This Can't Go On

Very interesting post. I'm interested in this argument about atoms and growth.

• "Let's say the world economy is currently getting 2% bigger each year.⁵ This implies that the economy would be doubling in size about every 35 years.⁶
• If this holds up, then 8200 years from now, the economy would be about 3*10⁷⁰ times its current size.
• There are likely fewer than 10⁷⁰ atoms in our galaxy,⁷ which we would not be able to travel beyond within the 8200-year time frame.⁸
• So if the economy were 3*10⁷⁰ times as big as today's, and could only make use of 10⁷⁰ (or fewer) atoms, we'd need to be sustaining multiple economies as big as today's entire world economy per atom."

I find this connection between GDP and atoms a bit obscure. It might also seem weird to think that today there is more GDP in $ than there are stars in the Milky Way, but these two things don't seem comparable to me.  There are 10^50 atoms on Earth (apparently).  Maybe we only have access to 10^18 of these atoms or something. World GDP is 10^18 Zimbabwean cents. So, each atom is producing one Zimbabwean cent of value. I don't know whether this is or isn't plausible. 

Really what we're concerned about is whether we can extract subjective wellbeing from different arrangements of atoms. Once we start thinking about digital minds  and VR, I don't have a strong intuition about how much subjective wellbeing we can squeeze out of a given number of atoms. 

One reason we shouldn't be too surprised that most scientific progress is recent, years-wise is that a very simple model of scientific progress might be that you need X people (or X smart, literate people etc) thinking for Y moments to have a Z% chance of coming up with a scientific insight. 

And if you measure time anthropically rather than geologically, estimates suggest that >~20% of people who have ever lived were born after 1650. The fraction is likely higher if you measure by human-moments rather than number of humans (since dead infants don't make many scientific insights), and higher still if you only count literate or otherwise knowledgeable humans with ample free time. 

I’m trying to reconcile claims about continued population growth with what we often see in natural systems, where populations tend to move toward some form of equilibrium over time.

In ecology, for example, predator–prey dynamics (like deer and wolves) create feedback loops that prevent indefinite growth. While humans obviously don’t follow the same biological constraints, it seems we do have our own balancing mechanisms—economic, social, and cultural.  As well as human caused climate change/pollution can also be affecting the ability for women to become pregnant?

For instance, in many developed countries, declining fertility rates suggest that as societies become more urbanized, educated, and economically stable, population growth slows or even reverses. That looks less like “explosive growth indefinitely” and more like a transition toward stabilization.

So my question is:
To what extent do EA models account for these kinds of equilibrium dynamics—especially demographic transitions and declining birth rates?
And under what assumptions would continued large-scale growth still hold?

Thank you for writing this.

After I first read all the material on Cold Takes (well, I skimmed it--but only because you asked me to!) I figured that I wouldn't bother to keep up with new stuff as it comes out; what good would it do me? It was written for a general audience and I am not a general audience.

That attitude lasted until around the third time I found myself linking to or quoting from your blog as a starting point for conversations with the vastly inferentially removed. And, I've known about the blog less than a week.

Needless to say I'll be keeping up with what you write.

The argument here by appealing to too few atoms in the galaxy as a limit to economic growth is poor physics. The fundamental  limit to economic value is that of information density.

Most of the galaxy (and universe) is entirely devoid of matter. Visible matter is exceedingly rare.  But not energy. And energy may be assembled into economically valuable patterns, most clearly as information.  E.g. a radio transmission of an opera to listeners does not require consumption of  atoms. 

An upper bound for information density is given by https://en.wikipedia.org/wiki/Bekenstein_bound and it is exceedingly large, so large that there isn't a fundamental limit on the time frames considered here. 

Likewise, appeals to limits to energy emitted from all stars is considerably lower than the total energy content of the galaxy, by tremendous orders of magnitude. 

As this article is looking at the far-term future, then outlandish possibilities (to us) must also be considered;  a very far advanced civilization might consist mostly of a dance of electromagnetic radiation.  Indeed we're clearly on that path with wifi/5G. 

TLDR: economic growth hasn't a fundamental limit per the  arguments here. 

I miss a clear definition of economic growth here, and the discussion strongly reminds me of the environmental resources focused critique of growth that has started with 1970's Club of Rome - Limits to Growth, there might be value to examine the huge literature around that topic that has been produced ever since on such topics.

Economic growth = increase in market value, is a typical definition.

Market value can increase if we paint the grey houses pink, or indeed if we design good computer games, or if we find great drugs to constantly awe use in insanely great ways without downsides. Or maybe indeed if we can duplicate/simulate brains which derive lot of value, say, literally out of thin air - and if we decide to take into account their blissful state also in our growth measure.

If we all have our basic needs met, and are rich way beyond it, willingness to pay for some new services may become extremely huge; even for the least important services - merely as we have nothing to do with our wealth, and as we're willing to pay so little on the margin for the traditional 'basic' goods who are (in my scenario assumed to be) abundant and cheaply produced.

So the quantitative long-run extent of "economic growth" then becomes a bit an arbitrary thing: economic growth potentially being huge, but the true extra value possibly being limited.

'Economic growth' may therefore be too intangible, too arbitrary a basis for discussing the nature of long-run fate of human (or what ever supersedes us) development.

Maybe we should revert back to directly discussing limits to increase in utility (as come comments here already do).

Could you provide some evidence that this rate of growth is unusual in history?   I mean it wouldn't shock me if we looked back at the last 5000 years and saw that most societies real production grew at similar rates during times of peace/tranquility but that resulted in small absolute growth that was regularly wiped out by invasion, plague or other calamity.  In which case the question becomes whether or not you believe that our technological accomplishments make us more resistant to such calamities (another discussion entirely).

Moreover, even if we didn't see similar levels of growth in the past there are plenty of simple models which explain this apparent difference as the result of a single underlying phenomenon.  For instance, consider the theory that real production over and above subsistence agricultural level grows at a constant rate per year.  As this value was almost 0 for the past 5,000 years that growth wouldn't be very noticeable until recently.  And this isn't just some arbitrary mathematical fit but has a good justification, e.g., productivity improvements require free time, invention etc.. etc.. so only happens in the percent of people's time not devoted to avoiding starving.


Also, it's kinda weird to describe the constant rate of growth assumption as business as usual but then pick a graph where we have an economic singularity (flat rate of growth gives a exponential curve which doesn't escape to infinity at any finite time).  Having said all that, sure it seems wrong to just assume things will continue this way forever but it seems equally unjustified to reach any other conclusion.

A bit late to the discussion here, but I wanted to re-emphasize the slightly nearer term limits that Holden brought up by Tom Murphy in his "Do The Math" blog, first presented a decade ago:
https://dothemath.ucsd.edu/2011/07/galactic-scale-energy/

This is formalized in Chapters 1&2 in a textbook he just released: https://escholarship.org/uc/item/9js5291m

The argument goes 1) there is a finite amount of energy available, limited by solar capacity, 2) decoupling of energy from the economy is ultimately limited; we can only grow non-energy intense parts of the economy so much as a percentage of the overall economy, 3) space colonization is extremely difficult if not impossible given how inhospitable space is, and therefore 4) economic growth will eventually cease given limited energy and resources.

He also mentions thermodynamic limits to surface heat rejection via blackbody radiation.  We may be able to get around that by moving most computation to space.  Though I imagine that being a harder collective action problem to solve than climate change presently.

Galactic expansion through digital minds may be a possibility that gets around the human biological limits to space expansions, but it's unclear that the timing will line up conveniently.  Our rate of economic expansion may hit hard energy and resources limits before a galactic digital mind expansion, regardless of whether it is possible.

Ultimately I don't see how it's possible to get around the energy limitations.  As long as there are energy requirements for people - biological or otherwise - then it doesn't seem possible to indefinitely shrink the energy intensity of the economy to an arbitrarily small value.

Do we really imagine the future of the economy to be increasingly faster trading of multi-trillion dollar cat holograms?  Is that humanity's destiny?

GDP is a very leaky measure for growth in this context. To see this, consider a utopian scenario with dirt cheap fusion energy powered Star Trek replicators. The marginal cost of most traded goods drops to near zero and GDP tanks (setting aside services).  You have for traditional industry writ large a similar dynamic to that napster triggered for the music industry.

Assuming we don't all die sometime soon and things 'carry on' the solution is likely to lie at least  in part, eventually, in giving up on trying to summarise all of technology in a scalar value.

On another note, as a piece of futurism we see here that technology / the economy is predicted to either:

• Get much bigger.
• Get much smaller.
• Stay about the same.
• Do something else.

This covers just about every possibility, so it can't constitute much evidence on which to update.

[edit: tidied up]

What do you think of a "Matrix" scenario where instead of bothering to capture the entire universe, humans achieve just enough to create a sustainable virtual simulation for a billion people, and then disconnect from the real world forever as AGI robots manage the server farms? Would be especially easy with digital humans, but seems doable with physical humans too.

It seems you already covered this in the extra notes at the end, but I imagine the real graph could look more like this :)

I think humanity entering the digital space could allow growth to keep going much further. We could potentially encode a human into 10^(20-30) atoms.

 

The footnotes are broken here and don't show the preview (which is a very helpful feature for the cold takes article). 

One possible future is stagnation: we'll reach the economy's "maximum size" and growth will essentially stop.

This might be worth rewording for clarity.

In the stagnation scenario the economy will not reach the "maximum size" permitted by the laws of physics (using a given amount of matter, e.g. the solar system), so saying "we'll reach the economy's 'maximum size'" is confusing and could easily be misinterpreted. (I understand you're using the phrase "maximum size" to mean "the largest size that it actually reaches" but I imagine others could easily interpret it to mean "maximum size possible.")

Suggested rewording: "stagnation: growth will slow and stop before the economy reaches its maximum size, i.e. before the economy reaches the limits of efficiency given the laws of physics."

Loved your analogy of the plane on the runway. This describes well a feeling I've had and it can sometimes be lonely! Thanks for the important work you're doing.