…and this is a 
A little pessimism about Extraterrestrial Intelligence
Category: Evolution • Science
Posted on: October 24, 2006 7:20 PM, by PZ Myers
Warren sent me link from The Indigestible, wondering if I was interested in these kinds of speculative questions about the existence of alien life. Why, yes I am...and even wrote something along the same lines a few years ago, coming to the same conclusions: I think intelligent extraterrestrials are unlikely.
My reasons are below the fold. Of course, I will retract my opinion immediately when Klaatu lands.
The Fermi Paradox is a conundrum proposed by pioneer physicist Enrico Fermi that questions the likelihood of Intelligent Extraterrestrial life. It begins with the Drake Equation or some derivative which guesstimates the possible number of intelligent civilizations in the universe, and then extrapolates expansion rates into the universe from a point location within the cosmos of that species or culture. The paradox concludes that there should have been enough ET's over the last 14 billion years that even if they moved at velocities achievable by human technology today, they could have swarmed over the galaxy, or even the cluster to which our galaxy belongs, many times over.
…
Remember, all it takes is a single space faring civilization to develop and survive. It would only have to happen once in all the history of the local group of galaxies and they should be here, or we should at least detect signs of them relatively nearby. So the question, naturally, is where are they? Where are the ruins? Even if they're not here on Earth right now in any obvious way, where is the interstellar traffic lights or radio chatter or giant interstellar construction projects, some of which would plausibly be grand enough for us to detect from our earthbound and space based observation platforms? Does this mean we, as intelligent beings, are unique or rare beyond imagination? Is it evidence for a Theistic Creator Entity or entities which created human specifically? Why or why not? How would you address the Fermi Paradox?
I think it's a non-problem and a non-paradox. The simplest explanation for the reason that ET isn't tapping on our shoulder is that the Fermi and Drake assumptions are wrong—the kind of technological intelligence that might build spaceships and radios and harness fire is very rare, and techno-species are spread very thinly over vast and uncrossable tracts of space.
I'm with Ernst Mayr on this one. Read the Planetary Society debate on SETI, in which he took the con side, while Carl Sagan argued for SETI. Mayr has a very dim view of SETI, as do I, and while I think Sagan was a clever man, I think he totally missed the point. There was also some amusing interdisciplinary physicist-bashing.
What Percentage of Planets on Which Life Has Originated Will Produce Intelligent Life?
Physicists, on the whole, will give a different answer to this question than biologists. Physicists still tend to think more deterministically than biologists. They tend to say, if life has originated somewhere, it will also develop intelligence in due time. The biologist, on the other hand, is impressed by the improbability of such a development.
But the gist of his argument is that we do have one fairly substantial body of evidence that illustrates the probability of intelligence evolving, and it's right here in the history of planet earth. We've got about a half-billion years worth of sophisticated multi-cellular animal life on the planet, and our kind of technological intelligence has appeared only once.
After the origin of life, that is, 3.8 billion years ago, life on Earth consisted for 2 billion years only of simple prokaryotes, cells without an organized nucleus. These bacteria and their relatives developed surely 50 to 100 different (some perhaps very different) lineages, but, in this enormously long time, none of them led to intelligence. Owing to an astonishing, unique event that is even today only partially explained, about 1,800 million years ago the first eukaryote originated, a creature with a well organized nucleus and the other characteristics of "higher" organisms. From the rich world of the protists (consisting of only a single cell) there eventually originated three groups of multicellular organisms: fungi, plants and animals. But none of the millions of species of fungi and plants was able to produce intelligence.
The animals (Metazoa) branched out in the Precambrian and Cambrian time periods to about 60 to 80 lineages (phyla). Only a single one of them, that of the chordates, led eventually to genuine intelligence. The chordates are an old and well diversified group, but only one of its numerous lineages, that of the vertebrates, eventually produced intelligence. Among the vertebrates, a whole series of groups evolved--types of fishes, amphibians, reptiles, birds and mammals. Again only a single lineage, that of the mammals, led to high intelligence. The mammals had a long evolutionary history which began in the Triassic Period, more than 200 million years ago, but only in the latter part of the Tertiary Period--that is, some 15 to 20 million years ago--did higher intelligence originate in one of the circa 24 orders of mammals.
The elaboration of the brain of the hominids began less than 3 million years ago, and that of the cortex of Homo sapiens occurred only about 300,000 years ago. Nothing demonstrates the improbability of the origin of high intelligence better than the millions of phyletic lineages that failed to achieve it.
In part, this is a probability argument: it is saying that the relevant parameter in the Drake Equation is very, very small, perhaps much smaller than the SETI devotees were plugging into it. Maybe, if we actually had accurate values for the equation, the expected number of spacefaring civilizations in our galaxy is something less than 1. The 'paradox' isn't.
But there's another, subtler lesson in there. What he's saying is that there doesn't seem to be any evidence for a predisposition to favor intelligence in biology. Features like multicellularity, photoreception, long sharp fangs, flight, etc., pop up in life's history over and over again, independently; but intelligence? Feh. The universe doesn't seem to like smart guys. We happened once, and what's more, we seem to be teetering at the end of one long chain of improbable events in the history of one marginal set of lineages, of which most of its members are in decline.
Carl Sagan didn't get this at all, and actually made a surprisingly foolish comment in his argument:
…it is better to be smart than to be stupid, and an overall trend toward intelligence can be perceived in the fossil record.
That's just wrong! He's done what Gould called "retrospective coronation", standing at the end of a long trajectory of evolutionary events and looking back, and assuming that his path was inevitable and favored. Life has gone in many directions, and intelligence is one of the least used paths. We selectively notice those rare species that show some hint of similarity with us, but honestly, the majority don't swing that way at all. If one looks at the history of the biota here without the usual self-important vanity, it's the bacteria that are the major success story, and the last big innovations that fueled an explosion of new, successful species were the flowering plants and grasses.
There are a couple of other reasons I'd throw out for thinking that extraterrestrial intelligence is not unusual for its absence.
Mortality. There's no reason to assume that intelligence confers longevity on a species…quite the contrary, being highly specialized may well make a species more fragile and sensitive to disturbance. Civilizations may be flickering in and out of existence before they have an opportunity to make themselves known. (Depressing as it may be, Homo sapiens will someday go extinct. Get used to that fact.)
Counterforces. One suggestion is that when a species reaches a certain level of intelligence, it passes a tipping point that drives it towards greater and greater specialization on intelligence. There could also be forces that oppose that trend. Once an intelligence has ensconced itself in a comfortable shell of civilization, there's no further incentive to be smarter, and there's even pressure to be less clever and fit in. Maybe civilizations reach that point where they invent TV, and then everything goes downhill.
Local opportunity. We really haven't reached the level of a spacefaring civilization, so we don't have any idea what it is like to have large numbers of people living off-planet. Maybe once you do reach the level of being able to live comfortably in space for long periods of time, there are new distractions that make haring off to some other star uninteresting. Those rare civilizations that leave their homeworlds may spend millions of years enchanted with and exploiting their local gas giants or asteroids or whatever.
Life can't cope with the Big Empty. We've evolved to live in the thin layer of slime on the surface of a planet with a particular kind of atmosphere, and we're used to thinking of our environment as relatively conducive to our existence. But the rest of the universe isn't like that, and the big message from space is that it doesn't like our kind. Being well adapted to thrive in a biologically rich environment may be what makes intelligence unsuited to thriving in a more sterile, dead environment. Space is for spores, not people.
Comments
"technological intelligence"
Technological being the keyword, I think.
Posted by: Numad | October 24, 2006 7:37 PM
"I'm sorry, but if you can't be bothered to take an interest in local affairs, that's your own lookout. Energize the demolition beam. I don't know. Apathetic bloody planet. I have no sympathy at all. "
-Adams
Posted by: Mike | October 24, 2006 7:38 PM
1) The Universe is a nasty, cold/hot, radioactive, and very, very dangerous place. The problems are not insuperable, but they are very severe, and intelligent species may find that exploration beyond their solar system just isn't a good use of their resources.
2) "Intelligence" as we currently define it, could be argued to be an evolutionary dead-end, and self-interest and self-awareness might lead inevitably to societal and species destruction from overpopulation, war, or other causes.
3) Other possible intelligent phylas on other planets and in other environments might use their intelligence in such different ways that we will not perceive them.
4) If another intelligence reached the technological level necessary for interstellar flight, they might evolve/translate/whatever themselves to a plane of existence not visible to ourselves. And, having taken that next step, they might have no interest whatsoever in looking back at a backward species which actually lives on the surface of a planet.
I am reminded of a remark made by Frederick Pohl to a group of UFO-nuts, "The problem is, you guys, that as science fiction writers and professional speculators, your flying saucers simply aren't weird enough to represent alien intelligence." (I have paraphrased, from memory.)
Posted by: H | October 24, 2006 7:54 PM
Evolution doesnt like smart entities?
A billion years ago (or whatever), the same could have been said for multi-celled organisms. There was a point in time where multi-celled organisms were extremely rare, and they could have looked at their ancestors and said "life doesnt like multi celled organisms"
I realize that single celled organisms are more common in absolute number even to this day, but it would be silly to look back from our vantage point today and say that life doesnt favor multicelled organisms.
I believe that the universe is still relatively young and that we are one of the first or earlier popups of self-aware, intelligent life. There is still plenty of hydrogen and usable energy to go around in the universe, and there are still many nebulae that are pumping out stars. There are still planets being formed, still black holes being developed, etc.
Maybe hmom sapiens themselves are the solution to the Fermi paradox.
Posted by: Aaron KinneyAaron Kinney | October 24, 2006 7:56 PM
How does Kurzweil's theory of the approaching "singularity" fit in with your supposition that homo sapiens will die out, or does it not fit in at all?
Posted by: Oxhead | October 24, 2006 7:56 PM
Wow, okay, so I guess this is your forté after all. ;) Thanks for the mention -- and it's funny that you bring up some of the other reasons I have for being a nonbeliever in extraterrestrial visitations, such as mortality (longevity of civilizations).
Eventually I want to go into that objection, and cover the implausibility of trans-stellar flight -- or at least its incredible impracticality. The reaction mass alone would be prohibitive ... Then, of course, there's the unlikelihood that LGMs could survive in our atmosphere, in our gravity...
Posted by: Warren | October 24, 2006 8:02 PM
PZ:
For what it's worth, Conway-Morris makes similar arguments that lead to similar conclusions. So does Hugh Ross. I realize that the latter thinks ours is the 'privileged planet', while you presumably hold that the confluence that led to intelligence such as ours is just one draw in the cosmic lottery.
Me? I don't have a stake in that discussion, as do those gentlemen, but it seems to me that nature is rampantly convergent and (given the brief nature of the hominid experiment) can we *really* be sure from the fragmentary fossil record that organisms just as intelligent as chimps or dolphins didn't prosper in the Mesozoic, and not just once, but many times?
If we can't be sure of that, in just one locale over just 600 my, how certain can we be if the improbability of such beings elsewhere, given the vast number of worlds, over a duration at least one order of magnitude greater than time since the Cambrian 'explosion'?
Respectfully submitted....SH
Posted by: Scott Hatfield | October 24, 2006 8:02 PM
Interesting speculations on both sides, but essentially meaningless at this point. All hypotheses are based on a sample size of *one*, and we have a whole lot more observing and growing to do. There could be great ruins of civilizations or technology out there that we can't detect. It may also be that our machines and technology will outpace our own evolution by orders of magnitude, expanding into space with much greater ease than we can. One thing is for sure: the likehood of finding an intelligence at our stage of development (100 year timeframe) has to be extremely rare. So I would say we are indeed alone, for all practical purposes.
Posted by: jeffw | October 24, 2006 8:02 PM
There's another problem here in the "physics bias."
Notice the statement "there should have been enough ET's over the last 14 billion years that even if they moved at velocities achievable by human technology today." Really? So we should be able to just up and send some folks to Alpha Centauri 6 or something, no problem? I mean, we've got the _physics_ down, so everything else is easy, physics being so much more difficult than everything else.
The "velocities acheivable by human technology today" winds up taking thousands of years. So who gets there? No one currently alive. Are we talking building "generation ships," with grand, self-contained ecosystems that can move between stars? How does one go about doing that?
The answer for now is, "one doesn't." No one has ever done it, and no one even knows how to do it. We don't even have proof of concept. Nor do we know how much it would cost.
Would some hypothetical ET civilization expend 20% of its Gross Planetary Product for 100 years(to pick a totally random number, no more likely to be wrong than any other) on a project that would never have any benefit to the home world?
We can't even get the nations of our world to expend 1% of its wealth to slow ongoing atmospheric changes that will result in a massive loss of land area from sea level rise in a time scale that is less than the putative star colonization. So maybe the ETs are no more likely to take the really long view than we are.
Posted by: James | October 24, 2006 8:02 PM
Ok, but what about the dolphins? Look, we all know they are as smart as we are (I read that somewhere.) so maybe like them the millions of other alien intelligences out there just don't like technology.
:P
Posted by: marsha | October 24, 2006 8:07 PM
Possibly related to this, depending on what-all you include in "intelligence": Blindsight, by Peter Watts. It's a swell book on its other merits, too.
Posted by: Trip the Space Parasite | October 24, 2006 8:09 PM
I agree but also wonder why people don't emphasise how rare scientific thinking in particular is. Unless your define science to be so broad as to be meaningless (as is the trend nowadays), it has only appeared twice: (arguably) in Greece and then in Europe (albeit directly connected to the earlier development). Cultures that haven't developed science can still develop a reasonable level of technology and medicine. A similar issue concerns the assumption that a culture would expand into space: there have been cultures that haven't been interested in expansion and discovery at all (China at one point) and the only real interest we've seen in exploring space was fleeting (although obviously we're constrained by our technology; but our technology may never win against our lack of interest).
Posted by: poke | October 24, 2006 8:12 PM
Jared Diamond made a similar argument in "The Third Chimpanzee", using woodpeckers as an example. He noted that the "woodpecker niche" (drilling into live wood for food and shelter) is an excellent place for a species to make a home in. However, only woodpeckers engage in this life-style. Convergent evolution that we see in so many other facets of life (everything from the eye to long ears that radiate heat) never produced anything else like a woodpecker.
From the book:
Even on remote landmasses that woodpeckers never reached, like Australia, New Guinea, New Zealand, nothing else has evolved to exploit the splendid opportunities made available y the woodpecker life-style. Some birds and mammals on those landmasses do excavate dead wood or bark, but they are only feeble excuses for woodpeckers, and none can excavate in live wood. If woodpeckers hadn't evolved in that one time in the Americas or Old World, a terrific niche would be flagrantly vacant over the whole Earth. - Jared Diamond
Now, I personally believe that there is, was, and will be other intelligent life out there. The universe is just too vast to contemplate otherwise. However, we may be the only woodpeckers in this region, waiting on the dead wood excavators to hurry up and get stronger neck muscles so they can join us for a meal.
It may be a long wait.
Posted by: prufrock | October 24, 2006 8:19 PM
Even granting that intelligent species tend to evolve once or twice in the course of a typical life-bearing planet's history, the notion that such species will often develop the kind of technical knowledge necessary to send signals into space and even travel in space seems questionable. We've run through quite a few civilizations in the course of our history, and it seems that very particular conditions are necessary to sustain a rich cultural tradition over long enough periods to develop sustainable agriculture, sophisticated metallurgy, writing, etc. Still more particular conditions are needed for these to be leveraged into a systematic exploitation of naturally available energy and materials to produce an industrial economy. Why should we assume intelligent species will eventually build computers, radios, space ships, etc.?
At the very outset, many intelligent social species might have great difficulty making the transition from small social groups to the large groups typical of agricultural civilizations. We have troubles of our own, when it comes to that. I'm sure a little thought would reveal many other turning points and barriers between intelligence and sophisticated, large-scale technological civilization.
Posted by: Bryson Brown | October 24, 2006 8:22 PM
I think jeffw is correct: a sample size of one doesn't tell us much.
I think the parameter on the Drake equation representing the civilization's lifetime is an issue: the span of time from "begins using electromagnetic communication" to "optimizes use of the electromagnetic spectrum" (which means not wasting energy on the rest of the cosmos) is probably a couple of centuries, and if they aren't leaking for SETI to see, SETI won't see anything.
Posted by: Max Kaehn | October 24, 2006 8:35 PM
I estimate that ...
1) Humans as they are, are not smart enough to survive. We COULD conceivably be extinct in as little as a hundred years.
2) We're not really separable from our environment. Our environment is not just our life support, it's our LIFE. We can't live without it, and it's far too complex to recreate in a working model. The minimum necessary life support system for human life is the size of a planet. The only way to travel through space for any distance is on a planet orbiting a sun.
As to that second one, it seems to me, all things considered, that we might as well talk about your thumb going on a three-week vacation to Europe while the rest of you stays here in the U.S., as to talk about sending live humans off in a can into deep space. Space is an uncrossable desert, and separation from Earth is death.
Posted by: Hank | October 24, 2006 8:36 PM
I think PZ has it here: "Maybe civilizations reach that point where they invent TV, and then everything goes downhill." Evolution probably favors the discovery of TV before space travel, and no one gets much further than the closest moon. All around the universe are civilizations of people watching the equivalent of Fox News. No wonder no one is going anywhere...
Posted by: oldhippie | October 24, 2006 8:36 PM
PZ, it doesn't alter the force of the argument, but I'm kind of surprized you didn't take exception to this little snippet:
The animals (Metazoa) branched out in the Precambrian and Cambrian time periods to about 60 to 80 lineages (phyla). Only a single one of them, that of the chordates, led eventually to genuine intelligence. The chordates are an old and well diversified group, but only one of its numerous lineages, that of the vertebrates, eventually produced intelligence.
Especially given such recent evidence as this.
Posted by: Kurt | October 24, 2006 8:56 PM
It should be pointed out that a necessary (but not sufficient) condition for intelligence is a large brain. There appears to be a selection advantage for brain size to increase because it is my understanding that the Cretaceous dinosaurs had larger brains relative to their size then did their Jurassic antecedents and the mammals of today have larger brains relative to their size then did the mammals of 50 million years ago.
Posted by: SLC | October 24, 2006 9:06 PM
There's always this possibility.
Posted by: Mena | October 24, 2006 9:26 PM
Two points:
It could be that our current state is fleeting, and that most civilizations progress rapidly beyond it. This 'something' is probably not recognizable by efforts such as SETI.
It is much more entertaining to believe that millions of space trekkers have sprung up over billions of years. If this were the case, the odds would be high that one or more of them would be aggressive to the point of wanting to exterminate all other races. If this happened billions of years ago, they would have already destroyed everything except themselves, at which point they'd hunker down and wait for nascent civilization naively blast radio waves into the ether.
They're probably on their way even now.
Posted by: carlosmorales | October 24, 2006 9:46 PM
My two cents, skipping over most other people's comments:
I imagine that the sheer scale of the universe means that there's likely intelligent life out there. The problem is that it's probably spread out extra-extra-thin for many of the reasons mentioned.
And if intelligent aliens do exist, I doubt they're like the humans in 4+ hours of makeup we see on Star Trek. :)
Posted by: Bronze Dog | October 24, 2006 9:58 PM
Aww, c'mon, if you watch enough bad alien invasion movies then really PZ's point is optimism, not pessimism. Who wants to be blown up, replaced by duplicates, brainwashed, had eggs laid in them, or enslaved by alien overlords? ;)
Posted by: Diego | October 24, 2006 10:02 PM
If one looks at the history of the biota here without the usual self-important vanity, it's the bacteria that are the major success story, and the last big innovations that fueled an explosion of new, successful species were the flowering plants and grasses.
Word.
I remember when that toxic dweeb Professor Alschuler from University of Chicago was peddling intelligent design and he began an argument with, "If we set aside microbes ..."
Just another clueless "conservative" retard.
Posted by: Great White Wonder | October 24, 2006 10:10 PM
"...it is better to be smart than to be stupid, and an overall trend toward intelligence can be perceived in the fossil record."
Sounds like something Sagan said while stoned. And strange, given his frequent admonishments for humans to be humble. Sagan, of course, was also quite worried about the longevity of the human species, even while not high.
carlosmorales: "It could be that our current state is fleeting, and that most civilizations progress rapidly beyond it. This 'something' is probably not recognizable by efforts such as SETI."
Right. For now, all we can think of is radio. But maybe by the end of the century -- an eyeblink for a civilization -- we'll be using, I dunno, Schmendrick Waves. Or, we'll discover ways of harnessing our own solar system, obviating the need to colonize other stars.
The other, more frightening resolution to the Fermi Paradox is that there's at least one interstellar intelligence which snuffs out whatever civilizations it detects before we get a chance to hear them. Or, in a more friendly interpretation, they roam around teaching planets how to use Schmendrick Waves.
Posted by: Grumpy | October 24, 2006 10:13 PM
Marsha:
I mention cetaceans and cephalopods as being intelligence-bearing orders/classes, actually; I draw an added distinction with toolmaking, though, because while it's possible, maybe even probable, that bottlenosed dolphins have language, it doesn't do us much good in the sense that an ET intelligence like dolphins would be completely unkown and unkowable to us, probably forever.
The kind of engineering-fetish brains we have is -- I'm pretty sure -- so rare that the idea of ET intellligence is basically a profession of faith.
The point of the post is to begin to lay groundwork for an argument against the entire idea of "flying saucers" -- not by debunking sad, blurry photographs of random blimp lights, but instead by attacking the foundations of the mythology; i.e., why intelligence (as we would perceive it in high-tech species) is probably vanishingly rare; how improbable it is that a true spacefaring race would come by and "tease" us a la Douglas Adams by tormenting rubes in BFE; and how unlikely it is that we could have some kind of ET visitation and not detect the mothership in orbit -- which would have to be absolutely huge to set out on an interstellar voyage.
It all dovetails, and the picture it paints is one of a universe that may indeed be inhabited by intelligence -- but isolated from each other by vast gulfs of space and time.
Bronze Dog has it right, too -- the idea that ET life would be bipedal, bilaterally symmetrical, and basically humanoid is simply absurd.
Posted by: Warren | October 24, 2006 10:18 PM
Some perspective on perspective
I certainly never saw myself ever writing one of those shrug-of-the-shoulders kind of responses to a scientific question that are far too common in mainstream media articles, say about evolution, saying "we just don't know enough, yet - who knows, maybe?" But as an astronomy teacher in today's day and age, when you pile so many unknowns on top of prepositions on top of wide estimates, you have to step back a little to get some perspective on our "perspective." If you're really looking at the likelihood of intelligent life on other planets, you can't ignore the enormous revolution going on in the science right now.
Astronomy is changing so quickly and dramatically, there is cause to be skeptical of any current analysis of just about anything involving too much speculation and celestial odds-making like we find in the Drake Equation.
For instance, using new technology that has been developed over the past decade, we've found planets around pulsars, something seemingly impossible before the conclusive evidence shocked the world into a new paradigm.
The other hundreds of larger planets discovered around other stars also have completely torn apart planetary formation and migration theories in the past few years to the point where the science has barely had a time to catch its breath. And we haven't even begun to detect what are sure to be even more plentiful smaller terrestrial planets.
We haven't done even the most rudimentary search for extraterrestrial life in our own solar system, let alone on the myriad of worlds that we know surround us from all sides in unknown but probably staggering quantities from the depths of the cosmos.
Evolution has shown us the magnitude of its power over time to adapt to just about anything thrown its way. Life may or may not need water and it certainly needs energy to survive, but its most powerful fuel is time. And that IS one trait the earth shares with its celestial cousins - the seemingly countless eons silently ticking away, each one giving new life a chance to take hold, evolve, and die simultaneously on what seems like an infinite number of worlds.
When it comes to these matters, we know so little. We must keep searching, listening, looking. The universe is surprising us at every turn.
Posted by: Avian | October 24, 2006 10:18 PM
There's another possibility, of which PZ must be aware (it was mentioned in James Cameron's Aliens of the Deep): that complex life, even intelligence, is far more likely to evolve on hydrospheres like Europa. Being aquatic, such beings would be indifferent to the topside of the ice, and would never see stars. (Though imagine the Magellanic voyage of such a being who dared to penetrate the surface!)
Posted by: Grumpy | October 24, 2006 10:19 PM
If humans vanished tomorrow, how long into the future would human artifacts last?
What would be likely to last the longest? (Maybe some of the geostationary satellites??)
Posted by: Arun | October 24, 2006 10:41 PM
We cannot adequately define what we mean by "intelligent", so we cannot begin to determine how likely intelligence is, nor how likely such intelligence is to produce communications technology that we are capable of detecting.
We cannot even ask the question coherently, and you want to provide an answer? A better question is whether intelligence is likely to ever arise on this planet - let the others be.
Posted by: Caledonian | October 24, 2006 10:44 PM
Quick question: Has anyone here read Stephen Baxter's "Manifold Trilogy"?
I'm just curious.
Posted by: Jacob | October 24, 2006 10:46 PM
As a Geek, you will be Raptured, and your Quantum Cybernetic Brain will far too intelligent to be concerned with such mundane trivia.
:-)
How does Kepler's extended discussion of crystal spheres fit into modern astronomy?
How could Kepler and Brahe and so forth have known what would be thought of their ideas much later?
Posted by: llewelly | October 24, 2006 10:58 PM
You know, I get the feeling intelligent life is inferior to microbial life. You can find microbes almost anywhere--hundreds of feet below ground, in thermal vents, Apollo space capsules--and here we are, huddled together in a few temperate zones drifting on glorified islands, looking up at the stars with parasite ridden eyes and wondering why nobody else bothered with our way of life.
Posted by: Baratos | October 24, 2006 11:08 PM
I don't think so. Based on evolutionary history, I think there is a weak advantage to intelligence. Brains take a lot of energy, so they'd better be bringing a species a decently large advantage otherwise they're not worth the cost. I also think that maybe a good brain is simply a hard thing to evolve; there might be a very narrow pathway (in terms of mutations) to evolving a good brain. Because of the brain's cost, you probably need a relatively active body that can gather enough food to feed it. This might require a warm-blooded animal (as opposed to some reptiles who can go for a month without eating). Also, I agree with Sagan that there seems to be an upward trend in brain sizes (obviously there are counterexamples, for example, with bats). If you mapped out brain sizes of organisms over the past 600 million years, I think you'd wind up with the largest brains clustered towards modern times. Dolphins, whales, pigs, elephants, dogs, wolves, humans, apes all have brains larger than any of the dinosaurs. I'm not saying there's a strong advantage to big brains, I'm just saying that the increases in brain size over the past 600 million years says that there must be some weak advantage to it (or, alternatively, a big brain does have a big advantage, but the construction of a good brain is difficult to do well in terms of neuron growth, nourishment, balancing neurotransmitters, etc that it rarely ever happens).
Posted by: BC | October 24, 2006 11:12 PM
I, for one, Welcome our new, one-neuron parasite overlords.
Posted by: llewelly | October 24, 2006 11:58 PM
How does Kurzweil's theory of the approaching "singularity" fit in with your supposition that homo sapiens will die out, or does it not fit in at all?
I remember right, Kurweil thinks that man and machine will merge in a symbiotic relationship. Over a longer stretch of time, I would view it more as a catalysis, the end result being the emergence of forms of life that this planet has never seen before.
You could call almost any significant transformation a singularity, depending on the time scale under consideration. Abiogenesis, the cambrian explosion, and the industrial revolution are all singularities. Viewed from the distant future, the industrial revolution plus the next few hundred or thousand years might be a singularity.
Posted by: jeffw | October 25, 2006 12:03 AM
Caledonian:
I think "intelligence" can be defined -- for my purposes anyway -- as "able to produce communications technology that we are capable of detecting."
;)
That's glib but there's a serious side to it as well. While I know that our understanding of the universe might very well be myopic, so much so that future generations will laugh at the hubris we had in asserting lightspeed was the max velocity attainable by matter, I don't think there's anything like sufficient evidence extant to suggest that we're going to find an escape hatch or shortcut from relatavistic limits.
That means that I can't readily imagine a communications medium that doesn't involve some kind of radio transmission.
But even if there is such technology -- gravity-based, perhaps? -- it would still have to be physical, which means it would have to be physically detectable, and we'd find it.
How can I be so certain? Because information is not noise; we would detect any apparently nonrandom event going on in the heavens, we'd be riveted by it, and once we understood we were looking at a signal, we'd study it and attempt to replicate it. I'm pretty sure of that.
We would also be able to tell the difference between signal and noise, which is why we know what pulsars are (more or less) and aren't wowed by them as we once were when their output was first detected.
Put another way, there are obviously nontechnological intelligences. I named several in my post on TI. However, for the purposes of discussion of ET contact -- which I'm taking on a bit at a time -- nontechnological intelligence is irrelevant, because from the standpoint of detection and contact they might as well not exist.
Which, if you think about it, is rather sad.
As to intelligence being favored -- it could well be a sexually-selected trait. That might explain why our brains seem so disproportionately overengineered for the relatively simple tasks that most primates undertake daily to survive.
This would lead to an interesting recursion, with intelligence internally selecting for intelligence rather than the more conventional "outside" pressures of survival and propagation being the exclusive selective forces.
That, or when the First Primate was touched by His Noodly Appendage, the primate's brain behaved like the Grinch's heart and suddenly grew three sizes that day.
Or maybe Clarke and Kubrick (and, come to think of it, Brin) had it right.
But I think I'll stick to the more plausible sex selection/FSM hypothesis for now.
BTW, Baratos, your comment on microbial life was clever. I liked the perspective.
Posted by: Warren | October 25, 2006 12:21 AM
Even if there were intelligent life within a reasonable distance, there's always the possibility of 'beaming radio at savages'. Besides advances in compression and the like, which is eventually going to make our planet effectively "silent" (or at least, hidden amongst all the static), it's entirely possible that there's a more reliable form of communication to be had that relies on quantum effects. Not necessarily Orson Scott Card's ansibles, but means of cutting through noise.
I agree with Max that there's a pretty darned small window of overlap. Perhaps there's a universal best medium of communications that we will eventually find. Perhaps someone else will be there, perhaps they won't.
Posted by: Ritchie Annand | October 25, 2006 12:33 AM
"If humans vanished tomorrow, how long into the future would human artifacts last?
What would be likely to last the longest? (Maybe some of the geostationary satellites??)"
I'd expect that our stuff on the moon and mars would stick around for a while.
Then there are the deep space probes.
Posted by: AoT | October 25, 2006 12:57 AM
Well, of *course* you should be skeptical there's intelligent life on other planets. There's reason to be skeptical there's intelligent life on *this* planet.
Posted by: "Q" the Enchanter | October 25, 2006 1:03 AM
Everything must have a first. I know it's very unlikely, but there is a chance that we are the first technological intelligence in the universe. If it were true, then the reason that there isn't evidence for anyone else, is a concern of a yet statement.
Posted by: bobryuu | October 25, 2006 1:40 AM
I'm inclined to think we'll be the first radio-using spacefaring civ for a long long distance, assuming we ever do become such a (spacefaring) civ, but I have to object to various points made.
The fact that only one species has human-level intelligence doesn't mean it's rare, not given the fact that we took over the planet with stone technology; our niche seems to be a global winner-take-all niche. The fact that it took X years to develop seems a better argument for rarity, though now we're in extrapolation from single-data-points territory.
Similarly, there are several species in the ape bottlenose crow raven raccoon octopus elephant cognitive space of sociality or tool use; that level of intelligence evolves at fair rates. A biologist might say there aren't that many such species, but I'd call bunk: intelligence pushes toward generalist niches, I think, so we'd expect fewer such species. What's more relevant I think is the amount of time that intelligent species have existed, and possibly how much of the ecosystem they controlled; unfortunately those questions may not be answerable.
Regarding the cost of interstellar travel, I'd note that multiple civilizations on Earth found it worthwhile to pile stones together into pyramids. People don't always go for what's economically sensible. And all it takes is one species to successfully spread from star to star to kick off a wave of colonization where replication is the reward.
The fact that we, whose science is rather young, haven't made a long-term artificial biosphere, seems a rather weak argument against the possibility of interstellar arks. Not to mention possibilities such as suspended animation -- never mind cryonics; genetically modify the species to self-suspend in hibernation! -- or AI/robots.
On aliens being bipedal, bilaterally symmetric, and humanoid: I think one can make a good case for a rapidly mobile species being bilaterally symmetric -- front/back matters, up/down matters, left/right doesn't -- and most species are such. Radial symmetry goes more with sessile lifestyles. Symmetry's a useful developmental trick so unlikely to not be used at all.
Clarke, Kubrick, Brin -- if you mean Brin's Uplift books, we were apparently the one species which *wasn't* uplifted by an alien race.
Posted by: Damien | October 25, 2006 2:36 AM
One more thing and then I'll let it go for the night.
In my post on TI, I take on how unreasonable the idea is of extraterrestrial intelligence -- or at least how improbable I think it is that we've been visited by aliens or ever will be visited by aliens.
I want to make this clear. I am not denigrating the idea of ET intelligence, though I have to admit this is a position of faith, not probability, not certainty. As others have noted, and as I intend to point out, we can't calculate odds -- so a discussion of odds is not valid, but it's all we've got to work with. This means that, until we have a lot more data than we currently do, the idea that intelligent aliens exist -- or that they do not -- is a sort of faith-based initiative.
What I find improbable, what I think is basically impossible, is the idea that we will ever meet another intelligent race in this universe, and I've tried to make my own SF in his area reflect my conceit. My characters live in a human-populated time, and they've never actually met aliens.
But I do maintain a shred of faith; I say so in my post there, and maintain it even though I go on to debunk my own statement. Why? Because I have to. I have to both believe in the idea of intelligent, technological life elsewhere in the universe -- and I have to be honest in saying I don't think we'll ever meet it.
And what I think is significant is that, in spite of everything I intend to do with the idea of aliens visiting Earth -- it's never happened, I think, and never will -- yet there beats in me, somewhere deep, somewhere resonant and probably irrationally hopeful, the idea tha there is intelligence out there somewhere, an intelligence we'll probably never know, because at least in part we can't. The distances are too much.
But that unknowing, that sense of tragedy in mourning for what could have been, if only fate had dealt a different hand ... well, that's something my inner poet tends to respond to powerfully. (Warning: The link points to a very long, very large excerpt from a book I've written, and will take a while to retrieve.)
I don't watch animé because it is animé, but there are some good animé that help present the feeling, the pathos behind what I'm suggesting here, a kind of romance of unbridgable gaps.
In this vein, if you want to catch a sense of the emotional flavor I attach to these depths, it might be worth checking out Voices of a Distant Star. It's a short story done as animé, and the pathos of human feeling juxtaposed with the terrible nature of the infinite is sweet, naive, charming and heartbreaking, all at the same time.
I want to believe in aliens. I just can't believe they've been here, or ever will be. In later posts on this subject, I'll explore all of this deeply. In so doing I hope to also explain how I can be a former goddite, current atheist, and still hopeful that even after Sol has gone nova there will yet be a legacy of wit to the cosmos, that we can still feel a kinship to them even if they live in a binary system and metabolize methane, regarding their suns with eyes sensitive to radio spectra and speaking, as another poster here once suggested, with grammar of phosphenes and color on skin instead of crude, blurry waves of compressed atmosphere.
As for what will remain of us in a million years: Plaques, footprints and tinfoil ships on Luna, vestiges of a distant and forgotten dream, as ephemeral -- and permanent -- as a cartouche in the bowels of a pyramid. The toys of children dreaming of godhood.
As to the ultimate fate of those gods -- no one can really say.
And there, I think, is the key to transcendence and tragedy.
Posted by: Warren | October 25, 2006 2:47 AM
Sorry PZ, but your quote here is illustrative of why you are right, but for entirely the wrong reasons:
"The simplest explanation for the reason that ET isn't tapping on our shoulder is that the Fermi and Drake assumptions are wrong--the kind of technological intelligence that might build spaceships and radios and harness fire is very rare, and techno-species are spread very thinly over vast and uncrossable tracts of space."
NO.
The SIMPLEST explanation is that such civilisations are reasonably common, BUT the state we are looking for, where we can communicate with them is very rare.
Why?
Because they are all (or almost all) on the other side of a technological singularity.
We are, ourselves, heading into such a singularity, and I expect we will pass through it in the next 50 years (I might even live to see it) - provided, of course, we don't set ourselves back by a major war between now and 2020)
See the works of Vernor Vinge, Chrles Stross, and others .....
Posted by: G. Tingey | October 25, 2006 3:05 AM
Additional thoughts...
I note soemone else mentions "The Singularity", but ...
VERY BIG BUT >>>>
A lot of you, including, I'm sorry to say, PZ, are effectively saying AGAIN, that: -
We're special, and Earth is special.
This has been knocked down time and again:
Copernicus, Galilei,Darwin, Hubble .....
And yet, it comes up again.
The so-called "anthropic principle" is another manifestation of this will-o-the-wisp.
It isn't true.
Please wake up.
Posted by: G. Tingey | October 25, 2006 3:14 AM
I would argue that I also happened in the Middle East, pre-Crusades. The Crusades in many ways started teh path to science in Europe, and destroyed the scientific community in the Midle East, letting the religious fanatics get into power.
Posted by: Kristjan Wager | October 25, 2006 3:17 AM
I was unfamiliar with the technological singularity crackpottery. I find it groovy and goofy.
Futurologists--is there a predictive profession with a worse track record? I mean, they make mutual fund managers look good.
The basic problem is there is just no sufficient data to predict AT ALL how often life should arise, and how often life should give rise to intelligence, and how often intelligence species should not go extinct long enough to find us. This makes the debate excruciatingly boring because anyone can say almost anything.
And the universe may be far more unhospitable than we even think, we've been here for a fraction of a moment of a cosmic eye-blink. Aren't there some kind of crazy astrophysical gamma zap-rays that just go off and sterilize big sectors of galaxies at random? I think I read about them in the NY Times. That'd be a good barrier to advanced civilizations exploring.
Posted by: miko | October 25, 2006 3:24 AM
What is interesting and susceptible to analysis is "physics bias" or perhaps more accurately whether determinism or contingency play the leading role in one's professional work. I suspect the ET optimists also tend to have a more progressivist (Whiggish) bias, both in general but particularly in regard to evolution. Dawkins, for instance, has on more than one occasion written that once life "gets going" (an improbable event, in his view) the emergence of intelligence is more or less inevitable, whereas the (extremely limited) evidence seems to point to life probably being ubiquitous and intelligence being exceedingly rare.
Posted by: johnc | October 25, 2006 3:49 AM
The Singularity (the core concept of which I'm increasingly inclined to think of as the Cognitive Revolution, focussing on mastery of a new technology and sidestepping eschatology) is to be based on exponential increases in information and communications technology, and understanding of intelligence. Why this would make a post-Singularity civ *less* able to communicate with us, I've never seen. I usually bridle at Techno-Rapture/Rapture for Nerds jibes, but in this context it seems appropriate.
"This has been knocked down time and again"
The Copernican principle of mediocrity, of assuming we're average and in the middle, can work only if there's a distribution to be in the middle of, and even then it doesn't always apply. On Earth we *are* special: we have the biggest brain/body ratio, we dominate the ecosystem, etc. In the solar system Earth *is* special with regard to supporting complex life. There's no distribution of DNA codes on Earth, with us being in the middle; there's basically just one code. Might be the best, or it might be the first and only to arise on our planet.
If technological civs are stuck in their systems, there may be many of them out there. If such civs 'tend' to spread through the stars then there's likely to be no tendency, just a single-source civ taking over the galaxy. The fact that we exist at all and the galaxy is fairly easy to explain with simple physics suggest no such civ is out there yet. It'd be unlikely for us to be the first civ if there were more than one civ, but if the first civ is the only civ (because it suppresses competition) then it has a good chance of being us.
Posted by: Damien | October 25, 2006 3:55 AM
OK. But then what was that anal probe all about?
Posted by: joshua | October 25, 2006 4:01 AM
You know, I get the feeling intelligent life is inferior to microbial life. You can find microbes almost anywhere--hundreds of feet below ground, in thermal vents, Apollo space capsules--and here we are, huddled together in a few temperate zones drifting on glorified islands, looking up at the stars with parasite ridden eyes and wondering why nobody else bothered with our way of life.
LOL! Baratos, your quote is simply brilliant. I'll put it up on my blog.
The SIMPLEST explanation is that such civilisations are reasonably common, BUT the state we are looking for, where we can communicate with them is very rare.
Why?
Because they are all (or almost all) on the other side of a technological singularity.
G. Tingey, I agree with you that communication is a problem, but there may be factors other than technology.
For example, when people study wild animals they wear camouflage so as not to disturb them. It's entirely possible that intelligent ETs have been consciously trying to avoid detection while observing us from a safe distance.
Because we are such temperamental, irrational bastards. Or simply because they don't like us. That sort of thing happens.
Posted by: LH | October 25, 2006 4:27 AM
Nobody has mentioned the recent Sciam report on space travel and the problem of Cosmic rays. Sending life into space is very difficult (sending objects into space is relatively easy however). We should be looking for microscopic-space robots not beings. There might be a few of them in your garden.-)
Posted by: reason | October 25, 2006 4:54 AM
Just my 2p..
As far as the technological singularity goes, I'm quite skeptical - especially about the timeframes. The whole argument seems to rest on a small number of exponential trends extrapolated several decades into the future, which is somewhat dubious. But over a couple of centuries... perhaps.
If you have an asteroid belt like our solar system, and have harnessed fusion power, then building a generation ship of sufficient size shouldn't present massive difficulties. If, of course, you've managed to transfer your intellegence to a electric/mechanical substrate, then simply powering down for a few hundred years makes such travel simple.
As far as life goes..
Simple life (bacteria) is, I expect, very common. Most of the more reaistic systems for abiogenesis I've seen should be common.
Getting more complex involves solving a number of problems. Photosynthesis is vital - without it you rely on the difference between the reducing interior of the planet and the fact that the action of the parent star on the atmosphere of the planet will make it slightly oxidising. So life-under-ice is only ever going to be very small scale; for Europa, for instance, the only source of energy for biology would be communication with the oxygen atmosphere, since the sub-ice ocean would be in equlibrium with any volcanic vents.
Waterworlds would be a better bet, but quite possibly subject to either freezing solid as in Europa or boiling via super-greenhouse effects, there being no way of 'drawing down' carbon dioxide. However, this may be good - it might mean that any planet with water will progressively lose it to 'boiling off' until land is exposed and carbonates can form. That would be good news - without land, it's very hard indeed to see how technology can evolve; sea creatures can't light fires.
On the subject of fire and ice; another problem is one of rotation. The planet must rotate, and the axis can't point at the star - and this requires that either our planet has a large, stabilising moon or (perhaps) is itself a moon of a gas giant. Otherwise you will quickly lose all of your water to an ice cap on the dark side.
Assuming you have such a planet, it also has to stay in the habitable zone for sufficient time. This zone moves outwards with time as the parent star progresses through the main sequence - for instance, within the next billion years, the inner edge of the Sun's habitable zone will pass earth, which will 'do a Venus'.
So earth is quite 'special', or at least rare.
So, IF you have a planet with the right conditions, then life will almost certainly take root. There are further complications regarding the galatic zones - near misses from other starts being quite terminal; but presuming that no planet killer impacts happen, intelligence is probably quite likely. Over a sufficiently broard timescale, it does appear that the most intelligent creatures on the planet become more intellegent; this probably reflects a very drawn-out process of brain evolution - changes in organisational complexity of the brain.
So I'd suggest that the evolution of technolgical intellegence is highly likely.. BUT the requiste planet is far less likely than is often supposed. Earth has been an extremely stable environment for around 3.8 billion years.
Posted by: Andrew Dodds | October 25, 2006 5:09 AM
The Fermi Paradox is utterly bogus. The Drake equation itself is hand-wavy enough, but then it doesn't claim to be more than a guesstimate.
But we have *NO IDEA* how to travel beyond our own solar system, still less how to set up a successful colony when we arrive at a destination. So the extrapolation of the Drake equation to a rate of spread through the Galaxy is based on nothing. The Fermi paradox assumes that the only factor involved is velocity - in which case why aren't there dinosaurs living on Mars? After all, they had plenty of time to walk there...
I mean, it's just laughable.
It's perfectly possible that there are lots of intelligent alien species out there, all trapped within their own solar systems, and not able to communicate with each other. As others have pointed out, we'll drop off the EM radar soon as compression techniques turn our communication into something resembling background noise.
Until we have working interstellar travel ourselves (if we ever do), and working interplanetary colonisation, any and all hypotheses involving interstellar travel (such as the Fermi Paradox) are nothing more than hot air.
Posted by: Peter Ellis | October 25, 2006 5:28 AM
I, too, welcome our hominid overlords... Oh, wait.
[Or, equivalently: Woof!]
The rest of the primates are confined to equatorial neighborhoods, delicate energy-hungry creatures. (Whom some of us continue to eat.) Ours is not the dominant order. God loves beetles more.
It's not out of the question that we might eventually visit and possibly colonize other planets, but it does seem presently more pressing to stabilize our own effects upon the planet on which all of us presently dwell.
Posted by: bad Jim | October 25, 2006 5:41 AM
Of course, communicating with life on waterworlds is going to be difficult. For example, how would a civilization of tool-using cephalopods develop electronics for radio communication? Oh well.
Posted by: j.t.delaney | October 25, 2006 5:50 AM
There's another possibility, of which PZ must be aware (it was mentioned in James Cameron's Aliens of the Deep): that complex life, even intelligence, is far more likely to evolve on hydrospheres like Europa. Being aquatic, such beings would be indifferent to the topside of the ice, and would never see stars. (Though imagine the Magellanic voyage of such a being who dared to penetrate the surface!)
Posted by: Grumpy | October 24, 2006 10:19 PM
So squid, then?
More seriously, isn't there a degree of disconnection between the assumed difficulty of evolution and that of interstellar travel here? Everything we know about space flight suggests that interstellar travel and communication are incredibly difficult, expensive and of marginal utility/
Posted by: Alex | October 25, 2006 5:54 AM
Well I can think of one very good reason: money.
It just isn't worth it to travel in space. Why? No reason to go in the first place, and if there was, no way to collect on your investment.
Consider. Why did the Europeans explore and colonize the world? Because of the things they could bring back from places like Asia (spices and fine cloth) and the Americas (coffee, gold etc). All of these things share a combination of relatively small bulk and relatively high value.
There was an incentive to go, and people did. The technology developed and off we went.
But space? What do we expect to find on Mars? A planet on a nearby star? Just more of what we have here. Mostly rock, iron ore, nickel etc. Large, bulky and low value.
Unless someone can give a good economic reason for going, no-one ever will.
OK - so sometimes it's argued that the costs of interstellar travel will become low enough that some billionare might just throw some money at it in the hope of making something.
That's not going to happen - the payoff will never be there. Consider that getting to A-centurai would take about 10,000 years and a further 10,000 to get back. Let's say it cost $1M. $1m compounded at the long term interest rate of about 6% is a vast sum - many orders of magnitude greater than the value of any amount of gold you could bring back (assuming that the ship can carry it's own weight - or even 100 times it's own weight). Much better to leave the money in the bank (ie. invest it on Earth)