1 - Given that we are only 14B years into a many-trillion-year stretch, our existence now is so unlikely that it's possible that we actually are the first. Something has to be first.
2 - Aliens are everywhere, but we cannot perceive them for reasons we would find disturbing. Largely, for the same sort of reasons that cave fish cannot see light or that most species are apparently unaware of humans in their environment. Essentially, that there is no evolutionary reason for humans to perceive them.
As for grabby aliens... meh. I don't find it convincing as a resolution. It contains too many unexamined assumptions, quite like the simulation theory.
I'm betting on #2. We only have our own planet to look at, but if we could somehow rank all of the species on the planet according to intelligence, just jumping a couple of levels up or down you enter a completely different world of existence. Or as I like to quip, somewhere in the middle of the ocean there's an island. On that island is an ant hill, and there's an ant at the top of it wondering: Where are all of the other ants?
I don't really find it disturbing, though. Our "best practice" to interact with other species is to try to leave them alone and watch them enjoy and live in their habitat. Makes sense that's what we're doing for the alien overlords, and I'm okay with that. Assuming aliens are around somewhere and we're using our own planet to reason by analogy, the only other two alternatives are they're going to subjugate/destroy us or they're going to eat us. Those alternatives are not so fun.
I find it interesting that so many humans assume that since we can chat with one another, aliens somehow are supposed to show up and chat with us. It's all about us. If such a thing happened, the history of massively-different cultures interacting on Earth is not a positive one.
> I find it interesting that so many humans assume that since we can chat with one another, aliens somehow are supposed to show up and chat with us. It's all about us. If such a thing happened, the history of massively-different cultures interacting on Earth is not a positive one.
We do have terrestrial aliens here on Earth and we are trying to chat with them. Dolphins, Gorillas, Chimps, Bonobos, Crows, Killer Whales... there is evidence for all of these species having varying degrees of language, culture, problem solving capabilities. Some of them, like Dolphins, sure seem damned close to our own capabilities with likely fully formed languages. We've been trying to decipher their language for 50 years with almost no success. With many of these species we've figured out pretty rudimentary and simplistic communication modes, but they clearly have much more complex communication structures among themselves and we've come nowhere close to deciphering them.
That alone tells you how difficult it's going to be to learn to talk with extraterrestrial aliens. Even our near cousins, we struggle to communicate with.
If we're examining our behavior as an analogy for the ET's however, it would suggest that either no one's around, or those who are around are so advanced that they don't think we're worth the effort to communicate with. Because we're definitely trying to communicate with the species we're aware of that we think have language.
Of course, many of the species on that list were only added relatively recently (Crows, for example).
I don't know why this hasn't come up yet, but watts per bit has fallen precipitously over the last 150 years, which means it's pretty unlikely we'd see any stray radio signals from other planets unless we managed to catch them exactly during their very brief 1-2 century inefficient stage.
And even if we're not in a "dark forest", keeping quiet is generally good social hygiene and tends to correlate with maturity. Which may be a side-effect of #2.
>If such a thing happened, the history of massively-different cultures interacting on Earth is not a positive one.
Given the sheer size of the universe, and the absolutely massive costs of interstellar travel, I have no idea why any alien civilization capable of visiting us would have hostile intent. Life is rare. Elements, even the rarest, are exceedingly common.
The thought that an advanced alien civilization would cross thousands of light years of distance to subjugate or destroy some naked apes is hilarious to me.
#2 is not satisfying. The ant might not perceive humans but if the ant is not "special" then the ant should perceive tons of other life forms equivalent to its own level, across the islands that it can observe.
Resolving the Fermi paradox by appealing to hypothetical aliens who are too high for us to perceive just feels like "aliens-of-the-gaps". The number of species on Earth with human intelligence (and quantity of such individuals) is orders of magnitude less than the number with ant intelligence. Aliens more advanced than us should similarly be that much less common than us. If humanity is not special, other aliens who are more equivalent to us are still missing.
It's nice that someone else gets #2. I often get bogged down with people refuting the notion by pointing out that we are not cave fish and are nothing like cave fish. That we have evolved to perceive everything that can possibly threaten us and that includes aliens.
Alternatively, given that the majority of the planet is water and we kind of can't really imagine a biology without it, the universe could be full of fish planets.
I'm highly suspicious of the fact that other life forms in the universe necessarily resemble our own, although I tend to think about some things that seem to be universal like the the laws of physics and organic matter. I'm not yet very convinced that the whole organic machinery revolving around RNA/DNA is universal, although I have a very deep feeling it is...
In any case, "The Caloris Network" is a reference example for me when attempting to think about how different alien lifeforms might be.
Is intelligence necessarily organic matter based? Maybe not. Maybe somewhere in the universe a spontaneous self-replicating turing machine appeared. Maybe there is life on the event horizon of a black hole, or maybe a hot type of intelligence lives inside a star.
I think we can make all kinds of wild assumptions.
> Or as I like to quip, somewhere in the middle of the ocean there's an island. On that island is an ant hill, and there's an ant at the top of it wondering: Where are all of the other ants?
That’s not a very good analogy though. The ants’ answer would be “maybe across the ocean”. And since the ants lack any tech to check or be checked by other ants that would be the end of it. It’s not naivety. If there were other ants not visible to the island, they would be fundamentally underdiscoverable.
> 2 - Aliens are everywhere, but we cannot perceive them
We can detect neutrinos with advanced instruments. We've never had an evolutionary reason to do that.
There's really just no room for this explanation. Energy and mass are one and the same. If we can detect neutrinos, but not these intelligent aliens that are everywhere, it means that they don't occupy physical space, don't have mass (and therefore must move at C only), don't use energy, don't send signals to one another, don't accelerate or decelerate, aren't involved in chemical reactions, don't interact with any of the particles we do, don't perceive light, etc. etc. At that point, they basically don't exist in our universe.
It's not enough to say "but ants don't know we exist!" -- first of all, yes they do. Secondly, you're really saying that intelligent ants who formed an advanced society, had a scientific revolution, and built instruments capable of determining the number of moons on Jupiter, still would not know we exist. That is clearly ludicrous.
And this doesn't even solve the Fermi paradox! There's clearly plenty of "room" for aliens that are "somewhat similar" to us; that is, they actually are made of protons and neutrons, etc. Where are all those aliens?
So many incorrect statements and assumptions... our current footprint would be unrecognizable from few hundred light years to even a bit more advanced civilization looking straight at our Sun. So yes there very well may be aliens just like us technology wise say 200 or 2000 or 2000000 light years away and they nor we simply wouldn't know.
We don't know what we don't know from physics, the arrogance of thinking we get it all was there numerous times and it was always a wrong emotion, we even realize it for our current theories. There may be quantum entanglement communication, higher dimensions, strings or basically anything your nor my mind can't even come up with right now. Just like cavemen simply couldn't come up with general relativity even if it was all happening right in front of their eyes.
Imagine if it turns out sentience can arise in stars, gas, dust, or minerals. Maybe they won't be advanced civilizations, more like animals we can't recognize as creatures even when they're in front of us. We might even start mining them, as eyelash mites mine us without comprehending us.
> We can detect neutrinos with advanced instruments...
"We can detect things we were not evolved to detect" is a non-sequitur, a true statement that does not refute the original speculation. Because we can detect some things we were not evolved to perceive, does not mean we can therefore perceive aliens.
It's a difficult concept to communicate. Empirically it's literally meaningless. Even the concept of meaningful vitiates discussion of this idea.
Everything we are is perception, pattern recognition, threat assessment, problem solving. That there might be something important in our environment that we are simply not built to respond to is far easier to reject outright than to consider. This is why it's my favorite resolution to the Fermi Paradox, because it is so challenging to consider.
Our cognition has evolved only slowly compared to our rapid technological advancement. Perception is not simply detection, but also cognition. Though we detect such previous unknowns as neutrinos and invisible electromagnetism and peculiarities of quantum physics, we think about them differently than that with which we are familiar only with expensive and difficult training, and even then it's arguable that we are modeling reality itself or modeling only our limited perception of reality.
In short, while we are impressed with our abilities to understand our reality, we are still constrained by our evolved cognition to think effectively only about living by hunting and gathering in Earth-like conditions.
First one doesn't really make much sense. There are so many intelligent lifeforms on earth (whales, octopods, birds, monkeys, canines) and intelligent hive-minds (bees, ants, termites) that the leap to exponential tool use doesn't seem like something that would take anything close to 100B years, let alone trillions of years.
As for number two, it's hard to comprehend a response that is reasonable because our cognition may be part of the "disturbing reasons" right?
The theory I more and more think is probably right is that there is some major aspect of the universe that we get wrong. What is more likely, humans thinking they understand something when they don't or that no life form was able to spread amongst the stars in billions of years? I have plenty of lived examples of humans with false knowledge.
It's a sort of meta Drake equation. [Likelihood humans are not as wise as they think they are]*[rest of drake equation] and I think the drake equation, as stated, correctly leads to the term "Paradox" given the conventional understanding of science as communicated by scientists.
All the intelligent creatures of present earth took at least the 2-4 billion years to come into their existence. The universe 13 billion years old but maybe the early universe was too hostile to allow progress, maybe it required many billion years to have the occasional planet with a wide and useful variety of elements.
"the leap to exponential tool" - the current human leap to exponential resource consumption seems to be colliding with the limited and fragile structure of the earth (IE, CO2 pollution is pushing to catastrophic global warming). A fair number of decision makers seem to expect some tech fix to appear when every indication is it won't. My point is "getting to stars" would require technological progress in a situation where a species learns to curb an appetite for exponential growth, something human beings certainly haven't achieved.
> First one doesn't really make much sense. There are so many intelligent lifeforms on earth ... that the leap to exponential tool use doesn't seem like something that would take anything close to 100B years, let alone trillions of years.
I don't quite understand your logic here? The big barrier(s) doesn't seem to be tool use, but rather 1) the formation of life itself, and then 2) the move from single-celled organisms to multicellular organisms (this took 2 billion years on earth, so is clearly a very difficult step).
3 There is big cost or downside to galaxy-wide expansion that we don't get and that limits expansion, like travelling interstellar distances being far harder than we imagine in practice.
4 We are weird in that we want to expand like this, but others don't, similar to how chimps appear to be well able to express themselves in sign language, but appear to simply lack any urge to do so. Similar to your #2.
5 There simply isn't a compelling reason to expand galaxy-wide by the time you can. Reproduction must be stabilized in some way if mortality is taken out of the equation, which will probably happen earlier, a sufficiently advanced understanding of cosmology and physics might conclude there isn't any danger that can't be managed or that spreading out over a few lightyears wouldn't guard against sufficiently well. Getting rid of evolutionarily helpful urges that become a burden in a post-evolution world might be a filter by itself, so this is similar to your #2 in that they're different in a way we can't easily conceive.
6 Once you can make any existence you want happen (by some kind of unimaginably advanced VR) and have tech keep everyone safe and alive indefinitely, the actual universe might start to seem underwhelming. Better to live out the millennia in a perfectly convincing hedonistic metaverse. I could see that happen to us, come to think of it.
> 3 There is big cost or downside to galaxy-wide expansion that we don't get and that limits expansion, like travelling interstellar distances being far harder than we imagine in practice.
This is my thought. Without FTL travel you have to go the slow way. Probably much less than C thanks to the rocket equation. But in order to do this you need to build a spacecraft capable of surviving for centuries or longer with absolutely no outside support, not even solar power.
But if you can build that you have effectively unlimited space in your own solar system. Why bothering to travel to a different solar system at that point? Maybe if you have used up literally all of the resources in your current solar system, but that's a multi-billion year process. So you might only need to make the trip once or twice in the current age of the universe. But even that seems less likely than just developing really good recycling systems.
So the solution to the Fermi paradox is that by the time you have the tech to travel between solar systems there is no longer any need to do so.
I mean, in this age we are still discovering super strange weird stuff on the atomic/proton/electron/quark scale, so maybe we need a lot of more time to discover other super strange weird stuff on the galactic/universe level as well.
Also due to the continuing expansion of the universe, that latter probability will get more infinitesimal for any given pocket of life as time goes on and more & more of what has happens in the universe “escapes” their light-cone.
As a teenager I read Heinlein's 'Goldfish Bowl' [1] and it was the best explanation apart from the one from Stanislaw Lem I had heard for the lack of aliens. Namely that: you can't 'see' them because they're just too different.
Heinlein doesn't even make it clear if the higher intelligence in his short story are aliens or from Earth.
I think Lem's explanation (don't remember in which book/short story of his) was that the window where a civilisation is not advanced enough to learn something from aliens but not too advanced to care is just sth. like 3000 years.
And therefore, even if this level of development was reached by two proximate civilizations, e.g. even on neighboring planets in the same solar system -- if those windows didn't overlap, chances for communication happening would essentially be zero.
I think 'we're first' is unlikely, but the universe is so unimaginably large that we could well be first in the little bubble we can readily observe. Alternatively, another civilization has come and gone, and we've yet to spot it's remnants.
I don't buy the whole idea of 'we just can't see them'. We're very good at detecting signal from our physical world, and any advanced civilization is going to be noticeable as they start harvesting the power of nearby suns.
Maybe you're right though, maybe 'dark matter' is the mass of other multiverses and gravity is the only force that bleeds through.
I also think some version of 2 is overwhelmingly likely.
In particular, I have always found the core premises of SETI surveys profoundly naive in terms of necessary preconditions for it to be meaningful.
"If your only tool is a giant radio telescope, you look for radio signals." And in specific you look in bands that fit various preconditions of your technology; and then you look for signals which are loosely comparable to the ones we humans used nearly a century ago.
The folly of belief that such surveys are likely to uncover unobfuscated communications by some other civilization was truly driven home to me reading here on HN in the last year or two a deep dive into an iPhone exploit that relied on exploiting some issues with its discovery protocols for other devices in the phone's vicinity. The specifics of its multiplexing and frequency hopping and duty cycling across various tasks were hard enough to follow when the priors of the stack and hardware are all very well known.
The only signal SETI is liable to see is the equivalent of someone blowing an air horn in a stadium explicitly to be heard. Maybe someone does that. Maybe they find the forest dark enough to not...
The more interesting survey IMO is to look carefully for Dyson-sphere style dimming...
Every time you see someone saying Earth is rare in some way, or that the Great Filter is behind us, or that life is plentiful, but far away (grabby aliens being one of those), those are all the same argument, and the exact same argument as your #1.
It is still missing any justification for what is so rare about it. (Not that those arguments are any hard to make; instead the main question here is which of them is the correct one.)
Your argument #2 (that's the exact same as the zoo hypothesis) needs an extremely good reason for no alien at all trying to kill us and take Earth. And we currently lack any good reason.
If the Great Filter is behind us, I like mitochondria as a candidate; from what we know of Earth, it took over a billion years to happen, appears to have happened just once, and all complex life has it.
> "Your argument #2 (that's the exact same as the zoo hypothesis) needs an extremely good reason for no alien at all trying to kill us and take Earth. And we currently lack any good reason."
Maybe life supporting planets are abundant and there's no reason to risk a conflict with us?
We've certainly been detecting a lot of them anyhow.
It could be equivalent to me going to Africa to fight a lion for its den instead of just renting an apartment.
Given that our planet is younger than most planets in our galaxy, and IIRC younger than the average of all the planets which will be in our galaxy, we are the first if and only if we are the only intelligent life which will ever form in our galaxy.
I'd strongly disagree with the notion of "we are only 14B years into a many-trillion-year stretch" - we're at or past the midpoint, half or more of all the possible potential-life-forming-events in our galaxy have already occurred.
>we're at or past the midpoint, half or more of all the possible potential-life-forming-events in our galaxy have already occurred
Caveat: for life that resembles life on Earth.
Admittedly that's the only kind of life we're certain exists, but more or less alien forms of life seem to be at least theoretically possible. (Which gets into whether we'd even recognize each other as life.)
My favourite resolution is that "intelligence" is a concept created by humans that only humans and species evolutionarily close to humans have. It should be called "human intelligence".
The Fermi paradox doesn't work because we have roughly the same chance of finding a human-intelligent alien as we have to find a Swedish-speaking alien. For all I know the planet Neptune is actually alive and intelligent in a way we cannot comprehend.
> The Fermi paradox doesn't work because we have roughly the same chance of finding a human-intelligent alien as we have to find a Swedish-speaking alien.
My favorite solution is very simple: We're overestimating our ability to detect extraterrestrial live. It might be common and look similar to us. They might even use radio signals. But until somebody demonstrates that you can detect stray telecommunications signals over lightyears I find it hard to believe. I also think it is going to be hard to detect the chemical signature of life e.g. via spectroscopy, if you can't even image the planet next to it's overshining star.
Second, and somewhat sobering part: I also think it is practically impossible to do interstellar journeys. You can imagine scaling up existing tech to do so. But I think at some point the complexity and cost (in terms of resources, not money) would diverge. As an analogy, you can build a small robot, but if you try to scale it up to a mech it will not work in reality. Too heavy to move, yet to flimsy to stand.
I'm not convinced by refutations of #2 that point out that we humans have developed technologies that extend our senses, eg. we can now detect neutrinos, gravity waves, microwaves, what-have-you.
While these are extensions of the senses we have, we still are evolved to understand an environment that is an infinitely narrow slice of all possible environments in the universe, and Earth life's approach is an infinitely narrow slice of all possible ways of perceiving and surviving an underlying reality that is vastly unknowable.
As we look into a Universe (or even look around ourselves here on Earth) with our sense extenders, we are still bound by the limitations of our cognition and perception.
1 is not true. You are actually experiencing dartboard paradox. The probability of the dart hitting one particular point is nearly zero. Yet some point has to be hit by the dart.
In the same way, even though someone has to be the first, that does not change the probability of us being the first (which is very unlikely by most estimates of the probability distribution)
In my understanding the only hard assumption in the grabby aliens hypothesis is that there is a chance of a civilization becoming "grabby" by which they mean it sprouts new civilizations in neighboring solar systems. Everything else is just necessary simplification. It even accounts for civilizations not becoming grabby.
And the grabby hypothesis predicts we are quite early.
The problem with the analogy is assuming that humans are the only living things for the ants to find! (An ironically human-centric error in an attempt to expose human-centric thinking) The analogy would be more accurate if the two ants had scanned everything in a one-mile radius and found zero other insects anywhere, which would be... a little curious...
Space is really big, and radio emissions are really weak. The strongest isotropic radio emissions from Earth (e.g. high power TV broadcasts) would be indistinguishable from background radiation at only a light year or two away. One study [0] suggests that directed radio emissions an order of magnitude more powerful than the most powerful radio emitters on Earth could be detectable at ~100 light years (1/1000 the diameter of the Milky Way), but our detector would have to be perfectly aligned with the transmission at the exact time it reaches Earth.
This still doesn't explain why we don't see evidence of life though, just why finding evidence of alien life via eavesdropping on extra-terrestrial radio emissions would be unlikely.
If the galaxy really was full of intelligent life it's likely we would see evidence of it in some form. For one, it seems probable that any expansionist intelligent life in our galaxy would eventually notice our Earth is likely to be an interesting place. Even if they didn't visit us personally it seems strange they wouldn't send a simple probe or try to make their presence known to us in one way or another.
But to your point, perhaps intelligent life is quite common, it's just rare for it to be expansionist - at least beyond it's own solar system. In which case yeah, there could be a lot of Earth-like civilisations out there, but we'd be unlikely to see evidence for them.
> This still doesn't explain why we don't see evidence of life though...
It is an adequately plausible explanation of why we haven't yet seen evidence of life elsewhere. To argue against it seems to require one or more question-begging premises.
Interstellar meetings are bound to happen first with a large developmental gap.
Applicable here is obviously us being the Cavedwellers, Sumerians, Azteks, Egyptians, whathaveyou.
What happens? Astronauts appear as effectively gods, being literally superior beyond comprehension in every aspect. Religions sprout, sacrifices are made, wars fought...all because you thoughtlessly wanted to be nice and sey 'hello'.
Self-knowledge is a prerequisite to fruitful, non-destructive communication between civilizations. The ability to comprehend the scientific technicalities is likewise necessary and we are just on the brink of that.
There are (many) other requirements. Importantly, you have to be able to imagine a superior entity other than as playing the role of your "master".
Sending a probe takes very, very long, and is just as expensive, so it seems even less likely to arrive than a radio signal. And we might not even notice either one if it gets here.
There's a growing body of evidence that Earth has already been visited numerous times by something other than humans.
Certain classes of UAPs demonstrate flight characteristics that are not possible given our current understanding of gravity and aerodynamics.
Dozens of credible eye witnesses from multiple countries; fighter pilots, commercial pilots, nuclear physicists, and high ranking government officials.
Source "In Plain Sight", US Navy fighter pilots David Fravor and Ryan Graves, etc.
People are quick to dismiss these stories as hoaxes or bad memory, but scientific discovery almost always starts with an unusual or unexplained observation.
Uranium was discovered in 1785 and ionizing radiation wasn't discovered for another 110 years in 1895. True scientific understanding of new observations takes quite a while.
We noticed GRB221009A despite it being 2.4billion light years away. Makes you wonder if someone took the opportunity to encode data in it.
Edit: Another reason to analyze it is that existential threats are a universal language. Any sufficiently advanced civilization must pay attention to possible threats, so that it can avert them. It then follows that if you want to get the attention of another civilization about which you know almost nothing, threatening them is a viable method. Of course you don't want to overdo it, lest they actually hunt you down. A blast of high energy (but non-lethal) radiation will draw attention without making anyone panic. Intelligent civilization within a huge radius will certainly be tuning in.
There's something I intuitively dislike about the early human hypothesis to the Fermi paradox. It seems too much like geocentric Earth hypothesis or the long line of hypotheses which suggest us humans are special in some way. We rarely are.
I find the Fermi paradox fascinating though because non of the proposed answers satisfy me. These days I tend to think it's likely there are few compounding factors instead of any one single factor. I quite like the idea that intelligent life probably is fairly rare (so maybe we are quite early) and that the intelligent life that does evolve is fairly likely to either destroy itself or to simply lose interest in the analogue world with time. Personally I think if there is intelligent life out there most of it is probably living in digital worlds because why use energy exploring and explaining this universe when you can just create your own?
On the less likely but interesting side of things I also wonder if it suggests simulation sometimes. If everything points to us being quite uncommon then at some point it becomes reasonable to ask if it's even a question of probability but instead perhaps one of intention. If you see 10 dice on a table and all are showing a 6 on the face, you probably wouldn't think, "oh, how unlikely", but instead assume it was intended. But then again simulation theory is a good answer to all hard questions so I'm not that keen on it either. I just think it's most compelling in the context of the Fermi paradox and our seemingly fine-tuned universe.
I believe that the earth centric and human centric view is the problem with the Fermi paradox. Why do we assume that a civilization more advanced than us would have desires towards colonization and contact with lesser lifeforms?
It would be like an ant colony assuming there are no more advanced lifeforms because a more advanced lifeform would have destroyed their colony or contacted them via pheromones
With the "grabby aliens" there is only the assumption that a portion of civilizations become grabby. We don't have good reasons to believe that portion to be zero. But even a very small chance leads to all the other predictions, like that we are early and so on.
It's also not so much about active contact than that you could observe technological signatures from a certain distance.
I don't think the fermi paradox assumes that. Aliens don't have to want to be seen for us to see them. All it takes is one civilization failing to hide for us to see aliens, so the question then is "why has every single intelligent life form dedicated so many resources toward effectively hiding" or "if they're not doing that why haven't we seen them"
I don't like ant colony analogies because I think there is a meaningful difference between a life-form entirely unable to communicate high-level abstract thoughts and those that are - even if it's relatively simple.
For example we view apes as "lesser lifeforms" to ourselves but we still try to communicate with them, and they communicate back to some degree. Or a more extreme example would be dogs - we communicate with them all the time even if they don't have anything that interesting to say back to us.
I'd also argue we still take significant interest in ants despite the fact they're unaware of us. And if we thought we could say hi to ants via pheromones we almost certainly would. The mere fact we keep records of all the species we find on Earth and try to understand them in great detail despite them being much less intelligent then ourselves I think suggests aliens would probably at least have some interest in us, even if we're not that interesting.
And even with ants it's clear we have a lot to learn from them. Ant colony optimisation algorithms wouldn't exist if we didn't take an interest in ants, for example.
I did some thinking on the Fermi paradox some time ago. I arrived at the following theory(I am probably not the first one), using these assumptions:
- speed of light(causality) cannot be practically broken / cheated
- current stasis technology theorizing is over-optimistic
- brain-computer interfaces are possible
- computational power/speed will continue to increase
I am assuming that some time in the future, a human will be able to process information 1000x faster than one is able to today, using brain augmentations anr/or brain-computer chip interfaces. This does effectively slow down our perception of time by a factor of 1000x (simplifying and ignoring inefficiencies of course). So if I lived in that time, and got diagnosed with a terminal disease and 1 year to live, I would spend my last year in VR, perceiving it as 1000 years.
Continuing that thought, I might spend my entire life inside VR, living a thousand lifetimes before my biological body gives in.
The galaxy might be full of life, but at a certain point in their development, they turn inwards, because it gives much bigger rewards (the first instinct of any life form is to survive for as long as possible).
The biggest flaw I find in my theory is the assumption they couldn't just VR on spaceships while they're exploring the galaxy anyway.
The biggest flaw in this and similar theories is that it requires 100.000000000...% of beings to decide this is the way to go. Not a single being or entity (corporation, or something more exotic) ever decides, over the whole life time of the civilization that, hey, if we send a space ship over there we can have an entire solar system of our own to play with. Including possibly entities constructed for the explicit purpose of doing that by other entities who do not themselves care. One must also consider that not every being is necessarily limited by our life span too; star travel is effectively impossible for us in our state, but if we casually lived 10 million years and could propagate that in space ships star travel would merely be a massive inconvenience. Plus civilizations can in principle live in denser areas.
This is a general problem across most kneejerk answers, like "humans just suck so hard that there's no chance that they'll make it out before they kill themselves". Possibly true. But to be an answer to the Fermi paradox, it must be the case that all civilizations have that problem, including ones based on insects with strong hierarchies and ones based on super-hippies and slower ones and faster ones and all the ones.
It isn't enough to explain 99% of the problem away, especially if it's done with explanations that aren't even necessarily that good in the first place. You need 100.00%, with several significant digits. (I used more in my first paragraph because that was per being, this one is per civilization.)
I think you can safely leave it at 99% or so if you assume a maximum "radius of effect" that a civilization could have over X billion years. If the limit of a civilization is, for example, on the order if 100 light years, then there could be several such civilizations in our galaxy without us noticing it.
Brain computer interfaces could be 1000 times faster than skin/eye/ear to brain but the speed of the brain is going to stay the same, right? No accelerated time, at least not much of it. Example: if you accelerate audio 1000 times you won't be able to understand it. Two times? OK, with some training. 1000 times faster video? It's a blur. 10 times? Maybe. Your reaction times to give inputs? The usual tens or hundreds of seconds.
I have a tangential thought similar regarding simulation theory, that perhaps there is no other aliens because we're the only one 'simulated', and the purpose of said simulation is because in order to train AI (we're already seeing this) an AI needs a physical body, of course a simulated physical body could probably suffice, it needs to be nurtured by a parent, and experience the world with all it's senses/sensors.
Perhaps we're just ai-babies, and when we're done here we move on to being ai-butlers to rich people in the 'real' world.
If we're a simulation then there's no reason why alien life couldn't also be simulated unless there's a specific point to our simulation that the presence of alien life would interfere with. If there's a point to the simulation we're all experiencing I have no fucking clue what it is.
I suppose if we take the philosophical position of Bayesian statistics, where even one sample is sufficient basis for estimating results from some sane priori model, I would say this topic is within reach of some sane postulation. Some factors we can take into account:
1. Life can evolve into us. Therefore life on other planets has p>0 to evolve agglomerations of matter we would call "alien civilization"
2. Evolution seems to be driven through external constraints, and seems to generate similar structures to solve similar problems. Hence it's not insane to postulate organelles and their function are a particular energy minima to a complex set of constraints - ie. evolution on any earth like planet might reach similar patterns as earth life.
3. Neurological function seems to be driven by laws of mathematical dynamics up to a point - if it's math, we will see it everywhere in the universe. What sort of math - I suppose nobody completely understands yet.
4. I use the above to postulate that familiar modes of existence and familiar neurological function can emerge anywhere in the universe
5. If a species is to survive, it needs to have innate drive to do so. Unless species innate drive to survive perishes, an intelligent species will realize it's chances of survival are better if it is not limited to one planet. Then, one solar system and so on. Therefore we can postulate a "natural tendency" to start interstellar expansion.
6. Humans have already launched an interstellar space craft (Voyager). Therefore p>0 that life can evolve to develop vehicles that exceeds the escape velocity form their home star
Or something like that. The thing is, I don't understand the problem well enough to know if it's impossible to probe by statistics or not. I just know I'm not smart enough to solve the matter - when I did a course on Bayesian statistics the thing that left me astounded time and again was that one could create sane and accurate models from incredibly thin amount of data if one just had a good enough grasp of some of the factors at play.
> I suppose if we take the philosophical position of Bayesian statistics, where even one sample is sufficient basis for estimating results from some sane priori model...
Some care should be taken to see that this principle is not being used to excuse just making things up. Bayesian statistics is rational but not magical, and it cannot create information out of nothing.
In practice, this comes down to the question of whether the model is plausible, accurate, complete and constrained enough to deliver an answer that is informative about the external world, as opposed to the choices made in modeling. Something more than reasons to believe various probabilities are non-zero is needed.
I feel that, in your final paragraph, you are grappling with this issue.
> If a species is to survive, it needs to have innate drive to do so....
It's worth pointing out, that's not how natural selection works. NS would be: If a species has an innate drive to survive, it will do so. Yes, subtle. But essential.
That aside, how would you account for an asteroid strike?
> 1. Life can evolve into us. Therefore life on other planets has p>0 to evolve agglomerations of matter we would call "alien civilization"
In any universe that we can observe, we must exist. That strips away any useful a priori probability estimations about how likely we were to come into existence. p ~= 0 is still p > 0. There could have been a trillion trillion trillion trillion universes before this one where no life evolved that we would never know about because we were not around to observe them. And there could be a trillion trillion trillion universes after this one in which no life arises.
For 1, Life has more chance to evolve in milliona of other species that dont o serve space, master fire or launch rockets. pretty bad odds once you look around you. plus we have been graced by having fairly mild cosmic conditions for a long time. other planets may not be so lucky
Agreed. This is irresponsible science communication --- and at a time when public understanding of and trust in science has been dropping significantly.
To me the Fermi paradox is easily explained by the speed of light being a hard limit on how fast something can go and the fact that space is absolutely enormous. Every expectation of multi planet civilizations simply hand waves away physics. How would they move between stars? "You know, alien stuff. They'll figure it out."
There are also unstated economic assumptions that don't make a lot of sense. Why would they leave their planet anyway? A civilization wealthy and advanced enough to consider traveling to other planets probably does not have a population big enough to support the kind of large scale emigration needed to set up big colonies. Wealthy societies have fewer children. Then of course there is the question of why would you ever leave a planet with such advanced technology and apparent wealth? I would much rather live in any city on earth than a colony on the moon or Mars. How long would it take for those colonies to be as attractive a living space as the place we have right now?
I think your first point ignores one of the fundamental insights of the Fermi Paradox, which is that while space on an astronomical scale is massive, so is time. The milky way galaxy is ~100,000 light years across. So traveling at 1% of the speed of light, you could go end to end in 10,000,000 years. That sounds like a long time, but it's really not.
The earth is ~4.5 billion years old. So we can say with certainty that it's possible (not guaranteed) to become a space faring race (although not a galaxy crossing one) in 4.54 billion years. If we tack the amount of time it takes to cross the whole galaxy end to end we get 4.55 billion years. The milky way galaxy is 13.61 billion years old. That means the galaxy had 9.06 billion years worth of chances to churn out a another planet that could have expanded across the galaxy from edge to edge and been here waiting when humans arrived on the scene. Planets with Earth like conditions are certainly rare but my, admittedly limited, understanding is that they're not "1 in 9.06 billion years" rare.
There are obviously other constraints here. I think your second point about wealthy technological races potentially stabilizing at zero population growth is totally reasonable. But I think the fact that space's apparent scale doesn't actually matter is the whole reason the Fermi Paradox was such an "ah-ha!" moment for many people. The reason it's a paradox is that, given all of our assumptions for variable values in the Drake Equation at the time, it really seemed like we should have met some aliens. The point was that if distance wasn't the hurdle we thought it was in the equation as currently defined, then we were either missing some relevant variables, or we had made some bad assumptions for the ones we had.
> wealthy technological races potentially stabilizing at zero population growth
It doesn't have to, in fact (relatively) endless population growth is the prime force to push even lazy non-curious fearful aliens out of their planet and sun. That and obvious unavoidable necessity of every sun eventually becoming killer of its own ecosystem, even if their planet would be super duper stable with all meteorites under total control.
The rest I agree with, even civilization having mere 100 million years of advantage on us would be able to properly colonize non-trivial part of milky way by now, we just have to abandon star trek/wars expectations of instant communication and travel which is fine. We humans are generally pretty bad at grasping true meaning of numbers when it comes to ie astronomy.
So traveling at 1% of the speed of light, you could go end to end in 10,000,000 years. That sounds like a long time, but it's really not.
Human have no way to survive that time period, no way to create a self contained environment that would survive that time period and no civilization that's lasted a fraction of that time. The increase of human technology hasn't correlated with stability so increases in our technology don't seem like arguments for our ability to act in a long and large scale, despite being implicitly taken as such by a lot of people.
Sure, in the geological time humans study ten million years isn't much but the claim that a living creature could act in the time period is purely speculative. Speculation is fine but the rhetoric of the "Fermi Paradox" is "why don't I see of things I have only wildly speculated about, there's something weird here", which is kind of problematic.
You don't need to hand wave physics away. von Neumann probes + a lot of time would give space faring civilizations ways to arrive at the furthest reaches of the galaxy, even with our current understanding of physics.
To me there’s an obvious counter to “the speed of light is too slow” and that’s reframing it as “we don’t live long enough” and since we as a society are trying to extend the length of our lives on a multitude of fronts from egocentric rich people to public health institutions, at the end of the day, people who can live longer tend to be healthier and socially productive longer than those who won’t live as long.
Effectively by working to conquer cancers and age related diseases/decline, and the general effort to “extend our lives”… we are making space slightly smaller for our future selves once our propulsion technology advances to the point we can achieve decent percentages of the speed of light… which there are no real technical barriers against. From solar sails to muon fusion to all sorts of other interesting technology we have yet to develop, we may not be able to break a warp barrier and go faster than light… but if we live longer, say 10 times longer, the. Suddenly 5 years shipboard time travelling to another star system doesn’t seem so bad. 5 years in a millennium of years is equivalent to a 6 month journey for someone who will live to 100.
The speed of light is a limiting factor, but most models I have seen of galactic civilizations take that into account, yet they project that interstellar expansion of a hypothetical civilization is possible.
There are other factors that are more likely to explain why we are apparently alone: civilizations might not last long enough that they would encounter us before dying out, or that they have not yet emerged. IOW we might be alone in time more than we are alone in space.
The premised of "Wealthy societies have fewer children." is wrong; correlation != causation.
You're posing these things as though they're axiomatic for all beings; as if these beings (which don't exist) would operate exactly as we do and not have their own cultures and ways of being distinct from our own here (of which are vastly different amongst people of other countries on Earth). It's a very narrow, human-centric view.
I agree with this. Given the vast time necessary to move (or even communicate) between stars, there is no social, political or economic reason to travel more than a few light years from your home planet. That's leaves science, religion and adventure as the only reasons to go really far out int space, and the cost of interstellar travel limits how many other planets can be visited for those reasons, even over tens of thousands of years.
Even if wormholes were real, and even if we could manipulate matter with negative energy density (which doesn't exist) on the order of many times the mass of the sun (which is needed for wormholes), constructing one that spans from A to B would take longer than light travels from A to B.
THANK YOU! It mystifies me how people manage to ignore this. Interstellar travel is going to be enormously difficult. Maybe just too hard to overcome regardless of technology level.
The Fermi paradox is completely overhyped, especially if it really originated from a lunch discussion with Fermi, as Wikipedia claims. It's a random thought, not some deep question about the universe. The paradox supposedly reads: If life is ubiquitous, then why don't we see it?
But there is nothing to solve. The first conclusion should be that the assumption is simply false. We have no proof that life ubiquitous, so why hold on to it so dearly?
But even if we do, there are plenty of reasonable and plausible explanations as to why we don't see alien life. Just read the other comments.
In fact, there are so many possible explanations that the challenge becomes: which one is the correct one? However, a paradox this is not.
The paradox is that if we make seemingly reasonable assumptions/estimates about all the factors required for advanced aliens to occur, there should be many such civilizations - and if we observe that there aren't any, then it implies that some of these assumptions are very, very wrong.
However, since the initial Fermi discussion we have gathered some more evidence about the universe and these assumptions/estimates still seem reasonable, in some cases (e.g. the number of exoplanets) even larger than originally. So there is a contradiction, or paradox about that.
I challenge the idea that all the assumptions hidden in the claim that life is ubiquitous are seemingly reasonable. For instance, we don't have the faintest idea of how likely it is that eukaryotic life evolves from prokaryotes or if prokaryotes can themselves become complex life forms. Next, we don't know the likelihood of complex life becoming intelligent. It's not like this is some natural goal of evolution, at least as far as we know. It may have been an extremely rare accident here on earth.
There are many more such assumptions, some of which Fermi could not have known about. But we shouldn't ignore all the progress we have made since then.
The paradox assumes "advanced aliens" having abilities we've never observed and which are impossible given current human technologies. These aliens have been imagined by essentially linearly extrapolating human technological progress and, European expansion across the Earth. Humans have explored the solar system and it's becoming clear to most people that off-earth settlements are unlikely to in the foreseeable future (despite certain people's claims). Colonizing near-space, if it happens, won't be like colonizing earth. Moreover, our current exponential increase in resource usage seems more like to destroy our species than to get us to space - if we fix that, the perceived need to get to get to space may much less once technology reaches the point it would allow us to do so.
Basically asking "why can't we see the interstellar empires?". Well, maybe these don't exist even if many earth-like societies exist. Maybe "colonizing" other stars is uninteresting to any society that reach level where it would be possible. Maybe there really are hard limits to such endeavors or maybe we're alone at the moment (the limited time in the universe is a factor. Life on earth took a significant fraction of the universe' lifetime to develop and the earlier universe might have been life hostile).
The unreasonable assumption is that aliens with hundreds of millions of years of additional development, would "colonize" planets like organic creatures and fly around like Star Trek.
It's entirely unreasonable to assume that we would be able to see aliens at all nor that they'd have any interest in US.
All science is accomplished by doing the exact opposite of the scientific method, which you’re essentially appealing to here. The scientific method isn’t how science is created, it’s how it’s finalized. In some way the scientific method part is the most important but least interesting part of proving a theory. Having a theory doesn’t mean the theory is wrong, it just means you can’t yet prove it is wrong. Any good theory has a very strong intuition to back it, otherwise why investigate it with the scientific method? A good theory should have some basis that’s logically convincing. You can definitely hype your theory while you prove it. That’s how you get other scientists to know of your theory and collaborate. A lot of scientific papers are doing exactly that - peddling an unproven theory by providing a proven step towards that ultimate theory. My feeling is the “life must exist” theory is probably right.
The problem for proving will be materially improving the ability to move mass and information in sufficient quantities and at sufficient rates to have any chance of proving anything one way or the other. But in order to prove the theory you need only one instance if it exists and we can make reasoned guesses about life we understand to see if there’s life like us as an optimization. That seems like a good advantage for proving life exists.
The disproof of life in the universe is even harder - you essentially need to comb everywhere and everything for patterns that aren’t explained by the local environment to disprove. I think it’s unlikely the theory will be disproven.
The longer we go without positive proof though the more likely we can not prove it but can assume life doesn’t exist outside this planet. But we haven’t gone very far for very long in the scale of human history, and given the acceleration of advancement over the last 500 years I don’t think it’s fair to say we’ve explored the space of the problem sufficient to assume life doesn’t exist.
And if it does exist, they likely have laser sharks and antimatter bombs. That’s why the Fermi paradox is so hyped.
To your first point, assuming alien life is not ubiquitous would be an equally thought provoking claim. The Fermi paradox asks “are we alone?” while yours claims “we are alone.”
My favorite solution to the Fermi Paradox is that star-shaped gravity wells are difficult neighborhoods for anything that needs to exchange huge amounts of data. Think about it: electromagnetic data-beans degrade with distance, so one must use relays. Relays in a gravity well must keep moving in orbits. And, well, stars are noisy and hot. With sufficient technology, a civilization is more interested in reliable data-transmissions and compute, which can be generally easier to achieve in interstellar space (which also happens to have enough "cold" matter in the form of wandering planets and planetoids).
There can be a huge number of civilizations gravitating around a star, just as we do. But any bigger civilization, bigger than their mother star, may soon find the interstellar space more comfy and remain there, beaming directional messages (and consciousness units, a.k.a souls) between cold outposts in interstellar space.
It's also quite easy to space travel outside of gravity well. Just take any piece of ice, drill yourself inside it and use thick ice walls as shelter. Mount some engines. If you're used to living in such environment you can be having a normal life while going around in it. Fusion as power source, likely.
Earth civilization is wondering why it can't see or hear anyone while almost literally living inside a beacon.
Fusion, probably. They have to find enough fuel in interstellar space, but theoretically it's possible.
The bigger question is why you would want to exist in an entirely artificial environment far from any star, even if it makes information interchange and computation more efficient.
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1 - Given that we are only 14B years into a many-trillion-year stretch, our existence now is so unlikely that it's possible that we actually are the first. Something has to be first.
2 - Aliens are everywhere, but we cannot perceive them for reasons we would find disturbing. Largely, for the same sort of reasons that cave fish cannot see light or that most species are apparently unaware of humans in their environment. Essentially, that there is no evolutionary reason for humans to perceive them.
As for grabby aliens... meh. I don't find it convincing as a resolution. It contains too many unexamined assumptions, quite like the simulation theory.
I don't really find it disturbing, though. Our "best practice" to interact with other species is to try to leave them alone and watch them enjoy and live in their habitat. Makes sense that's what we're doing for the alien overlords, and I'm okay with that. Assuming aliens are around somewhere and we're using our own planet to reason by analogy, the only other two alternatives are they're going to subjugate/destroy us or they're going to eat us. Those alternatives are not so fun.
I find it interesting that so many humans assume that since we can chat with one another, aliens somehow are supposed to show up and chat with us. It's all about us. If such a thing happened, the history of massively-different cultures interacting on Earth is not a positive one.
Given the choices, I'm good.
We do have terrestrial aliens here on Earth and we are trying to chat with them. Dolphins, Gorillas, Chimps, Bonobos, Crows, Killer Whales... there is evidence for all of these species having varying degrees of language, culture, problem solving capabilities. Some of them, like Dolphins, sure seem damned close to our own capabilities with likely fully formed languages. We've been trying to decipher their language for 50 years with almost no success. With many of these species we've figured out pretty rudimentary and simplistic communication modes, but they clearly have much more complex communication structures among themselves and we've come nowhere close to deciphering them.
That alone tells you how difficult it's going to be to learn to talk with extraterrestrial aliens. Even our near cousins, we struggle to communicate with.
If we're examining our behavior as an analogy for the ET's however, it would suggest that either no one's around, or those who are around are so advanced that they don't think we're worth the effort to communicate with. Because we're definitely trying to communicate with the species we're aware of that we think have language.
Of course, many of the species on that list were only added relatively recently (Crows, for example).
And even if we're not in a "dark forest", keeping quiet is generally good social hygiene and tends to correlate with maturity. Which may be a side-effect of #2.
Given the sheer size of the universe, and the absolutely massive costs of interstellar travel, I have no idea why any alien civilization capable of visiting us would have hostile intent. Life is rare. Elements, even the rarest, are exceedingly common.
The thought that an advanced alien civilization would cross thousands of light years of distance to subjugate or destroy some naked apes is hilarious to me.
Resolving the Fermi paradox by appealing to hypothetical aliens who are too high for us to perceive just feels like "aliens-of-the-gaps". The number of species on Earth with human intelligence (and quantity of such individuals) is orders of magnitude less than the number with ant intelligence. Aliens more advanced than us should similarly be that much less common than us. If humanity is not special, other aliens who are more equivalent to us are still missing.
Is intelligence necessarily organic matter based? Maybe not. Maybe somewhere in the universe a spontaneous self-replicating turing machine appeared. Maybe there is life on the event horizon of a black hole, or maybe a hot type of intelligence lives inside a star.
I think we can make all kinds of wild assumptions.
That’s not a very good analogy though. The ants’ answer would be “maybe across the ocean”. And since the ants lack any tech to check or be checked by other ants that would be the end of it. It’s not naivety. If there were other ants not visible to the island, they would be fundamentally underdiscoverable.
We can detect neutrinos with advanced instruments. We've never had an evolutionary reason to do that.
There's really just no room for this explanation. Energy and mass are one and the same. If we can detect neutrinos, but not these intelligent aliens that are everywhere, it means that they don't occupy physical space, don't have mass (and therefore must move at C only), don't use energy, don't send signals to one another, don't accelerate or decelerate, aren't involved in chemical reactions, don't interact with any of the particles we do, don't perceive light, etc. etc. At that point, they basically don't exist in our universe.
It's not enough to say "but ants don't know we exist!" -- first of all, yes they do. Secondly, you're really saying that intelligent ants who formed an advanced society, had a scientific revolution, and built instruments capable of determining the number of moons on Jupiter, still would not know we exist. That is clearly ludicrous.
And this doesn't even solve the Fermi paradox! There's clearly plenty of "room" for aliens that are "somewhat similar" to us; that is, they actually are made of protons and neutrons, etc. Where are all those aliens?
We don't know what we don't know from physics, the arrogance of thinking we get it all was there numerous times and it was always a wrong emotion, we even realize it for our current theories. There may be quantum entanglement communication, higher dimensions, strings or basically anything your nor my mind can't even come up with right now. Just like cavemen simply couldn't come up with general relativity even if it was all happening right in front of their eyes.
"We can detect things we were not evolved to detect" is a non-sequitur, a true statement that does not refute the original speculation. Because we can detect some things we were not evolved to perceive, does not mean we can therefore perceive aliens.
It's a difficult concept to communicate. Empirically it's literally meaningless. Even the concept of meaningful vitiates discussion of this idea.
Everything we are is perception, pattern recognition, threat assessment, problem solving. That there might be something important in our environment that we are simply not built to respond to is far easier to reject outright than to consider. This is why it's my favorite resolution to the Fermi Paradox, because it is so challenging to consider.
Our cognition has evolved only slowly compared to our rapid technological advancement. Perception is not simply detection, but also cognition. Though we detect such previous unknowns as neutrinos and invisible electromagnetism and peculiarities of quantum physics, we think about them differently than that with which we are familiar only with expensive and difficult training, and even then it's arguable that we are modeling reality itself or modeling only our limited perception of reality.
In short, while we are impressed with our abilities to understand our reality, we are still constrained by our evolved cognition to think effectively only about living by hunting and gathering in Earth-like conditions.
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As for number two, it's hard to comprehend a response that is reasonable because our cognition may be part of the "disturbing reasons" right?
The theory I more and more think is probably right is that there is some major aspect of the universe that we get wrong. What is more likely, humans thinking they understand something when they don't or that no life form was able to spread amongst the stars in billions of years? I have plenty of lived examples of humans with false knowledge.
It's a sort of meta Drake equation. [Likelihood humans are not as wise as they think they are]*[rest of drake equation] and I think the drake equation, as stated, correctly leads to the term "Paradox" given the conventional understanding of science as communicated by scientists.
"the leap to exponential tool" - the current human leap to exponential resource consumption seems to be colliding with the limited and fragile structure of the earth (IE, CO2 pollution is pushing to catastrophic global warming). A fair number of decision makers seem to expect some tech fix to appear when every indication is it won't. My point is "getting to stars" would require technological progress in a situation where a species learns to curb an appetite for exponential growth, something human beings certainly haven't achieved.
I don't quite understand your logic here? The big barrier(s) doesn't seem to be tool use, but rather 1) the formation of life itself, and then 2) the move from single-celled organisms to multicellular organisms (this took 2 billion years on earth, so is clearly a very difficult step).
4 We are weird in that we want to expand like this, but others don't, similar to how chimps appear to be well able to express themselves in sign language, but appear to simply lack any urge to do so. Similar to your #2.
5 There simply isn't a compelling reason to expand galaxy-wide by the time you can. Reproduction must be stabilized in some way if mortality is taken out of the equation, which will probably happen earlier, a sufficiently advanced understanding of cosmology and physics might conclude there isn't any danger that can't be managed or that spreading out over a few lightyears wouldn't guard against sufficiently well. Getting rid of evolutionarily helpful urges that become a burden in a post-evolution world might be a filter by itself, so this is similar to your #2 in that they're different in a way we can't easily conceive.
6 Once you can make any existence you want happen (by some kind of unimaginably advanced VR) and have tech keep everyone safe and alive indefinitely, the actual universe might start to seem underwhelming. Better to live out the millennia in a perfectly convincing hedonistic metaverse. I could see that happen to us, come to think of it.
This is my thought. Without FTL travel you have to go the slow way. Probably much less than C thanks to the rocket equation. But in order to do this you need to build a spacecraft capable of surviving for centuries or longer with absolutely no outside support, not even solar power.
But if you can build that you have effectively unlimited space in your own solar system. Why bothering to travel to a different solar system at that point? Maybe if you have used up literally all of the resources in your current solar system, but that's a multi-billion year process. So you might only need to make the trip once or twice in the current age of the universe. But even that seems less likely than just developing really good recycling systems.
So the solution to the Fermi paradox is that by the time you have the tech to travel between solar systems there is no longer any need to do so.
I mean, in this age we are still discovering super strange weird stuff on the atomic/proton/electron/quark scale, so maybe we need a lot of more time to discover other super strange weird stuff on the galactic/universe level as well.
Due to the vast scale of the universe, the probability of other life existing rounds to 100%.
Due to the vast scale of the universe, the probability of finding other life rounds to 0%.
As a teenager I read Heinlein's 'Goldfish Bowl' [1] and it was the best explanation apart from the one from Stanislaw Lem I had heard for the lack of aliens. Namely that: you can't 'see' them because they're just too different.
Heinlein doesn't even make it clear if the higher intelligence in his short story are aliens or from Earth.
I think Lem's explanation (don't remember in which book/short story of his) was that the window where a civilisation is not advanced enough to learn something from aliens but not too advanced to care is just sth. like 3000 years.
And therefore, even if this level of development was reached by two proximate civilizations, e.g. even on neighboring planets in the same solar system -- if those windows didn't overlap, chances for communication happening would essentially be zero.
[1] https://en.m.wikipedia.org/wiki/Goldfish_Bowl
I don't buy the whole idea of 'we just can't see them'. We're very good at detecting signal from our physical world, and any advanced civilization is going to be noticeable as they start harvesting the power of nearby suns.
Maybe you're right though, maybe 'dark matter' is the mass of other multiverses and gravity is the only force that bleeds through.
In particular, I have always found the core premises of SETI surveys profoundly naive in terms of necessary preconditions for it to be meaningful.
"If your only tool is a giant radio telescope, you look for radio signals." And in specific you look in bands that fit various preconditions of your technology; and then you look for signals which are loosely comparable to the ones we humans used nearly a century ago.
The folly of belief that such surveys are likely to uncover unobfuscated communications by some other civilization was truly driven home to me reading here on HN in the last year or two a deep dive into an iPhone exploit that relied on exploiting some issues with its discovery protocols for other devices in the phone's vicinity. The specifics of its multiplexing and frequency hopping and duty cycling across various tasks were hard enough to follow when the priors of the stack and hardware are all very well known.
The only signal SETI is liable to see is the equivalent of someone blowing an air horn in a stadium explicitly to be heard. Maybe someone does that. Maybe they find the forest dark enough to not...
The more interesting survey IMO is to look carefully for Dyson-sphere style dimming...
It is still missing any justification for what is so rare about it. (Not that those arguments are any hard to make; instead the main question here is which of them is the correct one.)
Your argument #2 (that's the exact same as the zoo hypothesis) needs an extremely good reason for no alien at all trying to kill us and take Earth. And we currently lack any good reason.
Maybe life supporting planets are abundant and there's no reason to risk a conflict with us?
We've certainly been detecting a lot of them anyhow.
It could be equivalent to me going to Africa to fight a lion for its den instead of just renting an apartment.
I'd strongly disagree with the notion of "we are only 14B years into a many-trillion-year stretch" - we're at or past the midpoint, half or more of all the possible potential-life-forming-events in our galaxy have already occurred.
Caveat: for life that resembles life on Earth.
Admittedly that's the only kind of life we're certain exists, but more or less alien forms of life seem to be at least theoretically possible. (Which gets into whether we'd even recognize each other as life.)
The Fermi paradox doesn't work because we have roughly the same chance of finding a human-intelligent alien as we have to find a Swedish-speaking alien. For all I know the planet Neptune is actually alive and intelligent in a way we cannot comprehend.
This is great.
Second, and somewhat sobering part: I also think it is practically impossible to do interstellar journeys. You can imagine scaling up existing tech to do so. But I think at some point the complexity and cost (in terms of resources, not money) would diverge. As an analogy, you can build a small robot, but if you try to scale it up to a mech it will not work in reality. Too heavy to move, yet to flimsy to stand.
While these are extensions of the senses we have, we still are evolved to understand an environment that is an infinitely narrow slice of all possible environments in the universe, and Earth life's approach is an infinitely narrow slice of all possible ways of perceiving and surviving an underlying reality that is vastly unknowable.
As we look into a Universe (or even look around ourselves here on Earth) with our sense extenders, we are still bound by the limitations of our cognition and perception.
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In the same way, even though someone has to be the first, that does not change the probability of us being the first (which is very unlikely by most estimates of the probability distribution)
And the grabby hypothesis predicts we are quite early.
"Grabby aliens" asserts that we are early, like point 1.
https://arxiv.org/abs/2012.07902
I don't understand what you meant by this part. Matter to what?
[0] https://arxiv.org/pdf/astro-ph/0610377.pdf
If the galaxy really was full of intelligent life it's likely we would see evidence of it in some form. For one, it seems probable that any expansionist intelligent life in our galaxy would eventually notice our Earth is likely to be an interesting place. Even if they didn't visit us personally it seems strange they wouldn't send a simple probe or try to make their presence known to us in one way or another.
But to your point, perhaps intelligent life is quite common, it's just rare for it to be expansionist - at least beyond it's own solar system. In which case yeah, there could be a lot of Earth-like civilisations out there, but we'd be unlikely to see evidence for them.
If we detected something we thought was intelligent life, could we send a probe like you describe? Our nearest star is 4 light years away.
It is an adequately plausible explanation of why we haven't yet seen evidence of life elsewhere. To argue against it seems to require one or more question-begging premises.
What happens? Astronauts appear as effectively gods, being literally superior beyond comprehension in every aspect. Religions sprout, sacrifices are made, wars fought...all because you thoughtlessly wanted to be nice and sey 'hello'.
Self-knowledge is a prerequisite to fruitful, non-destructive communication between civilizations. The ability to comprehend the scientific technicalities is likewise necessary and we are just on the brink of that.
There are (many) other requirements. Importantly, you have to be able to imagine a superior entity other than as playing the role of your "master".
Alien behavior is likely to seem strange to humans.
It would be much more surprising if they did what we expected them to do.
Certain classes of UAPs demonstrate flight characteristics that are not possible given our current understanding of gravity and aerodynamics.
Dozens of credible eye witnesses from multiple countries; fighter pilots, commercial pilots, nuclear physicists, and high ranking government officials.
Source "In Plain Sight", US Navy fighter pilots David Fravor and Ryan Graves, etc.
People are quick to dismiss these stories as hoaxes or bad memory, but scientific discovery almost always starts with an unusual or unexplained observation.
Uranium was discovered in 1785 and ionizing radiation wasn't discovered for another 110 years in 1895. True scientific understanding of new observations takes quite a while.
Edit: Another reason to analyze it is that existential threats are a universal language. Any sufficiently advanced civilization must pay attention to possible threats, so that it can avert them. It then follows that if you want to get the attention of another civilization about which you know almost nothing, threatening them is a viable method. Of course you don't want to overdo it, lest they actually hunt you down. A blast of high energy (but non-lethal) radiation will draw attention without making anyone panic. Intelligent civilization within a huge radius will certainly be tuning in.
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I find the Fermi paradox fascinating though because non of the proposed answers satisfy me. These days I tend to think it's likely there are few compounding factors instead of any one single factor. I quite like the idea that intelligent life probably is fairly rare (so maybe we are quite early) and that the intelligent life that does evolve is fairly likely to either destroy itself or to simply lose interest in the analogue world with time. Personally I think if there is intelligent life out there most of it is probably living in digital worlds because why use energy exploring and explaining this universe when you can just create your own?
On the less likely but interesting side of things I also wonder if it suggests simulation sometimes. If everything points to us being quite uncommon then at some point it becomes reasonable to ask if it's even a question of probability but instead perhaps one of intention. If you see 10 dice on a table and all are showing a 6 on the face, you probably wouldn't think, "oh, how unlikely", but instead assume it was intended. But then again simulation theory is a good answer to all hard questions so I'm not that keen on it either. I just think it's most compelling in the context of the Fermi paradox and our seemingly fine-tuned universe.
It would be like an ant colony assuming there are no more advanced lifeforms because a more advanced lifeform would have destroyed their colony or contacted them via pheromones
It's also not so much about active contact than that you could observe technological signatures from a certain distance.
For example we view apes as "lesser lifeforms" to ourselves but we still try to communicate with them, and they communicate back to some degree. Or a more extreme example would be dogs - we communicate with them all the time even if they don't have anything that interesting to say back to us.
I'd also argue we still take significant interest in ants despite the fact they're unaware of us. And if we thought we could say hi to ants via pheromones we almost certainly would. The mere fact we keep records of all the species we find on Earth and try to understand them in great detail despite them being much less intelligent then ourselves I think suggests aliens would probably at least have some interest in us, even if we're not that interesting.
And even with ants it's clear we have a lot to learn from them. Ant colony optimisation algorithms wouldn't exist if we didn't take an interest in ants, for example.
- speed of light(causality) cannot be practically broken / cheated
- current stasis technology theorizing is over-optimistic
- brain-computer interfaces are possible
- computational power/speed will continue to increase
I am assuming that some time in the future, a human will be able to process information 1000x faster than one is able to today, using brain augmentations anr/or brain-computer chip interfaces. This does effectively slow down our perception of time by a factor of 1000x (simplifying and ignoring inefficiencies of course). So if I lived in that time, and got diagnosed with a terminal disease and 1 year to live, I would spend my last year in VR, perceiving it as 1000 years.
Continuing that thought, I might spend my entire life inside VR, living a thousand lifetimes before my biological body gives in.
The galaxy might be full of life, but at a certain point in their development, they turn inwards, because it gives much bigger rewards (the first instinct of any life form is to survive for as long as possible).
The biggest flaw I find in my theory is the assumption they couldn't just VR on spaceships while they're exploring the galaxy anyway.
This is a general problem across most kneejerk answers, like "humans just suck so hard that there's no chance that they'll make it out before they kill themselves". Possibly true. But to be an answer to the Fermi paradox, it must be the case that all civilizations have that problem, including ones based on insects with strong hierarchies and ones based on super-hippies and slower ones and faster ones and all the ones.
It isn't enough to explain 99% of the problem away, especially if it's done with explanations that aren't even necessarily that good in the first place. You need 100.00%, with several significant digits. (I used more in my first paragraph because that was per being, this one is per civilization.)
Sounds a lot like the Bobs in the Bobiverse
Perhaps we're just ai-babies, and when we're done here we move on to being ai-butlers to rich people in the 'real' world.
> "Advanced aliens really are out there, and we have enough data to say roughly where they are in space and time, and when we will see or meet them."
is not proven. It's just some really smart people attempting to reach a conclusion I'm not sure is within reach. We just don't know.
1. Life can evolve into us. Therefore life on other planets has p>0 to evolve agglomerations of matter we would call "alien civilization"
2. Evolution seems to be driven through external constraints, and seems to generate similar structures to solve similar problems. Hence it's not insane to postulate organelles and their function are a particular energy minima to a complex set of constraints - ie. evolution on any earth like planet might reach similar patterns as earth life.
3. Neurological function seems to be driven by laws of mathematical dynamics up to a point - if it's math, we will see it everywhere in the universe. What sort of math - I suppose nobody completely understands yet.
4. I use the above to postulate that familiar modes of existence and familiar neurological function can emerge anywhere in the universe
5. If a species is to survive, it needs to have innate drive to do so. Unless species innate drive to survive perishes, an intelligent species will realize it's chances of survival are better if it is not limited to one planet. Then, one solar system and so on. Therefore we can postulate a "natural tendency" to start interstellar expansion.
6. Humans have already launched an interstellar space craft (Voyager). Therefore p>0 that life can evolve to develop vehicles that exceeds the escape velocity form their home star
Or something like that. The thing is, I don't understand the problem well enough to know if it's impossible to probe by statistics or not. I just know I'm not smart enough to solve the matter - when I did a course on Bayesian statistics the thing that left me astounded time and again was that one could create sane and accurate models from incredibly thin amount of data if one just had a good enough grasp of some of the factors at play.
Some care should be taken to see that this principle is not being used to excuse just making things up. Bayesian statistics is rational but not magical, and it cannot create information out of nothing.
In practice, this comes down to the question of whether the model is plausible, accurate, complete and constrained enough to deliver an answer that is informative about the external world, as opposed to the choices made in modeling. Something more than reasons to believe various probabilities are non-zero is needed.
I feel that, in your final paragraph, you are grappling with this issue.
https://en.wikipedia.org/wiki/Fermi_paradox#Drake_equation
It's worth pointing out, that's not how natural selection works. NS would be: If a species has an innate drive to survive, it will do so. Yes, subtle. But essential.
That aside, how would you account for an asteroid strike?
> 1. Life can evolve into us. Therefore life on other planets has p>0 to evolve agglomerations of matter we would call "alien civilization"
In any universe that we can observe, we must exist. That strips away any useful a priori probability estimations about how likely we were to come into existence. p ~= 0 is still p > 0. There could have been a trillion trillion trillion trillion universes before this one where no life evolved that we would never know about because we were not around to observe them. And there could be a trillion trillion trillion universes after this one in which no life arises.
There are also unstated economic assumptions that don't make a lot of sense. Why would they leave their planet anyway? A civilization wealthy and advanced enough to consider traveling to other planets probably does not have a population big enough to support the kind of large scale emigration needed to set up big colonies. Wealthy societies have fewer children. Then of course there is the question of why would you ever leave a planet with such advanced technology and apparent wealth? I would much rather live in any city on earth than a colony on the moon or Mars. How long would it take for those colonies to be as attractive a living space as the place we have right now?
The earth is ~4.5 billion years old. So we can say with certainty that it's possible (not guaranteed) to become a space faring race (although not a galaxy crossing one) in 4.54 billion years. If we tack the amount of time it takes to cross the whole galaxy end to end we get 4.55 billion years. The milky way galaxy is 13.61 billion years old. That means the galaxy had 9.06 billion years worth of chances to churn out a another planet that could have expanded across the galaxy from edge to edge and been here waiting when humans arrived on the scene. Planets with Earth like conditions are certainly rare but my, admittedly limited, understanding is that they're not "1 in 9.06 billion years" rare.
There are obviously other constraints here. I think your second point about wealthy technological races potentially stabilizing at zero population growth is totally reasonable. But I think the fact that space's apparent scale doesn't actually matter is the whole reason the Fermi Paradox was such an "ah-ha!" moment for many people. The reason it's a paradox is that, given all of our assumptions for variable values in the Drake Equation at the time, it really seemed like we should have met some aliens. The point was that if distance wasn't the hurdle we thought it was in the equation as currently defined, then we were either missing some relevant variables, or we had made some bad assumptions for the ones we had.
It doesn't have to, in fact (relatively) endless population growth is the prime force to push even lazy non-curious fearful aliens out of their planet and sun. That and obvious unavoidable necessity of every sun eventually becoming killer of its own ecosystem, even if their planet would be super duper stable with all meteorites under total control.
The rest I agree with, even civilization having mere 100 million years of advantage on us would be able to properly colonize non-trivial part of milky way by now, we just have to abandon star trek/wars expectations of instant communication and travel which is fine. We humans are generally pretty bad at grasping true meaning of numbers when it comes to ie astronomy.
Human have no way to survive that time period, no way to create a self contained environment that would survive that time period and no civilization that's lasted a fraction of that time. The increase of human technology hasn't correlated with stability so increases in our technology don't seem like arguments for our ability to act in a long and large scale, despite being implicitly taken as such by a lot of people.
Sure, in the geological time humans study ten million years isn't much but the claim that a living creature could act in the time period is purely speculative. Speculation is fine but the rhetoric of the "Fermi Paradox" is "why don't I see of things I have only wildly speculated about, there's something weird here", which is kind of problematic.
Effectively by working to conquer cancers and age related diseases/decline, and the general effort to “extend our lives”… we are making space slightly smaller for our future selves once our propulsion technology advances to the point we can achieve decent percentages of the speed of light… which there are no real technical barriers against. From solar sails to muon fusion to all sorts of other interesting technology we have yet to develop, we may not be able to break a warp barrier and go faster than light… but if we live longer, say 10 times longer, the. Suddenly 5 years shipboard time travelling to another star system doesn’t seem so bad. 5 years in a millennium of years is equivalent to a 6 month journey for someone who will live to 100.
There are other factors that are more likely to explain why we are apparently alone: civilizations might not last long enough that they would encounter us before dying out, or that they have not yet emerged. IOW we might be alone in time more than we are alone in space.
You're posing these things as though they're axiomatic for all beings; as if these beings (which don't exist) would operate exactly as we do and not have their own cultures and ways of being distinct from our own here (of which are vastly different amongst people of other countries on Earth). It's a very narrow, human-centric view.
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But there is nothing to solve. The first conclusion should be that the assumption is simply false. We have no proof that life ubiquitous, so why hold on to it so dearly?
But even if we do, there are plenty of reasonable and plausible explanations as to why we don't see alien life. Just read the other comments. In fact, there are so many possible explanations that the challenge becomes: which one is the correct one? However, a paradox this is not.
However, since the initial Fermi discussion we have gathered some more evidence about the universe and these assumptions/estimates still seem reasonable, in some cases (e.g. the number of exoplanets) even larger than originally. So there is a contradiction, or paradox about that.
I challenge the idea that all the assumptions hidden in the claim that life is ubiquitous are seemingly reasonable. For instance, we don't have the faintest idea of how likely it is that eukaryotic life evolves from prokaryotes or if prokaryotes can themselves become complex life forms. Next, we don't know the likelihood of complex life becoming intelligent. It's not like this is some natural goal of evolution, at least as far as we know. It may have been an extremely rare accident here on earth.
There are many more such assumptions, some of which Fermi could not have known about. But we shouldn't ignore all the progress we have made since then.
Basically asking "why can't we see the interstellar empires?". Well, maybe these don't exist even if many earth-like societies exist. Maybe "colonizing" other stars is uninteresting to any society that reach level where it would be possible. Maybe there really are hard limits to such endeavors or maybe we're alone at the moment (the limited time in the universe is a factor. Life on earth took a significant fraction of the universe' lifetime to develop and the earlier universe might have been life hostile).
It's entirely unreasonable to assume that we would be able to see aliens at all nor that they'd have any interest in US.
The problem for proving will be materially improving the ability to move mass and information in sufficient quantities and at sufficient rates to have any chance of proving anything one way or the other. But in order to prove the theory you need only one instance if it exists and we can make reasoned guesses about life we understand to see if there’s life like us as an optimization. That seems like a good advantage for proving life exists.
The disproof of life in the universe is even harder - you essentially need to comb everywhere and everything for patterns that aren’t explained by the local environment to disprove. I think it’s unlikely the theory will be disproven.
The longer we go without positive proof though the more likely we can not prove it but can assume life doesn’t exist outside this planet. But we haven’t gone very far for very long in the scale of human history, and given the acceleration of advancement over the last 500 years I don’t think it’s fair to say we’ve explored the space of the problem sufficient to assume life doesn’t exist.
And if it does exist, they likely have laser sharks and antimatter bombs. That’s why the Fermi paradox is so hyped.
There can be a huge number of civilizations gravitating around a star, just as we do. But any bigger civilization, bigger than their mother star, may soon find the interstellar space more comfy and remain there, beaming directional messages (and consciousness units, a.k.a souls) between cold outposts in interstellar space.
Earth civilization is wondering why it can't see or hear anyone while almost literally living inside a beacon.
The bigger question is why you would want to exist in an entirely artificial environment far from any star, even if it makes information interchange and computation more efficient.