Fermi paradox of human past, and corresponding x-risks

post by turchin · 2016-10-01T17:01:48.832Z · score: 6 (7 votes) · LW · GW · Legacy · 28 comments


  3. Civilisations are rare

Based on known archaeological data, we are the first technological and symbol-using civilisation on Earth (but not the first tool-using species). 
This leads to an analogy that fits Fermi’s paradox: Why are we the first civilisation on Earth? For example, flight was invented by evolution independently several times. 
We could imagine that on our planet, many civilisations appeared and also became extinct, and based on mediocre principles, we should be somewhere in the middle. For example, if 10 civilisations appeared, we have only a 10 per cent chance of being the first one.

The fact that we are the first such civilisation has strong predictive power about our expected future: it lowers the probability that there will be any other civilisations on Earth, including non-humans or even a restarting of human civilisation from scratch. It is because, if there will be many civiizations, we should not find ourselves to be the first one (It is some form of Doomsday argument, the same logic is used in Bostrom's article “Adam and Eve”).

If we are the only civilisation to exist in the history of the Earth, then we will probably become extinct not in mild way, but rather in a way which will prevent any other civilisation from appearing. There is higher probability of future (man-made) catastrophes which will not only end human civilisation, but also prevent any existence of any other civilisations on Earth.

Such catastrophes would kill most multicellular life. Nuclear war or pandemic is not that type of a catastrophe. The catastrophe must be really huge: such as irreversible global warming, grey goo or black hole in a collider.

Now, I will list possible explanations of the Fermi paradox of human past and corresponding x-risks implications:


1. We are the first civilisation on Earth, because we will prevent the existence of any future civilisations.

If our existence prevents other civilisations from appearing in the future, how could we do it? We will either become extinct in a very catastrophic way, killing all earthly life, or become a super-civilisation, which will prevent other species from becoming sapient. So, if we are really the first, then it means that "mild extinctions" are not typical for human style civilisations. Thus, pandemics, nuclear wars, devolutions and everything reversible are ruled out as main possible methods of human extinction.

If we become a super-civilisation, we will not be interested in preserving biosphera, as it will be able to create new sapient species. Or, it may be that we care about biosphere so strongly, that we will hide very well from new appearing sapient species. It will be like a cosmic zoo. It means that past civilisations on Earth may have existed, but decided to hide all traces of their existence from us, as it would help us to develop independently. So, the fact that we are the first raises the probability of a very large scale catastrophe in the future, like UFAI, or dangerous physical experiments, and reduces chances of mild x-risks such as pandemics or nuclear war. Another explanation is that any first civilisation exhausts all resources which are needed for a technological civilisation restart, such as oil, ores etc. But, in several million years most such resources will be filled again or replaced by new by tectonic movement.


2. We are not the first civilisation.

2.1. We didn't find any traces of a previous technological civilisation, yet based on what we know, there are very strong limitations for their existence. For example, every civilisation makes genetic marks, because it moves animals from one continent to another, just as humans brought dingos to Australia. It also must exhaust several important ores, create artefacts, and create new isotopes. We could be sure that we are the first tech civilisation on Earth in last 10 million years.

But, could we be sure for the past 100 million years? Maybe it was a very long time ago, like 60 million years ago (and killed dinosaurs). Carl Sagan argued that it could not have happened, because we should find traces mostly as exhausted oil reserves. The main counter argument here is that cephalisation, that is the evolutionary development of the brains, was not advanced enough 60 millions ago, to support general intelligence. Dinosaurian brains were very small. But, bird’s brains are more mass effective than mammalians. All these arguments in detail are presented in this excellent article by Brian Trent “Was there ever a dinosaurian civilisation”? 

The main x-risks here are that we will find dangerous artefacts from previous civilisation, such as weapons, nanobots, viruses, or AIs. And, if previous civilisations went extinct, it increases the chances that it is typical for civilisations to become extinct. It also means that there was some reason why an extinction occurred, and this killing force may be still active, and we could excavate it. If they existed recently, they were probably hominids, and if they were killed by a virus, it may also affect humans.

2.2. We killed them. Maya civilisation created writing independently, but Spaniards destroy their civilisation. The same is true for Neanderthals and Homo Florentines.

2.3. Myths about gods may be signs of such previous civilisation. Highly improbable.

2.4. They are still here, but they try not to intervene in human history. So, it is similar to Fermi’s Zoo solution.

2.5. They were a non-tech civilisation, and that is why we can’t find their remnants.

2.6 They may be still here, like dolphins and ants, but their intelligence is non-human and they don’t create tech.

2.7 Some groups of humans created advanced tech long before now, but prefer to hide it. Highly improbable as most tech requires large manufacturing and market.

2.8 Previous humanoid civilisation was killed by virus or prion, and our archaeological research could bring it back to life. One hypothesis of Neanderthal extinction is prionic infection because of cannibalism. The fact is - several hominid species went extinct in the last several million years.


3. Civilisations are rare

Millions of species existed on Earth, but only one was able to create technology. So, it is a rare event.Consequences: cyclic civilisations on earth are improbable. So the chances that we will be resurrected by another civilisation on Earth is small.

The chances that we will be able to reconstruct civilisation after a large scale catastrophe, are also small (as such catastrophes are atypical for civilisations and they quickly proceed to total annihilation or singularity).

It also means that technological intelligence is a difficult step in the evolutionary process, so it could be one of the solutions of the main Fermi paradox.

Safety of remains of previous civilisations (if any exist) depends on two things: the time distance from them and their level of intelligence. The greater the distance, the safer they are (as the biggest part of dangerous technology will be destructed by time or will not be dangerous to humans, like species specific viruses).

The risks also depend on the level of intelligence they reached: the higher intelligence the riskier. If anything like their remnants are ever found, strong caution is recommend.

For example, the most dangerous scenario for us will be one similar to the beginning of the book of V. Vinge “A Fire upon the deep.” We could find remnants of a very old, but very sophisticated civilisation, which will include unfriendly AI or its description, or hostile nanobots.

The most likely place for such artefacts to be preserved is on the Moon, in some cavities near the pole. It is the most stable and radiation shielded place near Earth.

I think that based on (no) evidence, estimation of the probability of past tech civilisation should be less than 1 per cent. While it is enough to think that they most likely don’t exist, it is not enough to completely ignore risk of their artefacts, which anyway is less than 0.1 per cent.

Meta: the main idea for this post came to me in a night dream, several years ago.


Comments sorted by top scores.

comment by CellBioGuy · 2016-10-01T23:41:19.404Z · score: 6 (6 votes) · LW · GW

Worth noting:

Possibly indicating that the end of the last glaciation rather than new invention drove the more or less simultaneous large-scale agricultural transitions that occurred all across the old and new world ~10k years ago.

comment by turchin · 2016-10-01T23:59:17.390Z · score: 1 (1 votes) · LW · GW


comment by CellBioGuy · 2017-01-29T02:49:56.683Z · score: 1 (1 votes) · LW · GW

Aaaaand I just saw a talk in which researchers found what look like barley starch grains in 150k year old Neanderthal dental plaque. Probably from wild-grain porridge.

comment by CellBioGuy · 2017-02-05T21:33:06.298Z · score: 0 (0 votes) · LW · GW

Potentially of interest:


comment by turchin · 2017-02-05T21:45:20.880Z · score: 0 (0 votes) · LW · GW

Thanks, fascinating!

comment by CellBioGuy · 2017-02-07T00:48:21.082Z · score: 0 (0 votes) · LW · GW

I've managed to find someone overlaying the ice core records of the last few interglacials for their own purposes, and although I think this diagram is poorly calibrated in terms of absolute temperature I think it is a reasonable diagram for comparing stability:


It certainly looks to a first glance like our interglacial is significantly FLATTER in terms of average temperatures (in the particular place in Antarctica that this core was taken) than those of the last 500,000 years. The ~23k year age of the reported seeds falls in the middle of the flattish bit of the red line before the rise at the start of the interglacial.

Interesting question if there is a hysteresis to agriculture.

comment by avturchin · 2018-08-08T12:58:33.107Z · score: 1 (1 votes) · LW · GW


comment by waveman · 2016-10-09T08:52:42.391Z · score: 3 (3 votes) · LW · GW

An extra data point. If we crash and burn, then earth will be too hot for multicellular life by the time the coal and oil are replenished. So the one and only industrial revolution has happened.

And given ~4,000m years of life so far and the heating only a few hundred million years away, we only just made it. Which suggests it is pretty hard to build intelligent life. Maybe because computation is very expensive so the gradient is steep. Robin Hanson has a paper on this point.

comment by Houshalter · 2017-02-06T05:41:01.280Z · score: 0 (1 votes) · LW · GW

It wasnt until relatively late in the second industrial revolution that coal completely replaced wood. And oil came very late. I think an industrial revolution could happen a second time without fossil fuel.

comment by waveman · 2017-07-11T01:02:37.495Z · score: 0 (0 votes) · LW · GW

Good point. However it would have petered out very quickly though as the wood was all burned.

comment by Houshalter · 2017-08-20T11:44:09.413Z · score: 0 (0 votes) · LW · GW

That's unlikely. By the late 19th century there was no stopping the industrial revolution. Without coal maybe it would have slowed down a bit. But science was advancing at a rapid pace, and various other technologies from telephones to electricity were well on their way. It's hard for us to imagine a world without coal, since we took that path. But I don't see why it couldn't be done. There would probably be a lot more investment in hydro and wind power (both of which were a thing before the industrial revolution.) And eventually solar. Cars would be hard, but electric trains aren't inconceivable.

comment by CellBioGuy · 2017-05-08T17:12:35.248Z · score: 2 (2 votes) · LW · GW

Of interest https://arxiv.org/pdf/1704.07263.pdf

comment by turchin · 2017-05-08T21:48:10.158Z · score: 0 (0 votes) · LW · GW

Thanks! I am started to explore a solution to survive the global catastrophe by placing archeological evidencse for future civilization on Earth - like digital hoards on the Moon.

comment by Tem42 · 2016-10-09T00:56:41.970Z · score: 1 (1 votes) · LW · GW

It is interesting to note that if we quietly pass away and 50 million years later intelligent lungfish build up a civilization, they would presumably have good evidence that we were here, and would have good reason to assume that civilizations arise about once every 50 million years on average. Our effect on the Earth has probably been great enough that they will not have significant evidence from previous periods to contradict this assumption. In the case of large scale planetary civilizations, only the first one is likely to be in a position to reliably notice a delay in the appearance of previous civilizations longer than the pause between themselves and the immediately previous civilization. Therefore it may be reasonable to believe that, if 10 civilizations arise on the average planet, 90% of them will believe that they are probably midway through a long succession of civilizations.

comment by Tem42 · 2016-10-09T00:26:55.183Z · score: 0 (0 votes) · LW · GW

If we are the only civilisation to exist in the history of the Earth, then we will probably become extinct not in mild way, but rather in a way which will prevent any other civilisation from appearing. There is higher probability of future (man-made) catastrophes which will not only end human civilisation, but also prevent any existence of any other civilisations on Earth.

I don't believe that this follows. It is surprising that we are apparently the only civilization to so far appear on Earth, but if we accept that we are, we should not assume that we have accomplished this by destroying the future.

However, while I feel strongly that this is this case, I do not feel confidant that I can express it in a way that would be understood by someone who does not agree with me.

If someone could explain clearly why I am right, or alternatively, why I am wrong, I would greatly appreciate it.

(For context, here is what I would write given my currently semi-formed understanding: "while it makes sense to compare ourselves to a time-line independent view of the world to test the probability that our assumptions about the world are correct, it does not make sense to assume that our assumptions about the world will guide the future.")

comment by mirefek · 2016-10-16T22:12:02.295Z · score: 0 (0 votes) · LW · GW

I agree with you, I think that I have the same problem with the article. Probability theory can not be used in such a way.

Every planet with some civilizations have a first one. People of the first civilization always wonder why they are first.

It does not mean anything for the future. Especially, it does not imply whether there will be other civilizations afterward.

comment by SquirrelInHell · 2016-10-01T20:22:06.278Z · score: 0 (0 votes) · LW · GW

Good job with the main idea. However your speculation about past tech civilizations on Earth, artifacts preserved on moon etc. seems only half lucid.

comment by CellBioGuy · 2016-10-01T23:32:37.624Z · score: 6 (6 votes) · LW · GW

My favorite crazy unlikely idea about that is that the Paleocene-Eocene Thermal Maximum 50 megayears ago - a 200k year pulse of high CO2 levels and temperatures in which the CO2 was added over a timescale of less than 10k years (potentially less than 1k years) and had an isotopic composition consistent with having been liberated from biogenic deposits - could theoretically be explained by all the coal and oil deposits of Antarctica being burned followed by some positive feedbacks kicking in.

(Most land of Antarctica never having been investigated geologically in any detail at all due to being under kilometers of ice) (And Antarctica at that time being completely unglaciated and relatively temperate despite being where it is now by then) (And subsequent glaciation having scraped most of the surface clean of anything that was on it at the time)

We have an advantage in that we evolved in the tropics - you can take a tropical animal and keep it warm near the poles by wrapping it in clothes. It's much more difficult to take a cold-adapted polar animal and keep it alive in the tropics...

comment by turchin · 2016-10-02T00:04:33.838Z · score: 3 (3 votes) · LW · GW

In the Trent's article even mentioned possible species of Dinos who may be able have intelligent explosion. http://www.strangehorizons.com/2009/20090713/trent-a.shtml

It means that we could find really interesting (and dangerous) things during excavations in Antarctica?

comment by CellBioGuy · 2016-10-02T20:05:25.305Z · score: 6 (6 votes) · LW · GW

In the hypothetical scenario in which there was something to find in Antarctica in the first place, given the thorough scraping the continent has gotten for 20+ megayears by kilometers-deep glaciers you can't expect to find much at all. The areas not covered by glaciers are generally mountains which erode - their modern exposed surfaces would have been quite deep underground at the time.

The sorts of things you could actually expect to find would be more along the lines of missing coal seams, long rods of long-ago-oxidized steel poking vertically through multiple strata into areas that would have held petroleum deposits at the time, really deep coal seams turned to ash in situ by underground gasification, hydrothermal features that concentrate copper and silver ore capped by weird craters that obliterate where the highest concentrations would have been with a big pile of copper-depleted gravel nearby. Perhaps odd isotope ratios in a very narrow sediment band if nuclear reactions were ever explored. The ecological effects you would expect on the continent are kind of overshadowed in the ocean sediment record by the worldwide climate event that the PETM represents (6C temperature spike, deep ocean hypoxia, phytoplankton death and repopulation).

It's worth noting that there are probably particular clades that are predisposed to being smart. There's a fascinating book out by Dr. Herculano-Houzel ("The Human Advantage") detailing recent work over the last decade examining brain structure across the mammals. She and her group found something fascinating: neural scaling laws differ from clade to clade. Mammals in general have a neural scaling law that if you make a brain 10x as large, it only has 4x as many neurons as the neurons on average increase in volume (partially due to longer connecting fibers). Primates break this though - all primate neurons are about the same size, which is remarkably small, the same size as that of a mammal that's like 10 grams in mass. A large primate brain is MUCH more powerful than a generic mammal brain of the same mass. Their recent work since that book came out indicates that birds also break that scaling law and have marvelously efficient brains - all bird neurons are approximately the same size like the primates, but what's more that size is 6x as small as those of primates. It is an interesting question if this would also have applied to dinosaurs, their close relatives who nonetheless were not under crazy selective pressure for low weight.

comment by WhySpace_duplicate0.9261692129075527 · 2016-10-02T17:18:34.003Z · score: 1 (1 votes) · LW · GW

The bit about EQ was particularly interesting.(Encephalization Quotient is the ratio of the volume encapsulated by the brain to the volume of the animal. It serves as a stand-in for IQ in extinct species. Humans have an EQ between 5 and 8.)

It should be possible to examine current organisms, and classify them based on EQ and whether they have opposable thumbs. For each category, we could look at what fraction display abilities like tool use, communication, vocabulary size, and passing the mirror self-recognition test.

For example, perhaps the average EQ=1 animal without opposable thumbs has a vocabulary of 2 (alarm cries and mating signals) and doesn't pass the mirror test. On the other hand, maybe half of EQ=4 animal with opposable thumbs display rudimentary tool use.

The actual range of abilities would give us our probability distributions for speculating about extinct animals. After some math to account for gaps in the fossil record 65+ million years ago, we should be able to estimate the probability that certain dinosaurs could use tools or pass the mirror test.

The hard part is determining the probability of developing civilization, given that a species displays certain marks of intelligence. We only have 1 data point, and anthropic principle makes it almost useless.

comment by CellBioGuy · 2016-10-02T20:14:09.804Z · score: 4 (4 votes) · LW · GW

EQ is NOT the whole story. As I just noted above in another comment, there is amazing work on brain architecture coming out of the lab of Dr. Suzana Herculano-Houzel, a scientist studying neural structure across the vertebrates. I recommend her book, "The Human Advantage" and all the papers to have come out of her lab recently.

Three important things:

1 - Neural scaling laws differ from clade to clade. In a generic mammal, a brain 10x as large has only 4x as many neurons so there is diminishing returns to brain mass probably due to the need to maintain long connecting fibers. Primates break this relationship - all primate brains are roughly equally densely packed, and indeed are as densely packed as a generic mammal brain from a very small mammal. Something changed in primate embryonic development upwards of 50 megayears ago predisposing large primates to have much larger numbers of neurons (Practical example: turns out the cerebrum of an elephant is roughly equivalent to that of a chimp and the largest whales probably correspond to early homo erectus).

2 - Humans are actually incredibly generic primates. All of the pieces of our brains fall right on the primate trend lines in terms of size and cell number - our cerebrum is not oversized, its just that the cerebrum grows faster than other parts with increasing brain size across all the primates. We just happen to have the largest neuron number. And also, humans fall right on the body size to encephalization quotient trendline of all the primates, with only 3 primates falling off the trendline - chimps, gorillas, and orangutans are below the trendline with brains much smaller than you'd expect for their body sizes. She hypothesizes, for very sound reasons explored in their papers and her book, that this was due to energy constraints because brain tissue is energetically expensive, and that humans were able to get back onto the generic primate trendline and have brains as big as you'd expect for a primate of our body mass once we started cooking and could support the energy requirements of brain tissue.

3 - Birds are another clade that breaks the usual brain scaling laws. Their neurons do not get bigger with increasing brain size, much like primates, except that their neurons are ~6x as small as primate neurons. Thus, it turns out that corvids and parrots are packing brains equivalent to many monkeys that their EQ would never suggest.

comment by WhySpace_duplicate0.9261692129075527 · 2016-10-02T17:32:18.739Z · score: 2 (2 votes) · LW · GW

As a side note, this might also be interesting, purely from a utilitarian standpoint. If insect suffering matters, that would completely dwarf all human moral weight, since there are 10^18 of them but only 10^9 of us.

However, perhaps we don't care morally about animals which can't pass the mirror test, on the assumption that this means they have no self-image, and therefore no consciousness. They could feel pain and other stimuli, but there would be no internal observer to notice their own suffering.

If that's the case, animal welfare might still dominate over human welfare, but by a smaller margin. Doing what I described in the previous comment would let us estimate the value of future life in general, if we can determine to within an order of magnitude or so how much we value animals with various traits. This is critical for questions like whether terraforming mars is net positive or net negative.

comment by scarcegreengrass · 2016-10-06T15:39:44.274Z · score: 1 (1 votes) · LW · GW

I actually drew up a spreadsheet to estimate this: https://docs.google.com/spreadsheets/d/1xnfsDuC0ddUxvKekGLJ5QA5nrXxzked7K-k6jqUm538/edit?usp=sharing

I agree with you about the numbers: If there were say 10^15 insects then their moral weight might be in question. However there are actually more like 10^18, which is huge even for very small per-insect weightings.

comment by turchin · 2016-10-01T22:03:28.464Z · score: 2 (2 votes) · LW · GW

I think that there is 3 ways to present these ideas in more rigorius form.

  1. Use Gott formula to estimate probability distribution P(N) that total number of civilizations on Earth will be N based on the fact that our rank number in all known civilization is n. (And in our case n=1, so N=2 has 50 per cent probability, N=4 has 25 per cent probability etc.) See the same calculation for original Doomsday argument. https://en.wikipedia.org/wiki/Doomsday_argument#Gott.27s_formulation:_.27vague_prior.27_total_population

  2. Use the fact that we don't know anything about past civilizations to put constrains on the informational traces T. T is function of civilisational technological level L and time distance to it t. So T(L,t) must be below some level of noticeability. T function is unknown to us but could be estimated as L/t which means that high tech and recent civilization will be more notable. Any risks from previous civilizations will also decay with time. So we could start to create math model form here.

  3. We could look on existing scientific literature. A lot of literature use observational data trying to explain original Fermi paradox, but it is surprising not true for past civilizations. There is no analog for "SETI search" for rare isotopes changes which could sign of civilization 100 million years from now here on Earth - or I don't know about this literature. I also don't know what is the rate of publishing of theoretically inappropriate results if someone randomly finds something which seems to be strange. There is attempt by late Russian author Kalandadze to collect evidences that some other hominids used fire here: http://www.evolbiol.ru/document/915 The work is controversial. I don't have special knowledge to assess it.

comment by scarcegreengrass · 2016-10-06T16:15:21.902Z · score: -1 (1 votes) · LW · GW

I would also contemplate the scenario that the human species might turn out to be less impressive than it currently appears, and is actually a fairly typical example of a successful Earth species. Most achievements that distinguish humans from eg plankton are in the future (eg space industry), not the past or present.

This might sound strange. Arguments in favor of this perspective:

• Homo sapiens is not the greatest species in terms of population or total biomass.

• Homo sapiens is not the only species to make tools, use agriculture, build buildings, or adapt to a variety of terrestrial habitats.

• Homo sapiens is not the first species to have a catastrophic impact on the atmosphere.

Arguments against this perspective:

• The human economy is currently doubling in scale every couple decades.

• No species (probably) ever reached the edge of the atmosphere before Homo sapiens.

(To clarify, i think this question is far from settled. But i think the idea that Homo sapiens will be smaller-impact than expected is more likely than the scenario that historical gods are representations of unknown prosperous civilizations.)

comment by turchin · 2016-10-06T18:16:37.821Z · score: 1 (1 votes) · LW · GW

If we look on humans as on typical species, we could use typical estimate of species life expectancy, which is several million years, and use it as human life expectancy. It is not bad.

But humans are definitely in the special point of their history and they could create a competitor soon (post humans or AI) and doesn't look good. Competitors are one of the main ways how species go extinct.

comment by tukabel · 2016-10-01T20:43:26.206Z · score: -2 (2 votes) · LW · GW

Well, we humanimals should realize that our last biological stage in the Glorious Screenplay of the Evolution of Intelligence is here solely for the purpose of creating our (non-bio) successor before we manage to destroy ourselves (and probably the whole Earth) - since the power those humanimals get (especially the ruling ones) from the memetic supercivilization living on top of the humanimalistic noise (and is represented by a fraction of per cent that gives these humanimals essentially for free all these great ideas, science and subsequent inventions and gadgets) is rapidly becoming so huge (obviously, exponentially) that we have simply no chance to manage the upcoming nano revolution... already nuclear bombs were just-just - now imagine affordable one dollar DYI nuclear grenade every teenager can put together in the garage... nanobots will be orders of magnitude worse.

So, maybe we are first on Earth, but not necessarily last... if the Singularity does not make it. We are the threat, not "rogue AI".