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...
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.
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.
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.
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.
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.
I think that there is 3 ways to present these ideas in more rigorius form.
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
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.
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.
Good job with the main idea. However your speculation about past tech civilizations on Earth, artifacts preserved on moon etc. seems only half lucid.
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...
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?
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.
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.
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.
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.
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.
I think that there is 3 ways to present these ideas in more rigorius form.
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
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.
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.