Hanson’s original great filter article is a great piece—especially for it’s time (given that the physical limits of compuation were less understood), but the entire terminology and framework leads to privileging the hypothesis that we are alone.
Part of the reason for that—I suspect—is that ever since the split between science and religion, science has strongly favored the natural explanation for any phenomena. If advanced aliens exist then it leads to some potentially unsettling implications.
People have also suggested that civilizations move outside galaxies to the cold of space where they can do efficient reversible computing using cold dark matter. Jacob Cannell has been one of the most vocal proponents of this idea.
Do you have other examples of this idea? I’m just curious where you may have encountered it.
Also—“outside the galaxies” is perhaps going to far. In more general form, the cold dark matter model just proposes that postbiological life will migrate away from stars, in contrast to the dyson-sphere stellavore model which proposes that advanced life stays near stars.
This hypothesis suffers from at least three problems. First, it fails to explain why those entities have not used the conventional matter to any substantial extent in addition to the cold dark matter.
Actually, the cold dark model does explain how advanced aliens use conventional matter—they turn it into reversible computronium arcilects, install shielding to cool the arcilect down, and then possibly eject the arcilect out into space. The ejection part is less certain and wouldn’t necessarily make sense for every planemo.
Unlike the stellavore model, the cold dark model actually matches our observations.
In general “Cold dark matter” includes any matter that is cold and does not emit significant radiation (dark), but my analysis was focused on conventional (baryonic) matter.
My key point is that reversible computing appears to be possible. If reversible computing is possible, no alien civilizations will build anything like dyson spheres, because those designs are incredibly inefficient compared to reversible computing based arcilects. Cold dark reversible arcilects are a vastly more computationally powerful use of the same mass resources. There is no need to dissamble the system and collect all the solar energy because you barely need solar energy at all.
Second, this hypothesis would either require dark matter composed of cold conventional matter (which at this point seems to be only a small fraction of all dark matter), or would require dark matter which interacts with itself using some force other than gravity.
No—the hypothesis is not somehow required to ‘explain dark matter’, even though that would be nice (does the dyson sphere hypothesis explain dark matter?), and the hypothesis works either way. If it is possible to build advanced computing arcilects out of unconventional matter, then we should indeed expect aliens to colonize/use the unconventional matter, but that would presumably come only after first colonizing the conventional matter. If computers can only be built of conventional baryonic matter, then they only use that. Either way the baryonic matter gets used first and it doesnt change much.
Third, even if some species had taken over a large fraction of dark matter to use for their own computations, one would then expect later species to use the conventional matter since they would not have the option of using the now monopolized dark matter.
Again my model primarily focuses on conventional (baryonic) matter. You seem to be confusing the baryonic/non-baryonic issue with the temperature/emission issue.
In my cold dark matter model, aliens start on warm planets, they transition to posbiological AI, then they colonize their system, turning many of the solid bodies (and perhaps to some limited extent the gas giants) into advanced reversible computing arcilects, which they cool as much as they can in place using reflective shielding/high albedo, etc. Then they possibly begin to eject some of the arcilects from the system, using complex gravitational assists.
From a distance, these changes are not hugely obvious, but there are some ways to potentially observe changes to albedo. And we could model ejections—if artificial ejections do occur then we may already being seeing the results. As another example, perhaps jovian planets migrating close into the sun is not a natural phenomenon. And so on.
We now know that there is more stuff (planemos) outside of stellar systems—nomads—then attached, which is supportive. Nomads which formed or ejected naturally are also colonized over time.
People have also suggested that civilizations move outside galaxies to the cold of space where they can do efficient reversible computing using cold dark matter. Jacob Cannell has been one of the most vocal proponents of this idea.
Do you have other examples of this idea? I’m just curious where you may have encountered it.
Hanson mentions it in the original Great Filter piece, and I’ve seen it discussed elsewhere on the internet in internet fora (for example, r/futurology on Reddit).
You’re correct that I should do a better job distinguishing the various versions of this hypothesis. I do think they run into essentially the same problems; reversible computing doesn’t mean one has unlimited computational power. If the material in question is conventional baryonic matter then it cannot be a large fraction of actual dark matter, so it loses the appeal of being an explanation for that (and yes, the other explanations for the Filter don’t explain dark matter, but versions of this at one point had this as their main selling point). Moreover, it isn’t at all clear how you would have multiple such objects communicate with each other.
A few months ago, I asked you here what you thought the form of these dark matter entities were and you didn’t reply. It seems that since then you’ve thought a lot more about this. I’m going to have to think carefully about what you have said above and get back to you later.
Hanson mentions it in the original Great Filter piece, and I’ve seen it discussed elsewhere on the internet in internet fora (for example, r/futurology on Reddit).
It’s true he discusses dark matter. He doesn’t mention reversible computing or the Landauer limit though, although to be fair when he wrote that article reversible computing was relatively unknown.
I’m now realizing that my use of the term ‘dark matter’ is unfortunate because it typically means an exotic form of matter, whereas I am talking about dark regular baryonic matter.
If the material in question is conventional baryonic matter then it cannot be a large fraction of actual dark matter, so it loses the appeal of being an explanation for that (and yes, the other explanations for the Filter don’t explain dark matter, but versions of this at one point had this as their main selling point).
The dark energy/matter problem in cosmology is still very mysterious. The current main solutions call for new forms of exotic matter/energy, and many of the detection experiments have generated null/wierd results. There’s alot going there in cosmology and it will take a while to sort out.
Also, there was some new research just recently showing that type Ia supernovae are more diverse than originally thought, which is causing a rethink of the rate of expansion, and thus the whole dark energy issue—as the supernova measurements were used as distance beacons.
Now regardless of what is going on with dark energy and non-baryonic dark matter. the issue of dark vs light baryonic matter is separate, and the recent evidence indicates a favorable high ratio of extrasolar dark baryonic planemos in the form of nomads.
The actual mass ratios for dark vs light baryonic matter are also unimportant for this model in the sense that what really matters is the fraction of metallic mass—most of the matter is hydrogen/helium and such that is probably not as useful for computation.
Moreover, it isn’t at all clear how you would have multiple such objects communicate with each other.
? The planck satellite maintained a 0.1K temperature for some key components and we had no issues communicating with it. External communication with a reversible computer doesn’t even require energy expenditure in theory, but it probably does in practice, but the expenditures for communication can be tiny—especially given enormous computational resources for compression.
A few months ago, I asked you here what you thought the form of these dark matter entities were and you didn’t reply. It seems that since then you’ve thought a lot more about this.
I have written about this before (on my blog) - I didn’t reply back then because I was busy and didn’t have much time for LW or thinking about aliens ;)
Hanson’s original great filter article is a great piece—especially for it’s time (given that the physical limits of compuation were less understood), but the entire terminology and framework leads to privileging the hypothesis that we are alone.
Part of the reason for that—I suspect—is that ever since the split between science and religion, science has strongly favored the natural explanation for any phenomena. If advanced aliens exist then it leads to some potentially unsettling implications.
Do you have other examples of this idea? I’m just curious where you may have encountered it.
Also—“outside the galaxies” is perhaps going to far. In more general form, the cold dark matter model just proposes that postbiological life will migrate away from stars, in contrast to the dyson-sphere stellavore model which proposes that advanced life stays near stars.
Actually, the cold dark model does explain how advanced aliens use conventional matter—they turn it into reversible computronium arcilects, install shielding to cool the arcilect down, and then possibly eject the arcilect out into space. The ejection part is less certain and wouldn’t necessarily make sense for every planemo.
Unlike the stellavore model, the cold dark model actually matches our observations.
In general “Cold dark matter” includes any matter that is cold and does not emit significant radiation (dark), but my analysis was focused on conventional (baryonic) matter.
My key point is that reversible computing appears to be possible. If reversible computing is possible, no alien civilizations will build anything like dyson spheres, because those designs are incredibly inefficient compared to reversible computing based arcilects. Cold dark reversible arcilects are a vastly more computationally powerful use of the same mass resources. There is no need to dissamble the system and collect all the solar energy because you barely need solar energy at all.
No—the hypothesis is not somehow required to ‘explain dark matter’, even though that would be nice (does the dyson sphere hypothesis explain dark matter?), and the hypothesis works either way. If it is possible to build advanced computing arcilects out of unconventional matter, then we should indeed expect aliens to colonize/use the unconventional matter, but that would presumably come only after first colonizing the conventional matter. If computers can only be built of conventional baryonic matter, then they only use that. Either way the baryonic matter gets used first and it doesnt change much.
Again my model primarily focuses on conventional (baryonic) matter. You seem to be confusing the baryonic/non-baryonic issue with the temperature/emission issue.
In my cold dark matter model, aliens start on warm planets, they transition to posbiological AI, then they colonize their system, turning many of the solid bodies (and perhaps to some limited extent the gas giants) into advanced reversible computing arcilects, which they cool as much as they can in place using reflective shielding/high albedo, etc. Then they possibly begin to eject some of the arcilects from the system, using complex gravitational assists.
From a distance, these changes are not hugely obvious, but there are some ways to potentially observe changes to albedo. And we could model ejections—if artificial ejections do occur then we may already being seeing the results. As another example, perhaps jovian planets migrating close into the sun is not a natural phenomenon. And so on.
We now know that there is more stuff (planemos) outside of stellar systems—nomads—then attached, which is supportive. Nomads which formed or ejected naturally are also colonized over time.
Hanson mentions it in the original Great Filter piece, and I’ve seen it discussed elsewhere on the internet in internet fora (for example, r/futurology on Reddit).
You’re correct that I should do a better job distinguishing the various versions of this hypothesis. I do think they run into essentially the same problems; reversible computing doesn’t mean one has unlimited computational power. If the material in question is conventional baryonic matter then it cannot be a large fraction of actual dark matter, so it loses the appeal of being an explanation for that (and yes, the other explanations for the Filter don’t explain dark matter, but versions of this at one point had this as their main selling point). Moreover, it isn’t at all clear how you would have multiple such objects communicate with each other.
A few months ago, I asked you here what you thought the form of these dark matter entities were and you didn’t reply. It seems that since then you’ve thought a lot more about this. I’m going to have to think carefully about what you have said above and get back to you later.
It’s true he discusses dark matter. He doesn’t mention reversible computing or the Landauer limit though, although to be fair when he wrote that article reversible computing was relatively unknown.
I’m now realizing that my use of the term ‘dark matter’ is unfortunate because it typically means an exotic form of matter, whereas I am talking about dark regular baryonic matter.
The dark energy/matter problem in cosmology is still very mysterious. The current main solutions call for new forms of exotic matter/energy, and many of the detection experiments have generated null/wierd results. There’s alot going there in cosmology and it will take a while to sort out.
Also, there was some new research just recently showing that type Ia supernovae are more diverse than originally thought, which is causing a rethink of the rate of expansion, and thus the whole dark energy issue—as the supernova measurements were used as distance beacons.
Now regardless of what is going on with dark energy and non-baryonic dark matter. the issue of dark vs light baryonic matter is separate, and the recent evidence indicates a favorable high ratio of extrasolar dark baryonic planemos in the form of nomads.
The actual mass ratios for dark vs light baryonic matter are also unimportant for this model in the sense that what really matters is the fraction of metallic mass—most of the matter is hydrogen/helium and such that is probably not as useful for computation.
? The planck satellite maintained a 0.1K temperature for some key components and we had no issues communicating with it. External communication with a reversible computer doesn’t even require energy expenditure in theory, but it probably does in practice, but the expenditures for communication can be tiny—especially given enormous computational resources for compression.
I have written about this before (on my blog) - I didn’t reply back then because I was busy and didn’t have much time for LW or thinking about aliens ;)