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Dissolving the Fermi Paradox

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Re: Dissolving the Fermi Paradox

#91

Post by 08-15 »

mirimir wrote: post #26
jerf wrote: post #22

Earlier quoted context omitted.

The article is not about picking parameters. The article is one meta layer up from that; they examine the distribution of parameters. I can't guarantee this is novel paper in general, but it's not something I've seen treated this formally before. I mean, it roughly conforms to what I've been saying for a while, but I only worked the math very intuitively and in a manner that could have been flawed, so I get no credit…

OK, picking distributions. I can't imagine that there's enough data to even do that.

There is quite a bit of literature on picking distributions in the absence of observations. "Probability Theory: The Logic Of Science" by E. T. Jaynes has a whole chapter on "ignorance priors", where he shows how to pick prior distributions in the absence of quantitative information.

Generally, these ignorance priors are improper (unnormalizable) distributions. One example is scale parameters, where the approriate prior is 'ds/s', which makes any order of magnitude equally probable. It doesn't have a mean, and it favors small values. A tiny bit of evidence will immediately turn it into a proper posterior distribution; I think this prior has zero information content.

Of course, if one applies that approach to the Drake equation, one ends up with an equally uninformative posterior distribution, unless one can add evidence for each single variable. But that evidence just isn't there for some of them, so the result remains the same: It's impossible to estimate N, but it's probably very small. As it should be, given the total lack of data.

Re: Dissolving the Fermi Paradox

#93

Post by bena »

Buttons840 wrote: post #25
transfire wrote: post #3

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." There is no way we are alone.

Every once in a while we see a headline that says something like "There are more planets than we previously thought", or "There are more galaxies than we previously thought". When people see these they often conclude that the odds that life exists elsewhere are greater than previously thought, but it's also perfectly logical to see those headlines and concludes that the odds of life forming are lower than previously…

We're still working out how to get to Mars. Currently it will take close to a year. The longest time someone has spent in space has been just over a year.

It is not easy. It is not quick.

Even if we travel at the fastest possible speed, it takes 4 years to get to the next star. So, where are they? Too far away to reach.

The assumption that these problems are possible to overcome is a big one.

Re: Dissolving the Fermi Paradox

#94

Post by Sniffnoy »

I'm going to repost the same comment I made on Reddit:

This is quite interesting. It certainly sounds like this does dissolve the Fermi paradox, as they say. However, I think the key idea in this paper is actually not what the authors say it is. They say the key idea is taking account of all our uncertainty rather than using point estimates. I think the key idea is actually realizing that the Drake equation and the Fermi observation don't conflict because they're answering different questions.

That is to say: Where does this use of point estimates come from? Well, the Drake equation gives (under the assumption that certain things are uncorrelated) the expected number of civilizations we should expect to detect. Here's the thing -- if we grant the uncorrelatedness assumption (as the authors do), the use of point estimates is entirely valid for that purpose; summarizing one's uncertainty into point estimates will not alter the result.

The thing is that the authors here have realized, it seems to me, that the expected value is fundamentally the wrong calculation for purposes of considering the Fermi observation. Sure, maybe the expected value is high -- but why would that conflict with our seeing nothing? The right question to ask, in terms of the Fermi observation, is not, what is the expected number of civilizations we would see, but rather, what is the probability we would see any number more than zero?

They then note that -- taking into account all our uncertainty, as they say -- while the expected number may be high, this probability is actually quite low, and therefore does not conflict with the Fermi observation. But to my mind the key idea here isn't taking into account all our uncertainty, but asking about P(N>0) rather than E(N) in the first place, realizing that it's really P(N>0) and not E(N) that's the relevant question. It's only that switch from E(N) to P(N>0) that necessitates the taking into account of all our uncertainty, after all!

[Note afterward: Over on Reddit, hxka points out that that should be P(N>1), not P(N>0). Or really it should be P(N>1|N>0)...]

Re: Dissolving the Fermi Paradox

#95

Post by carapace »

We're in quarantine.

To other life forms humans look like H.R. Giger's xenomorph aliens from the movies.

We're obviously intelligent, yet we absolutely refuse to communicate with other life forms. we're not even interested in the possibility.

We consume other organisms with rapacious abandon, converting them into more of ourselves as fast as we can. We are strip-mining the oceans of protein, our chattel livestock out-mass all other land animals by several times, and still we consume. We clearcut forests leaving patterns visible from space.

We cover everything with asphalt and concrete to create huge sprawling nests that are inimical to life other than our own (and a few species that can live with us.) Again, this is clearly visible from space.

From orbit we look just like a disease.

There's a place in Washington (state), a lake, where the UFOs take off and land (underwater) and the cheeky fuckers will wave back at you from windows in the ships.

We're not alone. We just suck.

Re: Dissolving the Fermi Paradox

#96

Post by sulam »

gmuslera wrote: post #75

The reasoning seem to be "as we don't have enough data, lets conclude whatever I want". The Fermi paradox assumes that if there are aliens more advanced than us somewhere for a long time, they should be here by now. Maybe more advanced technology enables interstellar travel (maybe not, maybe is not practical at all), maybe they may not have all our motivations (expansion, technological advancement in our own focus, e…

>Maybe more advanced technology enables interstellar travel (maybe not, maybe is not practical at all)

We have practical interstellar travel today if you don't artificially constrain your thinking to sending blobs of mostly water with lifespans measured in decades.

Re: Dissolving the Fermi Paradox

#97

Post by maxerickson »

sulam wrote: post #96
gmuslera wrote: post #75

The reasoning seem to be "as we don't have enough data, lets conclude whatever I want". The Fermi paradox assumes that if there are aliens more advanced than us somewhere for a long time, they should be here by now. Maybe more advanced technology enables interstellar travel (maybe not, maybe is not practical at all), maybe they may not have all our motivations (expansion, technological advancement in our own focus, e…

>Maybe more advanced technology enables interstellar travel (maybe not, maybe is not practical at all) We have practical interstellar travel today if you don't artificially constrain your thinking to sending blobs of mostly water with lifespans measured in decades.

What are your parameters for practical?

Like, how much mass, how fast, cost, etc?

Re: Dissolving the Fermi Paradox

#98

Post by jl2718 »

I would rephrase the question as: What are reasonable bounds on the number of intelligent civilizations, given that we have observed exactly one in the archeological record of our own planet, and no others elsewhere with current technology?

So, tiny sliver of time over billions of years, and communications technology that only reaches to a few nearby stars.

Trying to use probability of certain chemistry is, I think, highly subject to errors and failure to consider some alternative possibilities.

Life itself, however, is a totally different equation because it’s nearly as old as the earth. This might suggest that there is a lot of it out there.

Re: Dissolving the Fermi Paradox

#99

Post by strkek »

TeMPOraL wrote: post #58
jandrese wrote: post #46

Earlier quoted context omitted.

The Drake equation is the epitome of garbage in garbage out. Trying to draw a line using a single data point. There was recent news from NASA about the discovery of organic molecules on Mars and the possibility of life there at some point in the past. Discovery that life once existed on Mars would blow up the assumptions in the Drake equation. As for the Fermi paradox I'm still of the opinion that its solution is sim…

Also, VR. I already fear the future of humanity is not exploring strange new worlds, but creating virtual ones, and converting the solar system into more computronium. (And the weird thing about that is that I feel it's a bad thing for some reason, but I can't articulate a coherent argument against it.)

As long as humans continue to be like we have been so far, i.e. with the mentality of destroying our own planet and not caring about it, or committing crimes like kidnapping, etc... as long as there are individuals like that, every time we humans learn something new, things will inevitably turn way more scarier.

Whether it's colonizing other planets or making a full-dive VR; just thinking about the time when we can do any of these things gives me a headache.

Re: Dissolving the Fermi Paradox

#100

Post by psychometry »

goatlover wrote: post #39
psychometry wrote: post #35

Does anyone else find this question totally uninteresting? There's no discussion to be had about this paradox that doesn't devolve into an N=1 predictive model.

I find it interesting because if N=1, then we're an incredibly statistical fluke, and yet there's no reason to suppose that our solar system or planet is that much of an anomaly.

Maybe for me the issue is that since N=1, we have nowhere near enough information to construct reasonable priors on the equation's parameters. This makes the variance in the outcome explode. The ballpark is so huge that basically any interpretation is fair game.
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