I’m not sure I understand the second question. I would have thought both updates are in the same direction: the fact that we’ve survived on Earth a long time tells us that this is a planet hospitable to life, both in terms of its life-friendly atmosphere/etc and in terms of the rarity of supervolcanoes.
We can say, on anthropic grounds, that it would be confused to think other planets are hospitable on the basis of Earth’s long and growing track record. But as time goes on, we get more evidence that we really are on a life-friendly planet, and haven’t just had a long string of luck on a life-hostile planet.
The anthropic shadow argument was an argument along the lines, “no, we shouldn’t get ever more convinced we’re on a life-friendly planet over time (just on the evidence that we’re still around). It is actually plausible that we’ve just had a lucky streak that’s about to break—and this lack of update is in some way because no one is around to observe anything in the worlds that blow up”.
Habryka referred me to https://forum.effectivealtruism.org/posts/A47EWTS6oBKLqxBpw/against-anthropic-shadow , whose “Possible Solution 2” is what I was thinking of. It looks like anthropic shadow holds if you think there are many planets (which seems true) and you are willing to accept weird things about reference classes (which seems like the price of admissions to anthropics). I appreciate the paper you linked for helping me distinguish between the claim that anthropic shadow is transparently true without weird assumptions, vs. the weaker claim in Possible Solution 2 that it might be true with about as much weirdness as all the other anthropic paradoxes.
Eli Rose was the one who linked to it, to give credit where it’s due : )
I agree that those are different claims, but I expect the weaker claim is also not true, for whatever that’s worth. The claim in Toby Crisford’s Possible Solution 2, as I understand it, is the same as the claim I was making at the end of my long comment: that one could construct some anthropic principle according to which the anthropic shadow argument would be justified. But that principle would have to be different from SSA and SIA; I’m pretty sure it would have to be something which no one has argued for; and my guess is that on thinking about it further most people would consider any principle that fits the bill to have significantly weirder implications than either SSA or SIA.
I’m not sure I understand the second question. I would have thought both updates are in the same direction: the fact that we’ve survived on Earth a long time tells us that this is a planet hospitable to life, both in terms of its life-friendly atmosphere/etc and in terms of the rarity of supervolcanoes.
We can say, on anthropic grounds, that it would be confused to think other planets are hospitable on the basis of Earth’s long and growing track record. But as time goes on, we get more evidence that we really are on a life-friendly planet, and haven’t just had a long string of luck on a life-hostile planet.
The anthropic shadow argument was an argument along the lines, “no, we shouldn’t get ever more convinced we’re on a life-friendly planet over time (just on the evidence that we’re still around). It is actually plausible that we’ve just had a lucky streak that’s about to break—and this lack of update is in some way because no one is around to observe anything in the worlds that blow up”.
Habryka referred me to https://forum.effectivealtruism.org/posts/A47EWTS6oBKLqxBpw/against-anthropic-shadow , whose “Possible Solution 2” is what I was thinking of. It looks like anthropic shadow holds if you think there are many planets (which seems true) and you are willing to accept weird things about reference classes (which seems like the price of admissions to anthropics). I appreciate the paper you linked for helping me distinguish between the claim that anthropic shadow is transparently true without weird assumptions, vs. the weaker claim in Possible Solution 2 that it might be true with about as much weirdness as all the other anthropic paradoxes.
Eli Rose was the one who linked to it, to give credit where it’s due : )
I agree that those are different claims, but I expect the weaker claim is also not true, for whatever that’s worth. The claim in Toby Crisford’s Possible Solution 2, as I understand it, is the same as the claim I was making at the end of my long comment: that one could construct some anthropic principle according to which the anthropic shadow argument would be justified. But that principle would have to be different from SSA and SIA; I’m pretty sure it would have to be something which no one has argued for; and my guess is that on thinking about it further most people would consider any principle that fits the bill to have significantly weirder implications than either SSA or SIA.