Why we're the only intelligent life in our galaxy

[DemoCoder]

What is being added is the attempted observation, and the failed observation. It eliminates a class of possible life. It doesn't eliminate the possibility, but it whittles it down.

(hypothetical example)

Hypothesis: Life, as best we can define it, exists on Jupiter. Let's say that life is not just defined by presence of organic molecules, but also by detection of "interesting' distributions in the mass spectrum, or by electromagnetic emissions that have motifs or outliers (see a reference on time series datamining, novety detection, if you dont understand the terms).

Experimental setup: we perform several tests, send space probes, analyze atmospherical gasses, look at magnotometer readings, look for EM emissions, etc etc

Result: null

Inference: adjust confidence in that particular hypothesis downward.

Does this mean that metallic hydrogen beings of rod-logic don't exist in Jupiter's core? No.

But it eliminates of a class of possible life, lowers the confidence that life exists. Belief in a hypothesis is influenced by the sum of probabilities of all mutually exclusive hypotheses. There could be an finite number of these, but every false one affects the outcome. (yes, unless you inspected every single molecule of Jupiter, you can't rule out no life, but if a planet has life, active life, we expect it is common, but a minority that needs a fine tooth come to find it in one corner)

You can argue all you want. What I am presenting you isn't my opinion, and it isn't conjecture. It is mathematics. If you want to speak of probabilities, then you are talking mathematics, and I am simply telling you what a Bayesian reasoner might tell you.

The problem I have with you DiGuru, is that you say things like "we don't know", and try to argue lack of information, but then turn around and claim things like "the most plausible scenario is the aliens are near to us, but hiding" Umm, OK! And how did you calculate THAT?

You don't like what the math tells you based on null observations, but then go full steam ahead arguing greater probabilities for stuff which you have zero evidence at all, and a whole bunch of null observations on your tail.


You don't like what

 

[Frank]

The problem I have with you DiGuru, is that you say things like "we don't know", and try to argue lack of information, but then turn around and claim things like "the most plausible scenario is the aliens are near to us, but hiding" Umm, OK! And how did you calculate THAT?

Where did I do that? I didn't. In response to the original statement: "there are no aliens, because we don't see any and they would definitely be here if there were", I just offered up a whole bunch of alternative viewpoints. Including a good reasoning of how the Fermi paradox might be solved.

You don't like what the math tells you based on null observations, but then go full steam ahead arguing greater probabilities for stuff which you have zero evidence at all, and a whole bunch of null observations on your tail.

I didn't. You might have thought I did, if you read it with the assumption that I was trying to prove that alien life does exist.



Just as some participants here don't like statements such as: "intelligent life has to exist, because we do and it's a huge universe", others don't like statements that "life anywhere else than on Earth doesn't exist, because we haven't seen any yet". I don't like either line of reasoning. They're both flawed.

 

[DemoCoder]

#1 you claimed that ET's were near and hiding and that was the most plausible scenario to explain Fermi Paradox, which defies logic. A universe with life distributed at greater distances would in fact be more plausible just due to the copernican principle and the principle of mediocrity (what's so special about our little galaxy neighborhood that should have such a cluster)

#2 the "sheer size" argument and the "null observation" argument are not equivalent. The first argument fails because it doesn't even take into account the probabilities and range of numbers being used. The "null observation" argument is in fact, perfectly legit. Each year for example that SETI fails to detect anything, it rules out more possibilities. It doesn't eliminate the chance that life is out there, but it rules out with greater and greater confidence that it is abundant and communication on the wave lengths being searched (nearby atleast)

The failure to observe evidence for a theory does imply that confidence in the theory should be lower.

Take Cold Fusion. Everytime a null observation occurs (neutrons, energy output, etc) people fall back and claim that you didn't test Alloy X, or that some new unknown process is happening, and you arguing seeing it because it may be using particles you aren't looking for. But the more and more experiments that fail to observe > unity output, the lower the confidence.

There are two things that lower you confidence in a theory: Lack of evidence (can't observe a prediction), and contradictory observations (phenomena occur that your theory doesn't predict should happen)

 

[Frank]

1. I didn't. Really. I make no claim anywhere in this thread that aliens are near and/or hiding. Or that there are any at all. Really. I didn't.

But, just as you are trying to show me that statistics dictate that there is no life but on Earth because we haven't found any so far, and thus all other possible planets and whatever that might exist count against there being life, I'm trying to show you that we don't know that. Life can be around the corner, for all we know. We just haven't got the means to see it if it doesn't come to us and introduces itself.

2. You have to turn it around. If I cannot hear the sound made by a flea at the other side of the Earth, does that mean that it isn't there, or just that I'm unable to hear it? What is SETI able to hear? THAT is all you can rule out.

 

[DemoCoder]

But, just as you are trying to show me that statistics dictate that there is no life but on Earth because we haven't found any so far,

I never said statistics dictate that. I said that statistics dictate that we should believe the hypothesis "there is life on other planets" with less confidence each time there is a negative confirmation when conducting experiments to confirm it.

You have to turn it around. If I cannot hear the sound made by a flea at the other side of the Earth, does that mean that it isn't there, or just that I'm unable to hear it? What is SETI able to hear? THAT is all you can rule out.

Everytime you rule something out, you lower the likelihood. I have an urn filled with colored balls that may or may not contain a red ball. I have a theory that there is a red ball in the urn. I withdraw 10,000 balls. No red balls detected. I withdraw 1 million balls. No red balls detected. Can there still be a red ball? Yes, there is a non-zero probability. We don't know how many balls are in the urn. But chances are better than not, that there isn't a red ball, according to statistical reasoning about beliefs. It's just that simple. I'm not going to explain it again. I really encourage you to go get a book on Bayesian inferencing, or read up on Bayesian belief networks.

 

[Frank]

Btw, about SETI: if you want to communicate efficiently, you're not going to use something resembling morse code. You're going to use an efficient transmission protocol, that packs the data and includes error correction. And uses things like frequency hopping. And when that transmission protocol becomes more and more effective, it starts to resemble random noise more and more. How are you going to tell a really efficient signal from random noise? Especially if it shifts around all the time or uses a broad spectrum?

And if you want efficient, you use a directional beam, or even better: a laser. There's not much chance we would accidentally pick that up, is there?

 

[Frank]

I never said statistics dictate that. I said that statistics dictate that we should believe the hypothesis "there is life on other planets" with less confidence each time there is a negative confirmation when conducting experiments to confirm it.

Everytime you rule something out, you lower the likelihood. I have an urn filled with colored balls that may or may not contain a red ball. I have a theory that there is a red ball in the urn. I withdraw 10,000 balls. No red balls detected. I withdraw 1 million balls. No red balls detected. Can there still be a red ball? Yes, there is a non-zero probability. We don't know how many balls are in the urn. But chances are better than not, that there isn't a red ball, according to statistical reasoning about beliefs. It's just that simple. I'm not going to explain it again. I really encourage you to go get a book on Bayesian inferencing, or read up on Bayesian belief networks.

Yes, I understand that completely. But the analogy is flawed. It would be more like: I have an urn filled with balls that all have a different size and color. When I open a single ball, I see that there is a number inside. What are my chances of there being another ball that contains the same number?

Let's say it's a red ball. There are other red balls, but no two have the exact same color. And the ball is rather small. There are other balls of roughly the same size, but none of those is exactly the same size. Does that help you to determine your chances?

Let's say we're interested in any number that is more or less equal to that first number, instead of only the same number. Can we even say within what boundaries that would be, if we have no idea about the range of all the numbers? Or how they compare to one another?

Now we take another ball (the one that is easiest to grab), look inside and we see no number. While we could speculate that there is a number inside, but that we cannot find it, we assume that it contains none. Does that say anything about the chances of the other balls containing numbers? Other than that some might have one, and others might not?

So, can you tell me how many and which balls contain a comparable number to the first one?

 

[DemoCoder]

Yes, you can detect all of that. I'll give you an example. The very best encryption routines strive to deliver histograms of ciphertext occurance that are uniform, and without periods, or patterns. Can I distinguish this if someone was using it to communicate? Yes, it would stand out like a sore thumb, because the universe doesn't produce natural em signals with such distributions. Pulsars are nice and repetitive for example. Natural signals except for certain radiation sources, don't deliver uniformly distributed and completely random patterns.

It gets even better. It turns out that detecting surprising patterns, even when the surprise is that you get a random pattern, is very efficient. But rather than explain it, take a look at this easy to read . n00b PowerPoint

 

[DemoCoder]

Yes, I understand that completely. But the analogy is flawed.

It doesn't change anything.

It would be more like: I have an urn filled with balls that all have a different size and color. When I open a single ball, I see that there is a number inside. What are my chances of there being another ball that contains the same number?

If you withdraw 10,000 balls, and none of them have the same number, your confidence should be lower. The chances of a pair of any thing resembles the birthday paradox, and that effectively change what is an infinitesimal probability into the square root of that probability.

Let's say we're interested in any number that is more or less equal to that first number, instead of only the same number. Can we even say within what boundaries that would be, if we have no idea about the range of all the numbers? Or how they compare to one another?

Amazing yes. Go lookup the Sultan Dowry's problem, or better yet, The Doomsday Argument. Using a DA-esqu argument, one could put bounds on the range of numbers, and using the number of trials conducted, calculate odds of finding a close match.

 

[Frank]

If you withdraw 10,000 balls, and none of them have the same number, your confidence should be lower. The chances of a pair of any thing resembles the birthday paradox, and that effectively change what is an infinitesimal probability into the square root of that probability.
...
This is getting tiring now.

Ok, we'll come back to it when we have examined 10,000 balls. Shouldn't take more than a couple of centuries, if we're lucky.

 

[DemoCoder]

Ok, we'll come back to it when we have examined 10,000 balls. Shouldn't take more than a couple of centuries, if we're lucky.

DiGuru, really, what is the point of your arguments? The mathematical argument simply tells you logically which direction to adjust your confidence. Each observation right now, might only adjust it an insignificantly fraction downward.

That's not the point. The point is the direction of the adjustment. There are people in this thread going "I have sampled 1 red ball from the urn! Therefore, another red ball is likely" (Earth implies likely other earths!) And I'm saying you sampled 1 red ball, but after that, you got nothing but black balls for years. The confidence levels are not adjusting upwards, they are adjusting downwards, and your optimism is not justified by the evidence.

It's that simple. At best, observation of earth is inconclusive evidence. At worst. null observations should make you pessimistic. There is no justification for the level of certainty being bandied about by people, or even the statement that life elsewhere is "likely" There is no logical justification for such a statement.

 

[Bouncing Zabaglione Bros.]

1. I didn't. Really. I make no claim anywhere in this thread that aliens are near and/or hiding. Or that there are any at all. Really. I didn't.

But, just as you are trying to show me that statistics dictate that there is no life but on Earth because we haven't found any so far, and thus all other possible planets and whatever that might exist count against there being life, I'm trying to show you that we don't know that. Life can be around the corner, for all we know. We just haven't got the means to see it if it doesn't come to us and introduces itself.

2. You have to turn it around. If I cannot hear the sound made by a flea at the other side of the Earth, does that mean that it isn't there, or just that I'm unable to hear it? What is SETI able to hear? THAT is all you can rule out.

If you're saying fleas are everywhere, you'd feel them biting you.

It's just that you are saying "we don't know" and then concluding that complex intelligent life might be out there. You can't use the fact that we can't prove a negative as evidence to support your own viewpoint. Others are saying "we don't know" and concuding that we have no evidence of life yet, even though our ability to gather evidence one way or another is improving all the time, and what we've looked at so far doesn't show life, let alone complex life.

You can't just handwave the statistics and say "but there's so many stars out there, it must be the case". Look at it this way. To get complex intelligent life that takes the steps to becoming a long-lived, starfaring and colonising species (which they must become if they are not to die out quickly with their planet or star) takes a lot of steps in their favour. Even we haven't managed to go all the way to the stars yet.

Let me try a simplified analogy:
Imagine it takes a billion coin tosses all landing heads up to get to the stars - a very rare set of circumstances and decisions. Each star out there is tossing coins, and although each coin toss is 50/50 regardless of the one before, we're after a consecutive billion heads up, which is a very rare statistical probability.

You will no doubt say "but there's so many stars out there, some of them are bound to have tossed a billion coins that came up heads", but it doesn't work that way. Each time a coin toss happens, there's a 50/50 chance of a star breaking that billion-heads-up run. Each time a coin toss happens, half the stars tossing coins can be wiped off the list of those that can create a starfaring race because they failed to complete the billion-heads-up run. Those stars failed to propogate complex, intelligent life.

Statistically, some of these stars will fail in their 50/50 coin tosses quite early on, not having suitable planets or suitable atmospheres. Some will survive longer, maybe making simple life. Those that manage to successfully toss a billion coins all heads up in a row will be very rare indeed. It's such a complex route, there are many, many oportunites for the coin toss to land tails up and break the required chain of results. We've come a long way, maybe to within a few hundreds of years depending if we go posthuman, but even we're still not there yet.

You could insist that there's so many stars out there it must have happened, but the more stars out there tossing coins, the more likely it is these few successful stars will probably be spread out in time and space, so we may never meet the result of the few successful runs that have managed to go all the way through the billions of correct "choices" to get a starfaring race.

You can't say "there's so many stars out there there must statistacally be aliens". If anything you have to say that there are so many stars out there, that statistically most of must have failed somewhere along the very complex route to creating a long-lived, starfaring race, and the more stars you put into the mix, the more you decrease the likelihood that they are close enough in time or space that we could ever meet them.

To hold out hope of advanced complex life just based on "chances are" with no real evidence is just an act of faith, no more provable or likely than suggesting a supernatural being has made it so. You certainly can't handwave the statistics and say they support you based on the lack of better information.

 

[Frank]

DiGuru, really, what is the point of your arguments? The mathematical argument simply tells you logically which direction to adjust your confidence. Each observation right now, might only adjust it an insignificantly fraction downward.

That's not the point. The point is the direction of the adjustment. There are people in this thread going "I have sampled 1 red ball from the urn! Therefore, another red ball is likely" (Earth implies likely other earths!) And I'm saying you sampled 1 red ball, but after that, you got nothing but black balls for years. The confidence levels are not adjusting upwards, they are adjusting downwards, and your optimism is not justified by the evidence.

It's that simple. At best, observation of earth is inconclusive evidence. At worst. null observations should make you pessimistic. There is no justification for the level of certainty being bandied about by people, or even the statement that life elsewhere is "likely" There is no logical justification for such a statement.

Yes, I know.

But then again, if there were a thousand Earths in this Galaxy, all containing humans, all having our current development, what would be our chances of being able to spot one? If it's not in our solar system, those chances would be almost nonexistent.

 

[KimB]

If you're saying fleas are everywhere, you'd feel them biting you.

It's just that you are saying "we don't know" and then concluding that complex intelligent life might be out there. You can't use the fact that we can't prove a negative as evidence to support your own viewpoint. Others are saying "we don't know" and concuding that we have no evidence of life, even though our ability to gather evidence one way or another is improving all the time, and what we've looked at so far doesn't show life, let alone complex life.

Well, as far as our own observations have gone, we have essentially zero statistical power to say anything about the existence of life anywhere except within our own solar system, and even then we're not sure with a couple of planets.

The statement that there is no intelligent life in the galaxy besides ourselves requires more argument, and a few assumptions, and is thus subject to failure. I don't think that there's intelligent life in our galaxy besides us, based upon the argument I've given, but that doesn't mean that we can say we've found evidence that there isn't intelligent life in the galaxy besides ourselves. Lack of evidence is not evidence of lack: it may just be that the thing one is looking for is naturally hard to detect.

 

[Frank]

If you're saying fleas are everywhere, you'd feel them biting you.

But I'm not. Good thing, isn't it?

It's just that you are saying "we don't know" and then concluding that complex intelligent life might be out there. You can't use the fact that we can't prove a negative as evidence to support your own viewpoint. Others are saying "we don't know" and concuding that we have no evidence of life, even though our ability to gather evidence one way or another is improving all the time, and what we've looked at so far doesn't show life, let alone complex life.

I don't. And I would agree to that description.

You can't just handwave the statistics and say "but there's so many stars out there, it must be the case". Look at it this way. To get complex intelligent life that takes the steps to becoming a long-lived, starfaring and colonising species (which they must become if they are not to die out quickly with their planet or star) takes a lot of steps in their favour. Even we haven't managed to go all the way to the stars yet.

I didn't.

Let me try a simplified analogy:
Imagine it takes a billion coin tosses all landing heads up to get to the stars - a very rare set of circumstances and decisions. Each star out there is tossing coins, and although each coin toss is 50/50 regardless of the one before, we're after a consecutive billion heads up, which is a very rare statistical probability.

Agreed.

You will no doubt say "but there's so many stars out there, some of them are bound to have tossed a billion coins that came up heads"

NO, I WOULDN'T!

, but it doesn't work that way. Each time a coin toss happens, there's a 50/50 chance of a star breaking that billion-heads-up run. Each time a coin toss happens, half the stars tossing coins can be wiped off the list of those that can create a starfaring race because they failed to complete the billion-heads-up run. Those stars failed to propogate complex, intelligent life.

Agreed.

Statistically, some of these stars will fail in their 50/50 coin tosses quite early on, not having suitable planets or suitable atmospheres. Some will survive longer, maybe making simple life. Those that manage to successfully toss a billion coins all heads up in a row will be very rare indeed. It's such a complex route, there are many, many oportunites for the coin toss to land tails up and break the required chain of results. We've come a long way, maybe to within a few hundred of years depending if we go posthuman, but even we're still not there yet.

Yes.

You could insist that there's so many stars out there it must have happened

No, I won't.

, but the more stars out there tossing coins, the more likely it is these few successful stars will probably be spread out in time and space, so we may never meet the result of the few successful runs that have managed to go all the way through the billions of correct "choices" to get a starfaring race.

Yes.

You can't say "there's so many stars out there there must statistacally be aliens". If anything you have to say that there are so many stars out there, that statistically most of must have failed somewhere along the very complex route to creating a long-lived, starfaring race, and the more stars you put into the mix, the more you decrease the likelihood that they are close enough in time or space that we could ever meet them.

Exactly!

To hold out hope of advanced complex life just based on "chances are" with no real evidence is just an act of faith, no more provable or likely than suggesting a supernatural being has made it so. You certainly can't handwave the statistics and say they support you based on the lack of better information.

Good thing I don't, isn't it? And I'm not even disagreeing with the statistics either! Wow!

What I do say, is that we have so very few datapoints, that that statistic isn't even in the same ballpark by a few orders of magnitude to being significant. That's it.

So, NO, it doesn't disprove anything either.

 

[NANOTEC]

Try this scenario.

Two teams of scientists team A and team B try to test a new very abstract and bold hypothesis one that was developed today. Team A uses existing tools and methods. Team B uses tools and methods developed 500 years into the future. Which team has a higher chance of detecting more "unknowns"? Of course the answer is team B. Continuing: Unknown X can only be detected with tool Y that was invented 100 years into the future. Can team A ever detect unkown X at the present time? If no then can team A logically conclude that unknown X does not exist?

 

[Druga Runda]

I think you're making a basic mistake here a that a lot of people make. You're saying "gee we were so lucky to get this great planet, and there's so many other stars out there, there must be other places where there's intelligent life and other lucky planets. If there wern't all these great planets out there, how could we have got one?" However, because Earth is so amenable to life (for a short time anyway), it's almost a certainty that life would evolve here. If this was the only place in the galaxy where life could form, this would then be the most likely place we'd see life in the galaxy.

Finding life on Earth doesn't really tell us anything about life elsewhere. Statistically we could very well be the most amenable place to life, and thus the most likely place to have it. We just don't have any evidence of complex life elsewhere to be able to use statistics to tell us about the greater galaxy. Sometimes things happen in a given place because it's something that happens often, and one place is as likely to see this particular happening as another. Sometimes things happen in that place because that's a particularly good place for it to happen.

Even when you take into account the large numbers of stars and try to do some statisical handwaving, you have to take into account the very few places with all the requisite physical parameters, and then the complex chain of events that led us to becoming a dominant, intelligent species in a relatively short timescale. Then you have to do it all again for another species, and factor in the chances of them being physically close in space as well as time. The chances of all these things coinciding are very small indeed. The numbers, space and time involved are just too big for the chances to be anything more than one in billions of billions ad infinitum that we're next door to each other.

I might as well claim that statistically it's far more likely that there are no civilizations near us (because there's a lot more space that isn't near us), and they are long gone or not yet formed (because there's a lot more time in the past and in the future than now). But that would just be conjecture. The difference is my conjecture is based on the evidence we have in front of us. Your conjecture is based on evidence that we're just making up out of thin air and pulling from sci-fi books.

You have to reverse your thinking on the "chances of things" happening. Look at it this way: what were the chances of you getting into an auto accident on your way to work this morning? It didn't happen, so after the fact, we can say that your chances were a complete zero percent. The accident didn't happen. Were the probabilites any different before you set out for your journey as when you arrived at work? Just because you "could have" had an accident?

If the galaxy was teeming with life, wouldn't some of it have travelled? Wouldn't the numbers be big enough that we'd see some evidence of a technologically advanced starfaring race? If they never became starfaring, they would have died out with their home star, but surely some of them must be technologically more advanced than us and colonising? But I can say that we've not got that evidence, so we statisically can say with certainty that it's not happened to us, despite all the billions of stars and billions of years that should have given that opportunity if the numbers were there to favour your argument that the vast numbers of stars ensure intelligent life.

If you can say "all these stars guarentee intelligent life", why can't I say that "all these stars guarentee intelligent life, some of which will be starfaring and should have already visited us publicly with FTL spaceships"? But that's not what happened. Or are you suggesting that there's lots of life out there (lots of stars) but none of it is starfaring, and none of it was living anytime before us? They just all sat at home and waited for their stars to go out, none of them ever got more advanced than us and decided to go travelling?

surely we have two different ideas here.

One - according to what we can discover at present we have not come across intelligent life other than our own, thus there is nothing nearby, or even far away.

Two - we are, so given similar conditions that were present for us to come to existance, there should be others too.

As it stands the "no life" idea is obvious. All the direct information our civilization has been able to collect about that premise to this point in time points towards "no life".

I cannot challenge that fact, but I can ask the question: Why has that not been the case? and "no life" is not the only possible answer to it. To me such answer is more akin to medieval "the sun revolves around the earth", because it is obvious that is the case, take a look in the sky and what do you see? In medieval case sun revolving around earth, and in this case - we see nothing at all, thus surely there is nothing.

Where my interest lies is in approaching the question from a different direction. The one is if there was other intelligent life, would colonization be an obvious route for them? (in case of original Chalnoths proposition). To me the answer is : not necessarily, for the reasons outlined before.

Second point is: Would we necessarily be able to detect it at this point in our development? Highly doubtful.

We needed to get almost to the 21st century to discover life without sunlight on our own planet, due to its rarity. To be certain that we should have been able to detect life, or that the same life would come here and say "hello there inteligent solar system dudes, let us teach you how to live your life" by now is pushing it a lot.

Not to mention that if there is intelligent life out there it will be markedly different to what we can even imagine due it its magnitude of further development comparing to our own. To me this very magnitude of most likely millions intelligence development years, is a good indication that we should be incapable of their detection no matter how hard we try with present technology, and that if there is anything they would be markedly different to us as we are at the moment in all aspects, both physical, social and technological. Furthermore I would say that it would be much more unlikely that if we meet someone that they would be in some near stage of development to us, let's say 10k years +-. The difference is much more likely to be measured in millions of years of "existance of civilization" where we are at the very beginning of this stage.

So I would not first question their capability to travel but our capability to detect them. Looking it in another way, why are we as the civilization investing any effort at all into looking for life elsewhere if the quest is so obviously futile.

Clearly, neither we have contact with them, nor can we say that there is certainly noone out there, thus it is an open question and as such it deserves attention.

The statement " If this was the only place in the galaxy where life could form, this would then be the most likely place we'd see life in the galaxy." is no more accurate than stating "there is other life in the galaxy, but we cannot detect it with present techonlogy" as clearly we are not at the point to >prove< one or another, still this is not a totally futile exercise .

I would say that the main difference in my argument with Chalnoth would be that he thinks that colonization is inevitable consequence of further development of intelligent life, in which case I disagree with him, and to me it is not inevitable. Furthermore a civilization that has a few thousand years more development is immensly more advanced than the other one who hasn't got it, let alone millions, and the propensity to "spread" is certainly not the strongest trait, as destruction or annhillation of life or everything else is much easier to execute for an advanced civilization no matter how small spread wise it might be if it has advanced knowledge in comparison. But as I said when a civilization goes a lot past to the point of knowledge we have achieved it will either self-destruct or change into an "integrated society" where "might is right" will not be in its interest anymore, because the "mighty" would be able and would have to destroy everyone else to keep his "mighty" status, as I outlined in one of my arguments in the posts before.

If you can say "all these stars guarentee intelligent life", why can't I say that "all these stars guarentee intelligent life, some of which will be starfaring and should have already visited us publicly with FTL spaceships"

[font=&quot]I would say is that this is very self-important to imagine that some of them would come here and announce themselves "Hello, lets us give you a hand", thinking that we are not even at the point to handle our own technology and live in peace with each other. Imagine us at present possessing some advanced tech, we would surely self-destruct, and this option is still on the table, just wait for nuclear knowledge to spread, or for bioweapons in your personal lab to become possible. I think we could agree those are one of the greatest and real threats for our continued existence. [/font]

Perhaps if we in some near future (10k years or so) start to travel around and if we still posses current attitudes towards exploitation and destruction of anything that doesn't suit us first, we might be visited and told off. Otherwise I highly doubt we will get some kind of interaction (sci-fi style), as there is not much point to it as I see it. And surely whatever is out there is far far more advanced than we are as well they had a few million years ahead of us to get where they are now.

Furthermore one could construct an argument that "religions" as they are at the heart, have very unnatural ideas containing high moral values, that in principle would bring certain destruction to their followers if followed correctly, at the time of the conception. Their "might is right" contemporaries would slaughter them, as it often happened too. (no need to say that organizations created around those ideas function based on "might is right" ) In any case all those old "creators of religions" were connected, or claimed authority from non-earth beings could be a clue, but than again this cannot be argued effectively, in order to prove something. It's more like - this could be another hint, so not only they got to valid moral ideas very early, but they even claimed inspiration from "above".

If there is anything out there I would say expect to meet something akin to us is very very unlikely, but something far far more advanced, should be likely.

I hope that answers DC's points as well, but just to point towards this one

This is why people believe in psychics, or synchronicity. They only count positive evidence, positive predictions, and forget or ignore the millions of negative unsuccessful predictions or coincidences.
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But this excuse does not mean that people's belief in a hypothesis won't be revised by null evidence. It will. The more and more null evidence, the less belief in the hypothesis will be justified. One can always invent more and more reasons why null evidence is continually seen, and the dreamers will hold onto this explanation to try and avoid revising their confidence in the extrasolar life hypothesis, but the rules of probability say you should in fact, revise your belief confidence level.

This is the fundamental problem people have in dealing with statistics and probabilities: they ignore null evidence, because human beings only react to surprising or "new" evidence.

sure, physics can be relatively easily tested, you can't really put the alien into testable position. You can only discuss the idea why could they exist or not, or whether they might be here and why they are not. It is well beyond our current abilities to do much about it, confirming either a positive or a negative. That is a fundamental problem with the "alien" hypothesis, we are not nor will we be in any near future able to detect their existence, so the only other option is to wait for their "will" to show themselves or to discuss the possibilities.

Main problem with DC attitude is "if they are out there we would either be able to detect them or they would show themselves to us".

Point being is that this discounts the "by far highest" chance, that if there is something intelligent out there - they are far far more advanced than we are, as they had millions of year ahead of us. That is for civilizations from our own galaxy, let alone one from somewhere else.

You are very keen to think of something else as within thousands of years of comparable developoment to us + somewhere near. I say that this is very unlikely as well, but to discount all intelligence on that basis does not seem very rational to me.

it may just be that the thing one is looking for is naturally hard to detect.

this to me is the most likely conclusion, for the reasons outlined before, expecting existing intelligence to be in the same ballpark development stage as us, and near us is really really unlikely. Not to say that it is impossible, but if that was the case we would ahve already discovered them, or they might be intrigued to contact us if they were ahead enough, but were impressed with discovering us. From my POV if there is something out there than it is far far ahead of us, well beyond our ability to detect them for a long time to come.

 

[NANOTEC]

Druga Runda your thoughts echo mine.:smile:

 

[Frank]

GREAT post, Druga! I totally agree.

 

[Bouncing Zabaglione Bros.]

One - according to what we can discover at present we have not come across intelligent life other than our own, thus there is nothing nearby, or even far away.

You're assuming that a lack of evidence to support a negative is a positive support for your argument.

The statement " If this was the only place in the galaxy where life could form, this would then be the most likely place we'd see life in the galaxy." is no more accurate than stating "there is other life in the galaxy, but we cannot detect it with present techonlogy" as clearly we are not at the point to >prove< one or another, still this is not a totally futile exercise .

We can prove to ourselves that complex intelligent life is on earth. We cannot prove that it is elsewhere. Until we have proof, we can't assume that life is out there. An absence of negative proof that life is not out there is not the same as proving life is out there. You're ascribing a lack of proof the same weight as proof, even though it's impossible to prove a negative.

Any sort of complex, intelligent life would have to ultimately become starfaring. If they didn't then they wouldn't last very long on a galactic scale, ultimately going extinct the first time a major planet killer ever happened, they ran out of resources or screwed up their planet, and eventually when their star died. We'd have almost no chance of meeting them if they couldn't expand away from the limits of their original star. Almost by definition, any advanced, longlived race would have had to become colonisers in order to become an advanced, long lived race.