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On the other hand, it might seem most likely that aliens should be here, given: - the vastness of space - the abundance of habitable worlds - the age of the

by zeven7 3y ago

On the other hand, it might seem most likely that aliens should be here, given: - the vastness of space - the abundance of habitable worlds - the age of the universe - the speed with which tools like von Neumann probes could proliferate the galaxy - the likelihood that somebody somewhere over millions of years would create a von Neumann probe (computer viruses didn't take long to make) - the observation that we are here so why is no one else? If we look around and see that we are alone, are we to assume no one else is there, or is it more likely they are and are hiding? There are good reasons to assume the group that comes to survive longest in the galaxy is also the one that is good at hiding. I think all these considerations more or less answer your first 5 points. For some of the remaining points, maybe there are very few real alien sightings in the UFO reports but they are very few. The vast majority are hoaxes / confused. Government is not involved but maybe covering up the fact that they have detected some things they can't explain.

jcranmer 3y ago
> - the speed with which tools like von Neumann probes could proliferate the galaxy > - the likelihood that somebody somewhere over millions of years would create a von Neumann probe (computer viruses didn't take long to make) The problem with this is no one has demonstrated any technology that can be used to make a von Neumann probe, and if you look at it from an engineering perspective, it's not clear that it's feasible at all. We are nowhere close to building machines that can build machines, much less ones that can do so when the inputs are "mine this rock", much less ones that can identify the rocks to be so mined, much less ones that are capable of being launched onto another planet, much less ones that can land on exoplanets, much less ones that can identify said exoplanets, much less ones that can remain in good working order for the entire journey. That's... a lot of steps that need to be met for a von Neumann probe to be possible in the first place, almost none of which are demonstrable anytime soon. Should any one of those things be impossible, or merely impracticable, then that means von Neumann probes themselves are so. Until it's demonstrated that there's a good reason to think that von Neumann probes should be possible to construct, I don't think it's reasonable to argue that we should assume they already exist.
- throwaway60607 3y ago
  Humans, animals, plants, microbes, etc are that technology. Life is self-replicating nanotechnology machines. If synthetic biology works - and we know it does, we have already created a synthetic cell - it's perfectly possible. Not to mention it could evolve on its own. Humans are Von Neumann probes in our environment.
jamilton 3y ago
If you calculate and come up with the answer that it's really likely we should be seeing life, is it more likely that life is hiding or that one of your assumptions is wrong? Maybe try adding confidence levels to your estimates or changing them to ranges? It might be that von Neumann probes are harder to make or slower than you're expecting. If you're really confident in all the values then your conclusion still makes sense. There's other factors that contribute to not seeing life in the universe. We have extremely limited ability to obverse exoplanets, my understanding is an exoplanet we're looking at could have life and we wouldn't know it. I think we're best suited to detecting life that outputs recognizable radio signals in our direction, which should be rare among all life.
- asdff 3y ago
  It's probably extremely likely that if there are other intelligent life out there it is hiding. Risks of things like contamination and extermination are massive, and one need only to look at our own history. Transoceanic trade was havoc enough on our own species when it emerged a few centuries ago, both in terms of loss of human life from violence and disease as well as native flora and fauna that was either exploited, cut out in favor of a cash crop, or outcompeted by an invasive species that came aboard those ships. Even today you can't do things like transport firewood due to the risk of spreading disease to different populations. I think we are in an especially dangerous position since we are just blaring out "Look at me!!!" with our radio emissions into the universe. Hopefully another species doesn't consider this as some brutish chesthumping of our confidence against conquest.
MrJohz 3y ago
Like I say, I'm all in board with accepting that aliens are likely to exist, that's the easy part of my list. And accepting that aliens can travel vast distances is also plausible, we just need to make them very technologically advanced in order to do so in reasonable time scales. And then possibly these very advanced aliens want to come to earth specifically out of curiosity or something? But the problem is with each premise you're making more assumptions, and as you get further those assumptions start contradicting each other. The aliens aren't making their presence known so clearly they want to hide in some way. But these super advanced aliens keep on getting spotted, so maybe they don't want to hide, or they're not that good at hiding? So maybe they don't have all that good technology? But now how do we get them to fly between solar systems to make the start of the theory work? And the further down the list you go, the more assumptions start to contradict each other, or become a step to far. But all of the assumptions are necessary because otherwise there's a gaping flaw in the whole idea.
- zeven7 3y ago
  > But these super advanced aliens keep on getting spotted, so maybe they don't want to hide, or they're not that good at hiding? So maybe they don't have all that good technology? But I addressed this by saying they're not getting spotted. This is an orthogonal discussion to the UFO discussion which started this thread. I think the vast majority of UFO sightings have a terrestrial explanation.

by zeven7 3y ago

jcranmer 3y ago

> - the speed with which tools like von Neumann probes could proliferate the galaxy > - the likelihood that somebody somewhere over millions of years would create a von Neumann probe (computer viruses didn't take long to make) The problem with this is no one has demonstrated any technology that can be used to make a von Neumann probe, and if you look at it from an engineering perspective, it's not clear that it's feasible at all. We are nowhere close to building machines that can build machines, much less ones that can do so when the inputs are "mine this rock", much less ones that can identify the rocks to be so mined, much less ones that are capable of being launched onto another planet, much less ones that can land on exoplanets, much less ones that can identify said exoplanets, much less ones that can remain in good working order for the entire journey. That's... a lot of steps that need to be met for a von Neumann probe to be possible in the first place, almost none of which are demonstrable anytime soon. Should any one of those things be impossible, or merely impracticable, then that means von Neumann probes themselves are so. Until it's demonstrated that there's a good reason to think that von Neumann probes should be possible to construct, I don't think it's reasonable to argue that we should assume they already exist.

throwaway60607 3y ago
Humans, animals, plants, microbes, etc are that technology. Life is self-replicating nanotechnology machines. If synthetic biology works - and we know it does, we have already created a synthetic cell - it's perfectly possible. Not to mention it could evolve on its own. Humans are Von Neumann probes in our environment.

jamilton 3y ago

If you calculate and come up with the answer that it's really likely we should be seeing life, is it more likely that life is hiding or that one of your assumptions is wrong? Maybe try adding confidence levels to your estimates or changing them to ranges? It might be that von Neumann probes are harder to make or slower than you're expecting. If you're really confident in all the values then your conclusion still makes sense. There's other factors that contribute to not seeing life in the universe. We have extremely limited ability to obverse exoplanets, my understanding is an exoplanet we're looking at could have life and we wouldn't know it. I think we're best suited to detecting life that outputs recognizable radio signals in our direction, which should be rare among all life.

asdff 3y ago
It's probably extremely likely that if there are other intelligent life out there it is hiding. Risks of things like contamination and extermination are massive, and one need only to look at our own history. Transoceanic trade was havoc enough on our own species when it emerged a few centuries ago, both in terms of loss of human life from violence and disease as well as native flora and fauna that was either exploited, cut out in favor of a cash crop, or outcompeted by an invasive species that came aboard those ships. Even today you can't do things like transport firewood due to the risk of spreading disease to different populations. I think we are in an especially dangerous position since we are just blaring out "Look at me!!!" with our radio emissions into the universe. Hopefully another species doesn't consider this as some brutish chesthumping of our confidence against conquest.

MrJohz 3y ago

Like I say, I'm all in board with accepting that aliens are likely to exist, that's the easy part of my list. And accepting that aliens can travel vast distances is also plausible, we just need to make them very technologically advanced in order to do so in reasonable time scales. And then possibly these very advanced aliens want to come to earth specifically out of curiosity or something? But the problem is with each premise you're making more assumptions, and as you get further those assumptions start contradicting each other. The aliens aren't making their presence known so clearly they want to hide in some way. But these super advanced aliens keep on getting spotted, so maybe they don't want to hide, or they're not that good at hiding? So maybe they don't have all that good technology? But now how do we get them to fly between solar systems to make the start of the theory work? And the further down the list you go, the more assumptions start to contradict each other, or become a step to far. But all of the assumptions are necessary because otherwise there's a gaping flaw in the whole idea.

zeven7 3y ago
> But these super advanced aliens keep on getting spotted, so maybe they don't want to hide, or they're not that good at hiding? So maybe they don't have all that good technology? But I addressed this by saying they're not getting spotted. This is an orthogonal discussion to the UFO discussion which started this thread. I think the vast majority of UFO sightings have a terrestrial explanation.