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.

    • FaceDeer@fedia.io
      link
      fedilink
      arrow-up
      5
      ·
      6 months ago

      How do they do it, though? It’s not really a valid solution unless you can explain how it works, otherwise it’s just “maybe some magic happens that kills civilizations.”

      Once a civilization has begun spreading to hundreds of other solar systems I have yet to hear of any plausible way to reliably “kill” it.

        • FaceDeer@fedia.io
          link
          fedilink
          arrow-up
          1
          ·
          edit-2
          6 months ago

          I don’t think you’ve thought through the logistics required for the sort of war where you’d just go around and shoot everyone who lives in hundreds of solar systems. Even assuming they do nothing at all to defend themselves, how do you even find them all?