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I dunno, I kind of doubt that Eric Drexler is clueless or malicious. Maybe if you read the paper and understood their approach you'd have less of a knee-jerk reaction. They are arguing (as pointed out in comments elsewhere) that the math on probabilities should be using distributions, and this is what they do, and they go on to show that the resulting probabilities are far, far lower than the simplistic Drake equation would suggest.

> the math on probabilities should be using distributions

Do you really think that this is novel in any way whatsoever? There is some yearly chance of nuclear war, and I don't know about geopolitics so I have a prior distribution over that yearly chance. Should I cite this paper?

I actually really like the authors, and for all I know the paper may have some new insights or perform a calculation that hasn't been done before, but let's not pretend that prior distributions over probabilities is a new idea.

What does novelty have to do with dissolving the Fermi Paradox?

Is Fermi is some well established science, with repeated experimental proof, upon which numerous other conjectures have been built on?

Does it really require a novel approach to attack its basis?

The top-level commenter wrote

> Everyone considered this option. From the very first day the paradox was posed. We don't know the parameters well, it's within our margin of error that no one else is out there, so it's an option.

And the person I replied to was rebutting this point (that the approach is obvious and considered long ago).

It's fine to write review articles, or clean up old arguments and repackage them, but it shouldn't be presented as a new idea, and in particular it should point to the prior work.

I don't think they are claiming to have invented math on probability distributions and I didn't mean to suggest that that is what is novel about this paper. They used a different, more powerful technique to look at the math of the Fermi Paradox and came to a conclusion different than that following from the normal treatment of the Drake equation. That's a reasonable contribution, IMO.

But if you just formalize an approach that was considered by everyone right from the start, this isn't coming to a different conclusion. (https://news.ycombinator.com/item?id=17304389)

doubt that Eric Drexler is clueless or malicious

Someone however, does not.

https://scottlocklin.wordpress.com/2010/08/24/nano-nonsense-...

Can you point to a single person making the point previously that even small amounts of uncertainty in the distribution of each variable in the Drake equation often implies a small or near-zero number of ETI even when the best mean point-estimate of the distribution for each variable, when multiplied together, predicts a large mean number of ETIs?

I don't understand. Your point ("even small amounts of uncertainty ... a large mean number of ETIs?") sounds just like a rephrasing of his ("We don't know the parameters well, it's within our margin of error that no one else is out there"). In particular, how could your statement be false while his be true?

His point, as suggested by the comments agreeing with him and the claims that it's 'obvious', is that the parameters could be small. The problem with that is the parameters look large. Adopting a distribution and calculating it out gives much broader predictive distributions. You can have all the parameters not be that small but small enough, combined with minimal uncertainty, that on many draws from the posteriors, you get underpopulated universes once all the uncertainty and probabilities are integrated. What he wants to take by theft from individual parameters, handwaving them away as being small and thus causing the paradox, can be obtained without any trickery for a wide range of parameter values and 'margin of error's simply by the nature of the pipeline process producing a wide range of final outputs. It's akin to confusing the confidence interval around a mean for the predictive interval.

I asked how his statement could be true while your statement could be false (which would show that even if his statement was granted then your statement could be new and non-obvious). You replied by claiming that his statement isn't justified while your statement is. This is a formalization of an intuitive argument, not a surprising dissolution of a paradox.

In other words, if other researchers had considered his statement and dismissed it without doing the sort of analysis being formally written up in this paper, then those dismissive researchers would have been making a mistake.

As I said elsewhere, I think these sorts of formalizations are really very helpful. Perhaps, given the sloppy thinking in this area, even more helpful than novel results. I generally think review articles are distillation is vastly undersupplied

Agreed. This is just picking parameters consistent with no detection of extraterrestrial civilizations. The point of the Fermi paradox is that it's a stretch to assume such parameters. It's not prediction about extraterrestrial civilizations collapsing or whatever. It's just an alternative to consider. And perhaps a warning about shouting at the Universe. Although it's probably too late to fret too much about that.

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. They've worked it formally and put it on a solid basis. Plus as we adjust our probability ranges in the future, the analysis can be re-run with new numbers easily and produce concrete, or at least, concretely-vague answers, instead of vaguely-vague intuitions.

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

I think you (and some others) are being dismissive of a good-faith attempt to formalize thinking of a problem with many unknowns. I can't access the paper itself, but commenter carry_bit posted a link to the slides, and the conclusion slide says:

The Fermi question is not a paradox: it just looks like one if one is overconfident in how well we know the Drake equation parameters.

• Doing a distribution model shows that even existing literature allows for a substantial probability of very little life, and a more cautious prior gives a significant probability for rare life.

• The Fermi observation makes the most uncertain priors move strongly, reinforcing the rare life guess and an early great filter.

• Getting even a little bit more information can update our belief state a lot!

I think their arguments deserve more consideration than what they are getting in this thread.

You should be able to access the paper. Arxiv doesn't require any logins or credentials or anything; just check the "download" section in the upper right. This should go straight to the PDF: https://arxiv.org/pdf/1806.02404 (Unless, you just mean you're on a device that can't render PDFs or something. It's a simple PDF, though, even a phone should be able to handle it.)

I'm on a large corporate network for a research organization, and I think they're rate-limiting us. All of the links give me an "Access Denied" message, with a referral to https://arxiv.org/denied.html. I can't even access https://arxiv.org/.

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

Of course there is enough data to pick the distributions of estimates given by various people. We have all the estimates given by people in hand.

You seem to be being dismissive without even remotely engaging with what is being discussed here.

Let's skip over the part where you fall back to the claim that the distribution of probabilities given by people isn't relevant to anything, because that's not important to the paper. The entire point is to examine the distribution of such probabilities, and compare it to the observed universe, and that's it. Nothing more.

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.

> I can't guarantee this is novel paper in general, but it's not something I've seen treated this formally before

Yea, I'd be very happy if they just said "here we make formal the possibility, considered since the paradox was first proposed, that there is enough uncertainty in each parameter that seeing zero ETI is perfectly compatible with expectations". That would have been a modest but useful contribution to the lit that would have informed further research. The issue I have is with claims that they are "dissolving" anything.

> And perhaps a warning about shouting at the Universe. Although it's probably too late to fret too much about that.

Any civilization sufficiently advanced to threaten us already has the capability to see we exist. For those with a large enough telescope, we have been emitting signs of life to the rest of the galaxy for billions of years.

It's only more recently that we have been showing signs of intelligent life (through radio waves and changes to our environment). These signs have not yet propagated throughout much of the galaxy yet, and there is a good argument we ought to get as advanced as possible as quickly as possible, so we can defend ourselves before others become aware of our intelligent existence.

> This is such an absurd claim to take as your own that it's literally on the wikipedia page!

Confirmed: https://en.wikipedia.org/wiki/Fermi_paradox#Extraterrestrial...

But it's posted in the pop-physics category. It doesn't seem inappropriate as a popular science article.

Thanks for pointing this out, it changes my perception of this article entirely.

The paper just says that Fermi estimation method is not applicable in this case. It does not say that there is no life, it says that is not the right way to estimate life existence. You can as well flip a coin, and then be amazed that aliens do not turn up when you guess heads right.

The most interesting option (danger: my dumbass opinions ahead) for why there's no other communicating species in radio range is whether there's a great filter right under our nose.

If we can ever prove that there's plenty of planets and plenty of abiogenesis and plenty of multicellular things out there that just don't know how to make radio waves, then either the leap to technology is exceedingly rare or we are in very big trouble very soon. I could see that keeping some people up at night.

Of course it could just be that, like us, other technological beings don't constantly broadcast super-directional radio transmissions at super-high power into random areas of space. We sent the Arecibo message a couple times for a few minutes, but it was really not enough to ever hope it got noticed by anyone out there. Even if space is bursting with intelligent life. Not even close. Cute project, though. Why do we expect more from others?

There was once a fairly mature plan, back in the 60s I believe, when nukes were still all the rage and people were discussing lots of exciting ways to use them for space exploration, wherein some physicist calculated how much power you'd need to make meaningful, intelligible radio contact a few stars over using an omnidirectional radio source. It involved setting off lots of nuclear bombs somewhere around Jupiter's orbit, in fact modulating the detonations and using the EMP as the signal. Those are the extreme methods needed get a signal out there up and over the noise of our own star, to defeat outrageous inverse square losses, to have it even barely intelligible at a very low baud rate a few light years away. Have we ever actually done that, even once? No.

So that should also tell you that nobody is listening to our old TV broadcasts and it's no surprise we aren't able to pick up anyone else's. No sane technological race is going to do an omnidirectional burst of communications meant for local use at such an enormous magnitude of power. It would be wasteful and destructive. Directed, focused transmissions only reach a billionth of the sky, so that has its own odds against it. SETI is a highly optimistic program considering the physics at work here.

The other argument for Fermi's paradox and why, if there are intelligent beings out there, we should know about it: If there's an advanced race even a couple million years ahead of us--just a blink of an eye in astronomical terms--they should have proliferated through the whole galaxy by now. We wouldn't be listening to their broadcasts, we would be them. Even discounting how unlikely it is that any race will ever be able to get to another star, this assumes that life (or Von Neumann machines) will spread and replicate endlessly, until they fill an extremely large space and convert an astronomically large amount of mass into themselves. We don't really see that with life we have on Earth. Most of our biome is still matter which is not life, and it's been here for billions of years. I don't understand the assumption that life will spread infinitely instead of staking out a reasonably large area that is barely manageable and then cull down, as life does here in our data set.

Even if there's a lot of technological species out there, and they're broadcasting with rational amounts of power, and they've expanded to cover rational amounts of space, it's still no surprise that we haven't found one yet. It's almost impossible to keep in mind just how big it all is. We also haven't been searching exhaustively or for a very long period of time. Would an alien SETI comparable to ours be able to detect our own transmissions? It's actually really unlikely.

"Most of our biome is still matter which is not life, and it's been here for billions of years."

Our planet is called Earth you know, which also means dirt. Because it seems to be covered in organic matter. If your perspective was correct, wouldn't we call the planet "Rock" or something?