The Great Filter is the idea that, in the development of life from the earliest stages of abiogenesis to reaching the highest levels of development on the Kardashev scale, there is a barrier to development that makes detectable extraterrestrial life exceedingly rare. The Great Filter is one possible resolution of the Fermi paradox.
https://en.wikipedia.org/wiki/Great_Filter
The Fermi paradox is the discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high likelihood of its existence. As a 2015 article put it, “If life is so easy, someone from somewhere must have come calling by now.”
https://en.wikipedia.org/wiki/Fermi_paradox
Personally I think it’s photosynthesis. Life itself developed and spread but photosynthesis started an inevitable chain of ever-greater and more-efficient life. I think a random chain of mutations that turns carbon-based proto-life into something that can harvest light energy is wildly unlikely, even after the wildly unlikely event of life beginning in the first place.
I have no data to back that up, just a guess.
I think it’s incompetence.
Fermi, to aliens: “git gud”
I personally find the kardashev scale a pretty terrible way to measure the success of a civilization. Maybe the most successful life forms don’t become technologically obsessed materialists determined to colonize everything habitable and drain the resources of everything else, yknow?
I mean then how did they become a life form
I wasn’t clear enough I don’t think when I wrote that. I meant that as in the most successful intelligent life forms don’t separate themselves from their ecosystems nor disrupt it in the way we do.
It’s very very obviously the speed of light.
My thought is the evolution of intelligent life itself. If you think about it, intelligence is contrary to most of the principles of evolution. You spend a shit ton of energy to think, and you don’t really get much back for that investment until you start building a civilization.
As far as we can tell, sufficient intelligence to build technological civilizations has only evolved once in the entire history of the Earth, and even then humans almost went extinct
Pushing Ice by Alastair Reynolds is one of my favorite scifi books and it deals with this question in an interesting way. It proposes that Time is the great filter. Life exists in this galaxy, but intelligent life is so fleeting when considering galactic distances that the probability of one sentient lifeform finding another during their “peaks” is vanishingly small. Extinction, societal collapse, evolution to a higher form, whatever you want to imagine, it all gets in the way of the fantasy of meeting a thinking being from another planet.
deleted by creator
We actually spend a great deal of effort preventing it. Environmentalism is a really big thing these days.
But even if we didn’t, it’s not an extinction event for us. Humans are actually doing extremely well.
It’s a society (or the whole humanity) becoming big enough to survive even when ignorant murderers are the elite and the majority of it, and civilized people - a smaller part and almost a property, similar to animals in a zoo.
When such a point is reached, the former will make the transition, and the latter will diminish over time. Then it just has no future.
A bit like with Ottoman empire and Qajar Iran, only on the scale of the whole humanity there won’t be someone else to buy weapons and technologies from to keep going. Then some of the previously passable filters will kick in. Like hunger or resource scarcity.
Howabout a reasonably advanced civilization destroying itself and its homeworld after exploiting and then running out of petroleum?
I think it’s a fair thought that any form of life doesn’t perfectly recycle their resources and all forms of life give off waste for other life to utilize. That said, a reasonably advanced civilization might just inevitably grow to the size where the waste they put off makes their planet unlivable for them before they can take action to control it.
For us, it’s carbon dioxide.
Don’t forget plastics and pesticides! Those get everywhere, and many are bioavailable by design.
Oil has a bad reputation but how lucky we are to have it. How does a civilization on a planet without hydrocarbons make the leap to a technological species?
It’s not impossible, but it’s got to be a lot harder.
Kelp farms? Domesticated bamboo? We need large areas of land to grow food anyway, we just skipped the charcoal agriculture step. Lathes and the three plate method are the real heroes of industry any way.
A slower ascension into the computing age could mean a more stable set of cultures and a more uniform global situation to avoid anthropogenic filters. Bright candles and all that.
I think there are many great filters, but I think one of those filters is fighting over limited resources and wars. Perhaps limited to humans/earth, but I doubt it. Nukes, dropping rocks from orbit, and theoretical (but possible) weapons like black hole bombs are all going to tempt irrational beings to take someone’s stuff.
We have to be extremely careful that we don’t accidentally trigger a weapon that is going to kill or dramatically cripple our civilization before we become a truly interstellar species. There is so much to learn out there, while so many people are currently focused on the wrong things such as minor conflicts or what children aren’t allowed to learn.
We have to be extremely careful that we don’t accidentally trigger a weapon that is going to kill or dramatically cripple our civilization before we become a truly interstellar species.
Great filter confirmed to be oopsie-daisies
That’s what everyone was thinking with the LHC. Really should put oopsie labs off world.
Your answer doesn’t make sense.
“Photosynthesis” is a positive development for life. The great filter must be a negative development: it’s a filter or a barrier that keeps life from achieving long term extra terrestrial survival.
So “climate change” would be an answer. Or “fuel depletion” (to which photosynthesis may be a solution). But the filter is the mechanism by which life forms are prevented from progressing.
I was suggesting that photosynthesis is a very unlikely mutation to occur and thus its unlikeliness means most life, if it emerges, won’t progress to that stage.
The filter doesn’t have to be ahead of us, it could be some stage of development that we’ve already passed. Like photosynthesis, or the development of consciousness. If, out of all life that develops, only a tiny fraction ever develops photosynthesis, the universe would be largely devoid of any life that we can presently detect. Despite us being the lucky lifeform that did develop photosynthesis in our past.
Regardless: photosynthesis is a possible solution to avoid the filter. Not the filter itself.
You can’t filter something in
The failure to develop photosynthesis is the filter. I don’t know how you’re not getting this. No photosynthesis, no complex life, no sentience, no interstellar civilization.
You started here
Personally I think it’s photosynthesis.
Now you’re here
The failure to develop photosynthesis
I think you got it! Good job!
I’m sorry to tell you this, but I think you might be stupid.
Space itself. I believe there are other intelligent life forms out there and some of those happen to be close enough to communicate to each other/discover each other. We just hit the unlucky(or lucky) spot that we are simply too far away.
Man that would suck
Kind of like we don’t have hive minds so they just think we are regular animals.
I would say it’s the size of the universe and the fact that it is still expanding at an accelerated rate.
If the speed of light is really the “top speed” of the universe, it is inadequate for interstellar travel. It is barely good enough for timely communication, and not really even that.
Life can be as likely as it wants to be, but it seems to me that we’re all quite divided, to the point of not being able to communicate at all with other potential intelligent species.
Isn’t the fermi paradox specifically dealing with detection tho? Not just travel or communication.
This universe being unfriendly to interstellar and especially intergalactic travel would seriously hamper a galactic civilization, and thus be less likely for us to notice them.
There might be hundreds of civilizations out there, each having only expanded to a few dozen stars, not caring to go further. Even the makeup of the interstellar medium might be incredibly dangerous, basically necessitating generation ships to cross. Large scale expansion might simply be too hard.
I suppose I was focusing on detecting some sort of communications. It still matters that when we see objects at great distance in space, it’s the objects in the distant past
That expansion at an accelerated rate - that’s just so eerie when you think about it. The furthest objects we can see right now will slip away out of reach forever for the next generation, and so on. It’s crazy to think that as time goes on, there will be less and less universe to observe.
One of the weirdest facts. One that really makes you feel so small.
That’s something really interesting, though. When we look at distant objects, we aren’t limited by the distance they’re at right now. We’re limited by the distance they were at when they emitted the light.
So the observable universe is still growing because the edge of that bubble is such a long time ago that everything was still much closer together.
But the light that reaches us is constantly getting stretched (red-shifted), so I’m not sure that our bubble is growing. Instead when they’re stretched too thin, we won’t be able to see it. I’m not 100% sure on the expansion rate of the universe and the pace of red shifting. Also, eventually all the galaxies are expected to be pushed so far away from each other due to the pressures exerted by Dark Energy, that soon we’ll only be able to see just the stars of our Milky Way.
I don’t think there is a single filter. My personal gut feeling however is that the jump to “specialised generalists” would be a major hurdle.
Early human civilizations are very prone to collapsing. A few bad years of rain, or an unexpected change of temperature would effectively destroy them. Making the jump from nomadic tribal to a civilisation capable of supporting the specialists needed for technology is apparently extremely fragile.
Earth also has an interesting curiosity. Our moon is extremely large, compared to earth. It also acts as a gyroscopic stabiliser. This keeps the earth from wobbling on its axis. Such a wobble would be devastating for a civilisation making the jump to technological. Even on earth, we are in a period of abnormal stability.
I suspect a good number of civilizations bottleneck at this jump. They might be capable of making the shift, but get knocked back down each time it starts to happen.
Earth also has an interesting curiosity. Our moon is extremely large, compared to earth. It also acts as a gyroscopic stabiliser. This keeps the earth from wobbling on its axis. Such a wobble would be devastating for a civilisation making the jump to technological. Even on earth, we are in a period of abnormal stability.
There seem to be so many coincidences that make our solar system unique that it’s really upsetting lol It’s like we are so perfect for stability because of things like Jupiter keeping the inner system “clean” of large impactors, our part of the galaxy being more “quiet” than typical as far as supernovae, stuff like that which makes it seem even less likely for life to exist anywhere else. :(
Life will almost certainly be fairly common, given the right conditions. On earth, it seems to have appeared not long after conditions made it possible. We either won the lottery on the first week, or the odds aren’t actually that bad.
The problem is, we can’t detect life right now. We can only see potential communicating civilisations. These are a lot rarer. We currently know of 1, humanity. That will change in the next few years. We have telescopes being designed/built capable of detecting the gasses in the atmosphere of an earth sized planet. While we won’t recognise all life types this way, a lot will show up in abnormal gasses, e.g. free oxygen. This should help bound the possibilities a lot.
Speaking of our moon, the fact that it’s roughly the same size as the sun as seen from earth and the fact that this is a complete coincidence blows my mind. Like there’s no reason for that to be the case. Total eclipses like ours (where you can see the corona) are very rare.
Even more so, the moon is slowly moving away from the earth. A couple of million years ago, it would have completely covered the sun. In a couple of million years, it will not fully cover the disc.
A million years is a long time for humanity, but a blink on the timescale of moons and stars. We didn’t just luck out with the moon’s large size, but also with the timing of our evolution.
That’s nuts. In two million years, humans will be sighing and saying wistfully “if I had a time machine, I’d want to go back to the time of the full eclipses, like 2024”
Honesty, I don’t think that there is a Great Filter. The Fermi Paradox strikes me as not very well-reasoned. A whole hell of a lot of things would have to go exactly right for civilizations to make contact, rather than it being the default assumption. There are lots of filters, not just one Great one.
But the closest to a Great Filter is that space is really, really. stupendously big. The chances of even detecting each other across such distances is vanishingly small, much less traversing them. Add in the difficulty of jumping the metabolic energy gap to become complex life, and that could reduce the density of civilizations down to a level that they’re just not close enough to each other in spacetime to admit even the possibility of contact. And we’re hanging our hat on some highly-speculative concepts like alien mega-structures harnessing whole solar systems to allow detection.
I think a lot of persnickety, smaller filters combine to make interstellar contact between civilizations against long odds. Perhaps the best we’ll get is spectral signatures from distant planets that are almost-conclusive proof of some sort of life.
I think at some point, almost certainly not in our lifetimes, we’ll detect the spectroscopic signatures of a planet that has an atmospheric makeup that HAS to be from life, but with no detectable signs of any civilization. Just nonsentient life. And we may never be able to get there.
I think you’re probably closest. There aren’t “filters” so much as we live in a universe that can only support life on a highly contingent basis, entirely by accident, at random intervals. It’s filters all the way down, really. None of us are getting out alive, might as well enjoy it while it lasts.
There’s a lot of possibilities.
My top contender would be a desire to explore, which probably requires consciousness. Given that we have pretty much no idea what leads to consciousness, it can be guessed (dubiously) that if it arose more easily then we’d have an explanation by now. It could be that it’s an extremely rare phenomenon, and there may even be other planets with “intelligent” but mechanistic beings that act entirely for their own survival and don’t build civilizations or explore much.
Second would be intergalactic and to a lesser degree interstellar travel. If we assume both 1) intelligent civilizations are extremely rare and 2) faster-than-light transportation is impossible, it could be that everyone is just too spread out to make contact.
Third, and the one I most feel is right but it requires pretending I understand quantum physics (which I don’t) and probably offending many that do, is the notion that the concrete universe is not large but small and has no objective existence independent of our respective perceptions, and any part of the universe that’s invisible is a mere wave function that will only have concrete reality upon our perceiving it. I make the further dubious assumption that conscious beings can’t be part of the wave function. So there.
conscious beings can’t be part of the wave function
That’s not how any of this works. Your brain is made out of regular matter, not special fancy matter.
I don’t know if the type of matter matters, rather I’m basing in on the idea that measurement collapses the wave function, and consciousness does measure things
Your brain isn’t what “collapses the wave function”, it’s the measuring device that you use. You can do a double slit experiment and watch it with your eyes the whole time. Light will still act as a wave until you interact with it experimentally.
You are reading too much Deepak Chopra. Your brain is just a computer made out of meat. It’s not magic.
Second would be intergalactic and to a lesser degree interstellar travel. If we assume both 1) intelligent civilizations are extremely rare and 2) faster-than-light transportation is impossible, it could be that everyone is just too spread out to make contact.
Not just too spread out to make contact, too spread out to even detect each other’s presence
For your final point, that’s not what that means. It’s not “observation” that collapses the wave function, at least as you’re understanding the word. It’s any interaction that requires the information to be known. That includes any particle interactions. It’s not consciousness that matters. When we “make a measurement” it’s only recording information of an interaction. It doesn’t actually matter that we record it, only that there was an interaction. There is zero metaphysical consciousness mumbo-jumbo involved.
That’s what I thought too, but according to Sabine Hossenfelder there actually is, we just choose not to speak about it. I don’t really know enough about quantum physics to make my own judgement.
That video makes no argument for consciousness being required. Also, Sabine is not a reliable source of information. She is confident and convincing, but that doesn’t make her accurate or correct.
For an example, not related to this topic: https://youtu.be/s7XAxiJGJdg?si=S0IkGdF_EV5If_wJ
