially for very long. Also a fact: humans have survived the vast majority of human history with near zero population growth, if we consider human history to be 200 millennia old and population growth to be a factor of a million during that time, average growth is 0.007% per year.

Economic growth is also the wrong thing to measure. Surely something else, like quality of life, would be more appropriate. You say that "no amount of economic/financial manipulation has helped [Japan]" but does Japan really need help, or are their citizens enjoying a relatively high quality of life?

"...are their citizens enjoying a relatively high quality of life?' I would say yes.

To me, the question is: can their high quality of life be maintained if there is no economic growth? Is it possible to print money/borrow indefinitely to support this quality of life?

Especially with regards to the article, I think these are valid questions.

> Is it possible to print money/borrow indefinitely to support this quality of life?

Why do you need to print or borrow money to sustain a quality of life?

Some people think money has inherent value..

They would be wrong.

Due to technological progress, the amount of money and resources required to maintain a constant quality of life has decreased over the years. So you could in fact maintain quality of life even during economic contraction, as long as resources permit.

My question is: why do you suspect that economic growth is necessary for quality of life? What is the exact connection there that you are thinking about?

Great questions. Thanks. Looking at their economy as it is, they are borrowing massively with essentially 0 growth. The government is doing this in an effort to prop up the economy and spur growth.

If they were to stop borrowing money without a substantial leap in technological progress, would the economy go into a deep recession? I do not know enough about economics to say, but I am basing my assumptions around this reasoning. Am I missing something?

I'm then assuming that if the country went into a deep recession, that quality of life for the average person would decrease.

> The government is doing this in an effort to prop up the economy and spur growth.

How so?

From where I sit, Japan's borrowing is funding infrastructure rebuilding and quantitative easing. The infrastructure, including energy production, is necessary for future economic and human activity. Quantitative easing combats deflation and keeps monetary policy functional when interest rates are low. This borrowing looks neither unsustainable nor does it look like a measure to artificially prop up the economy.

> If they were to stop borrowing money without a substantial leap in technological progress, would the economy go into a deep recession?

If you suddenly stop borrowing money, it would cause economic turmoil, just because everything is economically connected and everyone's economic forecasts would change. The borrowing is being used to support QE which causes inflation, without it Japan could be at risk of deflation. Deflation would mean that goods and services would get cheaper (and maintaining quality of life would also get cheaper), but there are also negative consequences—people who save money win, people who borrow money lose, people who invest money have a hard time making good investments, lack of investment causes problems down the road, etc.

You haven't addressed the question at all.

To reiterate, the question was:

Why do you think quality of life is tied to economic growth? What do you base that assumption on?

> calculate the amount of time before humans consume the entire universe

I've heard this same argument made using energy instead of mass. That article correlated economic growth with increased energy usage. It does make sense, our universe might be expanding but it is finite.

However, what if this is a social and not a physics problem? Maybe more and more new people are required to keep human social structures functioning optimally. Maybe the solution is virtual reality.

> Given a population growth rate of about 2% per year, like it was in the 1960s, an average mass of 60 kg per person, current world population of 7 billion

Economic growth in developed countries is driven by population growth, and this is why they all have a decent amount of immigration, to sustain that growth. In developing countries, they can grow by development - adding more subsistence farmers doesn't really grow the economy.

Australia has just taken the record for the longest period without a recession (26ish years), and this has been done on the back of immigration - since 1999, we've increased our population by a quarter, and our birthrate is only replacement-level. Population growth in developed countries != population growth globally.

> Population growth in developed countries != population growth globally.

Right, and both are unsustainable long-term.

I'd say a lot of the growth has been by exporting dirt and food to China and other Asian countries. This made Australia resistant to the GFC crashes because our raw materials were in great demand. It was also regardless of immigration as other countries with similar levels of immigration did not have the same economic success.

Mining is only 7-8% of our economy. We survived both the GFC and the recent years of mining downturn. Mining isn't a small part of it, but it's not really the key player in our economy. Agriculture is much bigger, but still, the reason why we import so many humans[1] is to keep our economy growing. Immigration isn't the only thing that can affect an economy, but with an ageing population, bringing in new youthful blood helps keep the workforce growing.

[1] The only large Western nations with higher immigration rates are Spain and, surprisingly, Norway.

In college I had an econ friend who said that there's basically only three ways to grow an economy: more workers, better technology or more capital.

If you look at technology, then I think "yes!" it has improved the economy. Look at engines and trains and telecommunications. The first world economy today, per person, is rip-roarin' compared to 100 years ago.

Many western economies haven't noticed the decline in the birth rate yet because of so many immigrants. Japan is unique in that they are a modern country, with a declining birth rate, but very low immigration.

doesn't declining population mean also lower expenses on infrastructure and everything?

No because you might need a lot of infrastructure to keep up with the fact that the largest part of your population is old.

Populations don't decline uniformly and people don't naturally optimize for infrastructure use and the best use of existent resources.

You don't have to even wait for population decline, we already have more unoccupied homes in the US than homeless by an order of magnitude, but all those homes are in "dead" areas where industry or resource extraction came and went. Now those houses and all the infrastructure around them decay without use, while elsewhere infrastructure is overburdened with concentrated people.

If anything, declining population means more per-capita expense on infrastructure, and the per-capita costs of maintaining current infrastructure (at least in the US) is out of control.[1]

[1]: https://www.strongtowns.org/journal/2017/6/4/this-is-why-inf...

This is basically conventional wisdom.

Why do you think politicians say they will sort out immigration, but then encourage even more immigrants? They want more workers.

I am not so convinced, given that our jobs are all supposed to be automated soon, we shouldn't have to rely on more humans to grow economically.

In the UK they claim we need mass immigration for growth, but jobs that teenagers used to do are now being done by grown adults, so I don't believe it. We also apparently have terrible productivity compared to other countries. I think that if we stopped relying on extra humans, productivity would suddenlg rocket.

How do you reconcile this with what is happening in Japan? Do you think huge amounts of automation would fix their problems? Isn't much of their manufacturing already automated?

Not to mention their extremely widespread usage of vending machines, which, Vox (from YouTube) posits is a result of their shrinking workforce.

Reasons vending machines are popular in Japan

- they were an easy place to get beer before convenience stores sold alcohol or became open 24/7 (this is a bit before my time so maybe someone else can elaborate)

- a vending machine requires less space than a store.

- there is not a large difference in price buying from a vending machine or convenience store (10 yen or so).

- It is very hot in summer and very cold in winter, so people like having access to a hot or cold drink.

- a lot of people operate on a tight schedule, so their only "free time" might be when they are walking between places (home and train station, train station and work etc)

- vending machines are useful in a disaster. I believe they will give out free drinks in an emergency.

Slightly OT but I once had a Japanese vending machine deliver a cardboard can printed with an apology when it was out of the drink I requested.

The can had a plastic lid with coins in it, returning the amount I had deposited, and the cardboard can contained an instant cold pack, presumably to assist me with managing the heat while finding another vending machine.

Some manufacturing jobs are automated. I'm talking about the next phase.

Is Japan really in that bad of shape? Their rural areas are dying out, but that is the natural trend towards peak urbanization. The larger cities are vibrant, and while their work life balance is (to put it lightly) completely wack, there are plenty of major international players in a lot of markets of Japanese origin - Toyota, Sony, Nintendo, Subaru, etc.

Those companies are growing or at worst sustaining at globally satiated production, to the best of my understanding few go hungry, technological adoption is extremely high, and homelessness and crime are low. Per-capita they keep ending off better off year over year by staying put while everything else gets cheaper. Their whole economy looks like it is contracting with the population decline but nobody is suffering a lack of supply availability to meet their demands for it. Top it off with the giant entertainment sector amount of culture they output globally and that does not ring of doomed society.

My intuition tells me that productivity per capita has been increasing; we have not been relying on population growth alone to grow the economy.

The catch is that the increased production is not distributed equitably. For the average (more productive) worker, the things that they need such as health and housing are not any 'cheaper'. So where is their 'share'?

As productivity increases, credit expands to capture it. This is how, ultimately, those with the capital end up with the increased productivity.

Just a thought.

I'm no historian but I believe that there is a precedent for the current demographic trends - the late Roman Empire. From what I've read, birth rates didn't sufficiently outpace infant mortality rates during the late days of Roman rule, which may have been a contributing factor to the fall of the Empire.

This video seems relevant: https://www.youtube.com/watch?v=FACK2knC08E

According to Hans Rosling we've reached "peak child", meaning we're almost at 2 children per woman globally. This means population will continue to grow for a few years as globally there are more children than adults but will stabilize after that around the ~11 billion mark. And as long as we stay at that "peak child" number we won't go any further. I really recommend his videos if you haven't seen them.

When you have population growth (or non-native settlers), they prop up the old. It's a pyramid scheme.

> When you have population growth (or non-native settlers), they prop up the old. It's a pyramid scheme.

It's literally a pyramid scheme: the population pyramid is supposed to have a broad base, but today it's upside down.

And if it is not occasionally reset by natural catastrophes it will be reset by man-made ones. In the 1980ies we feared man, today we are blindly growing towards destruction (by population growth domestic or imported). Some people cite Japan as an example of failure, I see them as an example of sustainability: they abstain from the quick and easy wealth fix that could be had by pyramid-scheming.

Productivity growth per capita (= "economic growth even without population growth") has been happening since the industrial revoluation, and lately it's moved more and more into immaterial / less resource intensive domains.

You don't seem to present any arguments as to why it wouldn't happen without population growth. It has been rather self-sustaining.

(A different questionis whether we should aim for economic growth - given our biggest problem now is climate change).

Could this be a reflection of our monetary system (the fact that we cannot possibly repay all the money because there is interest that is owed to the lenders, and where does that extra interest come from? The lenders!)? This means we need more people to earn more money to pay it back ad nauseum leading to an exponential problem? I'm not an economic expert but believe the basis of the above is rooted in reality but happy to learn more if someone can correct me!

That's only true if the interest payment is larger than the income that can be made available to pay it.

If you live in Greece then, yes, this is a bit of an issue. The solution there is likely to be some form of writing down of the debt.

what you described is essentially a global ponzie scheme. and that's what it is at the bottom line - the growth feeds on itself - no more growth - everything crashes.

is that sustainable or even reasonable by any standard - the answer is an obvious "no". but it benefits the powerful.

No. The error that you have made is confusing stocks with flows. Your problem would be true under two circumstances - if all debts had to be paid at once, or if money disappeared when spent.

But when you introduce the time dimension, the system works. The money supply is a 'stock' of some quantity, but payments (principal and interest) occur over time, making them a 'flow'. Those payments will then generally be spent back into the system, which circulates (all expenditure is someone else's income). This circulation is measured as the 'velocity of money'.

So interest isn't a problem ultimately, but the increasing accumulation of wealth by the most wealthy may become more and more of an issue.

Is economic growth necessary? Is it valid that no growth / slow growth is the same thing as stagnation? What does a world look like when the population is staying roughly constant, with births and deaths in balance?

Japan has been in a situation like that for a while now. Instead of poo-pooing it as a long recession, maybe the rest of the world should try to learn from it.

I think we covered this in my Econ courses.