What do you think the Great Filter is?

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.

bradorsomething ,

The Dark Forest theory is a great answer to this paradox. Anyone more advanced has a rational choice to exterminate all competition. We haven’t found any other advanced life because it hasn’t shown up and killed us yet.

KevonLooney ,

Why would they eliminate the competition if it was way behind in technology? Do we eliminate uncontacted tribes because they might be "competition"?

If aliens exist they probably have rules against interfering with primitive species. We are more like a band of chimps than an uncontacted tribe.

bradorsomething ,

We don’t eliminate uncontacted groups any more because we’ve contacted everyone we want stuff from, and it didn’t work out well for them. Lower technology groups in the 1800’s submitted or were killed off. In a finite universe, any competition could one day try to take you out, so you take them out.

I don’t believe anyone can fathom another alien race, much less assign them ethical rules about interfering with other species. And apes are slowly being driven out of their habitat as we continue to expand.

weststadtgesicht ,

Who said that they eliminate competition that's way behind technologically? They haven't eliminated us, so apparently they don't.
But it seems plausible that they eliminate civilizations that are on the verge of becoming dangerous - still a great filter, but probably a bit further in the future.

Tudsamfa ,

We have had Millions of years of (presumably) intelligent Dinosaurs on this planet, but only 200.000 years of mankind were enough to create Civilization IV, the best Strategy game and peak of life as we know it.

So clearly, Civilization™ is what sets us apart.

Jokes aside, the thing evolution on earth spend the most time on is getting from single celled life-forms to multicellular life (~2 billion years). If what earth life found difficult is difficult for all, multicellular collaboration is way harder than photosynthesis, which evolved roughly half a billion years after life formed.

naevaTheRat ,
@naevaTheRat@lemmy.dbzer0.com avatar

Sort of fallacious to go from one case of time to happen and derive probability from it.

I'm no biologist but I don't think any of our models of super early stuff are sophisticated enough to speculate on what stages are the most or least likely.

Tudsamfa ,

You are correct, but that doesn't mean I can't speculate about it.

The ability to do photosynthesis is widely distributed throughout the bacterial domain in six different phyla, with no apparent pattern of evolution., according to this random paper I found on the internet (I'm not a biologist either).

What I can glance is that photosynthesis has (probably) evolved independently 6 time in Bacteria and 3 times in Eukaryotes.

Plants evolved to photosynthesise after photosynthesising bacteria already existed for billions of years.

(But then we have to also acknowledge that multicellular life evolved like 25 times in Eukaryotes, and the Eukaryote - aka Mitochondria-"Powerhouse of the cell"-haver- is the real big step as it only happened once to our knowledge).

squirrelwithnut ,

We're currently in it. Failing to create a clean, renewable, and scalable energy source powerful enough to run a society that is ever increasing in both population and technology without destroying their only inhabited planet has got to be the most common great filter.

Asteroids strikes, super volcanoes, solar CMEs, and other planetary or cosmetic phenomena that exactly line up in both severity and timing are too rare IMO.

Every society that attempts to progress from Type 1 to Type 2 has to deal with energy production. Most will fail and they will either regress/stagnate or destroy themselves. Very few will successfully solve the energy problem before it is too late.

Tudsamfa ,

A filter for sure, but not a great one. Call me optimistic, but I don't think that will set us back more than 10.000 years. If humanity can survive, society will re-emerge, and we are back here 2-3000 years into the future.

Is +5°C Earth a good place to be? No. Will the majority of humans die? Absolutely. Will the descendants get to try this society thing again? I believe so.

On a cosmic scale 10.000 years is just a setback, and cannot be considered a great filter.

Kyrgizion ,

Unfortunately we've pretty much used up all easily available resources. Anyone 'starting over' would have a much harder time getting the things they need to really get the ball rolling again.

When humans first discovered gold they practically only had to scoop it out of rivers. You'll be hard pressed to find any streams with such appreciable production anywhere in the world today.

Cryophilia OP ,

We've already discovered fission and photocells. We're past the point of needing fossil fuels for a new civilization (or existing civilization). Fossil fuels are only hanging around for economic reasons.

Spacehooks ,

Assuming that knowledge and resource locations are retained. Roman's had great concrete. Took a long time to reestablish what Humans already had and mixing raw materials is not complicated.

After the Roman Empire, the use of burned lime and pozzolana was greatly reduced. Low kiln temperatures in the burning of lime, lack of pozzolana, and poor mixing all contributed to a decline in the quality of concrete and mortar

We need a Foundation project to restart society If we want to avoid this. Worst case solar cells becomes myth like Greek fire.

Tudsamfa ,

I think that is thinking a bit too narrow. A lot of the stuff we use today might just be our bronze to our successors iron - you can build an unstable society on either. And what we do use up today could still work if used more efficiently - we might not have enough rare metals to give everyone a smartphone in the post-post-apocalypse, but I could see us still launching satellites if only big governments had computers - because they did.

AA5B ,

Exponential functions. Seriously. You meet crisis after crisis, each having a risk of ending civilization, but that risk never goes away. It keeps multiplying and multiplying, until you realize the risk curve is approaching a vertical line

Cryophilia OP ,

Why would risk go up over time? For humanity, we're pretty much at the point that very little could end our species now.

Brickhead92 ,

Well except, obviously, for humanity. That's our greatest enemy, and it seems to be shown more frequently.

Cryophilia OP ,

We would be hard pressed to end our own species either. Even global thermonuclear war would end civilization but not our species.

DeanFogg , (edited )

Edit: This mf just jinxed humanity

Depends on the amount of nukes.

Acidifying oceans also dares a cascading effect that would wipe us out.

Disease.

Also, think about globale warming. The core of the sun is 27 million degrees. 130 degrees is enough to make the surface unbearable, higher than that is going to be>!!< uninhabitable.

Also let's not forget space is wild, meteors or GRBs can take us out instantly

Spacehooks ,

Universe 25 experiment.
My take away from it is when society gets bored and loses goals it's over. If the mice had some predators they probably wouldn't have collapsed.
Humans don't have predators but have dreams that we worked toward amd stimulate us. Once we lose that it's like what happened Walle. Stuck in a system slowly dying full of apathy.

magikmw ,

I think it's incompetence.

Cryophilia OP ,

Fermi, to aliens: "git gud"

Contramuffin ,

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

LodeMike ,

It's very very obviously the speed of light.

Melvin_Ferd , (edited )

Resources often get squandered on trivial vanity and novelty products instead of being channeled into advancing science and medicine. Imagine if we had a cosmic ledger tracking every resource used to develop simple items, like a pencil. It would show countless fires burned and animals consumed just to fuel the human ingenuity required for lumber, materials, and mining. Now, think about how many more resources are required for rockets, heat shields, and life support systems. Extend that to space stations, energy capture, and escaping Earth’s gravity.The resources on a planet are abundant, and nothing is ever truly destroyed. However, we’ve often allocated too much to building flat-screen TVs, leaving little for constructing even a modest space station in orbit, let alone an interstellar spaceship. It's as if the planet offers a finite amount of resources, challenging its inhabitants to focus on space travel. Only a species wise enough to stay on track can unlock the universe's resources. Otherwise, we risk ending up like Australian pines, choking ourselves out in our isolated star systems, having wasted our potential.

Imagine it like interstellar travelling having a single path to achieve it while the path to self destruction is limitless.

theywilleatthestars ,

Either multicellular life or that societies that are bent on expansion at any cost tend to destroy their planet's ecosystem before they can establish themselves outside of it.
Not making a definitive claim on either, obvs. We have an extremely low sample size after all.

Nutteman ,
@Nutteman@lemmy.world avatar

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?

Melvin_Ferd ,

I mean then how did they become a life form

Nutteman ,
@Nutteman@lemmy.world avatar

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.

weeeeum ,

I think it would be nuclear warfare. Nuclear fission is a universal development for any advanced civilization. It would be easy to construct a nuclear bomb in an advanced civilization. Once a few rogue/pariah states start making them, everyone's screwed.

Making nukes is easy, the only reason we don't see more nuclear states on earth is because of the international backlash. With a couple more Iran and North Korea's we'll likely meet the filter ourselves.

RealFknNito ,
@RealFknNito@lemmy.world avatar

Hard to determine with what we know. We haven't met any other intelligent species which suggests we've passed the filter. Yet, making that conclusion before knowing there are no others to meet is too presumptuous. But, if I were to guess, I'd think the filter is adaptability.

We're superior to animals for being able to use tools, live in radically different climates, and shape every spot on earth into a livable climate. Even on Mars, the moon, and space. How else would a species venture through space if they can't adapt?

That might be too general a concept for the question though.

doctordevice ,

We haven't progressed far enough to be detectable by intelligent life in other star systems, even the closest ones. The filter can easily be in front of us. It could just simply be that interstellar space travel is too infeasible, so intelligent species never reach beyond their home system.

RealFknNito ,
@RealFknNito@lemmy.world avatar

Yet we haven't even found other planets with complex dumb life, much less ones with intelligence, communicative life. Nothing like what we have on Earth, not even close. Either space is too big or we're past the filter.

doctordevice ,

We are nowhere near advanced enough to say that life, complex or intelligent, doesn't exist anywhere near us. There is no reason to believe an intelligent spacefaring race would make themselves so obviously detectable that us stupid primates could see them. And for non-intelligent life, we've been able to confirm mere thousands of planets. We have a very long way to go before we can start talking about the meaningfulness of a lack of life signatures in the atmosphere.

cynar ,

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.

Cryophilia OP ,

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.

cynar ,

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.

Cryophilia OP ,

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"

Asafum ,

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. :(

cynar ,

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.

SwingingTheLamp ,

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.

Cryophilia OP ,

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.

Gradually_Adjusting ,
@Gradually_Adjusting@lemmy.world avatar

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.

Hugin ,

An alternative is we are among the first. Third generation stars are the ones that have planets with enough heavy elements to allow for complex chemistry. Sol (our star) is thought to be among the first batch of third generation stars in our gallexy.

Light speed does seem to be the upper speed limit for the universe. Talking that into account we probably haven't had a chance to see other early life as it would likely be spread pretty thin right now.

Cryophilia OP ,

Yeah, I have a gut feeling that a lot of the variables in the Fermi equation are a little too generous.

Kyrgizion ,

I do agree that in the grand scale of things we're actually very early. That alone would explain a lot.

sxan ,
@sxan@midwest.social avatar

This is my favorite, mainly because it's been well argued by some respectable scientists.

Another is that we're in a simulation, and aliens aren't part of it. There are also some very good statistics pointing to the simulation theory, from just sheer scale.

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