Dissolving the Fermi Paradox [pdf]
jodrellbank.manchester.ac.uk
jodrellbank.manchester.ac.uk
Possible solution to the Fermi paradox: there is no paradox. The normal approaches find that there should be a very large number of civilizations by plugging point estimates into the Drake Equation, but multiplying point estimates (as opposed to probability distributions) with each other gives you misleading results.
As a toy example, if you multiply nine factors together to get a probability of life per star, each of the factors a random real number drawn uniformly from [0, 0.2] and the point estimate for each being 0.1, then the product of the point estimates is 1 in a billion. This would translate to an expected 100 life-bearing stars, given 100 billion stars. But if you instead combine the probability distributions, you get a median number of 8.7 life-bearing stars (the mean is still 100).
Going through the literature to estimate reasonable prior distributions for different values in the Drake Equation, you get much more pessimistic estimates for the probability of life in the universe; the priors chosen by the authors suggest a 40% a priori chance for life only emerging once. We really might just be alone.
In a universe that's practically if not actually infinite in size, it seems to me that no species is ever big or strong enough to be safe from a bigger, stronger one. And thus any rational species interested in self-preservation (I hope this includes us) simply MUST hide. Forever. We're not very quiet but we're also extremely harmless at a galactic scale so I imagine if I were an alien species that noticed us, I'd just leave us alone as bait to reveal any less cautious species.
Following that line of thought, I'd be much happier to believe we're simply alone. :-)
https://en.wikipedia.org/wiki/Drake_equation#Equation
This information really should have been in the first slide.
It's hubris to (a) know the universe is probably infinite and (b) assume that life evolved anywhere within our slice of it.
Infinite! The universe seems to be infinite. If that's true, it seems just as likely that all intelligent life in the universe is completely alone.
Start plugging in more reasonable numbers for expansion say a smaller chunk of c and reasonable assumptions of requiring old rocky planets etc, and there could be 10^10th such civilizations and we just can't see them.
Assuming things based in our lack of knowledge, and deducing that there are no keys because we can't find yet any under this narrow streetlight are my biggest concerns on the paradox. Why "insufficient data for meaningful answer" is not an option?
And this paper takes the paradox hypothesis as granted and just tune for the worse some variables.
The point of the Fermi Paradox is simple: according to our best knowledge, the sky should be full of alien civilization. It's not. Therefore, something we know is wrong.
The point of the linked document is likewise simple: if you properly account for the unknowns in our knowledge, it's actually consistent with a lack of alien civilizations in the sky.
There's nothing wrong with declaring "insufficient data" and moving on. But there's also nothing wrong with analyzing the data that's available and coming up with the best answer you can.
The last four terms in the Drake equation are completely unknown. There's no point even trying to estimate them, because we simply have no clue how to estimate realistic distributions. We don't even have good data yet on the frequency of earth-like planets throughout the galaxy, because our planet-hunting techniques aren't sensitive enough to provide useful accuracy. We have some idea how many rocky planets exist in habitable zones, but there's no way to get from there to an accurate estimate of truly habitable planets.
The third term is only slightly more amenable to estimation. What does "life" mean? Clearly for Drake it means life that can send signals we might pick up after a scientific search.
But it life sends something so completely unexpected that we're not only not looking for it, but likely to overlook it, then we won't see it - for many possible reasons.
What's the distribution? No one knows.
So in fact, there are no useful priors for most of the equation.
As the over-used phrase says, absence of evidence is not evidence of absence. It's evidence of absence of evidence, and it's unwise to be too dogmatic about drawing further conclusions.
Then throw in that, based on human experiences and intuition, one in a trillion or whatever is an incredibly rare event. But that isn't a fair estimation for an event that may be truly rare.
But this statement isn't true. We've looked at a tiny fraction of the galaxy for radio signals and didn't find any in that small area that looked like they came from an intelligent origin (actually, we found one, the Wow! signal). But from what I've read - using the equivalent of the Arecibo dish, even the closest star to earth wouldn't be able to pick up our general transmissions. So first we have to assume that civilizations use radio transmissions for a very, very long period of time, and don't replace it with some other tech (so the earth wasn't only receiving them from, say 200,000 BC to 150,000 BC or 1200 BC - 200 AD before the civilization moved on to gamma burst communication). Then we need to assume that these signals are much stronger than the ones we're currently emitting. And then hope we get lucky and look in the right spot for them.
So after a small amount of searching we haven't yet been able to find one specific type of civilization using one specific type of technology in a very particular way (not even in the way we use it). Even if the universe is teaming with life, there's nothing paradoxical about that.
I have never found the 'paradox' convincing for exactly this reason. The presumptive extrapolation in its formalization is breathtaking.
It is primarily useful IMO for posing an estimate to answer a different question from the one people believe it does, which is simply, 'what is the incidence of life, much as we know it...?'
...where 'as we know it' is extremely narrow and rests upon the equally narrow 'physics as we know it.'
We are smart monkeys, but while we have learned a breathtaking amount in the last couple centuries, our overconfidence in what we think we know remains constant.
You can hold most of the assumptions constant and still come up with many reasons for the 'silence' of the skies, none of which reflect upon the incidence of intelligent life or advanced civilization... :P
http://www.popularmechanics.com/space/deep-space/a26575/some...
Subreddit devoted to the star: https://www.reddit.com/r/KIC8462852/
Relevant xkcd, especially the alt-text:
"The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space--each discovered, studied, and remembered by the ones who made the irrational decision."
:(
> Conclusion 2: the great filter is likely in the past
Is there an article to go with these slides? I'm somewhat competent with probability theory and I found it hard to follow with all the unmarked graphs and unexplained parameters.
> Anders Sandberg, Stuart Armstrong, and their co-author Milan Cirkovic published a paper outlining a potential strategy for advanced civilizations to postpone computation until the universe is much colder, and thereby producing up to a 10^30 multiplier of achievable computation. This might explain the Fermi paradox, although a future paper from FHI suggests there may be no paradox to explain.
If on the other hand the early terms are much lower than expected, as this PDF is discussing, then the sum total of them could be considered the "Great Filter" and we could be past it. It's fine to just lump them together from our point of view, since at the moment we don't have the data to figure out which gate is "really" the determinative one.
Wandering down my own thoughts here: The Copernican Principle, or perhaps better termed in modern parlance the Copernican Heuristic, that we are nothing particularly special, has had a good run. But it is just a heuristic, and one whose adherence has arguably been driven more by a science v. religion feud than logic or data, and whose underlying logic in the past 50ish years has metastasized into "Some religious people I don't like think Man is unique, they're wrong about everything, therefore Man is not unique in any way." But lately the Copernican Heuristic has been showing a lot of strain. Our solar system may not be unique, but it is increasingly looking like it may indeed be unusual, for instance. The Rare Earth arguments have never gone away and I think a lot of the dismissal of that idea has also come from "Religious people like the idea of the Rare Earth and some of them are arguing for it, religious people are wrong about everything, therefore Earth is not rare." [1], because scientifically they look as good as anything else on the subject (namely "those arguments seem to fit our lack of data as well as anything else", which is a pretty weak endorsement). And per the PDF under discussion, a lot of the universe really starts to make more sense when you start to seriously consider the possibility that, yes, we may in fact be very unusual, if not perhaps truly unique.
[1]: Those are not the only arguments here, nor are they the best; I'm just saying that it is my subjective sense that the debate over the past few decades has often been very skewed by the underlying presence of this argument, even when not necessarily spoken. It is my perception that this debate has often been had under unspoken ground rules where all the discussion must occur in such a way as to ensure that the religious people are unable to point to anything as evidence for their side. It... doesn't make for the best conditions to do science under.
The number of civilizations, N, is assumed to be equal to the mathematical product of
- the average rate of star formation, R∗, in our galaxy,
- the fraction of formed stars, *fp*, that have planets,
- for stars that have planets, the average number of planets *ne* that can potentially support life,
- the fraction of those planets, *fl*, that actually develop life,
- the fraction of planets bearing life on which intelligent, civilized life, *fi*, has developed,
- the fraction of these civilizations that have developed communications, *fc*, i.e., technologies that release detectable signs into space, and
- the length of time, *L*, over which such civilizations release detectable signals.
Which is the core of Fermi paradox, and therefore it still stands.
Now lumpers v splitters aside there are plenty of tool using, problem solving, communicating species on the planet right now. And they cover the spread too: Octopuses, apes, birds; ants individually are of course dumb as a brick but colonies have actually invented agriculture.
Yeah, ants probably will never make it into space and birds lack fine dexterity to build a rocket ship even if there is a parrot Newton/Ramanajun but that doesn't mean we won't find something to have a conversation with if we can go to them.
fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into spaceThen humanity has a long way to go before proving its intelligence.
What would you say if someone came along and said, “Hey, we want to genetically engineer mentally retarded human infants! For reasons of scientific progress we need infants with certain cognitive and emotional deficits in order to study their postnatal psychological development - we urgently need some funding for this important and innovative kind of research!“ You would certainly think this was not only an absurd and appalling but also a dangerous idea. It would hopefully not pass any ethics committee in the democratic world. However, what today’s ethics committees don’t see is how the first machines satisfying a minimally sufficient set of constraints for conscious experience could be just like such mentally retarded infants. They would suffer from all kinds of functional and representational deficits too. But they would now also subjectively experience those deficits. In addition, they would have no political lobby - no representatives in any ethics committee.
If they had a transparent world-model embedded in a virtual window of presence, then a reality would appear to them. They would be minimally conscious. If, as advanced robots, they even had a stable bodily self-model, then they could feel sensory pain as their own pain, including all the consequences resulting from bad human engineering. But particularly if their postbiotic PSM (phenomenal self-model) were actually anchored in biological hardware, things might be much worse. If they had an emotional self-model, then they could truly suffer - possibly even in degrees of intensity or qualitative richness that we as their creators cannot imagine, because it is entirely alien to us. If, in addition, they possessed a cognitive self-model, they could potentially not only conceive of their bizarre situation but also intellectually suffer from the fact that they never had anything like the “dignity” so important to their creators. They might be able to consciously represent the obvious fact that they are only second-rate subjects, used as exchangeable experimental tools by some other type of self-modeling system, which obviously doesn’t know what it is doing and which must have lost control of its own actions long ago. Can you imagine what it would be like to be such a mentally retarded phenomenal clone of the first generation? Alternatively, can you imagine what it would be like to “come to” as a more advanced artificial subject, only to discover that, although possessing a distinct sense of self, you are just a commodity, a scientific tool never created and certainly not to be treated as an end in itself?
If that argument is taken seriously then it should already be starting to apply to things like the Google spam filter, but once you take it out of the space of hypothetical possibilities like that and apply it to real code it becomes obviously absurd. There is less than no reason to believe that the only possible artificial intelligence will be simply humans that live in machines and have all their needs and desires, and even such AIs that are nascent in the world today already have grotesquely different architectures than that, with little reason to believe making our spam filters or car navigation systems "more human" in the existential sense would even remotely improve them. Why would my car's navigation system even need to be able to represent "a sadness that I'm just a car navigational system instead of a Real Boy", let alone actually manifest it?
By far the greater risk in that world is the economy/universe optimizing out everything that makes humans human until the entire universe is simply a highly efficient philosophical zombie, rather than the risk that every last subsystem of everything in the world is secretly going to be a human-class homunculus trapped in some boring task.
This, to me, is a greater risk than "evil AI." If humanity does cease to exist, it will be a slow, painless, barely observable extinction (perhaps even paraded as ascension) as we integrate with and are then replaced by the technology we've created.
I don't think this is entirely realistic, just because there's an anthropocentric bias in me that believes that humans are wonderfully useful and robust self-replicating machines, and that economically we're (1) fairly energy efficient and (2) valuable to "throw at problems" we don't want to mass produce specific silicon-based solutions to.
But I did want to thank you for pointing this out. I do think it's wonderfully naive we often ascribe human characteristics and fallacies to hypothetical general AI that we experiment with or build, as though distinctly human consciousness is somehow the epitome of achievement. It's not even in our best interest, economically or ethically, to strive for that.
Argument about conscious Google spam is quite unfair and unwarranted. In fact, if you actually consider what Metzinger has to say about necessary conditions for consciousness (for example in "Being No One" or "The Ego Tunnel"), then obviously Google spam is nothing like that.
Either way it seems to me that it may be better to err on the side of not making conscious AI in the first place rather than unintentionally making one with capacity to suffer. Especially that it may be non-obvious that it has capacity to experience pain. For example, we have already made this mistake by using curare alone as an anesthetic - presuming that a lack of automatic pain response, and ability to communicate feeling of pain means that one doesn't feel pain. That was a considerable misjudgment.
So basically Uber for aliens. (General reminder, Bayesian statistics is math not magic, one can move a few percent of uncertainty to somewhere else, or get nicely interpretable parameters if it happens to be the right tool, but it is not some kind of general reasoning mechanism, its a tool.)
One troubling fact for example is that radio signals might disintegrate into noise after large periods of time, making detection via this method impossible.
Confirmed exoplanets less than twice Earth-size in the habitable zone: 30
K2 mission: Candidate exoplanets: 520 Confirmed exoplanets: 148
https://www.nasa.gov/kepler/discoveries
These are anemic numbers; even those in the "habitable zone are either tidal locked, their solar year are weeks or days long and we don't really know what their surface is.
The James Webb Telescope will help a lot but if you look at all the species and forms of life that lived on this planet in last 4-billion years (billions and trillions) only one has evolved intelligence to the degree that it can contemplate the universe and investigate it. I think it is plausible that we could be it...or at best so far and so few in between.
Link to explanet archive: https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/np...
2700 confirmed planets out of 145k monitored stars indicates that planets are very common, around most stars, since there are an estimated 270,000 planets of similar type in that sample that just have inconveniently aligned orbits.
Similarly, 30 confirmed near-Earth mass planets translates to 3000 per 145k stars (nearly 2%!), and thus literally billions in our galaxy alone.
If life that evolved in that sort of environment managed to work its way up to the surface it could keep its lifestyle living on Kuiper Belt Objects and probably other lumps of rock and ice between the stars and possibly not have that much interest in anything that happens on our side of the frost line.
There's all the questions around how we would know what to look for, of course.
That said, this particular parameter will likeley be higher, since we have found several exoplanets, that are estimated to be habitable.
However it's worth pointing out that the Drake equation is couched in terms of probability so as long as N != 0 it's fine, there is no reason billions of civilizations can't exist no matter how asymptotically close to zero the probability of even one civilization is, it would just be weird.
I've always found the Fermi paradox quite unconvincing. And the Drake equation makes it even more obvious.
There are many things we don't know, so the default answer is, most of the time, "we don't know".
To me, it's more intuitive that we cannot expect to be alone in this galaxy. Perhaps we're the first advanced civilization, but in that case we will not be the last. The vastness of the universe make the chance of us being one-of-a-kind thing really low. If we accept that laws of physics created us, then they can happen else where. And the Drake equation gives an estimate, albeit we have no idea if the variables are reasonable.
But it also means the chance of ever communicating with a different life form is really low.
You would probably agree that no other alien civilizations speak English. Why not, in the vastness of the universe? Because while the universe is big, the possibility space of languages is so much bigger that no language will ever be repeated.
If history were such that the entire world spoke one language, we might seriously think that aliens had to speak it too.
A key question is whether life is like a language in an infinite possibility space, or is something special.
The Drake equation does not give an estimate. It gives us a train of multiplying factors to which arbitrary values can be assigned, and with it a false sense of a sound estimate.
It's like the lab coat archetype in ads: it looks sciency, but it really isn't.
We also have no idea what alien civilizations might do. Do they stick around their home star, or spread out? Do they last a long time or go extinct? Become god-like or go totally VR? Would they bother to make themselves known over a long enough period of time that other civilizations would detect them? We simply don't know.
This is important, because if we look specifically for life, it limits the scope of our imagination and search. It's SETI, not SETIL.
It raises a question, that is basically "how do we need to adjust this model to explain the fact that we've not yet met anyone?"
My own first take would be that with such a vast number of opportunities for life to arise, it would be incredibly strange if it happens only once, and to me that seems to be the most common view, at least among those who accept a physical theory for the origins of life.
Gets slightly hairier for "intelligent" life, "civilizations",advanced technology" and so on, but the same basic reasoning seems to hold.
I went to a pretty conservative high school. I had no trouble convincing conservative (evolution is a lie) christians that we are probably not alone in the universe, because it is intuitive that we aren't alone. It went like this:
* There is probably at least one planetoid per star that could support (microbial) life as we know it.
* 100 billion stars per galaxy.
* A trillion galaxies.
* In these trillions of places that could support life, there is not a single microbe? So much for God's infinite power. He must really hate life.
The sheer hubris that there isn't any life in any of the other trillion galaxies usually makes people reconsider.
Now I followed this up with the fact that we are probably never going to see any of these alien lifeforms, particularly if they are just bacteria in another galaxy. The distances are too vast.
An argument could be made that god put life exactly once in each galaxy, and that we have a manifest destiny to colonize it. (You see this argument gleefully applied to resource extraction on earth.) But I never convinced anyone to give all their money to Nasa as part of god's plan.
Probabilities are real numbers between 0 and 1. For example, 1.E-301 is one of them. But if one is to take that probability out of a hat people just blatantly ignore it.
>The sheer hubris that there isn't any life in any of the other trillion galaxies usually makes people reconsider.
Hubris is on both sides of this, isn't it? On the face of little to no evidence, how can we estimate such probabilities?
Another possibility I do not see discussed at length yet is the soft factors override the technological feasibility. The Great Filter could simply be intelligent life cannot so far get its act together enough to cooperate long enough to make it out of their cradle worlds. We ourselves simply do not have the soft tooling, not to speak of the hard engineering, to sustain consistent multi-hundred year and multi-millenia efforts, and none are even remotely on the horizon as yet. Consider: our vocabulary in major world languages simply do not have a word expressing tens or hundreds of thousands of years as a discrete quantity like "millenium" expresses a thousand years [2].
The very fastest human-made object ever is Helios 2 at 221,232 mph [3]. An order of magnitude and a tripling will get us close to 0.01c [4]. The closest rocky planet in the habitable zone we know of is Proxima Centauri b [5], 4.2 light years away. Assume we can accelerate to 0.01c in the same time it took Helios 2 from launch to its fastest point, 13 years, and it takes the same amount of time to decelerate, so 26 years total just to boost and brake. That's nothing compared to the 400+ years in between.
Okay, make it two orders of magnitude and we're talking roughly a single human generation to make the trip one-way. We still don't possess the accuracy and precision in leadership science, not to speak of governance, to say we can cram enough people into a generation ship to be self-sufficient forever, and with the certainty that they don't detonate themselves along the way. If we can't get our act together enough as a species to work out how to co-exist with Romanis for example, or mitigate externalizing/rentier behavior in management in companies (think Romani-lite behavior) around the world for another example, then we sure as hell can't even comprehend what kind of social structures it takes to spread across the nearest exoplanets for hundreds or thousands of years, not to speak of the galaxy in hundreds of millions of years.
The best we can say at this point is even if we can solve the daunting soft and hard problems of terraforming, and cramming millions of people into generation ships, and countless other goals required to envision colonization, it is a one-way trip, and the civilizations set up away from our home system are separate-but-maybe-familiar. The closest experience we have to that are the old colonial periods of the Western European powers, and even then, they had one to two orders of magnitude time delays less than we are going to experience in the foreseeable future with generation ship tech.
I'm a huge Iain Banks The Culture fan. But I recognize how paramecium-level we are in so many sectors of knowledge, craft, and skills, to reach even the first rung towards that kind of vision. I don't want us to kid ourselves on the work we must put in for our future generations to plant the seeds towards that first rung of the long ladder.
[1] https://www.quora.com/Approximately-how-much-does-humanity-w...
[2] https://english.stackexchange.com/questions/331988/is-there-...
[3] http://www.guinnessworldrecords.com/news/2016/7/nasa%E2%80%9...
[4] http://www.wolframalpha.com/input/?i=0.01c%2F221,232+mph
[5] https://en.wikipedia.org/wiki/List_of_nearest_terrestrial_ex...
Then there might be no other stars and habitable planets out there. What we see is just the ambient light approximation of the simulation.