The Fermi Paradox and probability theory.

[Mouthwash]

It's from 2008, but still very interesting:

Where are they? - Why I hope the search for extraterrestrial life finds nothing.

The observable universe contains on the order of 100 billion galaxies, and there are on the order of 100 billion stars in our galaxy alone. In the last couple of decades, we have learned that many of these stars have planets circling them; several hundred such "exoplanets" have been discovered to date. We have every reason to believe that the observable universe contains vast numbers of solar systems, including many with planets that are Earth-like, at least in the sense of having masses and temperatures similar to those of our own orb. We also know that many of these solar systems are older than ours.

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. The filter consists of one or more evolutionary transitions or steps that must be traversed at great odds in order for an Earth-like planet to produce a civilization capable of exploring distant solar systems. You start with billions and billions of potential germination points for life, and you end up with a sum total of zero extraterrestrial civilizations that we can observe. The Great Filter must therefore be sufficiently powerful--which is to say, passing the critical points must be sufficiently improbable--that even with many billions of rolls of the dice, one ends up with nothing: no aliens, no spacecraft, no signals.

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.

 

[BvBPL]

I don't see the Great Filter hypothesis as being likely at all relative to other hypotheses about why we have not contacted ALFs. The idea doesn't make sense. The idea of a universal biological cut off switch that is based on the relative technological development of the culture in question is absurd. Vogon constructor fleets seem just as likely and more poetic.

 

[Mouthwash]

I don't see the Great Filter hypothesis as being likely at all relative to other hypotheses about why we have not contacted ALFs. The idea doesn't make sense. The idea of a universal biological cut off switch that is based on the relative technological development of the culture in question is absurd. Vogon constructor fleets seem just as likely and more poetic.

Thank you for this completely useless post. Please feel free to excuse yourself from the thread.

 

[Core Imposter]

Seems like solid thinking.

 

[El_Machinae]

I quite like Nick Bostrom. He wrote the Fable of the Dragon Tyrant, which I've linked here (the youtube reading of it anyway) and he has a bunch of great ideas.

Now, his 'great filter' idea only really fits with Solar exploration (Mars, etc.) because there needs to be a comparison between the 'odds' of early life and the 'odds' of old life in order to construct the Filter concept. We have no idea regarding the probability of distant microbes.

 

[Mouthwash]

I quite like Nick Bostrom. He wrote the Fable of the Dragon Tyrant, which I've linked here (the youtube reading of it anyway) and he has a bunch of great ideas.

Now, his 'great filter' idea only really fits with Solar exploration (Mars, etc.) because there needs to be a comparison between the 'odds' of early life and the 'odds' of old life in order to construct the Filter concept. We have no idea regarding the probability of distant microbes.

Why is that?

 

[El_Machinae]

Why is what? With regards to distant life, we have no idea if the 'Filter' is occurring during early life or during civilization. We have no datapoints. We'd need to see the number of distant early life in order to asses the odds of the filter being behind or ahead of us.

 

[Mouthwash]

Why is what? With regards to distant life, we have no idea if the 'Filter' is occurring during early life or during civilization. We have no datapoints. We'd need to see the number of distant early life in order to asses the odds of the filter being behind or ahead of us.

Isn't that what he's saying?

 

[warpus]

I'm not surprised that we haven't seen a sign of intelligent life out there - the universe is a huge place.

What if there's only 4 or 5 intelligent civilizations per galaxy? It's possible that our entire civilization dies out before we ever learn of those 4 or 5 other civilization in our very own galaxy..

And if what if the numbers are even smaller?

I don't really see the Fermi paradox as a paradox. It's an apparent paradox. As for the great filter, he may be onto something, in a way. Conditions have to be right for civilizations and species to advance" to the next level". I wouldn't quite frame it the way he did though.

 

[LamaGT]

I think there's just a lot more factors counting towards developing galactic civilizations. Just think of what myriad of factors were required to develop the puny space faring capabilities we have now, even though our biological intelligence level is the same as 35000 years ago. Then think of how far we are from interstellar travel, and add it up to the fact that we're a needle in a haystack of stars and that even if they found us, aliens might have been kind enough to leave us alone following something like the prime directive.

I think he dismisses this way too easily and for some reason gets the conclusion unlikely=impossible.

 

[Ziggy Stardust]

The article forgets the time factor. Aliens visited a million years ago (blink of an eye) found life, but not intelligent and moved on. It also dismisses that the Universe is a bit big. If the speed of light is indeed a barrier, odds are immense that alien civilisation will never meet because they are isolated.

 

[Daird]

I quite like Nick Bostrom.

I used to agree. Then I heard about the Simulation Hypothesis, which quite frankly makes him sound like a nutcase. The Matrix was a great movie, but nothing more.

 

[El_Machinae]

Isn't that what he's saying?

Yes. And it becomes relevant when we go looking for life on Mars (etc). A null result is (technically) good news, of course, Terran-based life on Mars wouldn't affect the hypothesis.

I used to agree. Then I heard about the Simulation Hypothesis, which quite frankly makes him sound like a nutcase. The Matrix was a great movie, but nothing more.

! I thought it was pretty amusing! The question "what if we're God's dream?" is a fairly old one, but this is a new take on the idea. And, honestly, it raises interesting questions about odds.

 

[warpus]

The article forgets the time factor. Aliens visited a million years ago (blink of an eye) found life, but not intelligent and moved on. It also dismisses that the Universe is a bit big. If the speed of light is indeed a barrier, odds are immense that alien civilisation will never meet because they are isolated.

Say there's only 1 sophisticated space-faring civilization per galaxy. That's still hundreds of billions of alien civilizations in the universe. And if each one is in a different galaxy it's not inconceivable that not many of them would be able to develop technology capable of contacting, visiting, or even locating any of the other civilizations.

And maybe life and sentient space-faring civilizations are even more rare than that? The universe would still be "teeming" with life sort of since it'd have millions or billions of species of intelligent life sprinkled throughout.. but they'd be so far apart that they would never even locate eachother. What a depressing thought..

Either way you're right, we have no idea how common life and space-faring civilizations are. There could be a lot of them out there and be unreachable or even undetectable. The paradox isn't there if you consider all the possibilities.

 

[Mouthwash]

I'm not surprised that we haven't seen a sign of intelligent life out there - the universe is a huge place.

What if there's only 4 or 5 intelligent civilizations per galaxy? It's possible that our entire civilization dies out before we ever learn of those 4 or 5 other civilization in our very own galaxy..

And if what if the numbers are even smaller?

I don't really see the Fermi paradox as a paradox. It's an apparent paradox. As for the great filter, he may be onto something, in a way. Conditions have to be right for civilizations and species to advance" to the next level". I wouldn't quite frame it the way he did though.

I think there's just a lot more factors counting towards developing galactic civilizations. Just think of what myriad of factors were required to develop the puny space faring capabilities we have now, even though our biological intelligence level is the same as 35000 years ago. Then think of how far we are from interstellar travel, and add it up to the fact that we're a needle in a haystack of stars and that even if they found us, aliens might have been kind enough to leave us alone following something like the prime directive.

I think he dismisses this way too easily and for some reason gets the conclusion unlikely=impossible.

The article forgets the time factor. Aliens visited a million years ago (blink of an eye) found life, but not intelligent and moved on. It also dismisses that the Universe is a bit big. If the speed of light is indeed a barrier, odds are immense that alien civilisation will never meet because they are isolated.

This is to all of the above- simply because I quote sections from a link to give you some idea of what it's about doesn't mean you get to comment without reading the thing at all. If it's that hard on your poor little brains, you should have known better than to post on a thread involving science at all.

Yes. And it becomes relevant when we go looking for life on Mars (etc). A null result is (technically) good news, of course, Terran-based life on Mars wouldn't affect the hypothesis.

I still can't understand your objection.

! I thought it was pretty amusing! The question "what if we're God's dream?" is a fairly old one, but this is a new take on the idea. And, honestly, it raises interesting questions about odds.

I really don't understand the simulation hypothesis. For starters, Bostrom needs to stop acting like this is some once-a-century, palpably original theory on How The Universe Works. (Greg Egan is better at those.) I could have thought it up myself pretty easily with the right combination of reading material and daydreaming.

Now what seems odd to me is that Bostrom fails to take into account the basic probability of experiencing anything as an observer. Why should something with a similar degree of consciousness be part of a different reference class? It seems the real question, given that the amount of observers experiencing 'real' phenomena is always (in a general sense) going to outstrip those experiencing simulated phenomena, why we would find ourselves in a simulation as humans on a primitive scale at all.

 

[Ziggy Stardust]

simply because I quote sections from a link to give you some idea of what it's about doesn't mean you get to comment without reading the thing at all.

Watch me.

 

[El_Machinae]

I still can't understand your objection.

It's not an objection, merely a comment on the utility of the concept

I could have thought it up myself pretty easily with the right combination of reading material and daydreaming.

I felt that way when I was being taught calculus! I mean, that's what all really fun mental exercises are .... something that seems intuitive after it has been explained. You still get credit for articulating an idea

Now what seems odd to me is that Bostrom fails to take into account the basic probability of experiencing anything as an observer. Why should something with a similar degree of consciousness be part of a different reference class? It seems the real question, given that the amount of observers experiencing 'real' phenomena is always (in a general sense) going to outstrip those experiencing simulated phenomena, why we would find ourselves in a simulation as humans on a primitive scale at all.

No, the idea is the opposite of that. The idea is that it's pressingly easy for the number of simulated observers to vastly out-number the 'real' observers.

 

[onejayhawk]

I'm not surprised that we haven't seen a sign of intelligent life out there - the universe is a huge place.

What if there's only 4 or 5 intelligent civilizations per galaxy? It's possible that our entire civilization dies out before we ever learn of those 4 or 5 other civilization in our very own galaxy..

And if what if the numbers are even smaller?

I don't really see the Fermi paradox as a paradox. It's an apparent paradox. As for the great filter, he may be onto something, in a way. Conditions have to be right for civilizations and species to advance" to the next level". I wouldn't quite frame it the way he did though.

Have you tested your assumptions?

For example, granting the existance of a single example introduces a random variable, which generates a probability distrobution. So there is a non zero probability for any appropriate space/time volume to generate that grade of life. Integrating that over all space produces large numbers. The time scale is such that you have to assume it never leaves its point of origin or that it is everywhere.

As Douglas Adams would have it, we have a really hot cup of tea.

J

 

[Mouthwash]

No, the idea is the opposite of that. The idea is that it's pressingly easy for the number of simulated observers to vastly out-number the 'real' observers.

He argued that the odds of being a human in a pre-singularity era would be lower than those of being in a similar simulation because of the extremely low amount of observers (pre-singularity humans) there would be. This ignores the fact that being in a simulation like that is incredibly unlikely anyway. Which supports the Doomsday Argument, I guess, or religion.

 

[classical_hero]

The article forgets the time factor. Aliens visited a million years ago (blink of an eye) found life, but not intelligent and moved on. It also dismisses that the Universe is a bit big. If the speed of light is indeed a barrier, odds are immense that alien civilisation will never meet because they are isolated.

There is zero proof of what you just said, plus space travel requires massive amounts of energy that makes it practically impossible among other factors.