I think the post is well reasoned and useful in pointing out a few shortcoming in the paper, but fails to make the point you’re hoping for.
First and most importantly, with your preferred parameter choices, the 6% chance of no life in the Milky Way still almost certainly implies that the lack of alien signals is due to the fact that they are simply too far away to have been seen; the density of intelligence implied by that model is still very low. That means even your conclusion dissolves the initial “paradox.” At the most, it leaves the likelihood of the existence of a future great filter, based on the evidence of not seeing alien signals, far weaker than was previously argued for.
Second, a number of your arguments seem to say that we could have counterfactual evidence, and should use that as evidence. For example, “as far as we know it is equally possible that we could have found ourselves on a 9 billion year old Earth...” (it cannot, given the habitability window for life on earth,) or “Presumably life could evolve multiple times on the same planet...” (True, but not relevant for the model, since once life has emerged it passes this step—and we see no evidence of it happening on earth..) Even if these were correct, they should be reflected in the prior or model structure, as Robin Hanson suggests (“try once steps.”)
In any case, I think that a closer review of some of the data points is useful, and think the post was useful.
with your preferred parameter choices, the 6% chance of no life in the Milky Way still almost certainly implies that the lack of alien signals is due to the fact that they are simply too far away to have been seen
I haven’t run the numbers, but I wouldn’t be quite so dismissive. Intergalactic travel is probably possible, so with numbers as high as these, I would’ve expected us to encounter some early civilisation from another galaxy. So if these numbers were right, it’d be some evidence that intergalactic travel is impossible, or that something else strange is going on.
(Also, it would be an important consideration for whether we’ll encounter aliens in the future, which has at least some cause prio implications.)
(But also, I don’t buy the argument for these numbers, see my other comment.)
To respond to your substantive point, intergalactic travel is possible, but slow—on the order of tens of millions of years at the very fastest. And the distribution of probable civilizations is tilted towards late in galactic evolution because of the need for heavier elements, so it’s unclear that early civilizations are possible, or at least as likely.
“We don’t see time travelers. This means either time travel is impossible, or humanity doesn’t survive.
Evidence of the theoretical plausibility of time travel is therefore strong evidence that we will be extinct in the nearer term future.”
Except for the fact that those aren’t the only two possibilities. There could in fact be time travelers, but they remain unseen (either purposefully or not). And this would be a possibility for a long list of reasons .
Also, don’t lose the forest for the trees if you know what I mean.
Except for the fact that those aren’t the only two possibilities.
Right, but the other hypotheses need large complexity penalties for why the impact of time travelling is invisible, so lack of seeing time travelers is still pretty strong evidence.
I think the post is well reasoned and useful in pointing out a few shortcoming in the paper, but fails to make the point you’re hoping for.
First and most importantly, with your preferred parameter choices, the 6% chance of no life in the Milky Way still almost certainly implies that the lack of alien signals is due to the fact that they are simply too far away to have been seen; the density of intelligence implied by that model is still very low. That means even your conclusion dissolves the initial “paradox.” At the most, it leaves the likelihood of the existence of a future great filter, based on the evidence of not seeing alien signals, far weaker than was previously argued for.
Second, a number of your arguments seem to say that we could have counterfactual evidence, and should use that as evidence. For example, “as far as we know it is equally possible that we could have found ourselves on a 9 billion year old Earth...” (it cannot, given the habitability window for life on earth,) or “Presumably life could evolve multiple times on the same planet...” (True, but not relevant for the model, since once life has emerged it passes this step—and we see no evidence of it happening on earth..) Even if these were correct, they should be reflected in the prior or model structure, as Robin Hanson suggests (“try once steps.”)
In any case, I think that a closer review of some of the data points is useful, and think the post was useful.
I haven’t run the numbers, but I wouldn’t be quite so dismissive. Intergalactic travel is probably possible, so with numbers as high as these, I would’ve expected us to encounter some early civilisation from another galaxy. So if these numbers were right, it’d be some evidence that intergalactic travel is impossible, or that something else strange is going on.
(Also, it would be an important consideration for whether we’ll encounter aliens in the future, which has at least some cause prio implications.)
(But also, I don’t buy the argument for these numbers, see my other comment.)
To respond to your substantive point, intergalactic travel is possible, but slow—on the order of tens of millions of years at the very fastest. And the distribution of probable civilizations is tilted towards late in galactic evolution because of the need for heavier elements, so it’s unclear that early civilizations are possible, or at least as likely.
And somewhat similar to your point, see my tweet from a couple years back:
”We don’t see time travelers. This means either time travel is impossible, or humanity doesn’t survive.
Evidence of the theoretical plausibility of time travel is therefore strong evidence that we will be extinct in the nearer term future.”
“We don’t see time travelers. This means either time travel is impossible, or humanity doesn’t survive.
Evidence of the theoretical plausibility of time travel is therefore strong evidence that we will be extinct in the nearer term future.”
Except for the fact that those aren’t the only two possibilities. There could in fact be time travelers, but they remain unseen (either purposefully or not). And this would be a possibility for a long list of reasons .
Also, don’t lose the forest for the trees if you know what I mean.
Right, but the other hypotheses need large complexity penalties for why the impact of time travelling is invisible, so lack of seeing time travelers is still pretty strong evidence.