I’d like to rescue/clarify Mitchell’s summary. The paper’s resolution of the Fermi paradox boils down to “(1) Some factors in the Drake equation are highly uncertain, and we don’t see any aliens, so (2) one or more of those factors must be small after all”.
(1) is enough to weaken the argument for aliens, to the point where there’s no paradox anymore. (2) is basically Section 5 from the paper (“Updating the factors”).
The point you raised, that “expected number of aliens is high vs. substantial probability of no aliens” is an explanation of why people were confused.
I’m making this comment because if I’m right it means that we only need to look for people (like me?) who were saying all along “there is no Fermi paradox because abiogenesis is cosmically rare”, and figure out why no one listened to them.
The point you raised, that “expected number of aliens is high vs. substantial probability of no aliens” is an explanation of why people were confused.
Right, I think it’s important to separate out the “argument for X” and the “dissolving confusions around X” as the two have different purposes.
I’m making this comment because if I’m right it means that we only need to look for people (like me?) who were saying all along “there is no Fermi paradox because abiogenesis is cosmically rare”, and figure out why no one listened to them.
I think the important thing here is the difference between saying “abiogenesis is rare” (as an observation) and “we should expect that abiogenesis might be rare” (as a prediction) and “your own parameters, taken seriously, imply that we should expect that abiogenesis might be rare” (as a computation). I am not aware of papers that did the third before this, and I think most claims of the second form were heard as “the expected number of aliens is low” (which is hard to construct without fudging) as opposed to “the probability of no aliens is not tiny.”
But this paper does not talk about “your own parameters.” The parameters it uses are the range of published parameters. Saying that people should have used that range is exactly the same as saying that people should not have ignored the extremists. (But I think it’s just not true that people ignored the extremists.)
If interstellar panspermia is possible, “abiogenesis is cosmically rare” is not an explanation, and our Galaxy could be populated by aliens of approximately our civilisational age and the same basic genetic code.
Good point. In that case the Drake equation must be modified to include panspermia probabilities and the variance in time-to-civilization among our sister lineages. I’m curious what kind of Bayesian update we get on those...
I’d like to rescue/clarify Mitchell’s summary. The paper’s resolution of the Fermi paradox boils down to “(1) Some factors in the Drake equation are highly uncertain, and we don’t see any aliens, so (2) one or more of those factors must be small after all”.
(1) is enough to weaken the argument for aliens, to the point where there’s no paradox anymore. (2) is basically Section 5 from the paper (“Updating the factors”).
The point you raised, that “expected number of aliens is high vs. substantial probability of no aliens” is an explanation of why people were confused.
I’m making this comment because if I’m right it means that we only need to look for people (like me?) who were saying all along “there is no Fermi paradox because abiogenesis is cosmically rare”, and figure out why no one listened to them.
Right, I think it’s important to separate out the “argument for X” and the “dissolving confusions around X” as the two have different purposes.
I think the important thing here is the difference between saying “abiogenesis is rare” (as an observation) and “we should expect that abiogenesis might be rare” (as a prediction) and “your own parameters, taken seriously, imply that we should expect that abiogenesis might be rare” (as a computation). I am not aware of papers that did the third before this, and I think most claims of the second form were heard as “the expected number of aliens is low” (which is hard to construct without fudging) as opposed to “the probability of no aliens is not tiny.”
But this paper does not talk about “your own parameters.” The parameters it uses are the range of published parameters. Saying that people should have used that range is exactly the same as saying that people should not have ignored the extremists. (But I think it’s just not true that people ignored the extremists.)
If interstellar panspermia is possible, “abiogenesis is cosmically rare” is not an explanation, and our Galaxy could be populated by aliens of approximately our civilisational age and the same basic genetic code.
Good point. In that case the Drake equation must be modified to include panspermia probabilities and the variance in time-to-civilization among our sister lineages. I’m curious what kind of Bayesian update we get on those...
In fact, not a mine idea, I read an article about it by Panov—https://www.sociostudies.org/almanac/articles/prebiological_panspermia_and_the_hypothesis_of_the_self-consistent_galaxy_origin_of_life/