The Great Filter is the idea that, in the development of life from the earliest stages of abiogenesis to reaching the highest levels of development on the Kardashev scale, there is a barrier to development that makes detectable extraterrestrial life exceedingly rare. The Great Filter is one possible resolution of the Fermi paradox.
https://en.wikipedia.org/wiki/Great_Filter
The Fermi paradox is the discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high likelihood of its existence. As a 2015 article put it, “If life is so easy, someone from somewhere must have come calling by now.”
https://en.wikipedia.org/wiki/Fermi_paradox
Personally I think it’s photosynthesis. Life itself developed and spread but photosynthesis started an inevitable chain of ever-greater and more-efficient life. I think a random chain of mutations that turns carbon-based proto-life into something that can harvest light energy is wildly unlikely, even after the wildly unlikely event of life beginning in the first place.
I have no data to back that up, just a guess.
I think others wouldn’t bother with us until we started demonstrating likelihood of using dangerous tech or crazy exponential expansion.
I don’t remember well, but I think civilizations stationed their defensive or offensive tech away from their own civilizations, just dispersed around.
I think its explanation for why no one or anything has colonized the galaxy though is that if anyone shows signs of becoming that strong, they get zapped. Nobody wants to see a neighbor rise up into a behemoth, you get that bold you’re a threat.
My real preferred theory of why we don’t see other civilizations though is that I think they choose more inward, VR, computer-based evolution that doesn’t result in big mega structures.
Why do you think that, though? It doesn’t make sense, frankly - if you’re worried about competition evolving you shouldn’t wait until the last possible second to destroy it. That raises so many unnecessary risks of being slightly slow on the draw, and then it’s too late. Why not do it at the earliest convenience, when it’s super easy to do by comparison and there’s an incredibly long margin of error if you somehow miss the first couple of tries?
But they’re already doing it, you just said they’re putting outposts out there. If they can’t do that secretly then the Dark Forest doesn’t work in the first place. Placing a secret weapon base in another solar system is no different from placing a colony there.
As with many Fermi paradox solutions this one fails on account of requiring every single civilization (and every single subset of those civilizations) to all decide to do exactly the same thing, forever, with no exceptions. In a scenario like this what happens if a single subculture of a single advanced civilization decides for whatever reason that they prefer not to do that? They would be able to spread throughout the cosmos without opposition, everyone else is locked in their little dream boxes and therefore is basically irrelevant. It only needs to happen once, and the universe has been around for a very long time.
I agree, I don’t think they’d wait until the last possible moment when the civilization becomes super powerful or builds the mega weapon. I just mention it along the range of development to highlight the why.
I think they might let weaker civilizations keep going, though, just out of hope they wouldn’t be too mean. Also, zapping other civilizations when you don’t need to exposes yourself and your own aggression.
About the shift to VR /computer substrate worlds that wouldn’t have huge footprints, I agree that not all would do that, and it only takes one to go the big building and footprint route and it’s weird we don’t see it.
My guess then would be that maybe they do build big, but they just conceal well…? You get good enough tech at some point you can choose to be hard to see.