8 ms·

Interesting points, though the abstract is quite hard to follow. I guess it makes sense: 1. aliens spread at a certain speed after developing spaceflight

Interesting points, though the abstract is quite hard to follow. I guess it makes sense: 1. aliens spread at a certain speed after developing spaceflight 2. they're not here 3. there are no spacefaring aliens in the galaxy currently

AutumnCurtain 5y ago
I felt like I could have used a better articulation of their definition of "loud" and "quiet" aliens, unless these are well known terms in the domain terms and I am just unfamiliar...
- mannykannot 5y ago
  The abstracts of papers are intentionally terse, which usually means they are addressed to people already familiar with the field. The paper itself is often more readable (though by no means always!) and it is often worth taking a look at the introduction and conclusion, at least. Here, we have 'To a first approximation, there are two kinds of aliens: quiet and loud. Loud (or “expansive”) aliens expand fast, last long, and make visible changes to their volumes. Quiet aliens fail to meet at least one of these criteria.'
- deleted 5y ago
  [deleted]
7thaccount 5y ago
The Fermi Paradox (where is everyone) has been debated for decades. There are so many possibilities such as great filters (early or late), prime directive, zoo hypothesis, dark forest hypothesis...etc etc. I'm sure you're aware of this, but I included just in case you wanted to explore in more depth. Some really good stuff.
- AtlasBarfed 5y ago
  I just heard about the dark forest a couple weeks ago. I believe it to be the model we should proceed with for safety. Assuming FTL isn't possible, the fact that dark energy makes large sections of the visible universe fundamentally inaccessible is probably a good thing. Otherwise that is a lot more of the universe that may be ahead of us and would stomp us like ants.
  - betwixthewires 5y ago
    Unless something about life is fundamentally adversarial I wouldn't expect civilizations to be hostile to one another by default. You could make the argument that it does appear that life is fundamentally adversarial, seeing as in our one example all life feeds on other life, and to sustain life a creature must kill. I believe that's simple a circumstance of limited biomass in a closed system and so not fundamental, but you could argue that all civilizations probably get bootstrapped in this way and so it doesn't need to be fundamentally adversarial, but that all civilizations are accustomed to it so the distinction "fundamental" does not really matter. I'd disagree with that also, because a change in conditions to post scarcity changes conditioning and therefore behavior. You might also come up with a prisoners dilemma type scenario where a civilization doesn't want to be adversarial, but it doesn't know the intentions of others and so to protect itself, as a rule, destroys any that it finds. This is somewhat plausible but I don't really think likely because civilizations that evolved from abiogenetic origins separate from one another would likely have very very different behaviors that might not even overlap in many cases, so even if they were aware of each other they may not even be capable of interacting. It just does not make sense for a space faring civilization to be hostile. A requirement for space faring and a result of it is post scarcity; resources abound in the vast swathes of dead universe. There is no reason to even think competitively, barring some as yet undiscovered unobtanium so rare and so powerful that civilizations fight to extinction over it, but I doubt it. If anything, I'd think that a space faring civilization benefits the more it understands the universe, and learning about biospheres and civilizations with completely different evolutionary paths from abiogenesis would be more valuable than destruction of them.
Retric 5y ago
#1 has some huge assumptions built in. A civilization can travel a long distance without visiting every star system between it’s origin and destination. The limitation could be doubling time not travel time. Sure double every 100,000 years or less and in 4 million years you’ve run out of stars in the Milky Way which is an eye blink on cosmic timescales. But, a civilization that’s remote terraforming worlds that might greatly slow things down. How long does it take Cyanobacteria to create an oxygen atmosphere for example?
addingnumbers 5y ago
A turtle on the Galápagos Islands in 1450AD could use the same reasoning to conclude that no seafaring civilizations existed.
- hansbo 5y ago
  Yeah, but if humans keep existing for millions of years, then the probability for a turtle on the Galápagos Islands to live in the time between when humans started seafaring and when humans visited the islands would be extremely small compared to any other time period.
  - addingnumbers 5y ago
    Since we know the conclusion to be false, any reasoning that would support this hypothetical turtle's conclusion that no seafarers existed in 1450 is inarguably an example of bad reasoning.
    - gpm 5y ago
      No, because the turtle is concluding that it's likely false, not definitely false. There happens to be a cosmic coincidence working against the turtle, but that doesn't mean that it was bad reasoning to conclude that the cosmic coincidence was very unlikely.
      - addingnumbers 5y ago
        The turtle is saying with certainty, not likelihood, that no seafarers exist, analogous with the explicit conclusion (3) in the top level comment
        gpm 5y ago
        People are lazy when they speak, it's best to understand basically every claim as probabilistic (and meaning "almost certainly") even when it isn't stated as such. Certainly no-one would make the claim that "there are (definitely) no aliens in the galaxy" when we can't disprove the idea that aliens traveling at the speed of light just reached the galaxy (with our current understanding of physics). That doesn't mean you can't make the claim "there are (almost definitely) no aliens in the galaxy (because I just created the most amazing telescope ever and looked at every particle of matter in the galaxy and there were no aliens there)". The principle of charity demands that understand the bare claim that "there are no aliens in the galaxy" to mean something that is plausible, such as "there are almost certainly no aliens in the galaxy".
m3kw9 5y ago
The incentives and disincentives of exploring other systems is largely unknown. There could be huge risks in visiting other systems in which your own system of origin could be revealed if you happen to find another advanced civilization, I would think if a civilization is even predicted to be in a system, it will likely not be visited.
jamesdmiller 5y ago
Hanson doesn't think (2) and (3) follow because of the possibility of panspermia. It's possible that our galaxy is the only one in a billion light years that has given rise to life, but there could, because of panspermia, skill be a high probability that a planet in our galaxy outside our solar system has life. See this podcast Hanson did with me: https://soundcloud.com/user-519115521 https://soundcloud.com/user-519115521
- blfr 5y ago
  Your podcasts with Greg Cochran are quite possibly the most interesting (interesting stuff per minute) audio I've ever listened to.
  - jamesdmiller 5y ago
    Thanks!
rsynnott 5y ago
I think (1) is probably the main questionable assumption, to be honest. Let's take as given that travel faster than light via some form of cheating isn't possible. Under that assumption, for mass interstellar travel in reasonable time, you would require the ability to produce vast amounts of cheap energy (either via fusion on the starship, or antimatter produced with cheap energy at home and used on the starship, or by some other means). And at that point, where is the incentive to colonize other star systems? You're still probably not going to be able to move a meaningful part of your population, and if you can produce energy that cheaply you can sustain a large population in comfort at home. It's not inconceivable that there are advanced aliens all over the place, but that interstellar travel is basically limited to probes for pragmatic reasons. I think when the Fermi Paradox was brought in, there was still some lingering Malthusian idea that geometric population expansion was inevitable. We now know it very much isn't, at least for us. That changes things.
- kindle-dev 5y ago
  Even without FTL travel, just having constant acceleration at 1g is enough to travel the width of the galaxy in 12 years ship-time: https://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration#:~:text=At%20a%20constant%20acceleration%20of,would%20take%20about%2024%20years https://en.wikipedia.org/wiki/Space_travel_using_constant_ac....
  - rsynnott 5y ago
    That is a _huge_ 'just', tho. That's a lot of energy.
  - htrp 5y ago
    Welcome to the delta V problem....
  - jandrese 5y ago
    Try plugging 12 years of 1G acceleration into the Rocket Equation. If reactionless drives remain science fiction this mode of travel is flat impossible. There literally isn't enough mass in the solar system.
tgv 5y ago
1. People named "Wang" spread at a certain speed after coming into existence. 2. I don't know anybody named "Wang". 3. There are no people named "Wang" in the galaxy.
- deleted 5y ago
  [deleted]
TheOtherHobbes 5y ago
1. No they don't. Spreading at sub-FTL requires redundant self-correcting technology which can run for thousands of years without breaking down. This is about as achievable as FTL. Nothing lasts for thousands of years in deep space without being abraded, fried, nuked, or physically stressed to breaking point. 1b. Assuming you can solve 1. with some kind of magical alchemical spares-generating technology that never fails, the technology also has to be politically and philosophically stable, with reliable and persistent goals. Otherwise you'll get offshoots competing with each other. Which may mean undermining and perhaps even destroying previous settlements. How much independence is enough? How accurate are your initial models going to be? 2. We don't know that for sure. Absence of evidence is not evidence of absence. (We do know weird things happen, but we're not putting any serious effort into researching them, so we don't know what they are.) 3. There's no need to think about this after 1. and 2. Edit: to put this in context, you don't need to launch a probe. You need to launch a complete perfectly self-reproducing error-free space program. Which can also adapt to local resources. This seems... difficult.
- jandrese 5y ago
  If you have #1 you no longer need to go to a distant solar system to survive. By the time you have the tech you no longer have the need.
kenjackson 5y ago
Thanks for that simplification. I didn't get that at all from the abstract (as I didn't really follow much of it) :-( What is "volume appearance" BTW?

AutumnCurtain 5y ago

I felt like I could have used a better articulation of their definition of "loud" and "quiet" aliens, unless these are well known terms in the domain terms and I am just unfamiliar...

mannykannot 5y ago
The abstracts of papers are intentionally terse, which usually means they are addressed to people already familiar with the field. The paper itself is often more readable (though by no means always!) and it is often worth taking a look at the introduction and conclusion, at least. Here, we have 'To a first approximation, there are two kinds of aliens: quiet and loud. Loud (or “expansive”) aliens expand fast, last long, and make visible changes to their volumes. Quiet aliens fail to meet at least one of these criteria.'
deleted 5y ago
[deleted]

7thaccount 5y ago

The Fermi Paradox (where is everyone) has been debated for decades. There are so many possibilities such as great filters (early or late), prime directive, zoo hypothesis, dark forest hypothesis...etc etc. I'm sure you're aware of this, but I included just in case you wanted to explore in more depth. Some really good stuff.

AtlasBarfed 5y ago
I just heard about the dark forest a couple weeks ago. I believe it to be the model we should proceed with for safety. Assuming FTL isn't possible, the fact that dark energy makes large sections of the visible universe fundamentally inaccessible is probably a good thing. Otherwise that is a lot more of the universe that may be ahead of us and would stomp us like ants.
- betwixthewires 5y ago
  Unless something about life is fundamentally adversarial I wouldn't expect civilizations to be hostile to one another by default. You could make the argument that it does appear that life is fundamentally adversarial, seeing as in our one example all life feeds on other life, and to sustain life a creature must kill. I believe that's simple a circumstance of limited biomass in a closed system and so not fundamental, but you could argue that all civilizations probably get bootstrapped in this way and so it doesn't need to be fundamentally adversarial, but that all civilizations are accustomed to it so the distinction "fundamental" does not really matter. I'd disagree with that also, because a change in conditions to post scarcity changes conditioning and therefore behavior. You might also come up with a prisoners dilemma type scenario where a civilization doesn't want to be adversarial, but it doesn't know the intentions of others and so to protect itself, as a rule, destroys any that it finds. This is somewhat plausible but I don't really think likely because civilizations that evolved from abiogenetic origins separate from one another would likely have very very different behaviors that might not even overlap in many cases, so even if they were aware of each other they may not even be capable of interacting. It just does not make sense for a space faring civilization to be hostile. A requirement for space faring and a result of it is post scarcity; resources abound in the vast swathes of dead universe. There is no reason to even think competitively, barring some as yet undiscovered unobtanium so rare and so powerful that civilizations fight to extinction over it, but I doubt it. If anything, I'd think that a space faring civilization benefits the more it understands the universe, and learning about biospheres and civilizations with completely different evolutionary paths from abiogenesis would be more valuable than destruction of them.

Retric 5y ago

#1 has some huge assumptions built in. A civilization can travel a long distance without visiting every star system between it’s origin and destination. The limitation could be doubling time not travel time. Sure double every 100,000 years or less and in 4 million years you’ve run out of stars in the Milky Way which is an eye blink on cosmic timescales. But, a civilization that’s remote terraforming worlds that might greatly slow things down. How long does it take Cyanobacteria to create an oxygen atmosphere for example?

addingnumbers 5y ago

A turtle on the Galápagos Islands in 1450AD could use the same reasoning to conclude that no seafaring civilizations existed.

hansbo 5y ago
Yeah, but if humans keep existing for millions of years, then the probability for a turtle on the Galápagos Islands to live in the time between when humans started seafaring and when humans visited the islands would be extremely small compared to any other time period.
- addingnumbers 5y ago
  Since we know the conclusion to be false, any reasoning that would support this hypothetical turtle's conclusion that no seafarers existed in 1450 is inarguably an example of bad reasoning.
  - gpm 5y ago
    No, because the turtle is concluding that it's likely false, not definitely false. There happens to be a cosmic coincidence working against the turtle, but that doesn't mean that it was bad reasoning to conclude that the cosmic coincidence was very unlikely.
    - addingnumbers 5y ago
      The turtle is saying with certainty, not likelihood, that no seafarers exist, analogous with the explicit conclusion (3) in the top level comment
      - gpm 5y ago
        People are lazy when they speak, it's best to understand basically every claim as probabilistic (and meaning "almost certainly") even when it isn't stated as such. Certainly no-one would make the claim that "there are (definitely) no aliens in the galaxy" when we can't disprove the idea that aliens traveling at the speed of light just reached the galaxy (with our current understanding of physics). That doesn't mean you can't make the claim "there are (almost definitely) no aliens in the galaxy (because I just created the most amazing telescope ever and looked at every particle of matter in the galaxy and there were no aliens there)". The principle of charity demands that understand the bare claim that "there are no aliens in the galaxy" to mean something that is plausible, such as "there are almost certainly no aliens in the galaxy".

m3kw9 5y ago

The incentives and disincentives of exploring other systems is largely unknown. There could be huge risks in visiting other systems in which your own system of origin could be revealed if you happen to find another advanced civilization, I would think if a civilization is even predicted to be in a system, it will likely not be visited.

jamesdmiller 5y ago

Hanson doesn't think (2) and (3) follow because of the possibility of panspermia. It's possible that our galaxy is the only one in a billion light years that has given rise to life, but there could, because of panspermia, skill be a high probability that a planet in our galaxy outside our solar system has life. See this podcast Hanson did with me: https://soundcloud.com/user-519115521 https://soundcloud.com/user-519115521

blfr 5y ago
Your podcasts with Greg Cochran are quite possibly the most interesting (interesting stuff per minute) audio I've ever listened to.
- jamesdmiller 5y ago
  Thanks!

rsynnott 5y ago

I think (1) is probably the main questionable assumption, to be honest. Let's take as given that travel faster than light via some form of cheating isn't possible. Under that assumption, for mass interstellar travel in reasonable time, you would require the ability to produce vast amounts of cheap energy (either via fusion on the starship, or antimatter produced with cheap energy at home and used on the starship, or by some other means). And at that point, where is the incentive to colonize other star systems? You're still probably not going to be able to move a meaningful part of your population, and if you can produce energy that cheaply you can sustain a large population in comfort at home. It's not inconceivable that there are advanced aliens all over the place, but that interstellar travel is basically limited to probes for pragmatic reasons. I think when the Fermi Paradox was brought in, there was still some lingering Malthusian idea that geometric population expansion was inevitable. We now know it very much isn't, at least for us. That changes things.

kindle-dev 5y ago
Even without FTL travel, just having constant acceleration at 1g is enough to travel the width of the galaxy in 12 years ship-time: https://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration#:~:text=At%20a%20constant%20acceleration%20of,would%20take%20about%2024%20years https://en.wikipedia.org/wiki/Space_travel_using_constant_ac....
- rsynnott 5y ago
  That is a _huge_ 'just', tho. That's a lot of energy.
- htrp 5y ago
  Welcome to the delta V problem....
- jandrese 5y ago
  Try plugging 12 years of 1G acceleration into the Rocket Equation. If reactionless drives remain science fiction this mode of travel is flat impossible. There literally isn't enough mass in the solar system.

tgv 5y ago

1. People named "Wang" spread at a certain speed after coming into existence. 2. I don't know anybody named "Wang". 3. There are no people named "Wang" in the galaxy.

deleted 5y ago
[deleted]

TheOtherHobbes 5y ago

1. No they don't. Spreading at sub-FTL requires redundant self-correcting technology which can run for thousands of years without breaking down. This is about as achievable as FTL. Nothing lasts for thousands of years in deep space without being abraded, fried, nuked, or physically stressed to breaking point. 1b. Assuming you can solve 1. with some kind of magical alchemical spares-generating technology that never fails, the technology also has to be politically and philosophically stable, with reliable and persistent goals. Otherwise you'll get offshoots competing with each other. Which may mean undermining and perhaps even destroying previous settlements. How much independence is enough? How accurate are your initial models going to be? 2. We don't know that for sure. Absence of evidence is not evidence of absence. (We do know weird things happen, but we're not putting any serious effort into researching them, so we don't know what they are.) 3. There's no need to think about this after 1. and 2. Edit: to put this in context, you don't need to launch a probe. You need to launch a complete perfectly self-reproducing error-free space program. Which can also adapt to local resources. This seems... difficult.

jandrese 5y ago
If you have #1 you no longer need to go to a distant solar system to survive. By the time you have the tech you no longer have the need.

kenjackson 5y ago

Thanks for that simplification. I didn't get that at all from the abstract (as I didn't really follow much of it) :-( What is "volume appearance" BTW?