Assume life is rare/filtered, we straightforwardly expect to see what we see (empty sky).
Assume life is common and the singularity comes quickly and reliably, and colonization proceeds at the speed of light, then condition on the fact that we are pre-singularity. As far as I can tell, a random young civilization still expects empty skies, possibly slightly less because of the relatively small volume of spacetime where we would observe an approaching colonization wave.
So the observation of empty skies is only very weak evidence against life being common, given that this singularity stuff is sound.
The latter hypothesis is more specific, but I already believe all those assumptions (quick, reliable, and near-c).
Given that I take those singularity assumptions seriously (not just hypothetically), and given that we are where we are in the history of the universe, the fermi paradox seems resolved for me; I find it unlikely that a given young civilization would observe any other civilization, no matter the actual rate of life. If we did observe another isolated civilization it would be pretty much falsify my “quick,reliable, and lightspeed” singularity belief.
However, as you say, that “given that we are where we are in the history of the universe” is worrying. I predict most young civilizations to be early (because the universe gets burned up quickly), and I predict most civilizations to not be young, given that life is common. When we observe ourselves to be young and late (are we actually late?), fermi’s paradox results. I guess in this case fermi’s paradox is that we observed something that is a priori unlikely, and we wonder what unlikely alternate hypotheses this digs up (the above, for one). However, anthropics is very confusing...
I predict most young civilizations to be early (because the universe gets burned up quickly), and I predict most civilizations to not be young, given that life is common. When we observe ourselves to be young and late (are we actually late?), Fermi’s paradox results.
I still don’t get it.
Assume life is rare/filtered, we straightforwardly expect to see what we see (empty sky).
Assume life is common and the singularity comes quickly and reliably, and colonization proceeds at the speed of light, then condition on the fact that we are pre-singularity. As far as I can tell, a random young civilization still expects empty skies, possibly slightly less because of the relatively small volume of spacetime where we would observe an approaching colonization wave.
So the observation of empty skies is only very weak evidence against life being common, given that this singularity stuff is sound.
The latter hypothesis is more specific, but I already believe all those assumptions (quick, reliable, and near-c).
Given that I take those singularity assumptions seriously (not just hypothetically), and given that we are where we are in the history of the universe, the fermi paradox seems resolved for me; I find it unlikely that a given young civilization would observe any other civilization, no matter the actual rate of life. If we did observe another isolated civilization it would be pretty much falsify my “quick,reliable, and lightspeed” singularity belief.
However, as you say, that “given that we are where we are in the history of the universe” is worrying. I predict most young civilizations to be early (because the universe gets burned up quickly), and I predict most civilizations to not be young, given that life is common. When we observe ourselves to be young and late (are we actually late?), fermi’s paradox results. I guess in this case fermi’s paradox is that we observed something that is a priori unlikely, and we wonder what unlikely alternate hypotheses this digs up (the above, for one). However, anthropics is very confusing...
Fermi’s paradox also makes mention of the fact that there are billions of stars in the galaxy that are billions of years older than ours, many of them having habitable planets. Some reasons have prevented any of these from spawning a galactic colonization wave—and those reasons are of interest to us.
Yes and yes.