> the hypothesis postulates that previously a species different from ours had achieved high intelligence and technological civilization on this planet
An interesting special version of this hypothesis is that if a species has achieved truly high intelligence and advanced technology, it may by design not have left any traces. Not because of modesty but because long-term sustainable existence actually required being light on environmental impact.
Changing your environment at planetary scale and breakneck speed is not necessarily the pinnacle of intelligence, certainly not if you have manifestly not yet understood all its intricacies, interdependence etc. A lack of understanding coupled with aggressive random interventions may even affect the very survival of a species.
The downside of the deep-sea tree-huger cephalopod scenario is that it is even harder to falsify...
> Changing your environment at planetary scale and breakneck speed is not necessarily the pinnacle of intelligence, certainly not if you have manifestly not yet understood all its intricacies, interdependence etc. A lack of understanding coupled with aggressive random interventions may even affect the very survival of a species.
Well apparently their strategy to ensure survival didn't do too well since we're discussing an extinct civilization here.
> Well apparently their strategy to ensure survival didn't do too well since we're discussing an extinct civilization here.
Maybe they're "extinct here", because they just left.
BTW. this is actually a big theme in David Brin's Uplift saga[0]. Basically, you have all these alien civilizations, more and less friendly to each other, but bound by some common rules, some of which regulate sustainable colonization. This includes an exclusive right to settle and use a habitable planet with a biosphere for $whatever number of millenia, and after that time, the civilization there is supposed to pack up and leave, fix environmental damage, and erase any trace of their existence, commonly achieved by dumping everything into the planet's subduction zones so it gets naturally recycled; after that, the planet is to lie fallow for ${some other number} of millenia, to give nature a chance at creating more biodiversity and stuff.
>Well apparently their strategy to ensure survival didn't do too well since we're discussing an extinct civilization here.
Not necessarily. They could have existed hundreds of millions of years ago, and become victims of the Chixhulub asteroid impact or other huge natural disaster after successfully maintaining an advanced civilization for hundreds of thousands of years, FAR longer than our probably ill-fated civilization has managed. They might have also left the planet. Or they could have transcended into energy beings.
External factors are the obvious answer, the Earth and its planetary environment are actively evolving over geological scales.
Another intriguing possibility is some sort of senility setting in after long-term evolutionary success. The intelligent cephalopods eventually got tired seeking answers from a mysterious Universe and settled for the quite life.
"their strategy to ensure survival didn't do too well "
We aren't doing that well either. Too early to tell. But I think we've shown enough problems to at least speculate on how we will do during the coming 'great filters'.
A theory about a previous advanced civilization must first and foremost explain how and why it skipped using all the obvious under-your-feet materials and fuel sources in its initial phase.
Well, the carbon our civilization has been burning started forming about 350-300 million years ago (from Carboniferous period, it's in the name), and the Silurian period was 420-440 million years ago, so what Silurians would have had under their tentacles isn't what we bootstrapped our society with.
Maybe they used plenty of the under-your-tentacles fuel sources, but it's been a very long time since, and it's hard to tell.
One answer is that this "initial phase" may have lasted a total of a few hundred years, which is a tiny blip on geological scales. Even with humans, it looks like it's going that way.
And taking it even further, maybe they still exist, but have advanced so far they are undetectable to our simple minds and senses, similar to how an ant or bacteria has no idea about our existence. Maybe there are millions of advanced species that we can't detect, considering that there are millions of species we are aware of, and statistically it's unlikely that we would be the most advanced.
That's actually a factor that diseases aim for. Mortal diseases don't spread as much as the ones that don't damage the host as much. Because of this, severe diseases sometimes evolve into mild ones.
Surprised the article didn't mention the Paleocene–Eocene Thermal Maximum (PETM) [0] and it's interesting relation to "a species different from ours had achieved high intelligence and technological civilization on this planet."
For those unaware, the PETM was a rapid increasing in global temperature (and CO2 concentrations) around between 60-50 million years ago. This lead to a minor (on a geological time scale, major for those creatures living through it) climate crisis.
The cause for the rapid increase in temperatures at this time is still the subject of deep debate and largely unknown. However how very "out there" hypothesis, not even mentioned on the wikipedia page, is that this could have been when a civilization such as our experience an event more-or-less identical to our own current climate crisis caused by the rapid use of hydro-carbons.
Of course, the biggest challenge with this hypothesis is, as pointed out in the article, a civilization like this would not leave a trace on the geological record. So there's really no reasonable way to have much evidence in favor of this possible explanation.
But since here about this I've been fascinated by the problem of sending messages to the future. Suppose we come to realize that rapid use of hydrocarbons does most certainly lead to the destruction of any civilization foolish enough to tread this path. The most reasonable focus of scientific effort that would be to figure a way to warn the next advanced civilization on this planet in hopes they might not meet the same fate. But presuming that civilization is 50 million years in the future, how could this be done?
Some ideas for sending messages to the next civilization.
1. Genetically modify as many wild plants and animals as we can to have a message encoded in their DNA, and release them back into the wild.
2. In areas that we expect to be geologically not much changed over the next 50 million years arrange concentrations of long lived radioactive materials in patterns that are obviously not natural. Encode a message in those patterns.
3. We could probably do something on the moon with nuclear weapons that could make a long fairly straight trench or series of parallel trenches that would be visible in telescopes and either be obviously non-natural or at least interesting enough to get them to go take a look.
Leave millions of metal spheres, cubes, tetrahedrons, octahedrons, dodecahedrons, and icosahedrons there which contain messages inside.
Google is telling me that any given spot on the moon gets hit be a meteoroid of ping pong ball size or greater about every 1000 years, so many of the messages will likely be destroyed over 50 million years, but maybe enough will make it.
BTW, is meteoroid the correct term? That's what Google's summary used and according to the dictionary definition as a small body that would become a meteor if it entered the Earth's atmosphere it would be correct but when we are talking about impacts on other planets or moons I'm not sure we should restrict meteor and meteorite to just meteoroids that are in or have hit after passing through Earth's atmosphere, respectively.
> a rapid increasing in global temperature (and CO2 concentrations) around between 60-50 million years ago
> a civilization like this would not leave a trace on the geological record
Am curious: if dinosaurs can be found with intact skin [1], after 110 million years, why not remains of the civilization's "people" (bones etc.) after 60-50 million years?
Not a biologist, but OTOH they might have had a very different body structure that doesn't conserve well, e.g. like molluscs.
Or maybe we _did__ find their remains and just have no idea they were part of an intelligent civilization. I mean, that's not a question any respectable researcher would be inclined to raise in the paper about the discovery...
If PETM was due to large scale use of hydrocarbons, there should be evidence of depletion in the strata, right? For example, currently not all sources are uniformly exploited -- some coal seams and oilfields are all but depleted, others are currently being extracted, and others are yet to be found/exploited.
We should have seen signs of similar non-uniform usage in the strata from before that time period. I wonder if any research has been done on this.
> If PETM was due to large scale use of hydrocarbons, there should be evidence of depletion in the strata, right?
And all the byproducts of this use. We are leaving abundant traces of our existence basically everywhere. We can see it in the ground, in the seas, in the ice caps. Our existence will be very obvious to anything caring to just dig for quite a long time.
I'm not sure if that's a safe assumption. Do we know what the sources we are exploiting right now are going to look like in tens of millions of years? Our models of the evolution of hydrocarbon reserves are based on those we've found, and we simply assume the differences between different deposits are natural in origin. It's easily possible that places where we didn't find hydrocarbons did in fact have them at a previous point in time, or that there was more in a given reserve in the past.
Has someone done the math on what Hydrocarbons (coil, oil) would have been available 60 million years ago?
Would they have been using the same deposits we are suing, or would new deposits have formed over the last 60 million years?
Or could they have depleted their own, but what was un-usable 60 million years ago, have become usable today. Like something that was marsh land 60 million years ago, be coal today?
> current climate crisis caused by the rapid use of hydro-carbons.
The problem I see is they either had to use sustainable hydrocarbons (so, carbon-neutral) or they would have used up the fossil fuels we're currently using.
Nothing built with "usual" materials we have, mostly because of the constant movements and subduction of tectonic plates, as well as volcanism and erosion.
Think about something you believe would last 50 million years. I am sure someone will be able to point out how and why that would just disappear after such ridiculous amount of time.
Wrong timescale though. 10000 years vs. 50 million. Millions of years is a very very very long time, our intuition is often wrong about timescales like that. For example a lot of modern land was still molten rock underground and vice versa.
> Reaching “only” the Neolithic stage could be described as a “Silurian hypothesis light”; it’s not highly significant achievement for a species, and even such a species can significantly turn over the planet’s fauna. Even our hunter-gathering (Paleolithic) ancestors hunted a number of large animal species to extinction (you don’t have to kill every last mammoth or giant bird to do that), and our farming ancestors (before the advent of even the simple most metal tools) caused massive modifications of the fauna and florae of extensive landscapes. Some of these faunal changes might be detectable millions of years into the future.
To be fair, a species can achieve that without any intelligence or civilization whatsoever if they just manage to grow their population enough.
I think the most extreme species in that regard would be cyanobacteria, which changed the composition of Earth's atmosphere from methane and CO2 to oxygen [1] - and subsequently caused the metabolism of almost all other species to become oxygen-based.
This change is not just "detectable" today, it became the basis of most life on the planet.
Another one is the Azolla event hypothesis where a variety of fern grew so much that as it died and sank to the ocean it sequestered massive amounts of carbon, enough to alter the climate.
Before bony fish ascended to their current dominance, there were plenty of other fast predators in the sea. If lack of predators is a requirement for cephalopod civilization, the window probably closes much earlier than the Cretaceous.
An alternative, possibly more optimistic (?) hypothesis: the first step of their civilization would be collective defense from large predators. Population concentrations would then make farming very advantageous. Yes, I'm more a scifi writer than biologist.
It could be as simple as the evolution of fish jaws making the mollusc shell insufficient defense. Or fish eyes/pressure sense/etc developing enough to notice hiding molluscs better. It's plausible that earlier predators were below the threshold of extinction-level risk. Flipping the perspective, humans were below an extinction-level risk for most large land animals for a long time.
The author didn’t seem to address how cephalopods would be able to develop civilization without demonstrating a similar aptitude for highly coordinated complex social behavior or the transference of ideas (complex language). These both seem necessary for development of a complex civilization as ideas can improve and spread much faster than biological information. It’s somewhat ironic, considering the opening salvo was related to an improbable language hypothesis.
Despite being mollusks, like clams and oysters, these animals have very large brains and exhibit a curious, enigmatic intelligence.
I followed them through the sea, and also began reading about them, and one of the first things I learned came as a shock: They have extremely short lives — just one or two years.
Humans do seem to have some the longest life spans on the planet, and that's an important adaptation -- "grandmother hypothesis" and all that. I can see that generational knowledge is big deal, even in my own family, and in my coworkers' families.
Or you can look at the family of (ironically) Charles Darwin, with Francis Galton, and so forth
The outliers among primates move the civilization forward. So just having a few people with big brains, who absorb knowledge from their predecessors, is a big deal.
Though of course there could be some cephalopod species that evolved to live 100 years ... and then for some reason they disappeared, or lost that adaptation
Not only short lifespan (some live four years), but all species die after laying eggs or after the eggs hatch so there can only be genetic transfer of information like the social insects, ants and termites. There would need to be some evolutionary leap to have them survive longer than required now or extraordinary genetic engineering ala Children of Time.
One point to note is that humans evolved from apes at a quick pace. I've heard claims that longer life-span, the ability to engage in complex vocalizations, opposable thumbs, upright stance, binocular vision and so-forth are all pretty recent innovation over evolutionary short period, with large brain size turning out to be last addition.
The human package might be not much more complex than "start with a rock-throwing mob and features providing benefits"
So, on the surface, you could have a species that sprinted to all the features required for civilization - and then destroyed itself in a blaze of less-than-glory as we seem on a trajectory to do.
Edit: Note, I should add that I'd actually doubt this scenario could happen only because the evolution of human seems part of the general acceleration of evolution that can be seen throughout geological history.
>One point to note is that humans evolved from apes at a quick pace. I've heard claims that longer life-span, the ability to engage in complex vocalizations, opposable thumbs, upright stance, binocular vision and so-forth are all pretty recent innovation over evolutionary short period, with large brain size turning out to be last addition.
It is interesting how we evolved all these necessary things pretty quickly, though if we look at other apes, they generally also possess opposable thumbs and binocular vision. Sometimes I wonder if there was help, such as a large, black monolith...
There is discussion in the article about cephalopod communication, and how they use complex patterning and physical movement to communicate with each other. Is their level of communication and their information transfer speed as high as language? I don't think we can know very well without asking a cephalopod.
Now, that whole section is talking about modern cuttlefish, so I would agree with you regarding the author's hypothetical nautilus civilization.
> s their level of communication and their information transfer speed as high as language?
First, spoken language isn't extraordinarily fast. Most of us here have experienced points in our lives where speech has seemed laboriously slow. Second, we have through much of recorded history, relied upon correspondence and the written word, where communicating a few sentences worth of ideas took weeks.
It is not outlandish to think that complicated, colorful shapes on the cuttlefish's back (pictures in the link, if you need a reminder) could convey an entire sentence' worth of information. With a refresh rate of what, 5 seconds? More than enough for human-speech-level speed.
Whatever other challenges they face, communication just isn't one of those.
I guess the part that I could’ve been more explicit about is that I am thinking both complex language and complex language skills being necessary together to push civilization forward. The takeaway I had from the articles communication discussion was that their communication, while unique, is focused directly on mating, and predation (or avoiding predation). Those goals seem to be the norm in the animal kingdom. While I think the argument could be made that the human demonstrations can be to the same ends, they are many more layers of abstraction in between which is what ends up creating complex civilization.
(Eg, status is a form of mating, but we humans have so many tangential levels of displaying status that technology like a Lamborghini can become a mating signal, rather than using pure dominance. The combination of complex social behaviors and communication are necessary before the technology develops)
Memorized inherited tacit knowledge around campfires may had been our own specie's cultural medium, but other ways (with slower bitrate) can easily be entertained.
Vocalizations and their evolution were banned from discussion in the Royal Society because they did not leave a fossil record, so even meta-science was harder back then.
The cephalopods we observe today would be many millions of years removed from the Silurian cephalopods. It would be like trying to gauge the language capabilities of humans from observing squirrels.
As for knowledge transfer, we know that they can teach other how to perform certain tasks. But beyond that, there seems to be a lack of research. Do they have complex language and can they transfer abstract “ideas”? My guess would be yes, but they communicate through color changes in ways that we have a hard time understanding. It seems likely that birds and whales have complex language, but we haven’t cracked the code on that even though their communication is much more like ours. Hopefully we find out some day.
My guess is that abstract ideas is an outgrowth of language and also necessary for the development of the complex societies the article is positing. I would also be careful not to conflate complex language (for example, dialects in whales) with the development of complex abstract ideas (for example, mathematics). It seems to me the latter is necessary for the complexity discussed, but unclear if the extent to which it exists in other species. But I agree, hopefully we can learn more someday on the way they are both similar and dissimilar to human cognition.
(I should add that there are some like Stephen Meyer who think certain abstract cognition is more magical and unable to come from basic evolution, but this has a theistic bent)
I often think that a more interesting question would be that if there were another civilisation here on earth right now, would we even recognise it as such?
We are terribly preoccupied with tool use and physical artefacts as a defining factor of intelligence - anthropocentrism is of course pretty much inevitable, even when we talk of cephalopods.
> We are terribly preoccupied with tool use and physical artefacts as a defining factor of intelligence
In the context of civilisation, intelligence isn’t enough. Nomadic tribes are sapient, intelligent and have rich cultures, but they aren’t strictly civilisations.
The urban distinction is important because of economies of scale: pastoral societies are energy constrained. That doesn’t make them less interesting, again strictly speaking, personally it sort of does, but it does make them less powerful.
Within the Silurian context, the urban distinction is almost demanding: if humans stopped at Neolithic pastoralism, there is a good chance all evidence of our tool use would have disappeared within a few millennia, let alone millions of years.
Maybe but it's also because these things are evidence of cultural transmission - a thing for which there hasn't been strong evidence of in other species and people do look for it in other ways.
When talking about aliens people often use the word "civilisation" to mean just "intelligence" and perhaps that's what you're doing because you're thinking about something that doesn't resemble a human civilisation. I agree with you that an alien intelligence might be very different from a human civilisation. Also, an alien intelligence might not even qualify as a form of life (it might be an artificial intelligence).
our senses are only equipped to experience small subsets of the whole - there's a huge range of sounds impercetible to human ears, our eyes can only perceive light in the visible spectrum, a dog's nose can detect orders of magnitude more information than a human's.
if the five senses can only percieve a fraction of that which they have been honed for over millennia, it's not unreasonable to wonder if there is much more to the world/earth than meets the eye, inaccessible and unintelligible to physical ape life or existing in ways we aren't equipped to percieve.
Readit News
An interesting special version of this hypothesis is that if a species has achieved truly high intelligence and advanced technology, it may by design not have left any traces. Not because of modesty but because long-term sustainable existence actually required being light on environmental impact.
Changing your environment at planetary scale and breakneck speed is not necessarily the pinnacle of intelligence, certainly not if you have manifestly not yet understood all its intricacies, interdependence etc. A lack of understanding coupled with aggressive random interventions may even affect the very survival of a species.
The downside of the deep-sea tree-huger cephalopod scenario is that it is even harder to falsify...
Well apparently their strategy to ensure survival didn't do too well since we're discussing an extinct civilization here.
Maybe they're "extinct here", because they just left.
BTW. this is actually a big theme in David Brin's Uplift saga[0]. Basically, you have all these alien civilizations, more and less friendly to each other, but bound by some common rules, some of which regulate sustainable colonization. This includes an exclusive right to settle and use a habitable planet with a biosphere for $whatever number of millenia, and after that time, the civilization there is supposed to pack up and leave, fix environmental damage, and erase any trace of their existence, commonly achieved by dumping everything into the planet's subduction zones so it gets naturally recycled; after that, the planet is to lie fallow for ${some other number} of millenia, to give nature a chance at creating more biodiversity and stuff.
Quite ingenious setting, if you ask me.
--
[0] - https://en.wikipedia.org/wiki/Uplift_Universe
Not necessarily. They could have existed hundreds of millions of years ago, and become victims of the Chixhulub asteroid impact or other huge natural disaster after successfully maintaining an advanced civilization for hundreds of thousands of years, FAR longer than our probably ill-fated civilization has managed. They might have also left the planet. Or they could have transcended into energy beings.
There are >1 ways for a civilization to become extinct.
Another intriguing possibility is some sort of senility setting in after long-term evolutionary success. The intelligent cephalopods eventually got tired seeking answers from a mysterious Universe and settled for the quite life.
We aren't doing that well either. Too early to tell. But I think we've shown enough problems to at least speculate on how we will do during the coming 'great filters'.
"This is what de-growthers actually believe."
Maybe they used plenty of the under-your-tentacles fuel sources, but it's been a very long time since, and it's hard to tell.
https://en.wikipedia.org/wiki/Geologic_time_scale
More tantalizing, maybe there's a universe-level Silurian analog where our Big Bang was predated by another universe teeming with intelligent life.
Maybe we get Silurian'd ourselves.
For those unaware, the PETM was a rapid increasing in global temperature (and CO2 concentrations) around between 60-50 million years ago. This lead to a minor (on a geological time scale, major for those creatures living through it) climate crisis.
The cause for the rapid increase in temperatures at this time is still the subject of deep debate and largely unknown. However how very "out there" hypothesis, not even mentioned on the wikipedia page, is that this could have been when a civilization such as our experience an event more-or-less identical to our own current climate crisis caused by the rapid use of hydro-carbons.
Of course, the biggest challenge with this hypothesis is, as pointed out in the article, a civilization like this would not leave a trace on the geological record. So there's really no reasonable way to have much evidence in favor of this possible explanation.
But since here about this I've been fascinated by the problem of sending messages to the future. Suppose we come to realize that rapid use of hydrocarbons does most certainly lead to the destruction of any civilization foolish enough to tread this path. The most reasonable focus of scientific effort that would be to figure a way to warn the next advanced civilization on this planet in hopes they might not meet the same fate. But presuming that civilization is 50 million years in the future, how could this be done?
0. https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Therm...
1. Genetically modify as many wild plants and animals as we can to have a message encoded in their DNA, and release them back into the wild.
2. In areas that we expect to be geologically not much changed over the next 50 million years arrange concentrations of long lived radioactive materials in patterns that are obviously not natural. Encode a message in those patterns.
3. We could probably do something on the moon with nuclear weapons that could make a long fairly straight trench or series of parallel trenches that would be visible in telescopes and either be obviously non-natural or at least interesting enough to get them to go take a look.
Leave millions of metal spheres, cubes, tetrahedrons, octahedrons, dodecahedrons, and icosahedrons there which contain messages inside.
Google is telling me that any given spot on the moon gets hit be a meteoroid of ping pong ball size or greater about every 1000 years, so many of the messages will likely be destroyed over 50 million years, but maybe enough will make it.
BTW, is meteoroid the correct term? That's what Google's summary used and according to the dictionary definition as a small body that would become a meteor if it entered the Earth's atmosphere it would be correct but when we are talking about impacts on other planets or moons I'm not sure we should restrict meteor and meteorite to just meteoroids that are in or have hit after passing through Earth's atmosphere, respectively.
Anyone deciding to write scifi based on this, try to involve Romans somehow: https://en.wikipedia.org/wiki/Roman_dodecahedron
> a civilization like this would not leave a trace on the geological record
Am curious: if dinosaurs can be found with intact skin [1], after 110 million years, why not remains of the civilization's "people" (bones etc.) after 60-50 million years?
1. https://en.wikipedia.org/wiki/Borealopelta
Or maybe we _did__ find their remains and just have no idea they were part of an intelligent civilization. I mean, that's not a question any respectable researcher would be inclined to raise in the paper about the discovery...
We should have seen signs of similar non-uniform usage in the strata from before that time period. I wonder if any research has been done on this.
And all the byproducts of this use. We are leaving abundant traces of our existence basically everywhere. We can see it in the ground, in the seas, in the ice caps. Our existence will be very obvious to anything caring to just dig for quite a long time.
Would they have been using the same deposits we are suing, or would new deposits have formed over the last 60 million years?
Or could they have depleted their own, but what was un-usable 60 million years ago, have become usable today. Like something that was marsh land 60 million years ago, be coal today?
https://en.wikipedia.org/wiki/Carboniferous
Maybe some rings?
The problem I see is they either had to use sustainable hydrocarbons (so, carbon-neutral) or they would have used up the fossil fuels we're currently using.
At all? Like nothing that would be observable 50M years later?
Think about something you believe would last 50 million years. I am sure someone will be able to point out how and why that would just disappear after such ridiculous amount of time.
Wrong timescale though. 10000 years vs. 50 million. Millions of years is a very very very long time, our intuition is often wrong about timescales like that. For example a lot of modern land was still molten rock underground and vice versa.
To be fair, a species can achieve that without any intelligence or civilization whatsoever if they just manage to grow their population enough.
I think the most extreme species in that regard would be cyanobacteria, which changed the composition of Earth's atmosphere from methane and CO2 to oxygen [1] - and subsequently caused the metabolism of almost all other species to become oxygen-based.
This change is not just "detectable" today, it became the basis of most life on the planet.
[1] https://asm.org/articles/2022/february/the-great-oxidation-e...
And some threads from 2, 4, 5 and 7 years ago (did a pre-civilization discuss the possibility of a pre-pre-civilization?)
https://news.ycombinator.com/item?id=34755970
https://news.ycombinator.com/item?id=23654393
https://news.ycombinator.com/item?id=21840320
https://news.ycombinator.com/item?id=17899478
Possible to detect an industrial civilization in geological record? (2018) - https://news.ycombinator.com/item?id=38668884 - Dec 2023 (187 comments)
Silurian Hypothesis - https://news.ycombinator.com/item?id=34755970 - Feb 2023 (60 comments)
Did Advanced Civilizations Exist Before Humans? Silurian Hypothesis [video] - https://news.ycombinator.com/item?id=32837757 - Sept 2022 (1 comment)
Silurian Hypothesis: Were There Civilizations on Earth Before Humans? (2018) - https://news.ycombinator.com/item?id=23654393 - June 2020 (138 comments)
The Silurian Hypothesis - https://news.ycombinator.com/item?id=21840320 - Dec 2019 (52 comments)
Silurian hypothesis - https://news.ycombinator.com/item?id=17899478 - Sept 2018 (7 comments)
Deleted Comment
An alternative, possibly more optimistic (?) hypothesis: the first step of their civilization would be collective defense from large predators. Population concentrations would then make farming very advantageous. Yes, I'm more a scifi writer than biologist.
They develop large brains very rapidly, with lots of skills, BUT they don't pass on their skills, in part because they die quickly!
This article mentions that:
https://www.nytimes.com/2016/12/02/opinion/sunday/octopuses-...
Despite being mollusks, like clams and oysters, these animals have very large brains and exhibit a curious, enigmatic intelligence.
I followed them through the sea, and also began reading about them, and one of the first things I learned came as a shock: They have extremely short lives — just one or two years.
Other discussion - https://tonmo.com/threads/why-dont-octopus-and-other-cephlap...
---
Humans do seem to have some the longest life spans on the planet, and that's an important adaptation -- "grandmother hypothesis" and all that. I can see that generational knowledge is big deal, even in my own family, and in my coworkers' families.
Or you can look at the family of (ironically) Charles Darwin, with Francis Galton, and so forth
The outliers among primates move the civilization forward. So just having a few people with big brains, who absorb knowledge from their predecessors, is a big deal.
Though of course there could be some cephalopod species that evolved to live 100 years ... and then for some reason they disappeared, or lost that adaptation
Most of that is just using medicine and tools, as opposed to any purely biological longevity factor.
Octopodi be tasty.
The human package might be not much more complex than "start with a rock-throwing mob and features providing benefits"
So, on the surface, you could have a species that sprinted to all the features required for civilization - and then destroyed itself in a blaze of less-than-glory as we seem on a trajectory to do.
Edit: Note, I should add that I'd actually doubt this scenario could happen only because the evolution of human seems part of the general acceleration of evolution that can be seen throughout geological history.
It is interesting how we evolved all these necessary things pretty quickly, though if we look at other apes, they generally also possess opposable thumbs and binocular vision. Sometimes I wonder if there was help, such as a large, black monolith...
Now, that whole section is talking about modern cuttlefish, so I would agree with you regarding the author's hypothetical nautilus civilization.
First, spoken language isn't extraordinarily fast. Most of us here have experienced points in our lives where speech has seemed laboriously slow. Second, we have through much of recorded history, relied upon correspondence and the written word, where communicating a few sentences worth of ideas took weeks.
It is not outlandish to think that complicated, colorful shapes on the cuttlefish's back (pictures in the link, if you need a reminder) could convey an entire sentence' worth of information. With a refresh rate of what, 5 seconds? More than enough for human-speech-level speed.
Whatever other challenges they face, communication just isn't one of those.
(Eg, status is a form of mating, but we humans have so many tangential levels of displaying status that technology like a Lamborghini can become a mating signal, rather than using pure dominance. The combination of complex social behaviors and communication are necessary before the technology develops)
Vocalizations and their evolution were banned from discussion in the Royal Society because they did not leave a fossil record, so even meta-science was harder back then.
https://www.npr.org/2024/09/23/nx-s1-5120912/octopuses-and-f...
Octopuses also build colonies, using coconut shells and other tools.
https://www.newscientist.com/article/dn18281-octopuses-use-c...
https://www.science.org/content/article/scientists-discover-...
https://mashable.com/article/octopus-garden-colony-deep-sea-...
They can also solve human made puzzles.
https://journals.plos.org/plosone/article?id=10.1371/journal...
As for knowledge transfer, we know that they can teach other how to perform certain tasks. But beyond that, there seems to be a lack of research. Do they have complex language and can they transfer abstract “ideas”? My guess would be yes, but they communicate through color changes in ways that we have a hard time understanding. It seems likely that birds and whales have complex language, but we haven’t cracked the code on that even though their communication is much more like ours. Hopefully we find out some day.
https://www.scientificamerican.com/article/the-mind-of-an-oc...
https://www.forkingpaths.co/p/the-evolution-of-stupidity-and...
(I should add that there are some like Stephen Meyer who think certain abstract cognition is more magical and unable to come from basic evolution, but this has a theistic bent)
We are terribly preoccupied with tool use and physical artefacts as a defining factor of intelligence - anthropocentrism is of course pretty much inevitable, even when we talk of cephalopods.
In the context of civilisation, intelligence isn’t enough. Nomadic tribes are sapient, intelligent and have rich cultures, but they aren’t strictly civilisations.
The urban distinction is important because of economies of scale: pastoral societies are energy constrained. That doesn’t make them less interesting, again strictly speaking, personally it sort of does, but it does make them less powerful.
Within the Silurian context, the urban distinction is almost demanding: if humans stopped at Neolithic pastoralism, there is a good chance all evidence of our tool use would have disappeared within a few millennia, let alone millions of years.
Some pastoral societies have taken serious issue with this view
https://en.wikipedia.org/wiki/Mongol_Empire#/media/File:Mong...
Maybe but it's also because these things are evidence of cultural transmission - a thing for which there hasn't been strong evidence of in other species and people do look for it in other ways.
if the five senses can only percieve a fraction of that which they have been honed for over millennia, it's not unreasonable to wonder if there is much more to the world/earth than meets the eye, inaccessible and unintelligible to physical ape life or existing in ways we aren't equipped to percieve.
No matter what the other civilization looks like, that's how we've always reacted. It's almost a defining characteristic of our civilization.