If it is Group 2, possibility 1 (which does seem unlikely), I wonder what the filter is. Probably dinosaurs evolving into something completely different.
Reading that summary makes me feel like a pessimist. If you'd asked me 20 years ago I would have said the same as you (group 2, possibility 9). But I realize that my intuitions have started to shift towards a "Great Filter" possibility.
Advanced civilization seems hard and, additionally, trying to expand civilization off-planet seems like an obvious filter point (which would still be ahead of us).
Having thought about this never as long as just now, I'm gonna go with heebie, possibly because she is always right. Pizzaro/anthill.
The entire concept of physical colonization is a hilariously backward concept to a more advanced species.
This seems to me so completely obvious. I'm surprised that anyone would think a civilization capable of interstellar travel would not have also solved all the problems that lead to the desire to colonize new places. Exploration is a different matter, but colonization really requires a dissatisfaction with the home that's not likely to be there when all needs are being met.
What if their way of solving all their problems was to figure a way to get away from where they are now?
Also, given the way humans are behaving, it seems likely that a great many civilizations destroy themselves and end up regressing. The for a civilization to advance requires only the occasional smart individual capable of inventing something new and teaching it to others. For the civilization to survive requires coordinated effort among the majority of the members, and being just smart enough to pick up on the inventions of the super smart outliers does not guarantee being smart enough to cooperate in the face of global challenges like climate change or whatever the next big collective action problem turns out to be.
TL;DR right now but I assume they mention something not only about the # of planets and time for life to have evolved but the fact that it's probably a pretty small window in which that life is evolved enough for interstellar communication but doesn't blow itself up.
More specifically, it's also much easier for microbes to win the battle over multicellular life that cares about sending out spaceships or radio signals.
My favourite hypothesis doesn't seem to be there: higher civilisations are out there, but have no interest in trying to contact lower ones like us, because they have more rewarding stuff to do..
2-3, although I like Charles Stross's take on it in...Accelerando, maybe? Decreased time cycles, AI, and rapid software evolution means that these virtual paradises are full of titanic malicious intelligences that consume smaller human-brain-sized entities, especially those non-digitial-native (in the more literal sense) consciousnesses who just got uploaded. It gets us right back to the idea of The Ocean as a hella scary thing, an endless Abyss full of horrific monsters.
(Thinking about it some more, in his version, the underlying substrate of these entities was a self-modifying version of corporate law running on a Dyson sphere. Let's not let that happen.)
Group II, Possibility 3 is basically Infinite Fun Space from the Culture books, so I hope it's true.
I'll go with "The Great Filter is ahead of us" and agree with NickS. Of course it is possible you can become a Type II or III civilization and tend your own garden, but it seems incredibly unlikely that all such civilizations will do that.
The bit about the ants not understanding what's happening when they build the interstellar off-ramp highway through our neighborhood kind of ignores how the ants would notice a lot, right up to when the bulldozers crush their hill.
The preceding is my brain speaking; my heart wants them to be out there: the hurtling moons of Barsoom, Trantor, Ringworld, the Culture ...
12: Yeah, that'd be nice, too. It's also the hell space from The Culture books. I don't trust humans being in change of heavens, so we best make some gods first.
11: Charlie seems (possibly from story-telling contrarian reasons) to be pessimistic about space travel, but on the other hand writes about robots who are designed (by us!) to be humans in more resilient skins and bodies who are clearly up for exploring the galaxy. In "Neptune's Brood" I'm not even quite sure that they aren't literally human with modifications.
This would seem like a way past at least some Great Filters, though not all.
Yeah, I didn't actually quite agree with how 2.9 was phrased, and think it's closer to chris y's 10.
11: Oh, I hadn't thought about that story in years! That was a good one.
17: The only problem with 2.9, however phrased, is that it requires all super-advanced civilizations everywhere behave the same way. (The blog post calls it the 'non-exclusivity problem.')
None of them want to colonize, blow things up, make big lights and noises, take the Grand Tour of the universe? I suppose it's possible our TripAdvisor ratings are too low to warrant a visit: "Mostly harmless."
Actually, I don't understand the difference between 2.6 and 2.9. My loyalty is not that fine-tuned. I just think we're the dunces in the situation.
16: he does seem big on the idea of sending out embryos or gametes and growing little peoples there, as the life-support for an egg is a lot easier than a person. Reynolds explored that idea in Revelation Space with the Amerikano colonies, which always failed due to having too much crazy murder in their diet.
18: It was! I can't remember if it was the one where people could fork off (and then merge!) consciousnesses (or maybe even copies? Might be confusing it with Glasshouse, maybe?) but I really liked that era of his stuff.
None of them want to colonize, blow things up, make big lights and noises, take the Grand Tour of the universe? I suppose it's possible our TripAdvisor ratings are too low to warrant a visit: "Mostly harmless."
That's the same argument I've used to claim that no one will ever be able to travel backwards in time. Eventually, in all the future infinite time, someone would have messed with us by now. (The only logical conclusion is that if you travel backwards in time, you appear in the form of a hologram that only Sam can see or hear.)
How do we know someone hasn't messed with us?
Oh look, it's raining doughnuts.
There's an actual river flowing in the alley behind my office right now, but no doughnuts.
2.3, with the additional note that traveling between stars takes a very large amount of resources. (And it's entirely possible that we'll never solve the engineering problem of creating an artificial intelligence that weighs less than ten pounds and can survive being rapidly accelerated to .1c (and colliding with bits of interstellar hydrogen at .1c), thus no little smart space probes, either.)
A lot of these explanations don't seem mutually exclusive, so it might be promising to invoke several. E.g., maybe most advanced civilizations don't care to contact us; we are seeing the effects of some of their actions (as the ants do in DaveLMA's 13), but don't have the technology or understanding to realize these effects are the effects of intentional behavior (like the ants! sort of); we're missing the exceptional signals that are coming because we're listening in the wrong ways or unsophisticated ways or haven't been listening for long enough/far out enough into the galaxy; and so on. The strategy invokes more mechanisms, but seems to help with the non-exclusivity problem.
Right. The people in the world with the raining doughnuts didn't think of it as anything but rain. Which is why I think 23 is an important question.
29 to 26. Somebody from the future caused an error.
Re: 22, I like the the Larry Niven explanation, that any time anyone invents a time machine, they go back in time and monkey around with things, resulting in the timeline changing such that the machine is not invented after all. Our current timeline is the result of however many iterations of this it took to settle on something stable.
Interestingly, 32 doesn't preclude time travelers arriving from the future (since they could be from futures that have been overwritten by their own efforts); it just keeps you from ever discovering a time machine on your own.
I favor the one that says the aliens are already here, but not in an way we can understand, because that's what I think when I'm on hallucinogens.
18 is "Glasshouse" with maybe a side of Hannu Rajaniemi (and possibly even Swanwick's Station of the Tides, one of my favorite books).
The aliens are waiting for Naomi Watts to beg them to come visit. Don't they deserve it?
I know next to nothing about philosophy or physics.
I would have thought biology is the most relevant thing.
I favor the Zoo/Time Patrol hypotheses -- there are advanced species and time travellers, but they're deliberately hiding from us. Not so much because I think it's plausible, but it's the most fun. (Tied with the version of the Great Filter being in our future, where the Great Filter is the Singularity -- sometime not too much more advanced than we are now, civilizations hit some level of technological sophistication that means that they no longer bother having any tangible effect on the physical world. Or something like that.)
And 32 reminds me of Bester's "The Men Who Murdered Mohammad", which can be read here by non-practitioners of Halfordismo.
We are the aliens we've been waiting for.
I would have thought biology is the most relevant thing.
I don't even know enough physics/philosophy to recognize its uselessness.
We had the Fermi paradox thread before, starting somewhere around here. I remember the thread because I got so annoyed with some of you and wrote too many comments. I come down more or less on the side of "there isn't other intelligent life in the galaxy," with a pretty big amount of uncertainty attached.
They've obviously gotten to essear.
I'm with LB and all others anywhere on the spectrum between zoo / time cops / ants by the highway. I think they're there, I think they probably communicate in ways we don't recognize (knowing zero about the science, it seems silly to assume all species are going to use parts of the spectrum we're capable of monitoring but I also get we have to listen with the ears we have) and they probably don't do a lot of noticing us.
I like these because they leave the possibility of higher intelligences out there somewhere and they sorta-kinda could be framed as conforming to our own studies of the other lifeforms around us. Dr. Goodall may go spend years among the primates but only some of us even get the Far Side comics, much less study her work in detail and essentially zero of us go there and see them first-hand. If the aliens have noticed us and want to study us, they don't have to blanket the skies to do so and most of them would probably have no interest in us anyway beyond the level of crafting a meme GIF and referring to us when they insult one another.
Dangerously tangential, I kind of liked the surprise last issue of Planetary, in which someone builds a time machine and discovers the earliest one can visit with a time machine is the point in time at which the time machine was first powered on. Unable to go into the past, they find the room filled with older versions of themselves visiting and revisiting the earliest point available to them. It made for some good art, anyway.
Note: by "surprise last issue" I mean the final issue, the printing of which was a surprise to me since at the time I thought it had already been over for a year or two.
I got stuck in a time loop while policing a lesser civilization.
they find the room filled with older versions of themselves visiting and revisiting the earliest point available to them
There's a scene like that in Stanislaw Lem's comic novel The Star Diaries, but it doesn't involve a time machine, just a space-time anomaly.
"The Seventh Voyage", in which a spaceship defect forces Tichy through a series of time vortices, creating a multitude of temporal copies of himself.
If you consider that our existence is clearly biased by a selection effect--in looking at the Earth we're not exactly randomly sampling planets--and that it took us an order-one fraction of the habitable period of the Earth's existence to evolve (we're more than halfway through the total habitable interval, which has a fair amount of uncertainty attached but could run out 2 billion years from now), I think you have to conclude that our intuitions about the likelihood of life developing on a given planet are probably really biased. It's hard to know what an objective estimate would be, given the absence of data, but I suspect that life at or above the complexity of eukaryotes is probably extremely rare.
I also just want to note how terrified I am by the likelihood it's actually The Great Filter, yet to come, and we are just utterly boned. That is some seriously fraught does-our-species'-heart-weigh-more-than-the-feather-of-Maat shit and I'm pretty sure the answer is, oh buddy does it ever.
Weren't we all into Chariots of the Gods when we were kids? And of course all those bible stories are about aliens.
The meteor that killed the dinosaurs was a UFO, and we are the descendants.
53: The possibility that makes me most sad and somehow seems the most likely is a Great Filter double whammy. One Great Filter (or more), already past us, means that if our species' heart weighs more than the feather of Maat, that's it for ever and all time, probably -- and then another yet to come will demonstrate that yes, it does, and then that's it the end.
Weren't we all into Chariots of the Gods when we were kids? And of course all those bible stories are about aliens
I'm not taking this comment as serious, but it did help me realize that my particular kind of religious temperament--there are many kinds--probably accounts for my lack of interest in the topic.
44 it seems silly to assume all species are going to use parts of the spectrum we're capable of monitoring
Options are pretty limited if you want to send signals that don't get absorbed or rescattered into oblivion.
Let's say we assume there might be a Great Filter ahead of us; what's the best way to avoid it? My three suggestions in rough order of importance:
-Colonizing other planets
-Nuclear deproliferation
-Fighting climate change
I think there's a good utilitarian case to be made that avoiding a nuclear holocaust (or the rise of evil nanobots or sentient viruses or some other humanity-destroying disaster) is actually the only valuable goal.
Colonizing other planets
Because if we're worried that increasing the (small) CO2 content of Earth's atmosphere by 30% is having horribly destructive effects, surely the solution is to flee to somewhere where there's much less atmosphere and it's 96% CO2!
58.2: They might figure out something truly different for communication, like magic quantum entanglement embedded in Stross's teeny-tiny starships (from Accelerando).
But you're right: if you are using the electromagnetic spectrum there really aren't oodles of possibilities even if you are a Type II or higher civilization.
57: I hated Chariots of the Gods because he couldn't be bothered to get the history or the science even vaguely right.
Sorry, I'm being rude. But I never have a clue what people are actually imagining when they talk about "colonizing other planets". Which planets? How do you survive on them?
if you are using the electromagnetic spectrum
Not a very strong assumption, really. Pretty much any kind of stable matter takes a lot longer to move. Except neutrinos? You could try neutrinos. Hard to do without frying everything near your transmitter, and absurdly expensive in terms of the energy you would need.
The atmosphere isn't the point, the point is to spread out as much as possible so Kim Jong Il and his (Kim Jong) ilk can't eliminate the possibility of humans colonizing the galaxy by pressing a button. I know very little about what would make a planet a good place to colonize, or what technological advances we'd need to get there and survive. But whatever we need to do, we should get moving on it.
The atmosphere isn't the point
Actually, I rather like breathing.
But whatever we need to do, we should get moving on it.
Also, ponies.
62: It's like you don't even watch Star Trek. Class M planets, of course.
Obviously any signals broadcast by the aliens would be compressed and indistinguishable by us from noise, but most of their communications would be done by high-bandwidth wormholes.
I would totally comment on this thread but everything I would say has already been said more clearly and more forcefully by essear. So, uh, go essear!
Are you saying we have no hope of ever colonizing other planets, or are you saying it'll take a lot of work to get there, or what?
62: Mars is the obvious one, and one survives in self-contained sealed habitats which are presumably horribly boring. People have been thinking about this stuff for a long time, and the conceptual issues are pretty much worked out (especially if you ignore the stuff like terraforming). Self sufficient sealed habitats are close to being off the shelf technology, and since we're talking about million year timescales I think it's safe to assume we can close the final gaps. On those sorts of timescales terraforming might even not be batshit crazy.
If you're worried about nuclear war it'd probably be orders of magnitude easier to build a long-term bunker complex on Earth than some ricketty space colony.
How about we tell lonely, resentful young men that if they colonize another planet, they can be alpha males?
69: We barely have a presence in Antarctica, which has the major benefit of having an atmosphere we can actually breathe. "[A] lot of work to get there" doesn't even scratch the surface.
Space is big. No, bigger than that. Oh go buy the book already.
Of course, the smart thing to do is not colonize planets at all but rather to build big free floating space stations, but that's a whole 'nother level of difficulty.
Self sufficient sealed habitats are close to being off the shelf technology
Gee, it sure does sound exciting to go to Mars and live in a box! But why go all the way to Mars? I could try to do the same thing in the Arizona desert or something.
I mean, okay, sure, maybe if we really wanted to for some reason I can't fathom we could put a colony on Mars or the moon. Not really anywhere else. Great! What does that buy us? Reduce the probability of the human race going extinct in a given interval time by raising it to the power of the number of colonies? Seems unlikely, since any colony living in a sealed box is going to be a lot less safe in the long term than people on Earth.
Can you built a space station that isn't free floating? Asking for someone pedantic who isn't a figment of my imagination.
76: You seem to enjoy being gloomy. Are you sure you aren't really an economist?
Terraforming sounds like great technology to work on! Let's start by figuring out how we can produce a 30% drop in the CO2 content of Earth's atmosphere. That should be easy, right?
Well, there was a SF novel (I think it was supposed to be a trilogy but never got to book 3) where the planets were all tied together with twine. (Not actual twine but cyber nano awesome twine of some description).
66 Just make sure you scan for life forms first.
72 - Robert A. Heinlein, who was never wrong about anything* but especially not about the human condition and especially especially not about wimminfolk -- shows how well that will work in The Moon is a Harsh Mistress, in which a Botany Bay IN SPACE has no sexual violence and treats the little ladies with the deference due them in any given episode of The Virginian. So maybe the beta males wouldn't be interested.
* Just ask him!
So did they actually take down that cover of Space Oddity? I don't have the heart to go look.
Everything togolosh is saying makes sense.
We don't have a presence in Antarctica, but we also don't have any huge incentive to. It's not like it would be impossible to colonize Antarctica if doing so gave us a big boost in our odds of avoiding extinction. In fact, it'd take only a few billion dollars of government investment, right? A trillion at most.
Essear, you seem awfully cavalier about how amazing it would be to square the possibility of the human race's extinction or even raise it to the power of one plus epsilon.
Haven't yet read the thread but did anybody point out the big fallacy in the OP yet?
87: I've only read Starship Troopers. I figured that was enough to get the gist of the oeuvre.
Essear, you seem awfully cavalier about how amazing it would be to square the possibility of the human race's extinction or even raise it to the power of one plus epsilon.
Well, it's so exciting imagining a possible future where all the people on Earth are dead but a tiny hardy colony of survivors lives in a little box on Mars until eventually their fragile system with no access to new resources collapses and they die too. Obviously the second half of that scenario is the one to focus on improving, right?
90 cont'd: I haven't found it yet! I'll point it out later.
The OP seems too short to contain a fallacy. Unless you mean the linked post, which is too long to read.
Did I kill the thread? Sorry, thread. Hopefully some other threads are surviving somewhere in interstellar space.
What if little boxes on Mars turned out to be really super fun?
Didn't think about that, did you, smart guy?
What if little boxes on Mars turned out to be really super fun?
Reading Mary Roach's Packing For Mars permanently cured me of any desire I might ever have had to go to outer space.
We need to equip the boxes with detailed specs on all our technology so they can restart life on Earth once the nuclear dust is gone, like in Wall-E.
Tomorrow, Venus!
[Urge to say something thoroughly retrograde about the talented Ms. Watts repressed.]
Anyway, I thought we were all supposed to go to the moon to mine the Helium-3 and get RICH!
96 - I hear that Mars ain't no place to raise your kids.
Or abandoned shit would last for a very long time on Mars. That increases the chances that we'll be discovered after we're all dead.
Colonizing other planets is like tic tac toe.
I don't think abandoned shit would last all that long on Mars. It would get sand blasted to smithereens in mere millenia. For long term shit abandonment I'd suggest caves on the moon (protect from bombardment by space dust).
Well, the face the aliens carved on Mars didn't look recent.
Colonizing other planets is like tic tac toe.
Turns out my memory was remarkably faithful.
Everything you need to know about Venus is in this documentary.
106: But I don't remember that scene from WarGames at all.
I've been lurking for a while now and this seems like as good a time as any to pop in.
The Fermi Paradox has always struck me as a little odd, if only because almost all those answers are plausible, but even more importantly very few to none of the plausible ones are inconsistent with each other. They could all easily be true. It looks to me like the two most obvious answers involved are that it's making some huge assumptions about intelligence, and what that means, and that the likely filters that would exist aren't discrete developmental points so much as constant and very dangerous things that surround anything we would recognize as intelligence more or less indefinitely.
I think the first bit is probably the central problem with the paradox, though. We tend to instinctively think of 'Intelligence' as some sort of natural kind of thing independent of human beings, that we are better at then all the other living things on Earth. But this is mostly because it's satisfying to think that there's something like that. Intelligence in practice just means 'doing things the way human beings typically do'. We try to talk in terms of things like problem solving, but again what counts as a problem and what counts as a solution to it is equally bound of up the specific ways in which human beings go around doing things. When we say "What are the odds of intelligent life on other planets?" what we're really asking is just "Why aren't there strangely shaped and slightly odd human beings on other planets too?" Phrasing it the second way makes the paradox look a bit less paradoxical, though.
As far as filtering goes, we seem to already be in the process of filtering ourselves out very successfully. But even ignoring that, which is probably necessary for basic psychological health, it shouldn't be particularly surprising that things-we-think-of-as-intelligent-like-us wouldn't tend to last especially long. Tool making* is a massive, enormous, crazy evolutionary advantage and for as intelligent as we are we're still very much animals like all the other non-tool-making ones (and any other intelligent tool maker on another planet - tool makers have to come from somewhere) with one additional toy. That toy** happens to be, roughly, "the capacity to kill any other living thing or things on earth, and appropriate any and all ecological resources for our own in the process", and that's more or less the way we've gone about using it over the last however many thousands of years the species has been around. Even if we don't manage to kill ourselves off with climate change we're headed for any other number of extinction level catastrophes as a result, such as the fact that we're basically just eating everything around us. Just like with intelligence, "why don't we see more evidence of species out there that, early on in their development, gained the ability to kill (almost) everything in their ecosystems and consume all planetary resources?" feels less paradoxical to me.
And that's without even bringing in the incomprehensible vastness of space, and the incredible difficulties of doing anything off planet in practice, and so on. (Even the most realistic hard science fiction stories about people in space seem to have some point, deep down, where the ask you to assume something magical that is clearly not going to happen.)
* "Tool" also having the same feature of "intelligence".
** Spears-and-Bleach-and-Fire more or less covers these bases, so you don't need to get too far away from non-tool-making things to kill off everything around you.
Bummer of a delurk, dude. I'd find the fruit basket, but after that, it all seems pointless.
Welcome MHPH.
...as intelligent as we are we're still very much animals like all the other non-tool-making ones...
This is the key to what I was getting at in 7. Our rate of progress far outpaces any rate of change in our fundamental selves. Collectively we are idiots even though a few of us are smart enough to move the technological ball down the field for everyone, giving us greater and greater power and so potential to damage ourselves. Even those few who are smart enough to make an advance in one area may well be idiots in others. As a species we're just apes with nukes.
Would it even be responsible to help humans get off the planet? So that what, we can chew up bigger and bigger chunks of the galaxy? Someone write a science fiction story in which a peaceful species, millenia hence, turns out to worship Kim Il Jong for wiping us out just before the singularity.
As a species we're just apes with nukes
You ask me to help you?! Man is evil! Capable of nothing but destruction!!
Not that I'm sure that a peaceful life-form is even a possibility.
I think there's at least one Great Filter we've passed and at least one yet to come, though I don't find this depressing like redfoxtailshrub does.
96 What if little boxes on Mars turned out to be really super fun?
There's a green one and a pink one and a blue one and a yellow one and they're all made out of space-age whatsis and they all look just the same.
94: I did mean the link in the OP, in fact.
Of course, a Great Filter in our future doesn't necessarily mean the death of the species on Earth. It could just be that, e.g., transitioning from a Type I to Type II civilization is incredibly hard, and so is sending out useful self-replicating space probes, and by the time we are at all in any kind of position to possibly do either, we have other priorities about what to do with our available resources.
My feelings on this are best summed up by Alvie Singer's mother: "What is that your business?! You live in Brooklyn! Brooklyn is not expanding!"
You don't live in Brooklyn anymore.
117: I think I spotted the fallacy: they quoted Michio Kaku.
In the John Scalzi Old Man's War universe the humans are basically the worst among a generally pretty nasty bunch of species in a chaotic violent galaxy. The big debate among the various aliens is whether humans can be reformed or should they be exterminated.
We do that same debate every family reunion.
121: okay, there are at least two.
I'll bite. What's the fallacy you're looking for?
Anyhow the whole Great Filter thing assumes that intelligence is the natural and even inevitable result of continuing evolution, instead of a basically random outcome of a specific set of evolutionary pressures that have only occurred once on this planet, despite plenty of opportunity. So 1/100 seems like it could be quite dramatically too high for p(intelligence|life) in the Drake equation, and the Great Filter could just be the Great Unlikeliness, or whatever. Not like intelligence is in the top thousand or so successful adaptations on Earth, right?
How is that a fallacy? Wouldn't "The Great Unlikeliness" just be a particular type of Great Filter?
Human level intelligence and eukaryotic life both seem to have taken a long time to develop and are good filter candidates. I have no idea if it's possible to go from that all the way to "we are alone".
126: That is literally group 1, explanation 1.
128: maybe? I didn't read them discussing it that way -- more as an affirmative ending of evolutionary avenues by some externality -- but I could have misread, obviously.
128: That's a very charitable reading, but given the general tone of the whole article that doesn't seem like what they have in mind to me. (There's somewhere in the article where they say that stars much older than the Sun should host civilizations much more advanced than ours, which seems to beg the question in several different ways.)
Specifically: "There are far older stars with far older Earth-like planets, which should in theory mean far more advanced civilizations than our own." Unclear what "theory" they have in mind, short of some weird teleological view of evolution coupled with a complete lack of awareness of stellar evolution and its effect on habitable zones over time....
Fine work by essear in this one.
The sequel is "The Fermi Supremacy"
130: I... guess? The way they graphically explain it seems to represent evolution as proceeding ineluctably towards an end state of greater and greater intelligence until someone happens.
133: I think there's an assumption that if a civilization becomes advanced enough, it's going to monkey around with the local astronomical parameters to ensure it exists and thrives.
But of course, this is really just aspirational fan fiction.
133: I wouldn't read "in theory" to mean anything other than ceteris paribus there, which seems perfectly reasonable. If life on Earth has evolved in a similar manner at a similar rate to life on other planets, then we'd assume that on planets where the process got started earlier, intelligence arose earlier and would be more advanced.
It's not much of a theory, and the whole blogpost is devoted to talking about how, in practice, it doesn't seem to be the case, but the assumption that the way things have happened here is going to be roughly similar to how they have happened elsewhere seems like an obvious enough starting point not to need to be explained in casual writing.
Technology seems to progress mostly in a single direction, at least. Except when the fundies win.
133: Implicit is "if developing and retaining intelligent civilizations is at all a likely outcome of having an earth-like planet." The possibility that it is not likely is subsumed in the idea of a Great Filter in our past (or possibly our near future).
136.1: What, we just install a dimmer switch on the Sun?
If the sun gets too cold, we could add more hydrogen.
139: the post did not seem otherwise inclined to leave much implicit.
140: Well, consider in our case. How long do we have until this is a concern? Do you think we might manage to come up with something in that time? I mean, we're pretty dense but I'd like to think we'd have a fighting shot, give it the old college try. The dimmer idea is a little lacking, but perhaps we can workshop it a bit.
Why are we so worried about aliens destroying things when we should be focusing our attention on destroying our enemies on earth?
137: but that's crazy. It's assuming that things will have happened the same way they did here in one really hyper-specific way. It's like starting a conversation by saying "it seems reasonable to assume that any planet where life began would have eventually developed Appaloosas."
143.last: the easier alternative is to move the Earth. I know Archimedes thought he had that one figured out, but I'm skeptical.
146: "develops intelligent life in a few billion years or so" doesn't seem particularly hyper-specific to me, but even so, there's quite a few places out there. We really only need a handful to really take off to get a galactic hegemony and cantina bands and whatnot.
"develops intelligent life in a few billion years or so" doesn't seem particularly hyper-specific to me
Why not?
I mean, "develops eyes", sure. "Develops the ability to locomote indepdently", seems reasonable! Even "develops flight" seems more plausible than "develops intelligent life". That happened with all of one species over the three and a half billion year history of life on Earth, and that species -- while moderately successful for megafauna, and impressively good at wiping out other species -- is far from the most successful even among those that are currently living.
I was probably too generous to those other evolved traits. Anyhow!
By specific you mean unlikely? Yes, I think all those things are more likely; I can't imagine why you'd think they'd be in the slightest bit uncommon, so the "even" seems odd. They all happened multiple times. So I agree, there will probably be fewer intelligent species out there than there are flying, crawling, or seeing species. But there's lots of planets out there and lots of time.
I also admit that intelligent life is unlikely to develop twice on a given planet, but that's because, I assure you, if it looks like the dolphins or bonobos or mantis shrimp or clonal colonies of aspen are getting wise we'll cut them in their sleep. If anything, global thermonuclear war should increase the number of intelligent speciation events.
As for success: we've barely been around! Our species is, what, 100k years old? That's a short time to dominate a niche. Give us a little while.
(And we're not moderate successful at killing megafauna! We're fucking stupendous at it! Give us some credit! It's more like we retired while we were the reigning champ.)
150: the octopi and the corvids would like a word with you. Speciesist.
And we're not moderate successful at killing megafauna!
I meant that we're a moderately successful example of megafauna, who are impressively good at wiping out other species.
But there's lots of planets out there and lots of time.
Sure, I guess. But 1/100? That's absurd. If we started with 1/(the total number of species that have existed on the earth) then how does the Drake equation look?
154: they can contact me on their radios.
Sure, I guess. But 1/100? That's absurd. If we started with 1/(the total number of species that have existed on the earth) then how does the Drake equation look?
Doesn't this argument apply equally well to every adaptive evolution that only evolved once (or a few times) because it was really adaptive? Like, say, photosynthesis.
s/adaptive evolution/adaptation/
I'm pretty out of it today. And combative! Sorry. I blame dealing with credit bureaus.
157: probably not exactly, but none of those adaptive evolutions are germane to the question at hand.
157: Yes! Eukaryotes, multicellular life, photosynthesis, intelligence: these are all things we can only put an upper bound on the probability of because they happened once. I'm guessing they're all very very very... very unlikely.
Or, okay, maybe they are germane. I like being in a me-n-essear-against-the-world argument.
I'm of the opinion that the Great Filter just means that Type II and Type III aren't actually things that are feasible. Type III especially; I think the distances in space are so godawful vast that no amount of civilization is going to be able to get around that fundamental problem.
Totally unfair for the world, really.
I think whether we ever discover life there or not, Jupiter should be considered an enemy planet.
For that matter, we don't actually know how difficult it is to get RNA world or whatever in the first place. (My senior colleague is writing a new book which is supposed to be some kind of big secret. I read a draft and complained about a section that claimed that genetic material has been found in space, and it turned out the source was this, which doesn't seem to me like a compelling argument for the ubiquity of nucleic acids....)
Jupiter should be considered an enemy planet.
Jupiter??? More like Stupider!! Am I right????
(Also, as far as I can tell the process of writing the book consists only of cribbing from random googled news articles like that, Wikipedia entries, and conversations with people who are smart and/or famous. It must be nice to get paid gigantic amounts of money for that sort of thing.)
167: Suddenly I remember why we're supposed to go to Mars.
Actually, I think I heard that Jupiter is doing us a solid by keeping the asteroids in line.
The asteroids are our class brothers! Reject the false consciousness of Big Solar System!
160: Leaving aside just how smart octopi are, I don't think we know that photosynthesis has evolved just once. Maybe it evolved a couple of different ways and one was enough better that it out-competed the others before they could leave a fossil. Also, I don't see that you need photosynthesis per se. You just need a way for energy to get into the food chain. Two of those have evolved here (photo-and chemo-synthesis).
Suddenly I remember why we're supposed to go to Mars.
Something about switchgrass?
172: I probably should have said "oxygenic photosynthesis". And no, we don't know it, but I would bet on it.
As I said in the previous thread on this, you should all read Revolutions that Made the Earth by Lenton and Watson. They try to make the argument for why it's plausible that some of these things are very unlikely. We can't know for sure, but I think they make a persuasive case.
Two of those have evolved here (photo-and chemo-synthesis).
True, but we didn't have any really complex life on Earth until oxygenic photosynthesis completely changed the atmosphere. Energy can get into the food chain in different ways, but if you can't make use of the Sun I'm not sure you're going to get very far.
you should all read Revolutions that Made the Earth by Lenton and Watson
The Kindle edition of that book is impressively expensive. If only I had access to a library.
I think Arthur C. Clarke once said, "It has yet to be proven that intelligence has survival value."
Energy can get into the food chain in different ways, but if you can't make use of the Sun I'm not sure you're going to get very far.
Sure. My point was that if even a half-assed energy source like hydrothermal vents gets living organisms that exploit it, it would seem to indicate that evolving a way to take in energy from the environment isn't that rare.
"Intelligence" really isn't a sufficient condition for the kind of thing we're talking about. If a tuna were the smartest creature ever created, it still wouldn't be able to build a spaceship. Which is to say, you have to have intelligence, and the body for a particular kind of tool use, and to get that body, you have to have a particular kind of climate, fauna, predators, etc. It's a very, very specific thing to have evolved. Add to that that we don't have a very good idea about the origins of life. Interstellar dust and all that, but for all we know, there was something fortuitous about the dust landing here during one kind of global climate, and managing to stick around until a different one, when life really took off. Maybe that sequence is crucial, and again, the odds go way down, if so. This is a long way of saying that these numbers sure are pulled out of somebody's ass.
PSYCHIC SPACE TUNA, CAN YOU HEAR US?
Wow. I haven't had time to read the thread yet, but I love the linked post. Thanks!
What if there are supersmart plants that can't move because they are plants??
A bunch of thoughts.
I don't get why "the Great Filter being ahead of us" is so depressing. It could be something naturally wipes out technological civilizations, or it could be just as easily something naturally keeps them from leaving their solar system.
Glasshouse included another possibility: once you're advanced enough to ply the spaceways, you're advanced enough not to have to bother with solar systems: unless you're a hegemonizing swarm, there's lebensraum aplenty in the empty spaces between. Hell, maybe some of the dark matter is huge nonluminous civilizations far from stars.
Shouldn't working out of Drake's Equation generally exclude other galaxies? There could be enough individual small filters that large civilizations have sometimes developed, but only in other galaxies, and the void in between is yet another filter.
Wasn't it abundantly clear in Neptune's Brood that they weren't human, but collections of robotic cells that ran an improved model? Since the brains were on the human model, by some philosophies they could be called human, but not strictly speaking. I'd consider them worthy inheritors of our mantle, if that's anything to be proud of.
Stross has written some blog posts about his views on the fragility of extraterrestrial human existence, but I don't have links offhand.
136- Just build more solar panels.
I think getting chemical building blocks capable of storage and replication of information is pretty straightforward chemistry-wise. I think the big challenge for "intelligence" is still the don't get eaten by microbes problem. Microbes are made to turn everything into more of them.
Also, I don't see global warming as completely wiping out humanity, just resetting the numbers a few hundred years. Until you get to more Venus-like conditions, which won't happen unless there's some insane positive feedback loop, you still have enough arable and dry land plus farming technology to support millions of people, just not 7 billion.
Until you get to more Venus-like conditions, which won't happen unless there's some insane positive feedback loop,
Our methane caltherates, let me show you them.
Stross's thoughts minus handwavey technology: http://www.antipope.org/charlie/blog-static/2007/06/the_high_frontier_redux.html
Meh, even any potential release of those is only equivalent to a doubling or tripling of current CO2 levels. There just ain't enough carbon locked up to give you minimum global temperatures over 40C. The last two documented releases were responsible for big (96% of species) extinctions but I'm confident enough in our technology that we would still be able to maintain a few million people through such conditions.
The more likely scenario is arguments about who get to be those few million people and we settle the argument with a few hundred nukes.
I'm confident enough in our technology that we would still be able to maintain a few million people through such conditions.
Trouble is, employing such technology would be dependent on the non-breakdown of civilization. I don't see that happening once it becomes impossible to grow food outside a climate-controlled lab.
We're fantastically successful megafauna. Practically the only megafauna left is us and our food.
Yeah, I think once food supplies break down in industrialized countries we'll turn on each other like starving European peasants.
178 but for all we know, there was something fortuitous about the dust landing here during one kind of global climate, and managing to stick around until a different one
It's even more interesting than that: life dramatically altered the climate of the planet, and the atmosphere's composition, multiple times.
187 The last two documented releases were responsible for big (96% of species) extinctions
I was under the impression that there was a lot of controversy over the mechanism of most of the mass extinctions (aside from K-T or K-Pg or whatever it's supposed to be called now), but you sound authoritative. Is there really strong evidence in favor of the clathrate hypothesis for some of the extinctions now? (I guess you mean Permian/Triassic and... I don't know what the other one would be.)
194: And only once did somebody make any money out of it.
183 Hell, maybe some of the dark matter is huge nonluminous civilizations far from stars.
Awesome.
I like the parts of this that are about fun science fiction novels/stories and the ones that are about Halfordismo as the Great Filter, but essear's input probably still is the best bit.
Retinal and chlorophyll are independent, photosynthesis evolved at least twice.
With all the extremophiles it's hard for me to imagine life was ever in danger from complete extinction.
Huh, there are also multiple chlorophylls--all organisms with chlorophyll have chlorophyll a, but there are all chlorophylls b & c, whose presences varies on whether you're talking about plants, diatoms, various kinds of algae, etc. And there's a slug that can't produce chlorophyll, but can eat it and then use it! Neat!
I wish I could formalize my argument that there's way too much differently cool shit on earth for it to be improbable. (Yes, "differently cool shit" is strictly weaker than intelligence, but we were going that way anyway.)
My copy of the Lenton & Watson book is in my office so I can't look it up, but the photosynthesis thing is really interesting. They talk about how the two photosystems probably evolved independently and cyanobacteria happened to get both sets of genes through lateral gene transfer or whatever and were like "whoa! if I put these two things together, it's awesome!"
With all the extremophiles it's hard for me to imagine life was ever in danger from complete extinction.
That's what they said on Venus, before the climate went to shit.
Also, they claim that photosynthesis probably evolved multiple times and exists in various forms but that the step of splitting water to get oxygen evolved only once. Earlier forms of photosynthesis relied on less abundant electron donors than water, and so never really provided the big evolutionary lever arm that oxygenic photosynthesis did. I think that's their answer to 199. Plus, oxygenic photosynthesis gradually altered the atmosphere, and it's only after you get a large oxygen content that real evolutionary complexity and higher organisms develop, because oxygen is such a great fuel.
I'm definitely on team essear/Sifu on this. Strong work, team.
whoa! if I put these two things together, it's awesome!
You got electrons in my photosystem II! You got oxidizers in my photosystem I!
Meh, even any potential release of those is only equivalent to a doubling or tripling of current CO2 levels. There just ain't enough carbon locked up to give you minimum global temperatures over 40C.
Actually, now that I've thought about it, isn't the problem with the runaway effect not the CO2 levels, but the water vapor levels? Water vapor is even more of a greenhouse gas than CO2, and CO2 heating up the atmosphere means that a) a lot more water evaporates and b) the atmosphere can hold a lot more water vapor. So instead of a CO2 problem, its a CO2 + water vapor problem, which I believe is how you get from a mere 40C to Venus.
how you get from a mere 40C to Venus
One of the stranger entries in the Country/Western songbook.
PT and PETM extinctions, but that's just from wikipedia which says they're possibly linked so not authoritative at all although there are some links to actual journal articles.
And by links to journal articles I mean links from wikipedia, not that journal articles are linked to those extinction events.
210: well, wait, have we explored the latter possibility enough?
Only to actual journal articles. Pay to publish, non-reviewed papers have no possible connection to extinctions.
it's hard for me to imagine life was ever in danger from complete extinction.
I think this is a point environmentalists need to make more often, environmentalism isn't about "protecting the Earth." There's a 100% chance that no matter what we do the Earth will still be a big rock orbiting the sun for the next 10 billion years. There's a 99.9% chance that some form of life will continue to exist on that rock for many of those billions of years. There's a much lower chance that any carriers of your genetic material will be able to live on that rock for even a few million more years.
There's a much lower chance that any carriers of your genetic material will be able to live on that rock for even a few million more years.
The obvious solution to that problem is to implant some of your less mammalian genes into a the junk DNA portion of some very common bacteria.
If you mean masturbating into a used gym sock, I'm on it.
This seems like the thread to link this breaking news about an explosion in the Andromeda galaxy. See also #GRBm31 on Twitter. I don't have a very good sense of what can be learned from this, to be honest, but it seems exciting.
Clearly that's the Great Filter coming for us. We had a good run.
Isn't water vapor the ORIGINAL greenhouse gas? Maybe "orchid stench."
222 -- if you hadn't been dicking around on the internet, you could have helped us blow some shit up around here to compete with those Andromeda galaxy losers.
216 et seq: It's all seems great until you start running into flesh-eating bacteria that are also your cousins.
OT: Expired NyQuil is probably not a dangerous thing to take, right?
I'm still awake and coughing. Maybe it losses potency.
Damnit, why didn't I say "I've got you covered."?
Photosynthesis certainly appears to have evolved independently multiple times, for some vale of "independently".
Emotionally, I'm with essear on the question of space exploration. We've got machines to do that. Already they're pretty good at it and given the resources, they'll get better. Why (almost certainly) kill people to do it (almost certainly) worse?
Also, read this if you haven't. They came, they ignored us, they didn't take their garbage home with them.
While I'm personally in the "send me to Mars" camp, I'm totally with essear on the colonisation and evolution of intelligence points. On the former, what's the point, other than curiosity and technological/socio-cultural spin-offs? What problem does it solve that couldn't be more easily addressed on or near Earth?
On the latter, we have one example of an intelligent species even close to capable of exploring beyond the solar system, and if the sample had been taken a tiny, tiny fraction of the universe's existence ago (or quite possibly the same short distance in the future), we'd have none. We have absolutely no basis for assuming that there's a non-infinitessimal chance of such life evolving, let alone for assuming what its behavioral characteristics are.
Further to 222: apparently not, after all.
234. Not exciting, or not evidence of extraterrestrial intelligence?
I feel like all these options still phrase everything too much in our own terms. Its not just that we shouldn't assume that an advanced civilization would be interested in physical colonization. It that we shouldn't imagine that the processes that take place on other planets should be "civilizations" that "advance." I think we will be lucky to find something that we can clearly categorize as "life." And if it is "life" why should it be composed of "individuals" who have "consciousness."
I hate all the scare quotes, but they always pop up when you are trying to problematize every single one of your assumptions.
The idea that there is only one of something makes physicists itch uncontrollably.
They don't like how the parameters of our universe (things such as the ratio between the strength of the strong and weak nuclear forces) are hospitable to life. So, some hypothesize the idea that there are zillions of universes, each with different parameters, most of which are not hospitable to life.
I feel the same way about the various filters essear is talking about. Maybe the evolution of photosynthesis is really, really, unlikely. Maybe the evolution of intelligence is really, really unlikely. Etc. But it's almost hubristic to think these things have happened only once in the universe, or even in our galaxy.
The origin of life is just chemistry plus time, given a reasonably supportive environment: liquid water seems pretty essential. It's been said that the very earliest life forms seem to have appeared almost as soon as the Earth's surface was cool enough for them to survive.
If you look at our own evolution, it seems that there were several primate species that were pretty smart. Pre-humans developed the ability to make tools and use fire before their brains got big. There is a long-term argument about whether the apex predators have been getting smarter over time; I think the evidence is good that they have. If the asteroid hadn't hit, dinosaur descendants might have evolved high intelligence 50 or 60 million years ago.
There are a lot of reasons to believe we aren't unique, special snowflakes.
Arthur C. Clarke said "Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying."
(Clarke was absolutely the go-to guy for that sort of quote.)
we have a 6.5-σ threshold. Even then, we occasionally get false alarms.
Huhwhat?
Or is he just subtly bragging about the fact that they're making tens of millions of measurements a year?
But it's almost hubristic to think these things have happened only once in the universe, or even in our galaxy.
In the galaxy? There's a completely unknown probability that depends on multiplying a bunch of things and you think it's hubristic to think it might be 10^-x with x a smallish number?
238: systematics, not statistics, I think.
I feel the same way about the various filters essear is talking about. Maybe the evolution of photosynthesis is really, really, unlikely. Maybe the evolution of intelligence is really, really unlikely. Etc. But it's almost hubristic to think these things have happened only once in the universe, or even in our galaxy.
Well, sure, but there's a difference between thinking (or rather allowing the possibility) that it evolved more than once in the universe or galaxy, and thinking that it evolved more than once in sufficient temporal and spacial proximity for evidence of the one to be apparent to the other. Space is really big, the universe is really old, and we've only been broadcasting radio waves into space for, what, 100 years? And really weakly at that.
240: somebody likes being itchy!
I must have missed the part in the Bible that said we were the fourth stop on Christ's Saving Souls, Taking Names universal tour. We're it. The great filter is God's grace.
Note for future critical thinking courses: both the existence of God and the existence of extraterrestrial life are great places to illustrate burden-of-proof tennis.
If the asteroid hadn't hit, dinosaur descendants might have evolved high intelligence 50 or 60 million years ago.
If my aunt evolved wheels she'd be a wagon. Theropods have had however many brazilian years of evolution to work with and they still haven't done better than corvids, who are admittedly pretty smart, but who I guarantee I could out-argue on any topic more sophisticated than "no, I peck out your eyes".
My dad was a lot like Arthur C. Clarke, and about the same age. Same start in sci-fi, going into science, ever-broadening personal culture while remaining interested in the same mysteries.
I didn't really notice the resemblance until that half hour show that was syndicated on PBS in the 80s, where he would present some unexplained phenomenon and speculate about it.
Huh, there's another guy like that, I remember thinking.
Cambrian explosion to people in half a billion years. That's fast, all things considered--it could have taken a lot longer, and we'd still have time to be here and observe, uh, ourselves before stellar evolution makes us impossible. (Enh, this argument is looking scarily like those "the fact that you're born today means humanity will die out" arguments. Stupid anthropomorphic principle.)
I agree with 242.2; I don't think it's particularly likely we're going to run into anybody anytime soon.
246 cont'd: but the real problem is that there's no particularly good evidence that increasing intelligence is so all-fired important to evolutionary success. It turned to be the solution for one species of primate in one environment one time, but the cost (vastly more dangerous birth, vastly longer time before an individual is self-sufficient, vastly weaker muscles, enormous need for high-energy-density food) is huge. That we think it is obviously going to be worth all that for some species eventually is sheer anthrocentrism. Dinosaurs would have become intelligent? Well, maybe. But any number of dinosaur species were far more evolutionary successful over far greater timescales than humans have yet been able to manage, so maybe it wasn't actually very important for them.
A couple of additional remarks against the chain-of-miracles viewpoint:
Extremely specialized features which have evolved independently more than once is a long list-- eyes, metabolic adaptations to allow flight, intelligence (us, corvids, octopi, maybe more), ...
Like everyone else, I don't know the right parameter space for thinking about the likelihood of evolution of either unicellular life, or subsequent complexity. My version of musing about the distant past is to look at recent citations of good speculative papers about RNA-based life. There are lots of bad ones, I usually avoid speculative science reading.
For scale, any radio broadcast of human origin is indistinguishable from thermal noise from pluto, much less outside the solar system. The only way to send or receive a signal would be directed transmission, which has to be aimed somehow. That's a needle in a haystack rather than careful listening.
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Grand as those galactic explosions are, here on earth we just lost one of the world's most significant buildings
Crap. Reminds me of 2006, when 3 Sullivan churches burned down within 3 months.
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Theropods have had however many brazilian years of evolution to work with and they still haven't done better than corvids, who are admittedly pretty smart, but who I guarantee I could out-argue on any topic more sophisticated than "no, I peck out your eyes".
Yeah, but how good are you at attracting mates by blowing sound out of the enormous bony ridge on the top of your head?
NMM to the singer of "Miss Calpyso"
intelligence (us, corvids, octopi, maybe more)
But, again, not actually. They don't cook food, they don't have language (maybe they sort of have language, but they don't really have language in the way we think about it), they don't have anything remotely like the kind of social intelligence humans have, the kind of social intelligence that would lead to eventually thinking building a radio was a good idea. That kind of intelligence has evolved exactly once, and there's no particular reason to think that it would be evolutionarily successful in any of those other species, and plenty of reason to think it would not be.
I'm not saying they aren't smart -- corvids are amazing! Octopi are amazing! -- but it's a fallacy to think that because they're smart in interesting, comprehensible ways that something meaningfully akin to human intelligence has evolved multiple times.
252: I'm embarrassed to even try.
So there are around 10^11 stars in the galaxy, and we're here. That makes it not *too* implausible that the probability of something "us-like" for a given star is more than 10^-11 or 10^-12 (or is it; selection bias, again-- I could go by stars in the observable universe). It's of course smaller than 1 and smaller than 0.1 seems unlikely to lead to objections. Now, before putting in any other information, what should your prior be? I would say that flat on a log scale makes much more sense than flat in probability, which is why arguments like 237 seem hard to swallow for me.
And now my plane is about to leave... And there's a baby next to me.
242.2 "Space is really big," etc.
I don't disagree at all. I'm mostly pushing back against the idea that life is rare and intelligence is really rare and technology is super ultra mega rare. You seem on the verge of arguing that the final value of the equation is 1.
As for broadcasting, it's more about listening for intentional signals. Our broadcasts are pretty weak, as you point out, and haven't gotten far. I think they weaken enough that except for some huge DEW-line radars in the 50s and 60s, most would have faded into background by now.
The temporal proximity issue is really the biggie. That's more or less the last term in the Drake equation. How long does a species that has detectable technology last? Most species on Earth last a few million years, tops. Still, you'd think that if we get past our current crisis, we might last a reasonably long time. But overlap with other technological species might be small to non-existent.
Still, some fraction of technological species will likely produce self-replicating robot spacecraft, if only as a way of saying "We existed." Doing that is beyond our current abilities, but not insanely far beyond them. If that happened, evidence of other species' existence would potentially last a long, long time. (It's a pretty common SF trope, of course.)
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The workmen are listening to some mix that has thus far included "Come On, Eileen", "Hey Ya" and "Call Me". Must be an iPod? Or the hipster station? Weird.
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257.last: and he's already screaming in my ear. This is gonna be a long 7 hours.
261: if it's a little baby the drill is that they hate takeoff but then the plane motion conks them out. I hope for your sake that happens!
255. I agree that neither whales nor parrots can make tools or write, which limits returns from complex social interactions.
So yes, we are first to get this far. I don't have a refutation for the claim that it couldn't happen again, ever.
But I guess that I don't see a particularly effective brain as biologically more interesting than a particularly effective immune system. Feel free to differ.
essear, you monster, that baby is going to sleep for most of the flight. You could speed him on his path by offering to help the mom out in some small way.
You seem on the verge of arguing that the final value of the equation is 1.
Not at all. I wouldn't be surprised at all if there were lots of intelligent life somewhere out there. But I'm even less surprised that we haven't discovered evidence of it.
Still, some fraction of technological species will likely produce self-replicating robot spacecraft, if only as a way of saying "We existed." Doing that is beyond our current abilities, but not insanely far beyond them. If that happened, evidence of other species' existence would potentially last a long, long time. (It's a pretty common SF trope, of course.)
A long, long time, a long, long way away from our lightcone.
But I guess that I don't see a particularly effective brain as biologically more interesting than a particularly effective immune system. Feel free to differ.
Biologically interesting isn't part of the Fermi paradox. I don't think anybody here is making a strong argument against the existence of "interesting" life, just life that might reach out to us across the stars.
I don't have a refutation for the claim that it couldn't happen again, ever
That is certainly a much stronger claim than I intend! All I'm saying is that the only evidence we have is that it has happened once.
But I guess that I don't see a particularly effective brain as biologically more interesting than a particularly effective immune system.
On some level I agree with this, if only because it is definitely the case that maximal across-the-board immune system strength is not universally selected for; dogs, but not humans, can eat poop with relative impunity, although it seems clear that historically being able to eat poop would have saved people a lot of hassle. The ability to eat poop, which presumably incurs some cost, turned out to work for the niche in which dogs found themselves. The ability to (eventually) decide to build radios turned out to work for the niche in which humans found themselves. Intelligence, like poop-eating or having a weird blue hemipenis or looking like an Appaloosa, is an adaptation that occurred at least once on Earth. We don't know any more about its likeliness to recur on another planet with life than we know about any other adaptation that has occured on Earth. You could say "well, there are probably enough planets with life that anything adaptive on Earth will recur someplace" and, okay, but that's a much bigger denominator for that term in the Drake equation than any of the ones that usually get thrown around.
intelligence (us, corvids, octopi, maybe more)
I haven't seen anything to convince me that any corvid is more intelligent than Kanzi the bonobo (who is "us" to a first approximation), and Kanzi can't learn to make Oldowan tools (people have tried to teach him and he likes learning stuff).
It might be argued that bonobos can't make simple stone tools because their hands aren't formed to grip the stones right. And you could extend that argument to corvids and parrots and dolphins, etc. But in that case you have to conclude that the odds against a technological civilisation are probably the odds against intelligence times the odds against the evolution of certain very exact physical attributes in the same animal. Which makes the odds even greater.
Following up on 266.last, I think looking at the amount of time that dinosaurs were alive without developing radio telescopes (or self-replicating robots etc.) versus the amount of time that hominids have existed is instructive.
265. I thought that both essear and sifu were making exactly such claims about both the first oxygen-belching bacteria and the awesome dudes in the first scene of 2001, respectively.
For thinking about space, I reiterate that anything broadcast (rather than directed, like a radar array) will not reach pluto. Thinking about directed communication means that our neighborhood in space is extremely small.
offering to help the mom out in some small way
Seriously, dude. Offer a nipple already. You aren't using them.
re: 267.last
Yeah, although I find the claim that it's how the anatomy of bonobo hands that's the block profoundly implausible. It's the whole Django Reinhardt type thing, with humans.* You can be sure that if there was a human with some kind of hand disability that left them with the functionality of a bonobo, he or she would just rock on ahead and bash those stone tools out, no problem.
* although, on a purely nerdy guitar level, playing guitar with two fingers is a easier than people think.
Thanks to the band it's frustratingly difficult to google videos of a Bonobo playing a guitar.
re: 270
! I'm guessing as a parent you might have first hand experience of just how hard the wee fuckers go at those. Mine has occasionally reached out for me and grabbed, and I've damn near feinted.
I always get stopped on this conversation because I have no idea what odds mean when you only have one data point -- without much more information than we have (like, detailed information on a bunch of other planets where life did or didn't develop), I can't see how there's anything to talk about other than framing interesting questions for when we do have more information. Like, over the past few years we've certainly learned that the problem isn't that planets are uncommon, so that's something to work with, but not much.
265. I thought that both essear and sifu were making exactly such claims about both the first oxygen-belching bacteria and the awesome dudes in the first scene of 2001, respectively.
Well, essear argued that oxygenic photosynthesis was unlikely to evolve and hence complex eukaryotic life was probably "very rare", but that's not a strong claim about the existence of interesting life in more than one place in the universe, just another hurdle of probability before getting to human-like intelligence. I'm not sure exactly which claim of Sifu's you're referring to, other than that the evolution and (so far) success of human-like intelligence appears (like almost all evolution) to have been a function of the particular fitness landscape faced by African primates a few million years ago, rather than an inevitable feature of life plus time.
Theropods have had however many brazilian years of evolution
Must it always come back to the herpy stuff? Let's leave the chicken crotch grooming out of the aliens thread.
Count me on team "why do essear and sifu think we're such super-special snowflakes?"
In terms of self-replicating robot probes, I am not at all certain that we'll (or hypothetical non-self-destroying tool users) ever be able to make a robot probe that can continue to work for the 10,000 years it takes to travel between stars using non-magic propulsion. (Or that would be a combination of light enough and sturdy enough to be accelerated to near light speed by semi-magic propulsion (eg. starwisp) to make the trip faster).
Link for starwisp: http://en.wikipedia.org/wiki/Starwisp
Yes, I agree that it's difficult to estimate how likely tool use is. Possibly you all are right that we are unique snowflakes.
To 268, I would point out that there are many very unlikely adaptations which took a long time to appear-- flowering plants, a metabolism that sustains elevated and constant body temperature, ant adaptations allowing larger colonies, all of these showed up about 100M years ago, though life on land is ~400M years old.
Specialization takes a while. I see our specialization as one of many; possibly this is wrong. Older specializations have evolved more than once. I see the debate about the age of an adaptation as a debate about the rate of specialization.
N.B. I don't actually think tool use is the relevant aspect of human intelligence. It is necessary, but not unique and not sufficient to ending up at radio-builder.
what odds mean when you only have one data point
I do not agree with this. I see our specialization as a consequence of varied anatomy and a huge variety of nerve cell types. I think that it is possible to look at other specializations which are in a meaningful sense equivalently unlikely. Obviously, doing this is pretty speculative, so nobody responsible will publish in that direction.
But orchids and ants are both pretty fucking unlikely. It's solipsistic to focus only on the thing that makes us different. I need to bow out for now, though, sorry.
What would you see as the obstacle between tool-use and radio? Large-scale social cooperation?
We were covered with a molten scum of rock, bobbing on the surface like rats
Animals without backbones hid from each other, or fell down.
Count me on team "why do essear and sifu think we're such super-special snowflakes?"
Weirdly, I would characterize the contrary position this way. We aren't super special snowflakes! We have one adaptation that has served us reasonably well as a species for a little while and we blow its importance to life in general all out of proportion, despite empirical evidence that it is merely one among many, many adaptations that have led to success for a species, and not one of the most successful, by a mile.
Animals without backbones hid from each other, or fell down.
What does the Tea Party have to do with evolution?
282: social intelligence generally, yes.
not one of the most successful
What metric of 'success' are you using? I mean, I don't have a good one either, but I can think of a bunch of obvious metrics under which humans have had unusually, probably uniquely, large effects on the environment around them.
I can totally kick your ass at epistemic humility, Sifu.
Tom brings up another good category of explanation that does not come naturally to sf readers: the technology is not waiting in the wings. Energy won't get much cheaper, robotics won't get to the level of reliability needed, nobody gets the experience needed to bioengineer space-capable beings that are also stable in the long term, there are no feasible shortcuts to supertech through quantum physics or nanotechnology, etc.
287: a purely evolutionary one. Success propagating genetic material over time.
290 cont'd: but as far as environmental effects the atmosphere-transforming bacteria seem like they have us beat handily.
290: On that front, while we're not doing unusually well in terms of length of time in existence as a species (but of course, the game isn't over until we're extinct), we're (I think, I'm ballparking this offhand) doing freakishly well in terms of number of unique individuals in existence over the lifetime of the species for an animal roughly our size, which seems like a decent evolutionary metric.
292.last: yeah? I have no idea if that's true, but would have assumed some dinosaur species would have us beat there as well.
I dunno, what's a typical megafauna world population (in the absence of people)? Millions, at best, not billions?
Significantly late to this thread, still--
My favorite "solution" to the Fermi Paradox is Robert Brin's "The Crystal Spheres."
The shorter is that every star is pre-equipped with an invisible shield that can only be broken from the inside. Once a civilization gets the tech for interstellar travel, all it takes is ramming one space ship into the sphere and you're free (the hilarious part of this is that you don't know you're going to hit it. It's invisible.)
However, once you're out, you start finding all of these stars with no shields (meaning they've at one time harbored a space-faring civilization), but no aliens. Everyone is just gone. Those stars with shields still extant don't matter much--you can't get in.
So, we haven't seen any intelligent life because we're all basically imprisoned in stellar hamster balls. Anyway, here's the wikipedia link.
http://en.wikipedia.org/wiki/The_Crystal_Spheres
(Oh, there might be slight spoilers in that link, I guess.)
But orchids and ants are both pretty fucking unlikely. It's solipsistic to focus only on the thing that makes us different. I need to bow out for now, though, sorry.
Again, the Drake equation isn't about the likelihood of their being ants or orchids on other planets. If you want to come up with an lw equation based on speculation about the likelihood of evolving
eusociality and a segmented exoskeleton, go for it.
"their" s/b "there", obvs. That's like the second time in a week.
A few more insufficiently-examined assumptions:
1) I agree with 237, not 150 - there's no reason to think we're unique on Earth. If velociraptors had cars (with really long steering columns and really durable pedals, I guess) and everything else that we'd recognize as the results of an industrial civilization, we wouldn't expect to see any sign of it now, 65-plus million years later. The geological layers of fossil fuels would probably look differently depending on whether a civilization depleted them like we are, but maybe they went straight from steam power to solar panels. It could have happened before them, too, or between them and us, and we still might not expect to see any signs of it over this long timeframe.
2) Contra 138, technology doesn't progress in a single direction very reliably. The printing press was invented in China centuries before Germany, the ancient Greeks had all the principles of steam power figured out but nobody ever made anything that used it, etc. "The Road Not Taken" posits extreme path dependency: faster-than-light travel is easy to discover, but once a civilization finds it, they'll never make any other unrelated scientific advance. There might be a much better way to get to other planets that we haven't stumbled on yet.
3) 242 is a good point, and not only are we limited to what's broadcast, but isn't broadcast dying down as we use conventional radio less? Maybe that's one of the filters, transitioning from broadcasting to narrowcasting.
4) It seems to me that it makes a big difference how accurate our current understanding of physics is. If there's really no way around light speed, then getting from star to star is very, very hard. In theory it's possible, but it might not be worth the trouble. That might be the filter.
The first two make it less likely that civilizations like ours are out there. The third and fourth make it more likely that they're out there, but less likely that two of them would ever meet.
One Weird Trick To Make You Master of Your Ecosystem.
292: but of course, the game isn't over until we're extinct
I've burnt carbon all my life and I ain't dead yet.
If velociraptors had cars (with really long steering columns and really durable pedals, I guess) and everything else that we'd recognize as the results of an industrial civilization, we wouldn't expect to see any sign of it now, 65-plus million years later.
I'm not sure about the geology, but is this true? Our civilization, at any timescale where the relevant rocks are still around, would leave geologically peculiar patches of iron ore at least, wouldn't it? And an otherwise inexplicable mass extinction event.
Yeah, it sounds like total bullshit to me. There'd probably be direct fossil evidence (eg middens of cooked food, evidence of tool on bone). There'd be chemical traces (eg CO2 concentrations, semi-conductors and other rare metals), Velociraptor flags and lunar rovers on the moon, and so on. And that's leaving aside the possibility of artifacts being preserved.
244 is basically the plot of the Narnia books.
Pretty sure that if we can find dino eggs we would have found evidence of the dino Fords.
Pretty sure that if we can find dino eggs we would have found evidence of the dino Fords.
Didn't we have artist's impressions of that evidence linked in another thread just recently?
That was a GTI, you monster.
This was pretty interesting given the conversation up thread about dominant species. The only big animals that exceed us (or come close) in terms of population are rats and chickens, and they're both basically our food or living off of our food. Shit-ton of ants and bacteria and Antarctic krill, though.
re:292
we're (I think, I'm ballparking this offhand) doing freakishly well in terms of number of unique individuals in existence over the lifetime of the species for an animal roughly our size
This actually seems like part of the worry about filters, though. Our doing well as far as population (for megafauna) seems to be mostly a result of our remarkable capacity for killing everything around us (and also converting things into C02). Without that we'd be stuck in moderate to small populations, like other primates. Species that grow unchecked by other things often end up doing relatively poorly in the longer term, basically because of that initial spike.
(Also I suspect any number of dinosaurs would beat us here. There are way, way more of us right now, but a bunch of dinosaurs lasted a really,really long time with more moderate population sizes. And our current massive population numbers have only been around for, what, a thousand years maybe?)
I think the Trilobite wins the crown among non-bacteria for combo dominance at peak and length of career, basically the Kareem of species. Those fuckers lived for like 300 million years, totally dominated for huge chunks of that, and looked cool.
Are we counting species success there, or something much broader? (I'm asking suggestive questions because I really don't know the answers. How long did particular species of dinosaurs last, typically? "Dinosaurs", en masse, were around for a very long time, but that would be the same as giving us credit for "Mammals".)
In a past life, who amongst us was not a wily trilobite.
Humans, in a recognisably modern form, though, haven't been around that long. Couple of hundred thousand years, give or take, and for much of that period, we were hanging about in small groups in eastern and southern Africa. And, as per earlier comments above, our measurable impact beyond the confines of our atmosphere maybe dates back 100-120 years.
We're incredibly successful. We live everywhere, we eat everything. Think of an animal; some human somewhere is eating it. Given the environments people have lived with stone age technology we are unlikely to go extinct anytime soon.
Think of an animal; some human somewhere is eating it.
I'm really, really sorry. But I just thought of your cat. Do you think you should call home to check on it?
I can't see a dino industrial revolution being missed; maybe some stone arrowheads or something. Though my sense is that big parts of the fossil record are basically "this brightly colored scene features one guy whose elbow we found over here, and another guy whose toe we found thirty miles away who died about five million years later. Plus over there are a bunch of guys who fell into the same tar pit within two months of each other."
Admittedly, this is almost all ex recto. I'm not any kind of expert, so I could be completely off. I'm basing this mostly on SF and even shakier sources. But my understanding is that you really can't expect anything to last on a long enough time scale to be found by a new civilization of a new species and basically everything that has existed that lot is a statistical fluke.
There'd probably be direct fossil evidence (eg middens of cooked food, evidence of tool on bone).
Possible but not certain. Only a small fraction of remains get turned into fossils. More importantly, the geological processes that turn things into fossils or otherwise preserve them for a long time, like mudslides, are not conducive to long-term habitation. Places like Pompeii are rare. Not only that, but it's deteriorating further due to tourists and being exposed to the sun and rain. Will anything be left of it in five hundred years, let alone a million?
And an otherwise inexplicable mass extinction event.
There are a lot of mass extinctions in the fossil record. (Wikipedia lists five "major" ones, but says that the difference between major and minor is basically arbitrary.) I know a meteor is the suspect for the most recent one, but do they all line up with meteor encounters?
I don't have a glib answer to the thing about metal deposits or Fords, fair enough. Those would probably last a lot longer than bones. And these days everyone knows that plastic isn't biodegradable. But ten or a hundred thousand years is one thing. Are we sure they'd last tens of millions of years?
Not sure if all my disagreeing here is in the right spirit-- glasses will last for tens of millions of years unless heated, similarly artificial gems. Gold, platinmu, and Tungsten all have extremely low reactivity.
Here is a camouflage-patterned tungsten wedding band.
As far as how long some individual dinosaur species would have lasted it's hard to say (though that was what I meant), but plenty of them lasted a lot longer than we have and probably longer than we will. It's especially hard for me to say because it would take a lot of expertise in dinosaurs which I don't have. Wikipedia tells me that Hyaenodon managed a good 26 million years or so, though, which is pretty good.
I don't know if we have to assume that some hypothetical dinosaur civilization would have been based, technologically, around metalworking either (and that seems like the most durable option). A lot of what let us get started on that in the first place was the easily available abundance of fossil fuels, after all. You need a lot of heat to make things out of metal, or even just to make metal itself. Those fuels might not have been as easily available to them. But we can certainly imagine a moderately advanced species, technologically, that was built around specialized breeding of other species, or even genetic engineering. Or one that for the most part relied on wood or other materials less likely to have left obvious evidence millions of years later.
Glass can also wear down into little bits of sand or even smaller particles (and is likely to unless carefully preserved). Any glass objects during the cretaceous period would probably have ended up the way those bits of polished glass you see on beaches end up, and then eventually just disappeared entirely.
Dinosaur spaceships were made of MAN-LEATHER!
"But we can certainly imagine a moderately advanced species, technologically, that was built around specialized breeding of other species, or even genetic engineering."
Why yes, we can.
Those fuckers lived for like 300 million years, totally dominated for huge chunks of that, and looked cool.
Yeah, but did they have any cool mating displays? I judge all species by the quality of their mating display.
294: from Wikipedia--
for a while 95% of land vertebrates were Lystrosaurus.[12][13] This is the only time that a single species or genus of land animal dominated the Earth to such a degree.
Note that "a while" means at least several million years. Will we match that?
A population of 60 billion or so, eating vat-grown protein. It could happen! (In your face, Lystrosaurus!)
All available habitats filled with giant cityscapes, domestic animals strictly licensed due to limited protein availability, attack ships on fire off the shoulder of Orion, et cetera.
I want an actual dead animal for lunch, not vat-grown protein. Maybe cannibalism is a reasonable compromise.
Sure, vat-grown protein for the proles, proles for thee and me. I'm pretty sure John Rawls would approve.
266 We don't know any more about its likeliness to recur on another planet with life than we know about any other adaptation that has occured on Earth.
We know that many adaptations are one weird trick to make you survive in a very specific environment. No doubt a lot of human adaptations that distinguish us from other animals are like that. However, it seems really a stretch to argue that the tool-use/fire/big brain combo that turns you within an evolutionary eye-blink into a Stupendous Badass Top Predator is one of those.
As was mentioned earlier, humans live everywhere, eat everything*, etc. As adaptations go, ignoring minor and unforeseeable side effects like nuclear war, climate change, and so on, if you were some lowly scavenging creature it would be a thing that would work well in a lot of environments, #1 in the Grand Prix d'Evolution. That doesn't mean it's any more likely than any other adaptation to occur, but once it gets rolling it selects for itself much more strongly than poop-eating.
298: I think the idea of velociraptors driving cars is sufficiently cool that I want to believe in it, but I don't think any advanced species (except the Great Old Ones) lived here before us.
* If you add up the tonnage of land animals that are currently alive, humans and their food animals make up well over 50%.
Is there a likely way for humans to go extinct that wouldn't wipe out every other large land animal? What would the lystrosaurus survive that we couldn't?
Disease, maybe. Especially, some overly ambitious biological warfare.
287: we're not even close to cyanobacteria on any metric of environmental impact or long-term survival.
essear survived the babypocalypse!
331-332 - killer robots could do the trick, too.
New goal: kill all of the cyanobacteria and take their place.
Yes, if the killer robots could figure out how to stop running into the wall over and over again until they run out of batteries in an hour they could really do a number on us. Except that they would presumably kill all the large land animals/overstuffed armchairs/large balloons and street signs too what with the current state of computer vision. But I'm sure they'll keep at it and eventually everybody will take them very seriously.
Nice Robots kill people until someone takes them seriously.
338: but but but the Singularity is going to happen in a year or two and all that will instantly change!
298: 65-plus million years later.
A fair bit of discussion on that scenario in the thread on this general topic from last year (and also using 65 million years as a bogey starting from ajays's 382 in that thread). I'll stand by my assertion that a civilization similar to ours would certainly be recognizable to some degree by a 2nd such civilization 65 million years later, but the traces would certainly not be ubiquitous, and it would undoubtedly take some analysis and integration of geographically-dispersed data and observations.
I feel like people who believe in the Singularity have never actually used computers.
Probably remote sensing as well. Trying to do a back-of-the-envelope calculation of how much land "surface geology" area would be devoted to rocks from a 1000-year period 65 million years hence*. My first estimate would be at most a few tens of square miles across the whole globe (currently ~60M sqmi.land surface area. A disproportionate percentage of surface area at any given time is covered in very recent geologic deposits. But then there would probably be more clues in later secondary deposits--"unexpected" concentrations of metals and "erratic" rocks.
People who believe in the Siingularity have been used by computers.
People who believe in the Siingularity have been used by computers.
Perhaps even... bred to believe.
You just blew my mind, TJ. Now, how about my penis?
346: what are you some kind of nice guy?
People who believe in the Siingularity have been used by computers.
Some computers want to use you / some computers want to be used by you.