Category: Fermi’s Paradox

Don’t Don’t Fear the Filter

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I.

On the occasion of the end of the old decade and the beginning of the new, Scott Alexander of Slate Star Codex, wrote a post titled What Intellectual Progress Did I Make in the 2010s. I am generally a great admirer of Alexander, in fact, though I don’t mention it often in this space I have been turning every one of his blog posts into an episode in a podcast feed since late 2017. In particular, I am impressed by his objectivity, his discernment, and dispassionate analysis. But in this particular post he said something which I take strong exception to:

In terms of x-risk: I started out this decade concerned about The Great Filter. After thinking about it more, I advised readers Don’t Fear The Filter. I think that advice was later proven right in Sandler, Drexler, and Ord’s paper on the Fermi Paradox, to the point where now people protest to me that nobody ever really believed it was a problem.

I am not only one of those who once believed it was a problem, I’m one who still believes it’s a problem. And in particular it’s a problem for rationalists and transhumanists, which are exactly the kind of people Alexander most often associates with and therefore most likely to be the people who now protest that nobody ever really believed it was a problem. But before we get too deep into things, it would probably be good to make sure people understand what we’re talking about.

Hopefully, most people reading this post are familiar with Fermi’s Paradox, but for those who aren’t, it’s the apparent paradox between the enormous number of stars and the enormous amount of time they’ve existed, and the lack of any evidence for civilizations, other than our own, arising among those billions of stars over those billions of years. Even if you were already familiar with the paradox you may not be familiar with the closely related idea of the Great Filter which is an attempt to imagine the mechanism behind the paradox, and in particular when that mechanism might take effect. 

Asking what prevented anyone else from getting as far, technologically, as we’ve gotten, or most likely a lot father is to speculate about the Great Filter. It can also take an inverted form, when someone asks what makes us special. But either way, the Great Filter is that thing which is either required for a detectable interstellar presence or which prevents it. And what everyone wants to know is whether this filter is in front of us or behind us. There are many reasons to think it might be ahead of us. But most people who consider the question hope that it’s behind us, that we have passed the filter. That we have, one way or another, defeated whatever it is which prevents life from developing and being detectable over interstellar distances.

Having ensured we’re on the same page we can return to Alexander’s original quote above, where he mentions two sources for his lack of concern. First his own post on the subject: “Don’t Fear the Filter”, and second the Sandler, Drexler, Ord paper on the paradox.

II.

Let’s start with his post. It consists of him listing four broad categories of modern risks which people hypothesis might represent the filter. Which would indicate both that the filter is ahead of us, and that we should be particularly concerned about the risk in question. Alexander then proceeds to demonstrate that these risks as unlikely to be the Great Filter. As I said, I’m a great admirer of Alexander, but he makes several mistakes in this post.

To begin with, he makes the very mild mistake of dismissing anything at all. Obviously this is eminently forgivable, he’s entitled to his opinion and he does justify that opinion, but given how limited our knowledge is in this domain, I think it’s a mistake to dismiss anything. To return to my last post, if someone had come to Montezuma in 1502 when he took the throne and told him that strangers had arrived from another world and that within 20 years he would be dead and his empire destroyed, and that in less than 100 years 95% of everyone in the world (his world) would be dead, he would have been dismissed as a madman, and yet that’s exactly what happened.

Second, his core justification for arguing that we shouldn’t fear the filter is that it has to be absolutely effective at preventing all civilizations (other than our own) from interstellar communication. He then proceeds to list four things which are often mentioned as being potential filters, but which don’t fulfill this criteria of comprehensiveness, because these four things are straightforward enough to ameliorate that some civilization should be able to do it even if ours ends up being unable to. This is a reasonable argument for dismissing these four items, but in order to decisively claim that we shouldn’t “fear the filter”, he should at least make some attempt to identify where the filter actually is, if it’s not one of the things he lists. To be charitable, he seems to be arguing that the filter is behind us. But if so you have to look pretty hard to find that argument in his post.

This takes me to my third point. It would be understandable if he made a strong argument for the filter being behind us, but really, to credibly banish all fear, even that isn’t enough. You would have to make a comprehensive argument, bringing up all possible candidates for a future filter, not merely the ones that are currently popular. It’s not enough to bring up a few x-risk candidates and then dismiss them for being surmountable. The best books on the subject, like Stephen Webb’s If the Universe Is Teeming with Aliens … WHERE IS EVERYBODY?: Seventy-Five Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life (which I talked about here) and Milan M. Ćirković’s The Great Silence: Science and Philosophy of Fermi’s Paradox (which I talked about here and my personal favorite book on the topic) all do this. Which takes me to my final point.

People like Ćirković and Webb are not unaware of the objections raised by Alexander. Both spend quite a bit of time on the idea that whatever is acting as the filter would have to be exceptionally comprehensive, and based on that and other factors they rate the plausibility of each of the proposed explanations. Webb does it as part of each of his 75 entries, while Ćirković provides a letter grade for each. How does he grade Alexander’s four examples?

  1. Nuclear War: Alexander actually includes all “garden variety” x-risks, but I’ll stick to nuclear war in the interests of space. Ćirković gives this a D.
  2. Unfriendly AI: Ćirković places this in category of all potential self-destructive technologies and gives the entire category a D+.
  3. Transcendence: Ćirković gives this a C-/F. I can’t immediately remember why he gave it two grades, nor did a quick scan of the text reveal anything. But even a C- is still a pretty bad grade.
  4. The Dark Forest (Exterminator aliens): Ćirković gives this a B+, his second highest rating out of all candidates. I should say I disagree with this rating (see here) for much the same reasons as Alexander.

With the exception of the last one, Ćirković has the same low opinion of these options as Alexander. And if we grant that Alexander is right and Ćirković is wrong on #4 which I’m happy to do since I agree with Alexander. Then the narrow point Alexander makes is entirely correct, everyone agrees that these four things are probably not the Great Filter, but that still leaves 32 other potential filters if we use Ćirković’s list, and north of 60 if we use Webb’s list. And yes, some of them are behind us (I’m too lazy to separate them out) but the point is that Alexander’s list is not even close to being exhaustive.

(Also, any technologically advanced civilization would probably have to deal with all these problems at the same time, i.e. if you can create nukes you’re probably close to creating an AI, or exhausting a single planet’s resources. Perhaps individually they should each get a D grade, but what about the combination of all of them?)

If I was being uncharitable I might accuse Alexander of weak-manning arguments for the paradox and the filter, but I actually don’t think he was doing that, rather my sense is that like many people with many subjects, despite his breadth of knowledge elsewhere, he doesn’t realize how broad and deep the Fermi’s Paradox discussion can get, or how many potential future filters there are which he has never considered.

III.

Most people would say that the strongest backing for Alexander’s claim is not his 2014 post, but rather the Sandler, Drexler, and Ord study (SDO paper).

(Full disclosure: In discussing the SDO paper I’m re-using some stuff from an earlier post I did at the time the study was released.)

To begin with, one of Alexander’s best known posts is titled Beware the Man of One Study, where he cautions against using a single study to reach a conclusion or make a point. But isn’t that exactly what he’s doing here? Now to be fair, in that post he’s mostly cautioning against cherry picking one study out of dozens to prove your point. Which is not the case here, mostly because there really is only this one study, but I think the warning stands. Also if you were going to stake a claim based on a single study the SDO paper is a particularly bad study to choose. This is not to say that the results are fraudulent, or that the authors made obvious mistakes, or that the study shouldn’t have been published, only that the study involves throwing together numerous estimates (guesses?) across a wide range of disciplines, where, in most cases direct measurement is impossible. 

The SDO paper doesn’t actually center on the paradox. It takes as its focus Drake’s equation, which will hopefully be familiar to readers of this blog. If not, basically Drake’s equation attempts to come up with a guess for how many detectable extraterrestrial civilizations there might be by determining how many planets might get through all the filters required to produce such a civilization (e.g. How many planets are there? What percentage have life? What percentage of that life is intelligent? etc.). Once you’ve filled in all of these values the equation spits out an expected value for the number of detectable civilizations, which generally turns out to be reasonably high, and yet there aren’t any, which then brings in the paradox.

The key innovation the SDO paper brings to the debate is to map out the probability distribution one gets from incorporating the best current estimates for every parameter in the equation, and pointing out that this distribution is very asymmetrical. We’re used to normal distributions (i.e. bell curves) in which the average and the most likely outcome are basically the same thing, but the distribution of potential outcomes when running numbers through Drake’s equation are ridiculously wide and on top of that not normally distributed which means, according to the study, the most probable situation is that we’re alone, even though the average number of expected civilizations is greater than one. Or to borrow the same analogy Alexander does:

Imagine we knew God flipped a coin. If it came up heads, He made 10 billion alien civilization. If it came up tails, He made none besides Earth. Using our one parameter Drake Equation, we determine that on average there should be 5 billion alien civilizations. Since we see zero, that’s quite the paradox, isn’t it?

No. In this case the mean is meaningless. It’s not at all surprising that we see zero alien civilizations, it just means the coin must have landed tails.

As I said, it’s an innovative study, and a great addition to the discussion, but I worry people are putting too much weight on it, because the paper does some interesting and revealing math and it looks like science, when, as Michael Crichton pointed out in a famous speech at Stanford, Drake’s equation is most definitely not science. (Or if you want this same point without climate change denial you could check out this recent post from friend of the blog Mark.) The SDO paper is a series of seven (the number of terms in Drake’s equation) very uncertain estimates, run through a monte carlo simulator, and I think there’s a non-trivial danger of garbage in garbage out. But at a minimum I don’t think the SDO paper should generate the level of certainty Alexander claims for it. 

If this is right – and we can debate exact parameter values forever, but it’s hard to argue with their point-estimate-vs-distribution-logic – then there’s no Fermi Paradox. It’s done, solved, kaput. Their title, “Dissolving The Fermi Paradox”, is a strong claim, but as far as I can tell they totally deserve it.

His dismissal of parameter values is particularly hard to understand. (Unless he thinks current estimate ranges will basically continue to hold forever.) The range of values determines the range of the distribution. Clearly there are distributions where the SDO paper’s conclusion no longer holds. All it would take to change it from “mostly likely alone”, to “there should be several civilizations” would be a significant improvement in any of the seven terms or a minor improvement in several. Which seems to be precisely what’s been happening.

IV.

From 1961 when Drake’s equation was first proposed, until the present day, our estimates of the various terms has gotten better, and as our uncertainty decreased it almost always pointed to life being more common.

One great example of this, is the current boom in exoplanet discovery. This has vastly reduced the uncertainty in the number of stars with planets. (Which is the second term in the equation.) And the number of planets which might support life (the third term). The question is, as uncertainty continues to be reduced in the future, in which direction will things head? Towards a higher estimate of detectable civilizations or towards a lower estimate? The answer, so far as I can tell, is that every time our uncertainty gets less it updates the estimate in favor of detectable civilizations being more common. There are at least three examples of this:

  1. The one I just mentioned. According to Wikipedia when Frank Drake first proposed his equation, his guess for the fraction of stars with planets was ½. After looking at the data from Kepler, our current estimate is basically that nearly all stars have planets. Our uncertainty decreased and it moved in the direction of extraterrestrial life and civilizations being more probable.
  2. The number of rocky planets, which relates to the term in the equation for the fraction of total planets which could sustain life. We used to think that rocky planets could only appear seven billion years or so into the lifetime of the universe. Now we know that they appeared much earlier. Once again our uncertainty decreased, and it did so in the direction of life and civilizations being more probable.
  3. The existence of extremophiles. We used to think that there was a fairly narrow band of conditions where life could exist, and then we found life in underwater thermal vents, in areas of extreme cold and dryness, in environments of high salinity, high acidity, high pressure, etc. etc. Yet another case where as we learned more, life became more probable, not less.

But beyond all of this, being alone in the galaxy/universe reverses one of the major trends in science. The trend towards de-emphasizing humanity’s place in creation.

In the beginning if you were the ruler of a vast empire you must have thought that you were the center of creation. Alexander the Great is said to have conquered the known world. I’m sure Julius Caesar couldn’t have imagined an empire greater than Rome, but I think Emperor Yuan of Han would have disagreed.

But surely, had they know each other, they could agreed that between the two of them they more or less ruled the whole world? I’m sure the people of the Americas, would have argued with that. But surely all of them together could agree that the planet on which they all lived was at the center of the creation. But then Copernicus comes along, and says, “Not so fast.” (And yes I know about Aristarchus of Samos.)

“Okay, we get it. The Earth revolves around the Sun, not the other way around. But at least we can take comfort in the fact that man is clearly different and better than the animals.”

“About that…” says Darwin

.

“Well at least our galaxy is unique…”

“I hate to keep bursting your bubble, but that’s not the case either,” chimes in Edwin Hubble.

At every step in the process when someone has thought that humanity was special in any way someone comes along and shows that they’re not. It happens often enough that they have a name for it, The Copernican Principle (after one of the biggest bubble poppers). Which, for our purposes, is interchangeable with the Mediocrity Principle. Together they say that there is nothing special about our place in the cosmos, or us, or the development of life. Stephen Hawking put it as follows:

The human race is just a chemical scum on a moderate-sized planet, orbiting around a very average star in the outer suburb of one among a hundred billion galaxies.

This is what scientists have believed, but if we are truly the only intelligent, technology using life form in the galaxy or more amazingly the visible universe, then suddenly we are very special indeed. 

V.

As I mentioned the SDO paper, despite its title, is only secondarily about Fermi’s Paradox. It’s actually entirely built around Drake’s Equation, which is one way of approaching the paradox, but one that has significant limitations. As Ćirković says, in The Great Silence:

In the SETI [Search for Extraterrestrial Intelligence] field, invocation of the Drake equation is nowadays largely an admission of failure. Not the failure to detect extraterrestrial signals—since it would be foolish to presuppose that the timescale for the search has any privileged range of values, especially with such meagre detection capacities—but of the failure to develop the real theoretical grounding for the search.

Ćirković goes on to complain that the equation is often used in a very unsophisticated fashion, and in reality it should be “explicated in terms of relevant probability distribution functions” and to be fair, that does appear to be what the SDO paper is attempting, whether they’re succeeding is a different matter. Ćirković seems to be suggesting a methodology significantly more complicated than that used by the study. But, this is far from the only problem with the equation. The biggest is that none of the terms accounts for interstellar travel by life and civilizations to planets beyond those where they arose in the first place. 

The idea of interstellar colonization by advanced civilizations is a staple of science fiction and easy enough to imagine, but most people have a more difficult time imagining that life itself might do the same. This idea is called panspermia, and from where I sit, it appears that the evidence for that is increasing as well. On the off chance that you’re unfamiliar with the term, panspermia is the idea that life, in its most basic form, started somewhere else and then arrived on Earth once things were already going. Of greater importance for us is the idea that if it could travel to Earth there’s a good chance it could travel anywhere (and everywhere). In fairness, there is some chance life started on say, Mars and travelled here, in which case maybe life isn’t “everywhere”. But if panspermia happened and it didn’t come from somewhere nearby, then that changes a lot.

Given the tenacity of life I’ve already mentioned above (see extremophiles) once it gets started, there’s good reason to believe that it would just keep going. This section is more speculative than the last section, but I don’t think we can rule out the idea, and it’s something Drake’s equation completely overlooks, and by extension, the SDO paper. That said, I’ll lay out some of the recent evidence and you can decide where it should fit in:

  1. Certain things double every so many years. The most famous example of this phenomenon is Moore’s Law, which says that the number of transistors on an integrated circuit doubles every two years. A while back some scientists wanted to see if biological complexity followed the same pattern. It did, doubling every 376 million years. With forms of life at the various epochs fitting neatly onto the graph. The really surprising thing was that if you extrapolate back to zero biological complexity you end up at a point ten billion years ago. Well before the Earth was even around (or Mars for that matter). Leaving Panspermia as the only option. Now the authors confess this is more of a “thought exercise” than hard science, but that puts it in a very similar category to Drake’s equation. And there’s an argument to be made that the data for the doubling argument is better.
  2. There’s a significant amount of material travelling between planets and even between star systems. I mentioned this in a previous post, but to remind you. Some scientists decided to run the numbers, on the impact 65 million ago that wiped out the dinosaurs. And they discovered that a significant amount of the material ejected would have ended elsewhere in the Solar System and even elsewhere in the galaxy. Their simulation showed that around 100 million rocks would have made it to Europa (a promising candidate for life) and that around a 1000 rocks would have made it to a potentially habitable planet in a nearby star system (Gliese 581). Now none of this is to say that any life would have survived on those rocks, rather the point that jumps out to me is how much material is being exchanged across those distances.
  3. Finally, and I put this last because it might seem striking only to me. Apparently the very first animal (as in the biological kingdom Animalia) had 55% of the DNA that humans have. They ascribe this to an “evolutionary burst of new genes”, but for me that looks an awful lot like support of the first point in this list. The idea that life has been churning along for a lot longer than we think, if the first animal had 55% of our DNA already half a billion years ago.

Now, of course, even if panspermia is happening, that doesn’t necessarily make the SDO paper wrong. You could have a situation where the filter is not life getting started in the first place, the filter is between any life and intelligent life. It could be that some kind of basic life is very common, but intelligence never evolves. Though before I move on to the next subject, in my opinion that doesn’t seem likely. You can imagine that if life itself has a hard time getting started, in any form, that out of the handful of planets with life, that only one develops intelligence. But if panspermia is happening, and you basically have life on every planet in the habitable zone, a number estimated at between 10 and 40 billion, then the idea that out of those billions of instances of life that somehow intelligence only arose this one time seems a lot less believable. (And yes I know about things like the difficulty of the prokaryote-eukaryote transition.)

VI.

The final reason I have for being skeptical of the conclusion of the SDO paper is that as far as I can tell they give zero weight to the fact that we do have one example of a planet with intelligent life, and capable of interstellar communication: Earth. In fact if I’m reading things correctly they appear to give a pretty low probability that even we should exist. My sense is that when it comes to Fermi’s paradox this is the one piece of evidence no one knows exactly how to handle. On the one hand, as I pointed out, the history of science has been inextricably linked to the Copernican principle. The idea that Earth and humanity are not unique, and yet on this one point the SDO paper make the claim that we are entirely unique, that there is probably not another example of detectable life anywhere in our galaxy of 250 billion stars. 

You might think there is no, “On the other hand”, but there is. It’s called the anthropic principle, which says there’s nothing remarkable about our uniqueness, because only our uniqueness allows it to be remarked upon. Or in other words, conscious life will only be found in places where conditions allow it to exist, therefore when we look around and find that things are set up in just the right way for us to exist, it couldn’t be any other way because if they weren’t set up in just the right way no one would be around to do the looking. There’s a lot that could be said about the anthropic principle, and this post is already quite long. But there are three points I’d like to bring up:

  1. It is logically true, but logically true in the sense that a tautology is logically true. It basically amounts to saying I’m here because I’m here, or if things were different, they’d be different. Which is fine as far as it goes, but it discourages further exploration and a deeper understanding of why we’re here, or why things are different, rather than encouraging it.
  2. To be fair, it does get used, and by some pretty big names. Stephen Hawking included it in his book A Brief History of Time, but Hawkings and others generally use it as an answer to the question of why all the physical constants seemed fine tuned for life. To which people reply there could be an infinite number of universes, so we just happen to be in the one fine tuned for life. Okay fine, but there’s no evidence that the physical constants we experience don’t apply to the rest of the galaxy. The only way it makes sense for Fermi’s Paradox is to argue that our Solar System, or the Earth is fine-tuned for intelligent life. Or that we were just insanely, ridiculously lucky. 
  3. It’s an argument from lack of imagination. In other words, critics of the paradox assert that we are alone because there has not been any evidence to the contrary. But it is entirely possible that we have just not looked hard enough, that our investigation has not been thorough enough. On questioning they will of course admit this possibility, but it is not their preferred explanation. Their preferred explanation is that we’re alone and the filter is behind us, and they will provide a host of possibilities for what that filter might be, but we really know very little about any of them. 

As you might have gathered, I’m not a very big fan of the anthropic principle. I think it’s a cop out. Perhaps you don’t, perhaps, on top of that, you think the idea of panspermia is ridiculous. Fair enough, my project is not to convince you that the anthropic principle is fallacious, or that panspermia definitely happened. My project is merely to illustrate that it’s premature to say that the Great Filter is behind us, that the Fermi Paradox is “solved” or “kaput”. And all that requires is that any one of the foregoing pieces of evidence I’ve assembled ends up being persuasive. 

Beyond all this there is the question we must continually revisit, in which direction is the error worse? If the Great Filter is actually behind us but out of an abundance of caution we spend more effort than we would have otherwise on x-risks, that’s almost certainly a good thing. In particular since there are plenty of x-risks which could end our civilization which are nevertheless not the Great Filter. Accordingly, any additional effort is almost certainly a good thing. On the other hand, if the Great Filter is ahead of us, then the worst thing we could do is dismiss the possibility entirely, and dismissing it on the basis of a single study might be the saddest thing of all.


Much like with Fermi’s Paradox, everyone reading this assumes that if they’re intelligent enough to appreciate this post, then there must be other readers out there somewhere who share the same intelligent appreciation, but what if there’s not, what if you’re the only one? Given that this might be the case wouldn’t it be super important for you, as the only person with that degree of intelligence to donate


The Secular Answer To Fermi’s Paradox

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Having explored at some length in our last post the idea that Fermi’s Paradox may offer strong support for the existence of God.  As well as the idea that assumptions made about extraterrestrial communication line up better than might be expected with the process of prayer. I want to flip the coin and look at what the conventional wisdom is as far as the Paradox. For my examination I will be mostly drawing from If the Universe Is Teeming with Aliens … WHERE IS EVERYBODY?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life, by Stephen Webb. There has obviously been quite a bit written about the paradox, but this appears to be one of the only (if not the only) book length treatments. My discussion will use the first edition of the book, which has 50 potential explanations for the Paradox. The second edition, which I have yet to acquire has 75 potential explanations. I cannot speak definitively about the second edition, but of the 50 potential explanations in the first none resemble the explanation I offered in my last post. But otherwise it is admirably comprehensive.

Webb breaks extraterrestrials into three broad categories:

  1. They are here.
  2. They exist but have not communicated with us.
  3. They don’t exist.

The first possibility is broader than the initial title would suggest. It essentially encompasses all scenarios under which aliens exist, and are aware of us. These explanations range from the humorous (They are here and they call themselves Hungarians) to explanations for why, if they exist, they might choose to hide from us. The classic example of this thinking is the Prime Directive from Star Trek, the principle that the federation will not interfere with any less advanced civilizations.

Interestingly enough the final explanation in the “They are Here” section is titled “God Exists”. From the title, at least, it sounded like it must be very similar to my own thinking. It wasn’t. Webb spends a couple of paragraphs talking about some vague theological issues, but then spends the rest of the section (four more pages) examining the idea that there seems to be no good reason for the constants of the Universe to have the values they do (for example the strength of the weak nuclear force or the mass of an electron.) From there he goes on to discuss a theory of universe evolution under which new universes might be created by black holes so universes would “evolve” to maximize black hole production. If the physical constants which lead to the creation of black holes are similar to the constants necessary for the emergence of life you might end up with the second condition being a byproduct of the first.

The second possibility, that they exist but have not communicated with us, generally boils down to the idea that on top of the enormous number of stars and the enormous amount of time that has passed, which argue in favor of alien life, that there are other enormous numbers: the distance between habitable planets (less now than a couple of weeks ago); the number of ways language and communication could develop; the different types of intelligent life; and so forth, which argue against alien communication. This could mean that it’s just too far, or that they are communicating with us and we don’t understand, or in one of the more off-beat explanations, perhaps most worlds have skies perpetually shrouded in clouds. In which case, would they ever even develop astronomy, or even a full Newtonian understanding of the Universe?  

The final possibility is that there is some kind of filter which works against intelligent extraterrestrial life. Some process which keeps life from starting at all, from reaching sufficient complexity, from developing consciousness, from lasting long enough to spread, or from accomplishing any of the thousands of steps required to have a truly interstellar civilization. As you can imagine, such a filter might be behind us, or it might be in front of us. Examples which have been offered for filters we have already passed, have included: the difficulty of moving from prokaryotes to eukaryotes, galactic catastrophes like supernovas, getting life started in the first place, and even plate tectonics.  

Examples which have been offered for filters yet to come include: blowing ourselves up with nukes, losing ourselves in virtual reality, civilizational collapse, or of course galactic or solar catastrophes yet to come. Another explanation is that aliens do exist, but they’re aggressive and warlike and no one wants to risk initiating communication (or what’s termed Active SETI) because they’re all afraid they’ll be discovered and destroyed.

This is of course one of the things that makes Fermi’s Paradox so fascinating, the number of possible explanations is huge and those explanations can tie into anything (from the Runaway Consumerism to having a particularly large Moon.)

I said that Webb’s book offered up 50 explanations for the paradox. That’s not entirely true. He actually offers up 49 explanations and then for the 50th he offers his own explanation. He mentions in one of the introductory sections that the 50th explanation will be his explanation for the paradox, and while reading the book I was intensely curious about what his explanation would be. And if, for whatever reason you were thinking of reading the book (which I recommend only if you are REALLY interested in the paradox) and you don’t want to be spoiled you should stop reading now…

Webb’s final solution titled “The Fermi Paradox Resolved…” is not unique, it’s not some new take on things or an explanation that hasn’t been offered already, it’s the combination several explanations. Having gone through 49 possible explanations for the paradox Webb’s answer is that we are alone. This is an interesting conclusion. And I think he reaches it somewhat reluctantly, but it carries an enormous number of consequences, not all of which he’s willing to grapple with. But before we get to that let’s examine how he arrives at his conclusion.

In a similar fashion to how Fermi and Drake arrived at their numbers, Webb comes up with is own filter for determining how many intelligent civilizations there should be. All of his filters come from the previous 49 explanations of the paradox already laid out in his book. And in a fashion similar to Drake, he starts with the number of stars in the galaxy. He then multiplies that by the average number of planets per star. This gives him a number of 10^12 or one trillion potential planets. Starting from there he begins to filter planets out. His filtering process is somewhat involved and scholarly, but it’s interesting enough that I’d like to walk through it. He goes through seven steps (actually 8, but one of his steps doesn’t actually filter anything, so we’ll skip it.)

Step 1- Eliminate any planets not in the galactic habitable zone. Most people are familiar with the solar habitable zone, (discussed more in step 3). This is the same thing on the galactic scale, and mostly has to do with the frequency of large scale galactic catastrophes. If you’re too close to the center of the galaxy, then the density of stars is such that galactic catastrophes would be frequent, potentially too frequent for life to ever establish a foothold. Consequently only stars out on the rim of the galaxy would accident free enough for life to develop, and this region is the galactic habitable zone. Webb uses an estimate of 20% of stars being in this zone so that takes us down to 200 billion planets.

Step 2- Eliminate any planets which don’t orbit sun-like stars. Bigger stars burn too fast and smaller stars don’t give off enough energy. Only 5% of stars are sun-like (G-Type) which leaves us with 10 billion planets.

Step 3- Eliminate any planets which aren’t in the continuously habitable zone (CHZ) of the star. This means, not only do they currently have to be at a distance from the star where water is liquid, but they have to have always been at that distance. He puts this number at 0.1% of planets. Which frankly seems extremely conservative particularly in light of the data we’re getting from Kepler which is biased against Earth-sized planets. To be fair to Webb part of the low estimate comes from the idea that the Sun was much fainter in the past. That filter takes us to 10 million planets.

Step 4- Eliminate any planet in the CHZ on which life doesn’t actually emerge. After saying that he considers life to be a probable occurrence for planets in the CHZ he, somewhat unexpectedly, goes on to say that it would happen on only 5% of them. Which takes us to half a million.

Step 5- Eliminate any planet where life gets wiped out by a supernova or some similar solar or galactic catastrophe. Here he’s fairly optimistic and thinks that only about 20% of life would be eliminated in this fashion. I think on this step, contrary to all the other steps he is too optimistic, that possibly far more than 20% could be wiped out by something like a supernova or some giant collision. Though we have also eliminated the planets most prone to this in Step 1. In any event this takes him to 400,000.

Step 6- Eliminate any planet where life doesn’t ever get to be multicellular. Conveniently he places the odds at life making the jump from single celled to multi celled at 1 in 40 which works out nicely to give us 10,000 planets with multicellular life.

Step 7- Eliminate any planets where life doesn’t produce an intelligent, tool-using, mathematical species capable of developing technology. He thinks the odds of this happening are least 1 in 10,000 (0.01%) and possibly much greater which means that there is only one of those civilizations, us. We are alone.

At first glance the whole process seems scientific, but similar to the Drake equation Webb has very little evidence for any of his estimates. The late Michael Crichton of Jurassic Park and Andromeda Strain fame once gave a talk about the Drake Equation at Caltech. His purpose was to take a shot at global warming, and perhaps you’ll dismiss it on that grounds, but his point was nevertheless valid:

This serious-looking equation gave SETI a serious footing as a legitimate intellectual inquiry. The problem, of course, is that none of the terms can be known, and most cannot even be estimated. The only way to work the equation is to fill in with guesses. And guesses-just so we’re clear-are merely expressions of prejudice.

Nor can there be “informed guesses.” If you need to state how many planets with life choose to communicate, there is simply no way to make an informed guess. It’s simply prejudice.

As a result, the Drake equation can have any value from “billions and billions” to zero. An expression that can mean anything means nothing. Speaking precisely, the Drake equation is literally meaningless, and has nothing to do with science. I take the hard view that science involves the creation of testable hypotheses. The Drake equation cannot be tested and therefore SETI is not science. SETI is unquestionably a religion.

His point about SETI being a religion is particularly telling for the purposes of this blog and our discussion. As is his point that the guesses are an expression of prejudice. In the case above it’s obvious that Webb already has a final answer in mind before he started plugging in his guesses, it didn’t just happen to come out with one to his amazement and surprise, he arranged his guesses so that it would come out as one.

Think about that for a second, you start off with one trillion, and in the end you’ve created a filter that leaves just one planet left out of the one trillion you started with?  Not zero, not a million? Imagine that you were going to create a set of seven filters which when applied to 7+ billion humans left you with one and only one person, and that you could only use natural criteria, like weight and height, not artificial filters like a social security number or the name of the town they were born in. It would be impossible, and recall that Webb starts with one trillion planets, not seven billion, so he’s already dealing with potential set over 100 times as large.

But let us for the moment assume that he’s correct. That in all the galaxy we are the only intelligent, technological life. As I already mentioned, the consequences of that are far-reaching and extreme.

First it reverses one of the major trends in science. The trend towards de-emphasizing humanity’s place in the universe.

In the beginning if you were the ruler of a vast empire you must have thought that you were the center of creation. Alexander the Great is said to have conquered the known world. I’m sure Julius Caesar couldn’t have imagined an empire greater than Rome, but I think Emperor Yuan of Han would have disagreed.

But surely, had they know each other, they could agreed that between the two of them they more or less ruled the whole world? I’m sure the people of Americas, who were entirely unknown to them, would have argued with that. But surely all of them could agree that the planet on which they all lived was at the center of the universe. But then Copernicus comes along, and says, “Not so fast.” (And yes I know about Aristarchus of Samos.)

“Okay, we get it. The Earth revolves around the Sun, not the other way around. But at least we can take comfort in the fact that man is clearly different and better than the animals.”

“About that…” says Darwin.

“Well at least our galaxy is unique…”

“I hate to keep bursting your bubble, but that’s not the case either,” chimes in Edwin Hubble.

At every step in the process when someone has thought that humanity was special in anyway someone comes along and shows that they’re not. It happened often enough that now they have a name for it, The Copernican Principle (after one of the biggest bubble poppers). Which, for our purposes, is interchangeable with the Mediocrity Principle. Together they say that there is nothing special about our place in the cosmos, or us, or the development of life. Stephen Hawking put it as follows:

The human race is just a chemical scum on a moderate-sized planet, orbiting around a very average star in the outer suburb of one among a hundred billion galaxies.

This is what scientist have believed, but if we are truly the only intelligent, technology using life form in the galaxy, then suddenly we are very special indeed. Which, as you’ll recall, is what religion has been arguing all along, and it is primarily against religion that these various attacks at uniqueness have been leveled.

Now obviously it’s not impossible for the Copernican principle to be wrong, but you can still imagine that it presents a problem for scientists to explain. Particularly for scientists who would rather not give any ammunition to the unbelievers. In other words, for militant atheists, the idea that we might be unique and special, that the universe and the galaxy and the solar system might have been designed for us, is deeply troubling. And if you talk to any of them who are knowledgeable about this issue, they have a response ready, the Anthropic Principle.

The Anthropic Principle is complicated enough that it almost certainly deserves it’s own post, particularly as we are already 2500+ words into this post, but in short what it says is that there’s nothing remarkable about our uniqueness, because only our uniqueness allows it to be remarked upon.

To expand on that a little bit. Conscious life will only be found in places where conditions allow it to exist, therefore when we look around and find that things are set up in just the right way for us to exist, it couldn’t be any other way because if they weren’t set up in just the right way no one would be around to do the looking.

As I said the subject is deep enough that it will probably eventually get it’s own post (though not next week I’m feeling a hankering for something different.) But I will end with four points about the anthropic principle to chew on:

1- It’s logically true, but logically true in the sense that a tautology is logically true. It basically amounts to saying I’m here because I’m here, or if things were different, they’d be different. Which is fine as far as it goes, but it discourages further exploration and a deeper understanding rather than encouraging it.

2- It’s generally used as an answer to the question of why all the physical constants seemed fine tuned for life. To which people reply there could be an infinite number of universes, so we just happen to be in the one fine tuned for life. Okay fine, but is there any evidence that the physical constants we experience don’t apply to the rest of the galaxy? Because that’s what we’re talking about when we talk about Fermi’s Paradox. In fact we don’t even have any evidence that they are different anywhere in the visible universe of the 100 billion additional galaxies. In other words if the Earth is fine-tuned for life as far as physical constants, so is the rest of the galaxy, at a minimum.

3- It’s an argument from lack of imagination. Or in other words Webb asserts that we are alone because there has not been any evidence to the contrary. It is entirely possible that we have just not looked hard enough. Webb admits this possibility of course, but it is not his preferred explanation, which is that we’re alone, because of the factors which I mentioned above, but all of those factors could just be a lack of imagination. Imagining how life could develop in the center of the galaxy, how life could develop outside of the CHZ (say Europa) or, especially, imagining how we might already be in contact with extraterrestrials and just call it prayer.

4- It’s not science. Just as Crichton (and others) argue that SETI is a religion, so is the anthropic principle. In this particular religion it’s easier to believe that we’re alone and use the anthropic principle as justification then to think that we’re not alone and that God exists. It’s the religion of, humanism, especially the belief that there is nothing beyond the limits of rationality and science.

When I said the consequences are far-reaching and extreme, this is what I meant. If we are truly alone, if we are the lone intelligence in the entire observable universe then that puts us in a position of awful responsibility, and takes us back to the premise of the blog. My assertion is that the harvest is past, the summer is ended, and we are not saved. If you assert that humanity is alone, that we are all there is, then what you’re saying is:

The harvest is past, the summer is ended, and we HAVE to be saved.


Fermi’s Paradox As a Proof of the Existence of God

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It all began one day sometime in 1950 at the Los Alamos National Laboratory. Enrico Fermi and some other scientists were discussing UFOs over lunch. It was the dawn of the atomic age (as they all well knew, working at Los Alamos) and anything seemed possible. Consequently their conversation covered all manner of speculative topics, including the potential for FTL travel. In the midst of their discussion, and seemingly out of nowhere, Fermi exclaimed, “Where are they?” The conversation had been so wide ranging, that it took the other scientists a moment to understand that he was talking about extraterrestrials. But in that moment the paradox which bears his name was born.

It was immediately apparent that Fermi’s question had touched on something deep. As the story goes Fermi went back to his office and ran some numbers (these calculations apparently pre-date the Drake Equation) and confirmed what he had already suspected, that even using incredibly modest assumptions, we should have been visited by extraterrestrials long ago and many times over. Instinctively Fermi and the other scientists recognized that the question touched on a deep paradox, which is why this question, out of all the questions ever asked while eating lunch, have survived to the present day.

I mentioned the Drake Equation, and it’s closely tied to Fermi’s Paradox, and it might be worth taking a brief detour into the question of what the Drake Equation is. One day in 1961 Frank Drake was preparing for a meeting on the search for extraterrestrial intelligence, and, according to his recollection, the equation came about during that preparation:

As I planned the meeting, I realized a few day[s] ahead of time we needed an agenda. And so I wrote down all the things you needed to know to predict how hard it’s going to be to detect extraterrestrial life. And looking at them it became pretty evident that if you multiplied all these together, you got a number, N, which is the number of detectable civilizations in our galaxy.

Drake’s equation essentially acts as a series of filters. (The concept of a filter will be very important in discussing Fermi’s Paradox.) You begin with the number of stars (technically the rate of star formation.) You then filter out any stars without planets. From there you filter out any planets which don’t have life, and then filter out that life which isn’t intelligent, and finally you filter out any life which is incapable of communicating on an interstellar scale. After filtering out all the possible stars and planets and life forms that aren’t communicating with us, you arrive at a number of, as Drake said, “detectable civilizations in our galaxy.”

What Fermi’s numbers and later Drake’s showed was that the first number, the number of stars, is so massive, (100 billion in the Milky Way) that even if you’re pretty conservative with your filtering you still end up with a big number. And even if you are very pessimistic with your estimates, and the number of expected civilizations ends up being small, another large number, the age of the galaxy, means that even if there only ended up being one star-faring civilization, they would have had plenty of time to spread out across the entire galaxy under almost any conceivable scenario.

The Drake Equation article on Wikipedia is fascinating, as is the article on Fermi’s Paradox, and I have borrowed heavily from both. In fact, rather than trying to restate everything I would just suggest that you read those articles. What I’m more interested in is viewing Fermi’s paradox through the lens of LDS Doctrine and LDS Cosmology. In the process, I don’t guarantee that we won’t end up fairly far afield, though I don’t imagine we will arrive anywhere too controversial.

LDS beliefs aside, from a broadly religious perspective it can only be viewed as fortunate that we haven’t been visited by extraterrestrials, or at least extraterrestrials of the sort envisioned by most science fiction. I don’t have the required background to speculate on the impact of such a visit on the eastern religions, but it could only be a huge blow to all the Abrahamic religions if aliens shows up and their belief system didn’t incorporate the idea of a single omniscient deity. It would therefore follow that Fermi’s Paradox works in favor of religion. In fact I would go so far as to say that Fermi’s Paradox is in fact a strong argument in favor of God generally, but, I hope to show that it’s even a stronger argument in favor of the specifically LDS conception of God.

The LDS conception of God is, as far as I know, unique among the religions. We’re basically in a category by ourselves when it comes the way extraterrestrials fit into our conception of God. To take just one example, directly from the scriptures:

And thus there shall be the reckoning of the time of one planet above another, until thou come nigh unto Kolob, which Kolob is after the reckoning of the Lord’s time; which Kolob is set nigh unto the throne of God, to govern all those planets which belong to the same order as that upon which thou standest.

Abraham 3:9

Obviously one can get pretty deep in the weeds when you start talking about Kolob and the more esoteric aspects of LDS cosmology, so I’ll try to keep that sort of speculation to a minimum. Even so, I don’t think one has to engage in much speculation to say that Mormons believe that God is an extraterrestrial, using the broadest definition of that term. Which, then means, if we follow that thought to it’s logical conclusion, that Mormons have the answer to Fermi’s Paradox. Fermi’s numbers suggested to him that we should have been visited by extraterrestrials long ago and many times. Well if God is an extraterrestrial then we have. There is no paradox. Additionally this would explain why no other extraterrestrials from visiting us (if there are other extraterrestrials in any meaningful sense in this scenario.)

On it’s face this argument seems perfectly reasonable to me, but I guess for most people it seems crazy, or impossible, or somehow unthinkable, because in all the time I’ve been interested in the paradox I don’t believe I’ve ever seen someone make this argument. (Though if past experience is anything to go by five minutes after I post this I’ll find someone making this exact argument.) I’ve have seen people come close. Interestingly one of the people who came the closest is Michael Shermer, a noted religious skeptic (he’s the founder of the Skeptics Society and Editor in Chief of Skeptic Magazine) In his answer to one of the Edge Questions of the Year he up the following:

Is God nothing more than a sufficiently advanced extra-terrestrial intelligence?

As you can see he get’s really close, but he never draws the connection between this question and the paradox, or makes the leap that I’m going to make which is to say that Fermi’s Paradox could be considered proof of God’s existence. I use proof in the sense of something which helps to establish the truth, not something which is ironclad and irrefutable. This proof would go something like this:

  1. Because of the huge number of stars and planets, it is inconceivable that we are the only intelligent life.
  2. Because of the huge amounts of time involved it is inconceivable that other intelligent life hasn’t spread through the galaxy and visited Earth.
  3. Because of the inevitable gigantic technological disparity which would exist between us and any spacefaring extraterrestrials they would appear to us as gods.
  4. Therefore the simplest explanation is that the being we refer to as God exists and fulfills all of the above criteria.

I feel like we should give this proof a name. Fermi’s Paradox’s indirect Proof for the Existence of God, seems too long, maybe Proof by Extraterrestrial Exclusion? In any event if someone out there thinks they see any big holes in this line of reasoning I’d welcome the chance to hear them. But I would argue that not only are there no holes in this line of thinking, but that most of the explanations which are offered for the paradox provide indirect support for this explanation.

I just got done watching The Big Short, which covers the housing crisis and the few people who were betting it would happen, and one of the main worries of the people in the movie was that they were overlooking something. That they had missed some key piece of information. If no one else was betting against the housing market maybe everyone knew something that they didn’t. They weren’t missing anything, but they were right to be skeptical, and at this point I should engage in similar skepticism. If no one has come up with this same line of thinking, am I missing something?

To continue with the comparison to the Big Short, a large part of the blindness which afflicted the people who were involved in the housing crisis was the assumption that you would never have a simultaneous nationwide decline in housing prices, in large part because it hadn’t ever happened before. I think a similar blindness affects the people thinking about Fermi’s Paradox. When people imagine aliens they mostly imagine a sort of ray-gun-flying-saucer sort of thing. Or they imagine something so inhuman that we might not even recognize it as life. Imagining that our contact with aliens might take the form of prayer is both too mundane and too fantastic. But to offer up an adaptation to Clarke’s Third Law (and I am not the first to suggest this modification):

Any sufficiently advanced technology is indistinguishable from a miracle.

Of course as all “educated” people know there aren’t any miracles, consequently when people involved in SETI look for signs of alien life they look for signals in the electromagnetic spectrum. Radio waves, or possibly lasers. And when they think of aliens visiting they think of something similar to Independence Day. But what should we be expecting if we really approach things without preconception or bias? (And by no means am I claiming that I am free from bias, only that I have a completely different set of biases.)

The first thing we should expect if we give any credence to Fermi is that they should already be here. This is obviously not what most people think. In fact most people have a bias towards expecting them to show up in the near future. A bias which got it’s start at the dawn of the age of science fiction with HG Wells and War of the Worlds (and almost certainly earlier than that, but Wells is probably the first author most people are aware of.) A bias which continues through to the present day with movies like the aforementioned Independence Day and the soon to be released Arrival.

But of course the chances that, in the 4.543 billion years of the Earth’s existence that aliens will pick next 50 to arrive are 0.00000001%. Aliens have either already visited or they never will. Communication would appear to be different than visiting, but not really. Think about it, if incredibly advanced aliens are out there then either they want to talk to us or they don’t. If they do want to talk to us then we should assume that, given that they’re thousands if not millions of years ahead of us in technology that they should have figured out a way to do it. Accordingly even if we restrict it to communication, I would once again say that there’s a strong bias towards it already happening, or never happening. Of course I’ve completely breezed past the idea that they’re waiting for something to happen before they talk to us. But that is an interesting enough topic that it deserves it’s own post. The point is, outside of some fringe theories about pyramids and Mayans the only current candidate for extraterrestrial communication is prayer.

I understand this will strike many people as an entirely ludicrous idea. But why? On what basis do they rule out this idea? I understand I may be accused of constructing a strawman, but since I haven’t seen this theory in print, let alone any objections to it, I don’t have any actual objections to answer, so we’ll have to imagine some. Still I think these won’t be too far from the mark.

Objection 1: Prayer is scientifically impossible.

Honestly I hope they’re smarter than this, and that this isn’t one of the objections, but I could certainly imagine that it would be. Everyone agrees that any potential aliens (LDS doctrine or no) would be at least thousands if not millions of years ahead of us technologically. How do we know, at our level of development what is or isn’t possible? I could trot out a list of everything we thought was impossible scant decades before it became commonplace. How can anyone have any confidence about predicting what is and isn’t possible with thousands, if not millions of years of additional progress?

Objection 2: Prayer is not the way aliens would contact us.

For people raised on the biases I already mentioned, when they imagine alien contact they imagine a single flying saucer landing in Washington DC or a scientist working late at night at some radio observatory. What they do not imagine is communication with single individuals that appears unreliable at best, mostly involves people asking for, or expressing gratitude for mundane things and is responded to with vague feelings of peace and the occasional (unconfirmable) vocalization. But why couldn’t it be? Once again it’s dangerous to make any assumptions about what extraterrestrials can and can’t do or would or wouldn’t do. To return to the Big Short, it opens with a quote by Mark Twain:

It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so.

In future posts I’ll get more into why prayer may be precisely the way that an advanced race of beings may want to talk to us, even if it were unmoored from its religious origins.

Objection 3: Prayer is inexplicably selective.  

Similar to the last objection, but this gets more into the fact that even if prayers are answered there a certainly cases where one set of prayers are answered while another are not. Non-mormon’s might also wonder why extraterrestrials would select 15 men to receive the best communication of all. Are we to imagine that aliens are Christian? (Why not?)

I’m sure there are other objections, but for the moment let’s stop with that last one, because I think the answers are similar, and this point it may be best to turn to an examination of what we, as humans, do in a similar situation.

There are in the world, many tribes which have no significant contact with global civilization. And it’s instructive to examine how we have chosen to deal with them, but also to examine more broadly what is and isn’t acceptable behavior towards them.

The first thing that we obviously don’t do, and that no one has suggested doing, is giving them a huge dump of technology. Whether that would be, in the worst case, a bunch of guns and ammo, or in the most innocuous case a set of encyclopedias. At the moment, what we mostly do is leave them alone. Though in the not too distant past we would contact them, and while this risks getting into an argument on how best to deal with indigenous people and colonialism, etc. such contact actually was largely religious in nature. The first people to show up when a new people were found were missionaries. And what did they try to do? Give them instruction in morality, build schools, and convert them to Christianity.

Interestingly I can’t think of any science fiction novel where the aliens set up schools, or educated humans in the dominant galactic religion (though Childhood’s End is sort of in that vein.) I think this is largely because people expect religion to disappear at a certain point in a civilization’s development. (I know the Hyperion Cantos keeps religion around, but his treatment of Christianity is pretty appalling.) I’m not claiming that a book written along those lines isn’t out there, but I know of no well known book written along that premise. What we mostly see are mysterious communications, or ships showing up with unclear intentions. There are of course war-like aliens, and those stories map well with the way civilization has dealt with more primitive tribes, but if there are aliens and they’re bent on war then we’re already screwed.

Let’s instead turn towards looking at how the objections to prayer might look if we applied them to contact with previously uncontacted people. The first objection was that prayer wasn’t scientific. I imagine that there are numerous ways we could use to contact these tribes which would seem equally miraculous as prayer seems to us, and remember that they’re only a few thousand years behind us in technology. We could be dealing with aliens that are millions of years ahead of us.

The second objection is that prayer isn’t how aliens would contact us. Okay, now take that thought and for a moment imagine that you’re an anthropologist studying an uncontacted tribe. Imagine that any individual in this tribe could send you a message, which would be instantly translated into your native language, and the message would describe in a detail not even available in a written journal the person’s deepest concerns, and the whole of their inner life? Yes there would obviously be privacy concerns, but for the moment put that aside (or you could assume that the anthropologist is maximally benevolent.) Wouldn’t that be the ideal way to allow that tribe to make contact? I think so. Perhaps you disagree. But I would think that you could at least see where such a system might have some significant advantages.

The final objection is that prayer is selective. Well so are we. You could certainly imagine that you might decide to contact one group of the previously uncontacted people without deciding to open the floodgates and contact all of them. You might do this because this particular group was in danger, or if they had developed a certain level of technology, or if they asked for help, or if you were experimenting with a new method of making contact. There are all manner of reasons why you might leave one group alone while making contact with another.

My point is not that prayer is so obviously alien communication as to preclude any other possible explanation, anymore than I am arguing that Fermi’s Paradox is obviously proof of God, but given how little we actually know, and given the assumptions that we can safely make, it fits at least as well as any other explanation and in some ways even better.