The Great Filter – Are We Almost Past It? (1998)
mason.gmu.edu
mason.gmu.edu
1) The more important observation is that everything we see is a wilderness of apparently natural origins and processes, not that we have apparently not been visited.
2) No hypothesis involving choice that leads to failure to carry out self-replicating colonization can explain (1). All it takes is one small group in one sufficiently advanced species. This rules out wolves, berserkers, relinquishment, self-destruction, and so on and so forth.
Clearly something is missing or incorrect in how the pieces of the various sciences fit together to explain what we see. Some of the best reading on the subject is speculation on what it is that we don't know or the relative odds on where the present consensus is incorrect.
This raises an interesting problem : to make it as a society may require a high level of dynamism and aggression. To cope as a society (as technology becomes more potent) passivity and sensitivity may be necessary. It may be that there is no balance, and that if you have enough vim to create a technical society you will reach a point where progress becomes impossible due to progress so far.
"No alien civilizations have substantially colonized our solar system or systems nearby. Thus among the billion trillion stars in our past universe, none has reached the level of technology and growth that we may soon reach."
While the article is in a way all about exploring that disconnect, it's a bit strange to find it written down so explicitly in the conclusion. We can ascribe a very high level of confidence to hypothesis that neither our own nor any of the directly neighboring star systems have been colonized. But to postulate that therefore the universe has not yet produced a civilization as technologically sophisticated as our own is still a non-sequitur, at least in my opinion. The article also makes a lot of assumptions (it has to!), some plausible, some seemingly arbitrary, which might in the end not be important factors at all. For example, any consideration about radio communication must be on very shaky grounds, in particular when charting the absence of it.
The reason why we're not seeing alien neighbors or predecessors (which would be "neighbors" in time), might well be a combination of factors. While we can exclude certain scenarios, such as a cloud of Von Neuman Probes eating the galaxy, it still leaves room for a lot of little factors that can change the galactic stage for us in a fundamental way - especially if they work in conjunction.
For example, the average duration of the technologically recognizable phase a civilization goes through may be smaller, and there may well be less of them than expected. In addition, willful avoidance or isolation may well play a role; the zoo hypothesis is an extreme example of this, but in a sparse cosmos the measures you have to undertake in order to isolate an emerging civilizations become less heroic.
It's also worth mentioning that we ourselves are not past the Filter by any means. In fact, as time progresses, it seems to become less likely we'll ever move off the Earth as an exclusive habitat. Part of this is due to psychology, we could have made it happen by now but didn't. The best bet at becoming an interstellar civilization right now seems to be to wait until we're pure computer systems, unburdened by aging and the passage of time, but that development, too, might end up being something we never elect to actually pursue.
Luckily, this whole thing is a mystery we can solve over time, just by gathering data about what's out there.
The timescale for megascale engineering to occur throughout our galaxy as the result of the launch of one megascale engineering minded self replicating probe is small (1 million years) in comparison to the age of the galaxy (13 billion years). It is unlikely that we are sitting here while someone else is in the process of doing it; that's not the scenario to focus on.
All it takes, remember, is one small group in one sufficiently advanced culture to start this going. Some (post)human group will clearly do it at some point if we as a species continue. Why hasn't someone already done it, where "it" is visibly engineer the totality of the future light cone?
The problem is less one of why don't we see Dyson spheres and other similar type II projects within a few hundred light years of our position, and more one of why do we see no obviously altered galaxies among the hundreds of thousands cataloged to date. At this scale the zoo hypothesis looks stretched, and the simulation argument begins to look more plausible.
A partial answer to the Fermi paradox by appeal to the anthropic principle: there is a very small fraction of time between being able to observe an alien species and being consumed by it.
The need for megascale projects is not as obvious as it's sometimes made out to be. There might well be reasonable limits beyond which the maximizing of habitat space and energy consumption tapers off in utility. Even if our civilization continues on its present course, it's not certain that we will get to the point where we (or some of us) feel the need to change the face of the galaxy. If you go one step down from the galactic stage, the detectability of solar system-scale megatech is also open to debate, especially as you move beyond a couple hundred light years from here.
You're right of course when you say all it takes is one civilization (or even one member of a sufficiently advanced society) to undertake projects that are liable to make all kinds of strange phenomena appear in our night sky. But the number if beings capable of doing so on a whim, multiplied by the chance they'd be interested in such things, might be very very small without breaking any of our current expectations about biology and physics.
Finally, I'd like to address the simulation argument. There are two extreme ends of the simulation scenario spectrum.
At the one extreme, we're talking about an artificial reality made especially for us, humans. This would be the popular "Matrix"-style simulation. No scientific argument I've heard so far makes it a convincing model for the reality we live in, except as a possible explanation for the Fermi paradox.
At the other end of the spectrum, we have a full simulated universe. It's hard to argue for or against that notion, simply because either way it fits with our observable reality. The catch is of course that it's a neutral proposition with no impact on us at all. This variant does not offer any explanation for the Fermi paradox.
As I see it, the simulation argument as pertinent to the Fermi problem offers two options, neither of which are intellectually appealing: one is a borderline-untenable just-so make-believe world where all rules are an illusion and anything can happen, and the other one is virtually undistinguishable from our "normal" world, up to and including an absence of any obvious explanation for the Fermi paradox.
This is why, if I invented antimatter production, I would absolutely demand that it not be used on Earth until it had been used to send hundreds of human-bearing seed ships to other solar systems. The risk is too great.
Consider the energy and material engineering necessary to achieve long-distance space transport of any sizable amount of people, equipment, and supplies. Regardless of whether the transport is subluminal or FTL, the energy requirements are tremendous and the engineering requirements for a durable vessel astounding.
My guess is that by the time our materials science and our energy production are up to the task, our interests may well have changed - because (and here I speculate wildly) science at engineering at that level will reveal so much about the fundamental nature of the universe and give us so much interesting practical technology that biochemical life clinging desperately to lucky rocks in the lucky zone won't be near so interesting anymore.
No one comes near because we have nothing to offer those able to come near and get home again to report what they found.
As to simply detecting signals, we have to consider how lucky we are to have so much ore so close to the surface: Metallurgy and eventually radiated communications were a natural for us.
Other civilizations may well start with fantastically engineered wood and eventually plastics, and go all-fibre, all line-of-sight, and have very, very different communications systems, systems undetectable at any remove.
For the sake of argument let’s linger on that assumption for a while. How for example did they found us when our civilization achieved radio signals transmission in the last couple of centuries? That means that they’re close by, unless FTL travel is feasible in which case we can safely assume the whole galaxy should be teeming with life. But if they’re close by shouldn’t we be able to spot them? And if they’re far away that means they should already have colonized half the galaxy before they decide to launch an expedition to a planet thousands of light years away.
The worrying factor relating to the “Fermi Paradox” is that it suggests that maybe life is extremely rare. We could very well be the only living souls in this part of the Universe and that’s kind of heart breaking considering the sheer size of the whole thing.
By the way, your assumption is called the "Zoo Hypothesis" http://en.wikipedia.org/wiki/Zoo_hypothesis
Oh, and while we're in this scenario I'd urge everyone to read the following SF short. http://www.terrybisson.com/page6/page6.html
[1] http://www.amazon.com/Existence-David-Brin/dp/0765342626/ref=sr_1_3?ie=UTF8&qid=1428283635&sr=8-3&keywords=existence1 and 2 don't make sense if you assume that there are many alien civilizations older and more advanced than us. 3 implies that we're fundamentally misunderstanding a lot about (astro)physics.
Or the put it a bit different: unless the Culture want us to see it, we won't.
I mean there could easily be a couple 1000 years between us, which means that the difference is at least as great as us and the Romans. The Romans might very well question why we weren't breeding more horses then, since we have such a huge need of transport and horses are the best way to do that.
Is it? How do we know it is?
Loosing this rock or our star essentially equals the extinction of our species.
If this is why an intelligence can spread out on a planet, couldn't other intelligences (if they exist) spread out for similar reasons in the galaxy.
Barring several fairly large changes to our energy and resource systems, our civilization is mathematically and physically guaranteed to collapse within the next 200 years at most.
That's not a hypothetical filter. It's a real one that we can see, and we are not past it.
The Great Filter is just the thing that explains most of why intelligent life is (or seems) so rare in the universe. It could be true, for example, that some cosmic event kills life before it becomes technological 99% of the time (= Great Filter), and also that, say, 60% of technological civilizations destroy themselves via destroying their environment.
(1) An intelligence reaches a critical intellectual mass and begins to utilize the free resources that are present in its environment.
(2) In doing so it grows and develops exponentially.
(3) By the time it develops far enough intellectually to realize the problem -- exponential growth built on finite non-replenishable supply -- it's already too late.
We seem to have realized this problem around 1950-1970, and we have done very little about it so far. That's because huge complex systems are hard to change, and all the incentives point the wrong way.
Few nonrenewable resources have a remaining supply measured in hundreds of years.
> Barring several fairly large changes to our energy and resource systems, our civilization is mathematically and physically guaranteed to collapse within the next 200 years at most.
Would you mind elaborating on this or posting some links with more evidence for this? As stated, your claim seems reminiscent to previous claims that humanity would soon not be able to grow enough food for the projected population. So far, unexpected scientific advances have managed to increase food yields substantially, and we can now effectively produce more than enough food to feed people (though we clearly have issues ensuring that food gets to everyone who needs it). So I wonder what is different now, that makes this looming catastrophe "provable" and "mathematically and physically guaranteed".
I agree that humanity is facing significant challenges (e.g., climate change), but I think the claim of "guaranteed collapse" is not as well established.
This is a cautionary tale about something that stock market traders know well: never try to call the top of a bubble. You'll just look like a fool, and if you bet on it you will lose all your money.
The "Population Bomb" crowd in the 70s and the peak oilers of today tried to do just that: to call the top. They were not wrong about the underlying realities, but they were absolutely wrong about the timing -- which is nearly always the case. Bubbles almost always go higher and further than anyone ever expects or imagines.
We're exponentially growing on the back of finite resources that we are consuming without replenishing. That's a bubble. I don't know when it will pop, but it will. Question is what happens then, and will we have enough alternatives available to keep going or not?
On the counterpoint side:
Life faced a similar situation prior to the advent of photosynthesis. It was growing exponentially and consuming chemical resources that would have been depleted. Had photosynthesis not evolved in time, life would have likely mostly died out and retreated to small colonies around a few hydrothermal vents.
That might have been one of the first great filters. We seem to be past that one.
I'm not the GP, but I suspect api has in mind something like this [0]. The money quote from that article is this:
"At that 2.3% growth rate, we would be using energy at a rate corresponding to the total solar input striking Earth in a little over 400 years."
The obvious first-order thermodynamic consequences of that fact for the temperature of the surface of the earth are pretty undeniable.
[0] http://physics.ucsd.edu/do-the-math/2012/04/economist-meets-...
Though, to be a bit picky, showing that we can't indefinitely sustain our current trajectory is a different argument than saying a collapse is inevitable.
It's too early to say, but my money's on population crashing first. 100 years ago, you could see nearly anyplace a large population at something approaching the Malthusian limit; that's much reduced now.
The sore spots are worse but there are fewer of them. And something like a Haiti is extremely path dependent - it takes several improbable events conspiring to make one; so they can be unmade.
Jared Diamond's "Collapse" pretty much convinced me he was not just wrong but flat and 100% wrong. Through his writing , I learned to not only disapprove of apocolyptic narrative but how to counter it.
I would not be surprised of there were big, resource-oriented wars on the horizon but I doubt that'll lead to collapse, and I attribute those more to things like monetary policy and the odious politics of debt than human nature in the raw. It's difficult to explain just how violently wrong-headed people were in the 20th Century to create the big disasters.
I'm not talking about cleanliness. That's a quality of life factor but ultimately it's not what's important. The important thing is supply, mostly of energy.
(It's also important to note that to a great extent the West has cleaned up its environment by outsourcing polluting industries to Asia, Africa, and South America.)
Last I checked we still got more than 80% of our energy from fossil fuels. That has changed very, very little in the past 50 years. My grandparents drove a gasoline car, my parents drove a gasoline car, and I drive a gasoline car, and the power grid where I live is powered by 60% natural gas and 15% coal. Where I grew up it was almost 100% coal, same as it was three generations ago.
We were supposed to be driving EVs powered by fusion reactors by now.
If you're rich you can buy solar panels and an EV and convince yourself there is no problem, but until that stuff falls geometrically in price to the point that it achieves mass adoption it's a luxury toy that will make no impact. Either that or the future will require that 90% of humanity be reduced to medieval subsistence-level poverty. That's not quite the collapse some have predicted, but I highly doubt that sort of neo-feudal civilization is going to go to the stars. So it counts for the Fermi Paradox. The universe may be filled with such small, limited, planet-bound intelligences.
I'm slightly encouraged by an apparent Moore's Law in solar, but storage is now the bottleneck. I'm also very cynical about technological advancement outside of IT and a few other narrow areas. I agree with Peter Thiel that basically all major technological advancement outside of computers and some biotech stopped around 1970. Cars, planes, power plants, etc. are all basically the same today as they were then.
Cleanliness - basic control of waterborne disease, the level of schmutz from power, control of pernicious trash - is huge. Queen Victoria's husband Albert died of this sort of disease 150ish years ago. This is vanishingly rare now if it exists at all.
I don't buy "90% in medieval subsistence level poverty" because medieval subsistence level poverty doesn't scale. It went obsolete even with the potato as a base food crop in the early 19th Century - I'd accuse the Irish potato famine of ending anything remotely like it. If there's feudalism again, then it's because we can't organize ourselves in anything more efficient than that.
I can't say that some sort of Malthusian equilibrium is impossible, only that it seems unlikely. Historically, we had two notable examples in the 20th Century - the Ukrainian famine post the Bolshevik Revolution, and the Chinese Great Leap Forward. Both were, paradoxically, caused by belief systems grounded in Malthusian predictions. Now that's largely inductive predicting on my part, but we just know better now.
There's a heck of a lot of muddling through between going to the stars and a continuous Malthusian crisis. I'd say "going to the stars" has more than anything else failed to capture at least the popular imagination.