Why we're the only intelligent life in our galaxy

[Ty]

Nitpicking, but:
There is formally no upper bound on the absolute size of the universe, just the size which we can see, and the (different) size with which we can ever interact. We believe from inflation that the absolute size of the universe is much, much larger than what we can see.

If the missing mass is found, when would expansion stop?

 

[NANOTEC]

With all of our advancement, we have not yet stopped wanting to spread ourselves and our culture. My claim is that this desire is a fundamental aspect of life, and something that isn't going to go away. Therefore, any sufficiently-advanced society is going to eventually colonize, if it doesn't kill itself off first.

Again this goes back to the question I brought up a long time ago but was never addressed. You must state your reasons why we as humans want to colonize other planets. From there we can address why other intelligent life may/may not want to colonize other planets.

We as humans look at colonization as a potential way to solve some of our problems or as a way to find answers to our questions about the universe. We cannot assume other intelligent life have the same problems or questions hence the desire to colonize other planets.

 

[nutball]

There are various papers in the literature that place an upper bound on the amount of information stored in the brain and how many calculations per second it can perform using various neurological models to count. One might be tempted to discount them, except for the fact that they have successfully used such models to place artificial neurons in lower lifeforms that record, model ( "shadow" ), and then assume the functionality of the natural ones, and the outputs agree.

The success of these techniques on small numbers of neurons (typically just a handful using nematodes which have ~300 neurons) have led IBM to attempt to build a 10,000 neuron simulator that will be used to model a small section of the human brain to test the predictive power of the neurological models.

I wasn't intending to discount the calculations, I found them interesting. The graph you presented puts 10^15 FLOPS within reach within the next few years, a value which if taken a face value would imply that we will shortly have the compute power available to simulate the workings of an entire human brain at 10^-4 real-time. This in itself would be a worthwhile achievement I think (ie. one minute of simulated time would take a week of elapsed time).

It's not clear that the simple headline FLOPpage is the rate-limiting step to such simulations becoming feasible though. I'd hazard a guess that there are numerous hardware and software barriers to overcome (the interconnect being one which seems to stubbornly lag behind compute power and can cause major headaches in extracting the headline compute power, then there's the small issue of writing a code which scales to millions of processors). I also wonder whether enough is known about the structure of the brain on all the relevant scales and how the various scales interact to construct a meaningful model -- but that's a statement of my ignorance not of my scepticism.

So I guess where I'm going with this is that it's not clear to me that simple extrapolation of Moore's Law necessarily gives a meaningful estimate of when such simulations might be feasible in reality. I do accept however that from the perspective of computing (hardware & software) that simulations of the relevant scale will become possible within our lifetimes.

 

[NANOTEC]

1. What's the difference between the brain of a chimp and that of a human?
2. What's the difference between the brain of a chimp and that of a 3 year old human?
3. Why are humans so much smarter than chimps? Brain size to body size ratio or something else? If it's something else what is it?

 

[nutball]

This thread is very interesting ... for more than just the subject matter.

It seems to be saying a lot about what people want to be true. It also seems to show how deeply certain ideas from science fiction have become engrained in common culture.

---
So basically ... science, either accept and acknowledge it's flaws but see what it has to tell you, or ignore it and accept that you have a faith-based world view. There's not really a half-way house.

of course - but than again to me those kind of arguments are more about the "worldview" than postulating a scientifically provable theory on why there is something or not, as it is we do not stand much chance of doing that.

What are the options: There is nothing apart from us, or there is something but not near, or there is something but does not want to show itself.

To me option #3 is most plausible.

To you the main argument is "well the probablilites have not been calculated"/ "this is unmeasurable" etc... in any case if the probability for life is >0, and if either time or space is infinite than life is a certainty, and in quantities more than 1. Even if the probability for existance of life is exceedingly small, the probabilty that we are the first/only ones is again a lot less.

What I was getting at was that there seem to be two underlying themes running through some of the posts here which I found interesting. They are:

- an reluctance to accept that we may be the only intelligent life in the galaxy
- the view that any more advanced civilization will, nay must, have a certain world-view

I think this tells us two things about mankind and our modern Western civilzation:

- we don't like being alone
- we have a very poor self-image

Humans are sociable animals, we crave company. Even if we're without human company we surround ourselves with pets. I think this makes us very feel uncomfortable when we think about being alone in the galaxy. Without life elsewhere the Universe is cold and empty, and our existence within that Universe is meaningless. If nothing else it means there's nothing neat and interesting for us to discover!

Secondly the First World is on a massive guilt-trip about how crap we are as individuals, as a society and as a species. We seem to want to assume that any more advanced civilization than us won't have our flaws. These putative advanced civilizations must, the reasoning goes, live in harmony with their environment and their neighbours, they don't have wants and needs that drive our bad behaviour. They, unlike us, have overcome their animal instincts and think is purely altruistic terms. The "global 60's hippie commune" I alluded to earlier. I think this is more a statement of what we wish to be out there and what we think we ourselves should be. Admitting to ourselves that we may well be the most intelligent and advanced civilization in the galaxy, that we are as good as it gets, I don't think this sits well with our apparent need to feel bad about the stuff we do today.

 

[KimB]

If the missing mass is found, when would expansion stop?

The expansion of the universe is speeding up. It's unlikely that the expansion will ever stop because of this. As for the soonest possible experimental bounds in an absolutely extreme scenario? About 15 more doublings of the scale factor (i.e. the universe would have to double in size 15 times over before the expansion stopped), which is roughly 10^13 years. But that's a really extreme scenario.

Edit:
Finding "missing mass" isn't the issue, though. It's what happens with the dark energy, as well as what the actual curvature of the universe is that together determine the fate of the Universe. All evidence points to exponentially-increasing expansion.

 

[KimB]

Again this goes back to the question I brought up a long time ago but was never addressed. You must state your reasons why we as humans want to colonize other planets. From there we can address why other intelligent life may/may not want to colonize other planets.

We as humans look at colonization as a potential way to solve some of our problems or as a way to find answers to our questions about the universe. We cannot assume other intelligent life have the same problems or questions hence the desire to colonize other planets.

Discussed this a while ago, and I don't think I can say it any better again:
http://www.beyond3d.com/forum/showpost.php?p=747962&postcount=100

 

[NANOTEC]

Discussed this a while ago, and I don't think I can say it any better again:
http://www.beyond3d.com/forum/showpost.php?p=747962&postcount=100

So this "human culture" that has the "desire to spread" somehow arbitrarily applies to any other intelligent alien culture?

What you're saying is analogous to "We as a human race have a natural tendency to be greedy therefore we must assume other intelligent life on other planets have the same tendency."....ok.

 

[nutball]

So this "human culture" that has the "desire to spread" somehow arbitrarily applies to any other intelligent alien culture?

What you're saying is analogous to "We as a human race have a natural tendency to be greedy therefore we must assume other intelligent life on other planets have the same tendency."....ok.

It's not fair to single out humans -- all species on Earth will expand (population-wise) to the limits of their ability. It seems to be a "universal law" judged by the behaviour of all the species on Earth. Whether you count that as a single sample or a few million samples is a matter for debate I suppose.

(Yes, I know that no other species on Earth are what we're defining as intelligent for the purposes of this thread, but the point is that even here on Earth being aggressive and greedy is not a uniquely human trait -- it just so happens that we're the best at it at this point in time. It's our heritage -- 600 million years of heritage!!).

 

[KimB]

What you're saying is analogous to "We as a human race have a natural tendency to be greedy therefore we must assume other intelligent life on other planets have the same tendency."....ok.

No, that's not what I'm saying. What I'm saying is that if you put civilization A that does not wish to expand next to civilization B which does, civilization B will dominate.

 

[NANOTEC]

if you put civilization A that does not wish to expand next to civilization B which does, civilization B will dominate.

Not necessarilly -> offense doesn't guarantee a victory. Defense is half the equation. Example: Civilization A travels to planet X to colonize. Civilization B on planet X in self defense destoys civilization A. Another example: Civilization A travels to planet X to colonize. Planet X is already inhabited by civilization B. Civilization A starts to colonize planet X and cohabitate alongside civiization B. Civilization A starts to die because it cannot adapt to native disease on planet X unlike civilization B who have lived there for centuries.

What you're saying is that if we were to be contacted by other intelligent life, it would likely be the colonizing type, however, since we haven't been contacted, other intelligent life doesn't exist...ok. What about other intelligent life that is not interested in colonizing? Did they just disappear into a black hole or something?

 

[Druga Runda]

Druga you are handwaving probability figures around. Neither time nor space are infinite, we have pretty good bounds on the size and age of the universe. You don't know the probabilities involved in life, so it makes no sense to pronounce that small probability * age/size of universe => implies high probability of more than one life event. You could be talking about numbers whos exponents differ by dozens of orders of magnitude.

true, this is why such a statement is not really scientifically acceptable, but just looking at the abuncance of life that has permeated this planet in this solar system of ~4.5 bn years age, it is not such a large stretch to imagine billions earth like systems (one estimate was 30 billions in Milky Way) even in our own galaxy which is estimated at about ~14bn years old, giving us more than double the time for the same process to repeat in similar conditions on another place.

Well of course that numbers are too complex to be even approximated, but given that this planet is teaming with life, even at such places with no sunlight at the bottom of the ocean with an energy source helps me keep an open mind with regards to the idea of intelligent life elsewhere, even within the galaxy. Or something like this.

Even infinite time or space doesn't save you.

Why not? Moreso it gives it infinite occurances. Same conditions no matter how unlikely the odds might be, given enough time they will produce same result again and again I think this is a logical argument.

The idea that there is something near, but doesn't want to show itself appears to be based purely on belief. Why is it the most plausible? But what basis do you claim life is more likely to be nearer but hidden, than far outside our light cone? On what basis should it be so clustered together?

Basis? Well on the basis that there is life, that it seems to be abundant on this planet, that some scientists even hoped for other primitive lifeforms even in the rest of the really hostile solar system, let alone on billions of earth like planets in our galaxy or possibliy infinite number in the whole universe.

This is where I think the frustration comes in, because alot of implicit and non-supported (faith-based) arguments get thrown around.

Either you have a rational argument for why it is true, or you have evidence, but you "gut feeling" is not sufficient.

Implicit arguments? Well abundance of life here is followed by the ?implausible? conclusion that there might be likely abundance of life under similar conditions elsewhere, even given 30 billion attempts and twice the time in our own galaxy.

The conclusion being implausible only because the other presumably more advance life forms did not either settle here already in friendly environment, or did not come to greet us and tell us "hello, let us teach you how you need to live your life better"?

No, that's not what I mean. I mean that if we take planet X, upon which some intelligent species could someday evolve if left alone, the colonization of planet X by some other intelligent species Y will alter the evolution on planet X so that a new intelligent species cannot evolve.



With all of our advancement, we have not yet stopped wanting to spread ourselves and our culture. My claim is that this desire is a fundamental aspect of life, and something that isn't going to go away. Therefore, any sufficiently-advanced society is going to eventually colonize, if it doesn't kill itself off first.

well with this one we go into more sociological argument, of what the "advanced society" is like, is it more like ours today or "different".

Well my argument for "different" is twofold. Firstly comparing our todays society with the one 8 thousand years ago, it is undoubtebly more refined, more caring overall (like the tsunami response, beginnings of environmental awareness etc). While for prehistory 8k years ago one could argue that it was very evolutionary, ie fittests survives, kills the weaker, etc... Going forward you have more social awarenes together with progress... for example we today do not enjoy gladiatiors in arena killing each other like in relatively developed Roman times, instead we watch football. I think a good argument could be constructed that more developed society is more "integrated" it becomes into the environment and less predatory it is. Thus it is fair to assume that with ups and downs it will go towards integration and not colonization as it was in the past.

The second argument is that a "predatory" society will periodically produce individuals such as Hitler who will not have the moral responsibility towards anyone and will use all the power in their hands to do as they see fit resulting in destruction. More technologically advances such society is more likely is that such a person is fatal for the whole civilization. Thus after a few cycles the civilization either self destructs or becomes integrated with one another and the environment, at the core. Think about it like the "fittests survives" but in this case the fittest civilization is the one who does not spawn "self-destruction ready" individual, as techologically all advanced civilizations will be capable of self desctruction quite easily. Even today we have multiple choices to execute it, either nuclear or biological. Assuming that such a catastrophe happens - imagine a Hitler in 100 years executing viral warfare, and the civilization is decimated but survives it is bound to profoundly affect the remaining individuals and push it into a different direction. IF one cycle is not enough I am pretty certain that it will be either one or another. Even looking around our earths cultures the more peacefull ones to this point were not served by their unwilligness to be good warriors as it was necessary to succed, but in the future this different trait will be essential for survival, as the battle for resources might not be the most important one in our future. - for example - harvesting fusion, with enough efficiency together with nanoengineering might eliminate this problem.

Sure, but as I've said previously, it's much easier to make use of an already-habitable biosphere than worry about artificially creating one (except for the possible exception of planets within the same solar system). It will take a lot of time and natural resources to terraform a planet, and much more in the way of resources to generate a biosphere from scratch.

Well, I claim only ones in our galaxy. That doesn't mean there aren't others in other galaxies, so far that they could never have reached us.



But option #3 makes no sense except in the obscenely-unlikely scenario where the intelligent species is within about 50-100 light years. Only in being that close could they have possibly detected our existence as an intelligent species. And they would also have had to evolve intelligence at almost the exact same time as us for them to not already be here.





Sure. Just bear in mind that the observable universe is finite. The universe with which we have a chance of ever interacting is actually smaller (due to the accelerated expansion), and the universe with which we ever have a practical chance of physically meeting extraterrestrials is even smaller.

following on the arguments above...

on #1 in this last quote - I assume that the technologically advanced civilization, and we speak here about millions of years past us, such problems will be trivial, like forexample flying is trivial for us today while it was impossible even for relatively advanced (comparing with their predecessors) ancient Greeks.

on #2... if universe physics allow FTL, or even some more exotic eventualities like space bending, dimensional travel etc... than whole universe comes into the equation

on #3 ... I think this one follows your "if they could be here they already would be" logic, with which I disagree

on #4 ... I agree that the observable universe is finite, but if the conditions permitting life development are infinite, and FTL, other more exotic ideas are permittable in this universe than even that will not be a problem.

--- I will come back to the others later as I am going to the cinema now

 

[Frank]

Why are most contributors here assuming that humans as they exist today are the highest lifeform possible that evolves on Earth? I think that's very unlikely. And while we might differ about the direction it will take (computers, "cyborgs", virtual environments, newly designed biological post-humans or something else entirely), I would be extremely surprised if humans as they are today would survive the next thousand years unaltered, or at all.

Just egocentric thinking?

 

[nutball]

Well of course that numbers are too complex to be even approximated,

Correct.

but given that this planet is teaming with life, even at such places with no sunlight at the bottom of the ocean with an energy source helps me keep an open mind with regards to the idea of intelligent life elsewhere, even within the galaxy.

It's not a question of open mind or closed mind, it's a question of irritation with the statement "it is likely that there is life elsewhere"! That is a probabilistic statement, it only has any meaning if you have a handle on the probability involved. Without a firm handle on the probability you are simply stating "I believe".

Look it's quite simple: we have one piece of information constraining the probability of life evolving on a planet -- that it is non-zero. That's it. That's all we know. It could be 0.9, it could be 10^-20. If it's the latter then your 30 billion Earths don't help you at all, they tell you that we're an unlikely accident.

The argument about life on Earth existing in hostile places is also spurious -- it shows that life can exist in such places, it does not necessarily demonstrate that can be created in such places.

 

[nutball]

Why are most contributors here assuming that humans as they exist today are the highest lifeform possible that evolves on Earth?

I don't think anyone is.

I would be extremely surprised if humans as they are today would survive the next thousand years unaltered, or at all.

Why not? We've coped just fine for the thick end of a million years so far. More bad self-image?

 

[Frank]

Why not? We've coped just fine for the thick end of a million years so far. More bad self-image?

No, I'm not suggesting that we couldn't do it as such, just that we will change, replace ourselves or will be replaced. Probably a combination of the first two.

 

[DemoCoder]

It it difficult to imagine a species capable of reasonably speedy interstellar travel in "ships" that is confined to just one planet. If human beings started launching interstellar ships everywhere, the resources of the earth would be depleted even faster.

A stay-at-home species which launches automated probes is a different story.

 

[Frank]

It it difficult to imagine a species capable of reasonably speedy interstellar travel in "ships" that is confined to just one planet. If human beings started launching interstellar ships everywhere, the resources of the earth would be depleted even faster.

And we would change either way, adapt or be adapted to the different environments on other planets/habitats, and likely even here at home. Like, being born with an uplink to the internet and some extra on-line memory.

A stay-at-home species which launches automated probes is a different story.

Or just stay at home without sending probes. Either way, it solves the Fermi paradox rather nicely.

The chances of there being an agressively expansive species close by that sees the Earth as a good habitat is extremely small, unless you expect humans or alike lifeforms to Terraform the whole Galaxy to have enough room to reproduce. And even then it would be executed by remote automation, with some small spots of biological life.

 

[DemoCoder]

And we would change either way, adapt or be adapted to the different environments on other planets/habitats, and likely even here at home. Like, being born with an uplink to the internet and some extra on-line memory.

You're just repeating my post-humanist arguments. I take it as a given that biological humans won't exist in several hundred years, and it was asserted in the beginning of this thread.

Or just stay at home without sending probes. Either way, it solves the Fermi paradox rather nicely.

No, unless you have a population of 1. A sufficiently advanced civilization puts the power of space exploration in the hands of individuals. If you have billions of intelligent life forms, and universal molecular assemblers, all it takes in one interested hacker to create a probe.

Your model requires all species to be borg-like species of a single mind. Otherwise, sheer chance would dictate that atleast some individuals of some species would desire to explore outside the planet, and would have the means to do it.

One of the fundamental properties of evolution is that it fills all spaces it can, whether in physical geology, or in information space. You propose that a universe teeming with individuals comes to a collective consensus, and there are no defectors or mutant memes. It just doesn't wash and it doesn't solve the Fermi Paradox.

The Fermi Paradox is best solved by assuming that intelligent life is actually incredibly rare. So rare that either it doesn't exist, or the closest intelligent species is forever beyond our lightcone.

 

[KimB]

Not necessarilly -> offense doesn't guarantee a victory. Defense is half the equation. Example: Civilization A travels to planet X to colonize. Civilization B on planet X in self defense destoys civilization A. Another example: Civilization A travels to planet X to colonize. Planet X is already inhabited by civilization B. Civilization A starts to colonize planet X and cohabitate alongside civiization B. Civilization A starts to die because it cannot adapt to native disease on planet X unlike civilization B who have lived there for centuries.

My argument wasn't discussing space travel, just how the cultures of a planet would interact with one another prior to it. And your argument is an absurd what if in this scenario, because such an interaction would be, by definition, between a large number of very diverse cultures. You can't have just two on a planet, and so the probabilities become extreme. It's like statistical mechanics: the random movement of many atoms leads to completely predictable behavior.

And finally, it's the civilization that likes to colonize that is more likely to be immune to a given disease, as it will have by definition interacted with more civilizations.

What you're saying is that if we were to be contacted by other intelligent life, it would likely be the colonizing type, however, since we haven't been contacted, other intelligent life doesn't exist...ok. What about other intelligent life that is not interested in colonizing? Did they just disappear into a black hole or something?

At most I could accept the possibility of one or two such civilizations. I think our experience on Earth seems to indicate that most civilizations will want to colonize (space exploration is a multinational, multicultural effort), so if we took many planets with intelligent life at random, I would expect the vast majority to want to colonize their local area.

But just for the sake of argument, let's say that the chance for an intelligent society to begin colonization is 75% (I think it's vastly higher, personally). My argument rules out the possibility of one other intelligent society with a confidence level of 75%. It rules out the possibility of two others with a confidence level of 93.75%. Three at 98.4%. Four at 99.6%.

So what I'm say is that if you have more than one intelligent society existing before us in this galaxy, the probability that at least one of them will not have started colonization becomes so vanishingly small that it seems obscenely unlikely. And so this argument requires that intelligent life either be rare, or that the right conditions for it to arise have only recently come to be.