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.
Exponential functions. Seriously. You meet crisis after crisis, each having a risk of ending civilization, but that risk never goes away. It keeps multiplying and multiplying, until you realize the risk curve is approaching a vertical line
Why would risk go up over time? For humanity, we’re pretty much at the point that very little could end our species now.
Well except, obviously, for humanity. That’s our greatest enemy, and it seems to be shown more frequently.
We would be hard pressed to end our own species either. Even global thermonuclear war would end civilization but not our species.
