What if post-singularity civilizations expand at the speed of light? Then we should not expect to see anything:
It looks like we are going to have less than 200 years between interstellar detectability and singularity. So the chance of us being around at the same time (adjusted for distance) as another civilization to a resolution of a few hundred years seems quite low.
Life will only get to the point of asking questions like these on worlds that haven’t been ground up for resources, so we can only be outside the “expansion cone” of any post-singularity civilization. If the expansion cone and the light cone are close (within a few hundred years), then, given that we are outside of the expansion cone, we are probably outside the light cone as well. So the AI-as filter doesn’t get falsified by observing no AIs.
It doesn’t even have to be a filter, though it probably is; 100% of civilizaions could successfully navigate the intelligence explosion and we would see nothing, because we can only exist in the last corner of the universe that hasn’t been ground up by them.
This is all assuming lightspeed expansion. Here’s a few ideas: a single nanoseed catapulted at 99.9 % the speed of light, followed by a laser encoding the instructions. Cross galaxy light-lag would be only 100 years. How to slow it down on arrival is unknown… Another possibility is actually creating spaceships out of light; some kind of super laser that would excite whatever it hit in just the right way to create a nanoseed. This one seems mush less plausible, but I wouldn’t bet against the engineering skill of a superintelligence.
What if post-singularity civilizations expand at the speed of light? Then we should not expect to see anything. [...]
Then it spreads throughout the galaxy in 100,000 light years. The Fermi paradox is not really affected—there are still no alien superintelligent machines visible here.
Why is it not affected? If we assume they expand at a negligible fraction of the speed of light, we expect them to be visible from the outside for their entire lifetime (which may be very long). On the other hand if we expect them to expand at nearly the speed of light, we expect them to be detectable from outside for only a few hundred years.
The other side of the galaxy could very well be already consumed by an alien civilization.
If intelligent life was common and underwent such expansion, then there would be very few new-arising lonely civilizations later in the history of the universe (the real estate for their evolution already occupied or filled with signs of intelligence). The overwhelming majority of civilizations evolving with empty skies would be much younger.
So, whether you attend to the number of observers with our observations, or the proportion of all observers with such observations, near-c expansion doesn’t help resolve the Fermi paradox.
Another way of thinking about it is: we are a civilization that has developed without seeing any sign of aliens, developed on a planet that had not been colonized by aliens. Colonization would have prevented our observations just as surely as alien transmissions or a visibly approaching wave of colonization.
Assume life is rare/filtered, we straightforwardly expect to see what we see (empty sky).
Assume life is common and the singularity comes quickly and reliably, and colonization proceeds at the speed of light, then condition on the fact that we are pre-singularity. As far as I can tell, a random young civilization still expects empty skies, possibly slightly less because of the relatively small volume of spacetime where we would observe an approaching colonization wave.
So the observation of empty skies is only very weak evidence against life being common, given that this singularity stuff is sound.
The latter hypothesis is more specific, but I already believe all those assumptions (quick, reliable, and near-c).
Given that I take those singularity assumptions seriously (not just hypothetically), and given that we are where we are in the history of the universe, the fermi paradox seems resolved for me; I find it unlikely that a given young civilization would observe any other civilization, no matter the actual rate of life. If we did observe another isolated civilization it would be pretty much falsify my “quick,reliable, and lightspeed” singularity belief.
However, as you say, that “given that we are where we are in the history of the universe” is worrying. I predict most young civilizations to be early (because the universe gets burned up quickly), and I predict most civilizations to not be young, given that life is common. When we observe ourselves to be young and late (are we actually late?), fermi’s paradox results. I guess in this case fermi’s paradox is that we observed something that is a priori unlikely, and we wonder what unlikely alternate hypotheses this digs up (the above, for one). However, anthropics is very confusing...
I predict most young civilizations to be early (because the universe gets burned up quickly), and I predict most civilizations to not be young, given that life is common. When we observe ourselves to be young and late (are we actually late?), Fermi’s paradox results.
Here’s a few ideas: a single nanoseed catapulted at 99.9 % the speed of light, followed by a laser encoding the instructions. Cross galaxy light-lag would be only 100 years. How to slow it down on arrival is unknown… Another possibility is actually creating spaceships out of light; some kind of super laser that would excite whatever it hit in just the right way to create a nanoseed.
As envisioned in Olaf Stapledon’s classic Last and First Men, [free here]:
(Read, then guess the year of publication!)
In respect of the future, we are now setting about the forlorn task of disseminating among the stars the seeds of a new humanity. For this purpose we shall make use of the pressure of radiation from the sun, and chiefly the extravagantly potent radiation that will later be available. We are hoping to devise extremely minute electro-magnetic “wave-systems,” akin to normal protons and electrons, which will be individually capable of sailing forward upon the hurricane of solar radiation at a speed not wholly incomparable with the speed of light itself. This is a difficult task. But, further, these units must be so cunningly inter-related that, in favourable conditions, they may tend to combine to form spores of life, and to develop, not indeed into human beings, but into lowly organisms with a definite evolutionary bias toward the essentials of human nature. These objects we shall project from beyond our atmosphere in immense quantities at certain points of our planet’s orbit, so that solar radiation may carry them toward the most promising regions of the galaxy. The chance that any of them will survive to reach their destination is small, and still smaller the chance that any of them will find a suitable environment. But if any of this human seed should fall upon good ground, it will embark, we hope, upon a somewhat rapid biological evolution, and produce in due season whatever complex organic forms are possible in its environment. It will have a very real physiological bias toward the evolution of intelligence. Indeed it will have a much greater bias in that direction than occurred on the Earth in those sub-vital atomic groupings from which terrestrial life eventually sprang.
I am not a physicist, so I didn’t and couldn’t do the calculations, but I don’t really believe that classic probes can reach .999c. They would be pulverised by intergalactic material. Even worse, literal .999c would not be fast enough for this fancy “hits us before we know it” filter idea to work. As I explained in some of the above-quoted threads, my bet would definitely be on the things you called “spaceships out of light”. A sufficiently advanced civilisation might switch from atoms to photons as their substrate. The only resource they would extract from the volume of space they consume would be negentropy, so they wouldn’t need any slowing down or seeds. Again, I am not a physicist. I discussed this with some physicists, and they were sceptic, but their objections seemed to be of the engineering kind, not theoretic kind, and I’m not sure they sufficiently internalized “don’t bet against the engineering skill of a superintelligence”.
For me, one source of inspiration for this light-speed expansion idea was Stanislav Lem’s “His Master’s Voice”, where precisely tuned radio waves are used to catalyse the formation of DNA-based life on distant planets. (Obviously that’s way too slow for the purposes we discuss here.)
Photons can’t interact with each other (by the linearity of Maxwell’s equations) and so can’t form a computational substrate on their own. This doesn’t rule out “no atoms” computing in general though.
EDIT: I’m wrong. When you do the calculations in full quantum field theory there is a (extremely) slight interaction (due to creations and destructions of electron-postitron pairs, which in some sense destroy the linearity). I don’t know if this is enough to support computers.
They would be pulverised by intergalactic material.
That’s actually concerning. Maybe it isn’t possible to shoot matter intact across the galaxy… Would have to do the calculations with interstellar particle density.
Also, surely you mean “interstellar”? I was only thinking of interstellar travel for now; assuming intergalactic is impossible or whatever.
Even worse, literal .999c would not be fast enough for this fancy “hits us before we know it” filter idea to work.
Not for intergalactic, but the galaxy is 100k lightyears across. 0.999c would get you a lag behind the light of 100 years, which is on the same order of magnitude as the time between detectability and singularity (looks like < 200 years for us).
A sufficiently advanced civilisation might switch from atoms to photons as their substrate. The only resource they would extract from the volume of space they consume would be negentropy, so they wouldn’t need any slowing down or seeds.
How would one eat a star without slowing down, even in principle?
precisely tuned radio waves are used to catalyse the formation of DNA-based life on distant planets. (Obviously that’s way too slow for the purposes we discuss here.)
This is closer to what I was thinking, but of course if you can catalyze DNA, you can catalyze arbitrary nanomachines. Exactly how this would work is a mystery to me… (also, doing it with radio waves is needlessly difficult, surely you’d use something precise and ionizing like UV, Xrays, or gamma)
Also, surely you mean “interstellar”? I was only thinking of interstellar travel for now; assuming intergalactic is impossible or whatever.
When you look at it from a Fermi paradox perspective, you have to be able to account for many hundred million years of expansion, because there can be many civilizations that are that much older than us. We are talking about some crazy thing that is supposed to be able to consume a galaxy with almost-optimal speed. I don’t expect galaxy boundaries to stop it completely, neither by intention nor by necessity. I am not even sure that it has to treat intergalactic space as the long boring travel between the rare interesting parts. Maybe all it really needs is empty space.
0.999c would get you a lag behind the light of 100 years, which is on the same order of magnitude as the time between detectability and singularity (looks like < 200 years for us).
Interesting point.
How would one eat a star without slowing down, even in principle?
Note that I speculated about photons as a substrate. Maybe major reorganization of atoms in unnecessary, and it can just fill the space around the star, and utilize the star as a photon source.
Fire a particle accelerator that can fire a smaller von neuman probe at -.999c. The particle accelerator could be built and assembled during the trip if it’s too unwieldy to fire directly.
What if post-singularity civilizations expand at the speed of light?
This is sort of valid but it is extremely unlikely. Even if expansion occurs at say .99% of light then the problem will still exist. One needs to be expanding extremely close (implausibly close?) to the speed of light for this explanation to work.
We have particle accelerators that achieve Lorentz factors of 7,500. I proposed a Lorentz factor of 22. Never mind a superintelligence, we, are on the brink of being able to accelerate nanomachines to that speed (assuming we had nanomachines).
The only implausible thing is being able to decelerate non-destructively at the target, and none of us have given that even 5 whole minutes of serious thought, never mind a couple trillion superintelligent FLOPS.
Nanobot is hard to de-accelerate, but a robust femtobot might do better.
Hmm, using the femtobot, would it being charged and entering a conductive material slow it down due to that induction thingy, like a magnet dropped down a copper tube? Or maybe having a conductive right shaped bot, and launching it into a ludicrously strong magnetic field of a neutron star or something.?
Another option is to launch a black hole in front of it, and give both the probe and black hole extremely strong negative charge; the black hole will absorb impacting matter (also solving the problem of interstellar dust) slowing it down by averaging, simultaneously clearing a safe path for the probe and gently pushing it back as it gets closer and the charges repel.
The black hole idea is interesting. Does it even have to be a black hole?
Any big non-functional absorbent mass at the front would do, right? Maybe only a black hole would be reliable...
Maybe not even a mass. If the probe had a magnetic field, you might be able to do things with the bussard ramjet idea to slow you down and control (charged) collisions.
Here are my five minutes: nanomachines need to carry a charge to be accelerable, right? Well, it works the other way too—they will decelerate on their own in destination’s Van Allen belts.
They don’t actually decelerate in the Van Allen belts, though. Magnetic fields apply a force to a charged particle perpendicular to it’s direction of motion. F*V = Deceleration Power = 0. Also worth noting that a charged nanomachine has a much higher mass/charge ratio than the usual charged particles (He2+, H+, and e-), so it would be much less affected.
I was actually thinking of neutralizing the seed at the muzzle to avoid troublesome charge effects.
What if post-singularity civilizations expand at the speed of light? Then we should not expect to see anything:
It looks like we are going to have less than 200 years between interstellar detectability and singularity. So the chance of us being around at the same time (adjusted for distance) as another civilization to a resolution of a few hundred years seems quite low.
Life will only get to the point of asking questions like these on worlds that haven’t been ground up for resources, so we can only be outside the “expansion cone” of any post-singularity civilization. If the expansion cone and the light cone are close (within a few hundred years), then, given that we are outside of the expansion cone, we are probably outside the light cone as well. So the AI-as filter doesn’t get falsified by observing no AIs.
It doesn’t even have to be a filter, though it probably is; 100% of civilizaions could successfully navigate the intelligence explosion and we would see nothing, because we can only exist in the last corner of the universe that hasn’t been ground up by them.
This is all assuming lightspeed expansion. Here’s a few ideas: a single nanoseed catapulted at 99.9 % the speed of light, followed by a laser encoding the instructions. Cross galaxy light-lag would be only 100 years. How to slow it down on arrival is unknown… Another possibility is actually creating spaceships out of light; some kind of super laser that would excite whatever it hit in just the right way to create a nanoseed. This one seems mush less plausible, but I wouldn’t bet against the engineering skill of a superintelligence.
Then it spreads throughout the galaxy in 100,000 light years. The Fermi paradox is not really affected—there are still no alien superintelligent machines visible here.
Why is it not affected? If we assume they expand at a negligible fraction of the speed of light, we expect them to be visible from the outside for their entire lifetime (which may be very long). On the other hand if we expect them to expand at nearly the speed of light, we expect them to be detectable from outside for only a few hundred years.
The other side of the galaxy could very well be already consumed by an alien civilization.
E.g. check with http://en.wikipedia.org/wiki/Fermi_paradox
The rate of expansion makes very little difference, and a high rate of expansion is not listed as a possible resolution.
That article has little about the effect of expansion. Why does it not affect it? What is wrong with my argument that it should matter?
A near-c rate of expansion drastically reduces the volume of space that a given civilization is observable from. What specifically is wrong with this?
If intelligent life was common and underwent such expansion, then there would be very few new-arising lonely civilizations later in the history of the universe (the real estate for their evolution already occupied or filled with signs of intelligence). The overwhelming majority of civilizations evolving with empty skies would be much younger.
So, whether you attend to the number of observers with our observations, or the proportion of all observers with such observations, near-c expansion doesn’t help resolve the Fermi paradox.
Another way of thinking about it is: we are a civilization that has developed without seeing any sign of aliens, developed on a planet that had not been colonized by aliens. Colonization would have prevented our observations just as surely as alien transmissions or a visibly approaching wave of colonization.
I still don’t get it.
Assume life is rare/filtered, we straightforwardly expect to see what we see (empty sky).
Assume life is common and the singularity comes quickly and reliably, and colonization proceeds at the speed of light, then condition on the fact that we are pre-singularity. As far as I can tell, a random young civilization still expects empty skies, possibly slightly less because of the relatively small volume of spacetime where we would observe an approaching colonization wave.
So the observation of empty skies is only very weak evidence against life being common, given that this singularity stuff is sound.
The latter hypothesis is more specific, but I already believe all those assumptions (quick, reliable, and near-c).
Given that I take those singularity assumptions seriously (not just hypothetically), and given that we are where we are in the history of the universe, the fermi paradox seems resolved for me; I find it unlikely that a given young civilization would observe any other civilization, no matter the actual rate of life. If we did observe another isolated civilization it would be pretty much falsify my “quick,reliable, and lightspeed” singularity belief.
However, as you say, that “given that we are where we are in the history of the universe” is worrying. I predict most young civilizations to be early (because the universe gets burned up quickly), and I predict most civilizations to not be young, given that life is common. When we observe ourselves to be young and late (are we actually late?), fermi’s paradox results. I guess in this case fermi’s paradox is that we observed something that is a priori unlikely, and we wonder what unlikely alternate hypotheses this digs up (the above, for one). However, anthropics is very confusing...
Fermi’s paradox also makes mention of the fact that there are billions of stars in the galaxy that are billions of years older than ours, many of them having habitable planets. Some reasons have prevented any of these from spawning a galactic colonization wave—and those reasons are of interest to us.
Yes and yes.
As envisioned in Olaf Stapledon’s classic Last and First Men, [free here]:
(Read, then guess the year of publication!)
Year of publication? Rot13: avargrra guvegl!
Here are a couple of scattered short LW comments where I discussed this possibility and considered counterarguments and implementations.
Interesting. You seem to have exactly the same thoughts as me.
How do you think one might slow down a .999*c von neuman probe at the destination?
I am not a physicist, so I didn’t and couldn’t do the calculations, but I don’t really believe that classic probes can reach .999c. They would be pulverised by intergalactic material. Even worse, literal .999c would not be fast enough for this fancy “hits us before we know it” filter idea to work. As I explained in some of the above-quoted threads, my bet would definitely be on the things you called “spaceships out of light”. A sufficiently advanced civilisation might switch from atoms to photons as their substrate. The only resource they would extract from the volume of space they consume would be negentropy, so they wouldn’t need any slowing down or seeds. Again, I am not a physicist. I discussed this with some physicists, and they were sceptic, but their objections seemed to be of the engineering kind, not theoretic kind, and I’m not sure they sufficiently internalized “don’t bet against the engineering skill of a superintelligence”.
For me, one source of inspiration for this light-speed expansion idea was Stanislav Lem’s “His Master’s Voice”, where precisely tuned radio waves are used to catalyse the formation of DNA-based life on distant planets. (Obviously that’s way too slow for the purposes we discuss here.)
Photons can’t interact with each other (by the linearity of Maxwell’s equations) and so can’t form a computational substrate on their own. This doesn’t rule out “no atoms” computing in general though.
EDIT: I’m wrong. When you do the calculations in full quantum field theory there is a (extremely) slight interaction (due to creations and destructions of electron-postitron pairs, which in some sense destroy the linearity). I don’t know if this is enough to support computers.
That’s actually concerning. Maybe it isn’t possible to shoot matter intact across the galaxy… Would have to do the calculations with interstellar particle density.
Also, surely you mean “interstellar”? I was only thinking of interstellar travel for now; assuming intergalactic is impossible or whatever.
Not for intergalactic, but the galaxy is 100k lightyears across. 0.999c would get you a lag behind the light of 100 years, which is on the same order of magnitude as the time between detectability and singularity (looks like < 200 years for us).
How would one eat a star without slowing down, even in principle?
This is closer to what I was thinking, but of course if you can catalyze DNA, you can catalyze arbitrary nanomachines. Exactly how this would work is a mystery to me… (also, doing it with radio waves is needlessly difficult, surely you’d use something precise and ionizing like UV, Xrays, or gamma)
When you look at it from a Fermi paradox perspective, you have to be able to account for many hundred million years of expansion, because there can be many civilizations that are that much older than us. We are talking about some crazy thing that is supposed to be able to consume a galaxy with almost-optimal speed. I don’t expect galaxy boundaries to stop it completely, neither by intention nor by necessity. I am not even sure that it has to treat intergalactic space as the long boring travel between the rare interesting parts. Maybe all it really needs is empty space.
Interesting point.
Note that I speculated about photons as a substrate. Maybe major reorganization of atoms in unnecessary, and it can just fill the space around the star, and utilize the star as a photon source.
Fire a particle accelerator that can fire a smaller von neuman probe at -.999c. The particle accelerator could be built and assembled during the trip if it’s too unwieldy to fire directly.
An implicit assumption here is that alien civilizations have an observation weight of zero.
If complex space-faring civilizations have spread across the galaxy to produce lots of observers capable of anthropic reasoning, why aren’t we in one?
If they don’t, doesn’t that just reframe the Filter? Technological evolution into Blindsight-style Scramblers sure sounds like extinction to me.
This is sort of valid but it is extremely unlikely. Even if expansion occurs at say .99% of light then the problem will still exist. One needs to be expanding extremely close (implausibly close?) to the speed of light for this explanation to work.
We have particle accelerators that achieve Lorentz factors of 7,500. I proposed a Lorentz factor of 22. Never mind a superintelligence, we, are on the brink of being able to accelerate nanomachines to that speed (assuming we had nanomachines).
The only implausible thing is being able to decelerate non-destructively at the target, and none of us have given that even 5 whole minutes of serious thought, never mind a couple trillion superintelligent FLOPS.
Nanobot is hard to de-accelerate, but a robust femtobot might do better.
Hmm, using the femtobot, would it being charged and entering a conductive material slow it down due to that induction thingy, like a magnet dropped down a copper tube? Or maybe having a conductive right shaped bot, and launching it into a ludicrously strong magnetic field of a neutron star or something.?
Another option is to launch a black hole in front of it, and give both the probe and black hole extremely strong negative charge; the black hole will absorb impacting matter (also solving the problem of interstellar dust) slowing it down by averaging, simultaneously clearing a safe path for the probe and gently pushing it back as it gets closer and the charges repel.
Femto? Explain.
The black hole idea is interesting. Does it even have to be a black hole? Any big non-functional absorbent mass at the front would do, right? Maybe only a black hole would be reliable...
Maybe not even a mass. If the probe had a magnetic field, you might be able to do things with the bussard ramjet idea to slow you down and control (charged) collisions.
not very good but good enough: http://en.wikipedia.org/wiki/Femtotech
ANd I were just brainstorming, your guess is as good as mine. But yea a tiny neutron star might work.
Here are my five minutes: nanomachines need to carry a charge to be accelerable, right? Well, it works the other way too—they will decelerate on their own in destination’s Van Allen belts.
They don’t actually decelerate in the Van Allen belts, though. Magnetic fields apply a force to a charged particle perpendicular to it’s direction of motion. F*V = Deceleration Power = 0. Also worth noting that a charged nanomachine has a much higher mass/charge ratio than the usual charged particles (He2+, H+, and e-), so it would be much less affected.
I was actually thinking of neutralizing the seed at the muzzle to avoid troublesome charge effects.