# Basis of science's belief that extraterrestrial life is likely? **URL:** \ **Category:** Great Debates\ **Created:** [November 10, 2010, 3:43am UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137 "2010-11-10T03:43:11Z")\ **Posts on this page:** 20\ **Page:** 5
**Author:** ![Baboonanza](https://avatars.discourse-cdn.com/v4/letter/b/f475e1/32.png) [@Baboonanza](https://boards.straightdope.com/u/Baboonanza)\ **Post date:** [November 10, 2010, 12:38pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/81 "2010-11-10T12:38:42Z")
> [@Blake](#): > > Since you have facts that tell you that the conditions for life to arise are prevalent in the universe, you must be able to tell us what those conditions are. So go on, tell us what they are, and then I will dig out the references that ague exactly the opposite. We know it arose on Earth. My point is that unless you show that something spectacularly unlikely happened here to make the conditions different from the rest of the universe then the unavoidable conclusion is that they must exists somewhere else also. Is that a claim you are making? > [@](#): > > Since you have rehashed the same tired nonsense that I have already falsified, and made the same baseless claims that you can calculate the probabilities it seems pretty damn clear that you have either not read my argument or been unable to understand it. > > I repeat: If you have anything new to add i will address that, but I won’t bother addressing points that I have already falsified. You haven’t ‘falsified’ anything because there is very little in this whole debate that is anything other than groundless conjecture. We are arguing likelyhoods based on unknown variables. You have been making your own baseless claims and expecting us to accept them as fact while heaping contempt on any argument put against you. The problem with your argument is that it _requires_ life to be astonishingly unlikely. Like really, really, really, really, really unlikely. Anthing other than a once-in-a-universe chance and life will occur twice. But there is no more proof of that than there is proof that life happens everywhere. ---
**Author:** ![wintertime](https://avatars.discourse-cdn.com/v4/letter/w/c68b51/32.png) [@wintertime](https://boards.straightdope.com/u/wintertime)\ **Post date:** [November 10, 2010, 12:39pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/82 "2010-11-10T12:39:16Z")
I think one of the problems in the debate is a mix up of plausible and probable. We have become accustomed to the idea that life does exist outside our world: by fiction as well as the discussions in science. And the existence of life on earth even in environments that are extremely hostile add to the plausibility of the existence of life out there. But plausibility isn’t another word for probability - and if I understand Blake correctly he targets the later one and the tendency to assume knowledge of its numbers if we don’t even have identified the fundamentals that lead to any viable computation. ---
**Author:** ![Baboonanza](https://avatars.discourse-cdn.com/v4/letter/b/f475e1/32.png) [@Baboonanza](https://boards.straightdope.com/u/Baboonanza)\ **Post date:** [November 10, 2010, 12:48pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/83 "2010-11-10T12:48:37Z")
But then what’s the point of the debate? Nobody here is going to say they know with any accuracy the probabilies involved. Beyond saying that life occuring is a non-zero chance there is no way of determining them. Even if you knew for certain how life started it wouldn’t change anything because we don’t know for certain whether those conditions exist elsewhere. It simply seems logical to me to assume that since it’s a given that there is a non-zero chance of life occurring and that there isn’t anything obviously exceptional about Earth that the universe is big enough for it happen twice. There is no proof that life is so unlikely that it would only happen once. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [November 10, 2010, 12:51pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/84 "2010-11-10T12:51:42Z")
> [@Cheesesteak](#): > > The fact that the Earth is the only planet we know of with life does not prevent us from studying the nature of life, and developing a sense of whether or not the Earth is unique. A sense? Sure. A scientific basis? No. > [@](#): > > The point is not that we have enough information today, but that you seem to think it’s impossible to study the topic and form a reasonable hypothesis without sampling other planets. Utter, baseless nonsense. I have said repeatedly and bluntly that we have formed multiple hypotheses. Many of them mutually contradictory. > [@](#): > > If the question is “does extraterrestrial life exist?” then I only need one other planet with life to answer it conclusively. Correct. > [@](#): > > Your opinion seems to be that if we haven’t actually discovered another planet with life on it, it is impossible to even guess if there is other life out there. No, you can guess, just as you can guess whether the first aliens we meet will have gills or wings. We have absolutely no way of \*justifying \*the answers from either of those guesses, but we can certainly make the guess. I guess wings. Am I right? ---
**Author:** ![Baboonanza](https://avatars.discourse-cdn.com/v4/letter/b/f475e1/32.png) [@Baboonanza](https://boards.straightdope.com/u/Baboonanza)\ **Post date:** [November 10, 2010, 12:57pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/85 "2010-11-10T12:57:47Z")
> [@Blake](#): > > I guess wings. Am I right? Maybe! ---
**Author:** ![wintertime](https://avatars.discourse-cdn.com/v4/letter/w/c68b51/32.png) [@wintertime](https://boards.straightdope.com/u/wintertime)\ **Post date:** [November 10, 2010, 12:58pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/86 "2010-11-10T12:58:58Z")
> [@Baboonanza](#): > > But then what’s the point of the debate? I think, it’s far more productive for us to assume that life may exist than to do the opposite, because then we do actually search for it and by doing so understand life, the universe, everything better than by accepting its non-occurrence. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [November 10, 2010, 12:59pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/87 "2010-11-10T12:59:10Z")
[quote=“Baboonanza, post:81, topic:560137”] We know it arose on Earth. My point is that unless you show that something spectacularly unlikely happened here to make the conditions different from the rest of the universe then the unavoidable conclusion is that they must exists somewhere else also.[/quyote] I won’t bother to rehash the long and detailed reply that I gave to this silliness _in the OP_. I wil simply give it the consideration it deserves: This statement of your is absolute, ignorant bollocks without an ounce of support. > [@](#): > > You have been making your own baseless claims// Cite or STFU. > [@](#): > > The problem with your argument is that it _requires_ life to be astonishingly unlikely. As I said _in the fricken’ OP,_ my argument is that the probability of extraterrestrial life may be as high as 1 (absolute certainty) or as low as 1/10^87. Baboonanza, it is blatantly clear that you have been either unwilling to read or unable to understand what is clearly written in the OP. All you are doing is throwing up the same tired old dross. You have also refused to answer questions put to you, or to provide references when asked. I honestly can’t see any point in engaging you further. When you have read at least the OP, and when you have something to add that hasn’t been done to death, and when you have the courtesy to respond to questions, then you may be worth my time. Until then, have a good life. ---
**Author:** ![Baboonanza](https://avatars.discourse-cdn.com/v4/letter/b/f475e1/32.png) [@Baboonanza](https://boards.straightdope.com/u/Baboonanza)\ **Post date:** [November 10, 2010, 1:06pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/88 "2010-11-10T13:06:35Z")
Christ, there’s no need to be rude. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [November 10, 2010, 1:12pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/89 "2010-11-10T13:12:57Z")
> [@Baboonanza](#): > > Nobody here is going to say they know with any accuracy the probabilies involved. Beyond saying that life occuring is a non-zero chance there is no way of determining them. Well yeah, people are saying that they know the probabilities involved with some quantifiable precision. Multiple people, **including you** , have told us that you can calculate the probabilities and weight them in favour of one response of the other. The problem is that every time we ask you to show us how you quantified these probabilities and thus weighted them, you refuse ti answer. > [@](#): > > Even if you knew for certain how life started it wouldn’t change anything because we don’t know for certain whether those conditions exist elsewhere. > . WTF??? You just told us that you have facts that tell you that the conditions for life to arise are \*\*prevalent \*\*in the universe. Now you tell us that you can’t even know for certain that those conditions **even exist** anywhere else in the universe. Let me highlight this: First post: you have facts that tell you that **the conditions for life to arise are prevalent in the universe** This post: there is no certainty, **the conditions for life to arise might not even exist in the universe**. Are you drinking. Don’t bother to answer that. ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [November 10, 2010, 1:16pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/90 "2010-11-10T13:16:48Z")
> [@Whack-a-Mole](#): > > Dodge. > > Yet again. > > People place bets all the time. > > You have two choices: > > 1. No life in the universe except for earth > > 2. Life on a planet other than the earth > Simple really and a reasonable question. I am asking for your opinion. No bullshit about, “It is unknowable!” A dice roll in Vegas is unknowable too…people still bet on it. They _choose_ to. And usually they imagine they have some notion of their chances. > [@](#): > > The hypothetical did not demand you know the odds. It is an all or nothing deal. Double your money or lose everything. You have to decide for yourself based on what you know to answer. > > Take your best shot and support your decision. > > I have asked you this numerous times. You have evaded every time. > > Put up or admit you got nothing. Your post reminds me of the time when a TV journalist collared me for a “man in the street” reaction on a news story I’d never heard. She showed me a headline (I think it was Man Sacked for Sexually Harassing his Secretary or something like that) and asked my opinion. I said I didn’t know the facts. She said sure, but what did I _think_? I said I didn’t know what he did, or she did, or what evidence there was, or anything about the case at all. She insisted that I had to have an opinion now that she’d shown me the headline, but I really didn’t. **Blake** ’s answer is “insufficient data”. Or “fucked if I know”. Why is that unacceptable to you? His best shot, if you held a gun to his head, would be a random choice. He couldn’t support a decision either way because it isn’t supportable. Why can’t he suspend judgement? Me, I’d say “life elsewhere.” Why? Because it’s cooler. Any justification really wouldn’t be anything more than that. ---
**Author:** ![Superfluous\_Parentheses](https://avatars.discourse-cdn.com/v4/letter/s/8edcca/32.png) [@Superfluous\_Parentheses](https://boards.straightdope.com/u/Superfluous_Parentheses)\ **Post date:** [November 10, 2010, 1:18pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/91 "2010-11-10T13:18:16Z")
> [@Blake](#): > > As I said _in the fricken’ OP,_ my argument is that the probability of extraterrestrial life may be as high as 1 (absolute certainty) or as low as 1/10^87. And your claim is also that it’s completely unknown where the actual probability lies between those points. If that’s true (and I don’t agree, but you’re welcome to the opinion), what you seem to be saying is that we _must_ assign a probability of 1/2 to the existence of life anywhere outside the earth, since life is either likely enough to happen more than once, or it isn’t and we can’t tell which it is. ETA: For my part, it seems pretty arrogant to assume that life is exactly so unlikely that it happened only once. ---
**Author:** ![wintertime](https://avatars.discourse-cdn.com/v4/letter/w/c68b51/32.png) [@wintertime](https://boards.straightdope.com/u/wintertime)\ **Post date:** [November 10, 2010, 1:22pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/92 "2010-11-10T13:22:25Z")
> [@Baboonanza](#): > > Christ, there’s no need to be rude. Right you are. But may I point out that Blake did indeed not make any statement that claimed any certainty at all about the (im-)probability of life in the universe - this actually is his point, that there is no certainty. He challenges this certainty that he considers to be false – and this is, imo, one of the most important duties in any scientifically oriented debate. ---
**Author:** ![Baboonanza](https://avatars.discourse-cdn.com/v4/letter/b/f475e1/32.png) [@Baboonanza](https://boards.straightdope.com/u/Baboonanza)\ **Post date:** [November 10, 2010, 1:27pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/93 "2010-11-10T13:27:02Z")
Perhaps ‘prevalent’ was a poor choice of word. What I meant was that there is nothing obviously exceptional about our little solar system, the universe is full of ones just like it. We don’t have any grounds to believe that conditions for life don’t exists anywhere else, but we don’t ‘know’ either way. Most people, including myself, assume that life must exist somewhere else because as you say it would have to be a vanishingly rare occcurence for it not to and there isn’t really any evidence that that’s the case. I am not (and I don’t think anyone else is either) pretending this is some sort of undisputable fact, just that given the coincidental ‘evidence’ it seems a more likely proposition, to me. If your position is ‘we don’t know’ then congratulations, you’re correct. You could have pointed that out much more easily, and without the apparent emotion. ---
**Author:** ![Superfluous\_Parentheses](https://avatars.discourse-cdn.com/v4/letter/s/8edcca/32.png) [@Superfluous\_Parentheses](https://boards.straightdope.com/u/Superfluous_Parentheses)\ **Post date:** [November 10, 2010, 1:30pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/94 "2010-11-10T13:30:58Z")
Question for **Blake** : what if tomorrow we find life on Europa, or Mars, or somewhere else, and we can prove it’s unrelated to life on earth? Would you still contend the chances of life on other worlds except the two we know about to be completely unknowable or would it change your position? ---
**Author:** ![Baboonanza](https://avatars.discourse-cdn.com/v4/letter/b/f475e1/32.png) [@Baboonanza](https://boards.straightdope.com/u/Baboonanza)\ **Post date:** [November 10, 2010, 1:33pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/95 "2010-11-10T13:33:26Z")
> [@wintertime](#): > > Right you are. But may I point out that Blake did indeed not make any statement that claimed any certainty at all about the (im-)probability of life in the universe - this actually is his point, that there is no certainty. > > He challenges this certainty that he considers to be false – and this is, imo, one of the most important duties in any scientifically oriented debate. I will admit to initially misundertanding his position, and I apologise for that. I would suggest that scientific debate is better conducted in more restrained language myself. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [November 10, 2010, 1:38pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/96 "2010-11-10T13:38:58Z")
> [@Superfluous\_Parentheses](#): > > And your claim is also that it’s completely unknown where the actual probability lies between those points. Pretty much. > [@](#): > > what you seem to be saying is that we _must_ assign a probability of 1/2 to the existence of life anywhere outside the earth, since life is either likely enough to happen more than once, or it isn’t and we can’t tell which it is. No, I’m saying, and have said numerous times, that we don’t know the odds. We have no idea what the odds are. We don’t know the odds and can not know the odds. The odds could be a million to one against, or they could be a million to one for. That is what I am saying. I am definitely not that the odds are are 1/2. To give an analogy, I would like you to tell me the likelihood the fist aliens we meet will have wings. Do you assign a 1/2 probability to them having wings? Why would you do that when you lack any information whatsoever about them? Me, I would take the scientific approach and say that either winged or wingless is plausible and that there is no way at all that we can know which is more probable. Any probabilities assigned are pure guesswork. > [@](#): > > ETA: For my part, it seems pretty arrogant to assume that life is exactly so unlikely that it happened only once. Such an assumption isn’t arrogant. Arrogance doesn’t enter into it. It is stupid and ignorant and illogical and totally without basis. We can have no idea how unlikely life is. This position is as ignorant and evidence free as a position that because there are lots of Earth-like planets, life must have happened lots of times. ---
**Author:** ![Superfluous\_Parentheses](https://avatars.discourse-cdn.com/v4/letter/s/8edcca/32.png) [@Superfluous\_Parentheses](https://boards.straightdope.com/u/Superfluous_Parentheses)\ **Post date:** [November 10, 2010, 1:43pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/97 "2010-11-10T13:43:00Z")
> [@Blake](#): > > Such an assumption isn’t arrogant. In my experience, the people who assert such a position generally do so out of an inflated sense of the importance of earth-bound, if not human, life. That doesn’t mean everybody who does so is that arrogant, but humans have an amazing capacity to think of themselves are precious special creatures. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [November 10, 2010, 1:44pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/98 "2010-11-10T13:44:41Z")
> [@Blake](#): > > A sense? Sure. A scientific basis? No. Wrong. What you won’t have is proof. You are not understanding the concept of an educated, scientifically based theory. Theories are not proof, and they don’t require proof, no matter how much you want proof. > [@](#): > > Utter, baseless nonsense. I have said repeatedly and bluntly that we have formed multiple hypotheses. Many of them mutually contradictory. Oh Noes! Someone may have a theory that is incorrect! Time to stop with this science nonsense until these idiots understand that they are not allowed to have theories without absolute proof that they are correct. > [@](#): > > No, you can guess, just as you can guess whether the first aliens we meet will have gills or wings. > > We have absolutely no way of \*justifying \*the answers from either of those guesses, but we can certainly make the guess. > > I guess wings. Am I right? You’re saying that there is absolutely no justifiable way to estimate the likelihood of life on other planets, ever, under any set of circumstances. You either have absolutely no idea whether or not there is life out there, or you’ve discovered life out there, and proven it without a doubt. Talk about nonsense. ---
**Author:** ![wintertime](https://avatars.discourse-cdn.com/v4/letter/w/c68b51/32.png) [@wintertime](https://boards.straightdope.com/u/wintertime)\ **Post date:** [November 10, 2010, 1:44pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/99 "2010-11-10T13:44:42Z")
> [@Baboonanza](#): > > If your position is ‘we don’t know’ then congratulations, you’re correct. You could have pointed that out much more easily, and without the apparent emotion. I won’t speak for anyone else, of course, but in my case the debate ist not about “we don’t know” but “what, exactly, do we know and what do we believe to know but actually don’t?” ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [November 10, 2010, 1:44pm UTC](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137/100 "2010-11-10T13:44:43Z")
> [@Superfluous\_Parentheses](#): > > Question for **Blake** : what if tomorrow we find life on Europa, or Mars, or somewhere else, and we can prove it’s unrelated to life on earth? Would you still contend the chances of life on other worlds except the two we know about to be completely unknowable or would it change your position? It would depend on some other factors. Will it suffice to say that it _should_ give us a basis for probability calculations. [Previous page](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137.md?page=4) [Next page](https://boards.straightdope.com/t/basis-of-sciences-belief-that-extraterrestrial-life-is-likely/560137.md?page=6)