On the other hand, stars are extremely wasteful. A technological civilization will, eventually, encase their sun in an energy extracting Dyson swarm. So why isn't the sky full of dim uniform-distribution infrared blobs?
The above link is about AI, but it could apply to any alien species just as well.
Any organism living in a thermodynamic universe and subject to competition and evolutionary pressures will develop instinctual drives that align with resource acquisition, replication, and survival. As the above link details this surprisingly holds true even when you remove evolution and consider designed minds.
Even if a hypothetical civilization didn’t care about resource acquisition, replication and survival, they’d be out-competed by one which did. So where is that civilization’s ever expanding sphere of Dyson clouds?
The authors referenced at the above link don't use that seemingly unwarranted tone of certainty. I can't see anything in Omohundro's papers of anything like the same flavour, and Bostrom's conclusion is the sensible-sounding
It should be emphasized that the existence of convergent instrumental reasons, even if they apply to and are recognized by a particular agent, does not imply that the agent’s behavior is easily predictable. An agent might well think of ways of pursuing the relevant instrumental values that do not readily occur to us. This is especially true for a superintelligence, which could devise extremely clever but counterintuitive plans to realize its goals, possibly even exploiting as-yet undiscovered physical phenomena. What is predictable is that the convergent instrumental values would be pursued and used to realize the agent’s final goals, not the specific actions that the agent would take to achieve this.
I’m not what you’re picking up on other than academic prose. The very quote you give is very certain that convergent intermediate goals would be pursued.
There are a lot of problems with the dark forest hypothesis, the most critical for this purpose being that it is not a stable outcome. A civilization with the capability to create a Dyson sphere and harness the power of an entire star could easily defeat any invader attracted to their presence. E.g. with gamma-ray lasers that fry anything and everything that might be hostile.
Even with the most advanced technology we can imagine, you can't expect to be able to detect a neighboring civilization, cross the gap between stars with an invading fleet, and arrive with enough power to overwhelm defenses every single time. Local development of solar system resources is inherently an exponential process, whereas mustering of interstellar resources is quadratic. A potential dark forest / wolf entity (I much prefer Alastair Reynolds over Liu Cixin) would have to arrive right within the (cosmically brief) window of opportunity in which a developing civilization announces its presence but before it achieves Type II status on the Kardashev scale. Statistically, someone will eventually be lucky enough to avoid the wolves long enough to get that far, and then they'd have the capability to defend themselves from any plausible enemy.
Where are the Dyson spheres of those civilizations?
I have wondered about this too. I suppose the reasoning is that every solar system has a massive source of energy in the middle of it, and that mega civilizations would be stupid to not utilize it.
Sounds probable, but I can see many possible reasons not to bother. Not to mention it is speculating about technology so far ahead of our own that it seems silly. 50's predictions of rocket belts and nuclear powered cars come to mind.
> 50's predictions of rocket belts and nuclear powered cars come to mind.
These are different kind of predictions. Rocket belts could work, but they don't make economic sense and there's a strong safety argument against it. It's the same reason we don't have flying cars either.
Nuclear-powered cars could have worked; the failure wasn't predicting technology or its feasibility, but that nobody figured out humanity will collectively go insane and irrationally refuse to develop use of nuclear energy.
Dyson spheres are a pretty obvious thing to do - every star is a free, self-maintaining fusion generator that just wastes almost 100% of its output. So the argument is really that when a civilization's need for energy gets larger than what can be supplied by burning whatever stuff they have on their planet, the next obvious step is their star. Barring some magic tech breakthroughs like pulling energy from "subspace" or whatever, you have a rather solid argument that's essentially: "as long as life is not limited from growing, it will eventually start blotting out the sun it orbits".
The 50s analogy is only to point out how we like to extrapolate contemporary technical understanding into the future. The envisioned dyson spheres I've seen look like our current understanding and use of photovoltaics extrapolated in the same way.
I don't disagree that the core idea of harnessing the suns energy seems likely. As the parent poster said, it's just the absolute confidence that people seem to have on the subject that's a bit curious.
Maybe breakthroughs in energy generation will make it not worth the effort? Maybe becoming interstellar makes it obsolete since the energy requirements for a given civilization are spread thinner? Maybe there are other ways to harness the solar energy that would not show the same signs as we predict? Maybe civilizations trend to energy efficiency instead of just increased usage?
Especially when the Earth is getting effectively zero of the sun's energy now, and humanity is so incapable of harnessing even that minuscule amount, that killing off their entire planet is still a much talked about possibility.
Such observation supposes that our timeline matches theirs (taking into account the delay due to lightspeed). We weren't capable of such observation until about a few decades ago, other civilization could have existed and vanished billions of years ago, or billions of years in the future, or are so distant that they're outside of our obserable universe (if they ever was within it).
Or energy is not such a big deal anymore once you've reached a certain stage of technological advancement, so it's not the right criteria.
Civilizations won’t go extinct once there are interstellar, thanks to the speed of light balkanizing any such civilization, and thereby providing redundancy.
I followed Tabby's Star news for a while (star that showed massive dips, speculation was that it is a dyson sphere being built).
Most scientists believe that even if the star is encased in Dyson sphere that there would be excess infrared emissions as the sphere would need to vent heat. It would be hotter than surrounding space and thus visible.
They are thus trying to detect such stars with higher mass and IR excess than expected, but so far there are not many candidates.
You cannot simply absorb all the energy of the star and never emit it. The waste heat has to go somewhere. An efficient Dyson sphere would still emit lower energy infrared radiation in a way that would be detectable from out space-based observatories.
One must assume either the aliens aren't there, or that the idea is not worth it for reasons we haven't discovered yet. Maybe planetside fusion power is just more efficient. Maybe they can harvest energy from black holes or something.
Because there's no other intelligent life out there.
You know that. But it bears mention, for others following along, that rampant artificial intelligence or similar does not count as a great filter candidate, because it would be just as visible as the life it's replacing.
That doesn't leave a lot of fast-acting filters that could still be in our future, to be honest. Nuclear war? Sure, but we've avoided it too long for that to be a good one either.
Artificial intelligence would necessarily have different physical needs than biological life. We can expect even our own AI to be a bit alien to our ways of thinking. Alien created AI would be completely alien to us. With different needs and different motivations, what evidence do we even look for, and if it is pervasive, how do we know we aren’t looking right at it?
It would still exist in the same universe subject to the same laws of thermodynamics, and would still extract energy from fusion stars in a way that leaves an unmistakable technology signature.
It would be subject to the same laws, barring novel physics (like extracting energy from dark matter or some other process we don't yet understand). But a single AI could be smarter than 10 billion humans and consume less energy, need less space, and not care about expanding out into the stars. They could coast around their host star indefinitely and when they eventually needed to leave (which could be never), they could store energy and make a long, slow trek to another star. Imagine trying to find an asteroid-sized object in interstellar space.
