Pharyngula

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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.


DarkSyd asks a question:

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

  1. #1 Numad
    October 24, 2006

    “technological intelligence”

    Technological being the keyword, I think.

  2. #2 Mike
    October 24, 2006

    “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

  3. #3 H
    October 24, 2006

    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.)

  4. #4 Aaron KinneyAaron Kinney
    October 24, 2006

    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.

  5. #5 Oxhead
    October 24, 2006

    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?

  6. #6 Warren
    October 24, 2006

    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…

  7. #7 Scott Hatfield
    October 24, 2006

    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

  8. #8 jeffw
    October 24, 2006

    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.

  9. #9 James
    October 24, 2006

    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.

  10. #10 marsha
    October 24, 2006

    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.

    😛

  11. #11 Trip the Space Parasite
    October 24, 2006

    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.

  12. #12 poke
    October 24, 2006

    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).

  13. #13 prufrock
    October 24, 2006

    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.

  14. #14 Bryson Brown
    October 24, 2006

    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.

  15. #15 Max Kaehn
    October 24, 2006

    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.

  16. #16 Hank
    October 24, 2006

    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.

  17. #17 oldhippie
    October 24, 2006

    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…

  18. #18 Kurt
    October 24, 2006

    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.

  19. #19 SLC
    October 24, 2006

    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.

  20. #20 Mena
    October 24, 2006

    There’s always this possibility.

  21. #21 carlosmorales
    October 24, 2006

    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.

  22. #22 Bronze Dog
    October 24, 2006

    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. 🙂

  23. #23 Diego
    October 24, 2006

    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? 😉

  24. #24 Great White Wonder
    October 24, 2006

    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.

  25. #25 Grumpy
    October 24, 2006

    “…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.

  26. #26 Warren
    October 24, 2006

    Marsha:

    Ok, but what about the dolphins?

    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.

  27. #27 Avian
    October 24, 2006

    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.

  28. #28 Grumpy
    October 24, 2006

    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!)

  29. #29 Arun
    October 24, 2006

    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??)

  30. #30 Caledonian
    October 24, 2006

    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.

  31. #31 Jacob
    October 24, 2006

    Quick question: Has anyone here read Stephen Baxter’s “Manifold Trilogy”?

    I’m just curious.

  32. #32 llewelly
    October 24, 2006

    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?

    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?

  33. #33 Baratos
    October 24, 2006

    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.

  34. #34 BC
    October 24, 2006

    …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.

    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).

  35. #35 llewelly
    October 24, 2006

    I, for one, Welcome our new, one-neuron parasite overlords.

  36. #36 jeffw
    October 25, 2006

    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.

  37. #37 Warren
    October 25, 2006

    Caledonian:

    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.

    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.

  38. #38 Ritchie Annand
    October 25, 2006

    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.

  39. #39 AoT
    October 25, 2006

    “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.

  40. #40 "Q" the Enchanter
    October 25, 2006

    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.

  41. #41 bobryuu
    October 25, 2006

    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.

  42. #42 Damien
    October 25, 2006

    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.

  43. #43 Warren
    October 25, 2006

    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.

  44. #44 G. Tingey
    October 25, 2006

    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 …..

  45. #45 G. Tingey
    October 25, 2006

    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.

  46. #46 Kristjan Wager
    October 25, 2006

    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).

    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.

  47. #47 miko
    October 25, 2006

    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.

  48. #48 johnc
    October 25, 2006

    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.

  49. #49 Damien
    October 25, 2006

    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.

  50. #50 joshua
    October 25, 2006

    OK. But then what was that anal probe all about?

  51. #51 LH
    October 25, 2006

    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.

  52. #52 reason
    October 25, 2006

    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.-)

  53. #53 Andrew Dodds
    October 25, 2006

    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.

  54. #54 Peter Ellis
    October 25, 2006

    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.

  55. #55 bad Jim
    October 25, 2006

    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.

  56. #56 j.t.delaney
    October 25, 2006

    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.

  57. #57 Alex
    October 25, 2006

    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/

  58. #58 James
    October 25, 2006

    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)

    Sometimes (noteably in “The Anthropic Principle” by a Barrow and Tipler) it’s argued that our investor should send people, let them establish a colony, wait a further 500 years until it grows to an economy the size of the US and then take his money.

    How? The 300 million people over there with their thriving economy are *not* going to just hand it over. Remember what happened when Great Britain tried to tax the 13 colonies? Revolution anyone?

    No. Space travel might very well be possible, but it isn’t practical.

    There could be any number of technological civilizations out there, but none would find exploration justifiable.

    Fermi was wrong. Motive is needed as well as intelligence and capability.

    SETI provides a demonstration of this. SETI argues that we should listen because there must be someone out there shouting. Well we aren’t shouting so why should they. If they’re rational they’ll do the same as us and just listen.

    PS – some might argue that money is just a cultural construct and that aliens might not have it. That’s true, but they definitely have something – the motivation to grow that is a defining characteristic of life. They’ll measure it somehow and however they do it, exploration won’t be worthwhile.

    The fact that just now we use money as the measure is irrelevent. Life is always looking for more no matter how it’s measured.

  59. #59 G. Tingey
    October 25, 2006

    More comments:
    “We should be looking for microscopic-space robots not beings. There might be a few of them in your garden.-) ”

    They are called StarWisps ……

    Rarity of life at all:
    From Dawkins…(and others):
    Even if life is a “billion (10^9) to one chance”, then there are a billion planets in this galaxy with life.
    Eukaryotic life – probably something like a thousand-to one against – which leaves a million.
    Multicellular life – down to a thousand now? Or more – still up in the 10^5 range? I don’t know.
    “Intelligent” life?
    THAT’S the really difficult one.

    “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.”

    Codswallop – see below…
    The Drake equation is emphatically NOT nonsense, but what we still really don’t know are the values to put into some of the parameters. However, we are getting much better results now, than we were even 20 years ago, thanks to various spaceprobes. Planets are a LOT commoner than we thought. Soon we will be able to know for sure if planets in the goldilocks zone are common or not.

    And, of course, there is no prohibition against FTL – what there is is a prohibition against transiting “c” in/with a material object.
    SF-type “warp” drives are not prohibited, just very, very, very difficult (impossible with present or foreseeable technology, but not theoretically impossible) though there really is a lot of hand-waving here.

    “Earth has been an extremely stable environment for around 3.8 billion years.”

    NO.
    Ever heard of “Snowball Earth”?
    The end-of-Permian extinction?
    Yet life survived and adapted, and changed, and became more complex, probably at least partly because of those environmental stresses, driving adaptation.

    The singularity will occur when:
    We get true AI – which will occur (probably) when we get a multi-processor set running a lot of quite small processors (proabably no more than 1kb capapcity each) but connected in a cube, 1000 processors-to-a-side, so you have 10^9 processors, with each connected to its’ 14 nearest neighbours. The “big S” may occur sooner – but we don’t know – that is why it is a singularity.

    The real benefit of some physics training is that it enables the user to put limiting parameters and constraints into a system. You can then look for solutions inside that envelope. As ones’ knowledge improves, the envelope shrinks until a solution is percieved as emerging.

    This is happening now in particle/subatomic physics, where we are going to know for sure, whether “string” theory is a valid model or not (I’m betting against strings, BTW, but I could be 100% wrong – thaty’s part of the fun!)

  60. #60 Dr VON Scott
    October 25, 2006

    I am concerned by the lack of vitriolic censor directed at Prof. Myers for his obvious disrespect for Physicists. I would like to point out that Physicists are gods, and everything we say is true. We are also very clean. I myself was once an aquarius with an interest in ball point pens, but now that I have given my life to Physics I wash regularly and have put away the things of childhood (the pens).

    I have to go back inside now, thank you for your time.

    PS. Have you never wondered that Fermi felt the need to INSIST that there were no aliens on this planet? I suggest that you look very closely at your personal picture of Fermi. For no longer than an hour. Unless you have two copies of the picture.

  61. #61 Paul
    October 25, 2006

    If anything intelligent ever gets off this rock in a permenant way, it won’t be us. All those SF fantasies of jump-suited humans whizzing around the cosmos in tin cans are just that – fantasy.

    The best we’ll do is AIs, colonies on the nearer and more habitable moons/planets of this solar system (inhabited by people with significantly re-engineered biology) and very large asteroid slow ships, carrying fleshies that are significantly different biologically (not to mention socially) to us in order to adapt to the conditions of living in a hollowed-out rock with pretty much finite resources (once you get outside the Oort cloud) for pretty much ever.

    Assuming of course, anyone can be assed doing all/any of that, and has the necessary significant percentage of planetary GDP to do it for the necessary length of time.

    Going to the stars is harder than we know and it’s pretty certain that we savannah apes, as elastic and adaptable as we are, are going to need to change ourselves (or create machines to carry our intelligence offworld) to have any chance of doing it.

  62. #62 Tristram Brelstaff
    October 25, 2006

    Physicists are optimistic about SETI because they know the sheer size of the Universe whereas biologists are pessimistic because they know that life on Earth has had 3.8 billion years and has still only produced us.

  63. #63 T_U_T
    October 25, 2006

    There could be any number of technological civilizations out there, but none would find exploration justifiable.

    This is utterly unrealistic. Even here on earth there are a LOT of people who would colonize space just for the sake of it. Thinking that ANY civilisation gives up because it does not produce immediate financial profit is rather far-fetched.

    Life is always looking for more no matter how it’s measured.

    Yeah – and life in thousands of colonies is more than life on only one, no matter how it’s measured.

  64. #64 andold
    October 25, 2006

    “… 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.”

    But isn’t the larger point that all the evidence we have is that if life does originate somwhere, it WILL develop intelligence?

    In our experience, it’s a one-to-one relationship.

    And, as far as appearing only once, weren’t Neanderthals intelligent? Not to mention that an if intelligent species appears, will it tolerate others?

  65. #65 T_U_T
    October 25, 2006

    Depressing as it may be, Homo sapiens will someday go extinct. Get used to that fact.

    And, also… If we are to get stuck here with no hope to escape, and our species is doomed to extinct without progeny, why you are so adamantly against drugging the mankind with religion=the opium for the masses ? Hopeless patients are given morfium, aren’t they ? Why to oppose rapturist and other doom cults ? If a dying patient wishes for the euthanasia, her wish should be fulfiled, shouldn’t it ?
    Is there any reason to fight for the progressive cause, if all progress leads only to a stalemate, and the best one can do, is to make her waiting for death comfortable ?
    I don’t know, but I think, that having my bets on space expansion I can not lose, no matter how small the chance is, because there is no cost of being wrong – if we fail, we go extinct anyway…

  66. #66 Jeremy
    October 25, 2006

    I liked the Douglas Adams line about how Earth somehow sent out a signal and insulted a galactic warlord, who summoned 10,000 ships to go annihilate us and, due to an error in scale, was promptly swallowed by a Yorkshire terrier. Or something like that.

    SETI is worth keeping around, just in case, but I wouldn’t bet on it. We have absolutely no idea what kind of intelligence has evolved, or if it’s even remotely interested or capable of technology. Maybe they spend their time sitting around singing songs.

    Another possibily comes to mind from Jared Diamond’s “Guns, Germs, and Steel”. Even if some planet was like ours, and some sort of tool-using/making terrestrial species developed, what if all the continents are like the Americas or Africa, spanning the equator. It didn’t seem likely that, left on their own, the Native Americans would’ve developed too much further than the stone age (and one tiny metal-using civilization). Or maybe they’re all on islands like the Polynesians. They wouldn’t be able to form a large enough population to have agriculture and sustain an intellectual class. And even if they could, who’s to say they’d develop science. Maybe they’re all religious and are waiting for the Rapture or whatever their equivalent is.

  67. #67 zhaphod
    October 25, 2006

    Another possibility.

    Intelligent life froms do evovle more than occasionally in the universe. But also natural events like suprenovae are also quite common which can simply sterilize a whole planet if they happen to be close by. So may be we are extremely lucky to be still around.

  68. #68 Warren
    October 25, 2006

    Okay, I lied.

    Your post, BTW, is on TI now. See my reply there for the reason for the delay.

    G. Tingey:

    “We should be looking for microscopic-space robots not beings. There might be a few of them in your garden.-) ”

    They are called StarWisps ……

    I haven’t met any of these. What are they alleged to be?

    Rarity of life at all:
    From Dawkins…(and others):

    Citation, please.

    Even if life is a “billion (10^9) to one chance”, then there are a billion planets in this galaxy with life.

    Not so. There aren’t even a billion stars in this galaxy.

    In order for the foregoing to be true, there would have to be one billion times one billion planets. Pay attention to the numbers you cite, please.

    You then call Drake “hand-waving”, but then go on to say this:

    And, of course, there is no prohibition against FTL – what there is is a prohibition against transiting “c” in/with a material object.

    Cite me one reference from a legitimate physicist who will agree with the foregoing.

    There is a prohibition against information, matter, meaning being transmitted FTL. If you deny this, it would seem you have less understanding of the universe than does the average high school graduate.

    SF-type “warp” drives are not prohibited, just very, very, very difficult (impossible with present or foreseeable technology, but not theoretically impossible) though there really is a lot of hand-waving here.

    Indeed there is — in the camp of those who assert that SF type warp drives are even remotely plausible.

    “Earth has been an extremely stable environment for around 3.8 billion years.”

    NO.

    YES.

    Ever heard of “Snowball Earth”?

    Oo, you mean the times when the mean surface temperature dropped to minus ten or twenty Celcius, but left the troipics still warm and pleasant, and the volcanic zones downright sultry?

    Gosh, I guess that’s a much harsher range than +3 absolute zero in vacuum versus +10K or so on a star’s surface, huh?

    The end-of-Permian extinction?

    Which was nearly matched by the Cretaceous die-off, or the Devonian schism, or the Cambrian collapse.

    Right?

    So you find occasional stochastic extraterrestrial impacts to be evidence that life is inherently fragile? I’d suggest the opposite to be true…

    Yet life survived and adapted, and changed, and became more complex, probably at least partly because of those environmental stresses, driving adaptation.

    Wrong. The Burgess Shale shows us that early multicellular diversity was actually much more broad and complex, in terms of speciation, than was life just after the collapse of the Cambrian era.

    As for the rest of your comments — sorry, they’re based in even more speculation than my own, and I confess to being wildly faith-based when I say intelligent life might exist out there somewhere, but we’ll never meet it, if it exists.

    If you want to carry on this discussion with me particularly, you’re welcome to do so in the space for it on TI, where I think your posts should be off filter now. (Sorry they were at first held back; again, see my site for why I tend to spam-block there. It’s not personal. Everyone has that on the firat comment.)

  69. #69 Caledonian
    October 25, 2006

    There are a hundred billion stars in our galaxy, approximately.

    Go stuff it, Warren.

  70. #70 Torbjörn Larsson
    October 25, 2006

    The basic SETI observation seems to be that biologists and physicists sees markedly different perspectives and outcomes. I must admit to some curiosity to learn about astrobiologists views.

    The Drake equation and its extensions is at the core of the problem in so many ways. Whatever one makes of them, guesstimates, constraining probabilities, or describing plausibility due to lack of observations, the fact that they exist have the power to elevate the analysis from faith as long as one is cautious. The alternative to the equations would be to either assume a civilisation per star system from the cosmological principle, or give up the problem. I don’t think any of those alternatives are attractive.

    The question the equations pose is the famous one: “Where are they?”. But due to lack of observations and knowledge we don’t really know yet if a negative observation tells us much. The distances makes communication or travel hard and expensive, other opportunities are distractors, et cetera.

    This is why I don’t get what a “dim view” of SETI is. The very question the Drake equation pose, SETI, should definitely be explored as much as we want to put resources and curiosity in it. On the other hand, the answer of ETI is an uncertain outcome.

    Admitting that we don’t know enough yet to get a ready answer from the nonobservation, it is tempting indeed to go on discussing the innards of the constraining factors. Usually there is a display of more or less skewed assumptions.

    One assumption is that evolution isn’t directed. But what does it mean? It could be that each hurdle, multicellularity seems to have been a major one, photosynthesis another one, may have some probability of not being cleared. But once they do, what constrains evolution to explore the possible solutions? (A naive model would be to imagine an analog to a diffusion process, from a very ‘unprobable’ point source.) AFAIK there is some recent results that show that ecological systems indeed are stabler when complex, ie niched and interdependent, so there could even be evolutionary pressures towards that end?!

    Another assumption is that intelligence is rare. But I have seen neuroscientists argue that domain-general mechanisms can explain all results with some rare pathological exception so far. So if multicellular movement naturally selects for a brain cluster, what restricts general intelligence then?

    Supporting such speculations are a recent paper that shows for the first time symbol representation behaviour in a moderately complex neural net. ( http://develintel.blogspot.com/2006/10/generalization-and-symbolic-processing.html ; though the paper discussed prefers another description.)

    It seems to me Mayer complicates too much. He thinks ETI’s must be adapted to have sense organs for “electronic signals”. (As Sagan, I belive he means EM radiation.) First, I find it difficult to see why photosensitivity isn’t an option for access to an ubiquitous and rich energy source, though I admit per above it may be a hurdle. But many chemicals are photosensitive… Second, we have used technology to observe events and signals we can’t ourselves sense.

    That said, I don’t like the observerdependent or single observation conclusions some make. That we are the only species to have developed a technology surpassing stone tools is an observer effect; we are the first and we are also the first to ask the SETI question. It also means that SETI technology is possible, not that it is a certainty or “probability” once life started. One observation makes no probability.

  71. #71 Torbjörn Larsson
    October 25, 2006

    “of course, there is no prohibition against FTL – what there is is a prohibition against transiting “c” in/with a material object.”

    There is also a prohibition for signals to exceed vacuum speed – it destabilises gauge fields. (I can give ref to a paper that seems valid.) Tachyons are AFAIK temporary when vacua and spacetime global geometry pass a discontinuity.

    Looking at allowed spacetime deformations travelling FTL for warp drives, there is also a prohibition about global timelike loops that could occur for the travellers. There is a (tenious) argument from the observation that all Turing systems are equivalent to NP != P holds to no timelike loops holds. (I love that – from CS to physics!)

    “Physicists are optimistic about SETI because they know the sheer size of the Universe whereas biologists are pessimistic because they know that life on Earth has had 3.8 billion years and has still only produced us.”

    I believe this is one of the reasons for the different outlooks. (Apart from that physicists don’t know biology or vice versa.) It also means that we have plenty of examples of planets but not of life and technology. (Though earthlike planets at earth distances are the hardest to observe, so it will be a while.) It is bound to make a difference in views.

    “But also natural events like suprenovae are also quite common which can simply sterilize a whole planet if they happen to be close by.”

    IIRC there is speculations that since the suns have done about 20 circuits around the galactic center, it was very unlikely to find that we have not passed through a galactic arm during sterilising starburst formation from supernovas. OTOH no one understands the dynamics of the arms yet AFAIK…

  72. #72 jeffw
    October 25, 2006

    Interesting SETI article on the Allen Telescope array. I haven’t been following SETI for years. It seems that even though search technology is much better, they’re looking for needle in haystack:
    http://www.seti.org/site/apps/nl/content2.asp?c=ktJ2J9MMIsE&b=194993&ct=3018071

  73. #73 Umilik
    October 25, 2006

    Why would anybody with any degree of intelligence find us interesting enough to swing by for a visit ?
    Alien 1: well we have picked up some transmissions from this little blue planet over there. Best we can determine there are pre-intelligent beings on it, but they seem to have some irrational belief system in some sort of “higher power” they assume made their planet and everything on it in 7 days.
    Alien 2: Hmm, let’s give them another 5000 years to grow up before we schedule a visit.

  74. #74 DouglasG
    October 25, 2006

    Since the dawn of civilization, we have been on the brink of destroying civilization. I think intelligence lives on this brink at all times and sometimes it topples over.

    Last time I crunched the numbers, I came up with 63 technological civilizations. That 1 in a billion chance of progressing beyond the simple life is the kicker!

    Finally, the universe is an inhospitable place for us big brained air breathers. Expanding beyond our solar system, is going to cost mucho buckos! ($$$). Why would we do that when we have TV?

  75. #75 Bartholomew
    October 25, 2006

    Nice quote from Annie Dillard I found here:

    …For the ability to conceive and execute murals and epic poems and symphonies and novels is a grotesque trick of tissue which sprang from the pot of the possible, like the grossly overdeveloped antlers of the extinct Irish elk…We create value and locate it in our monstrously overdeveloped mental self-replication, our stuttering repetitions of our brains’ own order, with which we have covered the gibbering earth.

    John Sutherland, though, attributes the analogy to Kurt Vonnegut:

    The firm belief that ‘dumb is good’ underlies the Oscar-winning success of films like Forrest Gump…Our big brains, Vonnegut has argued, are like the elk’s absurdly overdeveloped antlers or the peacock’s unnecessary tail. They won’t, in the long run, help our species to survive.

  76. #76 Jason M. Robertson
    October 25, 2006

    I’ll second that endorsement of Blindsight.

  77. #77 damian
    October 25, 2006

    I’ve always thought the Fermi paradox was bunk because one of the assumptions was just the time taken to go from star to star. So it was like the ultimate “are we here yet?”; the spacefarers just arrive at the star, yell “we made it” and then immediately take off for the next star. They wouldn’t do that; they would likely settle down and spend generations on their new home.

    The other problem the physicists don’t take into account is what I call biological quarantine. Say we found another Earth like world. Just because it exists doesn’t mean we humans can survive on it. It may have its own biology, ecosystems, viruses, germs, etc that may be lethal to us.

    Then there is the psychological aspect of space travel. Who of us after 12 hours on a plane hasn’t been dying to get off? Generation ships be damned; we have no idea how to build them, nor do we know how to keep people happy if they’re cooped up inside for a year, or 10 years or how to feed them that long. Even travelling to the just far corners of our own solar system is going to be challenging, forget the stars.

    That’s why we really have to take care of the Earth; it’s the only place we’ve got. That’s why I find our tendency to trash it alarming. We have no escape.

  78. #78 chuko
    October 25, 2006

    Wait a sec.. Sagan said,”an overall trend toward intelligence can be perceived in the fossil record.” Ok, I’m just a physicist, but isn’t this true?

    If I were to plot something related to intelligence, like brain size or nervous system complexity or something, of the creature with the biggest/best brain in existence, over time, it would go up. And that would roughly true over hundreds of millions of years, right?

    So, sure, average intelligence isn’t going up, at least not much — most critters are bacteria. But the fossil record does show a pretty steady increase in the intelligence of the most intelligent animals, which is what we’re interested in when talking about the possibility of extraterrestrial intelligence. Why isn’t this an evolutionary trend toward intelligence?

  79. #79 sgage
    October 25, 2006

    “We have absolutely no idea what kind of intelligence has evolved, or if it’s even remotely interested or capable of technology. Maybe they spend their time sitting around singing songs.”

    That’s what I’ve always believed. Real advanced intelligences would have bigger fish to fry than exploring the galaxy, or whatever 🙂

    Another explanation for Fermi’s Observation is that there’s some sort of Prime Directive – no interference with the natives! 🙂

    – sgage

  80. #80 Will Von Wizzlepig
    October 25, 2006

    Ooo, nice thread.

    Citing our own evolution patterns as evidence against the possibility of other intelligence in the universe does not seem fair.

    Yes, we were a very, very unlikely outcome.

    And yes, we can guess that it is unlikely for life to emerge given environmental factors which vary beyond a certain range.

    Is it possible that the chance for intelligent life may be higher from another point within the set of variables including: (distance from sun/temperature), (gravitational force), (chemical makeup of home planet), (surrounding stellar bodies)?

    I feel like the argument that by observing our own evolution we may postulate the unlikeliness of it occuring elsewhere seems perilously close to, albeit completely different from, the argment that intelligent life here did not actually evolve into being.

    ;D

  81. #81 Damien
    October 25, 2006

    “But we have *NO IDEA* how to travel beyond our own solar system”

    Sure we do; use a combination of rockets and gravity slingshots. We already have a few interstellar probes (the Voyagers, maybe the Pioneers, I’m not looking it up.) What we don’t know is how to survive through the millennia that the speeds we can achieve would require, and the easiest thing to try with current tech, a generation ship, isn’t that appealing. But I think it could plausibly work if we tried, unlike a Bussard ramjet.

    And as far as aliens, imagine a race which inherited hibernation abilities.

    “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.”

    Yes, that analogy is laughable. Dinosaurs could not physically reach Mars. We can, and we can send stuff to Alpha Centauri too. The basic problem is our biology, not physics, though the usual hope is to use better physics to make the biology problem go away.

  82. #82 Damien
    October 25, 2006

    “I’ve always thought the Fermi paradox was bunk because one of the assumptions was just the time taken to go from star to star. So it was like the ultimate “are we here yet?”; the spacefarers just arrive at the star, yell “we made it” and then immediately take off for the next star.”

    No, that’s not part of the assumption. You can spend 1000 years on travelling to the nearest star and another 1000 years building up a civilization wealthy enough to send another expedition and still fill the galaxy in 50 million years.

  83. #83 Pygmy Loris
    October 25, 2006

    Jeremy,

    I’m wondering why you feel the need to say

    what if all the continents are like the Americas or Africa, spanning the equator. It didn’t seem likely that, left on their own, the Native Americans would’ve developed too much further than the stone age (and one tiny metal-using civilization)

    One of the most convincing arguments for why state-level society was a late comer to the Americas is the difficulty of domesticating the native plants and the lack of appropriate beasts of burden to domesticate in most of the hemisphere. Also, many Native American societies used metals (copper decorations are common). The use of metal for weaponry is pretty much absent. I don’t see that as a problem though.

    Your statement implies that there is some sort of inherent defect in Native Americans that made them incapable of developing “civilization.” Furthermore, Africa had “civilizations” (Egypt, Ethiopia, Timbuktu) that lost much of their prestige and power with the discovery of the New World.

    Also, you’re confusing technology of jungle societies to equatorial societies. They’re not the same.

    Finally, in the New World (and parts of the Old World) concepts like the Stone Age are pretty much useless. The division of the archaeological record into such time periods as the Stone Age, Bronze Age etc. is Euro-centric and not indicative of technological developments in the rest of the world.

  84. #84 Damien
    October 25, 2006

    “Why did the Europeans explore and colonize the world?”

    Why did Polynesians explore and colonize the Pacific? It *wasn’t* for trade. Why did Vikings settle in Iceland, Greenland and (not very successfully) North America? Again, not trade.

    “That’s not going to happen – the payoff will never be there.”

    What’s the payoff for the billionaire being a space tourist? Certainly not financial. The whole point of invoking eccentric billionaires is that they can afford to do expensive things for non-financial payoff, such a warm feeling from having the human race not confined to Earth.

    “There could be any number of technological civilizations out there, but none would find exploration justifiable.”

    There are many people living, including some reading this thread (say, me) who’d happily fund a interstellar journey if they could afford to. It’s a purchase, not an investment (unless you go with the colony), but some people want to make that purchase.

  85. #85 Damien
    October 25, 2006

    Your statement implies that there is some sort of inherent defect in Native Americans that made them incapable of developing “civilization.”

    Pygmy Loris, the fact that Jeremy invoked continents spanning the equator suggests to me he’s read the same book you have, though I think continents running north-south is the real distinction. The defect isn’t in the Native Americans but in the Americas.

  86. #86 Pygmy Loris
    October 25, 2006

    Damien,

    You’re right. We both read Diamonds Guns, germs and steel. However, I find Diamond’s a priori assumptions to be a methodological problem that calls the whole endeavor into question. And I didn’t like the way Jeremy phrased his comment. he probably was refering to the supposed unsuitability of the environment Native Americans lived in, but the manner he chose to relay that idea makes it sound like the defect was with Native Americans, not the environment.

    And I’ve read many other books about civilization and archaeology and why social development follows different tracks in different parts of the world.

  87. #87 Erasmussimo
    October 25, 2006

    I’d like to point out the fundamental irony of an evolutionist arguing against extraterrestrial intelligence. On the one hand, the evolutionist argues (quite rightly) that the origin and development of life on this planet was a natural process arising from the combination of extremely improbable events arising out of extremely numerous trials. Exactly the same argument applies to the evolution of technological intelligence. The only things we know about such a development is that it is extremely improbable, and that there are an extremely large number of possible sites for such development. To argue that the latter development is not plausible while simultaneously arguing for the former explanation seems contradictory to me.

    We don’t know the numbers here. What is the probability of a biosphere developing intelligent life? 10**-6? 10**-8? 10**-10? We don’t know. How many biospheres are out there? 10**6? 10**8? 10**10? We don’t know. So why don’t we just admit to ourselves that we don’t have the numbers to make this call. The Fermi Paradox is our best evidence, and so tentatively we have to accept the hypothesis that technological intelligence has not developed in this galaxy. But let’s also admit that the Fermi Paradox is a pretty thin layer of ice.

    I will take the argument one step beyong the Fermi Paradox. Let us exclude the concept of local exceptionalism — let us acknowledge that we are unlikely to be in any fashion particularly special in the universe. Add that to the Fermi Paradox, and you get the conclusion that we will never reach the stage of being able to colonize other planetary systems. Yet any reasonable extrapolation of the current pace of technological improvement suggests that we are likely to attain that capability within 100 – 200 years. Therefore, our civilization seems to be doomed to collapse within the next 100 – 200 years.

    Have a nice day. 😉

  88. #88 John Bode
    October 25, 2006

    As others have mentioned, we’re working with a ridiculously small sample size; one planet out of a known few dozen that is known to have life, and one species on that planet that is known to be intelligent (by that species’ particular metrics, anyway).

    And the sample is even further biased since the history of life on Earth isn’t complete yet; who knows what will happen in the next several hundred million years? We may see multiple intelligent species arise from different lineages; we’ll probably spawn at least one or two intelligent daughter species, and I wouldn’t be surprised if that didn’t put some evolutionary pressure on other species to get smarter.

    Alternately, we may die out completely and have no other intelligent species (by our definition, anyway) take our place.

    We won’t know for sure until the Sun goes blooey (well, we won’t know either way, but someone should still be around to take notes).

    FWIW, my personal, uneducated opinion is that the Universe is lousy with life, and that the bulk of it is relatively simple (unicellular or whatever the equivalent would be on other worlds). I won’t speak to the incidence of intelligent life, but I’m fairly confident the odds of our ever encountering it are pretty damned near zero.

  89. #89 T_U_T
    October 25, 2006

    I’d bet that Erasmussimo=Erasmus, the one who tried persuade people on this blog that ballot casting has no causal effect on the outcome of an election and thus they should give up on voting, even making remarks that we ought return back to hunter-gatherer level.
    .
    So, he either genuinely hates the very idea of civilization, or he is just trolling around. The later much likely, as non-religious people with that level of mizantropism are quite rare.

  90. #90 melior
    October 25, 2006

    damian said:

    Then there is the psychological aspect of space travel. Who of us after 12 hours on a plane hasn’t been dying to get off?

    Let’s not get carried away. Many colonists were once willing to travel by sea.

  91. #91 Erasmussimo
    October 25, 2006

    T_U_T writes, “I’d bet that Erasmussimo=Erasmus, the one who tried persuade people on this blog that ballot casting has no causal effect on the outcome of an election and thus they should give up on voting, even making remarks that we ought return back to hunter-gatherer level.
    .
    So, he either genuinely hates the very idea of civilization, or he is just trolling around. The later much likely, as non-religious people with that level of mizantropism are quite rare.”

    You lose your bet, T_U_T. I have nothing to do with whomever promulgated the ideas you describe — and I don’t agree with them. Please, let’s not engage in speculative mudslinging, especially when you’re slinging mud at an innocent person!

    Best wishes

  92. #92 fred
    October 25, 2006

    After you’ve won a lottery, winning a lottery doesn’t seem unlikely. Nevertheless, a lottery win is unlikely.

  93. #93 thwaite
    October 25, 2006

    But, but: I thought it was guaranteed that someone wins the Lottery?

    Regardless, and worse, no-one is guaranteed to win the ‘became intelligent’ lottery in the exuberant, grossly excessive-to-survival way that hominids have. And even when we did, it was strictly a social intelligence for 100kyr’s, with technological and even cultural stasis simultaneously. Which argues that it arose from sexual selection, not from natural selection – i.e. that it wasn’t adaptive (and indeed human populations started burgeoning only with the invention of agriculture). More on this perspective in Geoffrey Miller’s THE MATING MIND, a cogent and seductive book.

  94. #94 jeffw
    October 25, 2006

    As others have mentioned, we’re working with a ridiculously small sample size;

    If we had just one more sample, at least we could triangulate to some degree.

    The point that PZ makes is quite valid, tho. Why isn’t ET tapping on our shoulder? Or even his AI robot scouts, or his highly-evolved technological descendents? If techno intelligence exists out there, the likelyhood of it being more advanced than we are is overwhelming, since we are infants at that game. If they exist and are nearby, they would know we are here. Therefore, they 1) are not nearby, 2) don’t wanna talk, 3) don’t exist.

  95. #95 Damien
    October 25, 2006

    > it was strictly a social intelligence for 100kyr’s

    What does that mean? We’ve been using shaped stone tools for 2.5 million years. And our tool use seems quite adaptive: we wouldn’t live without it, we’ve spread across the planet unlike any other large species, and tool use/environment manipulation in chimps and orangs is adaptive, helping them get at more food sources. Non-adaptive? Non-burgeoning populations? Pre-argricultural minds and technology colonized niches from deserts to jungles to the Arctic. What’s non-adaptive about that?

    It’s rather hard to judge cultural stasis given that we have almost no trace of the cultures. We know that existing or historical hunter-gatherer societies spanned a wide range of variation, from women’s rights or lack to number word richness or paucity, with various complex religions, and possibly the beginnings of astronomy.

  96. #96 khan
    October 25, 2006

    Somebody once said: “Every planet gets one chance.”

    I think we blew it. There will not be another technological civilization capable of leaving the planet (whether or not we are capable of such). We are burning all the fuel faster than we are inventing anything sustainable.

    Maybe that happens to all civilizations, they over breed and over consume leading to a population crash without the raw materials to ever recover beyond the neolithic (well maybe to Feudalism).

  97. #97 spidey
    October 25, 2006

    A good book on the subject is “Rare Earth” by Peter Ward and Don Brownlee.

  98. #98 thwaite
    October 25, 2006

    We’ve been using shaped stone tools for 2.5 million years. -Damien
    Yes, and as Miller points out, the initial “basic tool kit of of flakes and choppers served the needs of hunting and gathering for a million years” … a million years! Only then at 1.6mya did H. erectus introduce the handaxe – also constant for about a million years, with limited varieties (several not obviously functional, as too large/small) which can as easily be attributed to sexual display roles, Miller argues. And no handaxe is as functional as a handled blade would have been – why the prolonged lack of adaptedness?

    Hominids dispersed widely, yes – not obvious that this was dependent on tools. The population sizes were all small, and even bottlenecked well into modern humans. Post-agricultural populations are orders of magnitude larger, even with the diseases of the new dense concentrations.

    Your descriptions of cultural variability seem to draw from the near-historic experience of full humans. My (and Miller’s) perspective of cultural stasis in hominids is the million-year eras above, detailed by archaeologists such as Steven Mithen. It’s a challenge to recall how astonishingly recent full humans are, and even within that, how brief the historical (nearly synonymous with agricultural) era is.

  99. #99 Torbjörn Larsson
    October 25, 2006

    “As others have mentioned, we’re working with a ridiculously small sample size; one planet out of a known few dozen”

    Exactly my feeling, though this particular statistics is slightly wrong. Astronomers have recently released statistics on planets in a star group a fair distance away, and it confirms both that the closer observations are more general and that the tendency to a fair amount of systems that may generate earth-like planets holds. (Though again, the last is so far only supported by simulations, not observations.)

  100. #100 Chris
    October 25, 2006

    Although our evidence is obviously very limited, we do know that 100% of all known planets with life went on to develop complex multicellular life within a few billion years, 100% of those went on to develop intelligent life within a few more billion years, and 100% of intelligent lifeforms developed technological civilizations in at most a few *million* years. So saying things like “it’s very unlikely” flies in the face of the available evidence, limited though it is. There is of course a risk that Earth is not a representative sample of life-bearing worlds generally, but how can we know that until we observe at least a couple dozen others?

    Yes, *our particular history* is unlikely, but this is no more than saying that *my particular hand* of bridge is unlikely. The chance that I would be dealt some hand fairly like it may be quite large (unless I have a hand that belongs to a genuinely unlikely set, like a 10-card suit). We don’t know if it takes the equivalent of a 10-card suit (very unlikely), a 6-card suit (only modestly unlikely), a 5-card suit (most hands have one although they’re not all the same), or a 4-card suit (inevitable and it’s not even rare to have more than one).

    We don’t have enough data about evolution on other planets to say how likely any of the other steps are.

  101. #101 Ebonmuse
    October 25, 2006

    I’ve got to nitpick this, PZ:

    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.

    I hate to sound pedantic, but how do you know that intelligence only evolved once on Earth? If we were to go extinct tomorrow, how much material evidence of our civilization would we leave behind for archaeologists to discover ten or twenty million years from now? Not much, I’ll wager. Even plastic will break down on a time frame like that.

    I’m not seriously suggesting that there’s ever been another earthly species with our level of civilization, but who knows? There may have been other species in the past that developed intelligence and died out without leaving much in the way of material remains. (The Science of Discworld has fun with this concept, imagining intelligent crab and dinosaur civilizations that nevertheless didn’t make it far enough past their respective Stone Ages before being wiped out to leave archaeological evidence behind.) I’m not saying I necessarily think this is likely, but one should always be wary of arguments founded on an absence of evidence.

  102. #102 Tatarize
    October 26, 2006

    “Nothing demonstrates the improbability of the origin of high intelligence better than the millions of phyletic lineages that failed to achieve it.”

    Achieve it? As if it’s a goal? Intelligence, like most traits possessed by organisms, is an evolutionary product. I cannot, however, think why it there should be much evolutionary pressure on it for this planet or any planet which might support life. I would think being larger than other animals has saved me more times than being smarter.

    Multicellularism may also be rather rare in the universe. Also, what ever photosynthesis or chemosynthesis or unknownsynthesis used to introduce energy into the xenobiospheres of other worlds might not have such inefficencies to allow for our type of life. If plants did photosynthesis and burnt their own oxygen we’d be hard pressed to be as active as we are.

    I still think it exists somewhere, but I think our sample size is large enough to say maybe it’s not close. We can certainly rule out a zero chance (we exist, and thus all variables needed for intelligent life are non-zero). But, everything else is just guessing.

  103. #103 Keith Douglas
    October 26, 2006

    Sagan’s blunders aside, I think there are two other possibilities to consider (beyond the “they ARE here”). One is that the expense of sending generation ships really is quite prohibitive – look at us, we’re running into resource problems ourselves. Second is “the prime directive” …

    (yes, the second is somewhat tongue-in-cheek.)

    poke: China should remind us how a sudden change in policy by the powers that be can change the attitude (either way, mind you) about exploration. What if a successor to Zheng He had visited Montezuma? How would the world have been different? (We can’t know, of course, but speculation can be interesting.)

    melior: Though, a lot of colonists did it out of sheer desperation. (Parallel in some SF where people leave Earth for similar reasons; I hope we don’t repeat the idea of shipping slaves off …)

    As for the Drake equation, I have always regarded its best use as a thought experiment – to get one thinking about what is involved in extraterrestrial intelligence.

  104. #104 thwaite
    October 26, 2006

    Today’s strip in the cartoon Non sequitur is perfectly apt for this topic.

  105. #105 dzd
    October 26, 2006

    I think focusing on the capital-S Singularity as the solution to everything is pretty hilarious, especially considering that most of the interesting sf nowadays is concerned with the ways singularity-type events can be derailed or curtailed or just plain fail. Usually thanks to good old human nature.

    The machines get fancier, but the minds don’t get any more moral.

  106. #106 dzd
    October 26, 2006

    Addendum: Stross is great and all, but the world he depicts in Glasshouse isn’t a world I would want to live in, shiny technologies or not.

  107. #107 LC
    October 27, 2006

    Whether intelligent space-faring civillisations actually exist or not, I sincerely hope that we do not get visited by any for a very long time indeed. The effect on our own civillisation here would be catastrophic.

    Look at the effect Western civillisaiton has had on every ‘less-developed’ civillisaiton or social group it has ever come into contact with. Forget even the instances of violent take-over. Even when we contact more ‘primitive’ (please excuse these terms) societies with benevolent intentions, the effect our different and more technologically advanced society has on that group is almost always desructive. Native society breaks down, Our ways are perceived as more desirable than the native ways and just the knowledge that we exist destabilises that native society. Just a single gift of a metal pan or a pair of scissors makes a huge impact on a amazonian tribe’s way of life. But we regard it as unethical, or perhaps just impractical to try an observce such tribes ‘secrtetly’.

    Now imagine the tables turned. An alient race arrives in orbit and beams down. Even if its intentions are benevolent and not to take us over the impact such a different and more technologically advanced presence would have on our civillisaiton would be immense. This is even without taking account of religous people (god knows how they would react, presumably not that ‘rationally’).

    Even with good intentions, we would inevitably devalue our own achievements and it would be so easy for us to become dependent on this new technology and new ways. Their simple prsence may be enough to destabilise our society in the same way we effect amazonian tribes.

    I’m deliberately leaving out such aspects of the impact of diseases and microbes and any tempation to rule us by benevolent force. Our society naturally ‘rules over’ primitive tribes even without trying, because we are so so much more powerful technologically. Would the same thing happen to us, just by default, if a technologically superior race happened by?

    So, exciting as it would be, I hope we never get visited by any other race until we are in more of a position to meet with them as equals or near equals. And really, what is the probability of that?

  108. #108 John H. Morrison
    October 27, 2006

    There exists another possible explanation for the development of advanced intelligent life on earth only once. The first one to develop such intelligence — modern homo sapiens, our own species — during its expansion around the world killed off all other species of mankind. They also caused numerous mass extinctions of other species as well.

    In the past couple of years, there has been talk of a possible phenomena during the evolution of life that I believe would make life itself extremely rare throughout the universe.

    Why is green the color of life? Why is chlorophyll, the chemical responsible for photosynthesis, green? The sun’s spectrum of light peaks in the green, so it seems grossly inefficient for something absorbing sunlight as energy to reflect away the most intense region.

    The idea discussed is that when photosynthesis removing carbon dioxide from the atmosphere first developed, the earth nearly missed suicide in the form of a frozen snowball. If photosynthesis pulled out too much carbon dioxide from the atmosphere, the world would have become cold enough to cover the world in ice — reflecting away more sunlight and cooling down further. The end result might be 50 degrees below zero with the earth’s surface covered with ice and all life gone.

    Maybe I exaggerate. But it seems to me that normally with photosynthesis, more efficient sunlight consumption — absorption of green — would be a local evolutionary advantage, so if this led to the frozen snowball, that would be the normal consequence of life on a planet.

    Our earth therefore would have to be an enormous statistical outlier.

  109. #109 Caledonian
    October 27, 2006

    Or perhaps plants reflect the frequencies that the sun peaks in because they would overheat and fry if they absorbed too much of the light.

  110. #110 Damien
    October 27, 2006

    Thing is, plants don’t pull CO2 out of the environment for long: much is returned quickly by respiration of the plants themseles, not to mention the animals that eat them. Also, while I’m no expert on plant metabolism, from what I’ve been able to tell the rate-limiting factor on plant growth is CO2, not energy. Absorbing more light wouldn’t help them absorb more CO2 at its part per ten thousand concentrations. Photosynthesis is pretty efficient in dim light.

    Of course, there’s plent of N2 in the atmosphere; I don’t know why nitrogen-oxygen-hydrogen compounds haven’t been used for energy storage. Maybe they’re all explosive.

  111. #111 John H. Morrison
    October 27, 2006

    It seems to me that a plant that evolved pulling in much more energy would also evolve structure that would withstand that energy and not overheat or fry.

    It seems to me that water, sunlight, and nutrients in the ground, as well as the plant’s inherent structure, limit plant growth. I’ve never heard of a CO2 draught.

    The initial photosynthesizing oxygen-producing organisms were single-celled creatures, not plants. They could not have consumed oxygen themselves, because they were probably the first oxygen-producing organisms — oxygen has to be produced before it can be consumed. So most likely, the organisms did not return CO2 to the atmosphere.

  112. #112 Laura Quilter
    December 20, 2006

    a belated science fiction correction for Ritchie Annand and other readers: The ansible is not “Orson Scott Card’s” ansible; it is a convention that many sf adopt, and it was created / invented by Ursula Le Guin in 1966, in Rocannon’s World. And describes its invention in greater detail in The Dispossessed (1974).

  113. #113 giiordano bruno
    October 27, 2007

    I doubt that fleshy water diffusion intelligence would travel. Even with the atmosphere-equivalent of 10 metres of ice shielding, the time-to-decay of secondaries would fry them.
    ie you need that 10km of atmosphere to allow secondaries time to decay.
    So that leaves solid-state, ie built, not grown intelligences.
    Problem here is robot-drug-addiction. Lets say the robot has a “Travel is Good” register which keeps it on it’s merry way. Because it has its own schematic, it knows the location of the “Travel-Dispersion = pleasure” register,, so it simply sets it to “Full = happy” and ceases to travel. Humans dont have schematics (yet) so crude Morphine loading isn’t fully satisfying (ie. its boring, we need to find the “bored” register/accumulater and set it to “empty”? As Burroughs said, junkies are not interesting/interested, they sit around staring at their toes all day), and the rulers tend to throw you in prison if you use morphine every day.
    How to keep that robot traveller travelling? Wetlife loves dispersion second only to reproduction, but its just an urge/itch, which solidlife will always (?) override?

  114. #114 Arun
    November 15, 2007

    Please take a look at the argument at

    http://capitalistimperialistpig.blogspot.com/2007/11/fisking-ernst-mayr.html

    that argues that the “improbability of intelligence” argument is similar to the “improbability of self-replicating stuff arising from a chemical soup” of the creationists.

  115. #115 Arun
    November 18, 2007

    http://capitalistimperialistpig.blogspot.com/2007/11/take-that-bio-boy.html

    Reproducing the post in full:

    One clear theme of evolutionary history is the cumulative nature of biological diversity. Individual species (for nucleated organisms, at least) may come and go in geological succession, their extinctions emphasizing the fragility of populations in a world of competition and environmental change. But the history of guilds – of fundamentally distinct morphological and physiological ways of making a biological living – is one of accrual. The long view of evolution is unmistakably one of accumulations through time, governed by rules of ecosystem function.
    …………….Andrew H. Knoll in Life on a Young Planet

    That’s my answer to Ernst Mayr, Stephen Jay Gould, PZ Myers and all the other bio-boys arguments on the subject of the evolution of intelligence. The fundamental flaw in their argument is the notion that evolution isn’t going anywhere – it’s actually going everywhere, everywhere there are new energy and negative entropy sources to be exploited. Knoll has another key piece of the puzzle, too:

    Another great theme is the coevolution of Earth and life. Both organisms and environments have changed dramatically through time, and more often than not they have changed in concert. Shifts in climate, in geography, and even in the composition of the atmosphere and oceans have influenced the course of evolution, and biological innovations, in turn, affected environmental history. Indeed, the overall picture that emerges from our planet’s long histoy is one of interaction between organisms and enviroments. The evolutionary epic recorded by fossils reflects, as much as anything else, the continuing interplay between genetic possibility and ecological opportunity.

    Blindness to these key points is the crucial weakness in the arguments in against the plausibility of the evolution of intelligence, and, as I have pointed out elsewhere, is ironically just a replay of the classic creationist argument against the spontaneous origin of life.

    Big, complex, eukaryotic cells could not evolve until our bacterial cousins had learned how to use photosynthesis to transform the chemistry of the world. It took them a long time, because it’s hard, and the world is big. The long time it took is not a good argument in favor of it being unlikely – the bank robber robbed the bank because that was where the money was, and cells learn photosynthesis because that’s where the negative entropy is. Students of Mayr should note that I’m using “why” in the teleonomic rather than teleological sense here.

    Similarly, multicellularity couldn’t evolve without big, complex cells to build it out of. Nor could anything like intelligence evolve until a sophisticated muscular and sensing system had preceeded it – those things and an environment in which it could be useful. So why didn’t high intelligence evolve in the Mesozoic or even in the Permian? I don’t know, of course, but it certainly looks like a reasonable guess that the suitable prerequisites both environmental and organismic, had not yet accrued.

    Failure to recognize the fact and importance of accrual is linked to another failure of Mayr and his party – excessive focus on the organism rather than the gene. Focus on the organism misses most of cumulative character of evolutionary change. Organisms come and go, but the ways of making a living encoded by their genes tend to survive, if they are useful enough to their possessors.

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