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Thread: Study says we are probably alone in the universe

  1. #1
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    Study says we are probably alone in the universe

    This is totally silly, I find. Come on!

    When the model is recast to represent realistic distributions of uncertainty, they find a substantial probability of there being no other intelligent life in our observable universe
    https://www.nextbigfuture.com/2018/0...-universe.html

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    Quote Originally Posted by gzhpcu View Post
    This is totally silly, I find. Come on!



    https://www.nextbigfuture.com/2018/0...-universe.html
    agreed! probabilities of unknowns is an angels dancing on pins game. I like the "either we are or we aren't, so that's 50/50" argument. And whether being alone means we have to try to get to other stars as opposed perhaps to doing that to meet others, is an odd kind of argument. I wonder if the explorers of oceans thought "we will only do this because we might be alone on this planet"?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Correct me if I am wrong, but doesn't the Monte Carlo method take a sample of what you do have and generates a set of probabilities? You have example of life and then a lot of examples of no life... doesn't that require that all outcomes sum to one or less? It seems like a poor way to determine if there is more than one example.

    "There is an elephant in England... What is the likelihood of having two elephants in England?" That isn't a logic/math thing because elephants in England do exist, but has nothing to do with logical choices.

    I will accept the challenge that a great number of places look bad for life, and still want to think that life is possible. It's an opinion, a hunch. I'm not going to play the game the other direction based on logical rigor.
    Solfe

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    Itís kind of hard to extrapolate from one datum. Itís also easy to match a model to a single datum. I think itís valid to place limits on where known biochemistry can function, hence the rather restricted definition of ďhabitable zone,Ē but itís premature to conclude either Earth is uniquely a location for life or terrestrial biochemistry is the only possible type. It is possible to make premature conclusions.
    Last edited by swampyankee; 2018-Jul-02 at 12:09 PM.

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  5. #5
    This kind of stuff is where math and philosophy collide.
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    Quote Originally Posted by swampyankee View Post
    It’s kind of hard to extrapolate from one datum.
    I would say it is entirely too easy to extrapolate from one data point... in fact, there are an infinite number of extrapolations. The hard part is knowing which one is the right one.
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    Quote Originally Posted by Solfe View Post
    Correct me if I am wrong, but doesn't the Monte Carlo method take a sample of what you do have and generates a set of probabilities? You have example of life and then a lot of examples of no life... doesn't that require that all outcomes sum to one or less? It seems like a poor way to determine if there is more than one example.

    "There is an elephant in England... What is the likelihood of having two elephants in England?" That isn't a logic/math thing because elephants in England do exist, but has nothing to do with logical choices.

    I will accept the challenge that a great number of places look bad for life, and still want to think that life is possible. It's an opinion, a hunch. I'm not going to play the game the other direction based on logical rigor.
    The Monte Carlo method uses probability distributions for each factor in the equation.

    You fire say 10,000 trials through the series of probability distributions (nine in this case) and see where they end up. You end up with a product distribution.

    If many of the individual distributions are not Normal, but instead heavily weighted towards the very unlikely end, it is easy to see the average final probability could end up very low. So it doesn't seem too unreasonable to me.

  9. #9
    The problem is we have no data on some of factors so we really can't tell what is out there. Math needs experimental evidence to back it up. You can theorize anything without evidence.
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    I am so old that the Monte Carlo method has evolved and become statistical thanks to computers. a couple of centuries ago I used to conduct brainstorming sessions professionally and we used to a Monte Carlo estimation (we did call it that) as warm up exercise. It involved asking each member of the team to guess a value for some number they probably did not know, and then calculating the average. The high and low outliers then were allowed to change their estimate in any direction they chose. The final result was then compared to a value previously researched. In every case I remember the result was strikingly good, within 5% usually. So in this example of a rather meaningless probability one could do the same but unfortunately there is no right answer with which to compare.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  11. #11
    The problem with some mathematicians is that they got too much into being clever with the math and don't factor in the real world and make models that really beautiful but can't be tested and therefore not science. [cough] string theory[/cough]
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    Quote Originally Posted by kzb View Post
    The Monte Carlo method uses probability distributions for each factor in the equation.

    You fire say 10,000 trials through the series of probability distributions (nine in this case) and see where they end up. You end up with a product distribution.

    If many of the individual distributions are not Normal, but instead heavily weighted towards the very unlikely end, it is easy to see the average final probability could end up very low. So it doesn't seem too unreasonable to me.
    There's no link to the paper. But since I caught it last week when Universe Today published a similar article, with references, I have read the paper itself. I guess I get it, but I don't like how this article on the paper was written. Too many deets left out.
    Solfe

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    Quote Originally Posted by kzb View Post
    ... If many of the individual distributions are not Normal, but instead heavily weighted towards the very unlikely end, it is easy to see the average final probability could end up very low. So it doesn't seem too unreasonable to me.
    However, then the central limit theorem kicks in:
    In probability theory, the central limit theorem (CLT) establishes that, in some situations, when independent random variables are added, their properly normalized sum tends toward a normal distribution (informally a "bell curve") even if the original variables themselves are not normally distributed. The theorem is a key concept in probability theory because it implies that probabilistic and statistical methods that work for normal distributions can be applicable to many problems involving other types of distributions.

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    Study says we are probably alone in the universe

    So the study is saying that we're probably not being studied, good to know ;-)

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    Quote Originally Posted by Swift View Post
    I would say it is entirely too easy to extrapolate from one data point... in fact, there are an infinite number of extrapolations. The hard part is knowing which one is the right one.
    Well, to extrapolate meaningfully. After all, Lord Kelvin extrapolated from too little data and determined heavier-than-air flight wasn't possible.
    Last edited by swampyankee; 2018-Jul-02 at 10:27 PM.

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    Quote Originally Posted by Selfsim View Post
    However, then the central limit theorem kicks in:
    Yes absolutely. With nine distributions combined it's likely the resultant distribution is close to Gaussian.

    The issue is what is the mean and what is the size of the standard deviation?

    If you have many contributing distributions which are heavily weighted to small probabilities, that will bring down the mean of the resultant distribution.

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    I think it remains both funny and serious misapplication of statistics. It is like assigning a probability to anything you can imagine but have no consensual evidence for, like dragons, fairies, universes that existed before the big bang. It is not really the same as using the evidence of planets around stars to guess at the chances of life there, although using the zero case is useful in some examples like what is the chance in a group of at least two people having the same birthday. You work out the chance of none first. But there you have solid numbers to work with.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Silly and arrogant because we know so little about life and the universe. We estimate currently 10 to the power of 24 stars. We alone? Make me laugh.

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    Quote Originally Posted by gzhpcu View Post
    Silly and arrogant because we know so little about life and the universe. We estimate currently 10 to the power of 24 stars. We alone? Make me laugh.
    now it's my turn to disagree, we don't know, so a value to a probability is silly, but it's possible we are alone, but then there are those multiverse ideas, which Hawking's last paper addresses with the theoretical possibility of gravity wave testing, or was it neutrino flux testing, anyway, testing. so for the moment we are alone in the everyday alien sense with no idea if that will change or when.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    If you were a biologist, and were sent to Australia, to study the kangaroos, would you have lunch and chat with them?

    pete

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    Quote Originally Posted by trinitree88 View Post
    If you were a biologist, and were sent to Australia, to study the kangaroos, would you have lunch and chat with them?

    pete
    It would depend how many white russians the Kangaroos can take before they drop their guard, how is that relevant, no matter, it's a good question, did i give the right answer?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Pro, just because you didn't get it, doesn't mean Trinitree's statement was irrelevant.

    Biologists try not to interfere too heavily when doing field studies.
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    Quote Originally Posted by BigDon View Post
    Pro, just because you didn't get it, doesn't mean Trinitree's statement was irrelevant.

    Biologists try not to interfere too heavily when doing field studies.
    No you are right but i am still baffled, maybe i must go back a few posts, is this about being alone in the universe?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    I recommend you read the paper,
    https://arxiv.org/pdf/1806.02404.pdf
    or at least the commentary by Anders Sandberg
    http://aleph.se/andart2/space/seti/d...fermi-paradox/
    This paper is just a statistical analysis of various estimates of probability by a large number of authors, and seems to show that there is a good chance that aliens are rare or very rare, while preserving the possibility that aliens are common.
    It also shows that estimates that are likely biased towards optimism (because of publication bias) can be used to get a credence distribution that dissolves the paradox once they are interpreted as ranges. See the above figure, where we get about 30% chance of being alone in the Milky Way and 8% chance of being alone in the visible universe… but a mean corresponding to 27 million civilisations in the galaxy and a median of about a hundred.

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    Quote Originally Posted by profloater View Post
    No you are right but i am still baffled, maybe i must go back a few posts, is this about being alone in the universe?
    Yes,

    He was stating we shouldn't be able to tell one way or the other, if the aliens are doing their studies correctly.
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    Personally, I see the study as an attempt at reminding professionals and amateurs of how we've allowed our speculations to stand in the way of the fact that the state of whatever the answer to the question about life elsewhere is, remains firmly as being: 'unknown'.

    No matter how much we'd like to think of science (and statistics) as revealing undiscovered 'truths', the fact is that science directed at philosophical pursuits - in particular: 'truth' about life eleswhere, drags it away from its reputation of being useful to our immediate, hence observable, circumstances.
    IMO.

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    Quote Originally Posted by eburacum45 View Post
    I recommend you read the paper,
    https://arxiv.org/pdf/1806.02404.pdf
    or at least the commentary by Anders Sandberg
    http://aleph.se/andart2/space/seti/d...fermi-paradox/
    This paper is just a statistical analysis of various estimates of probability by a large number of authors, and seems to show that there is a good chance that aliens are rare or very rare, while preserving the possibility that aliens are common.
    So there is a chance that aliens are common, and a chance that they are very rare.
    Well, that really answers the question!
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

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    Quote Originally Posted by gzhpcu View Post
    Silly and arrogant because we know so little about life and the universe. We estimate currently 10 to the power of 24 stars. We alone? Make me laugh.
    It's also silly and arrogant to assume we AREN'T alone just because you disagree with the statistics. Want to make ME laugh? Tell me your definition or prerequisites of what DOESN'T make us alone.

  29. #29
    All most of are saying is that we don't have enough data to base the statistics to be real.
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    Quote Originally Posted by Exposed View Post
    It's also silly and arrogant to assume we AREN'T alone just because you disagree with the statistics. Want to make ME laugh? Tell me your definition or prerequisites of what DOESN'T make us alone.
    just look at the immensity of the universe and there is your answer. Plus look at our at our puny brains. You have it all wrong: arrogance is to say we are alone in the universe.
    Last edited by gzhpcu; 2018-Jul-04 at 08:12 PM.

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