Fermi's Paradox, the tapeworm-and-anus versus

Fermi's Paradox speculates that the fact that our civilization has not yet encountered evidence of alien civilization implies that such life must not exist. In "Tapeworm Logic," Charlie Stross brilliantly skewers this by looking at the version of Fermi's Paradox that a tapeworm-philosopher might arrive at:

Our tapeworm-philosopher gets its teeth into the subject. Given that the human is so clearly designed to be hospitable to tapeworm-kind, then it follows that if there are more humans, other humans out there beyond the anus, then they, too, must be hospitable to tapeworm-kind. Tapeworm-kind has become aware of itself existing in the human; it is logical to assume that if other humans exist then there must be other tapeworms, and if travel between humans is possible—and we infer that it might be, from the disappearance of our egg sacs through the anus of the human—then sooner or later humans interacting in the broader universe might exchange eggs from these hypothetical alien tapeworms, in which case, visitors! Because the human was already here before we became self-aware, it clearly existed for a long time before us. So if there are many humans, there has been a lot of time for the alien tapeworm-visitors to reach us. So where are they?

Welcome to the Fermi paradox, mired in shit. Shall we itemize the errors that the tapeworm is making in its analysis?

Tapeworm Logic

(Image: segments, a Creative Commons Attribution (2.0) image from istolethetv's photostream)


  1. I’m not sure what Stross is trying do here. Almost every single part of his tape worm analogy fits with a standard analogy for the Fermi Paradox. Something killing tapeworm eggs corresponds closely to the idea that interstellar travel may just be very difficult. And the idea of there being some already existing species which goes around and kills other civilizations has also been proposed. Stross seems to be missing the point of the Fermi question, in that yes, being certain that specific solutions to it are correct is bad, but there’s still a real question here. And figuring out the answer could be important. From the standpoint of the tape worm, there really does seem to be a fair bit of a tape worm great filter http://en.wikipedia.org/wiki/Great_Filter and trying to figure out what that filter is and how to avoid it makes sense. 

  2. “On the other hand, if you want to traffic with the ghost-infested depths of the simulation hypothesis, then anything is possible. Even tapeworm-cosmonauts flying out of my arse …)”

    Ok, now I’m visualizing little rockets shooting from your arse in search of new anuses.

    This has open my mind more than Rule 34…. Thanks Stross!

  3. The tapeworm analogy is limited, but at least it addresses the topic. The best estimate for values for several of the Drake Equation variables have shifted so fast over the last few years of discoveries that Fermi’s question is getting even more interesting.

    Perhaps Dark Matter is just nano-bot clouds from ancient Kardashev type 2.x civilizaitons.

  4. I think Stross is confusing the anthropic fallacy — that Earth or the universe is specially adapted to humans — with the Fermi paradox. Tapeworms marveling at how great the anus is for them (rather than understanding that they evolved to live there and would be different if the anus were different)  is analogous to the anthropic fallacy. The Fermi paradox isn’t just about wondering why we haven’t run into alien humans (or things like Vulcans which are basically the same thing with minor differences), but why we haven’t run into *any* aliens, even ones that are completely different from us because they evolved on completely different kinds of worlds.

    1. The anthropic principle has always seemed like gaia-centric bunkum to me. It’s really just special pleading as a way to try to explain “fine tuning” and is about as testable as saying “spaghetti monster did it”.

      I’m of the opinion that Occam’s razor would favor the idea that we are adapted for the universe, not the other way around. And at least we have basically proven evolution; we have no evidence at all of other universes, and we don’t even have ways to test for them.

    2. Absolutely. It’s when we get conclusions like “The human does not owe the tapeworm a living, or even a comfortable home” that you realize that this article had nothing whatsoever to do with Fermi’s paradox…

  5. Hang on: tapeworms know about radio and haven’t know about the deafening silence their version of SETI has produced?  It’s not a matter of simply not having visitors come by (which may be the case if interstellar space travel is exceedingly difficult).  It’s more that we haven’t heard a damn thing from space that we recognize as artificial.

    1.  I thought that digitally-encoded/spread spectrum radio transmissions basically look like noise, so if other civilizations are like ours, the time window for analog radio emissions is remarkably short.

  6. I think the biggest fallacy in the Fermi Paradox is the implicit assumption that the Great Filter is in our past, rather than in our future.   Eg. we couldn’t have gotten to our level of industrial civilization without a lot of free energy from fossil fuels, maybe there’s a tipping point where, say, things get warm enough to pop the clathrates, and then it’s all over.

    1. I think the radio silence implies, at least, that such a filter for a similar tech development path is close enough to make the window small.

      It does make one wish the Mayans just left giant round signs that said “don’t melt the fucking permafrost, and beware the methane hydrate slush, you stupid shitbirds.”

  7. So if there are many humans, there has been a lot of time for the alien tapeworm-visitors to reach us. So where are they?

    Depending on where and when the particular home human lives, the answer may be: “All around, what are you talking about?”

  8. Tapeworms evolved in a closed system to spread themselves from gut to gut among the guts that were simultaneously evolving within that closed system.  If the human reproductive cycle – or indeed, the reproductive cycles of any life forms that have ever been to Earth – involved shooting all of its babies out into space in hopes that they’d find a suitable host planet, then his analogy would hold up.

    A better analogy would be if the tapeworm started to wonder about guts that might exist outside of the closed system that they evolved in – in other words, whether there was life off of Earth.

    1. shooting all of its babies out into space in hopes that they’d find a suitable host planet

      Maybe there is some kind of tapeworm that we haven’t seen yet, a leadership caste, a hive brain.

  9. I love Stross, be he has missed the point of the paradox.  The real analogy would be if the tape worm had pokes dozens of  probes out of the human’s butt and starts looking around expecting to see other tape worms driving humans around with probes out of their butt screaming into the wind for other tape worms to look at them.  It sees other humans, but no humans with sign of tape worm, and so it asks itself WTF?

    The reason why the tape worm sees no other tape worms in this case is because tape worms are too dumb to manifest themselves outside of their human before they die.  Our tape worm armed with probes coming out of the human butt is unique and the very first one to achieve what it has.

    This is a solution to the Fermi Paradox.  If you crack out Drake’s equation, this scenario is that everything, including life has a non-zero chance, but intelligent life (the kind that sends probes out of butts) is so close to zero as to actually be zero in most or all galaxies.

    The Fermi Paradox combined with Drake’s Equation is supposed to get you to think about very very very large numbers, and realize that if you put anything other than zero into all of the variables for Drake’s Equation, you should have a universe filled with intelligent life that has been around for millions of years.  Clearly, we don’t see a universe filled with intelligent life.  The question is why?  

    Fermi’s Paradox doesn’t offer answers, just something to ponder.  The solution could be as simple as, once a civilization gets a holodeck, they say “fuck this, I’m out” and play games until they all drop dead.  It could be one of the first races looked at Drake’s Equation and said “oh shit!” and so has a bunch of hunter killers roaming the universe snuffing out intelligent life i.e. the ending to Mass Effect 3.  It could be that intelligent races without fail, digitize themselves and lose interest in exploring the physical world.  It could be that intelligent races in their exploration of physics always accidentally press the red button and wipe out their planet.  There are lots of interesting answers.  The point of the Paradox is to ponder them.

  10. But humans DO exchange “visitors” in the form of tapeworms.  Tapeworms run into other tapeworms all the time, just as a matter of fact (depending on where the human lives.)  And they ain’t even really trying.  They’d also run into each other in the sewer even more often.  If they had radios, they’d let the tape-worm philosopher know about it.

    Plus, this tapeworm only has one way to determine if there are other tapeworms:  has one physically entered the same gut I’m in?  

    We have FAR more ways of checking for extraterrestrial life beyond the tapeworm’s metric of: “Has one landed in my backyard?”  We can see 13 billion years into the past in every single direction in every single wavelength, for instance.  This difference creates quite a bit of asymmetry between the two examples.  

    1.  I was going to say something similar to this. In an area where tapeworms are common, a human is likely to become infected with tapeworms more than once. Thus the tapeworms would encounter unfamiliar juvenile tapeworms from time to time. But could they really conclude from this that there were other humans? No. These tapeworms could be the children of the tapeworms of a lone human who came home to live with their parents. Terrible analogy.

      I think the likelier explanation is that there aren’t enough heavy elements around first generation stars for life, to say nothing of civilization, to develop. We are only a few billion years into the second generation. That’s not a lot of time.

  11. Their is really 3 big questions to answer. 1)What exactly would be considered life? How similar does it have to be? 2)What are the real chances of having conditions similar to the earth and the primeval soup to suceed? 3)What are the chances of that happening close enough to us so that we can notice?
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  12. I don’t get it. 

    Isn’t it reasonable to assume that the host with the tapeworm would actually have continued to ingest tapeworm eggs from time to time and thus the tapeworm inside him is likely to have seen evidence of Tapeworm life outside the host? 

    Also, we should change the name to Squirmy’s Paradox now. 

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