Sean Carroll

Category: Science

  • Objectivity

    K.C. Cole, moving force behind the Categorically Not! meetings that Clifford has blogged about, has left an interesting comment on Clifford’s post from September on Point of View. It’s provocative (and I largely agree with it), so I thought I would reproduce it here on the front page.

    Now that it’s time for our October Categorically Not!, I finally have a moment to respond to objections some people raised about my September blurb on the subject of Objectivity, or Point of View.

    As a journalist who writes about science, I thought my colleagues could learn a thing or two about the nature of “objective truth” from physics. Objectivity is a word that journalists use a lot—but in my experience, scientists don’t, because it’s not a very useful term. Journalists believe that it’s possible (and desirable) to have zero point of view—that is, to look at the world from some privileged frame through which they see the unvarnished “truth.” What makes science strong, in my opinion, is that it doesn’t fall into that trap. What scientists say is: I made this measurement, and I got this result. Or, I solved an equation, and I got this solution. To say you have a “result” or “solution” without saying how you got it is meaningless. Even when I say the sky is blue, it’s understood that I am a human being whose retina is detecting certain wavelengths of light which are then being interpreted by my human brain in very specific ways. The sky is not “blue” to a snake or a dog or a bee (or if I look through a red filter).

    Similarly, if I say the universe was created in a Big Bang (never mind the details) 13 billion or so years ago, there’s no reason anyone should believe me unless I point out that this particular “objective reality” is based on evidence from several very different points of view (cosmic microwave background, expansion, nucleosynthesis….). Journalists often fail to explain this—which is one reason I believe the whole ID issue has been so badly handled in the press. It’s not enough to say “most scientists think evolution is correct….” That leaves the reader in the position of choosing who to believe—the NAS, or the president, for example. It’s not so difficult, I think, to explain that evolution is an answer to specific questions about the fossil record, morphology, DNA, embryology, etc. But it’s rarely done.

    What really seemed to get people’s goat (goats?) was my statement that how you look at something determines what you see. I fail to understand the problem. If I look at light with a certain kind of apparatus, it’s a wave; if I look with another, it’s a particle. Reality is always reality, but how we choose to ask the question does determine the answer. So the only way to get an “objective” answer to is say how you asked the question! (And if I’m viewing the world through the eyes of an educated middle aged white woman living in LA—which I am—then I’d better take that into account as well.)

    An astronomer friend told me he was upset because my wording played into the hands of the “relativists” (not that kind); that it was understood as “code” to mean “there’s no reality,” or some such. But I’m really tired of other people telling me what my words mean—whether the subject is objectivity, “family values,” “culture of life,” “liberal,” “feminist,” or any of the rest.

    So, yes. Objectivity—meaning looking at a situation from a supposedly privileged frame from which you can see the unbiased “truth” —is, as I said, “not only unattainable, but intrinsically fraudulent and ultimately counterproductive.” Science understands this; it’s journalism that has the problem.

  • Lorentz invariance and you

    Where were we? Ah yes, spontaneous symmetry breaking. When some field takes on a nonzero value even in empty space, and that field is affected by some symmetry transformation, the resulting symmetry is said to be “spontaneously broken,” and becomes hard for us to see directly. The classic example is the electroweak symmetry of the Standard Model, which is purportedly broken by a Higgs field that we have yet to directly detect.

    The fields that get expectation values and spontaneously break symmetries are generally taken to be “scalar” fields — that is, they are single functions of spacetime, not something more complicated like a vector field. If a vector field did get a nonzero expectation value, it would have to point somewhere, thereby picking out a preferred direction in spacetime. That means that Lorentz invariance — the physical symmetry corresponding to rotations and changes of velocity — would be broken. Lorentz invariance is a cornerstone of relativity (and thus of all of modern physics), so breaking it is often thought to be bad.

    vector field

    But really, how bad is it? When Einstein put together special relativity on the basis of Lorentz invariance, he was arguing that there was no absolute space nor absolute time in the sense of Sir Isaac Newton. If two physicists traveling freely through empty space passed by each other at a high relative velocity, we couldn’t tell in any universal sense which one was stationary and which was moving — it’s all relative, if you like. If we violated Lorentz invariance by having a vector field get a nonzero value in the vacuum, we could tell who was stationary and who was moving — the vector would define a preferred rest frame.

    But that’s not quite the same as going all the way back to Newtonian spacetime. The underlying theory is still Lorentz invariant — if we can’t easily detect this vector field (and we obviously haven’t thus far), Lorentz invariance could be spontaneously violated while remaining in complete accord with all experimental tests.

    I was in on the ground floor for this idea — it was the first project I worked on in graduate school (with George Field and Roman Jackiw), and was sufficiently non-mainstream that I worried for my career prospects. Alas, those were more freewheeling times, and you could get a good postdoc without necessarily jumping on a major bandwagon. Subsequently, I was surprised to see Lorentz violation actually become it’s own (relatively tiny) bandwagon! A group of researchers, led by Alan Kostelecky at Indiana, have really pushed the idea of writing down ways to spontaneously violate Lorentz invariance, and have spawned an active experimental program to test these ideas using precision data from astophysics, particle physics, and atomic physics. (Alan has a FAQ on the whole idea of violating Lorentz symmetries.)

    So I occasionally return to the idea, as in work with my former graduate student Eugene Lim on the gravitational effects of Lorentz-violating vectors. And now I’ve returned to it again, this time with current student Jing Shu, as we try to understand a fundamental question in physics: why is there more matter than antimatter?

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  • Hidden symmetries

    Symmetries, you may have heard, play a crucial role in modern physics. (Leon Lederman and Chris Hill wrote a whole popular book about the subject, if you’re interested.) But one of the things that makes them so interesting is that they can be hidden — the symmetry is secretly there, even though you don’t easily notice. And sometimes you may be interested in the converse situation — it looks like there is an obvious symmetry of nature, but in fact there are tiny violations of it, which we haven’t yet detected.

    To physicists, a “symmetry” is a situation where you can rearrange things a bit (values of quantum fields, positions in space, any of the characteristics of some physical state) and get the same answer to any physical question you may want to ask. An obvious example is, in fact, position in space: it doesn’t matter where in the world you set up your experiment to measure the charge of the electron, you should get the same answer. Of course, if your experiment is to measure the Earth’s gravitational field, you might think that you do get a different answer by moving somewhere else in space. But the rules of the game are that everything has to move — you, the experiment, and even the Earth! If you do that, the gravitational field should indeed be the same.

    How do such symmetries get hidden? The classic example here is in the weak interactions of particle physics: the interactions by which, for example, a neutron decays into a proton, an electron, and an anti-neutrino. It turns out that a very elegant understanding of the weak interactions emerges if we imagine that there is actually a symmetry (labeled “SU(2)”) between certain particles; examples include the up and down quarks, as well as the electron and the electron neutrino. (This is the insight for which Glashow, Salam and Weinberg won the Nobel Prize in 1979.) If this electroweak symmetry were manifest (or “unbroken” or “linearly realized,” depending on one’s level of fastidiousness), that means that it would be impossible to tell the difference between ups and downs, or between electrons and their neutrinos.

    Of course, in reality it’s not so hard to tell. These purportedly-indistinguishable particles have some similar properties, but they have different masses, and even different electric charges. Nobody would ever mistake an electron for an electron neutrino. (They would mistake a red quark for a green quark or a blue quark, as those are related by an unbroken symmetry — the SU(3) of quantum chromodynamics, for which the Nobel came much more recently.)

    The reason is that the SU(2) symmetry of the weak interactions is spontaneously broken (or “nonlinearly realized”). The symmetry is firmly embedded in the laws of physics, but is hidden from our view because the particular state in which we find the universe is not invariant under this symmetry. There is something about the vacuum — empty space itself — which knows the difference between an up quark and a down quark, and it’s the influence of the vacuum on these particles that makes them look different to us.

    This idea of spontaneous symmetry breaking has a long history in physics — it was elucidated in condensed matter physics by Philip Anderson (Nobel 1977) and others, and in particle physics by my colleague Yochiro Nambu and erstwhile colleague Jeffrey Goldstone (no Nobel yet, which is a shame). And here’s an interesting thing — if the vacuum is not invariant under some symmetry, there must be some field that is making it not invariant, by taking on a “vacuum expectation value.” In other words, this field likes to have a non-zero value even in its lowest-energy state. That’s not what we’re used to; the electromagnetic field, for example, has its minimum energy when the field itself is zero. But “zero” doesn’t break any symmetries; it’s only when a field has a nonzero value in the vacuum that it can affect different particles in different ways.

    Mexican hat potential The way to do that, in turn, is to imagine that the symmetry-breaking field has a “Mexican-Hat Potential,” as illustrated at right. (Image swiped from The Official String Theory Web Site, which also has a nice discussion at a more technical level.) This is a graph of the potential energy of a set of two fields φ1 and φ2. Fields like to sit at the minimum of their potentials; notice that in this example, the minimum is not at zero, but along a circle at the brim of the hat. Notice also that there is a symmetry — we can rotate the hat, and everything looks the same. But in reality the field would actually be sitting at some particular point in the brim of the hat. The point is that you should imagine yourself as sitting there along with the field, in the brim of the hat. If you were at the peak in the center of the potential, the symmetry would be manifest — spin around, and everything looks the same. But there in the brim, the symmetry is hidden — spin around, and things look dramatically different in different directions. The symmetry is still there, but it’s nonlinearly realized.

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  • I just like saying "phlogiston"

    Well, Steinn has already taken my idea of constructing an entire blog post from this quote from Michael Bérubé, but I’ve decided I’m not too proud to do it anyway. (Andrew Jaffe actually has some things to say.)

    Now, the last time I got together with my editor, on a weekday evening in a midtown restaurant in New York, he flagged the opening pages of the chapter on my postmodernism seminar and said, you might want to watch the mention of Kuhn—because, as you know, there are any number of readers out there who are really tired of humanities professors citing Kuhn and getting him wrong. Likewise with Gödel and Heisenberg on “incompleteness” and “uncertainty.”

    As you might imagine, this remark made me violently angry. Yanking the bottle of pinot grigio from the ice bucket to my right, I smashed it on the edge of the table, stood up, and said, “All right, man. I know all about those readers. And I’m as pissed off about sloppy appropriations of Kuhn as anyone. But let me say one thing.” At this point I had drawn the alarmed attention of all the diners-and-drinkers in the place, not least because I was waving the broken bottle around and making random stabbing motions. “I’ll put my reading of Kuhn up against anyone’s. Anyone’s, do you hear me? DO YOU HEAR ME? I’m serious, man—I don’t just go on about ‘paradigm’ this and ‘incommensurability’ that, people. I can take Kuhn’s examples about phlogiston and X-rays and shit, and I can extrapolate them to Charles Messier’s late-eighteenth century catalog of stellar objects, or the early controversy over the determination of the Hubble constant, or the 1965 discovery of the cosmic microwave background radiation by Penzias and Wilson. GET IT? So don’t mess with my goddamn reading of Kuhn. Any of you.”

    There were a few moments of silence, punctuated only by some nervous clattering of silverware. Then a conservatively-dressed man in his early fifties got up from a table fifteen or twenty feet away. “People like you,” he said, trying to stare me down, “read Kuhn backwards by means of Feyerabend’s Against Method, and as a result, you make him out to be some kind of Age of Aquarius irrationalist who thinks that scientists run from paradigm to paradigm for no damn reason.” Then he tossed his napkin across the table. “And if you want to deny it, I suggest we step outside.”

    In my experience, it’s scientists who get The Structure of Scientific Revolutions wrong more than humanists (or at least as much). Both of them lazily envision Kuhn as a screaming relativist; the difference is that scientists do so with disdain, while humanists do so with approval. Although he wasn’t really very clear about it, Kuhn wasn’t a relativist of any sort; he thought that scientific progress was very real. It’s just not clean and algorithmic, at least during those moments of “revolutionary” science when two very different sets of ideas seem equally plausible. The good news is, the dust always settles, and one paradigm doesn’t overthrow another paradigm just because the new paradigm’s supporters take the old paradigm’s supporters out back and beat them up. Ultimately Nature makes it clear that one idea is just better than another, and all but a few lonely cranks hop on the bandwagon. It’s guessing which bandwagon to hop on in the early stages that is the real fun.

  • Escape from the clutches of the dark sector?

    Dark matter and dark energy make up 95% of the universe — or at least, we think so. Since these components are “dark,” we infer their existence only from their gravitational influences. Some of us have been foolhardy enough to imagine that these observations signal a breakdown of gravity as described by general relativity, rather than new stuff out there in the universe; but so far, the smart money is still on the existence of a dark sector that we have not yet directly detected.

    There remains another possibility worth considering — that there is no dark stuff, and that gravity is perfectly well described by general relativity, but that we just aren’t using GR correctly. In other words, that the conventional theory can explain the observations perfectly well without dark matter or dark energy, we just have to be clever enough to figure out how. This would be the most radically conservative approach to the problem, in John Wheeler’s sense: we should push the smallest number of assumptions as far as they can possibly go.

    Recently, separate attempts have been made to explain away “dark matter” and “dark energy” by this kind of strategy. In a paper that somehow got mentioned in the CERN Courier and on Slashdot, authors Cooperstock and Tieu have suggested that nonlinear effects in GR could explain flat rotation curves in spiral galaxies (one of the historically important pieces of evidence for dark matter). And in two papers, Kolb, Matarrese, Notari and Riotto and then just Kolb, Matarrese, and Riotto have suggested that nonlinear effects in GR could explain the acceleration of the universe (a key piece of evidence for dark energy). Are these people making sense? Are they crazy? Is this worth thinking about? Have they actually explained away the entire dark sector? (Answers: occasionally, possibly, yes, no.)

    In both cases, the relevant technical issue is perturbation theory, specifically in the context of general relativity. Imagine that we have some equation (in particular, Einstein’s equation for the curvature of spacetime), and we’d like to solve it, but it’s just too complicated. But it could be that physically interesting solutions are somehow “close to” certain very special solutions that we can find exactly. That’s when perturbation theory is useful.

    Call the solution we are looking for f(x), the special solution we know f0(x), and the small parameter that tells us how close we are to the special solution ε. For example, gravity is weak, so in GR the small paramter ε is typically something proportional to Newton’s constant G. Then for a wide variety of situations, the sought-after solution can be written as the special solution plus a series of corrections:

    f(x) = f0(x) + ε f1(x) + ε2 f2(x) + …

    So there are a series of functions that come into the answer, each of which is accompanied by a progressively larger power of ε. By only knowing the first one to start, we can often plug that solution into the equation we are trying to solve, and get an equation for the next function fi(x) that is much simpler than the full equation we are struggling to solve.

    The point, of course, is that we don’t really need to get the whole infinite series of contributions. Since ε is by hypothesis small, every time we raise it to a higher power we get smaller and smaller numbers. Often you do more than well enough by just “going to first order” — calculating the εf1(x) term and forgetting about the rest. But it’s certainly possible to get into trouble — for example, there could be “non-perturbative effects” that this procedure simply can’t capture, or the perturbation series itself could be sick, for example if the function f2(x) were so huge itself that it overwhelmed the extra factor of ε it comes along with. We would then say that perturbation theory was breaking down.

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  • Infrared Andromeda

    NASA’s infrared Spitzer satellite has released these gorgeous new images of the Andromeda galaxy. In infrared, you are directly observing the dust lanes that describe the galactic arms, rather than simply looking at reflected starlight.

    Andromeda galaxy

    Here’s a bigger version. Lyman Spitzer, after whom the telescope is named, was one of the primary movers behind the original Space Telescope idea, which eventually grew into the Hubble Space Telescope. He was also my grand-advisor: George Field was my Ph.D. advisor, and Spitzer was his.

  • Scientists look for dinosaurs, dig up humans instead

    Last year I was fortunate enough to join the folks at Project Exploration on an honest-to-God dinosaur expedition, digging up fossils in Wyoming. PE is a great organization, headed by educator Gabrielle Lyon and paleontologist Paul Sereno, that works to get kids interested in science. I wasn’t able to make it to Wyoming this year (I was enjoying croissants in Paris, as I recall), but I wanted to point to PE’s latest project: a set of field updates on the web about a recent expedition to Niger.

    Sereno has led several expeditions to Niger to search for fossils, coming back with such discoveries as an astonishing skeleton of SuperCroc (or Sarcosuchus Imperator, for you sticklers out there). During the 2000 expedition, the team stumbled across a remarkable find: remains of a Neolithic human settlement, perhaps 5,000 years old, with about 200 human skeletons in addition to countless artifacts of various sorts. Not being really equipped to take advantage of the find, the team protected the fossils as well as they could, with the idea of teaming up with archeologists and coming back later to excavate the site.

    Paul Sereno and Shureice Kornegay

    That return trip was just recently undertaken, and one of the team members was Shureice Kornegay, a graduate of PE’s Junior Paleontologist program who is now attending Norther Illinois University. Shureice and Paul have been writing these field updates that convey some of the excitement and challenge of such a major undertaking as this expedition. It’s great to read along as they cope with tipping water trucks and insect swarms of “biblical proportions.”

    Some details about the expedition can be found in this communication to the team (pdf), which will fill you in both on the background of the site, and on what you need to bring with you when you’re about to head out to the Sahara to dig for bones! It’s good to be occasionally reminded that physics isn’t the only exciting science out there.

  • The world is not magic

    Here is a true story. Saturday, after the symposium at Fermilab, I was driving back into the city. To be honest, I was completely exhausted; it had been a long day of talks, and I had been up quite late the previous night throwing mine together, resulting in very little sleep. So I was pretty much ready to crash, certainly uninterested in any sort of activity involving serious brain function.

    And then I remembered that the big football game was about to start — my beloved Penn State Nittany Lions vs. the Ohio State Buckeyes in a titanic battle for Big Ten supremacy. Sadly, however, I don’t have cable TV at my place (long story). But I knew how to circumvent this obstacle: a visit to ESPN SportsZone, the modern sports-bar/video arcade that features comfy leather recliners in which you can grab a bite while you watch the game on their huge-screen TV. A perfect brain-free activity to cap off the evening. Very un-physics-professor-like behavior, but I’ve done worse. And if all went well, Penn State would even win, preserving their unbeaten record and vaulting them into the national-championship picture.

    (Aside: they did win, outlasting 6th-ranked OSU for a rain-soaked 17-10 victory in front of 100,000 screaming Penn State partisans. An incredibly important victory for the program and for legendary coach Joe Paterno, who had inexplicably suffered through four losing seasons in the last five years. Paterno has been head coach for 40 years, including 20 bowl victories (best ever), 349 total victories (second-best), five undefeated seasons, and two national championships. He’s also donated millions of dollars to the university — to build a library. When Penn State joined the Big Ten a dozen years ago, Paterno was 66 and widely expected to soon retire. When Barry Alvarez steps down from the head job at Wisconsin at the end of this year, every school in the conference will have experienced a head-coaching change — except Penn State. Due to the travesty by which college football chooses its national champion, it will be difficult for PSU to get a legitimate shot at the title this year even if they win all their games. But if things break just right, the Lions could be headed to the Rose Bowl on January 4th to duke it out with USC for the big enchilada. Watch out, Clifford, we’re coming for you!)

    So there I am, enjoying my buffalo wings and Guinness and cringing as Ohio State scores the first field goal. At the table next to me was a group of women who were visiting the big city for the weekend, celebrating the birthday of Caroline, one of their number. They were also Ohio State fans — no accounting for taste. It’s perfectly clear within the restaurant who is rooting for which team, just from the timing of shouts of delight or groans of dismay, so we were soon trading good-natured barbs about the relative merits of our respective squads.

    By halftime Penn State was up 14-10, so I was feeling especially magnanimous. We chatted about what we all did for a living and so forth, and I ended up explaining something about dark energy and particle physics and the big bang. Caroline, after making a good-faith effort to understand the distinction between quarks and leptons, pleasantly but firmly demanded to know “What is the practical use of all this? What can we actually do with it? Why is it worth spending time on it?”

    My line on these questions is that there isn’t necessarily any practical application (although there may be spinoffs); we do it as part of a quest to understand how the world works. I was trying to explain this, with less than complete success. But then Caroline’s younger sister (whose name I unfortunately forget, as I would love to give her credit), who was a secondary-school science teacher before she had kids of her own, leaned across the table and said “Because the world is not magic. This is what I always taught my kids, and it’s what everyone should understand.”

    The world is not magic. The world follows patterns, obeys unbreakable rules. We never reach a point, in exploring our universe, where we reach an ineffable mystery and must give up on rational explanation; our world is comprehensible, it makes sense. I can’t imagine saying it better. There is no way of proving once and for all that the world is not magic; all we can do is point to an extraordinarily long and impressive list of formerly-mysterious things that we were ultimately able to make sense of. There’s every reason to believe that this streak of successes will continue, and no reason to believe it will end. If everyone understood this, the world would be a better place.

    Of course, there are different connotations to the word “magical.” One refers to inscrutable mystery, but another refers simply to a feeling of wonder or delight. And our world is full of that kind of magic. I get to listen to some fascinating talks on neutrinos and particle accelerators during the day, enjoy a statement-making victory over our conference rivals in the evening, and be handed a nugget of marvelously distilled wisdom from a woman in a sports bar who I had never met and will unlikely ever see again (a Buckeye fan, no less) — these are all magical. We shouldn’t feel disappointed that the march of understanding removes an element of mystery from the world; we should be appreciative of how much there is to know and the endless variety of ways in which our sensible universe continues to surprise us. The very fact that our world is comprehensible should fill us with wonder and delight. The world is not magic — and that’s the most magical thing about it.

  • Einstein speaks

    Einstein Yesterday I gave a talk at a Fermilab symposium celebrating the World Year of Physics. It was a great event, aimed mostly at local high-school students and the public more generally, although personally I learned alot from the other talks myself.

    My own talk was an overview of special and general relativity; you can see the slides here (warning: large pdf file). Eventually I think all the talks will be in video on the symposium web page. I played an audio file featuring Einstein himself explaining the basics of that equation E = mc2 that we were talking about a while back. People were asking me where I stole it from, so here’s the answer: an Einstein exhibit at the American Institute of Physics website. Give it a click; it’s nice to hear the master himself talk about his formula, thick German accent and all.

  • So much to blog, so little time

    Things I would talk about at greater length and erudition if I were a man of independent means, rather than someone who supposedly works for a living. Also, today is my birthday; instructions on how to honor this auspicious occasion appear at the end of the post.

    First, Henry Farrell of Crooked Timber has an eloquent article about academic blogging in this week’s Chronicle of Higher Education, “The Blogosphere as a Carnival of Ideas.” The final paragraph sums it up:

    Both group blogs and the many hundreds of individual academic blogs that have been created in the last three years are pioneering something new and exciting. They’re the seeds of a collective conversation, which draws together different disciplines (sometimes through vigorous argument, sometimes through friendly interaction), which doesn’t reproduce traditional academic distinctions of privilege and rank, and which connects academic debates to a broader arena of public discussion. It’s not entirely surprising that academic blogs have provoked some fear and hostility; they represent a serious challenge to well-established patterns of behavior in the academy. Some academics view them as an unbecoming occupation for junior (and senior) scholars; in the words of Alex Halavais of the State University of New York at Buffalo, they seem “threatening to those who are established in academia, to financial interests, and to … well, decorum.” Not exactly dignified; a little undisciplined; carnivalesque. Sometimes signal, sometimes noise. But exactly because of this, they provide a kind of space for the exuberant debate of ideas, for connecting scholarship to the outside world, which we haven’t had for a long while. We should embrace them wholeheartedly.

    This business about certain academics viewing blogs as an unbecoming occupation is more true that I’d like to admit (although it is far from universal). And it extends to all kinds of pretentions to public-intellectual engagement, not just our daily interventions on the internets. Which is why it’s important to emphasize that true scholarship entails two tasks, both equally crucial: discovering new things about the world, and letting people know what it is we have discovered. The first is called “research,” while the second is sufficiently undervalued that we don’t even have a good name for it. Part of it is “education,” part is “outreach,” part is engaging in public debate. But whatever you want to call it, it is just as important as research itself. You might say that, without research, there wouldn’t be anything to outreach about. True, but if we never told anyone what we had learned, there wouldn’t be any reason to do research, at least not in intellectually-driven fields like cosmology and history and literary criticism. It’s like asking whether, in baseball, the bat or the ball is more important. Without either, the whole thing becomes kind of pointless.

    Next, Abhay Parekh at 3quarksdaily asks what it is that makes people disbelieve in evolution. He points the finger of blame at the “decent with random modification” part of natural selection:

    My explanation is simply this: Human beings have a strong visceral reaction to disbelieve any theory which injects uncertainty or chance into their world view. They will cling to some other “explanation” of the facts which does not depend on chance until provided with absolutely incontrovertible proof to the contrary.

    I’m sure that’s part of it, although I suspect the truth is a complicated mess that varies from person to person. Others chime in: Lindsay at Majikthise thinks it’s about disenchantment and an absence of meaning in purely naturalistic theories of the universe; Amanda at Pandagon chalks it up to a need to feel superior to other species; PZ at Pharyngula points to the psychological drive to be part of something bigger. I think all of these are likely part of it, and would add another ingredient to the cocktail: resentment at being told what to think by arrogant elites. When people use “local choice” as an excuse to allow school boards to decide to teach all sorts of nonsense, defenders of evolution generally treat it as simply a tactic to further their religious agenda. For the Discovery Institute et al. that is no doubt correct; but for people on the streets who are speaking at the school board meetings, I suspect a lot of it it really is about local choice. They don’t like to be told by some mutiple-degreed Ivy League east-coast intellectual types that they should think this and not that. There is a particularly American cast to this kind of resentment, which helps explain why this poor country is so much more backward about these issues than our peers in Europe.

    Finally, speaking of Lindsay, she has recently embarked on quite an adventure: inspired by the experience of reporting on-location in the aftermath of Katrina, she’s quit her regular job to become a full-time stringer. But she needs some help at the early stages, so this week she’s asking for donations in turn for by-request blogging! This sort of bottom-up structure is alien to us here at Cosmic Variance, where we figure we’ll write about what we think is best and you’ll like it, or learn to. But it’s an interesting experiment. And while you have your PayPal account handy, you could drop by to Shakespeare’s Sister, who was recently hit by a double whammy when she was laid off from her job and had her property taxes increased by 100%. She’s one of the most passionate and articulate bloggers we have, and if you like what you read there, don’t be shy about dropping off a couple of bucks.

    That would make me a good birthday present.