Preposterous Universe

 
Extra dimensions

Last night at a jazz club I was talking to a graduate student at the UofC Divinity School, trying to explain the concept of extra dimensions of spacetime. The possibility of extra dimensions is one of the most exciting ideas in modern physics, but also the one I've had the most trouble elucidating to non-experts. (For noble attempts, see here, here, here, here, here.) I'm not completely sure why this is the one thing that is hardest to understand.

How do we know there are three dimensions of space? The simplest way is to take a set of meter sticks and tie them together, such that every one is perpendicular to every other one. What is the largest number of sticks for which you can do that? Three. If we lived in a world with two spatial dimensions, it would only be two, but if there were extra large dimensions it would be some bigger number. Given that we have developed mathematical techniques for describing the geometry of one-dimensional curves, two-dimensional surfaces, and three-dimensional spaces (not to mention four-dimensional spacetime), it shouldn't be too surprising that we can straightforwardly generalize to higher numbers of dimensions. But people who spend their free time doing something other than studying mathematics don't want to hear that -- they want to know how you can visualize all these extra dimensions. We try our best, but ultimately you can't really do it, and you have to resort to metaphor.

When trying to explain extra dimensions, there are a few standard analogies we always trot out. One is a straw, or garden hose. We can idealize a straw as a two-dimensional cylinder, but if you look at it from very far away it looks essentially one-dimensional. This is supposed to capture the idea that there can be extra compact dimensions at each point in space. I think this analogy is perfectly transparent, and everyone who hears it should instantly comprehend this otherwise difficult concept. But the actual reactions run the gamut from blank stares to gently-furrowed brows. (A very tiny gamut.) When I'm trying to explain this in a radio interview, it's even worse, as the complete lack of visual aids renders me helpless. Is there some better metaphor lurking out there?

If string theory is right and there are seven extra dimensions curled up at every point in our apparently three-dimensional space, we are actually smeared out uniformly throughout these dimensions. This smearing can ultimately be traced back to our status as relatively low-energy phenomena in the universe. Something physicists take for granted is the connection between energy and distance: to access phenomena at very small scales (like a tiny curled-up extra dimension) requires the focusing of extremely high energies. That's why we're hoping to find evidence for extra dimensions at particle accelerators. It's a long shot, though; we're gradually increasing our reach in energy, but it wouldn't be a surprise if the extra dimensions were well beyond our currently conceivable experiments.

Probably the best way to explain extra dimensions is to imagine that there were fewer dimensions, and how inhabitants of these lower-dimensional worlds could be convinced of the existence of three spatial dimensions. This was the strategy taken in Edwin Abbott's classic social satire Flatland. Let's not forget, however, that once the protagonist is convinced of the existence of extra dimensions and starts spreading the word, he's thrown into jail for his subversive ideas.

Although I didn't really succeed in conveying much understanding about extra dimensions, I did learn something about the divinity school: many, if not most, if its faculty members don't believe in God. "Pretty skeptical about religion" was the description offered. I wonder if this phenomenon is widespread in divinity schools elsewhere?

~ posted by Sean Carroll at 4:23 PM ~ link ~ ~ ~

 
First impressions

Jarhead by Anthony Swofford is an account of Swofford's experiences as a young Marine in the first Gulf War. It's a riveting book, well worth reading, especially for the description of the training and culture of the Marines. There is not much combat in the book, largely because the combat phase of the war was so short. But there is some interesting insight about the relations between the U.S. forces and the local population. This story takes place in Saudi Arabia, after a small group of Marines have encountered a tribe of Bedouins who were complaining that someone had been using their camels for target practice.

We drive back to the Triangle on the superhighway and I sit in the back of the Hummer with Dettmann and Crocket and tell them what occurred with the Bedouins. They think the story is funny, and they both laugh and make jokes about "camel jockeys." I'm not happy to be in the Triangle, and I'm even less happy about going to war as a hired man for another government, but I find their heartlessness particularly disturbing. I want to defend the Bedouins against this assault from these ignoramuses.

The Bedouins are not our enemy, and the Bedouins will not try to kill us whenever the Coalition decides to act. I've just experienced a human moment with the Bedouin, free of profanity and anger and hate. Because they are ignorant and young and have been well trained by the Corps, Dettmann and Crocket are afraid of the humanity of the Bedouin, unable to see through their desert garb into the human.

Before I have a chance to tell Dettmann and Crocket the reasons they are wrong, before I have an opportunity to explain the difference between the Bedouin and the Iraqis, a Mercedes sedan approaches from the rear, traveling at high speed. We occasionally see large Mercedes sedans on the superhighway, a Saudi male driving with a female or a few females in the backseat, each wearing a hijab, the traditional Muslim head covering. These brief, high-speed glances are our only exposure to the citizens of the country we're protecting (the Bedouins are less citizens of the country than denizens of the land). We're sure the Saudis prefer this arrangement. We are the ghost protectors. As the car closes in, Crocket stands in the back of the Humvee, holds the crossbar with one hand, and puts his other hand to his mouth, flicking his tongue between the two fingers. The driver of the Mercedes turns his head slowly, a little late to see Crocket, but one covered woman sits alone in the backseat of the car, and I watch her eyes follow Crocket's rude gesture. I don't know if she's registering shock or confusion or disgust, but I know I will always remember her eyes, locked on the crude young American.

The Mercedes blows past and Crocket and Dettmann yell profanities and excitedly slap each other on the back. Dettmann calls Crocket a "ballsy motherfucker," and Crocket says, "That bitch will never forget me. She wanted me."

It's not hard to see why sending our armed forces into a foreign country tends not to be an effective way to capture hearts and minds. The Marines are nineteen-year-old kids, far from home and trained in the difficult and specialized arts of winning wars. They are not a skilled cadre of career diplomats. And that's the way it should be; empathy for the Other is not a skill that helps soldiers win battles, and might even help you get killed. Being a fighter is different than being a negotiator or statesman. If we are going to make a habit of nation-building in countries that aren't fully convinced of our benevolence, we're going to have to figure out better ways to manage the transition from battle to rebuilding.

~ posted by Sean Carroll at 7:32 PM ~ link ~ ~ ~

 
Democracy is coming

Here's hoping that all goes relatively well for the people of Iraq, who were graciously handed their sovereignty a couple of days early. Even if their new government arose out of the fevered imaginations of crypto-imperialist neoconservatives, we should all wish that the experiment with democracy turns out to be a true success. I don't have much reason to believe that a real government by the people has a better chance of taking hold in Iraq than it does in, say, Russia, but I absolutely hope I'm wrong.

Meanwhile, the rule of law seems to be catching on in the United States as well, as the Supreme Court has used their combined legal acumen to determine that the President does not have the right to detain people for years without bringing charges or any access to the court system. It feels like a Leonard Cohen song is breaking out.

(Sorry for not linking to any other clever blogospherical thoughts on these weighty matters -- still running around in headless-chicken mode.)

~ posted by Sean Carroll at 7:24 PM ~ link ~ ~ ~

 
Modern cool

Occasionally the demands of the tangible world -- unpacking after a recent move, for example, or even trying to be a good scientist -- make it hard to indulge in blogging. Fortunately, wiser minds than my own have developed all sorts of coping strategies, such as the Sunday Song Lyrics you'll find at the Volokh Conspiracy.

So here is a Sunday Song Lyric of my own. In honor of moving, I'll offer up the first song that really struck me upon moving to Chicago five years ago: Patricia Barber's Postmodern Blues (punctuation as in original liner notes):

as the century ends and tradition turns in on itself
as Boulez screams and yells his music is put on the shelf
repetition is back, a rose is a rose, said herself
Bill Gates has won
i've got the postmodern blues

1900 began the obsession with function as form
with a hammer and nail and a paintbrush and camera they storm
in Russia the Bolsheviks conquer, the masses want more
Karl Marx has gone,
i've got the postmodern blues

line is fragmented, Isadora invented modern dance
philosophers ponder while communists squander their chance
illusion is captured in Cubism's reign over france
Picasso's gone
i've got the postmodern blues

the stock market rallies as futures are tallied and sold
pensions are raided and parachutes painted in gold
conformism packaged to save us all from the cold
Cezanne is gone
i've got the postmodern blues

I love Barber's lyrics, but they're not her strong suit -- take your pick from singing, composing, and playing the piano, she's fantastic at all of them. Although "jazz" would be the idiom you'd squeeze her into if you were so inclined, she is heavily influenced by classical music (her original training) and is somewhat celebrated for startling interpretations of pop tunes (both "Light My Fire" and "Ode to Billy Joe" are personal favorites of mine). The All-Music Guide sums her up pretty well: "Quirky, Cerebral, Ambitious, Playful, Melancholy, Sophisticated, Stylish, Intimate, Bittersweet, Freewheeling."

Best of all, she plays (most) Monday's at the Green Mill here in Chicago, five dollar cover in a cozy and historic venue. Another reason this is the world's greatest city.

~ posted by Sean Carroll at 10:22 PM ~ link ~ ~ ~

 
Homeward bound

No time for blogging, I've just become a homeowner. Yesterday was closing -- the first time in my life I have ever hired an attorney. (Before, I just knew them as those really competitive people in the intramural basketball league.) Today I actually moved, although much remains to be done. A phone/DSL line, for example; this is being typed from an internet cafe, where I have escaped to after discovering that none of my telecommunication services were working yet.

Another change wrought by my new status: until recently, I'm pretty sure I had never actually set foot inside a Home Depot. Now I am practically friends with all the staff. And I have designed a truly ingenious way to use my bookshelves as a CD rack, of which I am undeservedly proud.

The whole process involves so many failure modes that it's very frightening to contemplate. (For example, don't just park in the alley and leave your hazard lights flashing for too long, as you might drain your battery and be unable to start your car -- not that I know from experience, you understand.) The key is a good real estate agent, and I was lucky enough to have a true genius on my side -- Ed Jelinek, whom I heartily recommend to anyone looking to buy property in Chicago. Putting yourself in the hands of someone who really knows what they are doing, and makes extra efforts to look out for you and set you straight when you are about to make a horrible mistake, makes an intimidating process immeasurably less scary.

~ posted by Sean Carroll at 5:06 PM ~ link ~ ~ ~

 
Vacuum popularity

Okay, folks out there in internet-land, help me out here. Did vacuum energy just surge in popularity all of a sudden? If you look for "cosmological constant" in Google or other search engines, one of the first things that comes up is a short article I wrote for the Encyclopedia of Astronomy and Astrophysics some time back. On an average day there might be ten or so hits on that web page; but thus far today there have been well over two hundred, from a collection of different search engines. Did the cosmological constant get mentioned on Oprah or something? (And, more importantly, how can I make money off of this?)

~ posted by Sean Carroll at 9:00 PM ~ link ~ ~ ~

 
Precognition

You knew it, right? There was something inside you, as you read just yesterday about the startling evidence of an actual link between Iraq and Al Qaida, maybe even a direct tie to Sept. 11? There was some nagging feeling that it couldn't be true. There's been no evidence worth talking about for any such connection, and it would be very strange for it to suddenly pop up now. Who knows, maybe they did something incredibly bone-headed yet again, like mixing up two kinda-Arabic-sounding names. Ha, ha! Wouldn't that be ridiculous? Any idiot would have cleared something like that up a long time ago.

I'm sure glad this stuff isn't important, so we can all just enjoy a good laugh about it.

~ posted by Sean Carroll at 9:31 PM ~ link ~ ~ ~

 
What would Shelly do?

A gaggle of Nobel Laureates in Chemistry, Physics, and Medicine have endorsed John Kerry for President, on the (sensible) grounds that the Bush administration is undermining science in countless ways, from cutting funding for basic research to ignoring honest input on bioethics issues. Probably most of these folks are good liberal academics who would have voted Democratic anyway, but the administration's specific affronts to science are what made them get together to sign the letter.

Like Chris C. Mooney, I wonder how much impact such a letter will have. It got a good amount of play on the news, and polls typically indicate that the public has a high regard for the honesty and ethical standards of scientists (compared to journalists, prostitutes, car salesmen, politicians, etc.). But as Chris says, people don't turn to scientists for policy guidance the way they used to (or we imagine they used to, anyway).

I think the laureates are doing the right thing by intervening, though. If Sheldon Glashow wants to give his opinion about globalization or literary theory, his expertise as a particle physicist don't count for very much; but in a letter focused sharply on science policy, they have every reason to stick their noses in the debate. And in a society that takes your opinion about world peace seriously once you simply demonstrate your ability to carry a tune or look good on screen, why shouldn't people with actual expert knowledge about a field make their judgments known?

~ posted by Sean Carroll at 6:58 PM ~ link ~ ~ ~

 
Rawls

Brian Leiter points at a memorial notice for the late John Rawls, one of the leading (probably the leading) American political philosopher of the twentieth century. I got to know Rawls just a little bit, when as a graduate student I sat in on one of his classes. He was both one of the warmest and one of the most intelligent people I have ever had the privilege to meet.

The class I took was offered both to undergraduates and graduate students; there were twice-weekly lectures, plus weekly discussion sections. The sections for undergrads were led by philosophy grad students, while Rawls himself led the session for grad students. I asked whether I could sit in on the grad-student section, given that I was an astronomy grad student who was merely auditing the class; being the paragon of fairness that he was, he said that since I was a grad student, I should go to the section for grad students, simple as that.

Unfortunately, I almost never got to talk with him about philosophy; once he found out that I was interested in cosmology and the early universe, he was always asking me questions about that. He had wide-ranging interests in math and science, and would often use metaphors in the lectures that I'm sure nobody but me could appreciate. The best was when he said that deriving his two principles of justice should be like proving Stokes' theorem in differential geometry on an arbitrary manifold: it required a large investment to set up the definitions and axioms, but then the proof was almost immediate. He also had a standing offer of $100 to anyone who could find a "mistake" in his theory of justice as fairness, in the sense of an incorrect conclusion drawn from his premises. He believed that good philosophy should be like good mathematics; it need not be "right" (if you didn't believe in the premises), but it could be free of mistakes.

He influenced my own views a great deal, moving me from a confused utilitarianism to a fervent social-contractarianism. A rare combination of genius and genuine humanity.

~ posted by Sean Carroll at 5:55 PM ~ link ~ ~ ~

 
God: threat, or menace?

I've learned from experience that the way to get a lot of comments is to claim that God doesn't exist. Some of the comments, unfortunately, seemed to imply that the statements in my post were naive, simplistic, patronizing, etc. My response was basically that the post was indeed simplistic, but not naive (patronizing I will leave as a judgment call); I was just blurting out some things I believe are true, in a rhetorically oversimplified fashion, and not trying to give any sophisticated arguments just then. But it wouldn't hurt to be more careful and explain what I actually do believe, even if restrictions of space, time, and interest mean that I'll still be pretty superficial about the reasoning.

One problem with "God" is that nobody agrees on the definition. Of course it's useless to argue about the "correct" definition, but we should agree on what we're talking about. So, when I say "God", I am thinking of something we would recognize as a conscious being, unique in the universe and playing some important role in its creation and/or maintenance, with apparently supernatural abilities (maybe omnipotence or some similar degree of ability, but certainly way above anything we're familiar with in everyday life). For many academic theologians (although certainly not all), the sticking point there is likely to be the "conscious being" part. In particular, I don't want to use "God" to refer to nature itself, or to a feeling we get in certain sacred situations, or to the abstract laws of physics, or to our capacity for joy and love, or anything so insentient. Those things might be interesting to talk about in their own rights, but I don't see why we should call them "God" -- they are quite different from the God of classical Abrahamic monotheism, as well as from an Aristotelian unmoved mover responsible for creating the universe. Nor are they what 90% of the 90% of Americans who profess belief in God really mean when they profess that belief, I'd be willing to wager. Whatever most people have in mind when they speak of God, it must be some being that is able to care about we humans. (If you'd like to define God as all of nature or as our love for our fellow persons, then fine, I agree that God exists. But as a good pragmatist who sees no practical consequences flowing from such an identification, I wonder why we should bother. Why not just use a different word?)

So, do we have reason to believe that God exists? There are two possibilities: either the existence of God is a logical inevitability and can be demonstrated through pure reason, or God is possible but not necessary and we must turn to experience, revelation, or something otherwise more contingent.

I honestly don't know what it would mean for some aspect of reality to be logically necessary; logical necessity is a characteristic of formal statements, not of the real world. Our descriptions of the world might involve certain logical requirements, but the world is whatever it is. In particular, there is absolutely no obstacle to imagining a world without God. It is perfectly straightforward to imagine a strictly mechanistic universe, consisting of certain dynamical objects obeying a set of immutable rules. (In Aquinas and elsewhere you can find the idea that the universe requires a First Cause to keep it all moving. Everyone these days should recognize that this is a perfect example of how you can trick yourself by sloppy use of language; ever since Newton, we've understood that motion is a perfectly natural state of being, and doesn't require any agent to keep it going.) I furthermore see no obstacle to imagining that some of those objects get together to form complex collections possessing what we would call "consciousness." (The details of how it might happen remain to be worked out, but that's not an obstacle in principle.) Such a universe could easily last forever as a self-contained entity, without the aid of any external creator or first cause. Indeed, I think our universe is really like that. And since I can perfectly well imagine it, there's no way to use pure reason to argue that it's not possible; we have to turn to the actual universe we find ourselves in to determine if God is playing a role.

So we need to examine our particular universe and decide whether it looks like God is a part of it or not. Of course, we ourselves are part of the universe, so we might in principle be able to look purely inside ourselves, appealing to contemplation or even revelation. Personally, I find those methods completely unreliable; we could come to all sorts of absurd conclusions by trusting them. Instead, we should be good empiricists, and try to judge as objectively as we can whether our universe makes more sense with God or without. In other words, we should consider the idea of God as any other hypothesis about how nature works, and test it using conventional scientific methods.

Although natural theology has a long history, it's not an especially distinguished one, with the argument from design taking an especially heavy beating (from Hume even before Darwin). Consequently, a lot of people don't like the idea that we should treat God as an hypothesis to be empirically tested. Stephen Jay Gould tried to argue that religion and science are compatible because they are strictly non-overlapping in their spheres of interest. But if you look hard at his argument, it only makes sense because his definition of "religion" is what most people would call "moral philosophy." It's certainly true that religion has important aspects other than a theory of the nature of reality -- moral and social aspects, most obviously. But it also makes claims about how reality works, and those claims can be tested by the same criteria that other claims about reality can be tested. (Furthermore, if the claims about reality fail to be supportable, there doesn't seem to be much reason left to put any stock in the moral or social aspects -- but that's an entirely separate kettle of fish.)

By the standards of conventional scientific reasoning, the idea that there exists a God that plays an important role in the universe does very badly as an hypothesis, as I've discussed in some detail elsewhere. Everything we've ever seen in the universe is completely compatible with a purely naturalistic description; we've never seen any reliable evidence of supernatural influence or design, and adding an entirely new metaphysical category to a perfectly self-sufficient universe is an unnecessarily drastic step in our attempts to fill in those gaps that remain in our understanding. (Again, plenty of people disagree; the argument from design is alive and well, and now typically refers to the exquisite perfection of the laws of nature rather than to the human eye. I just think adherents of this view are wrong.) It didn't have to be this way; I could equally well imagine a universe in which evidence for the existence God were quite manifest, with good alternate-universe scientists who were among the most devout members of society. It's just not the universe in which we live.

Of course mine is a minority view, if we were to take a poll among all the people in the world. That's exactly the reason why it's worth pressing the issue. It wouldn't be fair to call belief in God the Big Lie, as the people who argue in its favor are generally quite sincere. But it is the Big Mistake; of all the incorrect beliefs in the modern world, this is certainly the one that combines the widest prevalence with the most significant impact. So it's worth arguing against, gently but persistently.

Not that I expect to change anybody's mind (although one theologian did tell me that I had convinced him to give up on the argument from design, if not on belief in God). But at least now I can point to this post if the issue arises again, so the blog can concentrate on important issues like ice cream and performance art.

~ posted by Sean Carroll at 8:46 PM ~ link ~ ~ ~

 
Blog news tidbits

Good news and bad news here at Preposterous HQ. The good news is, we've added a Google search to the site -- find it near the bottom of the right-side column. (I noticed this gizmo at Christina's LIS Rant.) Now you can find out how many times I have mentioned Einstein (9), God (8), or Bush (16). Something should be done to redress the balance there.

The bad news is this paragraph I came across at Blogshares:

Preposterous Universe suffered a huge setback with several analysts urging their clients to ditch the stock as it suffered a public relations disaster. The exact nature of customer dissatisfaction was not known but Alan Dean was rumoured to have had a hand in it. Industry insiders suspect a Schroedinger's Cat (artefact) was involved. Preposterous Universe share price dropped from B$745.92 to B$305.83.

I think I might be worried/sad/philosophical, if only I had any idea what any of it meant.

~ posted by Sean Carroll at 3:11 PM ~ link ~ ~ ~

 
Wild & crazy

This is an image of the comet Wild 2 (pronounced "Vilt"), taken by NASA's Stardust spacecraft as it did a fly-by in January.



Can you believe it? It looks too dramatic to be true, although I'm sure it's for real. The heavily cratered surface seems different from other comets we've seen up close. Probably the image was tinkered with a bit to bring out the highlights, but it's impressive nonetheless.

So is the mission: Stardust is not just taking pictures, it has captured material from the comet's tail and is sweeping its way back to Earth. In January 2006, if all goes according to plan, the spacecraft will land gently in Utah, and scientists will begin analyzing the comet material in the lab. A great example of what wonderful science can be done without diverting all of our money into sending astronauts to Mars (sorry, couldn't help myself).

~ posted by Sean Carroll at 4:28 PM ~ link ~ ~ ~

 
Interesting and uninteresting questions about torture

There are interesting and uninteresting questions one can ask about torture. An interesting one is "Is it ever morally permissible for a regime to torture prisoners?"

I would love to answer "No", but it's a complicated question. The standard arguments in favor of torture are well known. Imagine we are in a situation of imminent peril to a very large number of people (a "ticking time bomb," literally or figuratively), and we know for sure that a certain prisoner has information that could be used to prevent the disaster, and strongly suspect that the prisoner would give up the information under torture but would not under conventional interrogation. That's a lot of conditions that must be satisfied (1. imminent danger to 2. a very large number of people, 3. knowledge that prisoner has crucial information that 4. they will not give up without torture but 5. they might give up under torture), but I would add at least one more: 6. the prisoner must, by previous actions, have forfeited even minimal personal rights, e.g. by committing some egregious crime. I don't think it's right to torture an innocent bystander who happened to overhear a terrorist plot but for some reason doesn't want to divulge the information. If all of these circumstances clearly applied, I would be willing to concede that torture would be justified. Under ordinary non-desperate conditions, I strongly believe that every person has a minimal set of rights that society has no right to violate; but under well-defined emergency conditions, the interests of the larger group can reasonably take precedence.

The problem, of course, is that such stringent conditions rarely apply. I used to be in favor of the death penalty, as I believed that there were some people who had, by their behavior, given up any right to live. I still believe that, but now I am strongly anti-death-penalty, only because I have no confidence whatsoever that our justice system can accurately determine who those people might be. Even the chance of one mistake, putting someone to death who was innocent (or even not as unforgiveably guilty as had been supposed), makes the use of the death penalty completely unpalatable. Similarly with torture -- the danger that it could be used against people who do not meet all of the above criteria is real and terrible. Of course, with the death penalty there is a straightforward alternative (life imprisonment), whereas in the shadow of a ticking time bomb the choice may not be so clear.

There are further problems, which have been widely discussed of late: specifically, the longer-term deleterious effects of being known as a country that permits torture. Breaking the prohibitions against such behavior invites similar treatment of your own citizens, not to mention general resentment among people who tend to sympathize with the tortured subjects. On the other hand, if all of the above highly restrictive conditions were actually met before torture was ever used, it would be confined to moments of such extreme danger that the attendant bad publicity would likely be an irrelevant side issue.

There are interesting blogospherical thoughts on the issue from Jack Balkin, Eugene Volokh, Kieran Healy, and Matthew Yglesias, among many others. It's very difficult, as Volokh mentions in another post, to even think rationally about these questions, as the real-life consequences are so sickening. But, as recent events have shown, we have little choice.

An example of an uninteresting question about torture would be: "Did high-level officials in the Bush administration understand how it was being used in Abu Ghraib and other Iraqi prisons?" This question is uninteresting, not because it is unimportant, but because the answer is perfectly obvious: Of course they did. Not only does it seem implausible on the face of it that widespread patterns of similar behavior spontaneously arose in the acts of a few bad apples, and not only do the infamous torture memos and other documents make clear how the administration was planning its legal justification all along, but the administration has been very open in its view that there should be essentially no restrictions on how the "war on terror" should be conducted, in any theater and by any U.S. agent. The President and his officers consider themselves to be unimpeachable agents of good in the war against evil, and will never hesitate to break a few eggs in the process of making their omelet against terror. What's been happening in Iraq is a perfectly consistent extension of well-documented policy, and there's no reason to think that it's disconnected from the orders from on high.

The only reason the administration is acting even somewhat contrite is because there were photos taken, and the images are too vivid and horrifying for anyone to admit they were part of an approved policy. Had the evidence been limited to testimony of prisoners and Amnesty International reports, the response would not have extended beyond stonewalling. Who knows what else is still going on.

Update: Never mind. Belle Waring has answered all the questions. Or unasked them, at any rate.

~ posted by Sean Carroll at 10:56 AM ~ link ~ ~ ~

 
Bloomsday

I confess that I've never read Ulysses (although Dubliners was brilliant), but I don't see why that should stop me from celebrating Bloomsday. Today is the centenary celebration of the wanderings of Leopold Bloom and Stephen Dedalus through Dublin, as recounted in James Joyce's masterpiece.

My best Bloomsday experience, believe it or not, was at an Irish pub in Paris a few years ago. (Don't be too surprised; Paris has at least thirty-eight Irish pubs, which although probably not as many as Chicago is still pretty good.) Everyone in the pub spoke English, mostly with delightful Irish accents. A group of actors visiting from Ireland took turns reading from Joyce's works, including a yeomanlike effort at Finnegan's Wake. My favorite was the reading from The Dead. An overly long excerpt:

She broke loose from him and ran to the bed and, throwing her arms across the bed-rail, hid her face. Gabriel stood stockstill for a moment in astonishment and then followed her. As he passed in the way of the cheval-glass he caught sight of himself in full length, his broad, well-filled shirt-front, the face whose expression always puzzled him when he saw it in a mirror, and his glimmering gilt-rimmed eyeglasses. He halted a few paces from her and said:

"What about the song? Why does that make you cry?"

She raised her head from her arms and dried her eyes with the back of her hand like a child. A kinder note than he had intended went into his voice.

"Why, Gretta?" he asked.

"I am thinking about a person long ago who used to sing that song."

"And who was the person long ago?" asked Gabriel, smiling.

"It was a person I used to know in Galway when I was living with my grandmother," she said.

The smile passed away from Gabriel's face. A dull anger began to gather again at the back of his mind and the dull fires of his lust began to glow angrily in his veins.

"Someone you were in love with?" he asked ironically.

"It was a young boy I used to know," she answered, "named Michael Furey. He used to sing that song, The Lass of Aughrim. He was very delicate."

Gabriel was silent. He did not wish her to think that he was interested in this delicate boy.

"I can see him so plainly," she said, after a moment. "Such eyes as he had: big, dark eyes! And such an expression in them -- an expression!"

"O, then, you are in love with him?" said Gabriel.

"I used to go out walking with him," she said, "when I was in Galway."

A thought flew across Gabriel's mind.

"Perhaps that was why you wanted to go to Galway with that Ivors girl?" he said coldly.

She looked at him and asked in surprise:

"What for?"

Her eyes made Gabriel feel awkward. He shrugged his shoulders and said:

"How do I know? To see him, perhaps."

She looked away from him along the shaft of light towards the window in silence.

"He is dead," she said at length. "He died when he was only seventeen. Isn't it a terrible thing to die so young as that?"

"What was he?" asked Gabriel, still ironically.

"He was in the gasworks," she said.

Gabriel felt humiliated by the failure of his irony and by the evocation of this figure from the dead, a boy in the gasworks. While he had been full of memories of their secret life together, full of tenderness and joy and desire, she had been comparing him in her mind with another. A shameful consciousness of his own person assailed him. He saw himself as a ludicrous figure, acting as a pennyboy for his aunts, a nervous, well-meaning sentimentalist, orating to vulgarians and idealising his own clownish lusts, the pitiable fatuous fellow he had caught a glimpse of in the mirror. Instinctively he turned his back more to the light lest she might see the shame that burned upon his forehead.

He tried to keep up his tone of cold interrogation, but his voice when he spoke was humble and indifferent.

"I suppose you were in love with this Michael Furey, Gretta," he said.

"I was great with him at that time," she said.

Her voice was veiled and sad. Gabriel, feeling now how vain it would be to try to lead her whither he had purposed, caressed one of her hands and said, also sadly:

"And what did he die of so young, Gretta? Consumption, was it?"

"I think he died for me," she answered.

~ posted by Sean Carroll at 1:46 PM ~ link ~ ~ ~

 
Left Behind again

If I were quicker, I'd be ahead of the curve. I had been planning to mention this poll about religious belief from pollingreport.com, which had been forwarded to me by a friend, but hadn't gotten around to it; now somehow everyone is all over it. (See comments from Ed Brayton, Kieran Healy, and Eugene Volokh.)

The interesting thing is, the numbers that are making people jump are those concerned with literal interpretations of the Bible: Sixty percent of American adults believe in the literal truth of the Flood, sixty-four percent in the parting of the red sea, and sixty-one percent that the world was created in six days. These are indeed alarming, as is the fact that seventy percent of adult Americans believe in Hell and the Devil. The number that is most scary to me is the biggest one: Ninety percent believe in God. To me, the belief in God is no more intellectually respectable than belief in Hell or in the Flood, or in the six-day creation. After all, the Bible is supposed to be the inspired word of God, and why would He lie? (Although even the authors of the Left Behind series agree that the part in Revelation about the sword coming out of Jesus' mouth is supposed to be symbolic.)

The amount of observational evidence for God is precisely equal to that for the Devil, the Flood, astrology, or the Easter Bunny: zero. There are plenty of a priori arguments floating around, but anyone who isn't already convinced can see that they're pretty silly. It shouldn't be any more respectable to believe in God than it is to accept the more extravagant consequences that follow from such a belief. I hate to admit it, but religious liberals who cling to a wishy-washy notion of divinity that is shaped to conform to their pre-existing beliefs seem to be less intellectually honest than the Biblical literalists. For the same reason, I find myself sympathizing with the bishops who refuse communion to openly gay couples -- of course they are wrong, but at least they are being consistent, as officers of a church that condemns homosexuality. Religious belief is a strong and meaningful stance to take on how the universe really works; one that is wildly at odds with all of our experience, but not one that lends itself to arbitrarily picking and choosing among its tenets.

~ posted by Sean Carroll at 6:50 PM ~ link ~ ~ ~

 
Sacrifice

The only interesting thing I have ever learned from Mickey Kaus' blog: the internet is spelling the death of fashion. Not that anyone should be surprised, really.

Apparently, in the good old pre-electronic-dissemination-of-information days, a new trend could sweep onto the scene and enjoy months of popularity within the safe confines of fashionista circles. Whereas today, the "derisive cackling of so many bloggers" is able to squelch revolutionary new ideas (like the fauxhawk, here fetchingly modeled by David Beckham) before they can live out their natural spans.

But I have faith in the ability of cultural institutions to adapt and thrive under challenging new conditions. The fashion vanguard will have to develop new strategies to resist the taunts of the uncultured, or even to exploit them in the service of greater hipness. What could be more cool than to not only look cutting-edge, but to be persecuted by the electronic masses at the same time? We owe a debt of gratitude to our scenester elites, who are willing to suffer the slings and arrows of faceless bloggers in order that innovative hairstyles may continue to be explored.

~ posted by Sean Carroll at 12:09 PM ~ link ~ ~ ~

 
Laws of nature

Hey, this is my 100th post. Congratulations, in a sense, to me.

The Poor Man points to a post by Brad DeLong, which in turn relates an email account of a talk by Seymour Hersh here at the University of Chicago. The talk was about the torture at Abu Ghraib, giving the very vivid impression that things were much worse than we've been told thus far. DeLong says "If what it reports is true, then once again it looks like the Bush administration is worse than I had imagined--even though I thought I had taken account of the fact that the Bush administration is always worse than one imagines." An inspired formulation, very reminiscent of Hofstadter's Law. I therefore propose DeLong's Law:

The Bush Administration is always worse than one imagines, even when taking into account DeLong's Law.

It's useful to keep in mind, even if it's no real help.

Update: Actually, DeLong has a few other laws (here, here, here), so I'm not being original.

~ posted by Sean Carroll at 12:53 PM ~ link ~ ~ ~

 
Finals

The NBA Finals are underway, and like many expatriate Philadelphians I am watching with mixed feelings. On the one hand you have the Lakers, one of those dominant teams overflowing with arrogant superstars who are impossible to like, not to mention the frequency with which the franchise has beaten up on my beloved Sixers in NBA finals past (2001, 1982, 1980, 1954, and 1950 -- the last two in the Sixers earlier incarnation as the Syracuse Nationals, and the Lakers earlier home in Minneapolis). So under ordinary circumstances it would be easy to root for the Detroit Pistons, plucky underdogs with hard-working overachievers like Rip Hamilton and Ben Wallace. The complicating factor is coach Larry Brown, who for the previous six years had been coaching the Sixers. Brown resurrected the franchise from the doldrums, leading us to the Finals in 2001, only to jump ship after realizing that a series of bad deals he himself had made had left the team stuck in mediocrity. Adding everything up, I still have to root for the Pistons, who are now up two games to one after completely dismantling the Lakers last night. Announcer Al Michaels, assuming like the rest of the media that the Pistons have no real chance to win the series, was trying to be complimentary halfway through the second half when he started to say that the Pistons had at least guaranteed that the series would go six games -- before catching himself as he realized 1) how condescending that sounded and 2) that the series is by no means guaranteed to go six games, the Pistons could very well win it in five.

The playoffs have been very entertaining thus far, but ESPN decided to spice things up by having a round-table discussion with Larry Bird, Magic Johnson, and rookies Carmelo Anthony and LeBron James. James and Anthony are both only 19 years old, but it was the wise old heads Bird and Magic that said the stupid things that discussions like this always seem to generate. In particular, Bird thinks that the NBA needs more white superstars to get people interested in the league. (And Magic immediately agreed with him.) He's going to get in trouble for that, obviously. Hopefully the criticism will point out that Bird is being clueless, not racist -- although in the context of sports it's not always a useful distinction to draw. The NBA is about 77% African-American, and has been for a while. As people will quickly point out, race hasn't been an obstacle to popularity for Michael Jordan, Shaquille O'Neal, Allen Iverson, and countless others. But while Bird emphasizes that blacks are the best athletes in the world etc etc, by claiming the you need white stars to interest a white audience he injects the race issue where it just isn't as important as he supposes. What the NBA really needs is a minor-league system, so that youngsters who skip college can get trained in how to play the game, including occasionally making a fifteen-footer and executing a pick and roll (or even a simple entry pass). If the quality of the product is there, the fans will follow.

Note added in proof: As this article was being prepared, we became aware of similar work by Uncertain Principles.

~ posted by Sean Carroll at 12:29 PM ~ link ~ ~ ~

 
He ain't heavy, he's my boson

It looks like the Higgs boson, the only part of the Standard Model of particle physics that has not yet been directly detected, might be heavier than we thought, and correspondingly even more difficult to detect. This, anyway, is the claim of a new analysis from the D0 experiment, one of the two (along with CDF) large general-purpose detectors at the Tevatron particle accelerator at Fermilab. (See also comments from David Harris.) What they've actually done is to improve their measurement of the mass of the top quark, the penultimate particle of the Standard Model, discovered at Fermilab in 1995. Through the miracle of quantum mechanics, the properties of all the different particles of the Standard Model come into calculating the rates of various interactions; so given what we know about certain interactions, we can infer the mass of the Higgs if we very accurately know the mass of the top.

Of course, there are a lot of assumptions that go into such an inference. Personally, I tend not to trust them; the history of physicists predicting the mass of particles like the top and the Higgs is not filled with spectacular successes. Usually we don't come up with a convincing explanation until after we've finally measured it.

Fermilab's Tevatron is currently the highest-energy particle accelerator in the world, and two of its major goals are to find the Higgs and to find something completely outside the Standard Model, such as supersymmetry or extra dimensions. Competition is on its way, from the Large Hadron Collider at CERN in Geneva, which is scheduled to turn on in 2007. The LHC will have a significantly higher energy than the Tevatron, and should easily be able to detect something new and interesting, whatever that may be. There is a "nightmare scenario" in which the LHC discovers the Standard-Model Higgs and nothing else, giving us no clues about new physics; I'll put long odds against it, though.

Particle physics is desperate for an experimental discovery that isn't already accommodated by the Standard Model; no particle accelerator has given us such a surprise since, oh, the mid-Seventies. This drought has caused a great deal of anxiety and hand-wringing, but it is certainly the exception rather than the rule; more often in physics the experiments are running far ahead of the theories, and we're scrambling to explain all of the new phenomena being uncovered. I suspect we'll be rapidly back into such a phase once the LHC comes online, if not sooner. (For any physics undergraduates or beginning graduate students out there who are worried about job prospects and wondering what field to go into, my advice would be particle phenomenology. In the five-year timescale to get a Ph.D., the field will go from being listless and anticipatory to rambunctious and contemporary, and good young people will be in huge demand.)

~ posted by Sean Carroll at 11:33 AM ~ link ~ ~ ~

 
Media

Following up on my story about switching from a computer-projected talk to a blackboard talk at the last minute, Chad Orzel hashes out the pros and cons of blackboard vs. computer vs. overhead transparencies. (I talk about "computer" presentations rather than "PowerPoint" because I actually use StarOffice, which has a better equation editor and also is free.) Michael Nielsen and Doron Zeilberger give their takes as well.

This is the kind of thing scientists talk about when they're not uncovering the mysteries of the universe. Computer presentations have become the standard in many fields, although there is a substantial wailing about the attendant impersonality (and often incomprehensibility) of the result. Edward Tufte has written a celebrated anti-PowerPoint screed, even holding the conventions of that particular medium partially responsible for the Challenger disaster (apparently NASA engineers gave a PowerPoint presentation on the problems during the flight that served to camouflage rather than highlight the potential dangers). As Chad points out, it's one thing to stand at the blackboard and talk about theoretical ideas involving equations and some simplistic figures, but very different if you are trying to present data. Personally I will use the computer if I'm giving a colloquium or conference talk, and prefer the blackboard if I'm giving a more specialized seminar. This particular conference was small and specialized enough that using the blackboard made sense. It certainly slows down the presentation, which is almost always good. In principle a sufficiently talented speaker can go at the right pace and be perfectly understandable while using slides, but in practice the chalk tends to force you to go at a reasonable pace and leave out superfluous details that you're tempted to include on your slides.

What scientists will never understand is why folks in the humanities will literally read their papers -- just stand up there, manuscript in hand (or on podium), and read each word verbatim, even if everyone in the audience has a transcript right in front of them. What is the point of that? The first time I saw it I was baffled, and I still haven't quite figured it out. I tried it myself when I gave a talk at a humanities conference, but to be honest I just couldn't do it -- I kept extemporizing, so much so that none of my sentences appeared just as they were on the page.

It's good to be open-minded about the practices of different disciplines, and for a long time I excused this weird habit by figuring that humanities talks had to be extremely precise with their language, with every word chosen carefully after hours of late-night concentration. But I've come to believe that there's really no excuse. The quality of presentation of a talk that is directly read off the manuscript will just never be as good as one that is given from notes or an outline. Whether or not the precision of the writing seems to be of utmost importance, it's not as if the listeners are going to remember the talk word-for-word, so I think an engaging presentation of the general ideas will always be more effective than a stodgy reading of perfect precision. Can we scientists (who, more often than not, give awful talks, but for different reasons) somehow persuade our less quantitative colleagues to free themselves from the prison of the printed page?

~ posted by Sean Carroll at 8:24 PM ~ link ~ ~ ~

 
Hyperspace, Superspace, Theory Space, and Outer Space

Back from sunny, cicada-ridden Baltimore and the conference mentioned previously. It was a small, fun conference; the idea was to keep it simple and informal, so that people could spend time talking to each other and perhaps even get some work done. My talk was scheduled at the very end, so I didn't get any work done, but split my time between socializing and making an electronic version of the talk (which I had given previously, but only on the blackboard at seminars). In the end it was for naught, as I complained about having to make the electronic version and received a chorus of requests to just go ahead and give the blackboard talk, which I did. It went pretty well, so we'll see what kind of reaction the paper gets.

The participants were all theorists working on particle physics, string theory, and cosmology -- overlapping fields with a lot of activity and connections these days. Some of the memorable talks:

• Gia Dvali talked about modified gravity in cosmology (as I blogged about recently).
• Angela Olinto gave a nice review of ultra-high-energy cosmic rays and neutrino experiments.
• Shamit Kachru talked about compactifying extra dimensions in string theory and the string-theory "landscape" of possible vacua.
• Alex Szalay gave an interesting talk on the huge data sets appearing in modern astrophysics -- we're moving from terabytes to petabytes, leading to files that would take years just to search using ordinary methods.
• Ann Nelson and Neil Weiner both gave talks on interactions in the dark sector (undeterred by my skepticism).
• Eva Silverstein talked about inflation from nontrivial kinetic terms for string-theory moduli, including potentially observable signals (!) of non-Gaussianity in the cosmic microwave background.
• Jacob Bekenstein talked about modified gravity as a replacement for dark matter.
• Nima Arkani-Hamed talked about "ghost" fields as dark energy.
• Marc Kamionkowski talked about dark matter that is neutral, but couples to electromagnetism through a dipole moment.
• Hitoshi Murayama talked about the minimal possible model that is consistent with all of our current data.
• Even the summary talk, by Joe Lykken, was fantastic.

You get the idea, I hope: lots of interesting ideas, bumping up against new constraints from experiments, bringing together fields that weren't talking to each other just a little while ago (e.g., when I was in grad school). It's an exciting time.

~ posted by Sean Carroll at 10:53 PM ~ link ~ ~ ~

 
Charm City

I'll be away for the next few days, attending this conference at Johns Hopkins. I've been trying to curtail my excessive traveling, but this workshop seems to have a lot of interesting speakers; I'll report back if any startling new ideas emerge. I'll be giving my soon-to-be-famous talk on how inflation explains the low entropy of the early universe. If only I could find time to write the actual paper, we could put Boltzmann's ghost to rest.

~ posted by Sean Carroll at 1:46 PM ~ link ~ ~ ~

 
A time to reap

We're on a quarter system here at Chicago, which means we don't start until October (good) but we keep going until the beginning of June (bad). Which is to say, I have just handed out the take-home final exam for my Spacetime and Black Holes class, an undergraduate introduction to general relativity. It has been a great class, full of curious and enthusiastic students (at least two of which, Maire and Colin, have blogs; feel free to let me know if anyone else does).

Let me see, I've been alive for thirty-seven years, thirty-two of which have involved spending much of my time in an educational institution of one sort or another, from nursery school to being a professor. And still, I have to admit, I love the rhythms of the school year, from the fresh fall days when the campus comes back to life with arriving students, to the slogging twilight of the winter quarter, to the cusp of summer when another year has been successfully negotiated. Why would anyone want to leave to go to the real world? But that, of course, is the downside: so many people at any school are there just temporarily, whether it's students or postdocs or, when things don't turn out as we hope, assistant professors. Some of the UofC students at Crescat Sententia are graduating seniors, and are grumbling wistfully (sounds impossible, but it's true) about the impending end of their days here. It's equally bittersweet to be on the other side, as students who you've seen working and growing in an impossibly short time prepare to take off for their next set of challenges.

So, congratulations to all the graduating seniors, not to mention graduate students about to get their Ph.D.'s and postdocs moving on to other jobs. For the students, be sure to enjoy the ceremony, which can seem anticlimactic if you don't take time to reflect on what you've accomplished. It's a big deal.

~ posted by Sean Carroll at 12:37 PM ~ link ~ ~ ~

 
Robots in space

Looks like the idea of sending robots to repair Hubble is gaining some steam. They wouldn't be able to do everything you could do with a servicing mission, but they could install new instruments and gyros to keep the telescope running for quite a while longer. (Or not -- if it's deemed unfeasible, they might use a robot just to prepare the satellite for re-entry into the atmosphere.) It will be up to the engineers to build robots that can reliably do the job, which isn't easy; but my bet is that it can be done. This challenge has actually energized a lot of folks at NASA, and fixing the Space Telescope is a goal everyone can agree on.

~ posted by Sean Carroll at 3:29 PM ~ link ~ ~ ~

 
Geography

Chicago is a fantastic city in many ways; at some point I should do a series of posts on why this is the greatest city in the world to live in. One reason, believe it or not, is geography. In some respects, it's not good to live on a large plain in the middle of a large continent; there are no mountains nearby to go climbing, and with no nearby oceans the weather can get pretty dramatic. (I once read that there are only three metropolitan areas with greater than five million people in which the temperatures regularly reached over 100 degrees F in the summer and below zero in the winter: Beijing, Moscow, and Chicago.) But there is an important benefit as well: it's much harder to sneak up on an inland city with a nuclear weapon than it would be if we were on one of the coasts.

To be sure, Chicago is only about the fourth-ranked U.S. target that one would choose for a dramatic blowing-up; New York, Los Angeles, and Washington D.C. have to be ahead of us on the list. That, coupled with the difficulty of smuggling a nuclear weapon all the way into the interior, makes it seem relatively safe here. If I lived in one of those three coastal cities, I wouldn't be nearly as sanguine. It's one of those things we don't like to talk about, but the chances of a terrorist group cobbling together the technology and raw materials for making a bomb have to be appreciable, given the half-hearted efforts that have been made to quarantine both resources and know-how thus far. (Not only have we gone quite easy on people who are known to share nuclear secrets, but our violations of the test-ban treaty and plans to build "small" tactical nuclear weapons have created a climate in which other countries do not feel encouraged to give up their own nuclear programs. Not to mention the fact that successfully building a bomb would be excellent proof against getting invaded.)

Mutually Assured Destruction, shaky as it was as a defensive doctrine under the best of circumstances, is nearly useless against terrorist organizations. There's no way of guaranteeing we would even be able to pinpoint the true culprits, nor to counterattack if we could. If terrorists somehow get the bomb, they're very likely to use it.

So what are the chances of a nuclear bomb being detonated in a U.S. city sometime in the next fifty years? One percent? Ten percent? These seem like reasonable numbers to me. What to do about it, I'm less sure.

Of course, risk analysis is notoriously difficult, and people tend to do a terrible job even when it's easy. How many people would evacuate L.A. if scientists could guarantee that there was a 20% chance of a devastating earthquake (millions dead, city in ruins) in the next twenty years? I suspect not many; when the danger is so diffuse, it's hard to take the tangible steps necessary to avoid it.

It was good to hear that Kerry is putting nuclear proliferation high on his list of foreign-policy priorities. (Even if he did choose to wear an old Monday Night Football blazer while doing so. Doesn't he have wardrobe consultants on staff?) I don't know how effective we can be, but doing everything conceivable to prevent a nuclear weapon from exploding in one of our cities seems like an easy priority to agree on.

~ posted by Sean Carroll at 9:18 PM ~ link ~ ~ ~