[DannyB2]

If there were an industrial civilization here before us (modern humans) then it would be astonishing that in all of the fossils we have discovered, we've never yet discovered a single ancient nut, bolt, screwdriver, wrench, etc. Not one single wire or cast metal part.

As per the article, that civilization would have to predate all of the vast history of evolution that we know of. Wouldn't some higher life forms from such an earlier civilization have been in the fossil record?

[safety1st]

I think the argument goes that if the civilization was sufficiently old and short-lived, no we probably wouldn't find any fossilized evidence. For example we've only found about one dinosaur fossil per 10,000 years of dinosaur history. The dinosaurs were around for a long time, from 65-250 million years ago. Humans have only been industrialized for around 200 years. If you imagine a dinosaur civilization that's industralized for 1,000 years before it kills itself off, they still hung on 5 times longer than we have so far and yet we probably wouldn't have found fossils of their wrenches. (Not to mention that our archaeology is concentrated on places where humans lived which have little correlation to whatever might have been a good site for a dino city 100 million years ago.)

The authors of the Silurian hypothesis paper believe it's unlikely that there was an ancient non-human industrialized civilization. But they think if there was we wouldn't find its fossils. We might need to look for other markers like climate variances, radioactive materials or artifacts on the moon. Maybe some civilization arose, got stuck in the bronze age or early industrial tech for a thousand years, didn't generate those signatures, then died out. If our fossil record isn't thorough enough to find them then that possibility seems hard to disprove.

Wikipedia has a bit more detail on the Silurian hypothesis: https://en.wikipedia.org/wiki/Silurian_hypothesis

And the actual paper is here: https://www.cambridge.org/core/journals/international-journa...

[ethbr0]

In order for a civilization to be undetectable, you'd essentially bound terms in a terrestrial version of the Drake Equation [0]

You'd need a civilization that did not produce long-lived technological signatures (e.g. glass panes), that did not have a large number of individuals (i.e. produce remains), that did not substantially alter their environment (i.e. leave geographic markers), AND that did not consume easily available resources (e.g. oil/gas or metal ore).

Which is to say... possible, but not very likely.

[0] https://en.m.wikipedia.org/wiki/Drake_equation#Equation

[cubefox]

> For example we've only found about one dinosaur fossil per 10,000 years of dinosaur history. The dinosaurs were around for a long time, from 65-250 million years ago.

Dinosaurs presumably fossilize very badly compared to many artificial artifacts, like buildings made out of machined stone.

[benj111]

But we don't have any evidence for anything approaching civilisation, fair enough humans have been industrialised for 200 years, but they've been building to that point for 10s of 1000s of years.

[colordrops]

Another argument goes that they transcending to technology and form beyond what we can comprehend, covered their tracks, and left us be because we aren't interesting or to avoid interfering in our development. Perhaps our perception through the 5 senses and an understanding of reality as a physical universe of spacetime is just a short phase between being an animal and being a multidimension being.

[mrangle]

Where are the tools that carved the high relief sculptures at Gobekli Tepe, around 12,000 years ago?

Where are the high relief carvings that predate Gobekli Tepe, which served as the skill development toward it?

For example.

And we don't need to go nearly that far back to notice lack of ancient metal that had to exist, given what it accomplished.

Metal disintegrates fast. Megalithic evidence, at minimum and across history, implies a woefully incomplete archaeological record.

[civilitty]

> Where are the tools that carved the high relief sculptures at Gobekli Tepe, around 12,000 years ago?

Mostly flint. It's a seven on the Mohs hardness scale which is harder than unhardened steel tools.

Archaic humans have been making flint tools for millions of years.

> Where are the high relief carvings that predate Gobekli Tepe, which served as the skill development toward it?

Where to begin? Abri Castanet 35 kYa [1]. Venus of Laussel 25 kYa [2]. Roc de Sers cave 17 kYa [3]. There are countless other examples - most of them don't event have wikipedia pages.

Oldest known engravings by an Erectus are about 500,000 years old so it's been in the family for hundreds of thousands of years.

[1] https://www.archaeology.org/issues/63-features/top-10/270-to...

[2] https://en.wikipedia.org/wiki/Venus_of_Laussel

[3] http://www.visual-arts-cork.com/prehistoric/roc-de-sers.htm

[ses1984]

You’re looking for evidence of a specific thing, which is not the same as looking for evidence of anything.

[EdwardDiego]

Serious question, do we know that metal tools were used for those carvings?

From what I recall, until iron/steel was invented, it was pretty much abrasion as bronze was not hard enough to chisel nearly every stone.

[hooande]

This assumes that their technology would be similar to ours. They could have used biological mechanical parts, made from plant or animal material. They could have had radically different theories of mechanics or construction that better fit the state of the planet at their time.

In general the statement "They couldn't have been civilized because they aren't exactly like us" limits what we look for and how we look for it.

[notahacker]

The statement "they couldn't have been civilized because they aren't exactly like us" is a straw man though

The actual question the article posits is "Could an Industrial Civilization Have Predated Humankind?", and so it seems logical to take evidence of industry as a starting point to answer that question. A mere couple of hundred years of human industry has moved vast quantities of matter about, created many new types of molecule, demonstrably altered the climate and filled sediment beds with objects far more eyecatching and likely to be preserved than the dinosaur feathers and skin prints and footprints we've found fossils of. An industrial civilization need not regard combustion engines as the most useful power source, prefer wheels to gliders or think straight lines look cool, but it does need to be characterised by some sort of industry.

A hypothetical species of dinosaur that spent its life writing beautiful poetry, studiously avoiding dropping its organic tools anywhere they might be fossilised and generally being content enough with its life to not try to remake the planet for its convenience might even be more intelligent and cultured than us, but it wouldn't be an industrial civilization.

[thrashh]

That’s possible that they don’t have the same materials as us but they would have the same problems.

Take plastic or metal. Their main draw is that they do not decompose or degrade. There are a billion problems that can be solved when you have a material that does not naturally degrade or decompose.

So even if this civilization did not use plastic or metal, I find it hard to believe they didn’t come across a problem that needed a stable non-self-destructing material, which would then have been left behind for us to discover now.

It’s not feasible to build anything advanced if all your materials naturally decay.

It’s true that there are fewer decomposing organisms the farther back you go, but you have to go way way back to a point where the chance of intelligent life existing is pretty low.

[AtlasBarfed]

Eh, industrialization is heavily dependent on metallurgy.

What is the word industrial? Metallurgy, mass production, interchangeable parts, and the steam engine. Materials, tools, efficiency techniques, and energy.

The other aspect of industrialization is the sheer scale of it.

Honestly the only thing that comes close IMO is a lot of the cellular mechanisms. It uses materials in novel ways, efficient protein devices, and ATP energy. But I don't think it would scale to macro levels.

Maybe you could squint and look at ant/insect colonies?

[dheera]

Maybe, but on a planet that's full of rocks one would think they would have at least organized a FEW of the rocks into structures of sorts.

[fuzzfactor]

>"They couldn't have been civilized because they aren't exactly like us"

Well if you go back to the dawn of Homo Sapiens that's quite a ways back, but then you could rearrange that concept to say "they couldn't have been that uncivilized because they were exactly like us."

Oh, wait a minute . . .

[SiVal]

If they were so advanced that they left the ordinary material world behind, then anything is possible. Otherwise, they would probably be like us in the sense that their in-use technologies would span every level from lowest to their own highest. As our tech improves, we continue to use the wheel and shaped stone and conrete, iron, steel, glass, knives, ceramics, etc. We still use things that are pulled out of the ground (like our distant ancestors) while also using the latest AI algos.

So, a very wide range of "industrial civilizations" would be expected to leave behind lots of basic natural materials in artificial forms. Their basic natural materials would be about the same as ours because they are found in nature and not very diverse (compared to high tech pharma chemicals or digital algos), so we ought to be finding lots of evidence of pre-human low(ish) tech, even if they were quite high tech.

[andsoitis]

> biological mechanical parts

What’s that?

[marginalia_nu]

To be fair, there are entire human civilizations we know have existed that we barely have archeological evidence to make sense of. We know they had language, culture, technology and we've found shells, bones and rubble.

That, and the fact that we've found one antiktythera mechanism and nothing like it before or since raises questions. It seems implausible for a culture to produce a singular advanced mechanical computer with no precursors and then stop and never make anything like it again.

[giantrobot]

> It seems implausible for a culture to produce a singular advanced mechanical computer with no precursors and then stop and never make anything like it again.

A culture didn't create it. A person or team created it. The Antikythera mechanism was built before the ISO 9001 specification so its documentation may not have survived long past its creators lives. The high precision manufacturing required, in an era before high precision was all that precise, suggests the mechanism was likely a rare artifact. It was dumb luck it was found in the first place.

There's likely many complicated ancient devices lost to time because they weren't widely available or described in documents that have persisted. You literally run a search engine for marginalia that may not be popular or widely known. It wouldn't take much to knock a lot of that content off the web and be lost to history.

[tyg13]

To the contrary: the fact that only one ever was found, to me, suggests that it was the work of one brilliant mind whose work was not understood or continued by their culture.

[BuyMyBitcoins]

I figure that any industrialized civilization would have left indirect evidence of itself by mucking up the fossil record with introduced species. We intentionally and unintentionally introduce plants and animals far outside their natural range.

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

You would see some species inexplicably take on a worldwide distribution, or see species suddenly turn up on far away landmasses with no good explanation.

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

The link above is fascinating, but I do not think it is evidence of any past civilization. This probably happened naturally, but it does seem exceedingly rare. If there were a past industrial civilization there would probably be tens of thousands of examples like this one.

[naasking]

How many introduced species are there as a percentage of all existing species? This seems like an important number to calculate the probability that we might have missed such an introduced species given the fossil record we have.

It could also be that introduced species are less likely to be found in the fossil record for whatever reason.

Then again, maybe we have found such a thing but haven't recognized it for what it is due to missing context.

[SubiculumCode]

Interesting thought. However, one of the ideas that the article brings up is the extreme undersampling problem of fossil records. Its conceivable that a 300 year blip->catastrophe would be missed entirely in the fossil record.

[tetris11]

> You would see some species inexplicably take on a worldwide distribution

Im reaching here, but: https://en.wikipedia.org/wiki/Cat_gap

[redandblack]

Obligatory Pratchett reference - https://en.wikipedia.org/wiki/Strata_(novel)

[greatfilter250]

> worldwide distribution

Why does an industrial civilization need to be global?

Our industrial civilization appeared extremely quickly, perhaps in the past 300 years, but it happened to appear within a preexisting global trade and travel network. An industrial civilization which existed for a few hundred years, outside the context of such a network, might not ever see the need for one.

[ElFitz]

I recall someone asking on World Building StackExchange what aliens could find in a few tens of millions of years or so if the human race were to disappear today [0].

The answer was "not much", aside from discrepancies in metals distribution, with intriguing concentrations of iron oxyde, nuclear waste, or gold.

I am aware it certainly isn’t the most scientific or authoritative of sources, but they made interesting points.

[0]: https://worldbuilding.stackexchange.com/questions/117267/hum...

[pvaldes]

> What aliens could find in a few tens of millions of years

Much more than we are finding. The earth would be a mess with plenty of really puzzling events.

Wild tomatoes with narcissus and flounder genes for example.

Sudden extinction of entire groups of animals and plants in only a few thousands of years

Radioactivity holes and missile holes fossilized with metals in the bottom

Cities, and cemeteries in particular, would be a geological nightmare waiting for an explanation. A collection of grey granite from Canada carved in lames of uniform thick, polished for no reason and accumulated in a point. At 20 meters away another set of lames of Chinese black granite and 30 meters away a lot of yellow marble only known from Italy. All wrapped in asphalt, gravel, glass and concrete. Dumpsters would also be very strange places with plenty of plastics and chemicals that shouldn't be there.

Gems also. Diamonds carved in impossible shapes all ending in a more or less conical tail in the whole planet. Lots of things shaped like a heart. Strange collections of elements with unique properties of the periodic table found always together: Mixed minerals found near, gold, silver and platinum, at tens thousands of Km far away from its known mines. As they are often saved in fireproof boxes, would had survived miraculously in burnt areas.

Implants. Titanium fossils shaped like the femur of an animal (and always the same animal) and porcelain teeth would be enough to show a civilization and signal us in charge of it.

[defrost]

As of last Tuesday, the mark of human indistrial and technology activity on Earth is officially marked in the geological layer:

Welcome to the Anthropocene, Earth's new chapter (phys.org)

https://phys.org/news/2023-07-anthropocene-earth-chapter.htm...

    Since 2009, a cloistered band of hard-rock geologists and other scientists have toiled on a mission of great consequence.

    On Tuesday they will deliver the last of their findings—the location of ground-zero for the Anthropocene, the proposed geological epoch borne of humanity's outsized impact on the planet.

How the weight of the world fell on one geologist's shoulders

https://phys.org/news/2023-07-weight-world-fell-geologist-sh...

    Zalasiewicz pointed to an "embarrassment of riches" of evidence locked in ice cores, sediment and coral skeletons: microplastics, forever chemicals, traces of invasive species, greenhouse gases, and the fallout from nuclear bombs.

Proof humans reshaped the world? Chickens

https://phys.org/news/2023-07-proof-humans-reshaped-world-ch...

    When aliens or our distant progeny sift through layers of sediment 500,000 years from now to decode the Earth's past, they will find unusual evidence of the abrupt change that upended life half-a-million years earlier: chicken bones.

reply

[JackFr]

One hundred million years is a long time for a screwdriver.

[getmeinrn]

Random thought, but if we extrapolate the path we're on in terms of biodegradability and sustainability, it's not ridiculous to assume that a very advanced version of us would have developed the technology and legislation to ensure that all products biodegrade safely within X years.

[blueflow]

This doesn't undo all the stuff that already is in the ground and rivers everywhere.

[mc32]

And retroactively apply that technology to all the previous garbage they produced and their predecessors produced too?

Sounds like they invented the magic wand.

[markus_zhang]

The only possibility is...they sank into deep ocean. But then it's going to very unlikely that nothing surfaced for the last 20k or so years. So you have to throw a valcano or a large meteor on top of them, which would require even more proofs.

[mrangle]

There are megaliths under water, off of the coast of Israel. Not natural rock formations that look like such, but confirmed and clear megaliths of the rock circle type that is all over Europe as well as in Israel and elsewhere in the Near East.

[tarikjn]

Not pre-human but challenging the understood modern human timeline of industrialisation — We have not found the tools, but we may have found the products; in the form of stone-based vases that archeologists attribute to the Early Egyptian Period but are believed to be from much earlier, and would have required tools that have not been discovered yet. The channel UnchartedX make a compelling argument about this hypothesis: https://youtu.be/ixTTvRGk0HQ

[AlotOfReading]

What a silly video. The argument he's making is called a unilinear teleology. History is not an arrow-line march from less advanced to more advanced, and it's incredibly common for the apparent workmanship of artifacts to "regress" as styles and intentions change over time. Just look at all the people who complain about modern art because "classical takes more skill".

Also, there's essentially nothing you can't do with stone given primitive tools, sand, and a shitload of talent/time. One thing about ancient people is that they had all of these in abundance. Making arguments from the position of "they couldn't have done this with the tools they had" is almost always wrong because it's coming from a modern perspective of how tedious and uneconomical it'd be to do it today.

[lumost]

Pre-history is tough. Outside of written accounts and a few major cities cited in particular environments - there isn’t a lot of evidence about what humans were doing for 100k years before the Roman/Chinese empires formed. Even Egyptian history is pretty spotty.

We know there were civilizations in North America such as the Mississippi River valley mound builders - but our knowledge tops out at “they existed”. It would not surprise me if agrarian civilization rose and fell multiple times due to climate change.

[WalterBright]

I recall TV shows saying that the Egyptian pyramids could not have been constructed with Egyptian technology, so it must have been space aliens. The same for the closely fitting stones in Inca buildings.

It doesn't take advanced technology to do either of those things.

My favorite one was pi is there in the relationship between the pyramid base length and its height, and the Egyptians had no notion of pi. Again, space aliens! But if the Egyptians used a wheel 1 cubit in diameter to mark out the base, and the height was in cubits, then there's pi.

(What's a cubit?)

[FollowingTheDao]

You were assuming that their industrial civilization would look anything like ours. Why do they need nuts and bolts? Why couldn’t they have use some natural form of biodegradable materials?

[RecycledEle]

I would not say there has never been a single ancient thing discovered. There are many anomalous findings in archeology.

Here are a few examples: * https://en.wikipedia.org/wiki/London_Hammer * https://en.wikipedia.org/wiki/Coso_artifact * https://en.wikipedia.org/wiki/Nazca_Lines * https://en.wikipedia.org/wiki/Yonaguni_Monument * Parts of the Egyptian Pyramids seem to have been cut with circular saws. * Places in the ancient world seem to have been nuked, including the ancient city of Sodom. * Some ancient maps are amazingly accurate, when they should not have know the shapes of land masses.

I'm NOT saying any of this proves the Silurian Hypothesis. I looked into some of these claims, and realized how hard it is to be an archaeologist. The amount of stuff left behind is small, and you can never be sure who did what to it over the centuries.

Artifacts are not stored in hermetically sealed containers until archaeologists dig them up. Instead, artifacts mix with their environments for centuries. This mixes up the carbon and makes carbon dating iffy at best.

I classify archaeology as a pseudo-science.

[tanuki]

Aren't there lots of testible hypotheses in archaeology though? I get that you're saying that a lot of explanations feel speculative, but it feels a bit far to say the field itself is incompatible with the scientific method.

[MR4D]

If it were more than 65 million years ago there would be no evidence due to plate tectonics destroying all evidence. Still could be on the moon or another planet though.

[Barrin92]

There would be no evidence on the surface of the earth, but just as there's characteristic fossil layers in the ground there would be evidence in the sediment. Right now about 30 billion tons of concrete are used by our species every year. If there were industrial civilizations of that scale, you'd have a whole stratum of very obvious artificial origin between the rocks.

Also some leftovers of the nuclear industry. Enriched Uranium does not occur in nature but U235 has a half-life of about 700 million years. So remnants of our nuclear activity will be detectable for a long time.

[flangola7]

We have fossils of cyanobacteria from 3 billion years ago. There's plenty of dinosaur fossils that are 100+ million years old. We definitely could have found something.

[paulryanrogers]

We still have fossilized bones that old and older. And even if they had corroding tools there would likely be cast fossils proving their existence.

[barelysapient]

I like to wonder what undiscovered fossils exist below the oceans that cover 70 percent of our planet.

[blueflow]

Look up about continental vs ocean crust, ocean crust is younger and has a shorter lifetime. You have better chances finding maritime fossils on land.

[mc32]

It's one of those "prove a negative" but with the enthusiasm of flat-earthers. Is it technically possible there could have been an isolated population that evolved and emerged and then got engulfed by a supervolcano or was taken under by a sudden asteroid impact or ... and all traces erased? We can think and work out such scenarios, but they are not likely at all.

[jboogey]

A great Atlantic article explaining how current human civilzation might appear in a fossil record in the distant future https://www.theatlantic.com/science/archive/2019/08/arroganc...

[zakki]

OOT but same vibes, this same reasoning is used by Creationist as well. If evolution happened, why don't we find more and more fossils of the intermediate form? Until now we only found final result of the evolution. And some hundred million years animals still exist, i.e. Coelacanth.

[IAmGraydon]

Not sure what you're talking about here. There have been many thousands of fossils found at various stages of evolution. Human evolution alone has a wealth of examples, and this is not new:

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

[coredog64]

There’s a Sci-Fi series that explores a technologically advanced ice age civilization that built with water/ice and hydraulics. The current protagonists couldn’t figure anything out because all that was left was tiny bits of corroded metal.

[SubiculumCode]

The article indicated that surface turnover could have removed that evidence.

[topspin]

And yet we have 3.4 billion year old cyanobacteria fossils.

[Mountain_Skies]

If that were the case, perhaps someday we will find evidence on the Moon or elsewhere in the Solar System that an earlier civilization achieved space flight before they were erased from Earth and unable to establish a permanent foothold elsewhere in our corner of the cosmos. The Moon and other celestial bodies in the Solar System of course have their own processes that erase the surface over time, but at least with the Moon, it does appear to be a far slower process.

[Simon_O_Rourke]

Lets not forget all their detritus and trash too - as well as any industrial waste... that stuff would have shown up long long ago if it in fact existed.

[analog31]

Any such civilization would have to have been configured to leave no traces for us to discover. Russell's Teapot comes to mind.

[thrashh]

That species would have to be completely united and able to collude without a single disagreement.

Not only that, they would have had to achieve complete perfection because we haven’t found a single trace.

[pragmatic]

Read the article.

[ekianjo]

What do you know about the preservation of metal in fossil layers over millions of years?