The Gaia Hypothesis and the danger of models

Scientists use models -- partial representations of reality, often expressed mathematically -- to explain the universe.  Both working scientists and science teachers often explain those models using analogies.

This has a good result and a bad result.  The good result is that the use of model, analogy, and metaphor makes science accessible for non-scientists.  You don't have to understand piles of abstruse mathematics in order to get a glimpse at the weirdness of quantum theory; if you read last week's post on the Wigner's Friend Paradox, you've seen an example.  In my own teaching, I use analogy all the time.  Antibodies are like trash tags.  Transpiration in plants is like a very long chain attached to the underside of a trampoline.  The Krebs Cycle is like a merry-go-round in which two kids get on and two kids get off at every turn.

The downside, however, is twofold.  The first problem is that it's easy at times to think that the model is the reality.  The goofier the metaphor, the easier it is to avoid this pitfall; I've never had a student yet who thought that the Krebs Cycle really was a merry-go-round (although I did have a student of mine start her essay on antibodies on the AP exam, "So, antibodies are trash tags...").  But with sophisticated, complex models, it's tempting to think that the model is, down to the level of details, what is happening in the real world.

The second downside is that some people will grab the model and run right off the cliff with it.

All of this comes up because a friend of mine asked me what I thought about the Gaia Hypothesis.  I know that this friend to be a sharp, smart, and solid thinker, so I didn't wince, which is what I usually do when someone brings this subject up.  Because I can't think of an idea in science that has fallen so prey to the model vs. reality blur as this one has.

[Image is in the Public Domain, courtesy of NASA/JPL]

Gaia was dreamed up by two scientists of high repute -- James Lovelock and Lynn Margulis -- way back in the 1970s.  The central idea of Gaia is that the Earth's biosphere acts as an interlocking set of self-regulatory systems, and they work together to maintain the homeostasis of the whole in much the same way as organ systems do in an organism.  Lovelock and Margulis identified a number of features of the biosphere, including the carbon dioxide levels, nitrogen levels, oxygen levels, oceanic salinity, and average temperature, that all seem to work through a complex pattern of negative feedback to keep the Earth's systems within a range that is comfortable for living things.  Using computer simulations, Lovelock and Margulis showed that even with a simple model, they could create a "world" that remained stable, and for which the living things played a role in regulation.

All of this is well and good, and Lovelock and Margulis were completely clear about what their model did (and didn't) mean.  (If you're curious, here's the Gaia homepage, run by Lovelock and other scientists working in this field; Lynn Margulis, tragically, died in November of 2011.)

The problem is, lots of people think that the scientists who developed the Gaia Hypothesis meant way more than they actually did.  Part of it was Lovelock's rather inadvisable choice of a Greek goddess's name for christening his model, which brings up lots of images of personified deities, Mother Earth, and New Age nature spirits.  This particular twist really irritates fundamentalist Christians; take a look at the misleadingly named site Environment and Ecology, wherein we find that the Gaia model encourages "radical environmentalism and ecofeminism," because it runs counter to the biblical passage about god giving man "dominion" over the Earth.

Even ignoring the objections of the wacko biblical literalists, I suppose it's natural enough that people could misinterpret Gaia.  The whole thing is just so... suggestive.  And misinterpret it they did, first thinking that because Lovelock and Margulis said that the Earth was like an organism, that they were saying that it was one; and then grabbing the analogy and leaping into the void with it.  As an example of where this can lead, take a look at Truth and Reality: The Metaphysics of Gaia, wherein we find passages like the following:

The GaiaMind Project is dedicated to exploring the idea that we, humanity, are the Earth becoming aware of itself.  From this perspective, the next step in the evolution of consciousness would seem to be our collective recognition that through our technological and spiritual interconnectedness we represent the Earth growing an organ of self-reflexive consciousness.  While we believe that the Earth is alive, and we are part of it, we also affirm the Great Spirit of Oneness found at the heart of all the worlds great spiritual traditions.  What is most important may not be what we believe, but what we find we all share when we put our thoughts aside to go into meditation and prayer together.

I think I can say with some confidence that this is light years away from what Lovelock and Margulis had in mind.  Consider the chain of... I can't call it "logic," what is it? -- to get from Lovelock and Margulis to this stuff:

1. The Earth has interlocking systems that self-regulate, keeping conditions in homeostasis.
2. Organisms do, too.
3. So the Earth is like an organism.
4. Many organisms have organs that allow them to sense, and respond to, their environment.
5. This is called "awareness."
6. Some organisms have a second feature, rather poorly understood, of self-awareness, of the ability to see themselves, their interactions, and their internal mental states.
7. This is called "consciousness."
8. Consciousness is a feature of intelligence, a fairly recently-developed innovation amongst living things on Earth.

Ergo: The Earth is becoming conscious. It'd really be nice of you to pray about it, because that'd help the process right along.

It's all a matter of keeping your head screwed on when you read this stuff; where does the science end and the woo-woo start?  It's always best to go back to see what the scientists themselves said on the topic.  While being a scientist isn't always a guarantee against fuzzy thinking, I'd put more reliance on the ability of your typical scientist to tell fact from fiction than that of someone whose main contribution to the discussion is rambling on in some random blog on the topic.  (Irony intended.)

Still, the use of models is, on the whole, a good thing.  It gives us something to picture, a way to frame our understanding of what is going on in the real world.  You just have to know how far to push the model, and when to quit. It is, in other words, a starting point.  And if along the way it can piss off some creationists, it's all good.

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This week's Skeptophilia book recommendation is a look at one of the most peculiar historical mysteries known: the unsolved puzzle of Kaspar Hauser.

In 1828, a sixteen-year-old boy walked into a military station in the city of Ansbach, Germany.  He was largely unable to communicate, but had a piece of paper that said he was being sent to join the cavalry -- and that if that wasn't possible, whoever was in charge should simply have him hanged.

The boy called himself Kaspar Hauser, and he was housed above the jail.  After months of coaxing and training, he became able to speak enough to tell a peculiar story.  He'd been kept captive, he said, in a small room where he was never allowed to see another human being.  He was fed by a man who sometimes talked to him through a slot in the door.  Sometimes, he said, the water he was given tasted bitter, and he would sleep soundly -- and wake up to find his hair and nails cut.

But locals began to question the story when it was found that Hauser was a pathological liar, and not to be trusted with anything.  No one was ever able to corroborate his story, and his death from a stab wound in 1833 in Ansbach was equally enigmatic -- he was found clutching a note that said he'd been killed so he couldn't identify his captor, who signed his name "M. L. O."  But from the angle of the wound, and the handwriting on the note, it seemed likely that both were the work of Hauser himself.

The mystery endures, and in the book Lost Prince: The Unsolved Mystery of Kaspar Hauser, author Jeffrey Moussaieff Masson looks at the various guesses that people have made to explain the boy's origins and bizarre death.  It makes for a fascinating read -- even if truthfully, we may never be certain of the actual explanation.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Modeling the zombie apocalypse

I usually tell you a little about my topic before I give you my solemn promise that I didn't make any of it up.

This one is so weird that I'm going to put the disclaimer first:

I swear I'm not making any of this up.

A team of medical researchers from two universities in Ottawa have released a paper (published in the Journal of Infectious Disease Modelling Research Progress) containing a mathematical model of what would happen to a population during a zombie attack.

The team was comprised of Philip Munz, Ioan Hudea, Joe Imad, and Robert J. Smith?.  And no, I'm not being tentative, there, with that last name.  The question mark is part of Dr. Smith?'s name.  I wonder how it's pronounced, don't you?   Do you have to say it like a question?  At parties, do people go up to him and say, "Hello there, Dr... Smith?"

Myself, I wouldn't have thought it was legal to have a punctuation mark as part of your name.  But now that I find that apparently it is, I think I'll follow suit.  From now on, my name will be Gordon Bonnet!  That way, people will always seem excited to see me.

In any case, the aforementioned medical research team seems to take the whole zombie-study thing awfully seriously.  Here's the actual abstract of the paper:

Zombies are a popular figure in pop culture/entertainment and they are usually portrayed as being brought about through an outbreak or epidemic. Consequently, we model a zombie attack, using biological assumptions based on popular zombie movies. We introduce a basic model for zombie infection, determine equilibria and their stability, and illustrate the outcome with numerical solutions. We then refine the model to introduce a latent period of zombification, whereby humans are infected, but not infectious, before becoming undead. We then modify the model to include the effects of possible quarantine or a cure. Finally, we examine the impact of regular, impulsive reductions in the number of zombies and derive conditions under which eradication can occur. We show that only quick, aggressive attacks can stave off the doomsday scenario: the collapse of society as zombies overtake us all.

I also have to quote the first line of the paper itself, just because it's so memorable: "A zombie is a reanimated human corpse that feeds on living human flesh [1]."  The coolest thing about this is that they sourced this information.  The source, if you're curious, is The Zombie Survival Guide - Complete Protection from the Living Dead, by Max Brooks (2003, Three Rivers Press, pp. 2-23).

The article then goes on through some amazingly abstruse mathematics to show that a zombie outbreak would be "catastrophic" and could be "disastrous, unless extremely aggressive tactics are employed against the undead."

Have I mentioned that I am not making any of this up?

In the conclusion of the article, Munz, Hudea, Imad, and Smith? state:

In summary, a zombie outbreak is likely to lead to the collapse of civilisation, unless it is dealt with quickly. While aggressive quarantine may contain the epidemic, or a cure may lead to coexistence of humans and zombies, the most effective way to contain the rise of the undead is to hit hard and hit often.

What I find most amazing about all of this is that there was no attempt to tie this to any real, actual epidemic; the whole article was about zombies.  Doesn't that strike you as a little weird?  Now personally, I  love it when scientists take something whimsical and use it as a model for a real phenomenon; one of my all-time favorite studies was when a team of evolutionary biologists used "mutations" (i.e. typos and changes in wording) in chain letters as an analogy to random alterations in DNA, and used it to model how cladistic taxonomy works.  It was sheer brilliance.

This, though... well, I'm not sure I see the relevance.  I can't think of any disease that works anything like, um, zombification, so all of the mathematical twiddling about doesn't really have any apparent application.  Not, of course, that I object to scientists having a little fun once in a while -- but this made it into a peer-reviewed journal, and presumably was the result of a grant from a funding agency of some sort.  Dr. Neil Ferguson, who is one of the UK's top governmental medical advisers, seemed a little uncomfortable when asked about the study.  "My understanding of zombie biology is that if you manage to decapitate a zombie, then it's dead forever," he said, in an interview, and went on to state that other than that characteristic, "zombification" didn't really seem to parallel any known disease particularly well.  "[No infectious illness known] actually causes large-scale death or disease, but certainly there are some fungal infections which are difficult to eradicate."

Smith?, however, was undaunted, and told a BBC reporter, "When you try to model an unfamiliar disease, you try to find out what's happening, try to approximate it.  You then refine it, go back and try again."  Even, apparently, when said unfamiliar disease doesn't, technically, exist.

So, there you have it, then.  A mathematical model for the zombie apocalypse.

Oh, and by the way, if you still don't believe me, here's a link to a BBC article about the study.  In the lower right hand part of the page there's a link that says "Zombies Study (University of Ottawa)" that will allow you to download a free pdf of the entire paper.

Reading all of this stuff leaves me feeling kind of dazed, incapable of doing anything but stumbling around the house with a blank expression, making moaning noises.  Of course, that may be because I'm still waiting for the coffee to finish brewing.  No need to show up at my door with axes.  Honestly.