I mostly agree with you, but we may disagree on the implausibility of exotic physics. Do you consider all explanations which require “exotic physics” to be less plausible than any explanation that does not? If you are willing to entertain “exotic physics”, then are there many ideas involving exotic physics that you find more plausible than Catastrophe Engines?
In the domain of exotic physics, I find Catastrophe Engines to be relatively plausible since are already analogues of similar phenomena to Catastrophe Engines in known physics: for example, nuclear chain reactions. It is quite natural to think that a stronger method of energy production would result in even greater risks, and finally the inherent uncertainty of quantum physics implies that one can never eliminate the risk of any machine, regardless of engineering. Note that my explanation holds no matter how small the risk lambda actually is (though I implicitly assumed that the universe has infinite lifetime: for my explanation to work the expected life of the Catastrophe Engine has to be at most on the same order as the lifetime of the universe.)
It is also worth noting that there are many variants of the Catastrophe Engine hypothesis that have the same consequences but which you might find more or less plausible. Perhaps these Engines don’t have “meltdown”, but it is necessary that they experience some kind of interference from other nearby Engines that would prevent them from being built too closely to each other. You could suppose that the best Matrioshka Brains produce chaotic gravity waves that would interfere with other nearby Brains, for instance.
Personally, I find explanations that require implausible alien psychology to be less plausible than explanations that require unknown physics. I expect most higher civilizations to be indifferent about our existence unless we pose a substantial threat, and I expect a sizable fraction of higher civilizations to value expansion. Perhaps you have less confidence in our understanding of evolutionary biology than our understanding of physics, hence our disagreement.
For the sake of discussion, here is my subjective ranking of explanations by plausibility:
There are visible signs of other civilizations, we just haven’t looked hard enough.
Most expansionist civilizations develop near light-speed colonization, hence making it very unlikely for us to exist in the interval between when their civilization is visible and our planet has already been colonized
We happen to be the first technologically advanced civilization in our visible universe
Most artifacts are invisible due to engineering considerations (e.g. the most efficient structures are made out of low-density nanofibers, or dark matter).
Colonization is much, much more difficult than we anticipated.
Defensively motivated “berserkers”. Higher civs have delicate artifacts that could actually be harmed by much less advanced spacefaring species, hence new spacefaring species are routinely neutralized. It still needs to be explained why most of the universe hasn’t been obviously manipulated, hence “Catastrophe Engines” or a similar hypothesis. Also, it needs to be explained why we still exist, since it would be presumably very cheap to neutralize our civilization.
Some “great filters” lie ahead of us: such as nuclear war. Extremely implausible because you would also have to explain why no species could manage to evolve with better cooperation skills.
“Galactic zoo” hypotheses and other explanations which require most higher civilizations to NOT be expansionist. Extremely implausible because many accidentally created strong AIs would be expansionist.
I ignore the hypothesis that “we are in a simulation” because it doesn’t actually help explain why we would be the only species in the simulation.
A mechanism for explosive energy generation on a cosmic scale might also explain the Big Bang.
Invalidate:
Catastrophe engines should still be detectable due to extremely concentrated energy emission. A thorough infrared sky survey would rule them out along with more conventional hypotheses such as Dyson spheres.
If it becomes clear there is no way to exploit vacuum energy, this eliminates one of the main candidates for a new energy source.
A better understanding of the main constraints for engineering Matrioshka brains: if heat dissipation considerations already limit the size of a single brain, then there is no point in considering speculative energy sources.
I mostly agree with you, but we may disagree on the implausibility of exotic physics. Do you consider all explanations which require “exotic physics” to be less plausible than any explanation that does not? If you are willing to entertain “exotic physics”, then are there many ideas involving exotic physics that you find more plausible than Catastrophe Engines?
In the domain of exotic physics, I find Catastrophe Engines to be relatively plausible since are already analogues of similar phenomena to Catastrophe Engines in known physics: for example, nuclear chain reactions. It is quite natural to think that a stronger method of energy production would result in even greater risks, and finally the inherent uncertainty of quantum physics implies that one can never eliminate the risk of any machine, regardless of engineering. Note that my explanation holds no matter how small the risk lambda actually is (though I implicitly assumed that the universe has infinite lifetime: for my explanation to work the expected life of the Catastrophe Engine has to be at most on the same order as the lifetime of the universe.)
It is also worth noting that there are many variants of the Catastrophe Engine hypothesis that have the same consequences but which you might find more or less plausible. Perhaps these Engines don’t have “meltdown”, but it is necessary that they experience some kind of interference from other nearby Engines that would prevent them from being built too closely to each other. You could suppose that the best Matrioshka Brains produce chaotic gravity waves that would interfere with other nearby Brains, for instance.
Personally, I find explanations that require implausible alien psychology to be less plausible than explanations that require unknown physics. I expect most higher civilizations to be indifferent about our existence unless we pose a substantial threat, and I expect a sizable fraction of higher civilizations to value expansion. Perhaps you have less confidence in our understanding of evolutionary biology than our understanding of physics, hence our disagreement.
For the sake of discussion, here is my subjective ranking of explanations by plausibility:
There are visible signs of other civilizations, we just haven’t looked hard enough.
Most expansionist civilizations develop near light-speed colonization, hence making it very unlikely for us to exist in the interval between when their civilization is visible and our planet has already been colonized
We happen to be the first technologically advanced civilization in our visible universe
Most artifacts are invisible due to engineering considerations (e.g. the most efficient structures are made out of low-density nanofibers, or dark matter).
Colonization is much, much more difficult than we anticipated.
Defensively motivated “berserkers”. Higher civs have delicate artifacts that could actually be harmed by much less advanced spacefaring species, hence new spacefaring species are routinely neutralized. It still needs to be explained why most of the universe hasn’t been obviously manipulated, hence “Catastrophe Engines” or a similar hypothesis. Also, it needs to be explained why we still exist, since it would be presumably very cheap to neutralize our civilization.
Some “great filters” lie ahead of us: such as nuclear war. Extremely implausible because you would also have to explain why no species could manage to evolve with better cooperation skills.
“Galactic zoo” hypotheses and other explanations which require most higher civilizations to NOT be expansionist. Extremely implausible because many accidentally created strong AIs would be expansionist.
I ignore the hypothesis that “we are in a simulation” because it doesn’t actually help explain why we would be the only species in the simulation.
EDIT: Modified the order
Before we go further:
What specific observations and evidence does your idea explain, other than the Fermi paradox?
What specific observations and evidence, if we had them, would invalidate your idea?
For the original proposal:
Explain:
A mechanism for explosive energy generation on a cosmic scale might also explain the Big Bang.
Invalidate:
Catastrophe engines should still be detectable due to extremely concentrated energy emission. A thorough infrared sky survey would rule them out along with more conventional hypotheses such as Dyson spheres.
If it becomes clear there is no way to exploit vacuum energy, this eliminates one of the main candidates for a new energy source.
A better understanding of the main constraints for engineering Matrioshka brains: if heat dissipation considerations already limit the size of a single brain, then there is no point in considering speculative energy sources.