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Robin Hanson on Grabby Aliens and When Humanity Will Meet Them
336 Plays2 years ago
Robin Hanson joins the podcast to explain his theory of grabby aliens and its implications for the future of humanity.
Learn more about the theory here: https://grabbyaliens.com
Timestamps:
00:00 Introduction
00:49 Why should we care about aliens?
05:58 Loud alien civilizations and quiet alien civilizations
08:16 Why would some alien civilizations be quiet?
14:50 The moving parts of the grabby aliens model
23:57 Why is humanity early in the universe?
28:46 Could't we just be alone in the universe?
33:15 When will humanity expand into space?
46:05 Will humanity be more advanced than the aliens we meet?
49:32 What if we discovered aliens tomorrow?
53:44 Should the way we think about aliens change our actions?
57:48 Can we reasonably theorize about aliens?
53:39 The next episode
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Transcript
Introduction to Gus Dogger and Robin Hanson
00:00:00
Speaker
Welcome to the Future of Life Institute podcast. My name is Gus Dogger. On this episode, I talk with Robin Hansen. Robin is an economist at George Mason University, but even though Robin is an economist by title, he's published in a wide number of fields ranging from psychology to astrophysics.
Exploring the 'Grabby Aliens' Theory
00:00:22
Speaker
On this episode, we talk about Robin's theory of grabby aliens. This is a new model that attempts to explain whether there are aliens in the universe and where they might be. We discuss how the model works and what it might tell us about the future of humanity. Here is Robin Hanson. Robin, thanks for being with us.
00:00:46
Speaker
Nice to see you again. Fantastic. All right. Let's talk a bit about aliens. And I think the first question we should cover here is, why do you care about aliens? Why have you published papers on aliens? Isn't this simply too far out to try to research?
00:01:09
Speaker
My general intellectual strategy has been look for important neglected questions where I can find some original angle where I could do something new other people hadn't done. So the topic of aliens just seems obviously important.
Academia's Overlooked Questions
00:01:26
Speaker
And when I first started reading about it, I had no particular expectation that I could have any original contribution because of course it was of such interest to so many people, how could I?
00:01:37
Speaker
But what I've learned is that in fact, academia clumps quite badly and it just neglects a lot of big important things. And so I've often had substantial success just finding a thing that seems obviously big and important that academics tend to shy away from and just diving in.
00:01:57
Speaker
maybe those topics that seem obviously important to you do not seem obviously important to other academics. Maybe that's the most straightforward explanation there.
Significance of Cosmology and Alien Influence
00:02:08
Speaker
I don't think so. That is, I think if you just ask ordinary people what topics are important, there is an awful lot of agreement. And I tend to agree with ordinary people's rough assessment of things. And certainly here, we're just talking about the largest history across space and time. We're just talking about the overall cosmology, basically. So clearly, a lot of people think cosmology is important.
00:02:31
Speaker
Where did the universe come from? Where is it going? And this is just a big thing that matters for cosmology. If the universe will fill up with advanced aliens, then the universe from then on will be determined by them, not by, you know, dead matter star evolution processes.
00:02:46
Speaker
So we often imagine that we can look into the very far future of the universe and predict how galaxies will move and predict how stars will spread apart and so on. But maybe this ignores the possibility of aliens doing engineering on enormous scale and moving stuff around in the universe that actually changes things on such a big scale level.
Predicting the Future and Adaptive Strategies
00:03:16
Speaker
A lot of people just have a mental block about our future in terms of its big technological potential. That is, it just scares them or it seems just too much or not something they should do. In fact, many people sort of invoke a simple methodological principle of it's impossible to predict the future. And then they just declare that the future is off limits because it's impossible to say anything about.
00:03:43
Speaker
And then they go on with imagining nothing will happen in the future because that's the simplest thing they think. So just assume the future is like the past and make and take into account nothing you know about what's happening lately and how we're changing things.
00:03:57
Speaker
Could this be kind of a heuristic that people have developed because it's just so damn hard to predict what's happening, what will happen in the future? And so it's better in some cases not to try and maybe that translates into a thought that we can't predict the future at all. I don't buy that so much, but I do think that in fact there's often a planning fallacy or that people often over plan.
00:04:25
Speaker
And instead of planning, they should just prepare to adapt. And that's in fact, a reasonable attitude toward many kinds of over planning in our world. So for example,
00:04:36
Speaker
If you look at like billion dollar projects in the world, they just tend to go very badly. Most billion dollar projects are just done way over budget, way over time, don't work that well. And apparently people just delude themselves into thinking they are able to do billion dollar projects. And often it's some sort of political or organizational pride thing where they're going to make a name for themselves and be the toast of the world because they do this big grant project.
00:05:02
Speaker
And it's just hard to do long projects. So I certainly think there's a reasonable place for caution there. But I don't think that means you should go all the way toward we have no idea what might happen in the future.
00:05:14
Speaker
Yeah, and aliens really, thinking about aliens is really one of the biggest things we could think about. Maybe a highly advanced AI is up there, but I can't really think of anything other in that category. Aliens could really, really, if they exist, affect our future and the future of the universe. So it's a massive topic to think about.
00:05:39
Speaker
It's not just the future, it's also the past.
Impact of Advanced Aliens on Space-Time
00:05:41
Speaker
That is, you just look out into all of space-time. One of the biggest things that might make a difference out there in space-time is advanced aliens. I mean, they can just change a lot. So if you're interested at all on large scales of space-time, it's just an obvious question that has to occur to you.
00:05:58
Speaker
All right, let's get into the meat of your theory here.
Loud vs. Quiet Alien Civilizations
00:06:02
Speaker
You have two types of alien civilizations, loud civilizations and quiet civilizations. What's the difference there? Well, the difference is we ought to be able to see the loud ones and hear them. So we look out in the universe and we don't see very much. And that doesn't say much about the quiet ones. That is, the quiet ones that would be small and quiet and not last for long and not do very much.
00:06:27
Speaker
but you know we have a limited ability to see in here so our limited ability to see in here is really quite consistent with a wide range of quiet aliens but big loud aliens that we might be able to see so
00:06:41
Speaker
It makes sense to at least take our basic data that we have right now of what we can see and what we can't see and confront that with the theory of loud aliens. That is, we should be able to take a space of possible theories of loud aliens and eliminate some of the theories from consideration by comparing what we see with what those theories would predict.
00:07:01
Speaker
So a quiet civilization would be a civilization like humanity is now. So it's not that that we aren't doing anything, but we're not changing our solar system or a galaxy in a way that's visible from very, very far away. Right. I mean, the motive is that we do think it's plausible that in our future we might become very loud. That is
00:07:24
Speaker
Not only might we say change the sun in terms of its color spectrum a little bit, we might take apart the sun. We might go to the nearest thousand suns and take them all apart. We might go to the entire galaxy and take it apart and rearrange it and not just change the color spectrum a tiny bit, but change where the light comes from or whether it's light or where all the mass sits and what it's doing.
00:07:46
Speaker
We have some pretty ambitious plans for the future. Now, they don't happen immediately. That is, it might take 10 million years to achieve these visions. But 10 million years is a tiny time on cosmological scales. It makes almost no difference. So if you ask, what might we do in 10 million years? We think there's at least a small chance we could do some really big things. And then we can focus attention on aliens who might be doing those really big things.
00:08:16
Speaker
Why would some alien civilizations be quiet?
Quiet Civilizations and Expansion Limits
00:08:20
Speaker
Well, we are quiet now, and so they might not make the transition to loud. Obviously, one way they might just die, or they might freeze themselves into some limited form that can't grow or refuses to grow.
00:08:37
Speaker
Or they might choose not to expand. So I actually think that'll be the biggest choice our descendants will probably make, is to decide whether or not to allow themselves to expand out into the universe. Because once you think about it, there's a lot of downsides to that. Such as? Well, in the last century or so, we have been
00:09:01
Speaker
becoming together as a world community in many ways. And I'm amazed that we weren't for the previous 10,000 years. Fourth 10,000 years ago, we most lived in small forager groups of maybe 30 people. And in those small groups, we didn't actually fight that much. We didn't do wars. We had some maybe sexual jealousy violence, but mostly we decided things together. We sat around the campfire and made key decisions about who to punish for what or when to move to another place.
00:09:28
Speaker
We're mostly on friendly terms with our natives. And in the last 10,000 years, we lost that. We moved into a world where we have wars with each other and we're competing and fighting across the globe. But in the last century, we've been slowly drifting back more toward a world community where world elites at least talk around the world. And when a big thing like COVID happens, they all talk together about what to do and they agree then what to do and then they all do it pretty much.
00:09:54
Speaker
So humanity has been moving closer together and so your worry here would be that if we spread into the universe we would once again move further apart and become less
World Governance and Universe Expansion
00:10:07
Speaker
able to communicate. We've been enjoying the fact that instead of
00:10:11
Speaker
competing via war and fierce business competition, we have agreed at a global level how to limit war, we've agreed on how to regulate many kinds of business and other activities, and we like this world where we all decide together on major things and we'll slowly over the next centuries even have more world governance.
00:10:32
Speaker
where we impose rules more on everyone to follow the rules. And one of the things that we like about this is that we will prevent out of control evolution of our descendants. That is whenever people have talked about genetic engineering or other kinds of
00:10:49
Speaker
AI, even engineering, many people don't like these images. They are scared of them and they think they're dangerous. And they want to have some sort of collective control over these things to limit and manage how our descendants might become different from us. And that's all possible within a solar system, say, that is, you know,
00:11:12
Speaker
advanced and full of technology and people, but even a solar system is close enough together that if one part of it wants to violate the rules, other parts of it can smash them and make them follow the rules. But once we allow any descendants to leave the solar system and start creating colonies on other stars and many thousands of stars,
00:11:37
Speaker
At that point, it's no longer possible to have a civilization-wide governance, a civilization-wide conversation where we agree together on what to do and then make us all do it. And it's not possible then to prevent our descendants evolving to become strange things. Not only strange things that violate our norms, but that come back here to contest for control with us over this place. That's a consequence of allowing interstellar colonization.
00:12:03
Speaker
This would push us to stay quiet as a civilization and it may have pushed alien civilizations to stay quiet. I'm thinking that when scientists have speculated about the existence of aliens traditionally, maybe they've assumed that aliens are quiet
00:12:23
Speaker
They've assumed that, well, we have no evidence. We can't see any aliens, so we have to go back to reasoning from first principles. And they've been using what's called the Drake equation to do this, which is thinking about basically proportions of planets that could be habitable, and then getting smaller and smaller percentages of planets that could house aliens, and then thinking,
00:12:53
Speaker
Thinking in terms of this equation about how many aliens there would be, do you think we've traditionally assumed that aliens would be quiet? I think that's been a dominant assumption in the world. Now, a long time ago, some people in this space in astrophysics reasoning about agents did consider the possibility that aliens would expand enormously and have an enormous impact on the universe.
00:13:19
Speaker
And I think a lot of people just were repelled by that vision. And it sort of conflicted with their politics even.
00:13:27
Speaker
And a lot of people have sort of expressed the axiom that advanced aliens would have to be peaceful and not aggressive because otherwise they would have destroyed themselves. And so the vision that they had for our future is the vision that they insisted would be the only feasible vision for aliens. And that would be a way that they could tell other people today that we should follow their vision because otherwise we will die.
00:13:53
Speaker
And so they had a political lesson about that. They were saying, look, the only way to be a long-lasting, successful alien civilization is to become peaceful and non-aggressive and ecologically aware, et cetera. And they wanted that message to go out to the world here today that that's what we should become. And that message would be affirmed by their claim that no aliens ever do otherwise, because if they do otherwise, they die.
00:14:21
Speaker
So thinking about loud aliens, expansive alien civilizations that expand and so on, maybe this line of thinking was rejected on irrational grounds? Well, political grounds. Political grounds. OK. But maybe the distinction there is not always perfectly clear. They had an agenda, a story they wanted to tell. And you can see how that could animate our descendants to choose not to allow expansion.
00:14:49
Speaker
Yeah, all right. But what you've been theorizing about is basically loud aliens.
Rapid Expansion by Grabby Aliens
00:14:56
Speaker
So let's dig into the moving parts of your model here. You call it grabby aliens. And this is just to say that grabby aliens expand into the universe, and they grab more and more bigger and bigger regions of the universe.
00:15:14
Speaker
One thing you claim is that loud aliens, they will make changes, planet sized changes to their regions, and they will expand fast. So why would we expect alien civilizations to expand fast?
00:15:31
Speaker
Well, our model has three parameters. So it's not a very complicated model. There's two parameters of when they appear in space and time. So we assume they appear at random places on the on the grand scale of things and that they appear in time according to a power law.
00:15:48
Speaker
which has a constant and a power in it. The constant just says an overall rate. And the power is in terms of a set of hard steps that have to be achieved in order to reach an advanced level like ours. And then they expand at some speed. So the key assumption is just they all expand at roughly the same speed.
00:16:06
Speaker
presumably some roughly maximum feasible, but we don't actually assume it's a fast speed. We conclude it's a fast speed from our data. So the space of model says it could be a slow speed. And then our data says, no, it can't be a slow speed. It must be a fast speed. Maybe you could explain why it must be a fast speed based on the data. So again, we have these three parameters and the key idea is that each of the three parameters is going to be fit to data.
00:16:34
Speaker
So our current date we're going to assume is a random sample from the dates at which advanced aliens appear because we may not become loud but if we do it'll be in the next 10 million years. So that means at our current date of 14 million years since the big band this is a random sample from the data which says
00:16:55
Speaker
The first datum is our current date. Our second datum is the history of life on Earth, which gives us a clue to how many hard steps happened in the history of life on Earth, roughly six. And therefore the time appearance function has a power of six. Things appear more and more rapidly as the sixth power of time.
00:17:14
Speaker
What are these hard steps? What is an example of a hard steps? Is it the evolution of life on Earth or multicellular organisms, something like this? So the idea is that life has to go through a sequence of stages where in each stage it's searching for the next stage. There's a vast space of possibilities it's searching and define the key arrangement that will allow the next stage.
00:17:40
Speaker
and that we don't really know what these stages are. We have a number of candidates for them, say photosynthesis, multicellularity, eukaryites, sexual selection, etc. But what we do see is that life appeared on Earth at a certain date.
00:17:57
Speaker
And we can then consider the very first step as happening before that date. And then we know that we've appeared at a certain date right now before life on Earth will no longer be possible. And the simple theory of statistics says that these two durations are samples from the same distribution of duration of step sizes. So the first one took roughly 400 million years, and now we have roughly a billion years remaining.
00:18:26
Speaker
And those two numbers are samples from the typical step duration size. And that's what lets us say there's probably roughly six steps, you know, three to nine or something like that, steps that happened during the history of earth so far. And so we don't need to know which steps they were. What we mainly need to know is how many of them there are. And we can get that from that first duration and this last duration.
00:18:51
Speaker
And then we think that alien civilizations will have to go through the same number of steps in order to reach a level in which they can expand into the universe. Right, because if there were different paths of evolution that had different numbers of steps, the one with the smallest number of steps would be the overwhelmingly more likely thing to happen. So the universe would mainly be filled of things that use the smallest number of feasible steps. So that's why we would assume that our number of steps is the smallest feasible.
00:19:20
Speaker
Okay. And let's try to get back to this question of why alien civilizations would expand fast. Right. So the third parameter is the speed of expansion. So now we can take the other two parameters and we can do stochastic simulations of this model where we model the universe, assuming the number of steps we have and the constant we have from our date. And then we can model different speeds of expansion and see what they would imply about
00:19:49
Speaker
universe. So if we assume that we are a random sample from the origin of an advanced civilization date, we can ask at a random time when an advanced civilization appears in these models, how many other civilizations can it see? We can just use the model and simulate it and calculate that. And what we find is that when they expand slowly,
00:20:14
Speaker
at the origin time of when a typical civilization appears, it can see many other alien civilizations in the sky. And what these are is enormous spheres in the sky that much larger than the full moon, where within that sphere, everything is substantially changed. That is, you're looking at a sphere of alien colonization, maybe billions of light years across, in which for billions of years, they have been changing this stuff. And our key prediction is they would have made it look different somehow.
00:20:44
Speaker
exactly how we don't know, but it seems pretty likely that it would look different. Just like on Earth today, when there's a forest or a savannah, it looks different than empty rock. And a city looks different than an empty savannah. That is, you know, life and civilization changes things. But so the reasoning is that if civilizations, alien civilizations, expanded slowly, then we would see them. Right.
00:21:14
Speaker
Therefore they can't be expanding slowly and we can calculate how fast they would need to be expanding such that we most likely wouldn't see them in the sky and that's maybe roughly half the speed of light. So if they're expanding half the speed of light then we don't expect to see them in the sky.
00:21:30
Speaker
anthropic reasoning involved here when we're thinking about ourselves as observers. We couldn't exist in a universe in which alien civilizations had spread out and basically expanded to fill all regions. Could you explain whether there's some anthropic reasoning involved here?
00:21:53
Speaker
So, I mean, if you could give a link in this podcast to our Grabby Aliens website where we have a simulation that you can watch of how a Grabby Alien civilization scenario plays out. Yeah, I've watched that. It's incredibly interesting to see. The key observation is that at a random time when one civilization is arriving, basically a lot of the rest of the universe is already full of alien civilizations.
00:22:19
Speaker
And so at the typical average time, then basically half of the universe is full of aliens. That is half of the volume of the universe at that moment is occupied by old and advanced alien civilizations. And so that prediction seems to be at odds with our looking out in the universe and seeing nothing, nothing at all, zero, empty. But there's a selection effect. That is, if there were an alien civilization in our view,
00:22:49
Speaker
it would be here now instead of us. And then it would have precluded us from being here, at least in a situation where we would see an empty universe. So, I mean, the simplest assumption is alien civilizations just prevent the evolution of other intelligences within the spheres of their control. They might allow some previous existing evolving planet to stay isolated, perhaps, but then it would be within a sphere of control of
00:23:18
Speaker
other you know of an advanced civilization nearby and that's not what we see. So we can definitely conclude we're not in the middle of a sphere of an advanced civilization and therefore they would be here now instead of us if we could see them and so that's the main reason we don't see them. The universe we see is empty because we are arriving right now and the only way we could be arriving right now is if our planet
00:23:47
Speaker
and solar system and near space were just left empty, not being changed by an advanced civilization, but waiting for some advanced civilization to appear. One of the conclusions you arrive at is that humanity has arrived very early in the history of the universe.
Humanity's Place in the Universe's Timeline
00:24:03
Speaker
Maybe you could give us some dates here, because it's, what is it, 13.7 billion years since the Big Bang, and how long do we expect the universe to exist for?
00:24:15
Speaker
So one theory you might say is, no, no, no, there are no other aliens in the universe. We are the only ones and it's all completely empty. And that's the simple explanation for why we don't see anyone. And we say, no, that's not quite right. If the universe were completely empty and would just wait for us to appear as long as it took, then we should expect to appear much later than we did. So
00:24:45
Speaker
The peak of star formation was about 4 billion years after the beginning of the universe. And then the peak of habitable star formation was perhaps three times later or something because at the very beginning of the universe, there were all these young stars exploding and that was pretty harsh for a nearby life. But over time, the rate at which these explosions happened was declining. And so there are all these planets that formed.
00:25:15
Speaker
about 4 billion years after the universe started, and then they have an enormous distribution of lifetimes. And the average star, and therefore the average planet around it, will last for 5 trillion years. And some of them will last for hundreds of trillions of years. The average will last for 5 trillion. We're on an unusually short-lived
00:25:37
Speaker
star, a short-lived planet therefore, which so far has only lasted five billion years and only has another one billion years left of habitability on our planet. So we are very early
00:25:51
Speaker
in this history of the universe. Now you might say, well, that's because only stars like us can support life. And that just doesn't seem right to us. That is seems that there must be just a wide range of different paths by which life could appear. And in particular, that ocean worlds, worlds full of water are a reasonable candidate for places where life could appear.
00:26:13
Speaker
And that even though small stars have some problems in terms of, say, tidal locking and flares, those really aren't problems for ocean worlds. And therefore, there are many stars with many planets who could, in fact, evolve life sometime in the next 100 trillion years. So this hard step model I talked about predicts that if life has to go through a bunch of hard steps that are all difficult to finally get to our level,
00:26:42
Speaker
The time at which that will happen, the probability of that happening goes as time to the power of the number of hard steps, say 6. And therefore, if you have a star that lasts a thousand times longer than our star, say 5 trillion versus 5 billion,
00:27:01
Speaker
then not only is there 1,000 times as much time for life to appear on that longer-lived star, the chance of it appearing will be toward the end raised to the power of six, say, which means 1,000 raised to the power of six, i.e. 10 to the 18th. That is, there's a 10 to the 18th larger chance that advance like us would appear late on a much longer-lived star than it having appeared on our planet.
00:27:32
Speaker
which is such a short-lived planet in such a short time. Can we say anything about the probability of us having arrived this early in the universe by chance? Well, the little story here is that we made an assumption in this model that we were just analyzing. We were assuming the universe would sit and wait empty until we appeared. And that's the assumption we suggest is wrong.
00:27:58
Speaker
That is, at the moment the universe is filling up with advanced aliens, and in a few billion years, it'll be awful. At which point, it'll be too late to show up. So there was a deadline. And the universe would not wait until five trillion years for advanced life to appear. And that's why we couldn't appear on a longer-lived star and planet five trillion years in the future. We had to appear now before the deadline. And that's why
00:28:26
Speaker
The reason you should believe there are aliens out there is the day on the clock. That is, that's the evidence. You are really early. And the plausible reason you are really early is that there was a deadline. And so that's why you know they're out there. They're out there right now, filling up the universe. You can't see them, but you know they're there because of the day on the clock. I'm not totally sure I'm following this.
00:28:51
Speaker
In the Grabby Aliens model that you've developed, it must be compatible with us being alone in the universe. There must be some probability within that model that we are the only civilization. But if I understand it correctly, it's just very low. But maybe you could go over again why it is that
00:29:13
Speaker
We couldn't just be alone, and this is the most straightforward explanation for us not having discovered any alien civilizations. So this relative chance of our appearing now versus late depends on two parameters that we show a graph of in our main paper. One of the parameters is the number of heart steps, and the other parameter is how long lives a star can host life.
00:29:43
Speaker
So if we assume that even the longest-lived stars, the planets around them can host life and then life could wait to appear, then that parameter is at its maximum. And that the other parameter is how many hard steps I said the history of life on Earth suggests roughly six. And if, again, if it's a factor of
00:30:07
Speaker
you know, a thousand times longer and six steps, then that's a factor of 10 to the 18. So we are 10 to the 18 early, i.e. only one in 10 to the 18 civilizations would appear earlier than us under those parameters. So the way to explain
00:30:23
Speaker
our earliness without invoking our model of the universe is filling up with aliens would be to push those two parameters as far as they could go toward the low end of the spectrum. That is, you can say, no, long live stars just can't host life. It's just not possible. Only short live stars like ours can host life. That's just it.
00:30:45
Speaker
And then you could also say, and there really weren't very many hard steps. It looks like there were, but that was just a statistical fluke. Turned out there was only two steps or one step. And if you could, if you're willing to make those assumptions, then you could say, and then we're not terribly early relative to expectations if you make those assumptions. And then the universe is empty. We're the only ones.
00:31:09
Speaker
When you're thinking about when we have appeared in the universe, so are you just taking the current time from the Big Bang? Because it's not entirely obvious how we date ourselves here. Could we date ourselves from the first emergence of life? Then we are three and a half billion years earlier.
00:31:34
Speaker
Or how do you think about how to date humanity as a rival? Well, what we're doing is we're making a simple statistical model that predicts when advanced life would appear. So the model has a planet first has to appear. A star has to have a planet. So you have to have the kind of stars that would have planets and maybe not the first generation of stars don't. But, you know, you have a first generation of stars creates heavy elements, then the next generation of stars will have planets.
00:32:02
Speaker
And that next generation of stars will have too many explosions going off nearby because they've got all these very short-lived stars that are lasting a short time and exploding. But those go away because they explode. And then a little later, we've got a lot of stars around with not too many explosions and planets that can have life. And now we have the weight to how long it takes for advanced life to appear. So we can calculate this distribution of which planets could host life.
00:32:31
Speaker
when they appeared and how long they last and then we can say for each planet how long does it take for advanced life to appear i.e. what's the chance as a function of time on that planet and we're just taking some integrals here and combining them and that's what's giving us this distribution over time of when advanced life would appear if the universe would wait empty for it.
00:32:55
Speaker
And we have simple models of when stars appear and when the habitable stars appear and the distribution of how long they last. And we can just fold that into a simple mathematical model of when advanced life should appear in the history of the universe. And that's the thing we are using to compare to say that we're early relative to a model of when we should expect to appear.
00:33:17
Speaker
You mentioned earlier that if humanity expands into the universe, we will do so during the next 10 million years.
Potential for Human Space Exploration
00:33:25
Speaker
Why do you say that? Well, our evolution has been enormously rapid in the last million years, really. And perhaps accelerating. Yeah, and not just perhaps, definitely accelerating. Definitely accelerating.
00:33:41
Speaker
So there's a history of life on Earth can be summarized in terms of eras of increasingly accelerating growth. There was the rise of say animal brains from say half a billion years ago. And animal brains were say doubling roughly every 30 million years. And then humans arrived with their especially large brain, which could support culture. And then we started doubling roughly every quarter million years.
00:34:08
Speaker
a factor of 120 faster, and then humans switched into a farming mode, which allowed the number of humans to double roughly every thousand years, a factor of 250 times faster. And then a few hundred years ago, the Industrial Revolution appeared, which has allowed the economy to double every 15 years, which is a factor of 60 faster.
00:34:30
Speaker
And so at the rate we've been growing lately, we would easily fill the entire observable universe in a few thousand years. And we know that's not gonna happen. So clearly growth has to slow down, but still we are capable of very fast growth at the moment. So it's just really hard to imagine. Our growth would slow down so much that we couldn't achieve say space flight within 10 million years.
00:34:57
Speaker
Do you worry that these modes of existence for life are arbitrary? Do you think that if you took 10,000 different alien scientists and asked them to categorize modes of life on Earth, would they come up with the same modes that you just mentioned for me here? Well, the key phenomena is going to be that if you have different parts of the Earth that are in different sorts of modes, whichever part is in the mode that grows fastest will
00:35:26
Speaker
just come to dominate the rest. So there's a selection effect for finding the fastest growth modes possible. So on different planets and different civilizations, they may just have different kinds of modes, but they will all have that same selection effect. They will all start out growing slow, and then different parts of them will bounce around trying out different new modes. And if they ever find a new mode that just can grow much faster, that new mode will quickly take over and displace all the rest.
00:35:55
Speaker
And that's what we've seen so far. That is, humans could grow faster than other animals, or displacing the other animals. Then farming could grow faster than foraging, and farming displaced foraging. And industry could grow faster than farming, and industry is displaced farming. And then another mode may appear. My book, The Age of M, is on one possible theory, brain emulations. But the key idea is whatever new mode appears that could grow much faster than the existing mode, it will just quickly displace the existing mode.
00:36:21
Speaker
And when we're talking about growth rates, now we're talking about something objective, and it is no longer simply a subjective categorization of modes of life on Earth. Right, that it's about the rate at which its physical power can grow. Its direct physical impact, the energy it can command, the matter it can command, the things it can do, these things are just growing at these growth rates.
00:36:48
Speaker
Robin, if humanity manages not to destroy itself and if we expand into the universe, when will we meet aliens?
Encountering Aliens in a Billion Years?
00:36:58
Speaker
So as I said, we have a three-parameter model. We can fit each of the parameters to the data. The fit is rough, but we can get each parameter, say, within a factor of four, maybe even a factor of two. And that allows us to estimate a distribution over these models. And we can ask within each model, when do we meet aliens? And so there's a distribution here, but roughly a billion years is when we would
00:37:23
Speaker
meet aliens only of course conditional on our heading out to meet them. If we wait here to meet them then it would take twice as long because of course you know we can cut down the speed if we're traveling and they're traveling at the same time but of course we have to last that long so we would have to become either loud or a very long-lasting quiet civilization in order to meet the aliens.
00:37:44
Speaker
What do you think is most likely that we, in what mode are we most likely to survive by being quiet and long lasting or by expanding outward? Unfortunately, I'd say the most likely scenario is we don't survive. Most likely we'll be quiet and most likely we won't survive as quiet. And that would be the most likely outcome for our civilization. It's not the outcome I'd prefer, but it has to be the one I'd guess.
00:38:12
Speaker
So this model I've been talking about tells us the distribution of loud aliens in space. It says, for example, they appear roughly once per million galaxies, and we meet them in a billion years. But this is only the distribution of the loud ones.
Distribution of Alien Civilizations
00:38:26
Speaker
Now, there's a ratio, say between quiet and loud, and that ratio is important for two things. One is how close is the nearest quiet? If there are a million quiet per loud and they appear once per million galaxies, why then there might be one quiet per galaxy, and then that suggests the nearest quiet might be pretty close. But the other thing this ratio tells us is our chance of becoming loud.
00:38:53
Speaker
We're now quiet, and if only one in a million becomes loud, then we only have a one in a million chance to become loud, which is not very good chance. So, you know, I could believe optimistically, maybe this ratio goes down to one in 10, and then there's only 10 quiet per loud, but that still only gives us a 10% chance. And what determines this ratio? Well, it's...
00:39:17
Speaker
all the different paths the civilization could take and what paths it does take and which of those paths result in anyone leaving. So the remarkable fact about interstellar colonization is that it only takes one colony ship leaving the solar system that successfully heads out and lands somewhere and starts another colony to end the isolation and the quietness of our civilization. One colony ship could make all the difference.
00:39:45
Speaker
And so to prevent our becoming allowed requires that our descendants basically prevent that one colony ship from ever happening for as long as our civilization lasts. So if our civilization lasts for a billion years, then every year for the next billion years, they have to prevent any colony ships from leaving.
00:40:04
Speaker
That seems like a very difficult task. So why, given that you just said that, why do you believe that humanity will stay quiet? Will we succeed in preventing anyone from venturing into the universe?
00:40:16
Speaker
So as I said, over the last century or so, we've been slowly accumulating a stronger world community and lagging behind that, but coming along will be a stronger world governance.
Governance and Technological Expansion Control
00:40:27
Speaker
We like that. Humans like this world community. It takes us back to our forager era of making decisions together and not allowing rampant competition to determine what happens. We will get slowly better at enforcing the wishes of this world community and world government.
00:40:45
Speaker
Surveillance will get stronger. Detection will get stronger. Social conformity pressures will get stronger. We will just get better at managing this strong world government and the strong world community. And I fear and expect that it will rot. So systems today that like large software systems, even relatively small ones, all consistently rot. And pretty much all organisms consistently rot.
00:41:16
Speaker
What do you mean by rot here? So in software, the sign of rot is that as you change a software system to make it adapt to changing conditions, adding features, changing the hardware, changing customer desires, as you change software systems, the changes you make tend to create more interdependencies. They tend to make the system less modular. By making it less modular, they make it harder to usefully change. So over time, it becomes more
00:41:46
Speaker
fragile, more interdependent, and harder to change. And in fact, pretty much all large software systems are thrown away and replaced wholesale from scratch periodically. That's just our world of software, and most people don't know that about software. But it's parallel to, say, biology, which produces long-term evolution and progress by having many organisms created that rot over time and then die and then be replaced by new organisms.
00:42:13
Speaker
a future human world government would also rot in a way. And when you say that, the analogy here is supposed to...
00:42:22
Speaker
to be that it becomes less effective. Even today in, say, the United States, we've had one of the longest-lived governments on the Earth, and therefore our government systems are one of the longest-lived systems on Earth. And so if you look at the slow accumulation of government agencies and laws and rules, I think we already see rot. We already see that these rules are getting longer and more interdependent and allowing less change, and that's just
00:42:54
Speaker
long timescales and other nations haven't suffered as much because their systems are newer. Do you think that such an integrated future for the world would prevent anyone from leaving and thereby would keep us as a quiet civilization? Well, there's two parts to the story. One is that they would want to prevent people from leaving.
00:43:18
Speaker
And the other is that they would slowly accumulate more complexity in the systems, which would include more regulation and more obstacles and tentacles controlling innovation and change, such that they would be better able to prevent this interstellar colonization. That is, an interstellar colony will have to build a big ship somewhere, create a launcher of some sort to support it, and it's not small.
00:43:47
Speaker
and it would be noticeable and it would require supporting technologies to be developed. And so that would give the rest of the civilization plenty of warning to decide if they approved.
00:44:00
Speaker
If we imagine that we could become more and more technologically advanced, wouldn't it become easier and easier to build a spaceship and venture into the universe? And so if spaceship technology is democratized in a sense, wouldn't there be some group somewhere who managed to venture into the universe?
00:44:21
Speaker
Yes, if you imagine holding surveillance and control constant while you increase local abilities and lower the local cost of doing something and raise the total size of the economy, then yes, you have to expect an increasing chance of any one deviation allowing such a thing.
00:44:41
Speaker
I expect that as technology improves we will also be improving centralized control and surveillance and conformity pressures and that we will slow down our ability to innovate through the rot that such a centralized system would induce. So there's a race here you see between our technology improving and innovating and the slowly accumulating rot of a world community and government that will
00:45:08
Speaker
prevent change. So already we are seeing in the last half century many areas of technology where innovation has been slowed greatly or even stopped because the world community doesn't like it, say nuclear power.
00:45:24
Speaker
Nuclear power at a physical level has enormous potential. And before nuclear power started, many science fiction people imagined quite reasonably that when we had it, we would use it. And they could calculate how much we would get out of using it.
00:45:40
Speaker
the visions of a vast technological advanced future that people were imagining in say 1930, that wasn't crazy imagination, that was reasonable given the assumption that when we had nuclear power we would use it. We have chosen not to use nuclear power by basically heavily regulating it and preventing anyone from using it. And we are going to do that with more and more kinds of technology. This is your most likely scenario for the future.
Human Expansion and Meeting Advanced Civilizations
00:46:10
Speaker
But what if we actually managed to spread into the universe? If we meet another alien civilization in a billion years, as we mentioned before, can we say anything about which civilization, whether humanity will be more advanced or whether the alien civilization we meet will be more advanced? So I think it's pretty certain that within, say, a billion years,
00:46:34
Speaker
we and they will have just asymptoted with technology. We will all just know all of the technology, at least all the simple physical technology. We will neither side would have a technological edge. But they may well be organized differently. And maybe their different form of organization would make it difficult for us to understand them and maybe even to strategize in the light of them. And so I think
00:46:59
Speaker
they will be very interested to learn about each other in order to see how they're organized and what sort of social and organizational technologies they've adopted and how far they've gotten with them. So the first thing that will happen, of course, is that we would start to expand, right? And then once we started to expand, we would lose that internal coherence, we would lose the central control, and then we would have a lot of competition and selection.
00:47:24
Speaker
There would be wars, there would be fierce competition that would have destructive side effects. And our descendants would then evolve to become different. And so the first era here, after the era of global coordination and global harmony and all singing Kumbaya, standing on the mountain, is that we spread out and compete and change. And that would be somewhat wrenching. And it could happen very rapidly. And then once
00:47:53
Speaker
We had that we would then continue to improve our technology, but now in a world of competition and selection. And then we would ask them tote with technology, perhaps within say a million years or 10 million years. And then we would keep expanding within whatever degree of coordination we could manage to achieve at a local level, given this larger scale competition. But then another important thing would happen before we met other
00:48:22
Speaker
loud aliens is that we would meet quiet aliens or their ruins. And that would be the main data that we would have about the loud ones. We would know about our history and we would wonder about the history of the loud aliens we might meet. And the main data we would get is the other quiet alien civilizations that we might come across and say, get signals from a distance about when they're still active or the ruins of them when we finally physically came across where they had been.
00:48:52
Speaker
and we will be extremely interested.
00:48:55
Speaker
in whatever information we could glean out of the quiet ones. And for example, if the ratio is 1,000 to 1, then we expect to see 1,000 of them before we get to the nearest loud one. And maybe we could learn something about how they never expanded, maybe how they came to destroy themselves. And we could learn something that we could avoid doing there. And then for each one, we'd say, well, if this one had become grabby, had it become loud, how would that have happened? And what would they have become like, perhaps?
00:49:23
Speaker
We'd be trying to guess for each one of them what a grabby version of them would look like. And that would be our best guess about the actual grabby ones that we'd meet. What if we looked up into the sky tomorrow and discovered what looks to us to be a grabby alien civilization? What would this mean? Well, that would mean that there was some signature of them that was subtler than I'm expecting.
00:49:49
Speaker
That is, when they change their volumes, it's less of a change than I was expecting, but it's still perhaps a noticeable one. So we figure out the right frequency and the right sort of structures to be looking for, and we go, aha, look at that sphere. It's very different from the stuff around it, right? So we'd have identified a gravity alien civilization, and we could then immediately estimate how long till I get here. We could look at the speed at which they're expanding and see how far away they are, and we'd know our deadline when they would get here and then when we would meet them if we had it out to meet them.
00:50:20
Speaker
And, you know, most likely then this would mean they were expanding slower than I had thought when I assume that we, there are no ones, none in the sky. And of course we see one, we'll probably see more if we look in other directions. And we would now estimate the, say the most rapid expansion speed might be a 10th of the speed of light or even a 20th, right? We would, we would know that number and we would then know
00:50:43
Speaker
when we would meet them. And we would, of course, you know, have our whole future perception of our future changed, right? We would know either we choose to stay quiet and wait till they get here, at which point we will be at their mercy, or we will choose to become grabby and go out and meet them halfway. And we will know that that can only be done at a certain speed. It's just not possible to go faster than whatever speed we're seeing, because that's probably the fastest possible.
00:51:13
Speaker
And we would, of course, want to look at them and get some sense of what they're like internally because that's predicting our future. That is, whatever they seem to be like inside is what we're going to become like. And so it's like looking at a time machine. We would be looking at our future by looking at their structures and their patterns.
00:51:30
Speaker
But on your model, this would be very unlikely. If we saw some civilization, we would see it long in advance, and we would see it by now. We wouldn't simply, tomorrow, by some better technology, see something that we hadn't seen before. It's not so much on our model. It's on my judgment that most likely whatever changes they would make would be pretty visible. I could just be wrong about that. But that's not so much from the model, it's just from this judgment that
00:51:59
Speaker
most likely a civilization that had, say, been in some space for 100 million years, you know, changing things to its heart's content, those changes would be pretty noticeable. That's what I've been presuming, but I could just be wrong about that. Yeah, so your adjustment here is that
00:52:16
Speaker
What's the alternative scenario? It is that an alien civilization would control a region of space but not do anything that's visible to us. So maybe what they're doing is on a very small scale or is on some physical feature that we don't understand that they're changing. It would be on a scale of like many galaxies. Like there'd be a sphere that covered, you know,
00:52:42
Speaker
a thousand or a million galaxies out there. So they would have moved across a large scale, but somehow they wouldn't be changing these galaxies very much.
00:52:50
Speaker
somehow they'd be leaving the stars alone, say. So maybe the idea there's, look, there's something between the stars that's much more useful than the stars. And once you've confined those things, who cares about stars? You just ignore the stars, because you've got all this other great stuff to work with, you know, and there'd be all this other stuff we don't even know about. So once we saw that, we say, hey, that other stuff might be around here, too. We should go find that stuff around here. What's all this great stuff they could use that isn't stars, because they're apparently doing stuff and they don't even care about the stars.
00:53:14
Speaker
Or maybe it's a civilization that actually acts like what you described earlier in this interview, kind of preserving the ecosystems of different planets they find in a very coordinated way. But I just find that's possible. That would be implausible that all of them would look that way. So you can look at one of them. And so we might look at different ones and say, how similar are they? So the more different they are, the more scope there is for each one's history and system of governance to have affected what they do.
00:53:44
Speaker
Okay, we've been talking about aliens and where they are and so on.
Cosmology's Role in Human Perspective
00:53:49
Speaker
Can we change our actions in any way if we begin believing in the gravity aliens model? Should we do anything differently based on this theory? Well, most people through history have thought that cosmology mattered in the sense that what you think about where you are in all of space-time affects how you think about yourself.
00:54:13
Speaker
It's your place in the universe. So if this is true, we have to change our perception of our place in the universe. You know, ancients, when they had a cosmology, it was usually full of active, interesting agents who had agendas and conflicts. And their stories of their cosmologies included these powerful agents and their agendas and their conflicts. Lately, when we
00:54:43
Speaker
scientifically advanced humans have told the story of our cosmology, it's kind of boring in the sense that it's all dead. There's just these particles flying around and these gases swirling and they swirl and they fly and they glow and they explode and that's the cosmology we're in. It's a dead cosmology that's been dead so far and in the usual story will be dead forever except for this one little sliver where we are which hardly matters.
00:55:13
Speaker
If raviolians are right now filling half the universe and changing things dramatically and another billion years will fill it all, then cosmology is a pretty different story.
Moral Implications of Other Civilizations
00:55:24
Speaker
It's full of active agents with agendas, and we could be one of those agents and take our place among them if we so choose. And that becomes the new cosmology. And it would mean that we are much less important in some cosmic sense than we might otherwise have thought. If we thought we were alone in the universe, then there
00:55:47
Speaker
at least on some moral theories, we could have a duty to survive and expand and flourish in the universe. But if the universe is already filled with alien civilizations, maybe our survival is less important in some sense. Well, I mean, the thing before was that people had an unbounded estimate of how much we could matter. However much it was, it could be even bigger than that. And in this case, it would be bounded.
00:56:15
Speaker
Now, it's still pretty big. That is, our choice to be quiet or loud would basically affect the nearest million galaxies for the next billion years. And that's all. But that's a lot. The nearest million galaxies for the next billion years, it's a lot. There are lots at stake there. So I think it isn't like, oh, now we don't matter anymore. It's just not infinite anymore. It's a bounded amount that we matter. But it's a lot.
00:56:41
Speaker
And it changes our self-perception, perhaps. Well, so it's not just like there's this volume that will just stay dead and empty unless we make it alive. That's one of the things at stake. But another thing that's at stake is that when we finally meet the aliens a billion years from now, that will just be the beginning of another era that might last 100 billion years, wherein we and these other alien civilizations will be part of a universe-wide community of aliens.
00:57:09
Speaker
And in this community, we will interact. And we will each learn about each other. And then we'll each have to decide which things about each other are we impressed by and want to emulate. That is, we will be culturally influenced by each other. And therefore, we could each aspire to be worthy of emulation in some interesting way. Not in all ways, but we could hope that
00:57:33
Speaker
our the universe will have descendants of us not just because we control some region of space that we defend but that because we have something of value that others recognize as having value and that they take it on and spread it. Do you think that in a billion years the notions we're talking about now will will make sense so does it make sense for as can we even talk about once one
00:58:02
Speaker
enormously advanced civilization admiring another enormously advanced civilization. Do you think we risk kind of extrapolating our concepts too far here? This is the job of a theorist to basically identify our strongest, most powerful theories and to judge their robustness, to judge how wide a range of circumstances they plausibly apply to. We have the same task with physics.
00:58:31
Speaker
you could say we only know the physics of the universe we're in. And in the future, they will, you know, explore other physical possibilities. And therefore, we have no concept of the future physics. And they can't even talk about the volume of space they'll be in at the time it'll be, they'll meet them. And none of that will be meaningless because our concepts are meaningless. That seems to me to go too far. I think the concept of space, for example, and time are both going to be robust concepts that last for a long time. The speed of light limit on travel, I think, is robust. And that
00:59:00
Speaker
will project and then if I look at social and biology and I say what are the most robust concepts seems to me selection and reproduction are pretty robust concepts and they will last so I can talk in terms of the future in terms of selection and reproduction and that's what I'm trying to you know use those concepts here we will spread out and then we'll interact and there will be cultural selection among that mix and some things some elements will reproduce and others won't and
00:59:29
Speaker
we can aspire to have our elements reproduce. Robin, thank you. This has been extremely interesting. It's been great. That's it for this episode. On the next episode, I talk with Robin about the potential dangers of AI development and why Robin is skeptical of such scenarios.