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  #1 (permalink)  
Old 30-April-2008, 10:50 PM
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Default Why I hope the search for extraterrestrial life finds nothing.

Why I hope the search for extraterrestrial life finds nothing

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But I hope that our Mars probes discover nothing. It would be good news if we find Mars to be sterile. Dead rocks and lifeless sands would lift my spirit.

Conversely, if we discovered traces of some simple, extinct life-form--some bacteria, some algae--it would be bad news. If we found fossils of something more advanced, perhaps something that looked like the remnants of a trilobite or even the skeleton of a small mammal, it would be very bad news. The more complex the life-form we found, the more depressing the news would be. I would find it interesting, certainly--but a bad omen for the future of the human race.
(Click on "Print" up at the top to condense the multiple pages down to one.)
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Old 30-April-2008, 11:16 PM
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I hardly think that the absence of extraterrestrial life insures any kind of great future for humanity. A lifeless void would surely guarantee a healthy supply of real estate and resources. But it would also encourage those dimwits who think there's no real reason to have a space program BECAUSE it's a lifeless void.

If we found life, I think it would promote research and funding, and reignite the interest the general population once had for exploration.

Pretty rocks and flow charts don't inspire Joe Public to do anything but flip the channel.

If we found anything that was alive -- like Europan Sea Monkeys -- at least some people would wake up and have something to occupy their minds instead of Lindsay's or Paris' recent pantiless reemergence from rehab.

We need to know that we're not alone.

The religious zealots need to know it so they'll stop harping about how 'special' humans are. I mean, if God(s) made us in His/Her/Their own image, then who made the Greys?

We need a kick in our complacent primate booties. Even if they're monstrous bloodthirsty creatures from Whatevatopia, or just Tribbles.

We need to know that we don't own it all, and we just might need to push harder to make ourselves better than we already are.
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Old 30-April-2008, 11:19 PM
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From these two facts it follows that the evolutionary path to life-forms capable of space colonization leads through a "Great Filter," which can be thought of as a probability barrier.
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Now, just where might this Great Filter be located? There are two possibilities: It might be behind us, somewhere in our distant past. Or it might be ahead of us, somewhere in the decades, centuries, or millennia to come. Let us ponder these possibilities in turn.
OFCOL Thanks ToSeek I just wasted 4210 words.

There are more than two possibilities. For instance, the "Great Filter" might be ten gazillion years wide and we might be at any point along it.

PS: Nick Bostrom's home page "Director of the Future of Humanity Institute at Oxford University. Philosopher, polymath, leading transhumanist thinker and spokesperson."
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Old 30-April-2008, 11:25 PM
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I'm a wee bit annoyed.

I clicked the link here in Firefox... It took forever to load.
Read page one- Hit for page two...
It gave a funny URL and a blank screen saying "done."

Did that twice- and did that anytime I hit "print" at the top.

Copy and pasted the link into I.E.

Accepted all their cookies in the off chance that they were annoyed by my rejecting their lint encrusted stale cookies.
I got the first page up- clicked right to page two... It was that author going on and on about Great Filter... OK <Skim Skim> <whatever>. Went and clicked page three...
"This Page Cannot Be Displayed."
Did that three times in a row.

Considering what I saw on the first two pages, I didn't really think I needed to waste my time fighting their website only to read 4 more pages of it trying to satisfy my curiosity about what this droning guys beef was


Hopefully, the author does not read this post.
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Old 01-May-2008, 01:50 AM
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Arguement seems to be based on two assumptions:

1. Space aliens would come to our solar system and do stuff we would notice.

2. The first bunch of aliens to colonize the galaxy would do nothing to prevent other aliens from coming to earth and doing stuff that we'd notice.

Since we know of only one advanced technology using species, ourselves, we can conclude nothing from our sample of one. We have no reason to conclude that aliens would act as we think we would act ourselves. In fact, when you look at history you can see our own attitudes have change dramatically over very short periods of time. One hundred years ago many supposedly civilized people had no problem with the idea of exterminating humans that belonged to what they called "lesser races." Nowadays, fortunately most of us find the idea abhorrent. A hundred years ago people wrote about the thrill of killing the last member of a species and making it extinct. Now we frown on that sort of behaviour. People used to look forward to the day when all wilderness would be replaced by farms and cities. White people used to be considered athletically superior to black people. Basketball used to be a Jewish sport. Since we can't seem to get our own motivations straight for more than a generation, I don't see how we can conclude much about alien motivations.
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Old 01-May-2008, 12:26 PM
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Bostrom is a profound thinker, but I think that his suggestion that finding dead vertebrates on Mars would be Bad News is going a little too far. The fact that Mars might have supported complex life that then died out has no real relevance for the Earth- that planet is entirely different in many characteristics to our own, so may be intrinsically more likely to become a dead planet.

A dead Mars with fossils doesn't imply anything about the existence of a Great Filter that eliminates intelligent life on Earth-like worlds.

However a Dead Mars with cities might give a hint or two... That might suggest that intelligent life tends to die out, despite the emergence of civilisation.
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Old 01-May-2008, 02:21 PM
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From the article:
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If--as I hope is the case--we are the only intelligent species that has ever evolved in our galaxy, and perhaps in the entire observable universe, it does not follow that our survival is not in danger. Nothing in the preceding reasoning precludes there being steps in the Great Filter both behind us and ahead of us. It might be extremely improbable both that intelligent life should arise on any given planet and that intelligent life, once evolved, should succeed in becoming advanced enough to colonize space.

But we would have some grounds for hope that all or most of the Great Filter is in our past if Mars is found to be barren. In that case, we may have a significant chance of one day growing into something greater than we are now.
I agree with the majority of the opinions here, that this is really rather bogus. First, it is based on this hypothesis of a "Great Filter" event, which is unproven.

It also is kind of depressing - hoping that life isn't found elsewhere as some sort of glimmer of hope that humans will survive. It comes across and weird, stupid, and grasping at straws. Frankly, I rather hope we are not alone in the universe.
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Old 01-May-2008, 05:10 PM
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The religious zealots need to know it so they'll stop harping about how 'special' humans are. I mean, if God(s) made us in His/Her/Their own image, then who made the Greys?
Most Christian theologians don't beleive that "in God's image" means that God looks like us, but that our minds look more like His than those of any other animal - with the capacity for rational thought and imagination.
So the typical Christian's answer would be "God made the Greys too, and they are also in God's image."
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Old 01-May-2008, 05:44 PM
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I note that this opinion piece is based on the speculation of finding only evidence of the former existence of life forms - their corpses, as it were. Certainly if we only found dead things and signs of destroyed civilizations we might have cause to wonder just how dangerous the universe really is. If we found living organisms on Mars or Europa, or actually encountered living intelligent aliens it would be a different story.
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Old 01-May-2008, 06:03 PM
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The great assumption is that advanced civilizations will remain in material form. It could be that very advanced minds necessarily migrate to some kind of virtual environment and continue the quest for the Final Truth [which seems to be what intelligent beings do] as tenous pulses of energy. The only material need would be the 'server' in a remote corner of a run-of-the-mill planet that would host the virtual mind-beings. They wouldn´t be noticed as a material presence in anywhere else. That would solve the Fermi paradox and do away with the 'Great Filter'. This concept has been already explored in many SF stories, and I don´t see any reason why it couldn´t be.

Edit: Bolstrom, as a 'transhumanist', should have thought about that, but the idea is absent from his essay.
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Old 01-May-2008, 06:48 PM
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The great assumption is that advanced civilizations will remain in material form. It could be that very advanced minds necessarily migrate to some kind of virtual environment and continue the quest for the Final Truth [which seems to be what intelligent beings do] as tenous pulses of energy. The only material need would be the 'server' in a remote corner of a run-of-the-mill planet that would host the virtual mind-beings. They wouldn´t be noticed as a material presence in anywhere else. That would solve the Fermi paradox and do away with the 'Great Filter'. This concept has been already explored in many SF stories, and I don´t see any reason why it couldn´t be.

Edit: Bolstrom, as a 'transhumanist', should have thought about that, but the idea is absent from his essay.
Material form for has many advantages, for example you don't kapoot when the power goes out. Besides to keep the machinery operating you would need an army of robots to mine the resources to keep things nifty. And such activity would leave traces, that we don't see. So uploaded mega-god type civilizations don't alleviate the paradox.
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Old 01-May-2008, 07:52 PM
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Besides to keep the machinery operating you would need an army of robots to mine the resources to keep things nifty. And such activity would leave traces, that we don't see.
Well, such activity wouldn´t necessarily leave traces that could be detected [by people like us] on the order of parsecs [let alone the fact that such activities would presumably be carried out with a high efficiency, with minimum energy requirements]
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Old 01-May-2008, 11:53 PM
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From the article:

I agree with the majority of the opinions here, that this is really rather bogus. First, it is based on this hypothesis of a "Great Filter" event, which is unproven.

It also is kind of depressing - hoping that life isn't found elsewhere as some sort of glimmer of hope that humans will survive. It comes across and weird, stupid, and grasping at straws. Frankly, I rather hope we are not alone in the universe.
It also involves coming to sweeping conclusions based on scant evidence.
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Old 02-May-2008, 03:09 AM
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Well, such activity wouldn´t necessarily leave traces that could be detected [by people like us] on the order of parsecs [let alone the fact that such activities would presumably be carried out with a high efficiency, with minimum energy requirements]
For that matter, flesh and blood aliens going about their daily business
may not either. We ourselves couldn't detect us. To me Fermi's paradox means that life is even more precious then it seems. Also, we talk of solar system, and star fairing peoples, but does a single planet have the resources to develop the infrastructure to plunder the vault of heaven? Sure it happens all the time in science fiction, but so far we haven't done squat in that direction, and sadly show no signs of doing so. We have done much research, and that is admirable, but it feeds and clothes no one.
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Old 02-May-2008, 04:05 AM
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Thank you ToSeek for that great link. I am very surprised at the negative response on this forum of the best theory (that I have seen in years) of why we see no evidence of alien life. I have very great respect for the opinions on this forum, the place I come to for comfort. LOL. Seems to me that most of the negative responses were of misinterpretations of what was intended?? I think that ravens_cry has one of the best answers to this theory “but does a single planet have the resources to develop the infrastructure to plunder the vault of heaven?” I was really feeling stupid until I came upon this remark. I may change my mind after rolling this story around in my gray matter for awhile. I will continue coming here for comfort!!
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Old 02-May-2008, 08:19 AM
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We have been considering the Great Filter at Orion's Arm for quite some time. Bostrom has the right ideas; there are a number of critical periods in the development of a civilisation which might filter out most, or all, potential contenders. In order for our fictional scenario to work, a scenario which has several advanced civilisations in each galaxy, we have had to imagine a Great Filter which somehow removes star-faring civilisations from the Galaxy after they have expanded for some limited period, but before they colonise the entire galaxy and set up homesteads on every rock, nook, and cranny.

One possibility is that an advanced civilisation always collapses due to warfare: internal strife, or in conflict with other nerby civilisations. Or there may be an existential threat from high technology itself- advanced automatic defences might decide to wipe out all potential enemies, or some experimental technology might backfire and destroy the civilisation in some way. But I suspect we would see evidence of this in distant galaxies. For instance an advanced civilisation might decide to build a large number of superweapons, such as the so-called Nicoll-Dyson Laser
http://en.wikipedia.org/wiki/James_D...ll-Dyson_Laser
which could wipe out a solar system in a single blow. If an advanced civilisation had too many such weapons they might run the risk of an accidental war. Because of light speed delays all the potential targets could be destroyed by beams emitted by lasers which are subsequently destroyed themselves.

But if such energetic warfare occurs frequently we would surely see the evidence in distant galaxies. Perhaps that is the explanation for the anomalously bright gamma-ray burst seen recently...

Another possibility is that very advanced civilisations remove themselves from our universe and create artificial universes of their own; some cosmologists think that it may be possible to create new universes in the laboratory, and perhaps tune them to be more suitable for intelligent processes. If you can make your own paradise, why stay in this cosmos where stars and planets are so far apart? When I am feeling hopeful, I tend to favour this explanation. Perhaps these advanced civilisations in their basement universes have a way of communicating with our own world when necessary; perhaps not. A daunting thought.

But most of the time I tend towards thinking that civilisations are very rare, and the Filter is in our past.

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Old 02-May-2008, 02:02 PM
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We have been considering the Great Filter at Orion's Arm for quite some time. Bostrom has the right ideas; there are a number of critical periods in the development of a civilisation which might filter out most, or all, potential contenders.
I disagree that Bostrom has the right ideas, of course.
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But most of the time I tend towards thinking that civilisations are very rare, and the Filter is in our past.
That's the big mistake that Bostrom makes. There is no such thing as a Great Filter that exists only at a single critical juncture. We have plenty of evidence that it does not--our own earth fossil record shows all sorts of time lines and possibilities. We all are aware of the possibility of our own annihilation that could occur if a large body impacted the earth, or would have occurred had the impact already have happened, for another instance.

Assuming that a Great Filter is either in our past, or in our future, but not both, is a horrible mistake. By that, I mean first that it is a totally unsupported assumption, and second there is a lot of evidence to the contrary.
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Old 02-May-2008, 03:48 PM
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If we assume that there is no one Great Filter, that seems to imply that there are lots of 'little filters', which are somewhat less difficult to get through. Or that there are lots of little filters in the past, and perhaps just one big one in the future of a civilisation like ours.

Whichever is the case, it seems likely on the evidence available that there are no billion-year-old interstellar civilisations in our galaxy.

Whether that is the end result of an accumulation of slightly dangerous filter episodes or the result of one big dangerous episode (the GF) which consistently prevents such a civilisation from forming, is open to debate. If we are past that one big filter, then that is a good thing.
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Old 02-May-2008, 03:52 PM
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I disagree that Bostrom has the right ideas, of course.That's the big mistake that Bostrom makes. There is no such thing as a Great Filter that exists only at a single critical juncture.
I totally agree. I think he is in error to talk about a single Great Filter.

He is right when he talks about filters being critical points that must be passed for life to move on to a new form or level of complexity. However rather than a single Great Filter we should see instead an accumilation of critical filters. The emergence of complex single cells was just one that had to be passed and maybe on very few worlds life gets beyond this point. Likewise the move to multicellular life might be another critical filter which life on many planets fails to progress beyond.

I think he is also to ready to dismiss the emergence of intelligent hominids as though that happened so quickly it was almost inevitable. I believe that here he has overlooked some crucial factors. Maybe once a large brained, social, omniverous, ape like mammal with versitile hands had evolved then it was perhaps that the road to humans was fairly quick and inevitable. However that particular combination of factors had to come together in a precursor species which itself needed to be forced to adapt by environmental change but was not challenged by such a severe environmental challenge that it became extinct. Big brains without the physical means to make and manipulate tools do not make technological species. Likewise manipulatorary appendages without the memory and processing power to direct them in new directions will also produce nothing new. I strongly suspect that having all of these factors come together at the right time could itself be quite a rare event and could therefore be yet another critical filter. Other factors also need to come into play does the species live long enough to pass its knowledge on to the next generation and does it take any role in raising of that next generation. If not then each generation will start from "square one" unable to build upon the knowledge and skills of its parents.

Now of course once again we only have our earthly sample of one to draw on. But assuming we are trying to identify the critical hurdles that must be overcome for the existence of a technological species anywhere then they too must achieve the combination of processing ability, memory and manipulation in order to invent and use tools for the advancement of technology. We must also accept that while we cannot predict how an intelligent alien species might view us, view each other or view the universe as a whole it is only fair to assume the purely biological processes that lead to natural selection and speciation are as similar on their planet as the chemistry that seems common across the universe. Therefore for a technological species to emerge elsewhere they need not have two sexes or have lived in trees or have hairy bodies but they must be able to store and retrieve large quatities of information about their natural surroundings and not only have the ability to imagine alternative ways of doing things they must have a suitable body form that allows them to turn their ideas into something physical. If no one species evolves with all of those then it will remain as just part of it's planet's wildlife and will produce no civilisation.
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Old 02-May-2008, 04:02 PM
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Part of the problem with "where are they?" is the idea that we should be able to detect them if they're out there. What we're looking for - radio signals, signs of mega-structures - are based on what we view as plausible extensions of our own technological development, but who is to say that our guesses are anywhere near accurate? Perhaps the galaxy is full of data transmissions using a method we have yet to discover. Maybe future breakthtroughs make the expense of mega-structures unnecessary. Perhaps the technoloy of other civilizations goes in a completely different direction from our own, in unguessed-of directions.
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Old 02-May-2008, 04:12 PM
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Yeah. With only 100 years of meaningful technology, it looks like aguing for a 'great filter' as some extension of known technologies going out of control is somewhat hasty on our part. Remember the their-technology-would-look-like-magic thing.
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Old 02-May-2008, 04:26 PM
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The worst case scenario would be that we explore the Galaxy and find no living civilisations, but lots of dead ones. That would indicate that an advanced civilisation has a limited lifespan.

That may be the point that Bostrom and his associates are trying to determine- how long can we expect a civilisation to exist?
If they are common, but short-lived, what causes that limited lifespan? And how can we avoid it?
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Old 02-May-2008, 08:28 PM
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Quote:
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That's the big mistake that Bostrom makes. There is no such thing as a Great Filter that exists only at a single critical juncture.
I totally agree. I think he is in error to talk about a single Great Filter.
Well, in the last page of the article he does say:

Quote:
Nothing in the preceding reasoning precludes there being steps in the Great Filter both behind us and ahead of us. It might be extremely improbable both that intelligent life should arise on any given planet and that intelligent life, once evolved, should succeed in becoming advanced enough to colonize space.
I see other flaws in his reasoning, though. One is what eburacum said above:

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Originally Posted by eburacum45 View Post
Bostrom is a profound thinker, but I think that his suggestion that finding dead vertebrates on Mars would be Bad News is going a little too far. The fact that Mars might have supported complex life that then died out has no real relevance for the Earth- that planet is entirely different in many characteristics to our own, so may be intrinsically more likely to become a dead planet.

A dead Mars with fossils doesn't imply anything about the existence of a Great Filter that eliminates intelligent life on Earth-like worlds.
Mars is a good example, because it shows that Bostrom neglected a little hastily the differences between planets. Some life-bearing planets may well be more hospitable to life than others.

On page 5 of the article there is another assumption which seem questionable.

Quote:
Consider the implications of discovering that life had evolved independently on Mars (or some other planet in our solar system). That discovery would suggest that the emergence of life is not very improbable. If it happened independently twice here in our own backyard, it must surely have happened millions of times across the galaxy.
Or it might mean that the chemical composition, or some other characteristic of our solar system (such as the low eccentricity of all major planets), are especially favorable to life. It seems a mistake to me to treat Earth and Mars as two independent data points. More likely, they are correlated. There's even the possibility of panspermia: that life could have arisen first in only one of these planets, and then migrated to the other.

And on page 4 there's something else I'd question:

Quote:
[...] even if most advanced civilizations chose to remain nonexpansionist forever, it wouldn't make any difference as long as there was one other civilization that opted to launch the colonization process: that expansionary civilization would be the one whose probes, colonies, or descendants would fill the galaxy. It takes but one match to start a fire, only one expansionist civilization to begin colonizing the universe.
He's assuming that the more expansionist civilisation will always triumph. But perhaps the opposite is what tends to occur: when one civilisation tries to colonise other solar systems, the colonised ally themselves to neutralise the coloniser, and stop the expansion.

Food for thought, nonetheless...
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Old 02-May-2008, 10:40 PM
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Whichever is the case, it seems likely on the evidence available that there are no billion-year-old interstellar civilisations in our galaxy.
That's speculation. In order to draw conclusions based on our very limited data, you would have to make some specific assumptions about what a civilization should do.
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Old 03-May-2008, 09:40 AM
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Whichever is the case, it seems likely on the evidence available that there are no billion-year-old interstellar civilisations in our galaxy.
Sorry, but I don't know if I must laugh or cry.
We don't know ANYTHING, how can we know how a billion year old or even 100 year more advanced civilization can behave.Period.Instead of this pseudosceptical pessimistic rants without any evidence, just so called "extrapolation" that every civilization in this part of the universe where 7x10 to the 22th power of stars reside would behave as some monkey like creatures with egomania and with predispositions to violence that can murder around 200 000 000 of their fellow people in just one century if you gave them ray guns, unlimited energy and matter and spaceships that can travel at 0.9 c, and who belive that they are the pinaccle of evolution and nature

Sorry for angry talk but I am really tired of discussing these "paradoxes" while there really aren't any and so called arguments and "predictions".
In the dawn of the 20th century, people imagined that either big war airships would endlessly battle in the air with hand loading cannons and of course, commercial airflight was "impossible" and breaking the speed of the sound with manned aircraft is a "lunatic idea", or they imagined that we would live in a utopia where noone will be hungry and people would travel to the moon using cannons and live there hapilly without any life support or spacesuits.
And do not take my comment about humans as "monkey like..." so seriously.

Btw, what do you define as intelligent civilisation, why do you assume that there is only our type of intelligence?

I think that popular scifi distorted the expectation of humanity about aliens, and instilled fear and "there are no giant gamma ray powered dyson spheres with build in planet destroyer in the sky or giant flying plate remains on Earth so no such things as advanced aliens exist, so we are the best in the universe, so we are first etc." attitudes

Last edited by m1omg; 03-May-2008 at 10:04 AM..
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Old 03-May-2008, 10:06 AM
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That's speculation. In order to draw conclusions based on our very limited data, you would have to make some specific assumptions about what a civilization should do.
I agree.But we cannot make any such conclusions without any knowledge about it, evidence.
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Old 03-May-2008, 10:29 AM
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The worst case scenario would be that we explore the Galaxy and find no living civilisations, but lots of dead ones. That would indicate that an advanced civilisation has a limited lifespan.

That may be the point that Bostrom and his associates are trying to determine- how long can we expect a civilisation to exist?
If they are common, but short-lived, what causes that limited lifespan? And how can we avoid it?
Assuming we did somehow find lots of dead civilizations, even then it could be tricky finding a common cause for limited lifespan, because we would have to generalize between (probably) very different species. Conceivably there might be a common theme, or there might be a variety of themes, some species lasting longer than others, and some continuing on. Would we be one to continue on? Who knows?
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Old 03-May-2008, 11:13 AM
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Well, in the last page of the article he does say:
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Nothing in the preceding reasoning precludes there being steps in the Great Filter both behind us and ahead of us. It might be extremely improbable both that intelligent life should arise on any given planet and that intelligent life, once evolved, should succeed in becoming advanced enough to colonize space.
Possibly added to try and answer responses such as ours

However, he still doesn't justify the remarks. That there might be aspects of the filter behind and ahead of us (we know there are) still doesn't allow him to conclude that it's "extremely improbable". Just calling it a "Great" filter doesn't mean one that it exists, and two that is actually highly improbable.

Anyway, start one billion "life experiments" (one for every few hundred suns in the Milky Way) and wait twenty billion years. What kind of result are we going to accept as "highly improbable?" I would be impressed if a thousand made it through (a map of the galaxy would look like suburban sprawl), but of course those other 999,999,000 would not be as impressed.

Regardless of what extraterrestrial evidence means for us in our unique situation.
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Old 03-May-2008, 11:24 AM
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I think that popular scifi distorted the expectation of humanity about aliens, and instilled fear and "there are no giant gamma ray powered dyson spheres with build in planet destroyer in the sky or giant flying plate remains on Earth so no such things as advanced aliens exist, so we are the best in the universe, so we are first etc." attitudes
I agree, we should try to remove all preconceptions about intelligent alien civilisations, and simply go on the evidence. This is what Bostrom tries to do, I believe.

At the moment there is merely an absence of evidence. The absence of transmissions, anomalous emissions, megastructures in the sky or archaeological, palaeontological or evolutionary evidence for aliens on Earth eliminates a whole swathe of civilisation types, which includes perhaps the type of civilisation which humanity might one day become.

It is true that the evidence does not rule out stay-at-home civilisations which limit their growth to below detectable limits; there could be a hundred billion advanced civilisations orbiting red dwarfs in our galaxy alone, secure in the knowledge that their star will last a trillion years without exploding. But as Fermi pointed out, it only requires one of those hundred billion civilisations to decide to expand their territory, and you could have a galactic civilisation.

Perhaps there is a filter of some sort which prevents that sort of expansionism? If there is, we will want to know about it before we set off on an expansion of our own.

Or do advanced civilisations decant themselves into manufactured baby universes, thereby leaving the space we can see in our telescopes empty? If that occurs, it would be an effective filter which removes evidence of civilisation. It would also probably be a benign filter, unless civilisations in baby universes fail for an unknown and perhaps unknowable reason. But then again, why should every single one of all the diverse types of civilisation that may emerge all decide to decant themselves? This would only happen if it were the only possible option, and I can't really see that being the case.

At the moment, the 'great Filter' hypothesis is only that, a hypothesis. A filter which consistently removes expansionistic and detectable civilisations would need to be an 'unexpected and subtle' one; I have no idea what that filter might be, but I too hope that it doesn't exist, and that the Great Filter exists in the past, so that we have instead already passed the most strenuous of our crisis events.
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Old 03-May-2008, 12:37 PM
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Originally Posted by eburacum45 View Post
I agree, we should try to remove all preconceptions about intelligent alien civilisations, and simply go on the evidence. This is what Bostrom tries to do, I believe.

At the moment there is merely an absence of evidence. The absence of transmissions, anomalous emissions, megastructures in the sky or archaeological, palaeontological or evolutionary evidence for aliens on Earth eliminates a whole swathe of civilisation types, which includes perhaps the type of civilisation which humanity might one day become.

It is true that the evidence does not rule out stay-at-home civilisations which limit their growth to below detectable limits; there could be a hundred billion advanced civilisations orbiting red dwarfs in our galaxy alone, secure in the knowledge that their star will last a trillion years without exploding. But as Fermi pointed out, it only requires one of those hundred billion civilisations to decide to expand their territory, and you could have a galactic civilisation.

Perhaps there is a filter of some sort which prevents that sort of expansionism? If there is, we will want to know about it before we set off on an expansion of our own.

Or do advanced civilisations decant themselves into manufactured baby universes, thereby leaving the space we can see in our telescopes empty? If that occurs, it would be an effective filter which removes evidence of civilisation. It would also probably be a benign filter, unless civilisations in baby universes fail for an unknown and perhaps unknowable reason. But then again, why should every single one of all the diverse types of civilisation that may emerge all decide to decant themselves? This would only happen if it were the only possible option, and I can't really see that being the case.

At the moment, the 'great Filter' hypothesis is only that, a hypothesis. A filter which consistently removes expansionistic and detectable civilisations would need to be an 'unexpected and subtle' one; I have no idea what that filter might be, but I too hope that it doesn't exist, and that the Great Filter exists in the past, so that we have instead already passed the most strenuous of our crisis events.
But what if very advanced civilizations can mask their achievements?
Or they exist but they are too far.
Really, think.

We are worried about our TV transmissions revealing us (even trought it is impossible), surely if they build megastructures, they can mask 'em (and they will).
And that we do not detected anything means that we do not have enough sensitive instruments.
I think advanced civilizations are laughing loudly at us on how blind we are.

We are looking for evidence of technology that envisioned we, not them.
I hate when someone says "no evidence"
This is as ridiculous as trying to see quarks with a kids microscope and then claiming that they do not exist "because there is of course no evidence".

They can build megastructures, they can be slime balls using telepathy etc...

I hate when someone think that supercivilization would be so stupid to show themselves to lesser civilizations.

Even in your scifi project OA you have these types of materials that cannot be seen, absorb all radiation, cannot be easily spotted and destroyed etc.
What do you think they would build dyson spheres if they would want to, rusty iron painted bright while to shout "Hello, we are here"?
Yes, we would be no threat to them but other civilization of the same type can cause war and on the galactic level it would be extremely cruel.
What if we are actually their experiment?
Etc....

I think that billions of years old civilization would be like God, and we like bacteria compared to them (but this do not mean that they would behave to us like we to bacteria simply because humans are not parasitic).

We really don't know anything.

I think instead of discovering "no one here" we would all get heart attack when we will discover how strange our universe and the beings inhabiting is.

We know only two things, that they would not be humans with oval heads, blue skin and forehead ridges and that we don't know anything.

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