The Fermi Paradox, Percolation, and Inbreeding
reactormag.com
reactormag.com
Looking at the chart of "Each colony hop has 90% the "diversity" of its parent", we see that by the 10th we only have 34% diversity left.
It's not at all clear that 34% of diversity is too small. On earth right now, we had smaller groups of people arrive at some general location and tend to mostly reproduce within that group, creating what we now call "ethnic groups". Is 34% diversity more or less diversity than currently exists in, say, Ireland, or Norway?
Furthermore, the article completely ignores that over time spontaneous mutations contribute new genetic diversity. It doesn't give a time scale for the "send a ship, wait for the colony to grow large enough to colonize a new world" iteration but I would imagine that in the time it takes that to happen 10 times sequentially you will have more than enough new genetic diversity.
Makes me wonder if a solar system wide civilization, with trillions of beings, wouldn't invest in ships to go to the next system, extract resources, and create a stream of resources ships going back to the original solar system.
That might sound uneconomical. Why not just go to the other system? But moving trillions of beings, and disrupting all their practical considerations and dependencies, would be a far more costly enterprise.
In the short run it would be resource acquisition. In the long run, the new system would accumulate entities, and then a civilization of its own. But there might still be strong value, or incentives, for the original system to continue acting as a kind of capital/dominant/higher value location.
Long distance/time dependencies could develop and be naturally maintained via complex decentralized indirect but intertwined economic arrangements. Just as shareholders who have done nothing but push a button on their phone to get an electronic record of having some stock in a company, have strong property rights over complex systems they may never see or understand, because it is in everyone's interest for the system to keep working.
Also, automated systems that defend themselves and their owners positions, even across a few light years. With the owners being able to trade their value in real time, even if the physical returns are long term.
This reminds me of those old 4X-type games like "Stars!" where I would often do exactly this. Basically some planets were good for living on and others were good for mining and you'd have a constant caravan of freighters from the latter to the former.
But that would require causality-breaking FTL, no? Otherwise the speed of light itself would create enough of an obstacle to make any trade impractical. Property rights only work if they are enforceable, which is the case on Earth but not over interstellar distances.
And when there is reliability, even over vast distances and time, that future-value can be traded as today-value. With risk assessments of course, but this is how a great deal of the economy works. More and more of the economy, as it becomes growth and innovation focused, operates on the currency of expectation.
You mean colonize and feed the empire?
An odd assumption if we’re generously granting FTL or even regular space travel to aliens.
Everything from the lack of radio communication to the commonness of biological precursors like nucleic acids and amino acids in space points to multicellularity being the relatively rare thing, at least in our part of the galaxy.
We don’t hear from them or see them because if they’re out there, they’re still microbes eating each other. That one case of the two forming a symbiotic relationship, which leads to more endosymbiosis… that’s where I suspect our real rareness lies.
If you look at the (im)practicalities of interstellar travel, it's going to take centuries. That means a generational ship of some kind. That means having a sufficient population to get there, which really means tens of thousands of people. Plus, the kind of ship that would make that would likely host up to millions. That's just not going to create a genetic bottleneck.
Also, you could even mitigate that by bringing frozen genetic material.
Common trope in sci-fi, pretty much impossible in practise. Humans aren't capable of surviving being frozen, we lack the genetic machinery for that. Could you breed/engineer hybernation-capable humans? Sure. Otherwise this approach would require to literally being able to kill and then resurrect people at will.
> Or have a robot ship that gives birth to the colonists from an artificial womb on arrival.
I like this idea. It kills two birds with one stone: for one, fertilized eggs and fetuses can be stored safely for a long time.
Secondly - and I think this is something that's underdiscussed - genetic modification will be necessary anyway. The target environment won't be a carbon copy of Earth. Different atmosphere, different gravity, different starlight, different pathogens, etc. If you insist on colonising planets and start terraforming via automated means ahead of time, the resulting ecosphere will still differ from Earth and adjustments will be necessary. A ship carrying unborn settlers would be informed of the specifics of the target world and the ship's biolabs could make genetic alterations accordingly.
Even generational ships are a challenge, but more important, if we are able to make long term self-sustaining generational ships maybe we won't need to land, or change the equation between traveling and settling.
In any case, we didn't reach any outer solar system planet yet, not even with probes. We might not be fully aware of many of the practical problems of reaching and settling on another solar system planet. We might be like ancient mesopothamians asking ourselves why we shouldn't be able to build a tower to the moon.
Essentially, we've been humans for about 200,000 years. But only in the last 5,000ish years have we done the whole civilization thing. Why?
Climate has a lot to do with it, we know that, but about 195,000 years is a lot of time too.
Quite the mystery.
Even just 2G would require much more advanced technology than we have now to escape the planet
I think this is where it all went wrong. Overly optimistic assumptions from atomic age thinkers about how technology was going to overcome all obstacles in the near future based on their recent life experience. The thinkers seriously underestimated the amount of technological progress needed to produce an extremely complex machine that operates indefinitely with no outside support whatsoever in an environment where any error can be fatal and there is a constant stream of hazards to contend with.
You might be thinking: "So what, it just means it takes a few centuries longer to get started, in Geological terms that is nothing.", but the problem isn't that it is hard, it is that it makes the trip significantly harder than simply building orbital habitats in your home solar system. Once you have that, what is the point of spending vast amounts of resources in trying to colonize a mostly unknown star system tens or hundreds of light years away?
Sure there are always people who will want to climb Everest, but this problem is so big that it's unlikely that one person or even a small group will be able to undertake it. The resource investment is simply too colossal. It would be much harder to climb Everest if you had to convince the entire population of London to come with you.
Speciation is a likely outcome for interplanetary and interstellar colonies, yes.
First, it assumes that lack of genetic diversity in humans would be a serious handicap, when we're considering humans that are capable of making interstellar journeys. Assuming that genetics are going to be an issue compared to traveling/surviving 7 or more light year-journeys is a leap.
Second, it assumes that if this were a problem, humans would/could think of no way to address it. Two solutions come immediately to mind: 1. Choose the people making the journey more carefully to ensure diversity 2. Send frozen embryos chosen for diversity along.
Third, it ignores the time scale over which something like this would be likely to happen. Of course, you can't guarantee that beneficial diversity will re-occur, even over centuries, but a little effort on the front end combined with the time it would take to continue on to the next hop seems hopeful.
Fourth, it ignores the possibility of repeat journeys. If we're really going to constrain the available destinations in the way presented, it's silly to propose that there will be just one colonizing event.
But really, the first solution is all you need. The idea that we'll be able to survive multiple generations in space but not handle genetics issues is, just, a real stretch.
The reasons may or may not be something we could comprehend, but they could be simple ideas like
1. Not being motivated by novelty
2. Not wanting to interfere with other life
3. Being completely inward-focused
Humans will have also evolved into new kinds of immortal/superintelligent beings that would be totally unrecognizable to us.
It may be the case once a civilization reaches "max level" they universally decide to "reset the game" because there's nothing left to do. Maybe self-destruction or maybe they "spawn" a new universe. The possibilities are wild.
There’s no reason beyond wishful thinking to believe any of that is true.
We've only been in "technological takeoff" for ~250 years and are already using spaceships and computers to deliver and operate drones on Mars.
Now imagine 250 years + 1,000,000 years.
Even if 99.99% of people died from an asteroid, it might only take a few hundred (or thousand) years to rebuild the population and the world.
And once humans live on multiple planets, which is likely within 100 years, the odds of permanent extinction become remote.
It's not just that we need to have people living on another planet, we need a fully self-sufficient civilization on another planet which is at least 200+ years of sustained effort probably more because it took that long under the relatively ideal and easy conditions of simply settling another continent. Then factor in that their civilization would be even more precarious than ours and face many more dangers.
Life is still likely (not guaranteed) to escape Earth one way or another, however long it takes and however many attempts it takes.
Your statement that progress or intelligence is binary has no basis outside of intentional and ignorant pessimism.
In what basis do you presume our progress will continue exponentially?
I’ll take pessimism over wishful thinking.
We know how much ice is on land, people have spent decades drilling the ice and calculating it's volume etc, we know it's melting because there's way less of it now than there was just decades ago and we know how much that melted ice will influence water levels.
We know the effect greenhouse gases have on the atmosphere and global temperatures, people have made scientifically informed charts predicting how the temperature will rise decades ago and we are right on track.
The prediction happened when I was a child, and all my life I've watched the prediction come true. The fact that there's still millions if not billions of people out there who are living through the same situation and still think climate change is a hoax is absolutely baffling to me. Just look at a fucking global average temperature chart for the past few decades holy shit man it's not a secret the planet is cooking. It's not maybe going to cook 500 years from now it's cooking right now and it's getting worse every year how can you possibly look at these simple clear facts and not understand that it's going to continue?
You guys annoy me so much holy shit open your eyes and just look at the world we live in
You're not using "science" to predict the future. You're just expressing a pessimistic belief that we're doomed based your own idea of how things will play out.
To me, optimism seems far more justified based on our track record, we've more-or-less solved some big problems:
- "Population growth is going to cause worldwide famine"
- "We are going to run out of oil and civilization will collapse"
- "The ozone hole is going to expose everyone to dangerous radiation"
- "Acid rain is going to destroy forests and kill lakes"
- "City air pollution is going to make major cities unlivable"
- and smallpox/polio/HIV/leaded gasoline/etc
Climate change is not solvable. There is no solution. The only thing I know of that we might be able to do is spray enormous amounts of aerosols into the atmosphere hoping to block the sunlight. This might backfire spectacularly, also might not even work. It's a hail Mary we'll probably try when things get bad enough.
That's it. That's the only idea we have that might help. Maybe there's others I don't know about, but they're not good or we would be doing them already. Carbon capture is a joke, it will never make a difference. We would need a million carbon capture plants, we can't build a million capture plants.
Even if we completely stopped emitting CO2 today we would be completely fucked, and we're not doing that we are in fact producing more CO2 every year. That will probably change eventually but it's already too late.
Obviously nobody can know for sure, maybe we will get lucky and someone will come up with a genius plan that actually works. But that's far from guaranteed, as far as we know right now it's impossible so just assuming that's going to change is extremely naive. It's a thin sliver of hope it's not what we should be expecting nor relying on.
We have no good solution, and given the scale of the problem we have almost no hope of finding one. Do you understand how much atmosphere there is? We've been burning fossil fuels as fast as we can for centuries, now we are finally seeing the result of that and it's so slow that lots of people still don't believe it's happening. It's way harder to reverse.
Also, ice. Ice is important. Ice reflects sunlight and essentially stores cold. Less ice means more heat. More heat means less ice. Do you understand how long it's taken to build the amount of ice on the planet? Absolutely no amount of terraforming will rebuild the ice we're losing and have lost, not in thousands of years.
This is a claim about the future which the science does not support, and you seem to be basing a lot of your worldview on it. Have some humility about predicting the future.
> Obviously nobody can know for sure, maybe we will get lucky and someone will come up with a genius plan that actually works.
Nobody can know at all. We're talking about predicting the future.
But it's not really a matter of luck. Humans are problem solvers, now with immense power, capable of doing amazing things when we decide to.
There is scientific consensus that +5C is a doomsday scenario. Civilization ending. This isn't my prediction, this is the scientific consensus. And obviously it's not like +3C or +4C is a walk in the park either. We will be close to +5C within this century unless something changes drastically.
That's not a prediction that's a projection, just like if you're driving your car at 100 miles per hour then in an hour you will be 100 miles ahead. The difference is when it comes to greenhouse gas emissions we do not have a brake pedal and there is no friction. We can't take back the carbon. The only thing we can do, and the only thing we are doing, is accelerate. And on top of that, we're going downhill - we're accelerating whether we want to or not. And it's getting steeper the further we go.
Ice reflects an enormous amount of energy back into space, as the amount of ice drops the amount of heat absorbed by the planet increases. On top of that, the ice traps enormous amounts of greenhouse gases. In the poles and previously permafrozen tundras that are now thawing. As the atmosphere heats up it is capable of holding more water vapor which is also a greenhouse gas. Warmer temperatures also lead to forest fires, releasing huge amounts of greenhouse gases and weakening one of the few ways we're actually removing some carbon from the air.
These are some of the feedback loops in play causing warming to rise exponentially the worse it gets.
> Nobody can know at all. We're talking about predicting the future.
Scientists predicted the future 50 years ago and we are right on track for those predictions. 50 years ago they said this is where we will be in 50 years, and here we are. Now you're like "but we can't predict the future" well we did. And to top if off you're waxing about how powerful we are - apparently not powerful enough to predict global warming, but powerful enough to stop it? When? Why aren't we doing it then if we're so powerful? Why are we just making it worse instead?
Not sure what your definition of "cohesive" is but we've had our civilization going for ~5000 years with only regional setbacks.
1. The population size in the colony will be very small. Maybe? It should be at least MVP (minimum viable population, not product) that is a relatively well researched concept. I'd argue that it won't be a colony below that. More of an outpost. And when talking about aliens and Fermi paradox, we don't even know what their MVP might be. It may not be even close to MVP of vertebrates on Earth.
2. That selecting the colonists by some criteria is not useful. It is, it's just not selecting by the "best genes". It's selecting for more diversity in the first place. Lack of diversity in the colony is much less of a problem, if more of it is introduced in the first place.
3. That colonization is an isolated thing and people won't arrive/leave over time. Why wouldn't there be more than one colony ship, if sending them becomes viable overall?
4. The population does not grow and remains at the original diversity levels. Combined with 2 and 3, it may not even matter that much. Unless it experiences a series of catastrophes, it should keep growing and becoming more diverse over time again. This is of course the most questionable case. Will it? I think considering how humanity has spread like a plague on Earth, it won't be a problem.
Almost stopped reading after that one (I groaned, it's still to early!) but feel that's when the article kind of lost its plot. Worth reading though some good nuggets here.
I am firmly convinced the observable universe is just too exceedingly vast for intelligent life to sustain contact. Maybe i'm wrong!
I wish there was more background on Percolation Theory because that's not something I'd been exposed to before. But after looking into it more it am happy I did: [0]
As a kid sitting in the backseat of the car (or adult driving looking through a windshield) I always noticed how raindrops would hit the glass, then continue to coalesce with other drops and form larger drops before flying off the pane. Is it the same thing?
Fermi's contention of "where are they?" was predicated on two things 1) the probability that intelligent life exists elsewhere in the galaxy and 2) that faster than light travel is possible and would be discovered by a technological society.
The napkin math that Fermi did was essentially what we now know as the Drake equation. One important variable in this is the duration of a technological civilization. I personally believe that Fermi would assign the probability of a civilization existing for "geological timescales" necessary to colonize the galaxy using slower than light travel at zero which is a clear resolution to this Not-Fermi Paradox. His paradox is only so because he thought FTL would be discovered in the not very distant future which makes the duration required for a technological civilization quite small and allows them to visit many worlds quickly, with or without a galactic empire which in this interpretation could realistically exist for a normal timescale and not the frankly ridiculous millions of years that the Not-Fermi Paradox always seems to take for granted.
tldr; if it doesn't involve FTL it's not the Fermi Paradox, choose a different name
First, I would just naturally assume you are wrong as Fermi would have known that FTL was practically impossible.
Fermi evidently made the comment in the 1950s at Los Alamos, as I understand it became widely known due to Carl Sagan's 1963 paper "Direct contact among galactic civilizations by relativistic interstellar spaceflight"
https://www.sciencedirect.com/science/article/abs/pii/003206...
What the Fermi paradox involves is near light speeds, because, as Sagan says in the paper above "Interstellar spaceflight at relativistic velocities has several obvious advantages... all points in the Galaxy are accessible within the lifetime of a human crew, due to relativistic time dilation."
There is also the Michael Hart paper "Explanation for the Absence of Extraterrestrials on Earth" from 1975 but I have not found any satisfactory for open reading source of this online.
At any rate it seems absurd that any famous physicist of the last 90 years at least would ever have suggested that aliens should have been here because they would have had faster than light travel. You are essentially saying Fermi thought Einstein's Theory of Relativity was very much wrong.
on edit: I said 90 years to hedge bets in case there was some really old guy still hanging around in 1935, science progressing one funeral at a time and all that. But it seems really unlikely that there would have been.
"York believes that Fermi was somewhat more expansive and 1‘followed up with a series of calculations on the probability of earthlike planets, the probability of life given an earth, the probability of humans given life, the likely rise and duration of high technology, and so on. He concluded on the basis of such calculations that we ought to have been visited long ago and many times over. As 1 recall, he went on to conclude that the reason we hadn’t been visited might be that interstellar flight is impossible, or, if it is possible, always judged to be not worth the effort, or technological civilization doesn’t last long enough for it to happen. ” York confessed to being hazy about these last remarks."[0]
The recollection of the conversation by all the parties present is fragmentary and disagrees on exactly what was discussed but the gist of it appears to be about the feasibility of interstellar travel, not colonization or percolation or whatever you want to call it. The whole question of "where are they" doesn't make much sense when you think of it in terms of one off events such as permanent settlement of a planet using generation ships or other feasible means of slower than light travel simply because you would always miss each other in time. Either we wouldn't be here because they settled Earth first and interrupted our development or they're not going to show up for another million years.
I'm not contending that Fermi necessarily believed that the theory of relativity was wrong or incomplete but that the essence of the Fermi Paradox is that either interstellar travel is impossible due to distance + time required or there is some way to overcome the restrictions of distance + time which during this informal discussion over lunch seems to have supposed faster than light travel as the solution. Based on the recollected pieces of the conversation I'm pretty sure Fermi's napkin math didn't involve fudging the likely duration of a technological civilization up to millions of years, the likelihood of that happening is certainly less than Einstein's theory being incomplete.
Honestly, the argument as it is proposed today should be attributed to Hart since it conforms exactly with what he proposes so from now on I'm going to call this form the Hart Paradox.
[0] https://upload.wikimedia.org/wikipedia/commons/5/54/%22Where...
So I feel it is really Sagan's summation of the problem that is the original. So I would say maybe they said the only way it could work was if there was FTL or some similar formulation, but I think Sagan also showed that it could work in other ways.
So I guess we just sort of disagree on this.
Inventions of language and writing are the landmark moment here. Before language was invented the only way information could be passed down from ancestors to offspring was via mutations in our DNA. If an individual learned some new idea it would be lost with them when they died. Language allowed humans to communicate ideas to future generations and start accumulating knowledge beyond what a single individual could hold in their head. Writing made this process even more efficient.
So, after millions of years of life on Earth no technological development happened. Then when language was invented humans started creating technology, and in a blink of an eye on cosmological scale we went from living in caves to visiting space in our rocket ships. It’s worth taking a moment to really appreciate just how fast our technology evolved once we were able to start accumulating knowledge using language and writing.
Now let’s take a look at how technology itself has been evolving. Once we discovered radio communication we went through a noisy period where we were leaking a lot of our broadcasts into space, and within a span of a 100 years we started using more efficient communication, and encryption. If somebody intercepted our broadcasts today they would look like noise because they’re designed to look like noise. Our society today is utterly and completely unrecognizable to somebody from even a 100 years ago. If we don’t go extinct, I imagine that in another thousand years future humans will be completely alien to us as well.
So the period during which intelligent life would be recognizable to us during its course of evolution is infinitesimally small. The time between creating language and becoming an advanced technological society is measured in thousands of years, while evolution of life is measured in millions of years. The chance of two different intelligences finding each other at exact same stage of development where they might be able to communicate is incredibly unlikely.
Based on that, I would imagine that the biological phase for intelligent life is rather short. We’re likely to develop human style AIs within a century, and they will be the ones to go out and explore the universe. Meat did not evolve to live in space, we’re adapted to gravity wells. An artificial life form could be engineered to thrive in space without ever needing to visit planets. This is the kind of life that’s most likely to be prolific in space. Furthermore, post biological intelligences would likely be running at much faster speeds than our mental processes operate on. What we consider real-time would be might we consider to be geological scales. Such beings might consider what we view as real time akin to the way we look at continental drift. We’re aware that it’s happening, but it’s of little interest to use on day to day basis. It’s quite possible that advanced civilizations become solipsistic and care little for the outside universe.
For all we know the Universe may be teeming with intelligent life and we just don’t recognize it as such. We might be like an ant hill next to a highway looking to see if there are other ant hills around.
Language (in the sense of "use of language appears around 100,000 years ago") is not the only way to communicate information, and many animal species are perfectly capable of communicating information despite not having evolved what is being called "language" in this sense.
In general, pre-writing human oral culture seems to have dynamics much in common with such abilities in other animals. Barring error correction mechanisms, oral knowledge can degrade in transmission, limiting its reach and success.
This isn’t to say human language doesn’t have its distinctive features that are very useful. But the language came from a different brain, and is suited to the particularity of our brains. We should hesitate to place solely on language something that’s also driven by us having more things to say.
The language itself is a a human invention, and a product of how our brains are wired. However, there's a dialectical process here where the language shapes us in turn, and both our minds and our language evolve together. The reason we have more things to say stems from us accumulating knowledge and expanding out horizons through the use of our language.
Instead, these co-evolved. Our language is shaped by that, and we shouldn’t give it too much causal power when it’s only a slice of the system.
We are also very unclear on what birds can communicate. They’re social migratory species with 4 color vision and magnetoreception. Their sensory context is deeper and richer in some ways, and whatever communication they layer atop it will be shaped by that. What seems like squeaks and chirps can hold information that another bird, but not humans, can decode. We’re getting better at layering all this context and then interpreting bird song and sounds.
But we’re at the beginning of this exercise, not a place where we can make a firm conclusion.
What we can look at is what other species are able to accomplish and how much they are able to shape their environment. I'm not arguing the fact that we don't have a good grasp on how other animal communicate and different kinds of intelligence we have in the animal kingdom. What I'm saying is that our unique combination of being able to abstract concepts and package them up using language, and especially writing, is what allowed up to rapidly accumulate knowledge and pass it across generations. We are demonstrably the only species that does this. Although, there were other hominids originally with similar capabilities that went extinct.
You speak of “prerequisite brain structures to support recursive grammars”… would they arise in short lived species, given we know these are complex brain regions that take time to develop, need experience to become fully useful, and are energetically expensive to maintain and run? How do you do that if you live a relatively short time?
On the flip side, precisely in longer lived species like whales and elephants, your statements begin to fail. Elephants (when left in the wild) do accumulate knowledge of huge stretches of a continent and pass on that knowledge horizontally and also down to their progeny.
Whales and dolphins also show initial signs of such linguistic competence.
What these species don’t have is our opposable thumbs, etc. Things that aren’t directly responsible for language and would have evolved without it (as opposable thumbs have in other species), that nevertheless added to what language can do.
That should give you a sense of how language in humans is only as complex as the humans and their society is.
As for writing, I’m really not clear that it’s better than leaving smell traces, when it comes to information density, and speed of sharing. Where it does better is in surviving across generations, and that is indeed an advantage, that our language can go through a short lived medium (sound) AND a longer lived medium which doesn’t tax our memories as much.
Note that writing is a much later invention though, than language. And very tied to our opposable thumbs which can make fine marks and do so repeatably enough that we could associate repeated sounds with repeatable symbols and generate this writing based transmission system. Take that away and we’d remain an oral culture. We’d have do what Sanskrit users did before they found stable ways to write, and create ways to improve memorization. That too has survived generations. Just takes a lot more of each person learning, compared to writing.
This is my preferred answer to the Fermi question as well. Unless two civilisations are in a precise (and likely small) window where they both can and want to communicate, it's likely the less advanced one wouldn't even recognise the other one. Especially if the other one doesn't "want" to be recognised.