Personally I think this is wrongheaded (similar to the big alien guy [1]) because you don’t really account for your epistemological risk- the risk that the way in which you are thinking about this may be wrong.
More broadly, I suspect that there is a defect in education on this matter. You are commonly given rules and variables, and have to figure out the variables given the rules. But you are usually given all the rules and not typically required to figure them out, and not misled with respect to them.
This is quite different from reality where the rules are often as unknown as the variables, and there can be great uncertainty about what they are.
I wonder if it is a result of institutionalized education that students are not taught to mistrust the rules they are given?
> Life exists here on Earth, and our standard best theories say that this was not a miracle, nor was Earth the only place such things could happen. Furthermore, our universe also seems very large (perhaps infinite). Thus our standard best theories predict that advanced life has appeared and will appear many times out there.
I'm no expert on abiogenesis, but my understanding was that we're nowhere near being able to estimate its probability like this.
Sure it could be that life commonly emerges from Earth-like conditions when given enough time, but it could also be that life requires such an extraordinarily unlikely sequence of events (to get started and then thrive) that it only occurs on one planet in every googolplex universes.
> [10% chance that] A sibling star gave rise to a long-lived advanced civ long before now
I'd like to see the reasoning behind this estimate (or any of the other numbers given).
While we do not know the probability of abiogenesis, we can make an educated guess as to the range of probable likelihoods. ie, the probability of the probability.
I read a paper on this a while ago, which I cannot find now, but it places the likelihood at some meaningful percentage per million years, which in aggregate across several orders of magnitude of planets, makes life elsewhere in the universe very likely.
It uses the statistical notion that Earth should not be modeled as a single data point, but as a series that you integrate over, and concludes that since life emerged so soon after Earth became habitable, that the emergence of life is likely likely (the probability of the probability) - within the lifespan of a similar star.
To give you a more clear example...
Imagine a handing a subject a bag containing a die with an unknown number of sides. You ask a subject to reach into the bag, pull out a die and keep rolling it until he gets a 1. ...and then report to you only the number of times it took to roll a one.
In statistics, can you infer a probability on the number of sides of that die, based upon how long it took the subject to reach a 1 - even if the experiment is only performed once? The answer is YES. If the subject only had to roll the die twice to get a 1, you can estimate that the die probably had very few sides. Similarly, if the subject that it took a million tries to roll a 1, you can very comfortably say that the die was not 2 sided (a coin).
In the same vein, since life appeared on Earth in the few hundred(s) of millions of years after it became habitable, then the likelihood is probably not close enough to zero to rule out life in the cosmos.
Treating Earth as one data point is an unwise oversimplification.
> While we do not know the probability of abiogenesis, we can make an educated guess as to the range of probable likelihoods. ie, the probability of the probability.
No, we can't.
> Treating Earth as one data point is an unwise oversimplification.
It is one data point. We have no other. We can't know anything about any others.
Doing anything else is wishful thinking hidden in fancy methodology, just like this article. It is all nonsense.
We really, really do not know a single thing about the likeliness of life appearing. Not until we find a second data point.
So the government started leaking blurry UFO videos that look like webcam footage of Sasquatch at exactly the same time that China passed through U.S. in military supremacy. Seems like U.S. is just trying to trick China into wasting their money.
There's a debate? I thought it was still pretty obvious they're a long way from getting even close. They may be at the point where they have tactical superiority over Taiwan, but that's about it.
Mr Hanson's been posting excellent arguments for a while that amount to "there might be life other than ours," and its increasingly reminding me of arguments over religion. I agree with him, and am enjoying his logic and reason, but I think he's arguing against faith here.
Either one is open to the idea that Earth life is not alone, or one isn't; and Reason alone isn't a big enough engine to pull one over the hump to the other side.
I wonder what the "earth is unique" folks will do if faced with proofs; declare war or declare themselves slaves? I doubt they'll be able to handle "peaceful coexistence," which I'd say is a damned good reason for the aliens to stay hidden.
It's entirely possible to believe that alien life elsewhere in the universe is possible or even likely, but to be extremely skeptical of supposed UFO sightings.
Indeed; but having seen the comments and counter-arguments Hanson keeps drawing, I'd say thats not a common position. I see the split as "earth life is only life"; but that's not a great way of expressing it...
Better might be "known life is all life" or "all life is known". My particular peculiar kink in this discussion is that I think there's whole orders of life and modes of being, on this planet, that we have at most barely perceived and roughly imagined.
Not me, totally on board with whole modes of being and life that we are unaware of and could possibly be unable to perceive at the present moment, even on this planet.
Very interested in models to help explore/experiment this space rather than those that don't allow to knowledge to be built upon for future proofs or falsification.
Applying fancy methodology to numbers you make up helps you think about the numbers you make up. You go from "I don't believe UFOs are aliens" to a more refined opinion of "I don't believe UFOs are aliens because I don't believe X, Y, Z is very likely".
On the other hand, priors are only a matter of the subject. If there are aliens operating UFOs they want or not want to contact us. If they want to, what are they waiting for? If they don't want to, how come our technology can routinely spot their spacefaring machines? Are they that clumsy?
Aliens trolling us could be a viable intention. Billion year old von-neumann probes probably get bored. Or perhaps alien societies are ideologically split and one sect wants to provoke a good or bad response from us per some agenda. Or we’re being subject to CentauriU’s Delta Tau Chi pledge week prank.
And so far they’ve just been lucky and some complex conspiracy requiring they have a fuzzy polaroid filter on all our systems is not required.
More broadly, I suspect that there is a defect in education on this matter. You are commonly given rules and variables, and have to figure out the variables given the rules. But you are usually given all the rules and not typically required to figure them out, and not misled with respect to them.
This is quite different from reality where the rules are often as unknown as the variables, and there can be great uncertainty about what they are.
I wonder if it is a result of institutionalized education that students are not taught to mistrust the rules they are given?
[1] https://news.ycombinator.com/item?id=27359203