There Have Probably Been Aliens
nytimes.com
nytimes.com
This is terribly silly. It reminds me of the Onion talks:
"Step 1: Devise an idea to create a car that runs on compost. Step 2: Create the car. We’ve already completed Step 1. We’re half way there."
Increased certainty on three of the seven factors is irrelevant, because 99% of the uncertainty is concentrated in the other four. Specifically, the odds of abiogenesis are ~1/2^n, where n is the complexity in bits of the smallest self-replicator. n is bounded below by ~100 or so (or it would have happened in a lab somewhere), and is bounded above by ~1 million (the smallest existing bacteria), so we know it's somewhere in there. But where? We have only the vaguest guesses.
"Specifically, unless the probability for evolving a civilization on a habitable-zone planet is less than one in 10 billion trillion, then we are not the first."
"One in 10 billion trillion" sounds like a very large number, and it's put in italics for emphasis, but in information-theoretic terms it's tiny. log2(10^22) is just 73 bits. If all that we know about a number is that it's somewhere between a hundred and a million, saying that X would imply it's higher than 73 (well technically 73 + log2(#incidences of molecular combination), so probably a few hundred) is not a disproof of X, nor really even much evidence against X.
Nevertheless the progress on the other factors in the Drake equation is very interesting and impressive.
I disagree with this.
It seems that, from what happened to other planets on the solar system, that nothing happened on Earth too much out of the ordinary. Mars had a similar story (except for the whole Moon coming out of a giant collision), and had water. But maybe it was too small to keep warm for enough time
Earth had 5 mass-extinctions, that "reset the game" before we got to humans. Doesn't seem too far fetched to me
I really don't buy that Earth is one in a billion unless Mars is one in a billion as well. Maybe one in 1000? One in 100000?
And that's limiting intelligent life to what we know. Yes, maybe the ideal speed of chemical reactions (for intelligent life) happen around 273K, or maybe there's another way
Anyway, what reason do we have to believe that Earth is special 2X? That we happened to have the right conditions plus some randomness occurred against all odds that gave rise to life? Why is that a rational proposition?
We know the chemical elements and processes that give rise to life, and we know why Earth is a suitable place. I suggest that, given the right (e.g. Earth-like) conditions, formation of life is not only more likely than the existence of the conditions, but the formation of life may even be likely overall. Hawking has expressed this possibility. [0]
There is fossil evidence suggesting that some forms of life existed on Earth as few as 500 million short years after it was formed. So, what are the odds that one astronomically improbable event (creation of a hospitable environment) was followed in such a short period by another alleged astronomically improbable event (abiogenesis)?
But it takes a lot of time to get to "life" as we know it.
(Now the right conditions are probably not what you have on Earth today except in a couple of places)
Life on Earth is at least 4Bi y.o. http://newsroom.ucla.edu/releases/life-on-earth-likely-start...
I think what will really help us to get at a better estimate
is to answer the question whether there exists life in our
solar system that evolved independently of that on Earth.
There's no hard reason why another, orthogonal family of life couldn't coexist with DNA/RNA life. We have 10^7 extant species of DNA/RNA life; that's an existence proof that hostile, competing "types" of life can coexist. Suppose we found terrestrial "XNA life" with a biochemistry totally unrelated to anything else, with no possible common origin or lateral gene transfer. Then we would know life on Earth developed independently N >= 2 times, instead of N >= 1. That would change a lot; we could update P(life | Earth-like planet) from the subjective probability range [10^-Graham's number, 1) to something more like [10^-4, 1).
What's really surprising is that this is completely untested! We genuinely don't know if there's "alien" life on Earth, because we don't know how to look for it. There's no black-box tool to approach unknown biochemistry:
Some have postulated the existence of a 'shadow biosphere'
on Earth, teeming with life that has gone undiscovered
because scientists simply don't know where to look. It could
contain life that relies on a fundamentally different
biochemistry, using different forms of amino acids or even
entirely novel ways of storing, replicating and executing
inherited information that do not rely on DNA or
proteins. [...] The trick is deciding what to look for and
how to detect it. The usual way that researchers search for
new organisms — by sequencing DNA or RNA — will not pick up
life that does not depend on them.
...We could even be oblivious to unfamiliar forms of life
right under our noses...
v2.0 life would have to evolve in the changed environment - which would be considerably less hospitable, because the most useful chemical processes and energy sources will be colonised by v1.0 life.
v1.0 life will (more or less literally) get the low hanging fruit. v2.0 would have to evolve around the edges, which means the probability gradient is higher and therefore less likely.
So although it's a very valid point I'm not sure if it's a sufficient argument against the hypothesis of having two independently evolved and fundamentally different types of life on a given planet.
This would be good stuff for a science fiction story as well.
The only way to die if a UV ray split you, or you fall into a volcano (there are no fire, because the atmosphere has very few oxygen), or a nasty oxygen molecule reacts with you, or ...
Well, there are many ways to die, but they are not targeting you, so perhaps you can hide from the sun under a rock. Or to be more clear, since you doesn't have any kind of senses or mobility, perhaps you are lucky and get beached under a rock. Perhaps the rock also makes a nice place to concentrate other molecules during the low tide.
Perhaps it's not a good idea to be near the surface and it's better to be lucky and get near a underwater sea vent with tasty hydrogen. I think the details of the first steps are not clear for anyone (in particular for me).
Once a stupid life for appears, the first thing it would do is eat all the free food. In particular, before the first life form the half of the amino acid were L and half D. We have used all the L amino acids (and created many more than the original supply), and we have also eaten all the original D amino acids. So there are very few of them floating around freely, it would be very hard to start an alternative D-tree.
A new life form will be targeted by the existing life form, like the free D amino acids. The competition will be extremely hard. So I think it's a winner take all task.
Moreover, then some moron decides to release a lot of oxygen to the atmosphere. Oxygen is extremely toxic for most life forms, and more toxic for isolated molecules that are barely alive ...
About the shadow biosphere: Perhaps we (humans) can't detect or identify them, but the bacteria and archaea can probably live there and eat them barely-alive. Our cousins can keep all the out-of-tree competition at bay.
If you are the first almost live form, you have plenty of
time, and can evolved in an environment that has plenty of
food. Something like the brown goo of Titan, with lots of
hydrocarbons and other small molecules that you can pick up
for free.
That's likely generic for pre-biotic environments. Planets don't naturally form redox gradients; if there's a large redox potential, that's reactive chemistry, which will react away to equilibrium over geologic time. It takes work to maintain such a gradient; for example, Earth's oxidizing atmosphere is actively maintained by life. Oxygen is geologically removed from atmospheres, reacting with exposed rock surfaces (oxygen weathering). It takes active expenditure of work (solar energy) to keep it existing.
There is some chemical energy in abiotic planets, but only small amounts, at very low power levels compared to Earth's aerobic biosphere (which eats something like 10^14 watts!). There's photochemistry caused by solar UV light, and there's atmospheric lightning (which is a major player in the Earth's N2 cycle). Most important is geochemical energy; i.e. primordial chemical gradients that aren't yet at equilibrium, because the two reactants are physically separated by rock layers. On Europa for example, a very slow process brings rocks into contact with the ocean, where slow serpentinization reactions can occur: oxidation of Fe++ to Fe+++ by water, with the production of H2. This would be the food source of Europa life, if it's there.
I'm not sure if this is for or against your comment, but I hope you find this interesting:
"A cave in Romania that was sealed for 5.5M years" http://www.bbc.com/earth/story/20150904-the-bizarre-beasts-l... HN discussion: https://news.ycombinator.com/item?id=11682816 (889 points, 38 days ago, 163 comments)
And the author even asserts it's "irrational" to think real-world probabilities are this small!
It's easy to construct "unreasonably" small probabilities: take a few small ones and multiply them. If you path-sum all the evolutionary state transitions summing to P(intelligent life|planet), is it a shallow graph with many alternatives (additive probabilities), or a deep graph dominated by long, conjunctive sequences (probabilities multiply)?
If the odds of abiogenesis are 1/2^128, and if that is the source of life, then we're the only life in the Universe. As the article indicates, there are only 2^73 stars.
It took modern astrophysics to determine the origin of the chemical elements. We observe stars (and) we know what goes on in their center. They explode, laying bare their contents. And what we have discovered is that the elements of the periodic table -that which we are made of- derive from the actions of stars that have manufactured the elements, exploded (and) scattered their rich guts across the galaxy, contaminating or enriching gas clouds that then form a next generation of stars populated by planets and possibly life.
And so, when you look at the ingredients of the universe, the number one ingredient is hydrogen, next is helium, next is carbon- sorry- hydrogen, helium, oxygen, carbon, nitrogen. Those are the top ingredients in the universe. And you say well, okay, that’s kind of cool. Well, and you look at Earth- cause we like thinking of ourselves as special- we say Oh! we’re special! What are we made of?
Well what’s the number one molecule in the body? It’s water. But what’s water made of? H-2-O. Hydrogen and oxygen. Hm. Hydrogen and oxygen. In fact, if you rank the elements in the human body, with the exception of helium, which is chemically inert- useless to you for any reason other than just to inhale it and sound like Mickey Mouse. You can’t die from helium unless that’s all you breathe. So, number one in the human body is hydrogen. Matches the universe. Number two? Is oxygen. Matches the universe. Number 3? Carbon. Matches the universe. Number 4? Nitrogen. Matches the universe. And for each of us the fifth element- other- is the same in both places. Ok? Other.
So, we learned in the last 50 years that, of course, not only do we exist in this universe. It is the universe itself that exists within us. And had we been made of some rare isotope of bismuth, you’d argue and say hey, we’re something special.
From https://tiainkorea.wordpress.com/2012/04/22/a-fascinatingly-...
Also, this is the most interesting explanation to the Fermi paradox that I've seen: http://accelerating.org/articles/transcensionhypothesis.html
Most common elements in the human body [2]: Hydrogen, Oxygen, Carbon, Nitrogen
I agree that we can skip helium and neon since those are noble gases, but I do find the lack of iron interesting.
[1] https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elem...
[2] https://en.wikipedia.org/wiki/Composition_of_the_human_body#... (look for table, sort per atomic percent)
However, iron does play an important role in life as we know it, even today. Earth's molten and rotating iron and nickle core is what creates our magnetosphere that shields us--and presumably early life--from deadly solar radiation.
I would have thought the iron in mammal blood would come to mind first, but other aquatic life forms have copper-based blood, so it's not exactly required.
Statistical mechanical entropy and information theoretical entropy ('complexity in bits') are not the same quantities! But even if they were, your expression would still be incorrect because living system are definitionally not at equilibrium - so equilibrium statistical mechanics (whose predictions you are using to get that expression) does not apply.
No one is surprised when convection rolls spontaneously form as they boil a pot of water. But equilibrium statistical mechanics predicts that this should be extremely unlikely as convection roll states have very low entropy. That is, of all of the ways that the molecules in that pot of water could be oriented, vanishingly few of them correspond to convection roll states, where several Avogrado's numbers worth of particles conspire to all swirl around in a coordinated fashion to dissipate the heat of the burner faster than would occur just by diffusion.
The origin of life is very much analogous to the formation of convection rolls in the pot. And I believe is far more common than classical predictions imagine it to be - nearly everywhere there is an energy gradient in the universe, you will probably find life.
Citation: I have a degree in physics
Of course it can be easy to over-do the analogies between things like convection rolls and the emergence of lipid bilayers (or whatever). However, the origin of life necessarily came about through purely physical processes and only once that bootstrap phase was over did evolution come into play as biological systems took over acting upon themselves.
As I understand it the idea is that a closed system that is driven far from equilibrium by a constant influx of energy can undergo 'symmetry breaking' where the symmetries of the system are changed. So the symmetric situation of the boiling pot is broken such that convection rolls are formed - which is new structure.
Similarly, a uniform soup of primitive chemical compounds could have been broken into less-uniform patches by some energy gradient (black or white smokers, for example). This diversity of chemical conditions then helped to form the initial replicators that could then further exploit various temperature, chemical, or proton gradients to create primitive life.
This assertion (whether thermodynamic entropy and information theoretic entropy are equivalent) is an ongoing controversy open to debate - it shouldn't be stated as fact. See wikipedia for (a summary of) both sides of the story: https://en.wikipedia.org/wiki/Entropy_in_thermodynamics_and_... (specifically the #Theoretical_relationship and #Criticism sections)
As an analogy, if I make a huge number of random files on my computer and execute them, the probability of getting a self replicating computer virus is really low. And one that successfully spreads itself to other computers over the internet should never happen.
If the first successful computer virus is 100 bits long, then probability of finding it in a single random search is 1/2^100. Which is just incredibly small and should never ever happen.
There could be 10 different ways to make a virus N bits long. There could be 1000 ways to do it in N+1 bits, and a billion ways in N+2.
The relationship between how many possible successful viruses exist to number of bits doesn't have to scale by any obvious pattern.
There could be a magic threshold where if you're shorter than that you don't work.
For ex, maybe a valid file has to be at least 100 bytes, or the OS can't treat it as a file. Any random file 100bytes or longer could have a 10% chance of being a virus (the actual number depends on how the os works).
This would mean a really high chance of randomness creating a virus, even though N is 100.
The probability of vitality depends on the specifics of the operating system, and we can't infer it by looking at the size of the smallest possible virus.
There is a reasonable theory that I remember discussing/reading once that proteins may have started out as long sequences and were then selected for shorter more stable versions. Presumably the early proteins were partly disordered, and only optimised for having stable cores and domain structures later on.
In any case, it is not as simple as the number of bits in a program, as macromolecules are not 'just' software, but actual physical devices that have to (self)-assemble and carry out functions at various temperatures, pressures, pH, etc.
Saying that "the odds of abiogenesis are ~1/2^n" isn't an assertion of fact, it's merely defining n = -log2(probability of abiogenesis). (Of course, the probability of abiogenesis occurring in any particular body of water is not a constant, it depends on conditions; but all the oceans on Earth are only 80 binary orders of magnitude bigger than a single mL [1], so n for a lab experiment and n for the entire Earth can't be more than a couple decimal orders of magnitude different, so it's immaterial.)
In other words, your argument about convection rolls is an excellent argument that the n for abiogenesis is much, much lower than -log2(probability of organic molecules in solution spontaneously assembling themselves into bacteria), which grandparent claimed is ~1 million. I have no reason to believe ~1 million is accurate, but I don't care, because grandparent has convinced me that the upper bound is many orders of magnitude greater than 73. Your argument that n could be much less than that upper bound is convincing, but unless you're arguing it's so much lower that it isn't much greater than 73, grandparent's counter to the paper still holds.
[1]: http://www.wolframalpha.com/input/?i=log2((volume+of+ocean+i...)
Quote Martin Amis's The Information:
“The history of astronomy is the history of increasing humiliation. First the geocentric universe, then the heliocentric universe. Then the eccentric universe – the one we’re living in. Every century we get smaller. Kant figured it all out, sitting in his armchair. What’s the phrase? The principle of terrestrial mediocrity.”
People base the idea that there should be other life in the universe on the fact that life developed at least once, which is here on earth. The odds are it would happen either 0 times or many times, but not exactly once.
This argument is reasonable if there is one universe. Another scenario is that there is some god awful large number of universes (for round numbers let's say 10^1000 raised to the 10^10000 power, which would be a huge underestimate), and that most of these universes contain no life, because the odds of life developing are also very, very small. We ARE special in that we are viewing one of the small fraction of universes that has life, because if it didn't we wouldn't be viewing it. This allows for life to exist exactly once in our universe. There could also be universe where life developed independently more than once, but the odds of us being in that universe are very small relative to the odds of being in a universe with one life.
But how would there be many universes? Here is one possibility that is surely controversial. In quantum mechanics, things happen in parallel. Is that electron spin up or spin down? It is both, but the electron in one state is not influenced by the electron in the other state. Each exists wholly on its own. This is true whether you believe the Stockholm or the Many Worlds interpretation of quantum mechanics. These two cases only differ when some special life form makes an observation, in which cases something very dramatic happens in the Stockholm interpretation (which is observationally indistinguishable from the "nothing different" that happens in the Many Worlds interpretation). If we think about the simplest form of life that can not make observations rather than looking for human-like life, the distinction between Stockholm and Many Worlds is mute. These parallel states of the system form our many universes, some that contain life and some that do not.
https://en.wikipedia.org/wiki/Von_Neumann%E2%80%93Wigner_int...
https://en.wikipedia.org/wiki/Many-minds_interpretation
More precisely, these interpretations require consciousness, but we can take that consciousness requires life.
"There are more than 10^22 planets, therefore ETI probably exists[ed] if P(intelligent life|planet) > 10^-22".
Specifically, unless the probability for evolving a
civilization on a habitable-zone planet is less than one in
10 billion trillion, then we are not the first. [...] In
other words, given what we now know about the number and
orbital positions of the galaxy’s planets, the degree of
pessimism required to doubt the existence, at some point in
time, of an advanced extraterrestrial civilization borders
on the irrational.And yet (either way) I'm not sure it really matters. No human has left our own planet for longer than 437.7 days [3]. Say they're right, though. If an alien race exists, we're still a ways from being able to do anything about it. Unless we can make it there in 1.198 years. If that alien race can make it here, awesome. Let's talk then. If they can make it here and are hostile, then it's been swell. See you on the other side. Probably.
[1] https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole
[2] https://en.wikipedia.org/wiki/Bathyscaphe_Trieste
[3] https://en.wikipedia.org/wiki/List_of_spaceflight_records
Could be confusing if you're used to the inverse comma/period from what we use in the US (comma=thousands, period=decimal).
After working with probability theory and combinatorics a bit, you realize probabilities much smaller than this occur naturally all the time. It might be hard for people not familiar with that to appreciate this, and be wowed by such a small number.
The thing is that independent probabilities multiply together, and so approach 0 exponentially fast. The probability of winning the lottery is of course very small. But there are so many people, that someone wins a lottery every day.
But the probability of winning the lottery twice is really small. The set of people that have won twice is a very small set indeed. And the probability of winning 3 times is so small that we should expect it to be a sure sign of corruption of the lottery, or intervention by supernatural forces. It's also about 1 in 10 billion trillion.
It seems to me that the evolution of intelligent life from nothing, also requires many things to go right. We don't know what all these things are, and we can only guess what their probability is. But if even a few of them have relatively small probabilities, then the probability of all of them happening could easily be much lower than "1 in 10 billion trillion".
There are many candidates for this so called "great filter". Some ideas I think are plausible are the evolution of multicellular life. The Earth was around a very, very long time before multicellular life formed. And it's believed to have required some weird coincidences like a parasite evolving into mitochondria.
Another candidate is the evolution of intelligence itself. Most animals aren't intelligent. Intelligence doesn't actually seem to be very correlated with fitness beyond a certain point - and reducing brain size is actually beneficial. Animals with brains were around for a very, very long time before anything like humans appeared. Some scientists believe that humans required a really weird set of conditions to evolve. There are theories that we are a case of accidental runaway sexual selection, like the peacock's feathers.
And there are many other factors we can't possibly know, that might be unique to Earth and rare on other worlds. We also don't know a huge amount about the evolution of early life. Getting from RNA self replicators to the complicated machinery of the most recent ancestor was no small feat.
Given the analysis, I would expect that bacteria and archaea, are present on any world with liquid water and a threshold amount of heat. Which would include Mars, Europa, and probably Io as well. There are a number of forms of bacteria living in the ionosphere which could be dropped on to Mars and they would do just fine there.
The odd bit comes from the origin of eukaryotes. Which, according to Lane, might arise if archaea were endosymbiotically living inside bacteria. That works but he doesn't offer any suggestion of what caused it to happen the first time. And he makes a reasonably good case that what ever it was that caused it, happened exactly once in the 4+ billion years of the planet and 3+ billion years of bacterial life roaming around.
http://ronbarak.tumblr.com/post/25996121029/life-is-it-inevi...
In the book he expanded on what was needed to make the jump to complex life and his opinion on how unlikely it was. He made a case for how only a relatively small time window was available for it to happen at all.
I second the rec!
http://io9.gizmodo.com/11-of-the-weirdest-solutions-to-the-f...
In the long-run (of millions of years), the two most likely outcomes for humanity are extinction or galactic colonisation. If we do colonise the galaxy, we'll prevent any other intelligent species from evolving within it (by fully occupying that ecological niche.) If we go extinct, we'll leave that niche open for another species to maybe one day occupy as we would have failed to do. The galaxy is likely a natural hard limit for our species, since while interstellar travel is difficult it is arguably possible (not with present day technology and economics, but potentially within a few centuries from now), but intergalactic travel is likely never going to be possible.
Even if these authors are right that other intelligent life once existed in this galaxy, it's almost surely extinct by now. If that's true, it makes their conclusion profoundly pessimistic – the more ruins of dead civilisations this galaxy contains, the greater the likelihood that we'll meet the same fate as they did.
I think we'll always be alone in the universe. And it's probably better that way.
Your reasonning is based on many assumptions. Look at us. When did we discover how to fly ? When did we landed on the moon ? Human evolution in science and technology mastering is evolving exponentially. Things can happen much faster than we thought.
Another question is why is the UFO phenomenon consistently discarded in the reasoning ?
I discount UFOs because I believe the alternative explanations–such as natural atmospheric phenomena, secret testing of military aircraft, confusion, hallucination and delusion–are collectively much more probable than the hypothesis that extraterrestrials have visited us.
I understand but the reality is undetermined. So assuming that UFOs are not real or ET manifestation is taking a risk of error.
My knowledge of the UFO phenomenon is different as I'm very close to the author of the following articles [1](http://www.meessen.net/AMeessen/Propulsion.pdf) [2](http://www.meessen.net/AMeessen/Evidence.pdf) [3](http://www.meessen.net/AMeessen/Production.pdf).
While I agree that a priori we don't know if we can attribute any reality and seriousness to the UFO phenomenon, these studies shows that we should. The author applied the inductive process. If the UFO phenomenon is real and the manifestation of unconventional flying objects, they must respect the law of physics that we know. The author investigated the a priori uncertain data to determine if it is possible to explain what is described by using the law of physics that we know and are valid in our environment (air, water, etc.). The only liberty degree accepted is that since the UFOs may not be of human origin, they could use the laws in an original way not yet known to us.
The referenced articles describe the result of this study. The conclusion is that it is possible to explain the propulsion mechanism of UFOs and its described properties. The mechanism is not yet used by humans and require a supraconducting surface at room temperature and above.
This is a theory explaining the observed phenomenon. The normal scientific process should now be to test that theory. This is the work of an experimentalist, not a theorist.
Of course this doesn't tell us anything on the real origin of the phenomenon. But its theorical validity give credibility to it. Since many reports signal the presence of non human looking beings, this give credit to the ET origin. Finally, supraconductivity at room temperature is not yet mastered by humans. I suppose it would be known by now if it was the case.
Why do these ET behave as they do ? I have no idea. One thing to keep in mind is that the rules and optimal strategies may be different once space travel and energy is not a problem anymore. There may be no benefit in colonizing the galaxy. There is enough space for everybody. My conclusion, influenced by the results of the author is that what matters is to be able to ensure the survival of ones civilization. This means that scientific and technological advance is primordial and determinant as we can see with the war in Syria. We can also see that colonizing doesn't work unless the population is fully under control. This may give credit to the abduction side of the UFO phenomenon, but I'm much more careful on this subject because we have much less data and independent data sources.
I think people underestimate how low probabilities can really be. According to wiki the shortest self-replicating RNA is 165-bases long. Even if you convert all observable universe in RNA this is still not enough for this RNA to form by chance (4^165 is much larger than number of atoms in observable universe).
Which kinda suggests there is either a mechanism that promotes that, or there are other, easier paths to get self replication. Otherwise we mostly likely wouldn't be here.
> A million monkeys typing on keyboards will eventually write shakespeare. But it will be longer than the universe before they even type a single sentence of it correctly.
All it takes is _one_ tiny selection force to blow this argument out of the water. For example, if only _a single_ correct letter is retained from each attempt, the problem gets exponentially easier with every iteration, making the expected time to generate any work linear in its length.
But aren't those chances constantly being created, on the scale of uncountable -illions of interactions of molecules that happen every second, across the billions of square and cubic kilometers of the surfaces and oceans of those billions of planets, across billions of years?
I mean, doesn't that improve the odds just a little bit?
It just seems pretty obvious that we have an ever increasing set of opportunities to extinct ourselves, and therefore the probability of a civilisation ending disaster only grows.
All the aliens either blew themselves up, starved, or are the kind of incredibly boring, mind-numblingly conservative people you wouldn't invite to a local cluster cocktail party.
Oh, either that or civilisations tend to disappear up their own simhole.
Or that might accelerate the end of civilization due to our inherent tribalism - the US isn't quite a backup of Europe as a 16th century European would have imagined. Who is to say there won't be a Planetary Mutually Assured Destruction?
The Expanse (books and TV series) explores some themes around planetary identity & politics in a fictional future where Mars and the outer solar system has been colonized and Earth is seen as a meddling 'old country' by some.
Sensationalist title aside, the article actually plays it extremely safe, by asserting a very high probability of extraterrestrial civilizations having been existed somewhere in the past.
But even so, there are potential problems where that might conflict with observation. I'm not generally a fan of these "alien civilizations must construct huge machines and must have a huge energy output" assertions, however, all it would take is one of the previous civilizations to have built something we can recognize. Sadly, nothing has been found, neither artefacts such as probes, nor radiological evidence in the sky.
Now, there are many possible reasons for why we haven't found anything yet, first and foremost being that the galaxy is vast in both time and space. But if I forced myself to be especially pessimistic, I would say that the probability of abiogenesis might be way smaller than even our bleakest estimates.
My logic is that intelligence (as defined above) is clearly rare here on earth where life is prolific, hence by no means a certain development of evolution. I wouldn't be surprised if we're the first in the universe where the conditions are certainly less hospitable for life.
This game of probability doesn't only depend on the sample size, but also on what you're looking for. For instance, you can say that if you find a purple grain of sand, and you know there are trillions of other grains, then you'll be sure to find other purple grains. But what if the purple grain has written on it "hello how are you" by sheer chance. You'd probably never find another grain of sand with that same writing.
And then you can say, "us being the first is egocentric". Well, but we're the first (on earth) when it comes to building radio stations, so we clearly won that lottery big time. Is it such a stretch to say we won the lottery in the universe as well?
Who told you we're "the first when it comes to building radio stations"? There could be 200 other explanations for "radio silence" from advanced civilizations (if they exist).
That's par for the course. That's how evolution works. And we're also gonna be the last on earth (we or our evolved successors), because we have the evolutionary upper hand.
But that doesn't say much for other planets. We expect them too to have billions of species and a race to produce an intelligent being too.
My point is that intelligent life as defined above seems not to be a certain development of evolution. I showcased the evidence for that. You seem to think that it is, but you didn't argue why - other than "it happens so it will for sure on other planets as well".
There are tons of other traits that are singular in the evolutionary tree, simply because they didn't stick for whatever reason. If intelligence was as common as binocular eyesight, say, then we'd see it appearing in all kinds of very different species.
The main issue I see is that there were other species that were close to as intelligent us, but we out competed them and they went extinct.
I wouldn't be surprised if there was a sort of "first one wins" effect where the first species to reach a certain level of intelligence quickly (compared to the time it takes to evolve that level of intelligence) comes to dominate the planet wide eco-system on a level far beyond every other species, thus preventing the development of other intelligent species.
Even if our close relatives had similar intelligence and we outcompeted them, it's still safe to say that intelligence (as defined) appeared in only a small branch of the evolutionary tree.
Why don't we see species underwater building radio stations? There's lots of life diversity underwater and they certainly weren't in our "competing" ground (being underwater) so they could've developed intelligence independently... but didn't. That's my point.
And define what you mean by "high probability", I would agree that intelligence (as defined as building radio communications) does not have a high probability of evolving compared to binocular sight.
What I am getting it, is I would not be surprised if intelligence (building radio communications) was like a race. A race only has one winner. Just because a race may have a thousand contestants, does not mean that the probability of there being a winner if 1/1000. Rather the probability of there being a winner goes to 1 as the duration of the race increases.
Or its like concluding that because life only appeared once on this planet, its very unlikely that life could have appeared at all. Another hypothesis is that once life appears, it makes it very difficult for new life to appear by preventing the conditions that lead to abiogenesis. For example maybe chemical evolution can not occur, because in all places where it would the are living organisms that interrupt the process because those chemicals are useful to the organism.
Similarly, I Humans have an unprecedented degree of control over the evolutionary trajectories other organisms. Maybe other apes, if left alone for hundreds of millions of years would evolve into a species that develops radio communications. But organsim's need evolutionary pressure to evolve, and humans really, really like preserving species. If a species of apes start dying off due to some evolutionary pressure, rather than let nature take its course and let the apes which can survive that pressure out compete the others, humans will intervene to keep them around, and as a result they will remain stagnant evolutionary.
And … nothing is provided to indicate that said probability is higher than that.
For me, that's a red flag. I can't know the probability of a phenomenon which my existence depends on just by observing my existence alone, because I can't observe all of the cases where the phenomenon does not occur and I do not exist.
> the authors essentially claim to know the probability of their own existence
The "quantity of interest" is the probability of aliens, but not the probability of aliens in all possible worlds, but rather the probability of aliens in this world. In this world, the probability that the authors exist is 1.
Now, if you are being a strict Bayesian then the probability of the coin being heads is never quite 0 or 1 because there is always the possibility that your eyes are deceiving you, or you are suffering from delusions or some equally unlikely contingency. But I assume that's not what you mean, and that you accept that humans do in fact exist in this universe, in which case the probability that humans exist in this universe is exactly 1. P(A|A)=1 by definition.
To assume that a collection of beings which have obtained the ability to travel amongst the stars would focus their attention on a single species on a single planet is fundamentally selfish.
What resources does our earth contain that are not (more easily) obtainable elsewhere? If Drake's equation "holds", then what novelty do _we_ provide?
Us. If the probability of an intelligent species developing are that low that there might only be a handful of intelligent species in our galaxy then making contact with each of them is extremely interesting if they are as curious as we are.
Morality - they might be utilitarian and desire to relieve the suffering of other sentient beings. Or force their weird alien morals onto them.
Competition - we might not be a threat now, but given a sufficiently long time, we could evolve into one. If they really don't care about us, it would cost them very little to exterminate us early.
If we were traveling amongst the stars today, with our values and morality as they currently are, and happened upon a world of what we'd consider to be primitive life, we'd probably scoop some up and put them in a zoo, or broadcast them on TV. We'd want to study them, learn what makes them tick, maybe try to see if communication was possible, but in the end, we'd get entertainment value from them.
Even if we left them be and studied from a distance, the human race would be fascinated. New life! A new place! We like new things. The news would cover these creatures ("Are they a threat to humanity? News at 11."), they'd be woven into stories and shows and movies in one form or another. If we could safely bring them back, people would want to see them in person.
We'd get a lot of entertainment value out of these new creatures. We're a curious race who manages to get bored of spectacular things quickly, which is a large reason we continue to innovate and push forward.
There's no way to know for sure what would motive another intelligent race to advance to the point where they'd reach for the stars, but if any of them shared a degree of curiosity, I doubt they'd pass us up if they found us. We'd be something new for them.
Maybe we'd end up in their stories, their drawings, their videos, or even their zoos. Maybe they'd be interested in how we smell, or the way we dress and decorate ourselves, or the things that we watch on TV. Our languages, our fights, our culture. Or maybe just the way we go about our business, missing some big cosmological truth that's so obvious to them, as if we're adorable little children.
Maybe we'd provide just enough entertainment value to be worth a quick trip. Or a long stay.
A super-intelligent species would have no trouble modelling and manipulating human politics from behind the scenes.
It's naive to assume that an interaction will look like the old explorer or conquistador model - a ship arrives, someone gets off it, and then demands to talk to the chieftain, or starts killing people and blowing shit up to make a point about power.
The set of all possible - and effective - interactions which doesn't look like that is much bigger than the set that does.
hehe, you forgot humanity's favorites:
enslavement
resource plundering
empire building
The "focus their attention" implies some total devotion. They could just study us or just come visit for the experience.
Like we "focus our attention" to thousands of wild life, with documentaries and shelters and various research, despite having obtaining the ability to travel among the continents (and even to the moon) and being much smarter than them.
Second, who said they have "obtained the ability to travel amongst the stars" in the first place? If they exist, they could be just like us, or even like us back in ancient times. And in that case, one would imagine they'd totally "care" for us, if they only could find us (like we care as to whether others exist or not).
Excellent 50 minute forum with 3 of the greatest brains of the 20th century.
God, The Universe And Everything Else: https://www.youtube.com/watch?v=HKQQAv5svkk
Maybe we are not special at all.
https://www.quantamagazine.org/20140122-a-new-physics-theory...
If intelligent life is at all likely, there ought to be many civilizations that have had millions of years technological head start on us. Given one species with galactic ambitions, but technology only modestly beyond ours, it would only take them one million years to colonize the entire galaxy. So why do we not see any evidence whatsoever?
This is the Fermi Paradox.
Comments seem sufficient for me to realize I needn't have bothered.
Science requires a theory and experimental validation.
The existence of aliens has been postulated by a crazy monk that also invented the concept of monads. It is much more metaphysics (religious thinking) than physics.
It strikes me as odd that most of flawed science is coming with the same flaws as religious thinking.
You'd be surprised. That's 19th century thinking about science, and not really how science works in practice most of the time.
And yes there has been a lot of flawed science in the XIXth I am aware of it ... like the theory of the ether that Einstein dispelled through experimentation, or the superiority of some "races", or the morpho-psychology...
Interesting nonetheless.
Perhaps I'm missing your point?
The quantum machanics behave disturbingly close to lazy evaluation - so this would not be surprising too.
Everyone of us is a god to a colony of ants.
The probability we are in a simulation depends on a bunch of assumptions. Assuming specifically we are asking about a "historical simulation", that the parent universe is identical to ours, we can change the question. Instead ask what is the probability we will someday create historical simulations of our past.
Technology certainly seems to advance over time, and the upper limits on computational power are extremely generous. So it's possible we could someday have the technology to do it. Assuming that, then it just depends on the probability you think we will want to make simulated beings. Something about that seems kind of sick and immoral, so I am skeptical of that assumption.
But if it is true, then the probability you are in a simulation is extremely high. Because the number of simulated beings could easily be orders of magnitude higher than the number of actual 2016 Earth inhabitants. Provided that many different simulations are run.
Religions have a traceable history, which shows they were entirely man made. No need to prove or disprove that this or that person talked to "angels" since angels don't exist to begin with.Therefore there is no truthful prophet.