Silurian Hypothesis | Hacker News Reader

Silurian Hypothesis

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119 pointshosteur60 comments

Without having read the paper, my first counterargument would be like this: Yes, fossilization is rare. But industrialization is a wildfire. A spezies undergoing this would multiply like crazy and there would soon be hundreds of millions of the same exact species around. That's just talking steam power. Going to space? Hard to believe they'd achieve that without reaching a billion or more. Assuming similar productivity of course.

Hundreds of millions, much less a few billions individuals of the same exact creatures living and dying would lead to a rather distorted fossil record, wouldn't it? Even if they used cremation, they should still be distorting the fossil record just from those bodies that "fall aside" somehow. Also because they'd need domestic animals and they'd kill off or supress other macrofauna. They would have to be giant squids to not leave behind MUCH of a fossil record, and then survive against the biggest and baddest dinosaurs...

It’s true that only very few individuals would be fossilised and fewer if they found. Nevertheless we do generally find multiple fossils of the same or closely related species. We also find fossils of multiple stages in the evolution of many species. So it seems unlikely to me that we would find zero fossils of a species advanced enough to colonise the entire planet, as we have, nor any of their ancestral species.

It also seems likely that technological artefacts would leave fossil-like impressions, or for mineral objects like ceramics simply straight up survive in strata. Such artefacts would massively exceed the number of individuals and trash has a tendency to get widely distributed so it seems extremely unlikely none would be found.

One idea is that they might have only lived in a small geographic region such as an island, and if that location happened to subduct and not reach the surface we’d never find them. Well yes, but the major advantage of technology is that it allows you to overcome geographic and climatic barriers, which is why us hairless tropical plains apes have colonised every region on the planet, and did so everywhere except Antarctica but including the arctic with Stone Age technology. An industrial society would also create demand for resources, prompting global expansion.

So it’s an interesting thought experiment, but I just don’t see how the hypothesis is really viable. Not impossible perhaps, but extremely low likelihood to the point of implausibility IMHO.

I do agree that a society capable of nuclear power or space travel can be considered implausible. A similar thought experiment might be, "how technological could a prior species have become before we'd notice?"

Animals today, from dolphins to chimps, can be found using tools. Is there any reason to believe this didn't happen in the age of the dinosaurs? Then you can expand beyond simple sticks and stones to other primitive technologies. Maybe we weren't the first to figure out fire, or agriculture, or animal husbandry.

Or maybe any brain capable of fire + agriculture + animal husbandry will eventually be so successful that nuclear power and space travel are inevitable.

I'm not arguing in favor of any of this: it's just fun to think about.

In my will, I'm going to ask that I be buried in soft mud in a river delta, or some similar place likely to become sedimentary rock in the far future. But I also want to be buried with some relic that proves I was a member of a technically literate civilization. I surmise something like a wooden abacus. The wooden abacus would fossilize along with my remains. I hope my fossil, and the fossilized object I carry, will be found in the far future.

Cynically, with how much trash there is around rivers you're likely to be fossilized within a strata chock full of traces of our civilization.

Non-cynically, I would recommend having a stone abacus crafted if you wish to be buried this way - effectively mineralize the relic manually and don't leave its fossilization up to chance. You could also try encasing some objects into amber or resin and scattering them around your final resting place.

The distribution of fossils between continents was one of the pieces of evidence used to support the hypothesis of continental drift and plate tectonics. It would make sense that any prior civilization would also be introducing species outside of their native ranges, or making several species show up in disparate parts of the globe with no good natural explanation. https://en.wikipedia.org/wiki/Columbian_exchange versus https://en.wikipedia.org/wiki/Great_American_Interchange

This species is particularly fascinating because it is only found in Japan and parts of Texas. No one has a good explanation for why, although no one is suggesting an ancient civilization did it.

https://en.wikipedia.org/wiki/Chorioactis

A fun thought experiment is to imagine what we will do once we leave the cradle of Earth behind. Will we just leave all of our junk here? Make the homeworld a monument to our past? We would know that it wouldn't last, everything decays with time so some would argue it would be a crime not to preserve it and the only way you can be sure to preserve something is by regularly tending to it. I imagine many would argue that we take all of the most valuable artefacts with us, keeping them in pristine condition and on display. This sentiment might even extend to our dead, why leave them to be ground to dust by the uncaring aeons? Inter them in gigantic space crypts instead. Further, we may be determined to leave a pristine planet behind for the animals that still reside there and, eventually, for the next species to crawl its way up to sentience. Jeff Bezos has expressed a wish similar to this for our future. Move everything into space and keep the Earth as a giant nature reserve. Hundreds of years from now perhaps we will do that and after that maybe we will even leave the solar system behind us as we strike out into the universe. Now cast your mind back tens of millions of years and imagine some other intelligent species doing the same for us.

> A fun thought experiment is to imagine what we will do once we leave the cradle of Earth behind. Will we just leave all of our junk here? Make the homeworld a monument to our past?

It is a fun thought experiment, but humanity is big. Humanity leaving Earth would be extremely more likely to look like a few people hopping on a ship and flying away and everything else stays the same.

For it to look anything like "last one out, turn off the lights" type of thing, energy would have to be truly free and there would need to be a _very_ compelling evacuation scenario. Otherwise there would be a lot of people left behind for social/economic reasons or because they just don't want to leave.

It's all about incentives. A huge percentage of the human population has decided to live in cities because they offer a variety of incentives to live there. The transformation isn't complete but if the benefits were even greater then you could eventually see a complete shift.

Who knows what incentives a hyper-advanced civilization might have? Maybe life in space is a million times more appealing than life on a planet for a sufficiently advanced technology level. If estimates are to be believed then the resource wealth of the solar system far exceeds anything contained within the Earth. If you've solved the problems of efficient space propulsion, resource extraction and construction then you would have access to an abundance of everything you need. Space also has a lot more space, enough room for any person or group of people to build whatever they want without annoying their neighbours. It also has more energy both in the form of sunlight and radioactive elements. So yes, maybe energy and matter are nearly free for a true space faring civilization and maybe that's the reason no one would want to stay behind or at least so few that they would leave very little evidence of their presence.

So this article: https://www.science.org/content/article/most-species-disappe...

says that of modern threatened-but-not-extinct mammal species, we have recorded fossils for 9% of them. For non-threatened extant mammal species, we have recorded fossils for 20% of them. Assuming that's correct, it doesn't seem crazy to imagine that we might not have fossils for a species or it's say 5 ancestors species that existed let's say 10M years ago -- fossils are also subject to being broken or subducted and so we would expect recent species to leave a greater fossil record. And being an intelligent, cultural species may reduce the chance of fossils being formed for high populations, due to death practices.

We do find for example many different fossils for say triceratops. But that shouldn't be taken to mean that we find lots of different fossils for every, or even most, species extant at the time of the triceratops.

Considering an extant species is like picking an arbitrary point in the existence of a past species, and excluding all fossils formed after that point. On average that half the fossils. As for threatened species, just a guess, but I’d expect most of those to be likely have relatively small populations to start with and live in constrained habitats, all factors that would tend to mean they would leave a lot fewer fossils on average anyway.

A advanced technological species would need to exist in huge numbers to support a developed economy. Id expect them to colonise widely. Also I’d expect artefacts to exceed individuals by probably a handful of orders of magnitude.

I think you're dramatically overestimating the likelihood that artifacts would survive in recognizable form for millions of years. I do think we can be reasonably sure that there was no advanced technological society let's say 50,000 years ago. But 20M years ago is another story. 5M years might be another story.

Whether you'd find fossils of an advanced technological species at a point in their history when they might have a population of billions seems incredibly contingent on unknowable things about their culture. But the question of whether you'd find fossils of them from their prehistoric period (in which their population would not necessarily be enormous), or of their evolutionary ancestors seems less contingent, and very plausibly you wouldn't.

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)

I wrote a novel, I know, every asshole has. About this. My theory, that is, either ridiculous or correct, the Silurians are the ancestors of the dolphin. The dolphin, or OK, the Orca, have a larger cerebral cortex than humans. What if, they were on once land dwellers, could it be? There is some science behind that. And say, they burned a bunch of hydrocarbons and caused a global warming, melted all the ice and they had to evolve to be ocean mammals.

I understand this is a sci-fi fantasy.

But my mind wanders, I think, let's say you understand your fate, once cast, how would you warn the next intelligent species to inhabit Earth?

You cannot simply place an odalisque with an inscription on it, of course, over the millennia or billennia, it will be erased, you send out a sentinel into space.

How would you warn the next iteration of intelligent life?

Perhaps some sort of AI space craft?

What if it turns out, they are the intelligent ones, having learned a lesson we have yet to learn?

Dolphins, as mammals, descended from a land-walking mammal discovered in Pakistan.

As did the whales.

https://en.m.wikipedia.org/wiki/Pakicetus

https://www.nhm.ac.uk/discover/when-whales-walked-on-four-le...

"Pakicetus, a goat-sized, four-legged creature that scientists recognise as one of the first cetaceans (the group of marine animals that includes dolphins and whales). [Discovered in 1981.]"

https://www.amnh.org/explore/news-blogs/on-exhibit-posts/the...

(I actually saw this in an aquarium/museum exhibit a few weeks ago in Clearwater, Florida.)

>place an odalisque with an inscription on it Besides being cruel, odalisques aren't known to exist for more than a hundred or so years. Let alone millennia.

What if the more difficult to explain parts of the UAP phenomenon is our experience of the remnant of that previous civilization? It never went extinct, it just moved into space and the bottom of the oceans. We're ants, unaware of the civilization that surrounds us because it is to alien/advanced for us to comprehend.

Spoilers for Robin Cook's Abduction. Fun read.

> place an odalisque with an inscription on it

obelisk?

> I’m sure the OP meant obelisk, and probably typed that originally, but it looks like their system changed it to odalisque, "a female slave or concubine in a harem, especially one in the seraglio of the Sultan of Turkey."

It’s funny how autocorrect changes real words to other words. Obelisk seems more common than odalisque so maybe OP just writes about odalisques quite a bit.

Have these people not seen how much garbage we leave lying around!?

A lot of artificial materials last far longer than natural materials. Pure metals especially can last a very long time, like gold jewellery, or even just aluminium.

Not to mention "forever chemicals", large scale concrete construction, mining, etc...

We'll be finding evidence of our presence on Earth for a billion years or more, whether we like it or not.

Most evidence would be gone after a few million years. Any metal that oxidizes would go first, aluminium included. Concrete would disappear with weathering, earth quakes, and even just by the action of plants. Huge open pit mines or mountain top removal would be weathered away and filled in with sediments. Plastics decompose and chemicals are diluted and dispersed or consumed by microbes. Gold jewelry may last a long time in the right conditions but if it's subject to any kind of motion it will deform and wear away since it is much softer than the grains of sand that would be rubbing against it. Everything would end up buried under layers of sediment or higher sea levels or even subducted into the mantle and melted.

We’re finding organic remains like skeletons hundreds of millions of years later! Manufactured goods made of durable materials would certainly be just as easy to find. It’s simple logic.

We find _extremely few_ organic remains that got ungodly lucky and are still recognizable after so long.

Most "durable" goods are durable only on human scales of time, and if anything are less likely to survive on longer time scales.

A word of warning: a few years ago, the related page at https://en.wikipedia.org/wiki/Out-of-place_artifact took me down one of the worst Wikipedia procrastination rabbit holes I've ever lost myself in.

If you enjoy that kind of thing then you might like Terry Pratchett's early SF work "Strata" that riffs heavily on this idea (on a less parochial scale) while also enjoyably sending up Niven's Ringworld and a few other tomes.

There is also 2022 Netflix series "Ancient Apocalypse", presenting a theory that there was a civilization (not industrial, but like Romans or Egyptians) living on the coastal areas during last ice age, but their traces have disappeared now that sea level is 120 meters higher than during ice age.

https://en.wikipedia.org/wiki/Ancient_Apocalypse

In the same vein, I’ve heard historians theorize that Doggerland was the most comfortable area for human habitation in Northern Europe during its existence, with its lowlands, lakes and river systems perfectly matching the landscape of the other ancient civilization centers. The lands of the modern UK and Scandinavia were by comparison inhospitable highlands, where humans have moved after their ancestral lands were flooded.

See https://en.wikipedia.org/wiki/Doggerland and the episode of BBC In Our Time podcast on the subject.

I haven't seen the show, but I'm captivated by the idea that there are probably thousands of submerged sites like Cosquer Cave that hold traces of human history that are lost to both time and the sea. It's not on the same level as a city, but I am intrigued by it's existence nonetheless. It is also somber to think about how much artwork in that cave was washed away when it was flooded.

https://en.wikipedia.org/wiki/Cosquer_Cave

How kind of you to include a link to that very page with your post!

Relevant:

https://www.dailymail.co.uk/sciencetech/article-1096959/Myst...

I’ll just say it. The earth is around 4 billion years old. Due to the constant shifting of the surface and oceans, we don’t know what existed before. Fossils only form under very specific conditions. The Sahara for example were a forest before, so why haven’t we found trees and fossils there. What I’m basically getting at is, saying that we should be able to detect whether life existed by looking at sediment is speculation at best. Water and sand is extremely abrasive not to mention scavenger animals and insects that basically recycle waste. I’m not saying that there were advanced civilisations before us, but saying we’re are the first and only advanced civilisation that’s been on a planet for the last 4 billions years, is like saying there’s no intelligent life in the universe and earth is “special” because we can’t find alien life anywhere in our solar system.

There is a Kurzgesagt video on this subject.

https://m.youtube.com/watch?v=KRvv0QdruMQ

They just found stone tools from 3M years ago in Kenya, so I assume they can also find fosilized artifacts from that long ago. But the Wikipedia article says that's not likely. The claim that it is unlikely seems to be inconsistent with the evidence.

Doesn't the hypothesis concern the possibility of civilisations a lot older than three million years, though?

The dinosaur fossils are at least from 65M years ago! If there is evidence, we'd see it in the fossilized records. The 3M figure was for stone tools, which was unexpected, but still they showed up. Any evidence of the existence of an advanced civilization tens or hundreds of millions of years ago that coincides with the dinosaurs would show up in the fossil records.

I’m not an expert, nor even a well-informed layman, but my understanding is they argue that fossilisation is extremely rare, rare enough for a civilisation that may have only lasted a few hundred years to slip through unnoticed.

See, for example, https://www.nature.com/articles/d41586-021-00984-2 — only 32 adult T. rex have been found [as of the date of the article], even though the species existed for two million years or so.

Are they overstating things?

If you are looking for an in depth (pop-sci) dive into the mass extinctions in earth's history definitely check out "The Ends of the World" by Peter Brannen. It covers the five mass extinctions with a good mix of scientific detail and entertaining writing. IIRC it discusses the likelier explanations for Silurian extinctions including disruptions to the carbon-silicate cycle (volcanism -> fresh silicate rocks -> weathering removes CO2 from the atmosphere as ultimately insoluble CaCO3 -> global ice age), anoxia/CO2 drawdown caused by increased phosphorous and other nutrient availability, and others.

"The Ends of the World" stands out as a top disaster book along with Simon Winchester's "Krakatoa" and Sebastian Junger's "The Perfect Storm".

I'm reminded of the Reptites from Chrono Trigger. They ruled the planet when humans were still primitive; the arrival of Lavos wiped them out and allowed humans to flourish. But as it turns out, Lavos was "farming" humans as food for itself and its children...

Video on the topic: https://www.youtube.com/watch?v=lASPp9stEYA

The genius of this Silurian hypothesis and related ones is that they are theories of archeology where you start with an unfalsifiable premise, and then anything that fails to falsify it becomes evidence for the theory, hence "ancient astronaut theorists say 'yes'" I discovered that ancient aliens TV series just before the pandemic and have binged it as a kind of esoteric comedy, where every confirmation of the theory and their various hustles lands like a hypnotic joke. It's probably my guiltiest vice.

It is really plausible that ancient pre-cataclysm civilizations were so sophisticated that they used megalithic walled fortresses as a trans-solar biosecurity schemes, if you first accept the unfalsifiable premise that some proto-humans became spacefaring. It's brilliant.

I actually believe they're probably right in some coincidental way as well, but I enjoy the misdirection in the logic of their ideas because it's like a card trick. However, concretely, today there are two things we know: magic is a trick, and stories of parapsychological phenomena are not evidence of sophisticated extra-terrestrial life. The junk ideas challenge what other theories of everything we believe that are founded on similarly mysterious premises. Religions are fairly contained, but ideologies like the ancient astronaut theory evolve to incorporate whatever idea they encounter as new evidence of itself. Can you can do it for anything? "Ancient _X_ theorists say 'yes'"

It must be infuriating to some academic archeologists to get questions about aliens, but really, it's developing interest in the field, and I've probably said before that we could fund and promote a lot of real science by attaching entertainers to it. Not to go on, but AA is one of my favorite silly topics.

Not the same thing. This "silurian hypothesis" is not so much asking the question about the existence of a pre-human industrial civilization but rather to what degree we could rule it out.

It's a rather implausible proposition, after all, so it would take extraordinary evidence. And that evidence might not survive that long? But this doesn't make the proposition more likely.

Anyone interested in this topic might enjoy reading Forbidden Archeology by Michael A. Cremo. There are a lot of anomalies out there, and this catalog documents them well (so much so that there's an abridged version that leaves out the documentation).

I'm pretty sure this was also in The Science of Discworld earlier than 2018, where a few civilizations exist before and after the dinosaurs.

I am surprised this is not mentioned in Wikipedia, but I don't have the book around to be able to cite it properly.

So no alien king's treasure room full of solid gold tributes?

No alien cartoonist's frozen head floating in a diamond jar protected inside a nuclear powered vault?

Not a single phallic sculpture in orbit that is visible to the naked eye from Earth?

Yeah, right.

Kurzgesagt did a great video on this:

https://www.youtube.com/watch?v=KRvv0QdruMQ

Much like the Ancients from Stargate.

I don’t get what’s interesting here if I’m interpreting this correctly. Paraphrasing, I’m reading the Silurian Hypothesis to be: Geological activity would wipe out most evidence of prior industrial civilization, but we could find larger scale things such as geothermal taps or nuclear evidence.

I love how in HN, comments on some thread bring others to publish topics brought up on the comments in as new posts too

https://news.ycombinator.com/item?id=34734027

These are 'follow ups' in HN jargon and are typically moderated as dupes since they effectively behave the same way.

https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...

Whenever I see this I find it really annoying. Not to say it isn't posted out of genuine interest and desire to share, but it still rubs me the wrong way and has a karma whoring vibe. Maybe finding too many of these is an indicator one is reading HN too much

When discussing the fossil record it's astonishing that no one ever mentions the possibility that an advanced species would intentionally remove all geological and archaeological traces of its existence. Why would they do that, you ask? Well, quite possibly for similar reasons homo sapiens is currently doing the same thing! The environmentalist ideology holds that we must return the planet to a pre-industrial state, as much as possible, and to leave as few non-degradable artifacts as possible. The movement would achieve success precisely when there is no evidence left that humans ever existed.

If we can't detect previous advanced civilizations, I think it adds more evidence to the simulation hypothesis. Why would simulation designers include ancient nearly-undetectable advanced civilizations? Why don't video game designers fully model and texture areas of the world that aren't accessible?

If we were living in a simulation, I think it would be programmed in such a way that it would be emergent. A bit like a mandelbrot set, where the rules are simple but the complexity is infinite. No need to texture anything if the rules define what the texture would look like by a minimal fixed set of rules (laws of nature).

There’s a part of me that kind of views this as a theological prospect—that God (or however you care to name the supreme being, as such) is constantly upping the challenge for us as humanity.

To me, it would be more interesting to design specific scenarios to study.

> it would be more interesting to design specific scenarios to study

The weakness, to me, in the simulation hypothesis is the ancestor simulation assumption. Most of our computing power concerns itself with the future. Not the unchangeable past. Hell, simulated universes with different physical constants would be far more interesting.

I know folks doing climate modeling - there’s extensive simulating the past, because it’s the only way for us to validate our models.

If you have the capability to run such a simulation, why not start from time=0 and just let it run... if you already have near infinite compute ability what does it matter? If you are an observer outside the universe so to speak does time even happen?

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