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Thread: aliens will look like humans

  1. #1
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    aliens will look like humans

    http://www.independent.co.uk/news/sc...-10358164.html


    "The author said extra-terrestrials that resemble human beings should have evolved on some of the many Earth-like planets that have been discovered"

    The comments are very interesting, and seem to be made by learned men&women.

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    Quote Originally Posted by Gomar View Post
    ...seem to be made by learned men&women.
    Appeal to authority.

    "The author said extra-terrestrials that resemble human beings should have evolved on some of the many Earth-like planets that have been discovered"
    Bunkum. He's selling a book, nothing more. Even superficially similar parallel evolution doesn't produce copies. Sharks and dolphins are both vertebrates in similar niches, and are roughly similar in shape, but are still anatomically and physiologically very different in all details. Octopuses have eyes not-really-very-like ours and even share half of our DNA but otherwise are totally different, enough to be considered "alien".
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    Not sure about the premise that advanced life necessarily is going to be humanoid-ish. Had various extinctions, climate changes, continental drifts not taken place then humans probably would not have evolved. Its a fun idea and sort of convenient if we can come across similar biology to our own but sounds like a sci fi novel.

    For all we know, had humans not evolved, maybe dolphins would have become more advanced....or say had the seas started drying up some freak dolphin mutation walks out of the sea and starts living on the land, and in 100k years they are landing on the moon ;-)

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    To add to what Noclevername and Jetlack said... though an exoplanet may be "Earth-like", unless it is an identical copy it will almost certainly have different surface gravity, differences in atmospheric composition and pressure, differences in elemental abundance, differences in the intensity and spectrum of light from its star, etc., etc., and these differences will have to have significant impacts on the life that evolves on that world.

    And what exactly does "look like humans" mean. To me, the so-called little green aliens with the big heads and eyes do look like humans (arms, legs, bilateral symmetry, etc.). I'd personally be surprised if real aliens look that much like us, but that's the author's example of looking different. Puppeteers or Thranx or Fithp seem as possible a shape as humans, but certainly don't look like humans.
    Last edited by Swift; 2015-Sep-25 at 07:10 PM.
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    Quote Originally Posted by Swift View Post
    Puppeteers or Thranx or Fithp seem as possible a shape as humans, but certainly don't look like humans.
    And even Puppeteers and fithp, while not necessarily human, are still pretty mammalian. And Thranx are insectoid.

    I think there are shapes where we will just as likely have a tough time telling one end from the other.

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    Quote Originally Posted by Swift View Post
    To add to what Noclevername and Jetlack said... though an exoplanet may be "Earth-like", unless it is an identical copy it will almost certainly have different surface gravity, differences in atmospheric composition and pressure, differences in elemental abundance, differences in the intensity and spectrum of light from its star, etc., etc., and these differences will have to have significant impacts on the life that evolves on that world.

    And what exactly does "look like humans" mean. To me, the so-called little green aliens with the big heads and eyes do look like humans (arms, legs, bilateral symmetry, etc.). I'd personally be surprised if real aliens look that much like us, but that's the author's example of looking different.
    Yes... Though I wonder whether the first few lines of the article are a fair representation of Conway Morris' new book, or whether they are an opinion of the journalist Paul Gallagher, based on an exaggerated and simplified understanding of Morris' argument.

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    Accepting the convergence argument up to a point, intelligent, tool-using aliens might look quite human-like in certain respects but in other respects not.

    E.g. Perhaps like us they have a torso (containing organs which process nutrients and nutrient gases) and a head with sense organs, a mouth, and something inside for processing information... but they have organs of manipulation which proceed from the head rather than the body? Like an elephant's trunk, or an octopus's tentacles...

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    Quote Originally Posted by Colin Robinson View Post
    E.g. Perhaps like us they have a torso (containing organs which process nutrients and nutrient gases) and a head with sense organs, a mouth, and something inside for processing information... but they have organs of manipulation which proceed from the head rather than the body? Like an elephant's trunk, or an octopus's tentacles...
    Then they'd really be living hand-to-mouth.

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    I sort of hope they look like giraffes.
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    Quote Originally Posted by Noclevername View Post
    Then they'd really be living hand-to-mouth.

    Or at least they evolved from something that did... Isn't that the way it is, with animals in the wild?

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    Quote Originally Posted by Buttercup View Post
    I sort of hope they look like giraffes.
    The combination of chance and convergence might make them look like a mixture of earth animals. In the same way that a platypus looks like a mixture of a duck and a mole.
    Last edited by Colin Robinson; 2015-Sep-25 at 09:29 PM.

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    It is my opinion that, whatever shape they take, they won't look alien enough.

    Humans have a proclivity for finding patterns in things, especially finding human shapes. I predict that aliens will have some discrete element that will look similar enough to something human-like that we will be incapable of not making the connection.

    They'll look like huge buttocks on legs, or the pattern on their carapaces will look like a giant smiley face, or they'll have a phallic protrusion emanating from their forehead.

    Movie depictions of aliens have to avoid these things because fiction is constrained by the need to be believable, whereas reality has no such constraint.

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    If the dinosaurs hadn't gone extinct maybe we'd all be Gorns typing here today speculating that aliens would appear lizard-like?

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    Quote Originally Posted by Noclevername View Post
    Appeal to authority.



    Bunkum. He's selling a book, nothing more. Even superficially similar parallel evolution doesn't produce copies. Sharks and dolphins are both vertebrates in similar niches, and are roughly similar in shape, but are still anatomically and physiologically very different in all details. Octopuses have eyes not-really-very-like ours and even share half of our DNA but otherwise are totally different, enough to be considered "alien".
    Simon Conway Morris is an authority on evolutionary theory -- he's a professor of paleobiology at Cambridge -- and he's presenting conclusions in evolutionary theory, so he is a legitimate authority on the topic, so he is the sort of authority to whom it is appropriate to appeal, just as it's legitimate to use Kip Thorne as an authority on gravitational theory. This sort of convergence just so happens to be part of a position he has held for years, which is (if I remember and interpret this correctly) that the general layout of organisms that occupy specific niches are sufficiently close to the optimum that they are nearly inevitable: a different creature occupying the niche of "land-dwelling intelligent animal*" will be four-limbed, with a distinct head, and dedicated mobility and manipulatory appendages: that shape is optimal for the niche, just as a fusiform shape with a single, crescent-shaped propulsive tail and a small number of stabilizing limbs is optimal for marine predators.

    As for selling books? I'm presuming that's not some sort of accusation, because touting books is something just about every author does. Certainly, Neil deGrasse Tyson hasn't emulated JD Salinger and eschewed all publicity.

    Note that I'm not saying that I agree with Conway Morris (I don't), but "appeal to authority" is not always a logical fallacy: using NdeGT to support the position that Pluto should be a dwarf planet or Kip Thorne that closed time-like curves are permitted under general relativity are not logical fallacies. It is possible to cherry pick an authorities position, however, but this is a different logical fallacy.


    Skipping past that pedantry, do I think that Conway Morris' prediction is likely to be true? No. Could I present a reasoned, academically valid argument against it? No, but this is because I think evolution, that is somewhat random variation with natural selection, is the sort of optimization process that is prone to finding false optima -- a random event (like a meteor hitting roughly were the Yucatan is today) can push the "evolutionary optimizer" to a different "best" by eliminating swaths of variation.
    Last edited by swampyankee; 2015-Sep-26 at 03:32 PM.
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    Quote Originally Posted by swampyankee View Post
    Simon Conway Morris is an authority on evolutionary theory -- he's a professor of paleobiology at Cambridge -- and he's presenting conclusions in evolutionary theory, so he is a legitimate authority on the topic, so he is the sort of authority to whom it is appropriate to appeal, just as it's legitimate to use Kip Thorne as an authority on gravitational theory.
    Missed my point. I was referring to the comments that Gomar talked about. Not the author.

    As for selling books, it means Morris has a money motive for pushing his ideas. All authors sell books, but most sold books (including this one) do not get peer reviewed and contain scientifically gathered data.
    Last edited by Noclevername; 2015-Sep-26 at 04:00 PM.
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    Galen, Aristotle, and other classical sources were authorities, yet their theories were still wrong. Einstein was brilliant, yet he rejected Quantum Mechanics. Authority does not make one right. Every hypothesis stands or falls on its own merits.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Conway Morris' work on the Burgess Shale was excellent. I am, however, absolutely flabbergasted that anyone could work with the bizarre species in the Burgess Shale (Anomalocaris? Opabinia? Hallucigenia?) and expect that alien life would resemble life on Earth.

    My goodness, life on Earth doesn't even resemble life on Earth if you go back far enough.

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    Quote Originally Posted by eburacum45 View Post
    I am, however, absolutely flabbergasted that anyone could work with the bizarre species in the Burgess Shale (Anomalocaris? Opabinia? Hallucigenia?) and expect that alien life would resemble life on Earth.

    My goodness, life on Earth doesn't even resemble life on Earth if you go back far enough.
    Excellent point. A point Stephen J. Gould made often in his books. Rewind Earth's biosystem a billion years and then play again, and we would get utterly different results. The Precambrian explosion resulted in a plethora of body forms, nothing like we see today. Almost all of them died off, leaving just the few from which virtually all modern life evolved. Imagine lifeforms with 20-fold symmetry.

    (I am very familiar with Anomalocaris, Opabinia Halligenia, Wiwaxia, et al. My sister is the artist known as the Queen of the Burgess Shale. If you Google any of these names, the images you see were probably originally envisioned and reconstructed by her, in direct consultation with the scientists.)

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    Quote Originally Posted by Noclevername View Post
    Missed my point. I was referring to the comments that Gomar talked about. Not the author.

    As for selling books, it means Morris has a money motive for pushing his ideas. All authors sell books, but most sold books (including this one) do not get peer reviewed and contain scientifically gathered data.
    Oh, I think Gomar cherry-picked what Conway Morris has said, which is a different logical fallacy. I also think Conway Morris is wrong, mostly because I have experience with various software optimizers, which are carefully designed to avoid false optima, and don't. I know it's a flawed analogy, but any optimization process, whether a designed system like Copes ConMin, genetic algorithms, or an undesigned one, like natural evolution, is sensitive to initial conditions and the scoring method.

    As for the fallability of authority? True; the realm in which any authority is competent is finite and changes with time, and even within nominal areas of expertise, experts err. Lord Kelvin was certainly a great scientist; he didn't exactly get it right about aircraft, and would probably been a bit less definitive had he paid attention to Hiram Maxim, who got an aircraft aloft in 1894.
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    To me this hinges on what you mean by similar. Somebody mentioned dolphins and sharks, saying that they are different. It's certainly true that a dolphin moves its flippers up and down whereas a shark moves its fins from side to side, but they both developed essentially the same means of propulsion.
    As above, so below

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    I once saw a paleontologist quoted as saying that a centaur-like creature should be seriously considered as a viable possibility on other planets. That would give sturdy quadruped support along with a free pair of limbs for handling things the way we do with our hands and arms. Our biped nature is by no means ideal or perfect. It is an adaptation of four-limbed anatomy that is adequate for survival.

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    Of course, evolution has to work with small increments, all of which must work, and tends not to recover solutions lost in a given line.
    Information about American English usage here and here. Floating point issues? Please read this before posting.

    How do things fly? This explains it all.

    Actually they can't: "Heavier-than-air flying machines are impossible." - Lord Kelvin, president, Royal Society, 1895.



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    Quote Originally Posted by Hornblower View Post
    I once saw a paleontologist quoted as saying that a centaur-like creature should be seriously considered as a viable possibility on other planets. That would give sturdy quadruped support along with a free pair of limbs for handling things the way we do with our hands and arms. Our biped nature is by no means ideal or perfect. It is an adaptation of four-limbed anatomy that is adequate for survival.
    Yes a creature that could run fast on all fours and then with a pair of hands would be a match for us and probably out-compete us. I hope we never come across it ;-)

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    Quote Originally Posted by Jetlack View Post
    Yes a creature that could run fast on all fours and then with a pair of hands would be a match for us and probably out-compete us. I hope we never come across it ;-)
    Not something I would worry about. Today we are seriously threatening some of the most powerful animals on earth--tigers, elephants, rhinos, great whites. Being able to outrun us is no good anymore because we have M16s and cruise missiles if the M16s fail. The issue with a centaur would be how we would treat them legally. If we accepted them as human, then they would dominate the summer Olympics, but not the parallel bars!
    As above, so below

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    Quote Originally Posted by Jens View Post
    Not something I would worry about. Today we are seriously threatening some of the most powerful animals on earth--tigers, elephants, rhinos, great whites. Being able to outrun us is no good anymore because we have M16s and cruise missiles if the M16s fail. The issue with a centaur would be how we would treat them legally. If we accepted them as human, then they would dominate the summer Olympics, but not the parallel bars!
    Yes itīs a shame we are devastating so much wildlife. Our record is not good so far. Hopefully we sort things out before its all too late.

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    Quote Originally Posted by Hornblower View Post
    I once saw a paleontologist quoted as saying that a centaur-like creature should be seriously considered as a viable possibility on other planets. That would give sturdy quadruped support along with a free pair of limbs for handling things the way we do with our hands and arms. Our biped nature is by no means ideal or perfect. It is an adaptation of four-limbed anatomy that is adequate for survival.
    What would their ancestors have been doing with the extra limbs before inventing technology?

    Quote Originally Posted by eburacum45 View Post
    I am, however, absolutely flabbergasted that anyone could work with the bizarre species in the Burgess Shale (Anomalocaris? Opabinia? Hallucigenia?) and expect that alien life would resemble life on Earth.

    My goodness, life on Earth doesn't even resemble life on Earth if you go back far enough.
    For the purposes of this particular claim, the Burgess Shale demonstrates the point perfectly with its consistent internal similarities. No matter how wildly different we might think things look in certain ways, all animals that move around much are still variations on a single theme: everybody has symmetrical left & right sides, with limbs paired if they're present at all, and a head in front... and it's particularly important that, even if bilateral symmetry only originated once (unknown), various lineages came up with different ways of assembling a head from the available parts. That already covers the first few steps of getting to a technology-building critter with pairs of limbs and a head on top.

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    Quote Originally Posted by Delvo View Post
    What would their ancestors have been doing with the extra limbs before inventing technology?
    Picking berries from trees? Strangling prey? Removing parasites?

    Quote Originally Posted by Delvo View Post
    For the purposes of this particular claim, the Burgess Shale demonstrates the point perfectly with its consistent internal similarities. No matter how wildly different we might think things look in certain ways, all animals that move around much are still variations on a single theme: everybody has symmetrical left & right sides, with limbs paired if they're present at all, and a head in front... and it's particularly important that, even if bilateral symmetry only originated once (unknown), various lineages came up with different ways of assembling a head from the available parts. That already covers the first few steps of getting to a technology-building critter with pairs of limbs and a head on top.
    I'm not sure if you're asserting that life is exclusively bilateral. Many critters today do not have bilateral symmetry. And I don't think five-fold, ten fold or n-fold symmetry precludes the evolution of intelligence.
    Last edited by DaveC426913; 2015-Sep-28 at 12:27 AM.

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    Quote Originally Posted by Hornblower View Post
    I once saw a paleontologist quoted as saying that a centaur-like creature should be seriously considered as a viable possibility on other planets. That would give sturdy quadruped support along with a free pair of limbs for handling things the way we do with our hands and arms. Our biped nature is by no means ideal or perfect. It is an adaptation of four-limbed anatomy that is adequate for survival.
    That's a kind of silly reasoning on the part of the paleontologist.

    If nature used a drafting board (i.e. designing with intent), there are an infinite number of ways she could make an ideal body form. It is an utterly open-ended - and equally useless - line of thought to try to consider what evolution could do.

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    Quote Originally Posted by DaveC426913 View Post
    Picking berries from trees? Strangling prey? Removing parasites?
    Perhaps a centaur-like species could evolve from an elephant-like quadruped with two trunks instead of one? (I don't mean they'd be likely to look very much like either classical centaurs or elephants. But the case of the elephant shows that a ground-dwelling quadruped doesn't need to be technological to have things to do with the functional equivalent of an arm.)

    I'm not sure if you're asserting that life is exclusively bilateral. Many critters today do not have bilateral symmetry. And I don't think five-fold, ten fold or n-fold symmetry precludes the evolution of intelligence.
    A lot of life on Earth isn't bilaterally symmetrical, but among multi-celled animals (metazoa), most groups are bilateral, and this includes diverse groups of active animals such as insects, cephalopods, and vertebrates... Living things which are not bilaterally symmetrical generally move about more slowly (or are sessile), and the sensory equipment and nervous systems are simpler.

    I think there is a valid argument that intelligent aliens would be bilaterally symmetrical too, and would resemble us in other ways, like having a specialised organ for processing sensory information (brain), and another for circulating fluids thru the body (heart)...

    On the other hand, I think the chances are against close resemblance to any single species or order of Earth life. I doubt they'd look like little green men, and I think it is equally unlikely that they would look very similar to a cat, a bear, an elephant or a turtle, or for that matter a beetle or octopus; although they might have features in common with several or all of the above.
    Last edited by Colin Robinson; 2015-Sep-28 at 02:15 AM.

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    Quote Originally Posted by Colin Robinson View Post


    I think there is a valid argument that intelligent aliens would be bilaterally symmetrical too,
    Why? What is the basis of the argument?

    Quote Originally Posted by Colin Robinson View Post
    Living things which are not bilaterally symmetrical generally move about more slowly (or are sessile), and the sensory equipment and nervous systems are simpler.
    Are you suggesting correlation implies causation, and is extrapolatable to exolife?
    Last edited by DaveC426913; 2015-Sep-28 at 02:47 AM.

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