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Fantastic optimism!
In my younger days I had a soft spot for well crafted “space opera,” with David Brin’s “Uplift” series being an excellent exemplar. And yet the reality is that part of me always felt that these were more akin to space fantasy than science fiction. The reason is that a world such as the one you see in Star Trek, where aliens often meet each other at technological parity, just did not seem intuitively plausible to me. Rather, much more likely was the dark universe Gregory Benford outlines in Great Sky River. In this imaginging intelligent life forms meet across a chasm of technological sophistication which makes the idea of a broad class of organisms with the term “intelligent life form” laughable; humans were to the “higher intelligences” in this universe as ants are to us. Benford’s novel was depressing from a human perspective, and its coldly Malthusian universe reflects the pessimism of many biologists. I first encountered this in Jared Diamond’s The Third Chimpanzee, where the author suggests that optimism in regards to “First Contact” promoted by astronomers such as Carl Sagan in his work Cosmos was incredibly naive. Diamond’s basic contention was that if the universe was full of intelligent life forms, then we had better be glad that they weren’t here yet, because it probably wouldn’t end well for human beings, using our own planet’s encounters between different civilizations as models.
But I no longer even hold to the position that the cosmos is teeming with intelligences of varied levels of sophistication. Rather, I would guess that we humans are all there is in this galaxy.* I don’t speak of this often because I haven’t thought about this issue in great depth. And with these incredibly big picture inferences deduced from sparse data points one has to admit (at least I do!) that one’s confidence is just not high. What can a puny human truly grasp?
So why would I suggest that we are the only intelligence? Basically, the Fermi paradox. Rather that outlining my inchoate thoughts I’ll point you to Nathan Taylor’s posts at Praxtime, Life on Wet Planets, and Intelligent life is just getting started. With the appropriate caveat that we don’t really know much about this in any deep sense, it strikes me that major bottleneck for the emergence of intelligent life is the transition from simple unicellular life forms to multicellular organisms. Therefore the prediction from this model is that the universe is filled with life, but of the single celled kind. As Taylor lays out time almost ran out for the emergence of intelligent life on this planet (the sun is getting brighter, and it seems like that runaway greenhouse is inevitable ~1 billion years into the future).
Yet please note that we are likely just the first intelligent life form. If we go extinct soon before developing a form of automaton which can populate the galaxy there is plenty of time for other organisms similar to ourselves to emerge. The local universe is relatively young when measured in terms of the future existence of G (or K) class stars. That means the “responsibility” of being the first intelligent galactic species is somewhat attenuated on a cosmic scale.
Addendum: It is possible that the universe is teaming with intelligent non-technological life forms, and the upward ratchet of cultural complexity of Homo sapiens is a major bottleneck. I doubt that, therefore I have omitted a qualifier of technological intelligences, because I do think that if intelligences were numerous then many would have become technologically sophisticated.
* The whole space of possibilities is so much larger than our galaxy that I am somewhat wary of making broad assertions about the universe.
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A couple of my general objections:
1. Generalizing from Earth to any other planet suffers from an N = 1 problem. That something happened on Earth, and when, has limited implications for life elsewhere.
2. Venus may never have had water. Signs of it are disputable, and there is one paper positing that the planet formed from the collision of two equal sized planets.
3. The Fermi paradox invariably rests of the twin assumptions of perpetually expanding species and that such species would leave visible (to us) signs across the cosmos, neither of which can be taken as a given.
Ultimately only time will tell.
Fun to see Razib Khan link to me since I’m a many year gnxp reader. 🙂
One comment. When Razib Khan and I had our brief twitter exchange I pointed Razib to my post which focused on contingency of multicellular complex life, as I think that’s his angle of interest. So that’s the one he links to above. But in fact it’s my later one “Avoiding Carl Sagan Syndrome”, which is making the rounds right now (Daring Fireball, 3 Quarks, etc). It has a biologist (Theodosius Dobzhansky) versus astronomer (Sagan) framing which for example PZ Myer’s blog picks up on. That angle may be of interest to readers of gnxp if you want a bit more of a biologist’s take. In any case, enjoying seeing my name here. Keep up the good work!
Link to other my post
http://praxtime.com/2013/11/25/sagan-syndrome-pay-heed-to-biologists-about-et/
One issue I’d raise with the usual version of the Fermi Paradox – self-replicating probes spreading outwards – is that “colonization” might mean something different to machine intelligence than to us. A machine mind might find the idea of sitting in some solar system with many light-years time-lag between it and other people absurd, especially since it could just send back a digital copy of itself and all its data to “sync” with the version back home.
That changes interstellar exploration. A starship with resource gatherers and the fabrication equipment to build new starships might come into a solar system, explore it for many years while setting up the infrastructure to build new starships, cannibalize the infrastructure in the process rather than let it sit idle once it’s no longer useful, and then send back a digital copy of itself to the “home” system before moving on with little trace left in the solar system that it was ever there. There might be periodic “waves” of probes sweeping across the stars every few tens of millions of years, but machine intelligence would be mostly congregated in a handful of “nodes” where possibly trillions of them lived together in close contact. If we popped our head up in between visits, we’d have no idea that they had ever come unless we did a really thorough, on-site exploration of the entire solar system for remnants.
We have a couple of lineages that developed intelligence without sophisticated tool-using or development over millions of years, though. Chimps diverged from humans a few million years ago and are reasonably intelligent, but nothing came of it compared to us and the rest of the hominid apes.
I suspect the ability of a species to eventually build starships depends on not just intelligent life, but
1. Intelligent tool-using and recursive “use tools to make better tools” capabilities
2. Social organization
3. Capability for social organization beyond small groups of families or extended families, like nation-states or cities
4. Transmission of complex cultural ideas and beliefs.
Those don’t seem to be quite as common. If hitting all four of those targets has a probability on the order of 1 in 100 billion or so, there might not be any other civilizations in our galaxy – or they might be rare that they only periodically stop by every few hundred million years.
. . . . And of course, I do feel the obligation to point out that it’s not necessarily true that we might be able to practically build starships. It doesn’t even have to be impossible from an engineering perspective, just so incredibly difficult and reliant on a major space-based infrastructure that the nearest civilization that actually tried it just happens to be over in Andromeda Galaxy.
Consider across the muiltiverse all the civilizations at our level of tech that face a Fermi paradox. For some imagine that the true answer is that life is rare in their universe whereas for others the true answer is that life is common but some “great filter” gets civilizations such as ours before we can colonize the universe. If we are uncertain concerning our place in the multiverse shouldn’t we give high weight to being in the latter group because it probably has more members?
Furthermore, if the solution to the Fermi paradox is that civilizations such as ours collapse before they colonize the galaxy then observers such as us are common, especially given that civilizations will likely have the most members shortly before their collapse, in contrast under your theory we are special. And we become vastly more special if mankind goes on to colonize the universe because of the trillions upon trillions of people who will ever exist, only a minuscule fraction will be born on their species planet of origin.
@Sunbeam,
I’m not convinced the possible existence of AI precludes the possibility of expansion by biological entities.
@Brett,
“not necessarily true that we might be able to practically build starships”
My own speculation on this point is to notice the behaviour of bacteria on agar.
Continual expansion limited by resource exhaustion or poisoning by toxic by products.
If you gave a number from 1 to 10 for the level of technology required to dominate the planet and consume the easily available energy, and another to that required to send starships across interstellar space, you might assign 2 or 3 to the former and 10 to the latter.
It seems likely that uncommon foresight is required for development of new energy technologies to outstrip depletion at every step along the way.
The jump is never made because we inevitably become too resource poor to try well before we become technically able.
It is entirely possible that the answer to the Drake Equation is 1 and it’s really not that difficult to gets a low number like that with less optimistic assumptions.
That said, I think there are plenty of easy to imagine “filters”, as James Miller put it, that could explain the Fermi Paradox.
One that I mentioned in a reply to an earlier message on this blog is that intelligence may be an evolutionary dead end once it reaches the point at which it can break the biological imperative to reproduce. With the development of birth control, we have essentially made it possible to succumb to the reproductive compulsion to have sex without the reproductive consequences that long accompanied it. Across the developed world there is currently below-replacement reproduction with no clear mechanism to stop it once populations drop. Intelligence has essentially allowed us to short-circuit the behavior that compelled reproduction so that it no longer has to result in reproduction
It’s incredibly short sighted believe humans are likely the only intelligent life forms in the galaxy, which has 200-300 billion stars. I would put that belief right along side the belief long ago that the sun revolved around the earth, and that the earth was the center of the universe.
The speed of any matter can only approach the speed of light, never quite achieving it, and never exceeding it. So if that’s a physical fact of nature, no matter how advanced a species may become, that law of nature cannot be broken, and so most interstellar travel is impractical even if their lifespans were 10,000 years or if they had a colony ship that went through generations to reach another star. Even then, it would still be practical to travel only to the closest stars, and only near the center of the Galaxy where stars are much closer together and much more numerous. Those stars in the outer reaches of the galaxy, as is our sun, are pretty much unreachable being limited to some fraction of the speed of light.
Remember, all of the science fiction that includes interstellar travel solve the problem of not being able to exceed the speed of light with some science fiction technology – warp engines, folding space, worm holes, etc. But the speed of light may be a law of nature that cannot be broken, and that may be why humans have found no evidence of other intelligent life in the galaxy.
people seem to be under the misimpression that interstellar travel is going to be in the form of organic bodies. that’s kind of retarded. please follow the links if i provide them
http://en.wikipedia.org/wiki/Self-replicating_machine
I had a comment that got deleted on here, but oh well.
If you are going to invoke the argument in that wiki link for a possible workable mechanism for interstellar travel well and good.
But that also has implications that are a lot more immediate than the possible existence of other intelligences in the Universe. And to be honest, it sure seems like you can’t separate the possible existence of other intelligences from the implications of the technology described in that link.
I take it you don’t want to argue about Kurzweil in all his glory, and I can’t blame you it never gets anywhere. But it’s not going away, particularly if you use some of the other tricks in the toolkit. As nearly as I can tell, there really isn’t anything physically impossible about nanomachines, replicators, and the whole set of things that get talked about.
And they are very useful, as you invoking them shows. But they have other implications that can’t be ignored.
It doesn’t do any good to argue about the possible toll booth way up the road, when you have one right in front of you.
sunbeam, i let your comment through because i assumed i didn’t understand it because it was deep. i read it about 3 times, realized i couldn’t make sense of it, so deleted it. just an fyi.
Whatever, par for the course I guess. What I said was just a regurgitation of arguments I’ve seen and made reading “Singularity” threads.
Only problem is, that we don’t really know a whole lot about human intelligence, let alone artificial. That is just a total unknown. Asimov had a phrase in the short story The Last Question, “INSUFFICIENT DATA FOR MEANINGFUL ANSWER. ”
Just saying as a betting man we will build some aliens, a long, long time before we meet any that derived from any sort of biological evolution.
If we are around to do the meeting. If you like science fiction, I would suggest reading Iain Banks Culture books as I mentioned before. There are other books that deal with similar things, but this series at least tried to deal with some of the implications.
I do not think that we are the only intelligent life formed on this planet. Octopii and Cetacea for two in this go-round. And perhaps birds are the remnants of intelligence in dinosaurs. (perhaps the fore legs of T.Rex were for tool use)
What we are is an intelligence developed in a body that could provide limbs that could be adapted for tool use.
If we see life as flowing along gradients which minimize entropy for an isolated system, and intelligence one way to do this, then we should expect to see intelligent life quite often.
I’ve never understood why so many people find it so obvious that the presence of self-replicating machines would be something we’d readily detect at this tech level.
Why would they go around covering the surfaces of planets with megastructures, or be flying around in big craft? I’d expect them to be swimming in the sun, essentially impossible for us to detect at this point.
“it strikes me that major bottleneck for the emergence of intelligent life is the transition from simple unicellular life forms to multicellular organisms”
That’s happened many times on Earth, though. There are the three obvious examples (vascular plants, fungi, animals), but many others as well.
A greater bottleneck might be the evolution of freely mobile multicellular organisms (pretty much just eumetazoans, I think), or abiogenesis (just once on this planet, as far as we know).
I like Geoffrey Miller’s explanation for the Fermi Paradox: intelligent aliens just reside in their Matrix Pods playing video games all day.
Steve Sailer,
If our current understanding of physics is correct then there is a finite amount of free energy in the universe, so if you want to play video games for as long as possible you have to send out self-replicating probes to capture as much free energy as possible (which would mean killing us). Plus, you are basically saying you don’t believe in evolution because evolution would tend to favor life that wants to spread.
Thanks Razib for the nostalgic memories, I love David Brin’s books to this day, especially the Uplift serieis. Also love reading his thoughts and his commentary on his blog:
http://davidbrin.blogspot.com/2012/09/intelligence-uplift-and-our-place-in.html
One other thing I loved is that he pissed off Star Wars fans with his critique of the ideology behind Star Wars (he did one for Lord of the Rings for it’s elitiist views, but I don’t think I came across any angry reactions).
Since someone brought up The Matrix, there is of course the “simulation” hypothesis – that the Earth is actually a simulation within a computer at least a few hundred years more advanced technologically than our own. Simulating an individual living planet with an abiotic universe coarsely simulated surrounding it is far easier than simulating a fully dynamic, living universe.
Of course, the issue with this hypothesis is it would be nearly unprovable (though the “pixelated” nature of quantum phenomena is strangely suggestive), and that it verges on solipsism. Still, if it is as theoretically simple to create scores of simulated worlds a few centuries hence as has been suggested, statistically speaking we’re far more likely to be in a simulation than base reality.
Apparently, new fossils have pushed back the origin of multicellular (or, at least macroscopic – up to 17cm across), life to 2.1 billion years ago. This appearance was basically concurrent with the initial rise in atmospheric oxygen. The biota probably died out again as oxygen levels dropped to almost zero around 1.9 billion years ago as well, and didn’t begin rising again until 800 million years ago.
Whether there is any actual phylogenic link with the later Ediacaran biota will of course be impossible to determine. One wouldn’t expect to see much continuity over eons, and no one can decide what the Ediacaran biota (which is far more recent and well-known) is anyway. But it does suggest that at least in Earth’s history as soon as atmospheric Oxygen levels rose above a certain threshold complex life was likely, if not inevitable.
Taylor makes a lot good points. It has often seemed to me that this sort of speculation is more a form of Rorschach personality test on those who muse upon it, than an actual scientific mental task. Those of a conservative nature tend to lean more toward a relative lack of alien life, while those with a more “open” liberal personality give more credence to E.T. Personally, I’ve always been biased toward the “living universe” end of the spectrum, so a couple of thoughts along those lines to follow. I’ll preface this by saying have not thought about this issue in great depth either, but it’s a subject that makes armchair speculation entertaining and harmless.
Without a larger sample size it’s really impossible to say whether the 3.5 billion years it took to develop multi-cellular life is below or above-average. One can imagine conditions more stable and amenable to evolution than Earth likely was back then. There have been “snowball earth” scenarios postulated by geologists, who knows what other unique wrenches were thrown into the development of life at even earlier times?
What makes us think the Great Filter, if it exists, is more likely to be behind us, than ahead of us? Are we, as a civilization, really close at all (along the timeline of our existence as an intelligent species) to self replicating spacecraft, just because we can imagine it? I have my doubts. There’s no reason to think most other intelligent species would be any better than us at traveling through space by proxy or sending out clears signals across the galaxy (much less be as inclined to do so as we are, and close enough on top of that).
Also, there’s no reason to think that an alien probe would want to make itself seen to unknown intelligences (think of Greg Bear “Forge of God” consequences), or that it would stick around for any significant length of time. For all we know, Earth could have been charted many years ago by a probe who wrote home: nothing to see here. The idea that evidence would be likely to present itself in the few decades modern advanced civilization has been around, and in a format amenable to detection by our relatively primitive technology, seems myopic to me. Just beause the evidence may not be “everywhere” does not mean there was never any evidence. If an alien race sending out self replicating probes did not want their probes to eat the galaxy (which I think is likely, unless the aliens were unusually evil), the arrival of these probes would most likely be almost undetectable in the grand scheme of things and operating under some sort of Prime Directive.
Lastly, and most “out there”, it’s also not even clear to me that the apparent lack of evidence for ET upon which the Fermi Paradox is predicated is a strong leg to stand on. I have my doubts if such evidence were uncovered that it would necessarily become publicly available instead of yet another state secret. The upper echelons of human societies have kept such secrets of the stars from the masses as long as civilization has been around. I am doubtful that physical evidence of E.T. would be shared by our spook agencies any more than ancient stone-age priestronomers shared the basis of their knowledge of impending eclipses. Why would governments want to be bothered with the public rabble over such worldview-shattering revelations? Not to mention the upper hand that could be gleaned from the esoteric knowledge of an exotic civilization with exotic technology. I don’t necessarily think this is likely, per se, but I also do not think that every single UFO story out there is prima facie crazy, either.
I think it’s pretty unlikely that we’re the the first intelligent life in this galaxy. The math just doesn’t add up. I do think it’s plausible (though not likely) that we are the only current intelligent life in the galaxy. We’re a very long way from becoming a multi-planet let alone a multi-star species. Plenty of time to destroy ourselves or be destroyed by simple bad luck.