Lost Advanced Civilizations | Hacker News Reader

Lost Advanced Civilizations

overcomingbias.com

136 pointsheadalgorithm128 comments

From the OP: "On the other hand, we often hear reports of people uncovering old things that others had confidently predicted would never be found. Which makes many suspect widespread overconfidence in claims about what we know can’t be there, because if so we would have seen them already."

Hanson here appears to be backing up his claim with three hyperlinks. One thing that troubles me about rationalist-affiliated writing is that it tends to rest on what looks, at first glance, like a decent evidence base, but this evidence often breaks down under a little scrutiny. For example:

• Hanson's first link is to a recent National Geographic article that summarizes an archaeology finding from Bronze Age China. The summary is, IMO, misleading in one key respect. It calls the find "astonishing" because "parts" of the site "date back 4,300 years, nearly 2,000 years before the oldest section of the Great Wall—and 500 years before Chinese civilization took root on the Central Plains." The Great Wall reference is a non sequitur: it's a bit like saying that a find from the Old Kingdom of Egypt is astonishing because it dates back to two thousand years before the building of a Roman aqueduct. There's no real connection, and it's not at all news that agricultural civilizations existed in China circa 2300 BCE. Whether we want to call these societies "Chinese civilization" or not is debatable. But this finding, while really interesting and cool, is very different from what Hanson seems to be reading it as -- which is to say, as evidence for the belief that future discoveries might yield signs of "advanced civilizations" which far predate the Bronze Age as it's currently imagined. After all, in 2300 BCE, written records and urbanized societies already existed in a fairly large swathe of Eurasia.

• His second link is simply to the Wikipedia page for Göbekli Tepe. Which is a totally fascinating site, I agree. It certainly does have unique features, such as the megalithic carvings. But again, it is not evidence of an entirely unknown "advanced" civilization; instead, the people who built Göbekli Tepe clearly fit into the existing archaeological record relating to the Neolithic Near East. We've known for some time that early agricultural societies were emerging in the fertile crescent around the same time as this site. What's fascinating about this site is that it appears to predate agriculture in the region. However, it is thought to fit into a transitional stage ("Recent DNA analysis of modern domesticated wheat compared with wild wheat has shown that its DNA is closest in sequence to wild wheat found on Karaca Dağ 30 km [20 mi] away from the site, suggesting that this is where modern wheat was first domesticated"). So again, IMO this has nothing to do with his claim about "lost" civilizations which don't fit into our existing chronology.

• The final link is to a Nature write-up from two years ago relating to a contested claim about when humans arrived in the Americas. Again, this has nothing to do with evidence for an "advanced civilization" that has previously not been discovered.

All three of these links reference really interesting and important work which I very much hope continues to be funded and elaborated on. I'm convinced that there are incredible mysteries in store in the future, especially in the field of underwater archaeology. Yet to my reading, none of these reports relate to phenomena that scholars "confidently predicted would never be found." Any archaeologist or historian with a sense of humility will gladly admit that there are a huge number of unknowns in the historical record. None of this can be leveraged as a basis for the existence of "lost advanced civilizations" (by which he appears to mean agricultural or otherwise technologically-advanced civilization that far predate the Agricultural Revolution as its currently understood, and which were forgotten after some kind of hypothetical period of decline).

For that, you need what Hanson waves away: actual archaeological or historical evidence.

Hanson is very skilled at asking questions whose answers end up confirming his biases.

I follow him on Twitter. It's quite remarkable how he structures his frequent polls, and subsequently uses them to confirm his priors, when the limited choice of questions funnel responses into Hanson's favoured response vs a series of straw man positions, with no catch all "other" to gather disagreement even from the choir that follow him.

The best thing about him is that his dubious evidence does sometimes support an interesting perspective; it gives him ammo to stick to a possibly unpopular position, which might even be true, or have sufficient truth value to merit thinking about.

Overfitting, fast and slow.

But by your own quote, he is not presenting these as evidence of advanced civilizations. He is presenting these examples as evidence of "old things that others had confidently predicted would never be found".

Sure, but Hanson seems to be taking a stronger position here than "well maybe". He's proposing that we should set up prizes so people are incentivized to always be on the lookout for older civilizations.

Indirectly, that's the funniest part of his whole schtick. He seems to segment the world in two: things addressable by pure reasoning, and things that require doing something.

He treats the former as his domain and clearly sees himself as a master thereof. And the latter you solve with bounties.

The Critique of Pure Prediction Markets by Immanuel Köd (1781):

> "That all our knowledge begins with bounties there can be no doubt. For how is it possible that the faculty of cognition should be awakened into exercise otherwise than by means of payouts which validate our judgements, and partly of themselves produce rationales, partly rouse our powers of understanding into activity, to compare to connect, or to separate these, and so to convert the raw material of our sensuous impressions into a knowledge of objects, which is called experience?"

Edit: wow, what is SFW Rule 34 called? this is a thing. http://kenfeinstein.blogspot.com/2011/01/kant-on-betting-and...

Isn't he always on the lookout for older civilizations?

Right, and I'm arguing that none of these cited articles are valid evidence for that claim. Leaving aside the fact that his vague wording gives him enormous wiggle room, i.e. "others" could refer to anything from professional archaeologists to the Ancient Aliens guy and "old things" could mean almost anything.

A megalithic site, especially of that size, is the evidence of an advanced stone age civilization.

Surprisingly, one existed thousands of years before what was long considered the oldest, the Egyptian pyramid builders.

Uruk also predated the pyramids by a couple millennia and has been known for a pretty good while. Archaeologists also don't use the three-age typology (or the word "advanced" if possible) anymore.

The surprise of gobekli-tepe is mostly in demonstrating once and for all that monumental construction isn't limited to fully sedentary peoples and doing so in a way the diffusionists can't argue with.

This is why a I think it is a bad article. He first proposes some far-outlier theories, which need extraordinary proof as he acknowledges himself. He does not give it in the article which propels his theory in the realm of fantasy. His article would be way more honest if he would describe it as pure speculation, instead of shoehorning all kinds of finds or theories into his flight of fancy.

I mean it is a fantastical idea, and if we ever find a laptop from 10000bc I would be stunned, or if we find marsian burial chambers, but the probability just isn’t very high on what we observed sofar.

That isn’t to say a lot is lost to history, which skews our interpretation, especially prehistorical, but that would warrant a different kind of article.

You mean like https://www.theatlantic.com/science/archive/2018/04/are-we-e... which links to https://arxiv.org/abs/1804.03748 ?

For what it's worth, I was the ED of the Center for Applied Rationality for a couple years, and I have basically the same criticism of the culture. You could fairly summarize a lot of conversations I've had as "Your study sucks, and anyway it doesn't say what you think it says." I do think there are a lot of smart people who "rationalist-affiliated" who get this more right than wrong though.

That's what drew me to the idea of 'lesswrong'; an acknowledgement that we all kinda suck at this and your argument is almost certainly wrong in some way, but if we approach with good intentions and open minds, at least the arguments will be _interesting_.

LessWrong is another altar at which your worship should include a grain of salt. They have quite a lot of great articles but they often fail to do a sanity check when their conclusions become ridiculous. See also, the Roko's basilisk stupidity.

That is as true or more of every altar[0], so I'm not sure what your point is.

0: "Worship me without salt or die!" is a reason to engage in premeditated deicide, not worship.

Reading the articles it's very easy to get an impression that LessWrong is a "best of the best" community.

They are. But that's a very depressing statement about everyone else. About them it's more damning with faint praise.

> From the OP: "On the other hand, we often hear reports of people uncovering old things that others had confidently predicted would never be found. Which makes many suspect widespread overconfidence in claims about what we know can’t be there, because if so we would have seen them already."

What percentage of confident predictions about old things were eventually disproved (by uncovering old things)? Poor article with little data.

Have you guys checked out the episode on JRE with Graham Hancock? [0] They talk about the Bronze Age China and Göbekli Tepe. At the time I was seemingly convinced why the academic community wouldn't let these new theories flourish despite the archeological evidence. I was not aware of the work by Hanson so I can not comment on that.

A similar thread on HN in the past [1].

[0] https://youtu.be/aDejwCGdUV8 [1] https://news.ycombinator.com/item?id=23761252

I think you are taking those links as an overly important part of Hanson's argument.

His point is that if we consider where life originated without any a priori assumptions, Mars could be viewed (based on some existing theories) as a more likely place of origin than Earth.

He's simply peeling back some of the existing (and often immovable) theoretical layers that filter our perception of the underlying reality and asking whether any of those layers might be reasonably discarded.

In a way this is the same point made by Kuhn about the calcification and cultural embeddedness of scientific authority.

He then notes that we humans seem to have a bias in which we eagerly rule out explanations that turn out to be true, and wonders how we might overcome this.

He proposes a prediction market mechanism that would allow for probability-weighted odds-making while also allowing for profits to be extracted by those whose knowledge is not widely shared; in effect an incentive for structured investigative behavior toward answering a series of deep and related questions.

It's not that Hanson believes archaeologists lack humility, just that the questions that are considered most interesting and the analytical approaches that are the most culturally rewarded may result in a landscape that prevents us from understanding an (obvious?) deeper truth.

I think that to appreciate Hanson's method of argument you must adopt a view of science as a collection of imperfect models and humans as irrational monkeys playing with the models and often overlooking valuable inferences and insights.

Put another way, under what circumstances would one of Hanson's proposed prediction markets fail to achieve equilibrium (liquidity)? Your analysis would suggest that you would bet $0.99p or $0.01p on any of the contracts and happily await reality to prove Hanson foolish. That's the point of such markets, however. Hanson would love to be shown that one of the markets he suggests had that quality, as the price would be valuable information about the robustness of the underlying constructs.

> One thing that troubles me about rationalist-affiliated writing is that it tends to rest on what looks, at first glance, like a decent evidence base, but this evidence often breaks down under a little scrutiny.

This is very true, and the rationality community has plenty of its own sacred cows (prediction markets are a great example) which this type of “evidenceyness” is used to confirm all the time.

Every community is bound to have blind spots and biases. Perhaps there is nothing more important than critical thinking to avoid building a community around.

> Here the key question here is: what sort of things should you expect to have already seen, if they were really there? On the one hand, we clearly have seen enough to safely conclude that there aren’t large dinosaurs roaming the streets in our major city centers. On the other hand, we often hear reports of people uncovering old things that others had confidently predicted would never be found. Which makes many suspect widespread overconfidence in claims about what we know can’t be there, because if so we would have seen them already.

This wording is very reminiscent of a lot of writing from conspiracy theorists. It starts with a very plausible claim that experts are sometimes overconfident in a mainstream belief about topic X, but then immediately leaps to the conclusion that we can therefore make up any claim whatsoever about topic X and it ought to be treated just as seriously as mainstream beliefs held by experts.

You see this all the time in government/political conspiracy theories. Yes, we have in the past uncovered real substantial government conspiracies and attempted cover-ups. But that doesn't mean that any claim whatsoever about a government conspiracy is true or should be treated "with the same priors" as any other claim. Likewise, the fact that some experts have been wrong about what artifacts they expected to find in a certain archaeological dig does not mean that all claims about human history should be treated with the same level of seriousness. The fact that sometimes evidence is hidden (either deliberately, or due to lack of resources, or due to misguided research, etc.) does not support any arbitrary claim made without evidence of its own.

> This wording is very reminiscent of a lot of writing from conspiracy theorists

I think this dismisses the article as a whole a bit too quickly.

> The fact that sometimes evidence is hidden... does not support any arbitrary claim made without evidence of its own.

Agreed. I didn't interpret the author as trying to imply this. I think the author was trying more to fight an instantaneous "no you're definitely wrong" than to convince the reader "yes this author's claim is correct."

I think it doesn’t. A lot of conspiracy theorists use a technique where they start with something that is true, some facts A and B, and then C is controversial. You let your guard down with A and B, and are more susceptible with C.

He is honest with the extraordinary proof he needs, but his article never much strays from pure speculation. It’s a nice flight of fancy.

A lot is lost to history, no doubt, which skews our understanding greatly, especially prehistorical. But that is Dozens of steps away from finding a laptop from 10000bc or marsial burial chambers and having your advanced civilization theory stick.

The article felt like shoehorning theories / finds to make them stick in his view.

...but I think the author is being honest about it being speculation. If you read the article to the end, his conclusion is that outlandish speculative claims should be incentivized to be proven through a betting market that can reward proof proportionately.

ie. Having the mainstream put their money where their mouth is.

I don't see an issue with that. He isn't actually claiming that prior civilizations exist - simply that it's plausible that they did (depending upon what you interpret as "advanced").

> Some supporting evidence comes in the form of writings from the earliest authors we can find, who explicitly claim that they descended from more advanced prior civilizations, who fell due to big cataclysms. This story is actually quite common.

It's hard to know to what extent Golden Age and Age of Heroes myths were rooted in or developed out of real events, but by the time many of these myths were written down civilization really had collapsed across the Near East and Mediterranean some 800 years earlier [1]. The Late Bronze Age collapse was in many ways more catastrophic than the fall of the Roman Empire 1500 years later.

But the civilizations that fell during this time period were civilizations from which we have ample evidence like the Mycenaeans (who may have been the inspiration for Greek Golden Age myths), not some mysterious civilization that had invented Segway scooters tens of thousands of years in the past.

[1]: https://en.wikipedia.org/wiki/Late_Bronze_Age_collapse

This fits Occams Razor much better than what the article proposes.

I still wonder what inspired Plato's Atlantis.

Do you also wonder what inspired J K Rowling's Harry Potter? Or Ayn Rand's Atlas Shrugged?

We are quite capable of pure fiction with symbolic inspirations, there is no need to suspect "a kernel of truth" behind any speculation.

Many classical mythologies had basis in reality: the Iliad is a great example. Why are we so sure Atlantis is a myth (or allegory) while the stories of the Bible are based on real events? It’s just not that simple.

That's very simple: because Atlantis was presented as an allegory by its inventor, while most of the Bible was intended as history. Wondering where the real Atlantis was makes about as much sense as asking who was the historical prodigal son...

We know Europe is a real place and that actual countries called France and the UK existed at the time HP is set in.

Crete, which was destroyed by a volcanic eruption:

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

Or Santorini https://en.wikipedia.org/wiki/Santorini#Speculation_on_an_At...

Yeah, both were part of the Minoan civilization, which suffered significant decline after the eruption.

I don't know about lost civilizations, but ancient Rome was using concrete technology unknown to medieval builders[1]. Somewhere along the line, this super concrete recipe was lost. I find this really fascinating and some believe that ancient Egypt also created its pyramids using man-made stone instead of quarried stone:

> His most remarkable claim is that the pyramids were built using re-agglomerated stone, a sort of geopolymer limestone concrete, rather than blocks of natural stone.

[1] - https://www.wired.com/2009/10/super-concrete-in-the-us-milit...

The recipe for Roman concrete was recorded, but most places didn't have access to the materials and conditions necessary to produce it: https://www.sciencemag.org/news/2017/07/why-modern-mortar-cr...

I'll have to dig out an archaeologist but I don't thank that is quite right. I'm a Civ Eng graduate BTW.

Romans - conc - yes. Inventors - maybe but probably not (see below) Medieval period - conc - probably available and probably used

Conc is a funny old beast. Basically, it is a chemical reaction between its ingredients and not a drying out and setting thing. That's why it will set underwater or if you pour too much in one go, it will set itself on fire - exothermic reaction.

I suspect with no evidence whatsoever that someone will have noticed how mixing water with some types of earthly deposits etc etc.

Look at "cob" which is straw and mud and water and some pretty interesting admixtures - starting with wee (horse and human.) My aunt and uncle's last place had 1620 written on the wall near the entrance - so a bit modern for these parts. It is cob and thatch with a few sticks thrown in.

I suspect that conc of some sort is ubiquitous throughout history and has simply not been noticed by us modern lot. However it does generally require processing of some of the raw ingredients so perhaps I'm off course.

My understanding is that Roman concrete recipe/technique is considered uneconomical for most uses today because it uses very little water and must be mixed onsite and packed into place, which makes it much stronger even without rebar. But that doesn't work so well for mixing in a truck and driving to job-site, so modern industry prefers a much wetter mix even though it means our structures crumble in decades rather than millenia.

Where the similar recipe/technique has been applied is in the construction of some large dams, where they call it roller compacted concrete.

see romanconcrete.com

did anyone made tensile tests on a roman concrete specimen? Rebar is wildly used because reinforced concrete is not only used in compression but in beams, slabs ... and could be avoided in arched structures. Arches and domes can last a lost longuer but limit choices in what can be built. Roman concrete should be compared to modern concrete without rebar or this is comparing apples to oranges.

It's just a different tradeoff. We could absolutely make "Roman" concrete that lasts millennia, but it has a much lower strength than modern concrete so you can't make something like a harbor quay out of it. That said, "lasting a thousand years" is not as useful as it sounds, 99+++% of buildings will need to be demolished before that time anyway.

> you can't make something like a harbor quay out of it

Are you sure about that? The Romans built a lot of harbours. We don't really have any data on the compressive or tensile strength of Roman concrete so it's hard to say for sure.

You can't make a _modern_ harbor quay out of it, one that is strong enough for the super large container cranes. The main problem is of survivorship bias: all the flimsy Roman harbors have disappeared so yes, only the most sturdily constructed ones remain. They would still not last under the "modern" load of 40+ ton vehicles.

>You see Mars is, a priori, just as likely a place for life to start as Earth.

Asserted without evidence, and considerable waving of hands detected.

We have no good evidence or accepted model for how life started, besides "randomness" in a primordial soup, which is as good as "no idea". As such, it seems like a reasonable assumption to explore.

That's untrue. See here https://www.scientificamerican.com/article/how-did-life-begi....

An "Earthlike" planet is required. Mars may have qualified at one point, but doesn't now.

An earthlike planet is require for earthlike life.

It is fallacious to assume other life couldn't be different -- we can't prove or disprove that. Likewise, we still don't know exactly how life started here; we simply have a few good theories.

this is what has always annoyed me about basically every space movie ever made. even life a star away, let alone another galaxy away, is likely to be startlingly different from the oxygen-absorbing, ossified calcium-braced, protein-enriched, atp-powered water blobs with heads, legs, and feet we have on earth. and that's just the the biochemical stuff we're familiar with.

What bothers me about every space movie made is that all those planets have life on them (or, worse, intelligent life). Fermi says hi.

Fermi can blast out "Hi" with a 100GW of power and he is unlikely to be heard in Andromeda, which for all we know could be teeming with life and host to something like an Iain Banks Culture series space opera.

We know that fewer than about 1 in 100,000 galaxies has a Kardashev Type III civilization. So the Fermi argument has some bite even at cosmological distances.

But anyway, this was about SF movies where our heroes visit Arglebarg IV and have adventures with the natives. It's like Victorian adventure stories transplanted into space without bothering to think things through. Let's kill our dysfunctional tropes.

> We know that fewer than about 1 in 100,000 galaxies has a Kardashev Type III civilization.

But we.. don't? We just don't have anything to compare to.

A K3 civilization is one that has diverted a significant fraction of the stellar output of a galaxy to its own uses. They have to dump their waste heat somehow, and that's visible in the far to mid infrared. So we can compare the IR emission of galaxies to look for oddballs with a lot of IR.

https://www.centauri-dreams.org/2015/04/16/g-hat-searching-f...

“Our results mean that, out of the 100,000 galaxies that WISE could see in sufficient detail, none of them is widely populated by an alien civilization using most of the starlight in its galaxy for its own purposes. That’s interesting because these galaxies are billions of years old, which should have been plenty of time for them to have been filled with alien civilizations, if they exist. Either they don’t exist, or they don’t yet use enough energy for us to recognize them.”

When we assume K3 capabilities, why don't we assume they dump their waste emissions away into something like (artificial even?) black holes? Maybe they are shy and afraid of the intergalactic "Dark Forest"? ( https://en.wikipedia.org/wiki/The_Dark_Forest )

The basic problem with that idea is black holes are too small. The amount of low temperature radiation that one could dump into them would be insufficient.

I think the point is that if a large number of galaxies had Type III civilizations, we would notice, because the definition is that they use most of the available energy in their galaxy making the galaxy radiate more infrared than visible light. But that doesn’t mean life isn’t common, it may just mean that a Type III civilization is either physically impossible or very unlikely.

i think in the end it's going to come down to what you really consider "life" to be.

there is an implicit part of our definition that includes timescales and size, and this puts some limits on the type of chemistry that can be involved in order to qualify.

if you open up the definition to be things that work on totally different timescales and sizes than we consider, then i think its fair to say that the chemistry doesn't need to be similar at all.

but for things that form blobs of life on the rough range of scales found on earth, and that "do stuff" in the range of timescales that we see on earth, there are not too many choices. silicon often gets touted as an alternative because of its ability to form branched structures. do you know of any other ideas?

sure, chemistry has a somewhat limited palette to work with, but life happens in the gap between potential and kinetic, between hot and cold, between proton and electron. that's a tiny space but a huge gap.

dna is mostly a 4-note tune, and computers, the potential precursor to artificial life, 2. i'm sure something as vast as the universe can come up with a little more variation than skin type in those tiny little gaps.

I don't believe that we'd recognize computer-ish artificial life as life in the sense that we're discussing here.

ps. I have my Artificial Life III conference t-shirt from 1994 :)

Due to convergent evolution [1], I'm not sure life that originated on an Earth-like planet would look completely different from Earth life, at least on a macroscopic level.

[1]: https://en.wikipedia.org/wiki/Convergent_evolution

that's predicated on the same conditions as life on earth. a universe can surely come up with some more variety.

My point is that I think convergent evolution would be likely to produce “water blobs with heads, legs, and feet” on other Earth-like planets, i.e. planets with lots of liquid water and lots of solid land.

If you’re thinking of planets that are not similar to Earth, of course all bets are off.

> atp-powered

I think GTP-powered file is possible, even the glucose metabolism produce one GTP (and many ATP). (Perhaps I'm missing something, Chemistry is not my main specialty). Perhaps it is even possible to have NADH-powered life, but it is more different so it may be impossible.

> ossified calcium-braced

Diatoms use silica, insects have a protein exoskeleton, and octopus are weird.

> oxygen-absorbing, [...] protein-enriched, [...] water blobs

I guess these three are safe bets (with a little different selection of amino acids).

Oxygen absorbing isn't necessary, of course. Life on earth got along without it for a while until those darned cyanobacteria starting poisoning everyone else.

Eukaryote life did not appear until after the Oxygen Catastrophe though.

That's true, but how much earlier might it have occurred if the oxygen catastrophe had not occurred and caused a mass extinction? Hard to say...

I don't think we have "good" theories about how life started here. In particular, the complexity gap from abiotic chemicals to the smallest known organism capable of independent reproduction (about 4 billion atoms!) is extremely large, and no theory has done more than handwave about how that gap is to be crossed.

That's also discussed in the article. The author states that Mars may have qualified before Earth did.

Edit: Also, the article you linked specifically states "Scientists debate a range of ideas about how life on earth began", undermining your first point.

>Martian surface temperatures vary from lows of about −143 °C (−225 °F) at the winter polar caps[14] to highs of up to 35 °C (95 °F) in equatorial summer.

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

Had to look this up. Seems like there is the same temperature window available on Mars that is needed for life on earth.

That’s today without atmosphere, liquid water and with a solidified core I’m not sure were close to estimating when the core has solidified as far as I know we also have no method for dating anything on mars.

When mars was wet, geologically a GI d and still had an atmosphere the temperatures would’ve been much closer to earth today.

The Mars panspermia theory mentioned in the original article simply moves the "randomness" to a primordial soup 83 million km away during the same time frame, and adds the exceptionally strong claim that Mars was so much more conducive to spontaneous formation of organisms capable of surviving on earth that it is more probable life emerged there and made an unexplained interplanetary journey than it emerged on the planet it currently [exclusively] lives on.

Considering the best evidence of Mars being conducive to earthly life formation is the likelihood of it more closely resembling earth's conditions in the past, it doesn't seem like the sort of claim likely to resolve issues with earthly primordial soup hypotheses...

I think the opposite conclusion is true: we know nothing about how life gets started, we know life exists on Earth, we have seen no evidence of life anywhere else, so the reasonable assumption is that life started on Earth.

One thing we know (almost) for sure is that no new forms of life have emerged on Earth for hundreds of millions of years. So we should expect that the conditions required are quite special indeed, or the event is extraordinarily unlikely. As such, it is silly to assume that any other planet is "similar to Earth" in the ways that matter for life appearing based on simplistic observations (temperature, distance from the sun, existence of the most basic required elements).

Do plants count? Then I have cacti for you, which are thought to be only a few dozen million years old.

I am referring to abiogenesis - life arising from non-life matter. Cacti have not appeared out of simple chemicals, they have evolved from other plant-based lifeforms (in fact, there is no "first cactus").

My point is that, despite the huge abundance of life on Earth today, it is all based on a very old abiogenesis event, with all indications that it was more or less a singular event.

All life on earth seems to be part of the same philogenetic tree, so it seems that life appeared once and then kept evolving from that initial life-form. Of course, there is a good chance that there was some variety of initial organisms that either merged together in symbiotic relationships, such as mitochondria with the rest of the cell, or got out-competed by the one type of organism that we are all descended from. This still indicates that life arose in a single place and only over a relatively short amount of time.

Hm. OK. thx.

"a priori" means "from theoretical deduction rather than evidence or experience", so yes, that's entirely the point of that sentence.

What the author is saying is "theoretically, life could have started on Mars just as easily as it did here".

The theories we have about how life started on Earth tend to disfavor Mars as a similar starting point, based on what we currently know about Mars.

I think the author was trying to say "I mean, look, Earth and Mars are not that different, and even though we don't have any current evidence for the appropriate chemical conditions on Mars, I don't see why it couldn't have been where life started instead of Earth, because ... well, just because they're sort of similar, kind of. Oh, and next to each other."

Those theories don't have much in the way of evidence that would compel anyone to believe them, though. So citing them isn't much of an argument.

based on what we currently know

In two hundred years, conclusions drawn from what we currently know will be as out of date as conclusions from two hundred years ago are today. Or to put it another way, things known to the best of our knowledge are both as good as we can do and probably wrong because one of the things we know is that historically most of what people know at any given time turns out to be wrong at any given time.

Absolutely correct. But this article was written now, and makes a claim that is totally unsupported by anything we know now.

I'm entirely down for our descendants in 200 years laughing at our scientific parochiality, just like we often get to do at our double-century antecedents. But that doesn't justify writing right now that Mars and Earth have a priori likelihoods of being the origin of life in the solar system.

Citation needed.

There's plenty of evidence Mars once had much more surface water than it does today. IIRC liquid water is one of the primary preconditions for the evolution of Earth-like life.

What about Mars disfavoured it?

"theoretically, life could have started on Mars just as easily as it did here"

Yes, leaving aside the 20% lower luminosity of the sun[1] a few billion years ago (when Mars had a reasonable atmosphere) putting Mars outside the habitable zone, and Mars's lack of plate tectonics and a protective magnetic field: -

Life certainly could have evolved on Mars. I expect that one day prion-like or viroid-ish molecules may well be found. But so what?

It's one or two billion years from there to a bacterium, let alone a lost civilisation. And Mars did not have the time.

[1] https://en.wikipedia.org/wiki/Faint_young_Sun_paradox

Your linked article actually says there is evidence Mars was warmer and wetter in the past. How then was it "outside the habitable zone"? And what proof do you have that life 4B years ago needed to be in what we define now as a habitable zone, needed a magnetic field, and needed active plate tectonics to arise? These are exactly the kinds of assumptions the article is challenging.

Life didn't need those things to arise; that's just a matter of the right chemistry and physics being available for a relatively short period of time.

But it would seem to need them for sustained evolution to be possible. So as I said, I'd expect lifeforms at the complexity level of viroids, but not at the level of eukaryotes.

Evolution needs time, lots of time in which conditions don't change too much. (Chemistry that works in dilute solution at 300K doesn't work well at 200K or 500K.) It also needs populations to be able to spread to new areas.

Without a magnetic field, Mars's atmosphere got stripped off. No more liquid water, no more areographical distribution, so no more evolution.

Plate tectonics is needed to ensure that nutrient chemicals don't get locked up permanently in sedimentary rock.

As for the habitable zone, life as we know it needs liquid water on the surface. Mars may have briefly been habitable, but not for long enough.

To be a challenge, the article needs to provide plausible alternative evolutionary pathways that get us eukaryotes without needing these things (time, liquid water, chemical recirculation, limited variability in physcal conditions). It doesn't do that. It's just spitballing.

If early Mars was OK for life to begin, then so was early Earth. We don't need any interplanetary travel.

Thanks for the detailed explanation, great points. I really wonder how the volume of liquid water on Mars has changed over the aeons. Considering there is still liquid water today, I would still be cautious about claiming "no more evolution on Mars".

https://www.nasa.gov/press-release/nasa-confirms-evidence-th...

What point is there in making a theoretical deduction about an empirical issue?

Yes, life could have 'theoretically' started anywhere where life by definition is possible. Fine, but that's a tautology, and in contrast to what the author seems to believe actually not scientific and thus deserves to be rejected.

If we're talking about scientific statements then show me life actually existing somewhere that isn't earth and then we can make some grounded theories

I suppose if your theory was that god created life that would definitely make Mars just as likely a starting place, or if the theory is that life actually came from some meteorite impact, but most theories for life's origins do not seem to favor Mars.

I mean when you say theoretically and then make a big not necessarily obvious statement you should actually point out which theory you're using.

Prizes for finding specific things in specific years don't reflect the structure of how ancient archaeology actually works. Picking domesticated horses as a hopefully representative example:

* The earliest clear, irrefutable example of domesticated horses - horses and chariots put into a grave together - is from 2000 BCE.

* Most sources are confident horses were domesticated by 3000 BCE.

* There's archaeological evidence for domestication as early as 3500 or 4000 BCE.

* The closest known wild relative of the domestic horse diverged genetically tens of thousands of years ago. But it's believed that this was a natural event, and Equus ferus caballus was wild for some time before humans domesticated it and drove the wild stock extinct.

If there's a prize for showing horses were domesticated west of the Caspian see before 3000 BCE, is it awarded or not? I don't know and I don't see any great way to decide.

Off topic, but on the topic of your specific example: there's a nice book called The Horse, The Wheel, and Language[1] about this.

Great if you want to learn about analysing fossil horse teeth for bridle bit wear. Oh, and about Indo-European languages.

Edit: By 'you" I didn't mean parent specifically but "the reader".

[1] https://en.wikipedia.org/wiki/The_Horse,_the_Wheel,_and_Lang...

Sigh...

another piece for my Tsundoku-stack.

;-)

https://arxiv.org/abs/1804.03748

If an industrial civilization had existed on Earth many millions of years prior to our own era, what traces would it have left and would they be detectable today? We summarize the likely geological fingerprint of the Anthropocene, and demonstrate that while clear, it will not differ greatly in many respects from other known events in the geological record. We then propose tests that could plausibly distinguish an industrial cause from an otherwise naturally occurring climate event.

If such a civilization was confined to the shores of what is now the black sea, but which before the current interglacial was a fresh water lake whose level was much lower than today's, then no, we wouldn't be able to detect it casually -- we'd have to work real hard to find it. For civilizations confined to open sea shores the situation is much less dramatic because the sea level rise there was less than at the black sea, but still, there could be some that are 30 meters under water (accessible) but completely covered in sediment (so inaccessible).

Seems... unlikely to me. Plausible, yes, but unlikely. In particular any pre-interglacial civilization would have had to develop during the preceding glacial period, not before it because that would take it back 100Ky, which is too much to be believable given what we know so far about our species' evolution (though anything from more than 100Kya would be hard to find indeed). And evidence of it would have to have been destroyed by sea level rise during the interglacial, but why would the civilization itself be destroyed by the interglacial?

I think you’re correct. The story on our species is known to degree that it’s unreasonable that an advanced agricultural civilization existed. I think it’s more likely that far further back, a dinosaur species achieved a more advanced state than we think possible today. Not quite agricultural due to a lack of tool use, but as far as you can go without the opposable thumb. Advanced social structures and nomadic. It’s pointless speculation, but I do think it’s more likely given the timespan available.

If there had ever, in the last few million years, been mining on a scale comparable to what goes on today, we'd notice. Some natural resources would be used up. The oldest mountain range on earth is over 3 billion years old. It's in South Africa. It's being mined. It's not mined out.

If this planet ever had an industrial civilization, every once in a while we'd find something made of gold or stainless steel or ceramic. Not happening.

One of his arguments is that continents and sea levels changed and you don't need to go back incredibly far to see this. Maybe the mines are all under the sea. How much of the sea bed have we explored?

It sort of depends on what you mean by "advanced". A civilization that simply had pottery 50K years ago, would be considered "advanced" and a major major breakthrough.

If it did only happen on an island which is today submerged, then probably we will never discover it without major investments to look (which are poor investments since the probability is low).

...and hence, the author's main insight is that low-probability discoveries should be incentivized by prediction markets such that those who believe in the status quo can safely buy their positions - and that anyone who can upend the status quo is richly rewarded.

I think that, conceptually, has merit.

I fear the market Hanson proposes would incentivize skilled hoaxes as much or more than authentic discoveries.

It definitely sets up perverse incentives. Archeological dating is difficult and easy to screw up. Incorrect yet "plausibly deniable" mistakes can get you dates far off from reliably established estimates. There's also a problem of what the end criterion is. Is just publishing a paper in a reputable journal enough? Does it need secondary confirmation, or the decade+ of debate that boundary-pushing finds like Monte Verde require to be established?

This. (and you could probably reply to 90% of Hanson's 'you can solve problem X with a prediction market' posts with essentially the same argument)

It's not like people with understanding of archaeology aren't already highly incentivised - financially and otherwise - to discover evidence of ancient civilizations if it's actually there. Archaeological frauds exist even now, and even where there is no fraud there are enough disputes in dating and what actually constitutes advanced civilization to guarantee a prediction market in archaeological discovery is going to have a massive oracle problem...

You could make that argument about any incentive system. That does not negate the utility of incentives - it simply requires that they are structured correctly to vet evidence.

That's just the natural consequence of a free market. If it is cheaper and easier to hoax, people will do it. It also incentivizes cheaper recovery of archeological artifacts, saving money in the exfiltration process. Not good.

Imagine they were so advanced that they had the ability to 3D-print really everything in high volumes from the quantum level up. From large scale building materials analog to our concrete and steel to metamaterials, isomers, Nano/Synbio, whatever.

What to do about the rat-race/treadmill?

Of course artificial scarcity by ubiquitous DRM embedded at quantum-level in absolutely everything!

Which after a while of missed payments self-destroys into ecologically safe mono-fractions.

Ashes to ashes, dust to dust, gone with the wind...

edit: or instead of missed payment a simple countdown/timeout, because why have old things at all?

Why even bother with quantum DRM? A sufficiently advanced organization of matter is indistinguishable from noise if you lack the capability to decode it. See an encrypted file or a butterfly chrysalis: it all looks like noise to us, but something emerges with the right key.

What if there was no hierarchy in this proposed civilization? Or what if they developed the means to encode civilization-wide access rights to every object they handled by saying “the nth crystalline molecule from the top (read right-to-left) has your signature flaw embedded in it?”

We have no way of detecting that with our current tech level, and even if we could trivially detect the crystalline flaws it doesn’t mean we’d see or comprehend the scheme they employed. Working with a tech model that we understand (well, some of us, not including me), if you handed a hard drive to a Roman emperor and told them what it held, they wouldn’t be able to do anything with it or even examine it non-destructively even if they put the whole of the empire to the task.

Ain’t trying to say that it existed. I do like the remark in one of the Culture series that says technology is more like a rock face than a line: different sequences of discoveries lie along the path that a particular civilization travels. There’s lots of room for surprise, whether discussing ancient, contemporary, or future civilizations.

There was an old joke about people trying to compare their ancestors' prowess:

At the EU council, the Italian representatives come one day and say: we have definitive proof that Romans were the most advanced civilization that ever lived! We have dug 20 meters under the current soil level and found copper, obvious proof that they had mastered DSL internet!

Next year, the same forum, a Frenchman comes up and declares: we have discovered evidence showing conclusively that the Galls had the most advanced early culture! We dug for 30 meters and found glass, so they had already mastered fiber glass-based internet!

One more year afterwards, the Romanian representative comes out and explains: previous claims by my colleagues have been investigated and found false. It was in fact the Dacians that the most advanced internet of the ancient world: we have dug for 20 meters, 30 meters, even 40 meters, and everywhere found nothing at all - uncontroversial proof that they had already mastered wireless communication!

Here are some problems with prediction markets that Tyler Cowen enumerated in 2006: https://marginalrevolution.com/marginalrevolution/2006/03/wh...

That was before machine learning became a thing. I wonder if ML can detect patterns in voting behavior to downrank/uprank certain predictions to get closer to the likely truth. Obviously the more liquid the market is the better.

Edit: Someone downvoted me but I'm not sure they're aware that Robin Hanson (the author) is a big advocate of prediction markets, which are also a central feature of the original post. I think highlighting the issues with prediction markets and speculating about a solution is germane to this discussion, especially since prediction markets can be very valuable for society.

Those look very specific to using employee-only prediction markets to guide decision-making within a single company. Which objections, if any, do you think apply to Hanson's proposal for tradable archaeology prize obligations?

Abstracting away from the corporation-specific concerns, there is an incentive problem. Vested interests can seek to lower the usefulness of the market's "price as a signal" by placing large diversionary bets. Granted, this is relatively less likely to be a problem in the archaeology space. What definitely may be an issue is lower liquidity.

Every time I see a post like this I think "where are all the prediction markets?" Regulations are one reason, but that's far from the only reason. If information/prediction markets are enhanced using new technology, regulators will begin to respect them more and allow for widespread use in non-academic contexts.

If there are remains of a civilization from, say, 15000 years ago, very few are looking for it. In the Americas it is very hard to get permission even to continue digging below the Clovis layer.

Furthermore, it is just as likely to be under 60+ ft of water. We don't need to find the water for a worldwide flood -- it's all still there, since the ice melted, right there in the sea. Literally tens (or hundreds, going back a little farther) of thousands of square miles of what was very recently dry land is now underwater, more than enough room for some regional empires.

People who lived on those square miles had to pick up and move uphill, and leave their ancestral homes behind. (That, as anyway, is pure fact.) Australians have oral history of the conflicts that move caused, because other people already lived uphill.

It's not an extraordinary claim. Nothing makes it prima facie unlikely. It just takes looking for evidence in places no one has chosen to look, yet.

We do know that a sophisticated civilization (tree-)farmed the whole Amazon basin, right up until they were wiped out by smallpox 500 years ago. LIDAR reveals many, many miles of huge earthworks. No one suspected, only a few years ago. We still know hardly anything about them. So, no, lost civilizations are not an extraordinary claim.

Lack of lost civilizations, where they ought to have arisen, needs explanation.

> So, no, lost civilizations are not an extraordinary claim.

> Lack of lost civilizations, where they ought to have arisen, needs explanation.

Well, lost cultures as advanced as, say, the builders of the Egyptian pyramids, but significantly older, is still an extraordinary claim.

In fact, claims of any kind of civilization existing require some kind of proof - it makes no sense to say "the British isles can sustain a thriving civilization today, so we should assume that there was a civilization present there 100k years ago, unless we have some evidence to the contrary (or at least wonder why no civilization flourished there some at that time)".

No, it is an ordinary claim, requiring ordinary evidence.

The Egyptians had no magic powers. They had population, surplus food, and regular human ingenuity. Anywhere that happens, civilization arises, like desert wildflowers after a rain. If the wildflowers don't bloom, that requires explanation.

You do understand that we need evidence for everything, right?

But bending over backward to try to discount the evidence we have because it must be not just regular, workaday evidence, but extraordinary evidence, is not science. It is, instead, hardscrabble turf defense, and nothing to brag about.

So, assume this is all true. We came from Mars and advanced civilizations came and went, completely undetected. Who the fuck cares? Isn't not like we can dig up their ancient technology and use it now, can we? It's a fantasy for people who don't have the imagination to believe in dieties. Super-advanced-yet-dead civilizations are a cheap imitation of dead Gods.

The scifi novel "The Hab Theory" by Eckert goes into some interesting debate about whether there were unknown previous advanced civilizations or not. It sounds almost plausible, but not quite.

"Inherit the Stars" by Hogan is another interesting take on it.

There is a fringe theory similar to HAB (thx for mentioning it btw., didn't know that) wherein the earth tilts by about 90 degrees for a few days and then back, but the mechanism is different. Supposedly caused by changing magnetism and structure/viscosity of some larger parts of earths molten layers, changing the center of gravity for a while, and so on.

Clearly the author has not eaten boxes of those newly legalized brownies and binge watched seasons 1 through 15 of "Ancient Aliens." If he had, he would know that "ancient astronaut theorists, would say yes."

It's entertaining, but what subtle improvement has he made on the work of eminent theorist Giorgio A. Tsoukalos?

No binge watching of bad hair required. 20 minutes suffice. (even less, because skippable/fast-forwardable)

The Unusual Earth Orbit Circling Above Our Ancient Past | Roger G. Gilbertson | TEDxColoradoSprings

[1] https://www.youtube.com/watch?v=_HytJn6uaRk

Maybe another (less than if fast forwarded) 30 minutes for

Proof a Mysterious Lost Ancient GLOBAL Civilization Spanned Virtually the Entire Planet… from:

[2] https://www.youtube.com/watch?v=BTd1fRCAvR4

A reminder of the rather more ancient civilisations imagined in the Silurian Hypothesis thought experiment of a couple of years ago:

https://www.wikipedia.org/wiki/Silurian_hypothesis

Prediction markets are not legal in the U.S.

(There are some with low limits, like $1000 per position or $5k per person---I don't remember exactly---but I do not consider those to be "real" prediction markets.)

RE not found evidence: I always imagine what would have happened if we were to start with biology based tech. A few centruries, and poof, nothing left. Now, put that into a million years perspective...

That depends on what you mean by biology-based tech, afterall, we're also a civilization deeply rooted in biology-based tech.

It's not necessarily the case that all organic materials are ephemeral over these timespans. Assuming that a tool-using civilization would have needs covering a wide range of material properties, including high corrosion resistance, there is no reason why even biologically-grown building materials would automatically be less durable than, say, concrete. Not to mention the tools and trinkets of everyday life. The assumption is that a large population always has a large footprint regarding the traces it leaves behind, even if that footprint is very different from ours. We found this to be true in fossils that have been left behind even by exceptionally fragile creatures.

Once we're talking advanced biology-based tech, this becomes even more pronounced. Outright genetic engineering in Earth's past would be bound to leave very curious traces in lifeforms that are around today. In fact, if I wanted to leave a message behind for a hypothetical civilization located on this planet a million years into the future, leaving it in DNA would be one of the very few viable choices.

I would posit that even DRMed biotech designed to turn every single piece of a civilization into mud once the license runs out would leave behind very detectable traces in the form of strange geological deposits and individual artifacts that survived against all odds.

Given that we have fossil records of life that lived much more than a few million years ago, I don't think biological tech would be expected not to leave any traces.

The last paragraph is an example.of innovation that can only be achieved with blockchain projects like Augur prediction markets and ettlements. Cool stuff

Archaeologists have discovered a 7,000-year-old well built by Neolithic farmers in what is now the Czech Republic.

https://www.cbsnews.com/news/ancient-well-oldest-wooden-stru...

7000 years is pretty modern, it’s almost 3k years after agriculture started being adopted in multiple regions. There are older artifacts than that, intelligent humans have been on the planet for a long time.

I was perturbed by the offhand way he linked to a climate-change denialist website (as part of his assertion that "before 10k temperatures changed a lot more").

I don't think you get to call yourself a rationalist if you ignore the overwhelming scientific consensus in favor of a blog run by right-wingers.

How does this kind of garbage reach the top of HN?

It seems that dilettante intellectuals have rebranded themselves as "rationalists". Why is it that their blog posts are always high school book report level quality.

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