# Limits to Calculating Space

There are 10^23 to 10^24 neurons on the planet. The human brain has around 86 billion neurons. World population * human neurons = 10^~10*11^~10 = 10^~21 (slightly less, but let’s round up).

This means the human population can “safely” increase by at least two more orders of magnitude to 1 to 10 trillion, so the ~100 billion that I posit for the Age of Malthusian Industrialism is safe.

However:

1. Perhaps more complicated brains are harder to simulate in principle (e.g. costs of simulating them increases at a faster than linear rate relative to the number of neurons).

2. The Age of Malthusian Industrialism is only temporary. The gears of natural selection will get grinding again, average IQ will rise again, technology will recover, and so will carrying capacity. And unlike today, those high IQ people will be genotypic breeders.

So that’s potentially only around 10-100 planets we can settle assuming we plop down 100 billion on each.

And we might be in danger in our planet merely reaches the trillion person mark (Coruscant/Holy Terra).

1. If we mind upload and turn into ems, the simulators may be forced to shut us down real quick. Just our one planet may be far more than sufficient.

At any rate, interstellar expansion with ems sure is a dicey proposition, seeing as we don’t know how much more room there is down in the basement.

Anatoly Karlin is a transhumanist interested in psychometrics, life extension, UBI, crypto/network states, X risks, and ushering in the Biosingularity.

Inventor of Idiot’s Limbo, the Katechon Hypothesis, and Elite Human Capital.

Apart from writing booksreviewstravel writing, and sundry blogging, I Tweet at @powerfultakes and run a Substack newsletter.

1. anon says

“If we mind upload and turn into ems, the simulators may be forced to shut us down real quick. Just our one planet may be almost sufficient.”

Or slow the rate of calculation to compensate for a greater number of simulated neurons; simulated people would either perceive outside time as moving more quickly or the speed of objects moving through space as increased (and increasing if we continually slow processing to compensate for increasing number of neurons).

As an aside, there is also the possibility that the universe itself is simulated. Of course, that presents an infinite mirror problem where eventually the program eats up intolerably high processing requirements until the entire program collapses; alternatively, no such shutdown would be required if the true universe sports a much faster (or even infinite) speed of light. Perhaps we are simulated and what we see is merely an approximation of the true universe. Or, perhaps the true universe is similar to our own; similar or higher light speed but still less than infinite. In that case, the programmer could slow processing rate, perhaps in a manner that gives the illusion of an accelerating universe at great distances from us (because relative processing rate varies – slows – with distance, giving a relative sense of increased expansion per unit of time with distance from us).

The only problem with this is that the outside observer would perceive our universe as moving more slowly than their own assuming the two universes are identical; for anything of use to be gained from whole universe simulation, either the true universe must have a higher upper limit on calculation speed or our simulated universe is merely a clever illusion, not being entirely simulated at once – something akin to a Boltzman brain where the only true things that are simulated are the mind (constituent parts) and the immediate perceptions of the brain, with the rest being filled in retroactively according to probabilities upon observation (sounds like Quantum Mechanics to me).

Tellingly, dark energy now seems to vary with time. More alien civs = more processing power = greater dark energy content = greater perceived universal expansion rate = slower processing?

https://scitechdaily.com/new-results-show-dark-energy-may-vary-over-time/

And some predict the universe could end at about the same time our star dies due to dark energy. Oh, and dark energy started getting much stronger withing about 400 million years of the formation of our planet (probably closer to our sun’s formation). Hm…do you believe in coincidences? Or is this just an example of the anthropic principle in action?

2. We can all thank Karlin for amply demonstrating that, whatever may be the limits to calculating space, there are at least no limits to nonsense.

3. anonymous coward says

Two points:

a) Thoughts and intelligence aren’t just neurons, and brains aren’t just neural networks. Case in point: unicellular organisms like the paramecium are pretty damn intelligent, all things considered, despite not having a single neuron or any brain at all.

b) Interstellar travel or communication is impossible, sorry. Might as well speculate about Valinor or Narnia.

4. melanf says

Interstellar travel or communication is impossible,

5. Hyperborean says

Before people get outraged, at least read the tag:

Trolling

6. anonymous coward says

Our current understanding of the physical laws of the universe says that traveling or transmitting information faster than light is impossible.

7. melanf says

traveling or transmitting information faster than light is impossible=/=Interstellar travel or communication is impossible

8. neutral says

That does not make interstellar travel impossible, just very slow. The sci fi stories about how people are put into a deep freeze could very well be one way to have practical interstellar travel.

9. anonymous coward says

That does not make interstellar travel impossible, just very slow. The sci fi stories about how people are put into a deep freeze could very well be one way to have practical interstellar travel.

You’d need to wait thousands of years to get to anywhere useful. More importantly, once you get there, you’ll never be able to communicate with Earth, or the Earth with you. So what’s the point? That’s not travel, that’s something else.

Even more importantly, if your ship can sustain life for thousands of years, why bother going to some planet in the first place? You can just park in outer space and build space colonies.

10. neutral says

The early colonists had the same fate, once they left their land most would never come back and would have no more contact with the old world. This may not be everyones cup of tea, but there are enough people who for multiple reasons would want to do such things

11. gate666 says

LOL.

12. anonymous coward says

The early colonists had the same fate, once they left their land most would never come back and would have no more contact with the old world.

What you wrote is bullshit, traffic between colonies and the homeland was extremely heavy. Shipping raw goods from your colonies in exchange for processed goods is the whole point of colonization, after all.

People, goods and information went back and forth all the time, in great frequency. Why else colonize?

13. mal says

Very strong point a) – Human brains and neurons are hugely overrated, there are better ways of doing information processing, and single cell organisms are very well worth considering for inspiration.

However, I disagree with point b). For travel, speed limit of light only really applies to objects in local space time, it doesn’t really apply to space time itself (see – cosmic inflation). Wormholes can possibly be a thing too.

Also, with new confirmations of gravity waves, subluminal warp drives should be rather trivial to construct – just use giant lasers to compress matter to neutron star like densities and then smash the chunks together at gravity wave resonant frequency. Resulting wave amplification should produce enough of a wake for a spaceship to ride in. Won’t get you over light speed, but even at half the light speed should get you around the neighborhood (few decades to the nearest stars). I expect this technology in about 500 years or so.

Communication is even easier. The reason why people say it’s impossible is a direct consequence of a no cloning theorem in quantum mechanics. (Basically, you can’t create perfect clones of quantum states without measuring them first, which of course, causes them to default). Well, true, but that’s just silly talk – who cares about perfect. Imperfect is good enough.

Illustration. Imagine Bob and Alice, and a pair of entangled electrons, magnetic spin up and spin down. Alice packs her electron, an boards a starship and travels 1,000 light years in 50 years, and Bob and Alice agree to measure their pet electrons at a 50 year anniversary. Question – how can Bob tell if Alice is still alive at the anniversary?

He measures his pet electron and gets a spin down. Well, that tells him Alice is spin up, but that doesn’t tell him anything about Alice – it could be because Alice measured her pet electron and got spin up, or it could be random because you get 50/50 chance of being up or down, and Alice could be dead. Hence no information is transmitted, and quantum entanglement is useless for communication in this scenario.

But now imagine if Bob could clone his pet electron. Say, he made 10 clones, with the same quantum state as the original. If Alice is alive and measures her pet electron to spin up, all 10 of Bob’s clones will measure spin down (remember – same quantum state). If Alice is dead, Bob will get about 5 spin ups and spin downs, because Alice’s pet electron is unmeasured and therefore did not cause the probability to default, so you will still get a distribution. And so information is transmitted, faster than light.

Well, stupid science says perfect cloning is prohibited. Bummer. But there are numerical treatments that can get you partially there. So you won’t get clean signal of 5 spin downs vs 10 spin downs. But… with some tricks, if you get to say, 8 spin downs, it’s good enough for me, close enough to 10.

Perfection is prohibited by quantum mechanics, but quantum mechanics says nothing about just eyeballing it. We can use that to dodge the law and build radios.

14. neutral says

No you are full of bullshit, the vast majority colonists if they were even literate did not have any meaningful contact with the other side of the world. Whatever meaningful information they had with the old world would have taken months to get to the average colonist and had no meaningful impact on their lives, they were really living in a new world. The whole point of colonization was that many people were looking to start a new life, the basic behaviour of man that was there at the very start.

15. Anonymous says

Calc error at the beginning. Average num of human neurons = 10^11 not 10^10. Also you must take into account the full neural graph -> 10k synapses on average from each neuron -> 10^15 edge in total.

Redo the math based on total edge (neuron-neuron connection) count.

16. Peripatetic Commenter says

those high IQ people will be genotypic breeders.

Do you mean phenotypic breeders? There could be multiple genotypes leading to the same phenotype.

Eg, Amish and Mormon.

17. Wency says

Agree that it almost certainly won’t happen, but “impossible” is too strong a word. More like we’ll probably never have a level of technology that will make it economically feasible, and people aren’t attached enough to the idea to pursue the massive sacrifices that would be needed to make it happen.

We seem to have mostly maxed out our ability to move goods and people more easily. At this point, I have to be extremely skeptical that there will be a some breakthrough much better than a Project Orion approach. There’s been virtually no progress in this area in 50 years.

A bunch of mostly atheist near-zero-TFR white male nerds think space colonization might happen because they have a quasi-religious attachment to the idea, which gives them false hope and also causes them to project that desire on to other people. But in reality, only a tiny slice of the human population is really drawn to this idea in a way that would make them willing to pursue real sacrifices — say, a cut to their healthcare benefits.

It’s also an idea that provides no real benefits to governments, other than maybe a bit of moral authority among atheist white male nerds. Remember that colonization, and even the Space Race, were justified at the time as supporting the national interest. But sending a bunch of your best and brightest so far away that they will never provide any further benefit is the opposite of “national interest”.

18. Peripatetic Commenter says

A bunch of mostly atheist near-zero-TFR white male nerds think space colonization might happen because they have a quasi-religious attachment to the idea, which gives them false hope and also causes them to project that desire on to other people.

If we could only get the Mormons into space they would probably be able to breed like rabbits.

19. Anon says

What if human brains grow by a factor of 100? Say, if, instead of 10 neurons, each gets 1000 neurons, through CRISPR, IoT, or even blockchain. Enquiring minds want to know.

20. Abelard Lindsey says

Space colonization will happen when the cost of doing it drops low enough that it becomes self-financing by those who want to do it.

21. Wency says

Yeah, I’d agree with this if you replaced “when” with “if”. In other words, the same conditions as the colonization of the Americas. But it can only apply to colonizing our solar system; there’s no way to make interstellar travel self-financing.

22. anonymous coward says

More like we’ll probably never have a level of technology that will make it economically feasible

It’s not about technology. Our current understanding of how space-time works says that FTL travel or communication is impossible and violates the laws of nature. I see no reason to believe these laws of nature will change in the future.

23. prime noticer says

lol. this discussion might as well be a bunch of fat nerds in the basement drinking mountain dew and ‘seriously’ discussing how big their cyber dicks will be in the glorious future.

“Do you think the human cardiovascular system could support my 18 inch phallus? Or would a nanotechnology capillary reflex breakthru in materials science be required for my schlong to erect beyond 24 inches? Wonder what my 36 robo playmate blondes would think.”

it’s fine and good once in a while to think more seriously about the future and future developments, but this stuff is just off the reservation. like the dyson sphere discussions. if you look at some of the math for fusion, you realize in the more efficient reactions, you could build a reactor in outer space that’s maybe 50 to 100 kilometers in diameter, which would give an output equivalent to the sun. which is less difficult? building that? or, you know, encircling the entire sun.

we don’t observe dyson spheres because it’s less difficult instead to build vastly more efficient fusion reactors once you’re at that technology level.

“What if we took every animal on the planet and had them run on a treadmill…” or you could just build some fission reactors. about equivalent difficulty-to-ROI ratio.

likewise for this neuron discussion. still confused about the desire to explore carrying capacity, to explore the feasibility of having 12 billion humans let alone insane things like 1 trillion humans. what is the point of covering the planet with useless third worlders. really smart humans, who are actually useful, would never get to even 3 or 4 billion humans, so it’s a non-issue. and, they’ll step beyond neurons, once they get to that tech level.

24. Toronto Russian says

Do you mean phenotypic breeders? There could be multiple genotypes leading to the same phenotype.

Eg, Amish and Mormon.

It’s not like this. The Amish don’t reproduce like alguae in a pond just because it’s their nature. Demographer Lyman Stone found their reproduction appears to be calculated (they can do child spacing) and following the general US trends.

At least in the Geauga, Ohio Amish settlements, the decline in fertility followed national fertility trends very closely. Here’s a fun fact: the Amish don’t use most forms of birth control or abortion.

Now, this doesn’t mean Amish fertility fell as low as U.S. general fertility; it simply means that Amish fertility fell as much as U.S. general fertility.

In the modern period, we can see that, from the early 1980s to 2000, Amish fertility had actually fallen way more than U.S. TFR on the whole. Then it spiked in the late 2000s, and has fallen since.

But let’s zoom in on the 2000s for a second and index both Amish fertility and U.S. TFR to 2001.

You seein’ what I’m seein’? Cuz what I’m seein’ is that Amish fertility is pretty well correlated with U.S. TFR on the whole. And no, the Amish are not a big enough population to drive this trend: removing the Amish from the sample doesn’t change U.S. TFR essentially at all.

So this is actually very important. See, the Amish are cut off from certain parts of U.S. society (many cultural norms, certain technologies, etc), but they aren’t cut off from others. The Amish have farms and businesses that have to make money, and most Amish consider it morally acceptable to manage the spacing (and to a limited extent even the total number) of childbirths. So the Amish are impacted by the business cycle.

I have been strongly on the side saying that the decline in fertility in the U.S. is driven by technological changes (LARCs and emergency contraception) and by cultural changes; that the business cycle is not the primary cause anymore.

But the evidence from the Amish suggests otherwise. Even a group that had contraceptive use and cultural norms held roughly constant experienced a similar change in fertility as the U.S. general population. The only thing that they would have been exposed to is economically-transmitted fertility shocks via changes in economic returns from their businesses which sell to non-Amish people. This biases in favor of economic cyclicality driving fertility trends, and against culture.

https://medium.com/migration-issues/how-long-until-were-all-amish-268e3d0de87

And the Mormon TFR fell under 3. All these fertility discussions made me quite convinced that fertility is like fashion – it’s influenced by your peers, not your parents (‘ genes). Women have X kids because other women around them have X kids.

25. Paul Yarbles says

A bunch of mostly atheist near-zero-TFR white male nerds …

… a bit of moral authority among atheist white male nerds.

It’s OK to be an Atheistic White Male Nerd.