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Uncertain Principles

Physics, Politics, Pop Culture

Wednesday, July 31, 2002

Everything I Need to Know I Learned From Watching Spiderman

There's been a fair bit of blogging today about the Keith Olbermann article in Salon, where he lays into Ann Coulter and the media in general for ignoring early warnings about terrorism in favor of more glamorous topics like Bill Clinton's sex life. Olbermann's always been a little erratic, but when he's on, he's very good, and he's mostly on here.

What struck me most was this passage, though:

But I tend to think Rose is a lot closer to understanding what he did, and why people hold it against him, than is Ann Coulter. Since Sept. 11 she has been a veritable out-of-control firehose of venom, whipping around crazily, streaming invective wherever she happens to point. I wouldn't be so disturbed if I sensed there was a glimmer of irony in this new book of hers, some quick wink of Buckner-like acknowledgment that "Slander" might be read not as a title, but as a description of the contents.

I had exactly the same thought ("At least she went for truth in advertising") earlier today, when I saw her book in a store while I was running other errands. Of course, even there, she's wrong, having forgotten the words of J. Jonah Jameson: "Slander is spoken. In print, it's libel."

Posted at 4:12 PM | link | 3 comments

The Drexler Continuum

Somewhat ironically, my earlier post about cryonics was prompted in part by one of the explanations offered for how future doctors would be able to resuscitate frozen patients-- that "nanomachines" would be used to repair the damage caused by freezing on a cell-by-cell basis. It's ironic because, while this was an explanation offered to make cryonics seem more plausible, if anything it increased my skepticism on the subject. "Nanotechnology" is the "nuclear" of the new millennium-- it's claimed as the mechanism for all sorts of pie-in-the-sky bits of technological wizardry that we're assured will certainly be coming any day now, in just the same way that an earlier generation of futurists thought nuclear power would be the cure for all our energy woes. Invoking nanotechnology, particularly the extravagant claims of the Drexler branch of the field, as the mechanism for some future technological wonder draws an almost reflexive "Yeah, right..." from me.

That's not to say that nanotechnology is cold fusion writ small, just that it's rare for any technology to really follow exactly the trajectory suggested by its most fervent proponents. I think we'll get wonderful new gadgets out of the study of very small machines (a recent Physics Today article (sorry, no link) points out that we've already got some), I just don't really believe that they'll be based on tiny robots constructing useful devices atom by atom, or little free-roaming von Neumann machines in the bloodstream repairing damage on the cellular level. Those claims have the same sort ring of True Belief as past claims of "electricity too cheap to meter," the sound of people who have made the leap from "wouldn't it be cool if we could do this?" to "we'll definitely be able to do this, and won't that be cool?" without passing through the intervening layers of careful investigation of the real potential of a technology.

Science and technology move forward, but we're really, really bad at guessing the directions they'll take, or even what problems will prove difficult. I don't read a whole lot of "futurist" books, but I do read a good deal of what booksellers term "genre fiction," mostly science fiction and fantasy. The "hard SF" sub-genre fairly closely tracks the current conventional wisdom about the future of technology-- essentially, the past hundred-odd years of science fiction, provide a very nice record of where people thought we were headed, dressed up a bit with noble, selfless, and hyper-competent techie heroes and the women who love them, and the occasional sinister alien menace. It's sort of interesting to look back over the history of the field, and see what people thought the future would be like, what they got right, and what they got wrong.

There's a fair amount of back-slapping in the genre over the successes various authors have had in predicting the future-- Jules Verne predicted submarines, Arthur C. Clarke predicted communications satellites, etc.-- but the successes are not nearly so interesting as the failures (especially since many of the successes require you to bend and twist the original sources to see the success...). It's sort of trite to complain about the lack of flying cars, and anyway William Gibson nailed the Gernsback era better than I ever could, but there are all sorts of little things that people missed. Clarke predicted communications satellites, but I can't think of anyone off the top of my head who really got cell phones, or the Global Positioning System before they existed in the real world. Nobody really picked up on the ubiquity of personal computing until it was a fait accompli, and those authors who did pick up on the idea of the Internet mostly missed its real impact, which has been not so much at the level of the giant multinational corporation, but down at the slob-on-the-street level, providing unparalleled access to information, and even dopey things like online shopping. I was reading a Henry Kuttner short from the early Fifties a month or so ago that even failed to pick up the cultural implications of tv...

Lasers are another decent example, and one near to my heart. At the time of its invention, the laser was famously deemed "a solution in search of a problem." Forty-odd years later, it's the solution to all kinds of problems, many of which the original inventors wouldn't've recognized as problems in the first place. There are a few obvious applications, like the various uses of lasers for cutting metal, and some scientific research, but there's a huge spectrum of ridiculously mundane uses for the things that no-one would've predicted-- telecommunications, CD players, grocery store scanners, all the way down to the laser pointers used in giving talks. And yet we still don't have the laser death weapons that everybody assumed we'd build.

As a general rule, it seems that technological forecasters do a reasonably good job of predicting changes on a very coarse scale, in terms of seeing a use for a technology on the level of governments or huge corporations. For a genre that relies so heavily on rugged individualists for characters, though, SF authors are absolutely miserable at predicting the effects of technology on an individual level. Bruce Sterling notes the difficulty by saying "the street has its own uses for things," which is a memorable phrase, if a little too stylishly grungy to really be accurate-- the predictions don't fail because authors fail to take into account the uses small-time hustlers and petty crooks find for technology, they fail because the authors fail to pick up the uses found by the comfortable members of the middle class.

Another interesting aspect of the process is the way new concepts tend to sweep in, take over everything, and then trickle on out when the real-world technology fails to keep up. Space travel has been a staple of the genre, off and on, for years, often combined with a wildly optimistic view of the technology needed-- there's something incredibly charming about a book like Mission of Gravity, where the author assumes that we'll reach the distant stars while still doing calculations with slide rules. People continue to cling to the idea of space colonization, but the popularity of space stories is nowhere near what it used to be, as it's gradually become clear that space travel is expensive and fairly impractical, and there isn't a really compelling reason to send humans out into space at the moment. Nuclear power is another one-- I recall reading a number of stories from the distant past where people tooled around in nuclear (fission) powered cars and the like, a dream that ran afoul of the nasty properties of nuclear waste (which are over-sold, but still pretty bad). Fusion's another staple, though commercial fusion power remains twenty years off, and is expected to remain twenty years off for the next twenty years or so. Computers and "virtual reality" had a pretty good run for a while as the darlings of futurists everywhere, with half the writers in America apparently convinced that we'd all be spending most of our time in fantasy worlds by now, but that's tailed off as well.

The current reigning champions for Hot Technologies, in science fiction and out, are biotech and nanotech-- twenty years from now, the current line goes, we'll either be replacing our failing organs with cloned replicas or staving off organ failure by means of miniature repair robots in our bloodstream. Given the dubious history of technological prognostication, though, it's hard to really credit these predictions more than the "colonize the Moon with slide rules and mainframes" visions of the past. The vision being pushed, particularly for nanotechnology, is just a little too rosy to be believed, and the problems being brushed aside to get to the imagined marvels of the future loom larger than the techno-optimists would like to believe. The "atom-by-atom" construction robots are a profoundly classical idea (I pick up this atom and put it here, then that atom, which goes there) that would need to function in the microscopic world of quantum mechanics, while the "cellular repair robots" vision tends to rely on a fairly unrealistic extrapolation of Moore's Law (about which more later) to give the robots the necessary processing power. I don't see either of those obstacles being overcome easily.

Which is not to say that nothing worthwhile can come from research into nanotechnology and biotechnology. The failure of past predictions to pan out as advertised doesn't mean that we haven't had marvellous technological advances over the past several decades-- cell phones, the Internet, DNA analysis, GPS navigation, ubiquitous computing (my car has more computing power than the Apollo spacecraft did), and so on. A person from 1950 who managed to pop up in 2002 without passing through the intervening decades would be awed by some of the things we take for granted.

Similarly, the likely failure of current predictions doesn't mean we won't get wonderful things out of the trendy technologies of the moment. They're just not likely to be the things we're told we'll get now.

Posted at 9:30 AM | link | 10 comments

Tuesday, July 30, 2002

Yep. Still Green.

There were summer student research talks at lunch today. During one of the talks, by a biology major, I noticed a URL in a photo credit, which led me to: The MossCam Project. Yes, it's just what it sounds like. It's a webcam pointed at a mossy rock somewhere in California.

Which is not to say that there isn't wonderful science to be done in studying the behavior of mosses growing on rocks in California. But there's something inescapably ridiculous about a site which contains the text "click here to view quicktime movie of moss."

Posted at 8:22 PM | link | 1 comment

Blinded by the Snake

An additional radio note, following on yesterday's post.

One thing I've noticed is that every radio station seems to have at least one signature song that they play again and again, completely out of proportion to the actual popularity of the song. I'm not talking about the latest hits, here-- of course the newest smash from Puddle of Creed is going to get played every hour, like it or not-- but older, minor hits from yesteryear. For instance, somebody at WHFS back in the day had a thing for Robyn Hitchcock, and used to play that "Balloon Man" song at least once a day.

One of the many failings of the Clear Channel near-monopoly is that this gets extended over multiple stations. Between the "Adult Contemporary" station and the "Classic Rock" station, I've heard Manfred Mann doing "Blinded by the Light" more times in the past year than in the preceding thirty. Driving around the other day, I heard it on one station, changed the station to avoid a commercial break, and heard it again on the other. I can't quite figure this out-- it's a decent enough song, though it leaves out half of Springsteen's lyrics, and it was a hit, but it doesn't really rate daily airplay on two stations in the same market. (On the subject of this song, there is a page of amusing guesses as to what, exactly, Mann is singing in the chorus, though some of those just have to be made up for comedic effect...)

The strangest by far, though, is the 80's station. Their signature tune, for no reason I can fathom, is "Union of the Snake" by Duran Duran. Now, I know the 80's. I grew up in the 80's, and while I was never victimized by 80's fashion in the same way as the people the Poor Man talks about, I nodded in recognition through that whole piece.

Back in the 80's, my 80's, every girl in the ninth grade had the screaming thigh sweats for Simon Le Bon. I heard more effusive nonsense about how wonderful Duran Duran was than pubescent male should ever have to endure. And not once did any of those girls speak of their admiration for "Union of the Snake." I can't honestly say that I was even aware, back in the 80's, that they had recorded a song called "Union of the Snake", though I did make an effort to avoid knowing anything at all about Duran Duran.

Who likes this song? What thin-tie-and-kerchief wearing freak is choosing songs for this station? Couldn't we drop this song from the playlist, and replace it with something more pleasant, like, say, four minute's worth of Emergency Broadcast System testing?

Posted at 8:55 AM | link | 9 comments

Internet Anaconda

Here's a boycott I might be able to get behind: Matthew Yglesias is following Atrios's lead, and going "Sullivan Free" for a while.

Well, actually, I'm half tempted to attempt to pick up the Sully-bashing slack, because he does piss me off (see previous entry). But I don't really need the extra aggravation, and Kate certainly doesn't (she's taking the Bar today and tomorrow, and doesn't need to listen to me rant about what a pinhead Sullivan is...). So I'm in.

Hey, Matt, maybe you can use this as a springboard to becoming the liberal Instapundit...

Posted at 8:23 AM | link | no comments

Monday, July 29, 2002

Return of the Pee-Wee Herman Defense

Andrew Sullivan gets huffy about the recent William Safire "blog" piece, wherein the noted language maven wrote:

"Will the blogs kill old media?'' asked Newsweek, an old-media publication, perhaps a little worried about this disintermediation leading to an invasion of alien ad-snatchers. My answer is no; gossips like an old-fashioned party line, but most information seekers and opinion junkies will go for reliable old media in zingy new digital clothes.

Sullivan's response is to deride the reliability of "old media" by trotting out a list of Safrie's errors over the years:

Last February, Safire conceded he had misplaced the context of a quotation by Shakespeare, miscalculated the odds of several politicos, misunderstood the real meaning of "parlous," got the name of a Conan Doyle watchdog wrong, and so on. Nothing wrong with that, and his corrections column was gracious, if far less prompt than most bloggers'.

Of course, to his credit, and unlike some bloggers, Safire actually tells people when he makes a correction to something he wrote...

Is it just me, or is there a little "I know you are, but what am I?" element to this swipe, coming as it does on the heels of Sullivan getting "fact-checked" on his surreptitious editing?

Posted at 1:42 PM | link | no comments

Radio Free Wasteland

In many ways, I was badly spoiled by going to grad school in the DC area. There was decent (not great, but decent) public transportation to get around the city, all sorts of cultural stuff to see and do, a great selection of restaurants where even a Starving Grad Student could afford to eat, and, of course, the Brickskeller where I could blow the money I saved by buying cheap food on expensive beer brewed by Trappist monks in Belgium.

I really miss the restaurants-- there are some pretty good places in the Albany area, but nothing like the variety I had available when I lived in (Don't Go Back to) Rockville, MD-- from my house, it was an easy walk to five of the restaurant on the Cheap Eats list, for chili, Caribbean food, Indian food, or two different kinds of Vietnamese. Another half-dozen were a short drive away. There's just no beating that.

One of the other features I've found myself missing in recent years is the decent selection of radio I had available, particularly WHFS, which was then in its heyday. That was a great station-- they played a good variety of stuff (provided you liked alternarock sorts of things), from Bob Marley to Nirvana, to the occasional William Shatner record late at night, they had a morning show which consisted primarily of music, interrupted occasionally by actual news reports (and the Daily Feed, which was a riot), and the DJ's were amusing but relatively unobtrusive.

Now, I'm living in the Great Radio Desert of upstate New York. There's the inescapable classic rock station, and the candy-ass Adult Contemporary ("the best of the 70's, 80's, 90's and today!") station. There's turgid New Metal touted as "Your New Music Alternative", or turgid New Metal with occasional interludes of decent music, touted as "The Real Alternative" (the only one of these stations not owned by Clear Channel). The one station on the dial that's not depressing for being tediously predictable is the Eighties station, which is depressing because it makes me feel old. And, really, didn't Poison get enough airplay during the Eighties? Can't we please have mercy on the ears of future generations?

All of these stations feature Morning Shows which are Zany to a greater or lesser degree-- unlistenably so in the case of the Classic Rock station-- and make me want to find the station and throttle the chirpy morons they're subjecting me to. (Typical example of a shameful DJ moment: in a story about the National Spelling Bee a month or two back, one of the morning show twits was giggling over the fact that a previous winner had had to spell a word that he pronounced "defecation," though he admitted that he would've gotten it wrong "because of the silent 'i' in there." The word? "Deification.") None of them get far beyond a playlist of maybe three dozen songs.

The lack of decent radio is exceptionally irritating to me because I like to have music playing more or less continually. Bruce Baugh describes the basic idea pretty well: "I have music on nearly all the time when I'm awake and not doing some specific other thing that generates sound. I like it, and it helps keep the flow of my thoughts ordered; otherwise my time sense starts drifting badly." Without music as background noise, I lose focus, and get distracted by other incidental noises that would be covered by the music. Silence drives me nuts.

(Of course, my preference for a constant personal soundtrack drives Kate nuts... You can't win 'em all...)

At home, I can get around this problem by listening to my MP3 collection (yes, I downloaded stuff from Napster, back when it was a going concern, including the Mojo Nixon cover of "Girlfriend in a Coma" that's been stuck in my head all morning...), or throwing a bunch of CD's in on shuffle play. This isn't that satisfying, though, as I like hearing new stuff from time to time. A slightly better option that I've started using recently is the "Digital Music" feature of my digital cable-- I've got umpteen different specialized music feeds via the tv, and they play a pretty good range of stuff.

Neither of these really help me at work, though. In my office, I'm pretty much stuck with the radio, thanks to my lemon of a desktop computer, which doesn't deal well with streaming audio. In the lab, though, I've found a better solution, or, rather, the student who's working with me for the summer has found a solution. It's one of the handful of Web radio stations that hasn't been driven out of business by the ridiculous royalty policy bought lobbied for by the record industry, operating out of Seattle.

It appears to be some sort of public station, as they don't do commercials, and it's everything I'd like a radio station to be (save "in the same time zone"-- it's very disconcerting to hear the DJ's announcing times that are three hours behind). They play a great variety of stuff, from pop-punk to bluesy folk-rock, they hardly ever repeat songs, and the DJ's are calm, soft-spoken, and knowledgeable. They play new stuff, stuff by artists I've never heard of, and material by local bands I'll probably never hear of again. It's a really good station, probably even better than WHFS at its peak (sadly, on my last visit to DC, I found that WHFS, too, has been sucked into the Zany Morning Show swamp of big conglomerate suckitude...)

I'm not much for the anti-corporate, anti-globalization movement-- I think their intentions are good, but they're hopelessly idealistic and naive-- and the "information wants to be free" arguments of Open Source zealots also fail to convince me (I like the response attributed to Bruce Sterling-- "Information wants you to give me a dollar."). I have the same reflexive and contrary reaction to people who assume that all corporations are Evil as I do to people who assume all unions are Evil.

But, when confronted with the contrast between KEXP's web broadcasts and the homogenous crap spewed by the Clear Channel clones available locally... Well, it's hard to think of a better argument in favor of utterly destroying Clear Channel and the RIAA.

Posted at 12:09 PM | link | 5 comments

Sunday, July 28, 2002

Pascal's Wager On Ice

The NZ Bear post I referenced earlier talking about the barriers to "once a week" blogging missed one of the biggest obstacles, because it's really not a technological problem: If you only post once a week, or even once a day, by the time you get around to putting your thoughts on an issue up on the web, everybody else is sick of talking about it, and nobody wants to read a late entry into the fray, however insightful it may be.

This is one of the biggest problems I have with the way I'm running this weblog, and it's going to strike again, here. Last week, in the wake of the Ted Williams story, there was a discussion of cryonics issues over in Bruce Baugh's comments section. I posted one or two things there, and had other comments to make about cryonics and the larger issues of scientific progress, but other things were in the queue, and I'm only getting around to it now. Hopefully, I'll manage to blunder into one or two interesting statements, and get a few people to read this, but I suspect most people who were participating in that discussion have long since moved on to other ideas.

The central argument of cryonics boosters, exemplified by Rand Simberg, is that the forward march of technology is inexorable, and all the ills which presently afflict the human body will be curable in the future. Therefore, you should definitely have yourself frozen upon your "death," even though we really don't have a good idea how to freeze and revive a person, because at some point in the future, we will know..

This level of techno-optimism is sort of charming, but really, the whole thing amounts to a Pascal's Wager argument. Actually, it's worse than that-- it's four simultaneous wagers. By opting to be frozen, you're betting your life on the propositions that:

  1. Future medical technology will be able to cure what's killing you,
  2. Future medical technology will be able to freeze and revive human beings,
  3. Future medical technology will be able to repair any damage done in today's imperfect freezing processes, and
  4. Someone in the future will actually care enough to bother thawing you out.

These are all dubious propositions. Cryo-boosters tend to shrug them all off (well, OK, they generally only deal with the first three) by invoking the wonders of technology. Technology, they assume, will advance without limit ("Moore's Law" is often invoked, but that's a rant for a different day)-- some even suggest that nanomachines will be used to repair freezing damage on a cell-by-cell basis.

I don't buy it-- forecasting technological progress is a fool's game. I can readily believe some elements of the above list, but not the whole package.

To see the problems with wagers 1) and 3), consider the case of someone who died of a progressive, degenerative neurological disease-- Alzheimer's, say, or Parkinson's, or maybe Lou Gehrig's Disease. I can readily believe that future technology will be able to prevent these conditions, or halt their progress, but reversing the process? Those diseases (in my pop-science level of understanding, at least-- corrections from actual biologists and doctors are welcome) cause a steady degeneration of brain tissue, a destruction of neurons, and more importantly, the inter-connections between neurons. And as Charles Murtaugh rightly points out, "a mind is more than a bunch of neurons, it's also the connections between them. Those connections constitute information, which if lost during freezing and thawing becomes irretrievable." Reversing the damage caused by a degenerative disease would require knowing what the brain looked like beforehand, in detail-- what cells were where, and which cells connected to which other cells. Even a cell-by-cell reconstruction by nanomachines would require a blueprint to work from-- every body is subtly different, and every brain is subtly different, and I doubt it's possible to just construct a "generic brain" for someone and have them wake up the same person they were before the brain damage, or before they were frozen.

And this is exactly the sort of thing you're talking about when you invoke cell-by-cell repair of the damage done in the freezing process. Reconstructing the sort of massive cell damage Rand Simberg so blithely brushes off will require essentially this sort of cell-by-cell repair of all the cells and inter-connections in the brain. Doing that without a very clear idea of what the brain looked like before it was dunked in liquid nitrogen and still managing to end up with a reasonable facsimile of what you started with, strikes me as highly improbable. How important the exact cell structure really is, and what the consequences of an imperfect repair would be remain open questions, but these are not trivial issues to be brushed aside without a pause for thought.

There may well turn out to be a way to freeze people and thaw them back out without doing significant and irreparable damage. There may even be a way to limit the damage to a level that can be repaired, or to store a detailed brain map to allow the hypothetical nanomachines to repair the damage. But people who are frozen today, when even the ardent supporters of cryonics basically admit that we don't really know what we're doing, are unlikely to ever wake up in the golden future of their dreams. Technology can do wonderful things, but the information lost when interconnections in the brain are destroyed by disease or freezing is not the sort of thing you can pluck back out of the air, and I don't see how you can repair a brain without it.

The fourth point is also a non-trivial one. Given the level of culture shock that would be involved, it's something of a mystery to me why anyone in a future society would even bother to thaw out someone frozen today. It seems unlikely that people of today would have much to offer to a future society with technology advanced enough to thaw them out, save as some sort of historical curiosity, or lab specimen, which isn't much of a life. You're pretty much stuck hoping that future humans are exceptionally altruistic, or devout libertarians bound by the sanctity of a contract signed today. I don't think I like those odds, either.

This is, at least, a purer version of Pascal's Wager than the original. There's no "many gods" counter-argument that I can see-- the choice is really a binary one between oblivion and a life in the future, with no other options. If the four wagers happen to fall out in your favor, then you win big; if not, well, you're dead anyway. But it's important to recognize cryonics (at least in its present form) for the gamble that it is.

Posted at 1:39 PM | link | 1 comment

Context is Everything

I've been sort of shorting the "pop culture" content of this weblog recently, but here's a pop-culture item:

It was my turn to do the wash this week, and on my way over to the laundromat, I caught the very tail end of one of the umpteen "Weekly Top N" shows that run on Sunday mornings. The top spot on this particular show was Eminem's "Without Me." Now, I'm not the biggest rap fan you'll find, but it's a catchy tune, and the kid does have a way with a rhyme, even if he is an obnoxious little punk. So I left it on.

This being a nationally syndicated show, it was a censored version of the song, and censored to match the candy-ass sensibilities of some Midwesterner who might happen to catch ten seconds of it on his way home from church.. Each of the nine hundred "ass"-es in the song was scrambled (he offers to kick a lot of asses), as well as a "bastard" or two, and I think there's a "fuck" in there somewhere. They also bleepd out "rag" from the phrase "I'm back, on the rag, and ovulating" (or something like that), which is sort of silly, but whatever.

The absolute low point, though, was the verse where he offers to "go tit for tat with" somebody or another. Yep, they bleeped out "tit."

Censorship courtesy of Beavis and Butt-head, I guess. "Heh-heh, heh-heh, heh-heh-- he said 'tit'..."

Posted at 1:03 PM | link | no comments

Great Moments in Opinion Polling

Headline on the front page of the print edition of the New York Times sports section today (in Albany, anyway):

Shea Fans Don't Want Players to Strike

Yes, that's right, people at a baseball game don't want to see a baseball strike. Only in the New York Times do you get this kind of penetrating analysis and investigative reporting.

In future issues, I expect the Paper of Record to reveal that patrons of Tipsy McStagger's (no points for the reference) are opposed to a return of Prohibition, and fans interviewed at a Black Crowes concert were sorta, y'know, like, in favor of legalizing pot, man. Or something. What was the question again?

(To be fair, the column is about a more general (unscientific) survey of fans at Shea Stadium, and can be found online with a more sensible headline (registration may be required), so it's really more of a Great Moment in Stupid Headline Writing. But he did ask the strike question, and did get the "well, duh" response indicated...)

Posted at 9:38 AM | link | no comments

Move Along, Nothing to See Here

Well, I dropped off the "Blogs of Note" list. On the bright side, this probably means we won't completely shatter the bandwidth limits on

Anyway, I'm no longer noteworthy, so you probably shouldn't be reading this. If you'd like to go somewhere else, may I recommend The Library of Babel, where you can find a new entry on Greg Bear's Vitals?

Posted at 9:26 AM | link | 1 comment

Saturday, July 27, 2002

Trivial Solutions Don't Help

Another point of disagreement in the great voucher debate concerns what, exactly, counts as parental involvement. Eve Tushnet writes:

What vouchers do offer is the ability (and therefore the responsibility) to make a choice. Parents who are content with the public schools can choose to keep sending their kids there; many will. But the fact that they can choose to a) use their voucher money to attend a cheap private school for free, or b) use the voucher money, plus savings of their own, to attend a less cheap private school they couldn't afford before, means that parents will be able to be more involved in directing their children's education, not less.

The key point of confusion here is that, while choosing a school and writing the checks are important, they're not the sort of parental involvement I was talking about in my earlier comments. I'm talking about a daily involvement-- making sure that the kids do their homework, encouraging them to read books rather than watching tv and playing video games, taking an interest in their school activities, and supporting any academic goals they may have. Education is about more than just getting into a good private school-- there are no end of chuckleheads with Andover diplomas. Education, real education, requires an active interest in learning on the part of the student, the sort of interest that can easily be crushed by parental disinterest.

Private school doesn't necessarily provide that sort of parental support. Sure, having to shell out for the tuition provides some incentive for parents to take a more active interest in their children's education. But then, shelling out for a gym membership theoretically provides the same sort of incentive to actually exercise, and there are plenty of fat slugs out there having their credit cards dinged monthly by Gold's Gym. (I speak from experience, here...)

Private school without the sort of parental support I'm talking about is probably better than public school without parental support. But public school with active parental support is probably better than private school without.

Again, I'm just arrogant enough to think of myself as anecdotal evidence in favor of that claim-- I went to public school in the back end of nowhere, but thanks in large part to the efforts my parents made to encourage and support me, I was able to go to one of the very best colleges in the nation, side by side with kids from the very best private schools in the country, and I never felt intellectually or educationally inferior to them. In fact, the few people there who did strike me as much better prepared than I was were all public school products, while the biggest clowns I knew had diplomas from prestigious private schools.

Having to choose where to send the kids to school may be a net increase in the involvement of many parents, but it's not a particularly useful increase. And to the degree that it is an increase in parental involvement, it's also a tragedy.

Posted at 11:55 PM | link | 3 comments

You Want Fries With That?

So, I stepped into the "school voucher" quagmire last weekend, and seem to be stuck once again. Eve Tushnet responded to my most recent post, and a couple of people in the comments take issue with my post, in particular my characterization of vouchers as a "cop-out."

Before I get into the reasons for my statements, I'll repeat the full disclosure statement from an even earlier post: my father just retired from public school teaching after thirty-two years, and for many of those years he was an active member of the teacher's union. Accordingly, I have a great deal of sympathy for the teacher's side of these arguments, and none whatsoever for people who blame unions for everything (people who blame administrators for everything come closer to the mark...).

So, why do I say that vouchers are a cop-out? I say that because, from what I can tell, the real goal of most voucher proposals is to avoid having to actually think about the problems involved. Voucher advocates say we'll privatize everything, and then "competition and free-market principles" will take care of everything. None of the people running the system need to make any actual decisions about policy, they just need to run the system through the Magic Black Box of the Free Market, and everything will be wonderful.

The problem is, I don't find this an especially convincing argument, because it subtly misses the real point of the free market. Market competition doesn't ensure that someone will find the absolute best way to run a school, it ensures that someone will find the absolute best way to make money from running a school. The two are not necessarily the same. In one of the posts linked above, Radley "The Agitator" Balko makes a strained analogy to McDonald's in arguing for vouchers. Amusingly, I would use a superficially similar analogy to argue in the opposite direction.

If you believe the claims many voucher advocates make regarding the creative powers of the Free Market, you might expect that market competition in the food-service area would inevitably lead to gleaming, efficient, friendly restaurants nationwide, providing a rich and varied menu, and filet mignon for $5 a plate. Instead, what has it brought us? McDonald's.

The problem here is that quality is not the sole criterion people use when choosing where to get food. Price enters in, and convenience as well-- it turns out that if you forgo the search for gourmet quality entirely, and concentrate on providing mass-produced food cheaply and conveniently, you can make money by the bucketload.

You need some minimal quality, to be sure, but it turns out to be easy to meet most people's minimum quality standard. Thus, we have McDonald's and Wendy's and Burger King, and a half-dozen other big chains, making money hand over fist for selling food that, taste and nutrition wise is no great shakes. And it turns out to be very difficult to even stay in business running a restaurant that tries to provide high quality food, let alone make a lot of money at it.

This is the flaw in the market zealot vision of vouchers. In an ideal world, populated with perfectly rational (and spherical, and frictionless) people, market competition should lead to a wonderful education system, as only the schools providing the highest quality education would be rewarded with funding. But it's not an ideal world, and people are prone to irrationality, or working from different priorities than those who design voucher schemes. The result might still be quality education for all, but it might turn out that, in education as in food, convenience trumps quality, and the result will be, well, educational McNuggets.

So what should we be doing? Well, for one thing, we should be trying to figure out what it is that makes the best schools (public and private) work the way they do. Is it parental involvement? Rigid discipline? Better teachers? Small class sizes? Some combination of these? And, more importantly, is there a way to put these factors to work in schools which are currently failing? Can we get more parents involved in a positive way? Is there a combination of reforms and bonuses that can be used to entice better teachers into failing districts?

Once we figure out what works, and what needs doing, we should implement it, even over the objections of whatever entrenched interests are involved. If doing the right thing means going against the wishes of teacher's unions, the screw the unions-- I'm not going to back stupidity. If that means pissing off educational bureaucrats, well, screw them, too. If it means running trouble-makers out of school, and pissing off their parents, well, they should teach their kids better manners. If it means spending money, well, let's spend the money. If it means setting up schools run under several different systems, and shuffling kids around to find the best fit, let's do that. And, hey, if it turns out that the answer is something that can only be implemented in a private school setting-- say, religious instruction is the key factor-- then, by all means, let's go to a voucher system

If all that sounds like hard work, it is. It'll require a lot of detailed policy work to figure out what to do, and implementing the plan will require expending a great deal of political capital-- toes will get stepped on, and there will be a price to pay for that. Whatever the actual solution is, it will almost certainly be unpopular with a great many people. But it's the right way to attack the problem. Throwing up our collective hands and saying "the market will fix it for us" is a cop-out.

Posted at 11:53 PM | link | no comments

Tractor Beams and Thermodynamics

So, I promised (or was it "threatened"?) to finish explaining the recent Australian work on the Second Law of Thermodynamics. I've put it off for a while, but I really ought to finish that before moving on to the eight or ten other ideas I have for ways to delay packing stuff for the upcoming move...

As I noted in my previous post on the subject, there's a theorem that tells you when and where to expect to see entropy decreasing in small systems. Everybody pretty much believed in this "fluctuation theorem," but there weren't any experimental tests until this recent paper, for the very good reason that nobody could really see how to do the experiments.

The key problem here is that entropy isn't something you can readily measure. We've got a good handle on how to measure temperature, but something as nebulous as the "disorder" of a system of many particles is a little hard to measure. There are ways to express the entropy mathematically, but measuring the entropy content of real objects is a tricky problem. As Doug Turnbull notes, for a long time it was held that entropy "does not correspond to any directly measurable physical property, but is merely a mathematical function." Entropy has a real physical meaning, though, and it is possible to measure it, albeit indirectly.

The experiment devised by the Australian group is exceptionally clever. They look at the motion of a small glass bead held in an optical trap, and calculate the entropy change in the system due to the motion. The way they move the bead, and measure the tiny foces they need to measure for the calculation, provides the vague connection to laser cooling that I also mentioned in the previous post.

An optical trap is often described in popular talks or news articles as the closest thing you'll ever see to the "tractor beam" used in Star Wars or Star Trek. It's a wonderfully simple idea: if you focus a laser beam, you can trap small particles in the focus, and move them about.

The most common targets for these "optical tweezers" are micron-sized glass spheres. Conveniently, they're also used in the clearest explanation of the process I've run across, which I'll try to reproduce here: Imagine a beam of light hitting a little glass sphere. The sphere will act like a lens, and cause rays of light to bend around, and come to a focus on the far side of the sphere from the light source. A ray on the left side of the sphere will be bent to the right, and a ray on the right side will be bent to the left.

As I said when I was explaining laser cooling, light carries momentum. So, when you change the direction of a beam of light, you've changed its momentum, in the same way that deflecting a stream of water from a tap changes the momentum of the water. In the same way that the deflected water exerts a force on your hand when you deflect it, the bent light exerts a force on the sphere. Each redirected photon requires a "force" to change its direction, and in keeping with Newton's Laws, that leads to an equal and opposite force on the sphere. So a photon over on the left side of the sphere, that gets bent rightward, leads to a leftward force on the sphere, and the photons on the right side which get steered leftward produce a rightward force on the sphere.

If the light is uniform in intensity, these forces add up to zero. For every photon bent right, there's a photon bent left, and the leftward force is balanced by the rightward force. If the light varies in intensity-- let's say it's brighter on the right side of the sphere than the left side-- you get a force pulling toward the brighter part of the light. There are more photons on the right being bent left than on the left being bent right, which means that the rightward force is larger than the leftward force, and the beam moves toward the brighter light. If you focus the beam down, you create a single point where the intensity is a maximum, and the sphere will be trapped there-- any attempt to move it out of the focus will create a force pulling it back.

These "optical tweezers" are used in all manner of experiments, mainly with biological systems. They're an excellent tool for determining the mechanical properties of small systems, and can be used to drag single cells around. I may talk about some of those experiments in a later post-- there's fascinating stuff being done with optical tweezers (In keeping with my general policy of hyping my friends whenever possible, however, I'll throw in a link to the NIST experiments on optical tweezers). With some minor refinements (which I won't explain), it turns out to be possible to measure the exact force being exerted on a particle held in the trap at any given instant. That's the feature which makes the Australian experiments possible.

What they do is extremely simple-- they catch a small glass bead suspended in water in one of these optical traps, and then drag it through the water (by moving the cell containing the water, and holding the trap fixed). While they do this, they monitor the force exerted by the trap in pulling the bead along through the water. This force varies over time-- it's easy to see why if you think about it in terms of water molecules colliding with the sphere: if a bunch of water molecules strike the sphere at the same time, you'll need a bigger force to keep it moving, while if only a few hit the sphere in a given instant, you'll need a much smaller force.

By keeping track of the variation of this force, they can calculate exactly how much of a change in entropy was caused by moving the sphere through the water for a given amount of time. They repeat this many times, and for many different durations of motion, and count up how many times, for a given duration, they get a positive change (increase in total entropy), and how many times they get a negative change (decrease in total entropy).

What they find agrees beautifully with the prediction of the fluctuation theorem. For short times (less than a second), they find a fair number of experiments in which they measure a decrease in the total entropy, while for longer times, they find that entropy almost always increases. If you look at the motion for only a short time, you've got a reasonable chance (almost fifty-fifty for the shortest times in their experiment) of catching one of the events which leads to a small decrease in the total entropy. If you look at the motion for a longer time, those small decreases are wiped out by much larger numbers of events which increase the total entropy. The longer you look, the more likely it is that entropy will increase.

The data look great-- the effect is much clearer than I would've expected for something so subtle. They've also got computer simulations of the effect which agree very nicely with their observations. It's a very convincing paper. If there's a flaw to be found, it probably lies in the fact that this is a very indirect measurement, requiring precise force calibration of their optical trap, and knowledge of the exact temperature of the water and the bead. This is a well-understood technology, though, and the data are really very good. And it's not like the result is a shocking violation of known physics-- I'd expect this one to hold up.

What does it mean for life as we know it? I'll split that off into a separate post.

Posted at 2:41 PM | link | no comments

Laws of Thermodynamics Violated, Arthur Anderson Sought for Questioning

So, what does this all mean? Will Glenn Reynolds get his MAxwell demon air conditioner? Well, no. As Bob Park over at What's New puts it, "The title: 'Experimental Demonstration of Violations of the Second Law of Thermodynamics in Small Systems and Short Timescales,' says it all. The authors discovered that when statistical laws are applied to systems that aren't statistically significant, they don't work." I'd be a little less snide, as I think this is significant work (also, I don't have tenure), but the basic point is sound-- the Second Law is "violated" only for small systems and short time scales. We won't be seeing perpetual motion machines popping up all over the place any time soon, though some charlatans are sure to seize on this experiment as justification for their quackery.

What about the claims of the authors that "The results imply that the fluctuation theorem has important ramifications for nanotechnology and indeed for how life itself functions," then? I suspect that the sentence is basically just the sort of boilerplate hype you're obliged to tack onto any research article-- people in atomic physics almost invariably work in a reference to either Bose-Einstein Condensation or quantum computing-- but it's not an outright lie. It'd be a great shock to everyone if nano-scale engines worked exactly the same way as macroscopic ones, and some of the issues involved in the fluctuation theorem are sure to be involved. It's also true that we don't have that great a handle on "how life itself functions" on the molecular level, so you might as well invoke the fluctuation theorem there, too (in my snarkier moments, I call this the "Penrose method").

On the other hand, one of the salient features of the functioning of life is that, well, it works on longer time scales than those studied in this experiment. And if anyone ever succeeds in making functional nanotechnology, that, too, will need to run on longer time scales in order to be useful. The fluctuation theorem may slow the rate of increase of entropy fr a nanomachine, but then the Second Law never said entropy increased quickly, just that in the long run, it always increases. Nothing in this experiment changes that.

The Australian experiment is a very nice piece of work, and helps fill in the gap between the microscopic world of reversible physical processes and the macroscopic world of statistical mechanics and the Second Law. It's a significant advance in the study of mesoscopic systems, and a very clever piece of work. The future technological implications are likely to be pretty minimal, though.

Posted at 2:40 PM | link | no comments

Friday, July 26, 2002

A Different Religious Argument

A quick-hit this morning, as I have stuff to do. More later, maybe.

Over on the Good Ship Clueless, Steven Den Beste is pounding on the Mac vs. PC issue again. He's been harping on this for weeks now-- between this, Glenn Reynolds's hammering on BlogSpot (and his eighty-seven lame "rhinoceros" jokes), and Andrew Sullivan's tedious attempts to pin everything bad on Clinton, the people I depend on for the morning jolt of righteous indignation that I need to get me through the day are letting me down.

While I know that the Mac/Windows debates have a religious fervor exceeded (among geeks) only by the Emacs/vi wars, I've mostly lost interest, because I long ago realized that the specific hardware and software doesn't matter as much as individual Computer Karma. DenBeste can't figure out why some people prefer Macs to PC's, and devotes pages of text to deriding the system as inferior to Wintel. Meanwhile, I sit here in my office with a Windows machine that:

Now, granted, some of these are very specific to this computer. My home computer (a 500 MHz Wintel machine with 128 MB of RAM) plays MP3's without trouble, even when I have five or six other programs running. It's got an entirely different set of charming little quirks, most notably a tendency to hang up after I tell it to shut down, and a conflict between the printer drivers and some of the scientific software I use at home. But all in all, I just have bad Computer Karma with Windows machines-- the desktop machine I had at Yale was comically awful.

On the other hand, I spent six years in grad school working in a Mac-based lab, and never had these kind of problems. They needed to be restarted once a day or so, but then so do the PC's I use now. When they were running, they ran without the constant hassles I get from Microsoft-- there weren't any pairs of programs that simply couldn't be run at the same time, there weren't any conflicts between hardware drivers and completely unrelated software packages, and the hardware add-ons never caused the whole system to melt down. But then there was a Unix-zealot post-doc in the group who had the ability to reduce the Mac OS to a smoking pile of rubble just by wiggling the mouse back and forth.

It's all personal karma. I suffer constant aggravation when dealing with Wintel machines, but do fine with Macs, while others have the reverse experience. I'm something like two-for-nine lifetime at getting freeware programs written by German Unix geeks to work, and I've basically given up on the concept, but Kate has no problems with them.

The whole computing experience is so wildly variable that I'm skeptical of any attempt to draw sweeping conclusions about the relative quality of a particular platform. I certainly can't see expending the effort some Mac and Windows people do in calling each other idiots. Especially when Unix is clearly superior to both...

Posted at 10:15 AM | link | 7 comments

Thursday, July 25, 2002

Tools of the Trade

The other point where I wanted to take disagree with NZ Bear was regarding the tools used to keep track of weblogs:

First, nobody blogs if they don't think anybody is reading them. (Or at least, nobody I know). And right now, the tools available to us as blog readers are skewed to favor blogs that are updated very frequently --- and readers who are monitoring blogs continuously.'s main list is the worst example. It's great if you're monitoring it every few hours and looking to see when Glenn updates. But if you check it once every two days (let's not even think about only once a week) and are looking for three blogs that update about once a week, then good luck. You'll never find them; the tool isn't geared to that kind of usage.

Some add-ons to Weblogs' main data stream help; BlogTracker lets you select your list of blogs and shows you when they were last updated, and can be used to track blogs over long periods of time. But we need more --- more tools, more features on those tools, more flexibility in how to use them, and more independent tools that don't rely on the Weblogs,com data stream (because after all, the fatal annoyance of is that it requires the blogger to ping them. We need active monitoring tools to handle sites run by people who've never heard of

I agree that more tools and some new tools would be useful-- some sort of subject-based indexing would be nice, and a way to search for weblog posts on a specific topic would be helpful (several times since I started this, I've wasted an hour looking for some post that would be the perfect link to include, if I could only remember where I saw the damn thing...). But I disagree strongly about the "fatal annoyance" of and blogtracker, particularly for the "once a week" blogs the Bear is recommending.

My book log is done by hand. I didn't feel like learning to use new software when I started it, and I don't update it often enough to really require the features that Blogger or Movable Type would offer. I could change over to use some blogging software, but for the limited number of updates I do, the current system works fine. So I edit the files by hand, FTP them up to the server, and then ping

Of those steps, the ping is by far the least annoying-- it literally takes about ten seconds. And it's more than worth the trouble-- when I started pinging, I saw a clear spike in the number of people reading the book log. Also, that ten-second ping is all you need to get yourself listed on Blogtracker, which allows people to keep track of when you update, even if it's only once a week.

Better yet, the "fatal annoyance" is a complete non-factor for people using most of the popular blog tools. Blogger Pro (which I use for this site) has a simple check-box to automatically ping Movable Type has this as an option as well, and I think (but can't say for sure) that Radio does as well. If you use one of these tools, there's no excuse for not pinging them, and the people involved in the exodus from BlogSpot really ought to take advantage of the service. And the people relentlessly flogging the Blogger/ BlogSpot problems should mention this feature as well.

There's nothing wrong with and Blogtracker that can't be fixed by people making the minimal effort to use the available tools. More tools would be nice, but the ones we've already got are perfectly functional.

Posted at 12:00 PM | link | no comments

Wanted: Fewer Pundit Blogs

There's been a fair bit said about Salon's new blog site. As I've spent an awful lot of time droning on about physics the past few days, and don't quite feel up to another school voucher post (I'll get to it, but probably not until the weekend), I'll make a few comments about this, and put off the second part of the Second Law business until tomorrow.

I share some of Ginger Stampley's puzzlement as to what, exactly, you get out of running your web log with Salon that you wouldn't get from setting it up on your own. I also generally agree with her opinion that this is probably a good thing (leaving aside the question of who will have the time to read all these new web logs... Other than Glenn Reynolds, that is...). Sturgeon's Law will still apply, but any increase in the total amount of stuff will inevitably lead to an increase in the amount of stuff that's not crap (yeah, I know he originally said "crud" not "crap," but "crap" sounds better, damnit...).

The comments I specifically wanted to reply to were over at The Truth Laid Bear, where the Salon announcement is deemed Good in reference to an older post, calling for "Soccer Mom" web logs. There are a number of points here I want to take issue with, starting with:

To keep to what I know best --- the political end of the blogosphere --- I know what Stephen and Glenn and Mickey and Andrew have to say about homeland security. What I want to know is what the legendary soccer moms have to say about it.

Ultimately, I think I'm really not all that interested in having a flood of new web logs wherein "Soccer Moms" hold forth about homeland security. They'll have a slightly different perspective, true, but you know what? We've already got a whole host of web logs devoted to half-assed pontificating about politics. I think that I'd actually be more interested in a well-written web log where a "Soccer Mom" held forth on, well, soccer and motherhood.

That's a large part of why, as someone I found in my referrer logs noted, I go "on and on and on and on and on" about science. It's interesting to me, I hope it's vaguely interesting to others, and it's something that you don't see a whole lot of in the blogging world. I can't resist the temptation to occasionally hold forth about politics, but impressed as I am with my own cleverness, I'm not sure I really believe my political posts are any more insightful than those of Jim Henley or Patrick Nielsen Hayden, let alone people who do this for a living. And I know I rarely put things as well as the pseudonymous Charles Dodgson, and wish I could match Teresa Nielsen Hayden's stinging indictment of American politics (or, for that matter, her cooking ability, or her very funny essay on her excommunication from the Mormon church, though I think I could live without the ability to find pictures of Jesus eating roast guinea pig... But now we're getting way off track...). The one thing I know for sure I can do that these other people can't is talk about what it's like to be a physicist, and try to give people some idea of how a scientist views the world-- in other words, I can talk about my job.

Some of the best web logs out there are the ones about what other people do for a living. I've mentioned Derek Lowe's Lagniappe several times, and his reflections on medical chemistry were one of the things that convinced me this would be a good idea. Sydney Smith's Medpundit is also excellent (and will be added to the links bar the next time I fiddle with the template) for informed commentary on medical issues. I don't have the highest opinion of economics in general, and don't always understand the details he posts, but Brad DeLong's site is another great one for finding out how people in a different business see the world (and I'm not just saying that because he said nice things about my web log...). While his political stuff tends to grate on me, Steven Den Beste does provide some interesting insights into how engineers see the world. And the True Porn Clerk Stories journal that's hit the weblogging world like some sort of virus is just terrific for this sort of thing, which is the reason why it's been linked so many times.

The "blogosphere" is overrun with journalists and pundits and wannabe journalists and wannabe pundits presenting their view of the world. We're swamped in political opinion pieces, most of which end up looking very similar, even when they come from different parts of the political spectrum. Salon's new program is bound to add more political web logs to the flood, and may even, as Ginger Stampley notes, produce the lefty Instapundit that Jim Henley's looking for.

But what I'd like to see is more occupational blogging. I'm getting tired or journalists and pundits, and people pretending to be journalists and pundits. Let's get some more people writing about what they do for a living in other areas-- teachers talking about education, editors talking about editing, caterers talking about catering, detective talking about detecting, garbagemen talking about trash collecting. 90% of such web logs will be crap, of course, but the 10% that are good will probably be fascinating in the same way that "True Porn Clerk Stories" is. And it's almost got to be more interesting than yet another round of "adjectivePundits" talking only about politics.

Posted at 11:28 AM | link | 11 comments

Any Time Is a Good Time for Self-Promotion

There's a new entry over on my book log, covering Will Ferguson's HappinessTM. Quick review: the book tries hard to be a Thank You for Smoking for the self-help industry, but doesn't quite manage it.

As an aside, for some reason, I have trouble keeping people named "Will" straight in my head. I didn't read this for a long time because I was subconsciously attributing it to Will Self instead of the Will Ferguson who wrote Hokkaido Highway Blues, which I liked very much. In a blogging context, I always confuse Will Warren and Will Wilkinson (which I ought to be able to remember, Wilkinson being a Terp, and having written a good account of the Final Four riots this past year. Fear the Turtle, and all that... At least I didn't confuse him with Will Gay, who's a Dukie...). I don't know why that is.

No, I don't really have much of a point with this.

Posted at 10:14 AM | link | 1 comment

Wednesday, July 24, 2002

Entropy Always Increases, Especially in My Office

I'm going to have to start calling this weblog "Australia National University Science Watch," because they're back. (A good month for Aussie science...) I talked a week or two ago about "quantum teleportation" experiments done by their quantum optics group, while this week it's a group at their Research School of Chemistry that's making news, having reported the observation of violations of the Second Law of Thermodynamics. While this probably counts as a devastating blow to the arguments of creationist wing nuts everywhere, it's not quite the earth-shattering development that some of the press coverage might suggest.

Thermodynamics and Statistical Mechanics (the two are closely linked) are two of the most overlooked great achievements in physics. They involve the study of huge agglomerations of atoms-- macroscopic samples of gases, liquids, and solids-- and the bulk properties of those objects, as well as transitions between phases, and the behavior of engines. It's an extraordinarily difficult regime to work in-- the particles are far too numerous to keep track of the individual properties of each atom or molecule (though there are people who work on computer simulations involving huge arrays of particles), and yet through statistical methods and mathematical sleight of hand, the fields have managed to evolve a grand edifice of theory that is remarkably successful at connecting the microscopic behavior of atoms and molecules with the macroscopic properties of everyday solids, liquids, and gases. It's pretty amazing when you stop to think about it.

(Of course, there's a reason they're overlooked-- thermodynamics is very abstract and phenomenological, while statistical mechanics is very abstract and highly mathematical, and they're both about as exciting as public access cable broadcasts of village board meetings. Also, there's some sort of conspiracy in academia which ensures that StatMech classes never meet later than nine o'clock in the morning...)

The best-known achievements of the field are the so-called Laws of Thermodynamics, glibly paraphrased as 1) You Can't Win, 2) You Can't Break Even, and 3) You Can't Quit the Game. Somewhat more formally, the First Law of Thermodynamics is basically a re-statement of the Law of Conservation of Energy-- Energy can neither be created nor destroyed, but only changed from one form to another. The Second Law is generally stated as "Entropy always increases," the point being that in any real process, some energy is changed into a form that's not recoverable. The Second Law is the one that puts limits on the efficiency of engines, and rules out perpetual motion machines. The Third Law is most concisely presented as a statement that it's impossible to reach a temperature of absolute zero in a finite time. The Third Law really doesn't come up much, and some textbooks more or less skip it. Like I'm going to do here.

Another statement of the Second Law is that disorder always increases-- entropy, roughly speaking, is a measure of the "disorder" of a system. For macroscopic objects, and on long time scales, closed physical systems always move from a more ordered state to a less ordered state. You can see this by considering a glass of ice water as a closed system. Left alone for enough time, the ice will always melt-- the ice, with water molecules locked into a solid matrix, is inherently more ordered than the liquid state, where molecules are free to move about randomly in the fluid. You can re-freeze the water, but only by reaching in from outside the system and doing some work on it (and in that case, the entropy of the larger system (consisting of the water, you, and your freezer) will increase). Absent any outside intervention, the molecules in the water will never spontaneously re-form into an ice cube.

There's always been a bit of a problem with this, though, in that there are a lot of qualifications in that statement-- macroscopic objects, long time scales, closed systems (the last one, by the way, is the main one tripping up the creationist nut-jobs). Thermodynamics is very much a science of average properties-- it's very good at describing the big picture, but only at the cost of giving up the ability to look at the behavior of individual particles. And it's always been hard to reconcile the Second Law with microscopic physics.

You can sort of see the problem by considering an imaginary game of billiards. If you've got two pool balls sitting together at rest on the table, that's a fairly ordered state. According to the Second Law, then, when you hit those two with a third ball, and break them apart (into a disordered state, with higher entropy), it should be impossible to re-form the state with two stopped balls stuck together.

But for this three-particle system, it's conceivable that exactly that could happen. If you reversed the final velocities of the three balls, that's what should happen-- the three should collide, leaving the two colored balls sitting together and not moving, with the third ball traveling back from whence it came. Put another way, if somebody made a tape of the collision, and played it backwards, there's nothing in physics that would tell you that you were watching a tape run backwards-- you might be a little suspicious, but it's conceivable that this sort of collision of pool balls could happen. Given enough pool balls randomly bouncing around the table, it's bound to happen sooner or later, and anyone who's spent a fair bit of time playing pool (such as, for example, my sophomore year in college) has probably seen something like it. If you replace the pool balls with single atoms, this is a process that happens all the time-- it's called "three-body recombination," where three free atoms collide, leaving a diatomic molecule and one free atom, and people have made careers of studying it.

On the other hand, if you look at the case where a full rack of pool balls is broken by an incoming cue ball, you'd have to be a complete sap not to know if the tape were being played backwards. It's still physically possible to have fifteen colored balls and one cue ball come together and leave a nice, orderly rack with only the cue ball moving, but it's not the sort of thing you'd ever expect to see happen. With sixteen balls bouncing around the table more or less at random, there are an essentially infinite number of possible arrangements of velocities for all those balls, only one of which will end up re-creating the rack. It's not strictly impossible, but it's so wildly improbable that you'd never expect to see it. When you're not talking about pool balls, but about the billions and trillions of water molecules that would need to spontaneously re-arrange themselves to form an ice cube from a glass of cold water, it is impossible, at least as far as that word has any meaning in physics.

The point is that thermodynamics only really works on large scales, and in a statistical manner. On a large scale, there are an essentially infinite number of disordered states, but only a handful of ordered states, so the probability of randomly stumbling into one of the ordered states from a disordered one is essentially zero. Once you've moved to a state of higher entropy, once you've lost the initial order of the system, the ordering will never spontaneously re-form without help. So on a macroscopic scale, it's impossible for the entropy of a system to decrease without something from outside the system putting work in to make it decrease.

But when you start talking about very small systems-- a handful of particles, say-- there aren't so many more disordered states than ordered ones, and it's conceivable that a random arrangement of velocities could move you from a disordered system to an ordered one. It's not all that likely, but it's not so unlikely that it will never happen. So the Second Law doesn't really apply to small systems. You can extend the argument to show that it doesn't apply on short time scales, either-- processes involving smallish numbers of particles that reduce the total entropy by a small amount will happen all the time, and if you look for only a brief instant, and happen to catch one of those, you'll see a short-term entropy reduction. Over longer times, though, these few events will be completely swamped by a much larger number of processes that increase the total entropy.

The difficulty in making thermodynamics and microscopic physics play nice together is not a new problem-- the Australian paper that's caused such a stir this week cites an article from 1876 (not all that long after the invention of thermodynamics, really) that pointed this out. It's a problem that's been hard to quantify, though-- how small a system do you need to have before the Second Law seems to apply? For the billiard-table example above, the critical number is somewhere between three and sixteen, but it's hard to nail down quantitatively. It was finally quantified in 1993, when the same Australian group responsible for the current work came up with the "fluctuation theorem," a mathematical expression that tells you when you can expect to find violations of the Second Law, and how big those violations should be for a system of a given size, and for a given time scale.

The new experimental results are a confirmation of the fluctuation theorem for a system consisting of a small glass bead dragged through water. It's a very clever experiment, and the results look pretty convincing, but explaining the details (including a vague tie-in to laser cooling) will have to wait until tomorrow.

Posted at 9:33 AM | link | no comments

Tuesday, July 23, 2002


Having seen a huge spike in the number of hits over the past few days, and not wanting to overrun the bandwidth limits on, I've cut the main page down to displaying only four days' worth of posts. I have no idea how long the traffic level will stay this high (it appears to be due to Blogger deeming this a "Blog of Note." I'm flattered to be considered noteworthy...), but the front page was pushing 100 K as it was, which is a bit much on a dial-up connection. I also did some minor fiddling with the links over on the left.

The archive files will remain huge because, well, I'm lazy and don't feel like fixing them now.

Posted at 11:05 AM | link | 1 comment

More Moral Education

Eve Tushnet responds to my comments on vouchers. Since she doesn't have comments, and I'd like to respond before this gets too stale, I'll half-cheat and post two long things on a weekday (it's only half cheating because I wrote the laser cooling stuff last night, and posted it this morning...).

Eve read my post as arguing for a "strict separation of school and ethics," saying in part:

But also, I'm just not sure how UP would work this separation of "values" and schooling, for a number of reasons. One is the basic practical reason that you've gotta corral the kids somehow; you've gotta keep them from biting one another, lying, carping, etc. In order to teach math, you've got to start by building a rough-and-ready, low-level ethical platform, just so they'll listen to the math stuff. This is similar to Alasdair MacIntyre's point about the virtues required by certain practices- -chess requires virtues like honesty, for example (you can cheat at chess, but that ignores the point of playing the game).

("UP" is me-- I sound much perkier as an abbreviation...)

That's not really what I was after. I wasn't attempting to claim that there's absolutely no role for ethics in school, or that we should strive to make education utterly amoral (though some of the disciplinary policies instituted in public schools seem to be aimed that way...). Eve's correct in saying that some minimum standard of discipline is required to succeed in educational purposes, and some ethical content is inescapable, and there's nothing wrong with that.

But really, while there's some overlap between discipline and ethics, they're not the same thing. "Keep quiet during class because it's rude to talk while others are speaking" is a fine principle, and a good lesson for children to learn. For educational purposes, though, "Keep quiet during class because if you don't, you'll be sent to the office" is sufficient, but it counts as an ethical precept only in a very Old Testament fire-and-brimstone sort of way. Making sure that the students take the former lesson rather than the latter is properly the job of the parents, not the school system-- if you leave ethical instruction to the schools, you're more likely to get the latter than the former.

My real point was that imparting ethics is, at best, a secondary purpose of public education, and that the failure of public schools to provide a religious grounding in morality is not, to my mind, a strong argument in favor of vouchers. But there are a few different arguments tangled up here, so I'll try to disentangle them, and make my position a little clearer.

There are really two central questions: 1) Should we regard ethical instruction as a primary goal of education? and 2) Is a failure of the public schools to teach ethics a pressing enough problem to divert public resources to solve it? I read Eve's original post, in part, as answering "yes" to both, but especially the latter question-- that because "Public schools, a.k.a. government schools, can't teach the religious beliefs that many Americans consider to be the bedrock of all other values," we should provide vouchers to allow parents to send their children to religious schools, where they can receive proper moral instruction.

I would answer "no" to both questions, and especially the latter. The failure to provide an explicitly religious grounding in morality (or any grounding beyond "Obey the rules or be punished") is not a pressing enough problem that it needs fixing with tax dollars-- it's not on the level of trying and failing to teach basic literacy, which is a big enough problem to require repairs. If you want your children to learn the religious basis of moral principles, teach them yourself, send them to Sunday School, or pay for religious school on your own. Moral instruction is not a primary goal of the public education system, and religious instruction is most definitely no business of the state's.

Another point was really a matter of missing context. Eve writes:

A couple quick final points: UP writes, "Now we want to pay to shuffle the kids off into religious schools, to free parents from the hassle of providing moral and religious instruction as well? Are parents not supposed to play any role beyond paying for clothes and video games?" Wait now hey now. How does this follow? If I send my children to a school that will reinforce the beliefs I'm trying to inculcate in and model to my children, why does that relegate me to a parental ATM?

I say that primarily because I tend to think of vouchers as a cop-out, an attempt to improve education without requiring parents or legislators to take an active and continuing interest in the process. The lament about the lack of moral guidance provided in public schools struck me as piling on yet one more abrogation of parental responsibilities. It's not an absolute and inescapable result, but it was my immediate and cynical impression.

As to the larger questions of the purposes of public education, the reasons for choosing religious education (including some very good points about complicated traditions), and so on, well, I do have a day job, which I really need to get to. Comments on those issues will have to wait a while.

Posted at 10:48 AM | link | 2 comments

Clever Tricks and Cooling

So, at the end of yesterday's post, I had talked about how to use light to exert forces on atoms, and change their velocity. This is the basic tool used to do laser cooling, but it doesn't get you all the way there.

The problem is that, in the simple approximation we've been using thus far, the scattering force is as likely to cause an atom to speed up as to slow down. If you know what direction an atom is moving, you can aim the laser in the opposite direction, and use the force to slow them down (this is often compared to hitting a rolling bowling ball with a steady stream of ping-pong balls-- any one ping-pong ball doesn't make much of a difference, but enough of them striking the bowling ball in succession will bring it to a stop). You can even use this method to slow down a beam of atoms, but eventually they'll stop, turn around, and accelerate back the other way. And, anyway, we'd like to cool a gas of atoms, where the velocities are randomly directed.

To do real cooling with lasers, you need some sort of clever trick to arrange for the atoms to only absorb photons when absorbing photons will make them slow down. That is, they should only absorb when they're headed toward the laser. The quirk of physics which makes this possible is the Doppler Effect.

The Doppler effect is one of the great "you know this, but don't even realize it" effects in physics. It says that the frequency of waves emitted from a moving source will be shifted, depending on the direction of motion. It's most commonly encountered with sound (Doppler demonstrated his effect by putting a brass band on a moving train, and having them play a constant note as the train went down the track)-- sounds emitted from an object moving toward have a higher pitch (higher frequency) than the same sounds emitted from a stationary source, and sounds emitted from an object moving away from you have a lower pitch (lower frequency). This accounts for the way that a police or fire engine siren seems to change pitch when it passes you, and for the characteristic two-tone engine noise of NASCAR telecasts (rendered imperfectly in text as a sort of "EEEEEEEEEEEooowwwwwwwww" thing) and little kids pretending their bikes are cars, and for the way an aggrieved younger sibling's cry of "MMMMOOOOooooommm!!!!" changes pitch as he runs off to tattle. Well, OK, maybe not the last one-- the shift also depends on the magnitude of the velocity, and few small children move fast enough to produce significant Doppler shifts.

The Doppler effect affects light waves as well (as noted previously, like all quantum objects, light insists on being both a particle and a wave, at the same time). Doppler shifts of light emitted by distant galaxies are the primary evidence of the expansion of the Universe, and even smaller Doppler shifts of the light emitted by single stars are used to detect the presence of extrasolar planets.

The Doppler shifts seen by moving atoms (the effect is the same if the source is stationary and the receiver is moving) are a tiny fraction of the frequency of light waves, but atoms are incredibly sensitive frequency detectors. Atoms will absorb and emit only very specific frequencies of light, and a tiny change in the frequency of the light is enough to prevent absorption. Or allow it.

The trick to laser cooling is to set your laser to a frequency slightly below the frequency required to make a transition between two states in the atom (this is referred to as "red detuning" since the frequency is tuned to something other than the atomic transition frequency, and since red light has the lowest frequency in the visible spectrum). In that case, an atom at rest will see light that's not the correct frequency to be absorbed, and ignore it. No photons will be absorbed, so the atom will feel no force. An atom moving away from the laser (in the same direction as the beam) will see the light shifted even further down in frequency, and again, will do nothing.

An atom moving toward the laser, though, will see the light shifted up in frequency, and will absorb photons. When it absorbs photons, it feels a force in the direction of the laser, a force which acts to slow it down. Using a red-detuned laser, then, we can generate exactly the force we want to do cooling-- atoms which move toward the laser will be slowed down, while atoms moving away from the laser or standing still won't be affected at all.

If you take a single red-detuned laser, and direct it opposite a beam of atoms, you can slow and stop the beam, without having to worry about turning the atoms around and accelerating them in the other direction. With two beams of light aimed in opposite directions, you can cool atoms in one dimension-- an atom moving to the right will see the left-bound laser shifted up in frequency, absorb photons, and feel a force slowing it down, while an atom moving to the left will absorb from the right-bound laser, and slow down. Three such pairs of beams will get you cooling in three dimensions. Atoms in such a laser field are in the same predicament as a person trapped in a vat of sticky fluid-- no matter what direction they try to move, they feel a force opposing their motion. In honor of this sort of viscous behavior, this arrangement of lasers acquired the name "optical molasses" (one of my predecessors on my undergrad thesis project lobbied hard for changing the name to "optical treacle," but to no avail. He was a weird dude...).

(There are still some technical details and additional complications before you can use this to do real cooling of real atoms-- the biggest issue being that as the atoms slow down, the Doppler shift changes, and they stop absorbing photons. To slow or stop a beam of room-temperature atoms, you need to do something to compensate for the changing Doppler shift, either by changing the frequency of the laser ("chirping" the laser), or by changing the frequency the atoms want to absorb by applying magnetic fields to the atoms ("Zeeman slowing," after the Zeeman effect, which causes a shift of the energy levels for an atom in a magnetic field. Zeeman slowing is the idea that got Bill Phillips his share of the Nobel Prize for laser cooling.). Happily, the atomic transitions aren't infinitesimally narrow (a consequence of the uncertainty principle), rather there's some range of frequencies over which the atoms will absorb light, which means that you don't have to perfectly match the Doppler shift to get cooling. Once you've slowed a beam of atoms down from room temperature velocities, this allows you to cool atoms with a small range of velocities in optical molasses using a single laser frequency.)

Doppler cooling and optical molasses are the basis for all the success laser cooling has enjoyed. Further refinements of the basic scheme allow you to trap atoms (that is, confine them to a small region of space-- optical molasses is "sticky," but atoms can still wander out of the molasses region) as well as cool them to temperatures well below the limits suggested by the simple theory (For those keeping score at home, trapping was Steve Chu's contribution, while Claude Cohen-Tannoudji explained and improved the sub-Doppler cooling mechanisms. A fairly readable summary of the field's history (it really only dates from 1975) is provided by the Nobel Foundation. I won't go into any detail about that stuff right now...).

The laser cooling mechanism is strongly dependent on the specific properties of the atoms you're trying to cool-- you need a different laser frequency for each type of atom you want to cool, and only certain kinds of atoms turn out to have properties suitable for laser cooling. We're nowhere close to being able to laser cool beer. To date, something under twenty different atomic species (of a hundred-odd known elements) have been laser cooled (a partial list: lithium, sodium, potassium, rubidium, cesium, francium, calcium, strontium, helium, neon, argon, krypton, xenon. A few other species have been laser cooled as ions, not neutral atoms, and I'm sure I'm forgetting some others).

Still, to say that laser cooling has revolutionized atomic physics would probably be an understatement. Whole classes of experiments have been opened up that were previously thought to be impossible (we ran across a paper from the early 80's once that proposed an experiment, but then pooh-poohed it as wildly unrealistic. We found the paper because we had done the experiment described, and were looking for something to help explain the results...): ultra-cold collisions, ultra-precise spectroscopy, ultra-cold plasmas, atom interferometry, quantum state engineering, Bose-Einstein Condensation, and more. There are also numerous technological applications-- already, the world's best sensors of acceleration, rotation, and gravity gradients are based on laser-cooled atoms, not to mention the very best atomic clocks in the world (at NIST in Boulder and LPTF in Paris). In the future, laser cooling techniques could potentially have a huge impact on everything from atom lithography to nanotechnology, to nuclear physics, to quantum computing.

And all of that comes from the appealingly simple and wonderfully counter-intuitive idea that you can shine a laser on something, and make it cold. Even now, more than ten years after I first heard the idea, I still think that's just the coolest thing ever. Bringing this full circle to the beginning of yesterday's post, that's what got me into grad school, and got me to where I am today. I'm not sure whether that's an inspirational tale, or a cautionary one, but there you go.

Posted at 7:15 AM | link | 1 comment

Monday, July 22, 2002

Not Just Air Conditioning the Laser Lab

Last week, when talking about how to do a public lecture, I wrote that:

To get the basic message across, you really need to recall what it was about the field you're in or the problem you're working on that drew you in in the first place-- you just don't get to the Ph.D. level in a science without thinking, on some level, that the field you're in is just the absolute coolest endeavor ever conceived since our many-times-great-grandparents first rubbed two sticks together and set fire to the savannah.

For me, the thing that really drew me into atomic physics was the idea of laser cooling. It's a wonderful mix of simple and complex-- the basic idea behind it all is one of those forehead-slapping "Of course! Why didn't we think of that sooner?" sort of ideas (for a physicist, anyway), but when you sit down and go through it all in detail, it actually involves quite a bit of sophisticated atomic physics. To my mind, at least, it brings together all of the best things that physics has to offer: it's conceptually simple, but applying the concepts involves quite a bit of ingenuity; it makes manifest some of the weirdest behaviors in physics, but ends up having fairly concrete technological applications.

(It didn't hurt that one of the first times I heard about the field was as an undergrad physics major, when Claude Cohen-Tannoudji came to give a talk on campus. He's a wonderfully clear speaker, and does a marvellous job conveying the cool concepts without sacrificing theoretical rigor. His books tend to be exceedingly dry and formal, but he gives great talks...)

The essence of laser cooling is this: You take a sample of atoms, hit them with a laser, and the atoms get cold. "Laser Cooling" is not, as some people seem to think, about keeping your laser from overheating, but about using lasers to make things cold.

Right about there, I was hooked, just because it's such a wonderfully counter-intuitive idea. When you think about hitting something with a laser, you don't imagine that it'll get cold. You think of lasers cutting steel in industrial processes, or the Death Star blowing stuff up (real lasers don't merge like that, of course, but it sure does look cool...). So how do you use lasers to make things cold?

The first step in explaining this is to explain what, exactly, we mean by temperature-- before you can use lasers to make things cold, you need to know what it means to be cold. And the samples we deal with in laser cooling experiments are at least a million times less dense than air, so this isn't stuff you can just stick a thermometer into and read off a number. We need to look at what "temperature" means on a microscopic level.

Temperature is a measure of the average kinetic energy of a particle in the sample. A sample of gas is made up of millions of atoms zipping around with different velocities-- as a result, each of the atoms has some energy bound up in its motion. The average of this energy for all the atoms in the sample is what we call the temperature. In a "hot" sample, say a gas at room temperature, the atoms are moving at speeds comparable to the speed of sound. In a "cold" sample, they're moving much more slowly-- the molecules making up the liquid nitrogen I used for my demos on Saturday are moving at roughly half the speed of room-temperature nitrogen molecules. In a run-of-the-mill laser-cooled sample, the atoms are moving at something like 10 cm/s-- comparable to the speed of a running insect. Something that scuttles under the fridge when you turn on the light is moving about as fast as an atom in a laser-cooled sample.

So, the process of laser cooling involves using lasers to slow moving atoms down. That's a little more concrete, but not especially enlightening without two more key facts: First, that atoms have discrete energy states, and will only absorb or emit very specific colors of light; and second, that a beam of light can be thought of as made up of "photons," which behave like little particles.

The discrete nature of atomic states is the key to all of quantum mechanics. Indeed, it was the realization that atomic states have to be quantized that gives the theory its name. This is an idea that should be fairly familiar to anyone who's taken physics or chemistry in high school-- there are only certain very specific orbits which can be occupied by electrons in an atom, and each of those orbits has a very specific energy. Electrons can move between these states by absorbing energy from a beam of light, or by giving up some of their energy in the form of emitted light. The color of the light (or the frequency of the light wave) absorbed or emitted depends on the energy difference between states, so atoms will only absorb or emit light of very specific colors, determined by the limited number of transitions between allowed states. (There's a wonderfully cheesy applet demonstrating this at the Physics 2000 site.)

Physicists, fond as we are of abstracting away unimportant details ("Assume a spherical cow..."), prefer to talk about hypothetical atoms which only have two possible states, and thus only one transition between states. In reality, there are no two level atoms (and sodium is not one of them), and the multi-level nature of real atoms turns out to have significant consequences, but it's not a terrible approximation for a lot of systems, and it makes the explanation of basic laser cooling a lot simpler.

The light that's absorbed and emitted is also quantized, coming in discrete chunks called photons. Photons are generally described as "particles of light," and they carry the energy involved in the transition between states in the atom. As with everything else in the quantum world, they perversely insist on also having wave-like properties, so the energy carried by the photon is associated with a frequency, or the "color" of the light. If a photon of the appropriate energy comes along, it can be absorbed by the atom, which will use that energy to move to a higher ("excited") state. After some time in the higher energy state, the atom will spontaneously drop back down to the lower ("ground") state, emitting a photon with the same frequency as the one that was absorbed.

So far, so good (I hope...). The key to laser cooling is that, in addition to carrying energy, photons also carry momentum. In a very real sense, they behave like little particles-- when a photon strikes an atom and is absorbed, the momentum of the photon is transferred to the atom. A stationary atom hit by a photon will thus start moving, in the same way that a bullet fired into a block of wood will start the block moving.

The change in velocity isn't a big one-- a rubidium atom which absorbs a single photon changes its velocity by about half a cm/s, so it takes hundreds of thousands of photons to bring a room-temperature atom to a halt. But photons are cheap-- a fairly weak laser of the sort used as a pointer for a talk will deposit something like 10^15 photons on the screen in one second. That's a million billion photons per second, to wax Sagan-esque (well, OK, to really be Sagan-esque, I'd have to say "a miilllllion, biillllllion photons per second"). A hundred thousand photons is nothing.

So, light can be used to exert forces on objects. That's why it's so hard to get out of the house on a sunny Monday morning, right?-- you've got this constant hail of photons to fight your way through... OK, the force is actually pretty insignificant for a massive object, but for something sufficiently small, like a single atom, it can be substantial enough to make big changes in the motion.

(The other place this turns up is in the idea of a "light sail," common in science fiction. It's a different approach than laser cooling, but a similar idea-- rather than using smallish numbers of photons to produce big accelerations of small objects, you use astonishingly large numbers of photons to produce modest accelerations of big objects. If you could make a sufficiently large sail to catch the light of the Sun, you could actually generate a large enough force to move a space ship. You need a whole lot of photons, but again, photons are cheap, and for a big enough sail and a lightweight ship, you could theoretically move sizeable objects with the force of light...)

It's this light force that we use to cool atoms. Of course, they don't hand out Nobel Prizes for simple stuff, so there are a number of complications that have to be dealt with to get to cooling. Chief among them is the fact that the light force as described above is as likely to heat the sample as cool it-- you can use the light force to make fast atoms slow down, but you can also use it to make slow atoms speed up. To do cooling, you need to find a clever trick you can use to only exert forces that slow atoms down.

But this is running really long already, so that'll wait for another post...

Posted at 11:48 AM | link | 2 comments

Sunday, July 21, 2002

Sunday Schooling

Time for tiresome politicking. I just can't seem to get away from the school voucher arguments...

I ran across the following passage in a post by Eve Tushnet:

3) Public schools, a.k.a. government schools, can't teach the religious beliefs that many Americans consider to be the bedrock of all other values. In the absence of religious faith, public schools teach--at best!--a "civic religion" in which the claims of state and community trump the claims of God, since state and community are the only objects of loyalty that a public school can acknowledge. It is difficult to forge a civic order out of people who adhere to different faiths and believe that their God is more important than their country--on that point, the anti-voucher claim is correct. But this difficulty is intrinsic to a society that is a) mostly religious, b) diverse, and c) most importantly, free. You can't get around the difficulty by shunting poor kids into schools that extol loyalty to Caesar while being forbidden to mention loyalty to God. (As I said above, I don't think public schools actually do extol loyalty to Caesar all that often, but my point here is that civic loyalty is not the ultimate value, and I don't see why we should act as if it trumps religious loyalty or parents' responsibility to direct their children's moral education.)

While I'm not particularly religious myself (my family is Catholic, and I've been through most of the education and liminal rituals of the faith, so I have a respect for the tradition, but little deep religious feeling), I can sort of understand the feeling here. If something is that important to your life, you want to see your children brought up in the appropriate manner.

However (and there's always a "however"), I really don't see why this has anything whatsoever to do with the public schools. Faith and values are very personal things, and teaching them to children is properly the job of the parents, not the schools. The primary role of the school system is not to provide moral instruction, any more than it is to provide free day care. The primary role of the school system is to provide students with a basic grounding in the knowledge they will need to function as productive members of society. Civic values and free day care are secondary benefits, or ought to be.

If you want your children to have the proper values, it's your job as a parent to provide them-- indeed, the job is too important to be left to harried and overworked school teachers. Failure to mention loyalty to God is not a failure of the public school system-- extolling loyalty to God is simply outside their jurisdiction. Religious instruction is a matter for parents and clergy, not teachers.

Now, to be fair, the post quoted above is arguing against a claim that I find equally silly-- that public education is a unifying force that binds disparate groups into a unified citizenry. Again, to whatever limited degree that is true (anyone who speaks warmly of the unifying effects of public school doesn't remember junior high very clearly...), it's a secondary effect at best, and not the primary purpose of public education. If that is ever truly the main benefit we get out of public schooling, then it'll be past time to tear the whole system up and start over.

The quoted post is also primarily an argument in favor of vouchers for poor children to attend religious schools, not a plea to put God back in the public schools (at least, I hope it's not a plea for putting God back in public schools...). But even here, I'm not particularly happy about the implication-- this looks let yet another attempt to push parental responsibilities off onto others. Too many parents now expect the government schools to provide the sole educational force in their children's lives (resisting any suggestion that parents should encourage and supplement their children's education), and in many places, the schools have been forced to take up the additional burdens of teaching children the basics of health, and attempting to provide responsible education about sex and drugs, not to mention the day care aspects of the system. Now we want to pay to shuffle the kids off into religious schools, to free parents from the hassle of providing moral and religious instruction as well? Are parents not supposed to play any role beyond paying for clothes and video games?

But then, I've never entirely understood the motivation behind sending kids to religious schools in the first place, particularly when the goal seems to be the kind of moral indoctrination mentioned above. If you really and truly believe in the truth of your faith, and instruct your children in the faith, shouldn't that faith be strong enough to withstand contact with the real world? Indeed, doesn't it need to be strong enough to hold up against other faiths, other ideas, other cultures? You can't stand behind your children for their entire lives, ready to cover their ears and sing "La la la la la la!" whenever they encounter an idea that runs counter to your beliefs-- sooner or later, they need to stand on their own, and choose for themselves. Religious instruction that's never challenged is simply brainwashing.

The idea that the moral sense of children is so fragile that they'll simply fall to pieces if they're not constantly bombarded with religious values strikes me as close kin to the idiotic notion that the imagery of pop culture has the ability to mesmerize children and turn them into violent psychopaths. Kids are stronger and smarter than most adults give them credit for, and we do them a disservice by exaggerating their fragility.

In the end, this always reminds me of an old Dennis Miller bit, talking about one of the high-profile cases where parents sued a record company after a disturbed kid killed himself: "If your kid is going to be moved to suicide by anything Ozzy Osbourne has to say, you're not doing your job as a parent." Which is as good a summation as I can come up with right now, so I'll stop babbling.

Posted at 11:17 AM | link | 2 comments

A Great Morning for Vanity

OK, it's not like it's Page One of the New York Times, but yesterday's talk got written up in the Albany Times Union:

Smashing frozen flowers shows kids college is cool

As the class on laser cooling ended, the high school students crowded around the front of the Union College classroom, dipping flowers and balloons into liquid nitrogen, then smashing them to bits.

They had gasped in awe as Professor Chad Orzel poured some of the liquid nitrogen onto the table in front of him, causing the liquid to turn into steam the moment it hit the tabletop. When the discussion on the movement of atoms slowed, Orzel randomly tossed a racquetball at students to illustrate the random movements.

It was an attention-grabbing lesson, and that was the point. The 103 students -- mostly from minority families or the first person in their family to consider college -- are spending this weekend getting a chance to see what attending a university would be like.

(It's probably petty to want to correct the science errors in that...)

Now I have to go buy a paper... .

Posted at 9:25 AM | link | 3 comments

Saturday, July 20, 2002

Taken... Where?

One final liquid nitrogen note: In Googling for one of the links in the previous post, I ran across this wonder of pseudo-science, which contains the slightly alarming suggestion that:

Liquid Nitrogen taken several minutes after a workout and prior to sleep may potentiate maximum growth hormone output and increase nitrogen! Accretion of new muscle mass must involve an increase in protein syntesis released by nitrogenic compounds and further exacerbated by the influence of growth hormone.

Well. All right, then.

Posted at 10:00 PM | link | no comments

The More Demos, the Better

I did my Mr. Wizard act this morning for the high school kids I mentioned a few days ago. It's always good to do these things, or see them done, just as a way of calibrating how jaded scientists can become regarding some fairly amazing things.

My talk was about the basics of laser cooling (there's a nifty explanation at the Physics 2000 web site (it comes complete with video game applets that just have to be seen, and a cheesy question-and-answer format), if you're sick of waiting for me to do a plain-text version), and to provide a little context for what "cold" means in a laser cooling context, I broke out the liquid nitrogen (sorry about the hideous background on that page).

Nitrogen, as any geek can tell you, is a gas which makes up seventy-odd percent of air. If cooled to extremely low temperatures-- around 77 K (where one Kelvin is one degree Celsius above absolute zero-- 77 K is somewhere in the neighborhood of -320 Fahrenheit)-- it becomes a liquid which can be used for all sorts of things, from cooling experimental apparatus, to chilling ceramic superconductors, to freezing baseball legends. It's really common stuff in science circles, and while everybody in physics research has probably wasted at least one day playing with the stuff, it's easy to forget how neat the concept is if you haven't seen it before.

The classic liquid nitrogen demo is to dip flowers into the stuff, and chill them down. After a minute or so, you can tap the frozen flowers on the edge of a table, and they'll shatter like glass. It's a classic, but in some ways, it never gets old. The kids at today's talk loved that one, and several of them stuck around after I had finished to take turns freezing and then breaking things (the newspaper photographers who showed up (helping disadvantaged kids is good PR) loved that one-- they shot several rolls of film of kids breaking stuff. I'll have to check the papers tomorrow to see if that made it in). Another good variation on it is to take something elastic-- a racquetball, say-- and chill it in liquid nitrogen for a while. Where you previously had a nice, springy, bouncy ball, the frozen ball will shatter on a hard wooden floor. It makes a really loud cracking noise, and always gets a big reaction.

(Product Placement Moment: I bought four Penn racquetballs (warning: Flash) to use for this demo. The can advertises a two-for-one guarantee-- two balls to replace any one that breaks before the logo wears off. Prior to the talk, I jokingly suggested that I should send them the shattered fragments, and keep myself stocked up for the future... The first time through (I gave the same lecture twice, to two different bunches of kids-- it was surprisingly tiring...), the ball broke easily. The second time, the damn thing just wouldn't break-- I ended up having to fling it into the floor really hard to get it to crack. A third one was similarly resilient. Rather than sending in the pieces and asking for replacements, I'm tempted to send them a testimonial... "Even in the most extreme conditions, Penn racquetballs hold up!")

Even simpler demos are enough to really impress people who haven't seen the stuff before, though. As a simple demonstration of how cold the liquid is, I dumped probably three liters of the stuff out on a table, a little at a time, to show that it boils instantly on contact with the table. It makes an impressive cloud of vapor, and hisses and spatters all over the place (which makes it a good way of recapturing the attention of an audience that's started to drift...), but to anyone who works with the stuff on a regular basis, that's old hat-- when you fill a dewar with liquid nitrogen, it spatters all over as a matter of course. You learn to stop flinching at the idea of the drops hitting your skin-- they don't do any damage, due to the "Leidenfrost Effect." (This has led some wits in the science community to suggest that liquid nitrogen is best handled naked...) Still, this was impressive enough to some of the students that a couple of them asked me after the lecture if I'd just let them pour some of the nitrogen out on the floor...

The final demo I did is sort of an exercise in showmanship that I lifted from Bill Phillips when he used it for a public talk here. The key to it is that if you blow up a balloon and dunk it in liquid nitrogen, it shrinks dramatically as the gas inside cools, liquifies, or freezes. A balloon about six inches across (just under the width of the dewar) will collapse down to become a little pancake if you stuff it into the liquid. This means you can take a dozen or more balloons, each about six inches around, and stuff them into a dewar that's eighteen inches high. It works really well if you do them a couple at a time, saying "If you want to cool down a sample of gas, you'd think that putting it in liquid nitrogen would be a good way to do it," then cover the dewar, and go on with the lecture. The first two, the students didn't think much of it. The second two, a few of them started to notice that there was something weird going on. By the eight or ninth, I could hear them asking "How's he doing that?" The looks on their faces when I started throwing the pancaked balloons out into the crowd were worth the hassle of dragging the nitrogen tank over into the auditorium where I gave the talk...

(The point of the demo is to show that conventional methods of cooling don't work for getting most gases down to extremely low temperatures, as the gas will liquify, or even solidify. If you want to work at low temperature, and still have a vapor, you need to be clever about it, hence the need for laser cooling...)

The one drawback to doing these sorts of stunts is that the audience tends to remember the demos more than the science being discussed. This crew was no exception-- one pain-in-the-ass kid kept asking nitrogen related questions through the whole talk ("What would happen if you poured it out on your hand?" "It would sting. Please shut up.") Both groups wanted to know where to get liquid nitrogen ("I get it from a big tank in the next building. You can't get it, period. Unless you become a scientist."). Still, both groups had at least one student who asked good questions at the end, one of them a question of the "I was hoping you wouldn't notice that" variety, zeroing in on some stuff I'd swept under the rug. That alone was worth the sacrifice of a sunny Saturday morning.

Oh, and about the statement above that this was all in the interest of providing context for what "cold" means to a laser cooling person? The temperature of the liquid nitrogen Ted Williams is frozen in is roughly one million times higher than run-of-the-mill temperatures in laser cooling experiments-- we routinely deal with samples of atoms at a temperature of 100 micro-Kelvin, or a hundred one-millionths of a degree (Celsius) above absolute zero. With a bit of work, you can push that down by another three orders of magnitude, or more.

The details of how you get those temperatures will have to wait for another post.

Posted at 9:33 PM | link | 2 comments

Thursday, July 18, 2002

Everybody Walk the Dinosaur

I've been a little too busy to write up the promised remarks on laser cooling, but I did just update the book log, adding Michael Swanwick's Bones of the Earth. Capsule review: You've just got to like a book that contains the sentence: "Ponderously, the two triceratops began to mate."

Posted at 10:07 PM | link | 1 comment

Concrete Doesn't Grow

I tend to be skeptical of the frequent claims that we're running out of everything, and it's all America's fault. I'm not skeptical enough to accuse the people pushing these studies of being nothing but jealous Luddites-- I think they're reaching incorrect conclusions from good intentions-- but I really don't buy the idea that our wasteful lifestyle is depriving Bangladesh of critical resources. It's the "children are starving in Africa, so eat your peas" argument-- while it's wasteful to throw food away, eating it won't materially affect the lives of people in the Sudan. Likewise, the water that's stolen from the Colorado River won't magically appear in Ethiopia if only the people in Los Angeles stop showering.

Then again, there are days like today, when I had to step into the street five times on my walk to work, to avoid people's lawn sprinklers (a new record-- the average over the last few weeks has been more like two). Including the one rocket scientist who had placed the sprinkler squarely in the middle of the sidewalk. A couple of tips for my fine suburban friends:

Tip 1: If you raise the blade on your lawn mower to something more than half an inch above the dirt, the grass is much less likely to dry out and turn brown. It's a lawn, not the eighteenth green at Augusta National-- it's OK for the grass to be a little taller.

Tip 2: Having killed your lawn through irrationally exuberant grounds-keeping, you're not going to make it recover by watering the sidewalk. No amount of water poured on concrete will make it bloom, so your sprinkler system is doing about as much good as leaving the tap in your kitchen sink open all night.

A better use for the water in question doesn't immediately spring to mind (other than leaving it in the local rivers, for the next time I decide to go fishing), but anything would be better than this.

The grass is dead. Deal with it. And take the goddamn sprinkler off the sidewalk.

Posted at 11:44 AM | link | 4 comments

Wednesday, July 17, 2002

Washing the Car to Make It Rain

Dozens of people have observed that an announcement of light blogging to come tends to be followed closely by a caffeine- or boredom-fueled spurt of posting.

With that in mind, let me say that I expect to post several dozen things in the next few days, including a proof of the Riemann hypothesis.

In other news, I added a bunch of stuff to the links bar over on the left, and changed the link to point to Matthew Yglesias's new address.

Posted at 8:27 PM | link | no comments

Stopped Clocks and Blind Pigs

One of the latest mini-controversies to ravage the "blogosphere" is Brendan O'Neill's screed (astonishingly, the perma-link seems to work) about the quality of most weblog writing. Ginger Stampley calling him a "pompous little wanker" is one of the milder comments.

The hell of it is, he's sort of got a point. I don't want to diminish his pomposity and... wankitry? wankerdom? wankerhood?-- he is a pompous wanker, as his later rant about the superiority of British spelling makes perfectly clear. I'm not likely to ever win favor with him-- after all, I just posted 15 kB about public speaking-- but brushed clean of the spittle flecking his original post, some of his advice is halfway decent, particularly "Think before you blog" and "Be accurate."

You don't have to reject the whole blogging ethos or set yourself up as some sort of Credential Police to wish that people would take a little more care about what they post. I'd be embarrassed if I sent out email to friends containing some of the egregious spelling and grammar errors I've seen posted in the "blogosphere," let alone posting them for all the world to read, and I'm hardly the strictest grammarian you'll ever encounter (as anyone who's witness to my serial punctuation abuse can tell at a glance). As I tell my students when I talk about grading lab reports, there's no better way to convince a professor that you're an absolute moron than to turn in written work containing an obvious spelling error in the first sentence ("We preformed this experiment in order to..."). The same goes for weblog posts-- I tend to check after I update my book log, and look at weblogs with interesting titles, and there's nothing that makes me hit the "back" button faster than posts with bad spelling, cutesy IRC abbreviations, and no capital letters.

And would it kill people to check links before posting them? (This means you, Glenn Reynolds...) Everybody knows that Blogspot makes hash of archive links, and yet I see one post after another where the link 404's, or goes to a page that doesn't actually contain the post in question. It takes two minutes to run a post through a spell-check, and another two minutes to make sure that the links you include go where you want them to-- that's hardly a lot to ask. This stuff is being posted on the World Wide Web, for God's sake, to be read by hundreds or thousands of people-- it's in your own best interest to proofread your posts so you don't look like an idiot.

As for "think before you blog," I'm hardly speaking from the dizzying pinnacle of the Moral High Ground (again, 15 kB of rambling about public speaking...), but O'Neill's advice here is sound. Take a minute before you hit "publish," and re-read what you wrote. Then get a cup of coffee, check your email, and read it again to see if it still makes sense, or comes off as incoherent babbling. If it's babble, fix it or delete it. Yeah, fine, this will hold you to four hundred posts a day rather than eight, but the increase in quality should more than offset the decrease in quantity.

This is not a new argument to me-- I've spent a lot of time on Usenet, and this comes up again and again when some free spirit breezes in and can't be bothered with basic rules of English grammar and posting etiquette. And here as there, I just don't understand the motivation. You are what you post, in a very real sense, and I just can't see why you wouldn't take the minimal time required to make sure that your posts are coherent, easily readable, and as error-free as you can make them before you send them out before an audience of thousands, whose entire opinion of you will be based on what you write.

Sadly, these basic and sensible points, which the "blogosphere" would do well to heed, have been almost completely obscured by the more hysterical elements of O'Neill's rant.

(In accordance with the Iron Laws of the Internet, of course, this post will contain at least one error of the sort I'm complaining about...)

Posted at 11:03 AM | link | 6 comments

You Talkin' to Me?

Having been tiresomely political for the past few days, I feel like I ought to provide some actual physics content. Happily, I'm supposed to be giving a lecture to a bunch of high school kids on Saturday, as part of a program to encourage poor and minority students to attend college, so I can use this web log to help pull some of my scattered thoughts together into a moderately coherent public lecture. Of course, being an inveterate procrastinator, I'm first going to babble a bit about the different kinds of talks you get to give as a physicist.

One of the biggest misconceptions about science and engineering is that scientists and engineers don't need to be able to write well, or speak well. The popular image of a scientist is a sort of socially retarded obsessive, thoroughly enraptured by odd details of science, but shy and mumbling and inarticulate when talking to other people. There's a little bit of truth to this, mostly in the "obsessive" part, but the reality is that communication skills are at least as important in science as in other disciplines. You can have Nobel Prize-worthy data, but if you can't explain the results, in print and in person, well enough to convince other people of their worth, you'll never shake hands with the King of Sweden. There's a lot of writing involved in science, and a lot of public speaking, though not the same sort of public speaking done by people giving oral reports to their high-school English class.

First off, it's worth noting a cultural difference between disciplines. In the humanities, when somebody "presents a paper," that's exactly what they do. They write a paper on the topic of their research, and then stand up in front of an audience, and read the paper to them. Visual aids are rare, as far as I can tell, and while some people write and speak in a lively enough manner for this to be bearable, it seems generally to be about as awful as you'd expect from this description.

In the sciences, on the other hand, visual aids are mandatory-- if you're ever asked to give a presentation to scientists, show some pictures. The pictures needn't be all that relevant, but scientists are used to getting pictures to look at when we listen to a talk, and without some sort of visual element, we get cranky. It's also considered very bad form for a scientist to prepare detailed remarks in advance-- exceptions are made for people talking in a language that's not their best, but reading from index cards, or even sounding like you've memorized the text of the talk, will start dark muttering among a scientific audience. You're expected to be able to present a series of data slides, and talk about them in a more or less extemporaneous manner-- you can have bullet points or snatches of text on the slides as a reminder to yourself of what goes where, but on a sentence-by-sentence, word-by-word level, you're supposed to put it together as you go along. I've never heard an explicit statement of why that's the rule (you never do, with these "community standards" sorts of things), but I think the idea is that you ought to know your work well enough to be able to ad-lib a coherent explanation of it. Figuring out how to cope with these restrictions is something of an art, especially since they're so different from the standard public speaking tips and techniques you get in school, which are aimed at someone who's planning to give the Gettysburg Address, not a scientific presentation.

(Historically, there's also been a rather rigid division between scientific disciplines as to what visual medium they use. Doctors and biologists inevitably used slides, while physicists always used overhead projectors and transparencies (often hand-written). It used to be that you could walk into a room at a conference, and make a good guess at the background of the speaker based on how he was presenting his data. These days, though, more and more people are doing PowerPoint slide shows, in all disciplines.)

Within those constraints, there are three rough categories of talks a physicist can be asked to give: Research Talks, Classes, and Public Lectures. There's some overlap between categories (you can teach a class about your research, for example), and there are subdivisions within the categories, but those pretty much span the full range of possibilities, unless you include things like commencement addresses and admissions pep talks, which I'm not going to concern myself with, since I don't often get asked to do those.

Research Talks are talks given to other scientists, though not necessarily people in the same field. This category contains the two extremes of the difficulty scale, in terms of preparing a talk.

The easiest sort of talk to put together is, somewhat surprisingly, a long research seminar. These generally run something like forty-five minutes to an hour, and are given to an audience of other physicists in approximately the same sub-field you work in. These can be a gruelling experience to deliver, depending on how many questions are asked during the talk itself (I gave a talk to my old research group at NIST a couple of years ago, and brought slides for the thirty-minute version of my research talk (I knew the group well, you see...). An hour and twenty minutes in, we called a halt to let people go to lunch, and I skipped the last five slides in my stack. It wasn't hostile questioning-- on the contrary, that's one of the most enjoyable talks I've given-- but they weren't letting any details pass unquestioned). They're easy to prepare, though, because if you're any good at all, you know the research inside and out, backwards and forwards, upside down and sideways, and could talk about it for two hours standing on your head underwater. The biggest challenge here is realizing that the stuff you spend 95% of your time working on holds absolutely no interest for the audience-- nobody cares about debugging code or aligning optics, no matter how clever you were about doing those things. As long as you stick to the essential physics, though, these are easy to do, and the format is open enough to allow digressions and extensions if necessary.

The hardest sort of talk to prepare, also in the research category, is the contributed paper at a conference. Not coincidentally, these are also the hardest sort to listen to, as so many are done badly. Contributed talks are generally given a ten or twelve minute slot, with a couple of minutes at the end for questions. There can be almost a dozen of these in a session at a conference, so the time limits are fairly strictly enforced. These usually take at least three drafts before they're really presentable, and even the best of them are little more than a teaser for the real work, a plea for members of the audience to ask questions after the session is over, when they can be answered in detail.

The problem with contributed talks is that it's nearly impossible to condense actual new research down into ten minutes, and have the result be comprehensible even to other physicists. You need to ruthlessly trim out all sorts of material, provide just enough of a sketch of the background problem to put the work in context, and present a single new result in the most concise manner possible. This is exceptionally difficult to do-- worse yet, these talks mostly fall to grad students and junior postdocs, who often don't have much speaking experience, so the information transfer from listening to the average ten-minute talk is near zero. Unless the session is on work that's directly related to something I'm doing at the moment, or something I've done in the past, I tend to skip sessions consisting of contributed talks, and either seek out sessions with longer invited talks, or gossip in the hall with other people who are also bagging the contributed sessions.

Somewhere in between these extremes are the half-hour invited talk at a conference (generally given to senior post-docs or established researchers with important new results. I've been lucky enough to give a fair number of these, and they're nice-- not as easy to put together as a full seminar, but much more relaxed than a ten-minute talk), and the general colloquium (generally an hour-long talk, given to students and faculty in a variety of fields, which may not overlap your own. These take a bit more work, because you need to provide more context for people who don't know the details of the field; on the other hand, you're not likely to get asked really difficult questions in one of these, and it can be really rewarding if done well. I like to think I'm good at this sort of talk, and that's what got me my current job, but I could be kidding myself).

Classes are a different sort of thing altogether. When you're teaching a class, there's generally a very tightly prescribed amount of material you have to cover, and at the end of it, the students need to understand it well enough to answer questions about it later. That means there's no fudging on the math or glossing over the messy technical details (as there can be in a research talk, where the idea is to get the general impression of the key results across). On the bright side, though, it also means you're allowed to have notes-- indeed, it's a terrible idea to try to teach a class without notes. The three or four worst classes I've ever sat through, an the very worst class I've ever taught, were done without the benefit of lecture notes.

The requirement that students leave the class with some understanding of the material also means that for every new concept you introduce, you need to have three or four different explanations (there's always at least one student who doesn't get the first explanation, but will be enlightened by a different approach), preferably with concrete examples or at least analogies drawn from everyday life, to drive the point home. Demos are a good idea, too. Happily, physics is a field with lots of quality demos-- I can't begin to think how I would go about teaching a math class.

The biggest problem in prepping a class often turns out to be finding the enthusiasm for the material-- when you're talking about research, you're necessarily talking about something that you find interesting enough that you've chosen to dedicate at least part of your life to studying it in detail. I can babble for hours about my research, without getting tired of it. I can't work up the same enthusiasm for a lecture on, say, rotational kinematics or vector multiplication. But however dull you may find the material personally, you still need to find a way to put it across to the students well enough that you can use it as a jumping-off point for more interesting material later. Even if you're bored stupid by the whole concept of rotational kinematics, you need to pretend it's fascinating material in order to get students to remember it later. It's a challenge, and it doesn't always come off, but it's an interesting sort of problem, and fun when it works (sadly, it also tends to leave the students with the impression that you're absolutely the biggest dork ever to stalk the groves of academe, but there's little that can be done about that).

The last category is the Public Lecture, which is basically what I have to put together for Saturday. This is a talk about physics to an audience who knows nothing about the subject (or at least an audience who can't reliably be expected to know anything about the subject). These are also amazingly difficult-- probably just below the ten-minute talk, and just above the class lecture. (Happily, I've already got some slides for a freshman-level talk about laser cooling, and the sterling example of Bill Phillips's public talks to crib from guide me.) The challenge here is to distill the material down to the central, really cool essence, without sacrificing too much, and without actually lying to the audience. You're not trying to teach people the full details of what you do, but you're trying to get across the basic idea, and give some hint of the vast and exciting possibilities. Again, demos and real-life examples are a good idea, the more the better.

I haven't done a lot of these-- most of the public-type things I've done have been presented to people who already have a reasonable background in the sciences, which makes it easier. In a lot of ways, though, this is the most rewarding sort of talk to do. To get the basic message across, you really need to recall what it was about the field you're in or the problem you're working on that drew you in in the first place-- you just don't get to the Ph.D. level in a science without thinking, on some level, that the field you're in is just the absolute coolest endeavor ever conceived since our many-times-great-grandparents first rubbed two sticks together and set fire to the savannah. It's that excitement and enthusiasm that you need to convey, even in the smallest part, to accomplish your purpose.

Reminding yourself of that excitement is also a wonderfully re-energizing thing-- recapturing even a small part of whatever spark drove you into and through grad school is enough to wipe away a week's worth of aggravation from, say, tracking lost purchase orders and fixing stupid little parts. The gleam in the eye of someone who heard you talk and Got It is reward enough to wipe out the effects of years of toil and drudgery. That's why I volunteer to do talks like I'll give on Saturday, that's why I got a job teaching undergraduates, and it's a part of why I'm doing this weblog.

Wow. That ran a lot longer than I expected. Next time out, I'll talk about laser cooling. For now, I have talk notes to prepare.

Posted at 10:02 AM | link | 8 comments

Tuesday, July 16, 2002

When Is a Terrorist Not a Terrorist?

I've been discussing this a little over in Matthew Yglesias's comments section (Blogspot has made hash of his perma-links as usual-- it's the item that begins with a reference to this Matt Welch piece). The latest comment was starting to run a bit long, so I figured I should really swing it over here.

The issue at hand is the FBI's refusal to label the shootings at the El Al counter in Los Angeles International Airport as an act of terrorism. This has caused no end of consternation in the "blogosphere," with ringing denunciations of the cowardice of the FBI from all the usual quarters. I think this is a simple case of variant definitions, though, and I actually approve of the FBI's decision to back off calling it "terrorist."

I'm not going to pretend that the motivation of the LAX shooter wasn't essentially the same as that of Hamas or Al Qaeda. That would be ridiculous-- this was clearly a deranged act springing from the same source.

On the other hand, though, it's important to make the distinction between the deranged acts of lone maniacs who share a psychosis with Al Qaeda, and the acts of people taking their orders from Al Qaeda. This was, apparently, in the former category, rather than the latter, which is why the FBI is refusing to call it a "terrorist" act.

Yes, it's possible to maintain this distinction while calling the shooting what it was, an act of terrorism. I have no problem with that, Matthew has no problem with that, numerous other sensible commentators have no problem with that.

But it's a distinction easily blurred when the papers break out the 48-point type for "FBI Calls LAX Shooting Terrorist Act." We all know what would happen if the FBI had opted to call this terrorism from Day One-- the Washington Post and New York Times would have big headlines trumpeting the announcement, but also mentioning that he acted alone, the Washington Times and New York Post would scream "Terrorist Shoots Up LAX!", and bury the "acted alone" information on the bottom of page nine, and Fox News would openly call for bombing Baghdad in retribution. Within a few days, everyone would just assume that Hadayet took his orders directly from Osama Bin Laden. You can already see a bit of that in the scarier corners of the "blogosphere," though the FBI's actual announcements have served to focus the indignation on the FBI instead.

Losing the distinction between "act of terror by a lone individual working from the same hateful delusions as Al Qaeda" and "act of terror by someone working for Al Qaeda" is a step on the road to the Coulter/ Sullivan position that all Muslims are potential Al Qaeda fifth columnists, which is a step in a direction that I really don't want to see this country move. (Though the utterly loathsome new program mentioned by many yesterday seems to indicate that some of Our Intrepid Leaders are hell-bent on taking us down that road...)

One of the few bright spots in the immediate aftermath of 9/11 was the relative lack of anti-Muslim violence and hatred in this country. Yes, there were some incidents, but compare the handful of violent attacks here to the spate of anti-Semitic crimes in Europe. Indeed, there were enough positive incidents of people reaching out to Muslim neighbors and acquaintances to more or less offset the bad.That's something we can be proud of-- even in the darkest moments in recent memory, we were big enough, as a nation, to realize that there's a distinction between those abroad who hate us and would destroy us, and their co-religionists here, who don't, and wouldn't.

Since then, though, there's been a steady, poisonous drip of information and allegations seeking to undermine that. There are the continual "warnings" about possible Al Qaeda cells still active, possible future terrorist acts, and so on-- whether you think these are frantic ass-covering or cynical politicking (funny how the warnings seem to coincide with the release of new scandalous information), I think these have a corrosive effect. There are also things like this terrorist urban legend (via Little Green Footballs, where the comments section includes such charming sentiments as: "I should think any honest person who just happens to look Arab would be happy to be searched because it ensures his safety, too," apparently without irony), the aforementioned "TIPS" program, and the continued rantings of Anne Coulter and Andrew Sullivan, as they tip-toe their way along the line separating rational punditry from virulent bigotry.

I might be worried about nothing, here-- pulling a Kaus, as it were. But I'd rather not see any more fuel provided for those who like to insinuate that all Muslims are dangerous, and I think that's the intention behind the FBI's refusal to call Hadayet a terrorist. I'm not convinced they're really succeeding, but they're at least fumbling after the right idea, and I'm willing to give them credit for good intentions.

Posted at 11:24 AM | link | 3 comments

Monday, July 15, 2002

Department of Series Crossovers

Much-delayed posting tonight, because I wanted to put the new book log entry up first. Over the weekend, I picked up D. Graham Burnett's A Trial by Jury from the library, which I finished yesterday. This morning, Arts and Letters Daily provides a link to this article in The Atlantic about the problem of false convictions. It seems like an obvious sign that I really ought to talk about legal matters.

In some ways, the Atlantic article provides a bit of what I was hoping for in Burnett's book, but didn't get. The case Burnett drew for his jury service was a lurid one-- a stabbing in what may or may not have been a gay tryst gone awry. The defendant claims he was lured to the room under the impression that the victim was female, and the killing was in self-defense, to avoid being raped. The victim's somewhat campy friends claim that the defendant was, in fact, involved in a relationship with the deceased, and the killing was some sort of lovers' quarrel. Neither side seems particularly reliable-- the victim's friends didn't see the actual killing, and can't agree on many of the details of the case, while the defendant is almost certainly fudging some of the details of how he wound up in that apartment, possibly out of shame over occasional homosexual encounters (a possibility which resonates with some of Iain Jackson's recent comments). There's ample material here for exploring the murky workings of the justice system, and how consensus is reached in the jury room when presented with unreliable and conflicting testimony, but Burnett doesn't go far enough into that to satisfy me.

The Atlantic article covers some of the same ground, focussing on how it is that innocent people end up being convicted, and a couple of proposals to fix that problem, particularly in capital cases-- the article claims that something like 100 death row inmates have had their convictions overturned in the past three decades, a fairly appalling statistic (if accurate-- I'm too lazy to check it tonight). One of the problem areas mentioned-- witness identifications-- comes up in Burnett's book, but it quickly dismissed.

There's some fascinating material here, though it's not really treated in depth in either place. The problem of witness identifications alone is a good one, touching on all the classic problems of the fallibility of memory and so on (the tv show Homicide: Life on the Street did a good episode about this (a rare thing that late in the show's run), with multiple witnesses insisting they saw the crime, but unable to agree on any of the details; if you want something more highbrow, albeit not crime-related, see Copenhagen, or John M. Ford's "Erase/Record/Play"). Also dealt with in the Atlantic piece is the question of false confessions, which was the subject of a fascinating article in the Washington Post about post-Miranda interrogation techniques-- among other things, it asserted that the false confession rate now is approximately the same as it was back when cops were allowed to beat the hell out of suspects (alas, the article is long since vanished into their pay archives).

The most surprising thing is that, despite the simplicity of the fixes suggested (double-blind line-ups for witness identifications, and videotaping all interrogations), there's substantial resistance to implementing the changes. Which is surprising mostly because you would think that the police, too, would (or at least should) have an interest in seeing that innocent people are not convicted by mistake (though lawyers can quibble about the numerical aspects).

Then again, given travesties like this South Carolina case, maybe it shouldn't be so surprising.

Posted at 10:44 PM | link | 2 comments

Sunday, July 14, 2002

Split Screen Republicanism II: Electric Boogaloo

The term "split-screen Republicanism" is generally used to refer to Andrew Sullivan's assertion that "We do the national greatness stuff abroad and the leave us alone stuff at home." It occurred to me while reading recent news stories that another, no less fatuous split seems to be developing.

In foreign policy matters, it seems that George Bush is a master manipulator, managing to out-maneuver and out-wit all the leaders of Europe and the Middle East put together. It's all part of the grand scheme, what Charles Dodgson referred to as "an elaborate series of bluffs, feints, and jabs, a kind of diplomatic blindfold chess, at once treacherous and Machiavellian in its methods, and nobly Jeffersonian in its outlook and aspirations ."

Meanwhile, at home, he's a sort of, well, dim-witted rube, who can sit on the audit committee of a corporation that's engaging in dodgy accounting to cover its shaky financial situation, and get memos about the various problems, without managing to pick up any hint that it might possibly be a good idea to unload some stock before the excrement comes in contact with the ventilation system. He had absolutely no clue whatsoever, and just sold because he felt like it.

There's been a fair amount said touting Bush's extensive business experience as a job qualification. Now, even his own press people are making him out to be just another pointy-haired boss.

Posted at 4:46 PM | link | 1 comment

For Those Who Care...

Speaking of books, I just added a new book log post, on the first of Ellis Peters's Brother Cadfael books, A Morbid Taste For Bones.

Posted at 11:07 AM | link | no comments

My Theory's Better Than Your Theory

I don't really intend to have a regular Sunday item featuring the best book review quote of the week, but I'm doing it again.

I don't actually read a lot of pop-science books (a quick check of the book log turns up three in the last year: Nine Crazy Ideas in Science, The Odd Quantum and The Science of Discworld), a fact which occasionally surprises people who want to ask me about the latest Steven Hawking book. It's just a little too similar to work, so I prefer to unwind with, well, genre trash, mostly. I don't even read a whole lot of "hard" science fiction any more, for much the same reason that Kate, a proto-lawyer, can't watch "Law and Order" without yelling at the tv (she did an internship with the Manhattan DA, and reports a conspicuous lack of dark wood paneling in the real DA offices...).

That said, I do scan book review sections (including the reviews in Physics Today. Yes, I'm a geek...) for interesting possibilities. One such turned up in the New York Times today, where verteran pop-physics writer Lawrence Krauss reviews Hydrogen by John Rigden. The subject matter (at least as described in the review) makes for a fascinating story, and if nothing else, it produced a great swipe at string theorists:

Indeed, at a time when many books and news reports describe speculative theories that hope to probe deep cosmic mysteries but so far have failed to touch base with a single observation or experiment, it is a pleasant change to find a book on a humble topic that demonstrates the remarkable beauty and subtlety of nature, and of the experiments scientists have developed to explore it.

As a colleague of mine in physics puts it, the merger of quantum mechanics and special relativity that has allowed us to compare theory and observation at the level of better than a part in a billion -- the most successful confrontation between theory and experiment known in science -- may not be a theory of everything, but it is at least a theory of something.

It goes on the list of books I'll look for the next time I'm in Borders.

Posted at 10:28 AM | link | no comments

Saturday, July 13, 2002

Coming in 2012: Ken Lay International Airport

In this morning's Washington Post, we find this gem:

President Bush's top official on corporate crime and responsibility was a director of a credit card company that paid more than $400 million to settle allegations of consumer and securities fraud.

Larry D. Thompson, deputy attorney general and head of a new multi-agency corporate-crime task force, was a Providian Financial Corp. board member and chairman of its audit and compliance committee from June 1997 until his unanimous confirmation by the Senate on May 10, 2001.

His defense?

Thompson did not return calls for comment. "The deputy attorney general is proud of his service on the board of Providian. He only became aware of the [fraud] issues when regulators began to make inquiries," said his spokesman, Mark Corallo.

There's also this beauty of a sentence. Bet you can't guess what the reporter's thinking:

Thompson's service on the Providian board coincided with the time regulators said Providian engaged in fraudulent conduct. Providian settled all the complaints without admitting or denying wrongdoing.

I have two immediate reactions, one more mature than the other. The more mature of the two is: "Every time I think I couldn't possibly be more disgusted by the venal and incompetent clowns running the country right now, they take it to eleven..."

The other is: "See? Positively Reagan-esque. I told you so."

(I was going to bill this as part of my substitute Jim Henley act, but Unqualified Offerings has returned, so we'll just roll with the "shrine to the ego" aspect...)

Posted at 8:59 AM | link | no comments

Friday, July 12, 2002

Fighting Juvenalia with Juvenalia

There's been a bunch of noise recently about Mickey Kaus's bizarre claim that the often puerile Media Whores Online site is somehow likely to incite left-wing violence. This is easily the silliest thing I've ever seen from Kaus, even though I think his claims have been somewhat distorted by most of the people taking issue with them (MWO chief among them). Their antics are a far cry from, say, Gordon "Head Shots" Liddy, and it's hard to really make a credible claim that Liddy got anybody killed (as someone emailing Ted Barlow (whose permalinks are broken) points out, Clinton's attempt to link Timothy McVeigh to Limbaugh and his ilk was approximately as goofy as Kaus's statement, as is Eric Alterman's suggestion that Anne Coulter would be in jail if she were a liberal).

All in all, I'm fairly ambivalent about outfits like Media Whores Online and the relentlessly sophomoric Warblogger Watch ("The Corndog"? Stop. Please. You're killing me. No, seriously, stop.). They're shrill and often juvenile, but they're really not much worse than The Corner (where every third post has a smirky prep-schooler sort of tone, so the whole thing reminds me of a marginally more erudite Drones Club), or about three-quarters of the people Instapundit links to. And they are at least trying to perform a useful function-- I've said for years, half-seriously, that the Democrats need a Rush Limbaugh of their very own, and damn if MWO and their ilk aren't trying to fill the role. (The current leading contender, James Carville, is a little too vaguely reptilian to really be successful...) My personal inclination would be for more civil and rational discussion, but in a world where the virulently idiotic David Horowitz is often held up as some sort of deep thinker (yes, David, we should prosecute the New York Times for espionage-- just the other day, I was saying that what this country needs is more military junta tactics...), they're probably and regrettably necessary. They're not really good at it, but that's just because American liberals lack practice at this sort of thing.

(And as long as I've mentioned Horowitz, could somebody please restrain his hands, lest he sprain something patting himself on the back for putting a Pythonesque "Help, I'm being repressed!" scam over on a few college newspaper editors? I'd be more impressed if the Holocaust deniers hadn't beaten him to the idea (they were pulling the same shtick back when I was in college)... The only interesting element of the whole sordid affair was the tantrum he threw when the Daily Princetonian handled him exactly the right way. I bet that gets glossed over in his book...)

Posted at 12:58 PM | link | no comments

Thursday, July 11, 2002

The Transporters Aren't Working. Again.

So, having discussed how to do "quantum teleportation," how does this get us to "Beam me up, Scotty?" Well, that's the thing. It doesn't, not in any meaningful sense. What gets "teleported" is just the state of the initial quantum particle, not the particle itself. There's no reason why you couldn't do "teleportation" with atoms instead of photons (indeed, that's the next stated goal of the experimenters in the field), but again, all you're "teleporting" is the state of the atoms, not the atoms themselves. To "teleport" a person by this method, you'd need to already have a gigantic person-sized collection of the appropriate atoms at Bob's house, and copy the quantum state of the original patron of Alice's Restaurant onto those atoms.

It's also not true that "teleportation" inherently requires the destruction of the initial object, as is sometimes claimed. For photons, this happens to be true, as most photon measuring schemes involves the destruction of the photon, but the only thing that's necessarily destroyed is the quantum state of the original. If you were to do "teleportation" of an atom, the original atom would still be sitting in the lab at the end of the experiment, it'd just be in a different state than when you started.

This is why I put "teleport" in scare quotes throughout these articles. The process is almost completely unlike what we think of as teleportation: as most people picture it, teleportation involves atoms which start out at Point A disappear from there, and re-appear at Point B. All that really moves in this scheme is information about the quantum state, and it's not even clear that that matters, as noted by an IBM researcher. (You can imagine doing the experiment with a pair of atoms in the EPR state, rather than photons, which would give you a sort of trivial motion of atoms from one place to another. The more sensible way to "teleport" atoms, however, would be to use photon pairs, entangle them with the source atom, and transfer the atomic state to another atom.) It's not without technological possibilities-- this sort of thing could have implications in quantum computing, and possibly for what Jeff Kimble at Caltech likes to call the "quantum internet," a hypothetical future network of quantum computers-- but this isn't a clear route to sci-fi matter transmission.

This is another example of good work being over-sold. I'm not claiming that the research is uninteresting, or unimportant-- these experiments are really fascinating, and add to our understanding of the weirdness at the heart of reality-- just that the terminology creates an unrealistically inflated impression of the work. It's the scientific equivalent of political spin. Calling this "teleportation" is a wonderful way to get yourself in the New York Times and on the evening news, but the word carries a host of connotations that just don't fit with the actual experiment, and those connotations lead directly to endless Star Trek references, and things like the author of the original article speculating grandly that we'll be hopping between parallel universes any day now. That sort of boundless techno-optimism is vaguely charming, but it's misplaced, due to the unfortunate terminology. The work itself is impressive enough on its own; the Star Trek stuff is gilding a lily that, scientifically, doesn't need the help.

To their credit, most of the scientists involved try to distance themselves from such claims (some more emphatically than others, but they all at least hedge their bets). The problem is that the unfortunate name given to the process plants the idea in the minds of techno-enthusiasts and "futurists," and sticks the rest of us with dealing with the connotations and Star Trek questions.

(I should note that there are plenty of other problems with the Vegas article. The (sketchy) description of the process is slightly garbled in a manner that suggests the author is more a techno-enthusiast "nerd groupie" than an actual nerd. I don't want to give the impression that it's a good explanation of the issues involved-- most of the other links I've provided above and below do a better job. The Vegas City Life article happened to start me thinking about this stuff, leading to these posts, and that's all.)

Posted at 10:38 AM | link | 3 comments

Beam Me a Photon, Scotty

So, the last whopping huge physics post here covered the idea of quantum entanglement-- how do you get from entanglement to "quantum teleportation", which is what the article that kicked the whole thing off was about?

The first step here is to define what's meant by "teleportation" in this context. The idea here is that you've got one person, traditionally called "Alice" who has a quantum particle (we'll say it's a photon, to be concrete). She wants to get the photon to a second person, traditionally called "Bob," who needs it as part of a scheme for world domination, or something. It's critically important that Bob end up with a photon in exactly the same quantum state as the one Alice starts with, and for some reason that's never adequately explained, Alice can't just send him the actual photon she's got.

"Well, the answer is simple," you say, "she just measures the state, and sends Bob that information, and he can generate a photon on his end, and put it in the right state." Unfortunately, quantum mechanics doesn't work that way-- it's impossible to do a complete measurement of the quantum state of a single particle.

That's a little strange, right there, so I'll unpack it a little. To be concrete, we'll deal with horizontal and vertical polarization states again. If Alice's photon is exactly horizontally polarized, or exactly vertically polarized, there's no problem-- she can simply measure the polarization and report it to Bob. But Alice doesn't know what the state is-- it could be anything. Therefore, quantum mechanically speaking, it's some combination of horizontal and vertical polarizations. Again, in the interest of being as concrete as possible, let's say it's a 50:50 mix-- it's simultaneously both horizontally polarized and vertically polarized, and an equal mix of the two-- mathematically, we'd say the state is "H + V".

When Alice tries to measure the polarization state, she's essentially asking "Are you vertical?" of the photon. If the photon were exactly vertically polarized, the answer would always be "yes"; if the photon were exactly horizontally polarized, the answer would always be "no." For a photon in a superposition state, like the "H + V" photon mentioned above, the answer could be either. 50% of the time (completely randomly-- God, having grown tired of dice, flips a coin, and "heads" is "yes"), the answer will be "yes," and the other 50% of the time, the answer is "no." If you did the measurement on a hundred identical photons, you'd get (on average) fifty vertical and fifty horizontal photons; for any single photon, you'll randomly find one or the other.

Here's the tricky bit, though: after a measurement where the photon is found to be vertical, the photon will be vertically polarized, and only vertically polarized. If she tries to do a second measurement asking whether it's horizontal, the answer will always come back "no." Similarly, if her original inquiry about whether the photon is vertically polarized comes back "no," the photon is instantly and absolutely horizontally polarized, and a second measurement will always find it to be horizontal.You can't detect a photon state of "H + V" by first measuring "H" and then measuring "V"-- after the first measurement, the superposition state is destroyed, and the state is definitely and absolutely one or the other.

So, Alice sends a message to Bob saying "vertical", he sets his photon generator to "V", and he scheme for world domination fails, because he's failed to duplicate the original "H + V" state. The same thing happens if Alice detects a horizontal polarization-- after the measurement, her photon is in the "H" state, and Bob's out of luck, because he doesn't end up with "H + V." (It's not as obvious, but the same problem occurs if Alice tries to get clever and asks "Are you H + V?" of a pure vertical photon. Trust me.)

Essentially the situation is the same as with Schroedinger's hapless cat. Before the box is opened, the cat is both alive and dead at the same time, but once you open the box, it's either alive, or it's dead, and there's no going back to the original indeterminate state. What Bob wants is the indeterminate state-- he wants the cat to be both dead and alive when it gets to him-- so it's vitally important that Alice not "open the box" by measuring the photon state.

So how do you get around this problem? The answer is "quantum teleportation," the brainchild of a group of scientists working with Charles Bennett at IBM (Interesting side note: The guy in the middle of the back row in the group photo, Bill Wootters, taught my undergraduate Statistical Mechanics class). The key to the idea is to use the magic of quantum entanglement to transmit the state from Alice to Bob.

Alice, being a clever student of physics, gets herself a system that generates entangled two-photon states-- those "HV + VH" states I talked about last time, colloquially known as "EPR Pairs." She sends one of the two photons to Bob, and keeps the other one for herself. The state of the EPR photons is indeterminate, but she knows that whatever the polarization of her photon is, Bob's photon is the opposite. She's also got a photon of indeterminate polarization that she needs to send to Bob.

The clever trick is this: To "teleport" the unknown photon state to Bob, she makes a joint measurement on both of the two photons she has. She doesn't measure the individual states, but measures some relative property of the two. One way to do it would be to do a measurement to see if the two photons have the same polarization-- not what that polarization is, just whether they're the same or different. (The details of how to do this are a little tricky, but you can set up something that basically does the right thing) Doing this causes the state of the EPR pair to become entangled with the state of the photon she's trying to send to Bob-- if the two are the same, then Bob's photon is the opposite polarization of the one she's trying to send; if they're opposite, then Bob's photon is in exactly the state he's looking for. This happens instantaneously, via the "spooky interaction at a distance" that bothered Einstein so much. All she has to do now is send Bob the result of her measurement-- if the two photons were the same, then Bob rotates his photon's polarization by ninety degrees (changing horizontal to vertical); if they were different, then he does nothing. After that, nothing can stop Bob from taking over the world.

There are a few subtle quirky things about this that are worth mentioning: one is that the state moves from Alice to Bob without either of them ever having the slightest idea what it is. This is a very non-classical sort of operation. Another important quirk is that the process destroys the initial state-- it may not necessarily destroy the initial photon, but the state is necessarily changed in making the entangling measurement. Bob gets a perfect copy of the state that Alice started with, but Alice is left with (at best) a photon in a different state than she started with. "Quantum teleportation" is analogous to having Alice send Bob a fax, where she's not allowed to read what's on the paper, and the fax machine shreds it immediately after sending it. (As opposed to the usual state of affairs, where I write down an order, read it over, then fax it to an electronics vendor, where they shred it, leaving me with a perfectly readable copy, and them with no trace of the order...)

It's also important to note that no useful information is sent faster than light-- Bob's photon changes its state instantaneously, but until he gets the message from Alice telling him what she measured, he doesn't know whether he has the right state, or a state that's ninety degrees off. Alice's message has to go via classical channels, and can't travel any faster than the speed of light.

There have been a number of experiments done to verify that this scheme works. Single-photon states were "teleported" by a research group in Austria. With a little bit of work, you can extend the process to include states with large numbers of photons-- laser beams, for example-- and more information than just polarization states, but the basic idea is the same. The first experiment on laser teleportation was done in 1998 by a group at Caltech (with collaborators from all over the place). The Australian results mentioned in the article which kicked all this off (more comprehensibly explained in this New Scientist article-- they have a general teleportation article as well) are essentially a refinement of the Caltech experiment, using better lasers, and doing a slightly better job of conveying the state across the lab.

So what does this have to do with Star Trek? I'll talk about that in a separate post.

Posted at 9:40 AM | link | no comments

Wednesday, July 10, 2002

Department of Shameless Self-Promotion

As long as I'm posting a whole bunch of stuff, I'll note that there's a new post on my book log, reviewing Alex Irvine's A Scattering of Jades.

I'm done now. Really.

Posted at 10:24 AM | link | no comments

Spooky Interaction at a Distance

Yet again, SciTech Daily provides me with weblog material, this time in the form of an oddball article in the Las Vegas City Life archives (how do they find this stuff? It never would've occurred to me to look there...). The article is mostly about the perils of futurism, but the new development which sparks the article, and caught my eye, is a "quantum teleportation" experiment done at the Australia National University (Important Caveat: There's a tempting link in the upper left-hand corner of that page which promises a "Simple explanation of quantum teleportation." This leads to a 2.5 MB PDF file, which may or may not be simple, but definitely takes a long goddamn time to download. There's also a press release about the work, which is thoroughly uninformative, but does have a really cute chip-on-shoulder moment when it proclaims that the work "is ahead of similar efforts in Europe, Japan and the US; and demonstrates that truly world leading research is possible in Australia - if imagination, financial support and perseverance can be combined and nurtured.").

(Actually, what really caught my eye about the article from Vegas was the suggestion that one goal of the experiment was "getting every researcher involved in the project wildly fucked by nerd groupies." As one who has formally forsaken any involvement with nerd groupies (on advice of counsel, I should emphatically state that Kate is not a "nerd groupie"), I must say that I'm shocked-- shocked!-- at the idea that such work would be motivated by anything less than pure scientific curiosity. Well, mostly I'm shocked by the idea that they have nerd groupies in Australia (that's what I get for going to grad school in Maryland-- all they have in the D of C is political groupies), but I digress...).

The key idea in "quantum teleportation" is entanglement. I've mentioned this before, when talking about quantum computing, but it's worth going over again. As with the quantum computing posts, this will take enough set-up (I need to explain the "EPR Paradox" to explain how "teleportation" works) that the actual material about "teleportation" (and maybe a bit of ranting) will appear tomorrow.

Say you've got two quantum objects-- call them photons, to be concrete-- each of which has two possible states-- horizontally polarized or vertically polarized, for example. (Real photons can have polarizations at arbitrary angles, but you can thing of those as being a mixture of different amounts of horizontal and vertical polarization, so "H" and "V" are sufficient to describe the problem.) There are four possible states the two-photon system can be in: both horizontal (HH), both vertical (VV), or two possible states with one horizontal and one vertical (HV and VH). In general, until you make a measurement of the state, it's in a superposition of all four possible states at once: HH + VV + HV + VH. This is sort of a weird state of affairs, but once you get past the problem with the superposition of states (no small trick), it's a pretty mundane state. The states of the two photons are independent of one another-- If you measure one of them to be vertical, you're equally likely to find the other polarized vertically or horizontally. (You can think of it like a coin toss, if you like, with "H" being heads, and "V" being tails.)

However, imagine that you can do something to the system so that the states are no longer independent-- in laser experiments, this is generally accomplished by using special crystals that spit out two photons when struck by laser light, with a very specific relationship between the polarizations of the outgoing photons. The details don't really matter, what matters is that the end result is a state where the photon polarizations are correlated. If one is horizontal, the other is vertical, and vice versa. Until you make the measurement, the system is still in a superposition state, but now there are only two possible states in the superposition: HV + VH.

"Big deal," you say, casually. It doesn't sound that surprising, really, but it's an exceedingly troublesome idea: Imagine taking the two photons, and shooting them off into space in opposite directions. Let them travel for, say, a year before you measure the state of either. At this point, they're two light-years apart-- something like twelve trillion miles. Now, imagine that you have some space alien friends with really good clocks sitting out there waiting for the two photons. Alien A measures one of the two exactly one year after it was sent out, and Alien B measures the other exactly one year and one nanosecond after it was sent out. If they get together afterwards, and compare results, they'll find that their measurements are exactly and absolutely correlated-- if A finds horizontal polarization, B will find vertical, and if A finds vertical, B will find horizontal. You can repeat the experiment a million times, and every time the two will have opposite polarizations.

"Big deal," you say again. "That's the way we set it up-- when they left the crystal, one was vertical and the other was horizontal." But that's not how it works. According to quantum mechanics, the state is indeterminate until the measurement occurs. Until A measures the state of that first photon, the system is simultaneously in both HV and VH. The instant that A makes the measurement, though, the state of both photons is determined. Which means that, somehow, photon B has to know that photon A was just measured. But they're two light years apart, and B was measured a nanosecond after A-- a signal from A to B saying "I was measured! You're horizontal!" would need to travel at 18,840,000,000,000,000,000,000,000 times the speed of light, which is ridiculous.

This bothered Albert Einstein to no end-- after all, his claim to fame was proving that light speed was an absolute upper limit. The thought experiment described above (in slightly different form) was first posed as a paradox by Einstein, Boris Podolsky, and Nathan Rosen, as a counter-argument to disprove quantum mechanics. Einstein famously referred to the connection between the two particles as a "spooky interaction at a distance" (which is a great phrase, probably one honkin' big word in German, and really ought to be appropriated as a description of Usenet newsgroups or weblogs...). This gedankenexperiment (another great German word) is known as the "EPR Paradox" in honor of the three authors of the original paper.

(One of the great ironies of the history of quantum mechanics is that Einstein's work is one of the major pillars on which QM rests, and yet he himself found the theory philosophically distasteful, and spent his later years trying to find a replacement for it. He's famously quoted as saying saying "I cannot believe that God would choose to play dice with the universe." Only slightly less well known is this rebuttal from Pratchett and Gaiman's Good Omens: "God does not play dice with the universe; He plays an ineffable game of his own devising, which might be compared, from the perspective of the players (i.e., everybody), to being involved in an obscure and complex version of poker in a pitch-dark room, with blank cards, for infinite stakes, with a Dealer who won't tell you the rules, and who smiles all the time.")

In order to get out of the EPR paradox, you need to do one of two things-- either you need to sacrifice the indeterminacy of quantum mechanics, and develop a new theory in which the states of the individual particles are well defined through the whole experiment, even if they're not known to the experimenters (such theories are called "hidden variables" theories, and that's pretty much what Einstein was angling for); or, you have to sacrifice the whole idea of "locality," the idea that particles are in specific places, and their properties are determined in those places-- in essence, you have to say that the two photons are actually a single quantum system, even though they're twelve trillion miles apart. Throwing away locality requires you to accept (paraphrasing an old textbook of mine) that the result of a random process occurring in one place can affect the result of another random process occurring at the same time in another place. Neither of these choices is particularly appealing, and it's not immediately obvious how to distinguish between them.

In 1964, however, John Bell proposed an ingenious experiment which could distinguish between hidden-variables theories and non-local theories. In particular, he was able to show that the results of a certain set of measurements had to satisfy a certain inequality for any conceivable hidden-variable theory. If Bell's Inequality is satisfied (or violated, depending on how you look at it), then there is no possible way to explain the results with a hidden-variables theory, and locality goes out the window. The first experimental tests of Bell's Inequality were done by Alain Aspect and co-workers in 1982, and showed fairly conclusively that locality had to go. There are still people who argue that the experiments haven't completely ruled out all counter-arguments, but most physicists regard this as a settled issue. Einstein was wrong, quantum mechanics holds up, and we live in a non-local world. (Explaining the details of Bell's Inequality and the various debates about it is a topic for another post-- if you're interested, here's a concise formal summary from a few years back, or you can Google on "Bell's Inequality" and "EPR Paradox" for a wealth of other material).

This business of non-locality is another example of the deep and fundamental weirdness of quantum mechanics. It's yet another pillar of the classical philosophical picture of science that had to be cast down to deal with a quantum world, and it doesn't fall easily. We like the idea of locality-- it makes life much simpler.

Happily, as with most of the other weird features of QM, non-locality and EPR states also turn out to open the way for interesting technological applications, particularly in what's known as "quantum cryptography" (which I'll talk about another time). These are also what make "quantum teleportation" work, but I've nattered on for rather a long time already, so we'll save that for tomorrow, along with a bit of a rant about the over-selling of some experiments and the perils of science by press release.

Posted at 10:06 AM | link | 1 comment

Get Your Substitute Unqualified Offerings Here...

An unintentionally humorous Instapundit moment:

I MISSED THE WHOLE HARKEN FLAP last week, and I'm still not clear what it was about. But this post suggests why it's already died down.

The link 404's. Yeah, it's just the Blogspot Archive Bug (it's not hard to find the post he's trying to refer to, but hardly worth the bother), but I like the 404 as a sort of statement that the issue hasn't actually died down, but just can't penetrate the meter-thick baffles of willful ignorance protecting the Offical Blogosphere Echo Chamber...

(Yeah, fine, it's a cheap shot. It's also not especially Henley-esque. There's a big long post about quantum mechanics coming, let me have a little fun...)

Posted at 10:00 AM | link | no comments

Tuesday, July 09, 2002

Lies and Damned Lies

It's been a rough couple of months for the New York State Education Department. First they get slammed for their bowdlerized Regents Exam in English, and now they're taking heat for the "too-hard" physics exam (stories about the problem have appeared in the New York Times and New York Post). This one's particularly depressing, and not just because I can probably expect to have some of these students complaining about my grading next year...

As a discipline, physicists tend to pride ourselves on our grasp of statistics-- maybe not the high-level statistical arcana understood by mathematicians and people at the census bureau, but on a common-sense sort of level. Given that no experiment is ever perfect, and random errors are inescapable, the progress of science is necessarily a statistical process-- you can make statements about uncertainties, and confidence levels, and the statistical probability that your results are correct, but never attain absolute graven-in-stone TRVTH. Understanding and interpreting new results in physics requires a good grounding in statistical matters-- given some number of data points, how many do you expect to fall outside the error bars? how much confidence can you have in extrapolating from that sample to a general rule? what sort of deviation from a prediction do you need to have for that deviation to be significant?

This familiarity with error and uncertainty has allowed the field to produce some great debunkers of pseudo-science-- Bob Park of the University of Maryland and the American Physical Society is one of the best, and his What's New feature (linked over on the left) is a good source of material about foolishness and fraud in science and science policy. (Wandering even farther afield, I'll note that one of the most entertaining and informative conference sessions I attended at the APS's Centennial Meeting in Atlanta was the "kook session" in which Park and the great James Randi held forth on various flavors of pseudo-scientific idiocy, mostly in medicine, which is something of a target-rich environment for satire or moral outrage, whichever you prefer...). Robert Ehrlich's Nine Crazy Ideas in Science is also a worthy entry in the canon, doing a nice job pointing out statistical chicanery in a couple of high-profile cases. Physicists are also prize the ability to make back-of-the-envelope estimates, and do simple common-sense analyses and experiments on the fly-- the most famous example being Feynman's performance at the hearings about the Challenger disaster.

That's why it's especially depressing to see a physics teacher complaining to the New York Post that one of his students got a raw score of 68 (i.e. 68 percent of the questions were answered correctly) and had that scaled down to a grade of 65 (out of 100). Yes? And? 65 and 68 are not so different, and as I keep having to remind students, grading on a curve doesn't mean that everybody's grades will go up.

On the web site linked above, the state provides a very detailed explanation of the grading, and the changes in the test format (PDF file of the release). This all seems perfectly reasonable to me-- as they rightly note, some questions are easier than others, and it's not right for those to be given the same weight as more challenging questions.

The biggest change in the format is also a sensible one-- in previous years, students have been able to choose from a set of "blocks" of questions about various topics. Thus, it would be possible, in principle, for a student to score 100% without knowing a thing about Solid State Physics. While this format tends to be popular with students (I had several requests for it in classes this year), it's not really right-- if you're going to test knowledge of the material, you need to test on all the material. The optional blocks of multiple-choice questions were eliminated this year, in favor of more "extended answer" questions. In my opinion, this is a positive move-- multiple-choice questions are a reasonable way to test basic conceptual understanding, but you need to pose actual problems if you want to know whether someone really understands the material.

The fundamental problem here is that high scores have come to be viewed as an entitlement, not an achievement. Physics is a hard subject, and a fair test of the students' real understanding of the material isn't likely to find 33% of the students scoring between 85 and 100, as in past years. This year's figure of 16% sounds a whole lot more reasonable-- it might be on the short side, but not by a factor of two (I've had 11% of students score above 85% on the final exam over the past two terms of introductory college physics, though those were admittedly very tough exams). A 33% failure rate is high, but probably not a wildly inaccurate assessment of their actual knowledge.

Unfortunately, students and parents aren't after accuracy, they're after high grades and positive feelings. And all too many teachers go along with them.

Posted at 11:41 AM | link | no comments

Monday, July 08, 2002

Hey, Ref!

I've just been asked to referee a journal article, for the fourth time in the last seven months. Since "peer review" is often cited as the cornerstone of modern scientific research, and since most people probably don't have a clear idea of what's involved, and since blogging about it is a convenient way to procrastinate my way out of actually reading the paper in question, I'll talk about the peer review process a little bit.

The basic idea, found in any philosophy of science textbook, review of Stephen Wolfram's new book, or rant against "Intelligent Design" theory is that science advances toward the truth through a process of tests and verification. New results by a particular research group are submitted to the larger scientific community, described in enough detail for other researchers to be able to check the validity of the work and attempt to duplicate the results. If new experimental results are repeatable, or new theoretical predictions are confirmed by experiment, those results will gain acceptance, and form the basis for the next incremental step forward. Peer review, the initial vetting of submitted papers by qualified scientists which takes place before publication of a journal article, is one of the cornerstones of this process.

The reality of the process is, of course, a little messier. The way the process works in practice, from the author's point of view, is that you pour sweat and blood and tears into crafting a concise but complete description of your work, which you ship off to a journal, who sends it out to some anonymous reviewers (usually two of them), who spend the next six weeks ignoring the paper and the badgering notes sent to them by the journal editors, then callously rip your work to shreds and insist that you make major changes that push the paper over the journal's length limits, leading to a big fight with the editors.

From the referee's point of view, of course, this looks completely different. As a referee, the way the system works is that the journals wait until you're out of town for some rest and relaxation, then email you a note saying "We'd like you to review this paper. If you don't respond in the next fifteen minutes, we'll assume you agree, and send you the article." By the time you get back, you're implicitly committed to reading some inscrutable gibberish from a field you've never worked in, which was originally written in Chinese before being translated into Portugese, then Pashto, then Finnish, and finally into English via the Babel Fish. You're teaching four classes, writing a paper for another journal, and you've been called for jury duty on a capital murder case and sequestered, so you put off reading the paper for a little while, only to get a barrage of nasty letters asking when they can expect your report. Then, when you do submit a report ("Please, please, please, ask a native speaker of English to proofread this for you."), the authors have the temerity to take issue with your carefully constructed comments.

OK, so maybe that's slightly exaggerated.

The way it works is that a paper presenting new results is sent to a journal, where the editors check it quickly for general suitability (i.e, they make sure that it deals with physics rather than political sciecne), then send it out to two referees, chosen from a pool of people whose names, addresses, and areas of expertise are kept on file at the journal (these, in turn, are drawn from the people who've published papers in that journal in the past). The referees are asked to read the paper, and judge the quality of the science: is it original work, is it factually correct (or at least plausibly so), does it provide all the necessary details, does it generally increase the store of human knowledge? Referees also make recommendations based on the form of the paper-- is the writing clear and are the figures comprehensible?-- and depending on the journal may be asked to make judgements on more nebulous criteria like "importance in its field" or "general interest." Based on the comments of the referees (who remain anonymous to the authors), the paper can be accepted immediately, rejected outright, or sent back to the authors, with the comments attached, for whatever revisions are needed to make it acceptable.

As indicated by the exaggerated descriptions above, this is a gigantic hassle for everyone. Papers in the more important journals (Science, Nature and Physical Review Letters) are subject to very strict length limits, so it's not always easy for the authors to make the changes, and scientists are a prickly bunch when it comes to outsiders criticizing their work, so referee comments can lead to big fights. On the referee's side, reading a paper closely enough to make the necessary comments is incredibly time-consuming-- it's not quite as bad as the "source cite" process student law journals use (mostly due to the lack of free student labor to check the fiddly little details of the formatting), but getting enough of a picture of a slightly foreign field to be able to place the paper in context and jdge its importance takes a bit of work (though it often turns out to be rewarding). Additionally, the length constraints tend to force a terse and jargon-laden writing style that can be difficult to decipher (but easy to parody), even for a trained professional. In general, authors submitting papers tend to regard the process as one of those pain in the ass things that you just have to get through by whatever means necessary (sort of like meeting the seemingly arbitrary formatting requirements most journals set), while people tapped to referee papers try to get out of it whenever possible, by passing the papers off to colleagues, post-docs, or grad students.

Hassle aside, though, it is a critical part of what makes things work. It's what separates the Intelligent Design crowd and the Time Cube guy from actual scientists, and the process does work. In the handful of papers I've published, one referee caught an embarassing typo in an equation that had somehow slipped past the five authors, while another asked a very good question which later came up during my PhD defense (not an event which really changed the history of science, I suppose, but I felt a lot better for knowing the answer beforehand...). One of the papers I've refereed had a sign error in the very first equation, which changed everything that followed (they didn't make it into print). This knowledge of the importance of the task is pretty much the only thing that keeps the system working-- referees aren't paid for their time, and it's very much a thankless job, but I try not to turn down requests to referee papers unless I'm really not qualified to comment on the work in question, just because somebody has to do it, and it's an important part of scientific citizenship (basically, it's the science equivalent of jury duty).

The biggest problem with the system is that the criteria for publication can become ridiculously variable. One referee's idea of "important and of general interest to the physics community" may be another's "uninteresting crap." I hardly ever read Physical Review Letters without thinking "who the hell thought this was important enough to publish here?" and many an author has suffered rejection from a major journal only to look in the next issue and find essentially identical work with a slightly different spin. There are some safeguards built into the system to prevent political crap (authors can suggest referees, and request that some people not be given the paper to review, and journals try to avoid sending papers to close colleagues), but accusations that so-and-so spiked a competitor's work as a referee are a staple of ugly physics gossip. I've had the good fortune to work in a field where there's relatively little riding on any individual publication, but I've heard horror stories from other fields about authors deliberately leaving out or falsifying critical information to protect a competitive advantage or patent bid (Derek Lowe would be the guy to ask about that).

Still, for all its ungainly aspects, it's a far cry from the extreme Kuhnist/ post-whateverist picture of science as "socially constructed." There are ugly controversies from time to time, and a little bit of "grade inflation" as the standards for importance and general interest seem to be slipping, but by and large the system works. Blatantly incorrect work gets weeded out, basically correct but badly written work gets whipped into slightly better shape, and Science, as they say, Marches On. The proof is all around us-- peer review is essential to the progress of science, and the progress of science has led to the dizzying array of technological conveniences that make everyday life bearable.

To paraphrase a famous quote about democracy, the current system is the worst system except for every other method that you can think of. It's inelegant and inconvenient, and the subject of frequent hand-wringing pieces about how everything's falling apart, but somehow or another it hangs together well enough to make everything else work.

Posted at 10:31 AM | link | 7 comments

Sunday, July 07, 2002

Tell Us What You Really Think

"If you put a million monkeys without diapers in a room filled with word processors, surely it wouldn't be long before they produced a book better than this one."
--David Futrelle, reviewing Small Pieces Loosely Joined: A Unified Theory of the Web by David Weinberger, in the Washington Post's Book World.

Posted at 10:54 AM | link | no comments

The Path of Least Effort

The other comment I wanted to make regards a slightly earlier paragraph in the Den Beste article commented on below:

If there's any single factor which correlates most strongly with how well any given kid maximizes his potential (though not with how he does absolutely on achievement tests), it's in how much commitment his parents have to trying to make sure he does well in school. The biggest reason vouchers may well make a difference is that they may tend to motivate more parents to become more concerned about their kids education, instead of fatalistically accepting a terrible result.

That's actually a fairly reasonable point. I'm not sure I have any real confidence in this, though, based on what I hear from voucher proponents. In an ideal world, the effect would be to make parents take a greater interest in the education of their children, but I'm not convinced that the interest, in reality, will go beyond the absolute minimum level. What I really expect is more along the lines of "the public school sucks, we're sending you to Catholic school" followed by a resumption of the previous laissez-faire policies.

This is the real core of my objection to vouchers: it's just the latest in a long series of quick-fix schemes (assuming that it's not just a disguised subsidy for people already sending their kids to private schools, as Matthew Yglesias speculates (you'll need to scroll down to find the post, as his perma-links are all screwed up-- apparently, this is endemic to BlogSpot. If I figure out how to fix it on my end, I will, but you could do worse than to poke around his weblog for a while)). The goal of vouchers isn't actually an improvement in the education system, it's an improvement in the education system without any special effort on the part of parents and politicians. The central conceit of vouchers is that by running the public schools through the Magic Black Box of private enterprise and the free market, the system will effortlessly repair itself.

If you really believe that, I know some nice people in Nigeria who'd like to launder a trillion dollars through your bank account. Education is not a simple process, and fixing the school system is not a simple problem. Getting the best possible education for your child requires a degree of involvement significantly beyond the simple signing of tuition checks. It requires showing up at school for purposes other than picking up, dropping off, and bitching about grades or discipline. It requires sending a message to children that education is important, by taking an interest in what your child is doing in school, and by encouraging any interests they have. It requires proper funding for the schools, and seeing to it that the funding is allocated in a sensible manner-- doubling the athletic budget can't be expected to improve test scores, and adding four new administrative departments isn't likely to help, either.

With an appropriate level of parental involvement and encouragement, it's perfectly possible to get a good education even from a mediocre public school-- I'd count myself as an example of that. Were more parents to take a positive interest in the public school system, we wouldn't need to be having this argument.

It's also perfectly possible to send a child through the very best private schools the nation has to offer, and still end up with a complete chucklehead. Examples of this abound. Private schools without parental involvement are no panacea-- the central failure of the voucher movement is the assumption that they are.

Posted at 10:16 AM | link | no comments

Tenure: Threat or Menace?

Toward the end of a surprisingly sensible discussion of vouchers, Steven "Triage" Den Beste writes:

It also may induce a certain darwinism into the school system. It may, at last, be the answer to tenure. If the worst teachers are segregated into a school which fails, then they can be terminated when the school is closed outright without violating their tenure rights. Then the average competence of the teachers in the district rises. But it's an expensive, slow and extremely inefficient way to weed out the worst teachers. (IMHO, tenure is the absolute worst thing that ever happened to the educational system in the US at all levels, from kindergarten all the way up to post-graduate study. If everyone is paid according to seniority, and if no-one can ever be fired, what is to keep someone from just coasting?)

School vouchers is one of those issues I try fairly hard to avoid getting sucked into debating (with limited success). It's not that I don't have an opinion on the subject (as should be obvious from a previous post), but rather that my opinion is a bit too strong, and too bound up in personal stuff, for civil debate. My father just retired after thirty-two years of teaching sixth grade in a public school in a rural area of New York State, and for many of those years he was an active member of the teachers' union in the district. This means that the terms of the debate as set by most right-wing voucher proponents (that public schools are unremittingly awful, that teachers are venal and lazy, that teachers' unions are the servants of Satan) tend to strike me as personal insults, and I have to work hard not to get personally insulting in return.

With that warning out of the way, I have a couple of comments on Den Beste's comments above (which I'll split into two posts). In particular, I want to note that they reflect a couple of very common misconceptions about the tenure system and what it's for. (Full disclosure: Not only am I biased in favor of public school teachers in general, I'm also an assistant professor in a tenure-track job, so I have some interest in the system as it currently exists...)

First of all, tenure does not mean that it's simply impossible to fire anybody. It makes it more difficult to fire somebody, but it's possible to fire a tenured individual, given sufficient cause. Firing a tenured individual is a time-consuming process, and will almost certainly involve lawyers, but given careful documentation of the problems leading to the firing, it can be done. "We can't fire him, he's got tenure" is administrator-speak for "we don't want the hassle." The inviolability of tenure is as much a matter of administrative convenience as a structural reality.

But why have it at all, particularly in the public schools? The fact is that education, more than any other business, sometimes requires pissing people off. People generally seem to buy this idea on the college level, but it applies just as well at lower levels. I'm not just talking about McCarthyite political witch hunts, here-- try to imagine being a high-school biology teacher in the Bible Belt. The goal of education is to provide students with an accurate picture of the current state of our knowledge of the world, and that will sometimes require direct challenges to deeply held beliefs. Tenure protects biologists from being run off for failing to embrace young-Earth creationism, health teachers from being chased out for providing accurate sex-ed information, English teachers from being ridden out of town on a rail for assigning The Adventures of Huckleberry Finn.

It's also a protection for classroom discipline, particularly against parents. This may seem somewhat odd, given that most educators complain about a lack of parental involvement, but the real problem is often an excess of the wrong sort of parental involvement. Troublemaking students are often the spawn of parents who insist that little Johnny is an angel at home, and couldn't possibly be causing problems in school, so the teachers must be out to get him. Those people can already wield disproportionate power over gun-shy administrators by hinting at the possibility of lawsuits (I could generate a hundred megabytes worth of examples on this sort of thing without scratching the surface of my father's collection of anecdotes)-- if the teachers' jobs were also on the line, things would be much worse.

What about the issue of "coasting"? First of all, it's not true that tenure and "merit pay" are fundamentally incompatible-- the school where I presently work has both tenure for senior faculty and an extensive merit pay system. It's a very complicated process, requiring a detailed review of the activities of every professor over the course of a year, but everybody seems to agree that it works. Other than the difficulty of doing a fair review, and comparing across disciplines and grade levels, I'd have no objection to a system to reward good teachers beyond a seniority-based pay scale.

More importantly, though, it takes years to get tenure-- generally somewhere in the neighborhood of six or seven years. This is not a privilege that's granted lightly. Those are six or seven years during which the teacher doesn't get to "coast," six or seven years during which the school can evaluate them thoroughly to make sure they're competent, six or seven years during which they can be fired with relative ease should any problem come up.

If you can't manage to weed out the incompetents and people likely to start "coasting" during that span, well, you don't deserve to be running a McDonald's, let alone a public school. OK, fine, there's no guarantee that they won't go nuts or start "coasting" twenty years down the line. But while everybody can think of an example of a teacher who appeared to be just marking time until retirement, the majority of teachers don't do this. If nothing else, the nature of the job tends to drive out people who don't actually want to be there, doing what they're doing.

Posted at 10:07 AM | link | no comments

Saturday, July 06, 2002


For the benefit of anybody using BlogTracker (which I recommend), and wondering why nothing new has shown up from the last few republishings, I've just been fiddling around with the settings. I added a few more links to the sidebar (including this silly one, and cut down the number of posts on the front page, to speed loading for those suffering from dial-up access (accessing this weblog from my parents' place, over what turns out to be a 14.4 modem, was pretty painful...). There'll be new content, um... later.

Posted at 6:16 PM | link | no comments

Concert Review

My ears are still ringing a little as I sit down to type this, and I'm a little bleary-eyed owing to some major traffic delays on the way home from the show last night. I got tickets for the last night's Tom Petty and the Heartbreakers concert in Saratoga Springs (at the Saratoga Performing Arts Center (SPAC)) as a birthday present. The seats were in Row K, albeit way off on the side, so we were maybe a hundred feet from the stage, so it was a pretty damn good present. (We were also fifty from a speaker stack, hence the ringing ears... Kate, relentlessly sensible as always, wadded up Kleenex to make improvised earplugs for herself, but I stuck it out. It's nowhere near as bad as the last time I saw a show at SPAC (Guns 'n' Roses in 1991), when I was standing under the outdoor speakers for the lawn seats-- I thought I'd done some serious damage that time.)

Petty is Exhibit A when you set out to make the case that Rock-and/or-Roll is the greatest invention ever for ugly people. He's also one of those artists who raises the eternal question "How do you decide who qualifies to the the Name in 'Name and the Backing Bands'?"-- he's no great singer, and he's sort of an indifferent guitarist, so why's he the guy out in front?

The answer in Petty's case is relatively easy-- he's the guy who writes the songs. And while nobody's likely to accuse him of being Bob Dylan (having a voice that sounds like Dylan, yes, but not writing like Dylan), he's very, very good at what he does. They can easily fill two hours with a "Greatest Hits" set where almost everybody in the audience will know every word to every song, and most of the guitar noises, too. He's not especially innovative or pioneering, but he's a reliable author of three- or four-minute rock/pop songs with great hooks and catchy lyrics that sound like you know them by heart the first time you hear the song.

I can't claim to have been a fan all the way back to the beginning of their run, but Full Moon Fever is one of those records that's inextricably bound up with my memories of a specific time and place (in this case, my sophomore year in college, an identification which will have some of my readers rolling their eyes at my youth, while others will mistily recall singing "Free Fallin'" at junior high dances...). Not that it needs nostalgia value to make it work, mind-- it's a great album independent of when I first heard it-- but it was an inescapable part of the soundtrack for that year.

That album, and most of the rest of the band's catalog, is great sing-along-with-the-band material (indeed, in places, the vocals from the stage were superfluous). These aren't songs that have changed the course of human history, or anything, but they're catchy and fun, and there are a lot of them. In short, they're pretty much an ideal summer concert, and I was psyched to get to see them live.

It wasn't the greatest show I've ever seen (that honor would probably go to the Afghan Whigs at the 9:30 Club in DC, he says in a bid to recover a little High Fidelity street cred), but it was a good solid concert. They worked some new material in with the old hits (three songs from an album due in the fall, one of them very good, the other two not great), and generally tried to mix things up enough that it wasn't entirely a sing-along show (like, for example, the Jimmy Buffett show I saw (he says, throwing away what little street cred he regained by mentioning the Afghan Whigs)). They had an unfortunate tendency to try to stretch things out into ten-minute instrumental freak-outs, something which the songs don't really support, but I suspect that was pragmatic: their catalog consists of three-minute songs, and Tom sings them all-- without the occasional guitar freak-out, he'd have no voice at all by the end of the set.

They're a solid band, though, and slightly misguided instrumental excesses aside, they put on a good show. The songs we all knew the words to were played well, Petty knows the Important Rules of Rock Stage Patter (Rule 1: mentioning the name of the town you're in will get a big ovation, Rule 2: judicious use of the word "fuck" will also get a big ovation...) the new stuff was played with conviction, and they looked like they were having a good time. During the mostly-acoustic version of "Yer So Bad," I could see the drummer and bassist miming their parts to one another, and during the ten-minute improvised second verse to Van Morrison's "Gloria" the bassist and utility infielder (guitar, extra keyboards (Benmont Tench only having two hands), and backing vocals) could be seen speculating on just where he was going with this. They also knew how to close things out-- three-song encore, with "Free Fallin'" (wave your lighter in the air, and sing along), "Gloria", and "American Girl", then get right on the bus and get out of Dodge.

The opening act (traditionally relegated to the last paragraph or so) was Brian Setzer with a rockabilly trio (two guys with glasses and big hair reminiscent of Greg Proops from Whose Line Is It Anyway?), raising another of the Great Questions of rock concerts (besides "If it takes half an hour to tune the guitar, why don't you do that before we're all in our seats?"): "Doesn't it suck to be the opening act?" He played most of his set to a half-empty arena, which must be sort of frustrating to a guy who's twice had brief flirtations with actual pop stardom (then again, the opening act for the second leg of the tour is Jackson Browne, who's got to be even more frustrated with the whole thing). Setzer's one hell of a guitarist, though (another factor which hurt the Heartbreakers' instrumental freak-outs), even if he can't manage to duck-walk without looking like he's about to keel over, and he has a G. E. Smith level case of Guitar Face. I'm not the world's biggest rockabilly fan, but it's fun music in moderate doses, and Setzer and the Proopses play it with a lot of energy. He had most of the crowd on his side by the time he bowed out, and left to a nice ovation.

Posted at 12:29 PM | link | no comments

Thursday, July 04, 2002

Hey, Baby, It's the Fourth of July...

OK, Patrick Nielsen Hayden beat me to the X lyrics, but it's a great tune, so what the Hell...

I had a thought for a lengthy and witty piece to post today, but, well, it's really freakin' hot, and Kate and I decided we needed to get out of Schenectady for a while, so I'm writing this from Scenic Whitney Point, New York, where my parents enjoy the benefits of air conditioning, at the price of accessing the Internet through a 28.8 modem. Which means I'm just not going to be writing up a long and link-heavy weblog post. Odds are, there'll be nothing here tomorrow, either, as we'll be on the road again.

In lieu of actual content, here are a couple of links for your holiday enjoyment:

Joe Klein has a much more reasonable take on the American/ European split than most of the "blogosphere," and a few nice things about what makes this country great. (Found via Aaron Bergman.)

James Lileks sometimes manages to bug me by taking cheap shots at easy targets, but this is one of those pieces that reminds me why I read his stuff regularly.

And on that warm, fuzzy, and patriotic note, I'm off. Happy Fourth. I'll be back on Saturday.

Posted at 9:01 AM | link | no comments

Wednesday, July 03, 2002

Curiously, Fawn Hall was Temping at Arthur Anderson...

I'm going to be tiresomely political again, because, well, it takes less time to do that, and I have a lot of work to do today...

A few days back, Josh Marshall noted that the Republicans have adopted a new tactic to attempt to spin their way out of the current rash of dishonest-CEO scandals, quoting Steve Forbes saying:

Well, I think if you want to look at the tone of the '90s, it started right at the top, at the White House, where the attitude was anything goes. If you get caught, spin your way out of it. The only thing they didn't resist -- they could resist everything except temptation. So it started at the top.

Yes, that's right, it's all Clinton's fault. My first thought was that this sort of descent into self-parody was a bit much even for the Republicans-- OK, maybe David Horowitz or Alan Keyes could dribble out these sorts of statements, but surely they couldn't be stupid enough to try this on a large scale? But it seems to have gone out in the weekly memos of the Vast Right-Wing Conspiracy, with Andrew Sullivan weighing in with his version:

In some ways, they were deeply consonant with Bill Clinton's cultural ethos. When the president of the United States acted as if the only ethical criterion that mattered was what he could get away with, it's not entirely surprising that this attitude seeped outward into the general zeitgeist. I'm not saying Clinton was responsible for this corporate corruption - just that his administration was responsible for policing it and for setting the moral tone of the country.. And the boom began to spiral out of control at exactly the time that Clinton was fighting impeachment and desperately needed economic exuberance to insulate him from potential political suicide.

(Note the deft use of the pseudo-deflection "I'm not saying Clinton was responsible..." followed by further statements that, well, Clinton was responsible...)

Avedon Carol spots another one, too, from an episode of Politically Incorrect (Genevieve Wood is a talking head for the Family Research Council):

Genevieve: God forbid, while he's chasing interns and --

Bill: Thank you for falling into my trap one more time.

Tim: Look into my eyes, you will now be distracted by an affair.

Bill: Exactly.

Genevieve: No, no, no... The point is -- when you turn your back on the chief executive of the country and act like what he's doing behind closed doors is okay, what are you signaling to other people in the country? ...

(Found via Jim Henley)

Apparently, I've yet again underestimated the boundless loathing those on the right have for Bill Clinton personally (something I've never understood, for what little that's worth, but that's another topic). They certainly seem to view him as an all-purpose bogeyman, as sure to sway voters to their cause as a promise of bread, circuses, and lower taxes. Avedon Carol refers to this (quoting someone else, who got it from someone else-- do your own source-citing) as the "Tubesteak Messiah" phenomenon-- Clinton's penis is the cure for all Republican ills-- which is both amusing and disturbingly accurate.

The real shame here, though, is that they're not too far off. Not that I'm saying Clinton was responsible (really, do you think good conservative-type businessmen would take their lead from Clinton?), but I do believe that the tone for the current rash of executive malfeasance was set by a past occupant of the Oval Office (not the current one, either). I mean, let's look at the defenses offered by the principal figures in the Enron case: Ken Lay was "duped" by the senior managers, while Jeffrey Skilling "claimed not to know the details of Enron's problematic partnerships." Or look at the Worldcom case, where they're engaged in frantic buck-passing.

The true origin of this behavior has its roots farther back than the Clinton Administration. These people are following the spiritual lead of Ronald Reagan. I mean, think about it-- here we have the chief executives of major corporations disavowing all knowledge of the shady dealings carried on by their underlings, and putting the blame off onto subordinates and contractors (who will undoubtedly wriggle out on immunity deals and go on to profitable talk radio careers and maybe run for the Senate, in the manner of past high-profile felons).

Say what you will about Clinton, but nobody ever claimed he was ignorant of what went on in his White House. Not even his ardent defenders. If you want a cultural antecedent for the current round of CEO's using ignorance and gross incompetence as an excuse for their blatant malfeasance, you've got to go back to the Eighties, and put the blame on Ronald Reagan.

Posted at 9:20 AM | link | 1 comment

Tuesday, July 02, 2002

Geek Taxonomy

So, what, exactly, is it that I do for a living? (Other than come in to work every morning and respond to disgruntled emails about the grades I hand out, that is...). Depending on the context, I have a bunch of different answers to this question, depending on the degree of detail required. "College professor" or "physicist" seems to satisfy most people (who generally respond with some variant of "Eww. I hated that class."). A slightly more specific answer would be "I study atomic, molecular and optical physics" (I used to just say "atomic physics" but then people would assume I built bombs for a living...), though "Quantum Optics" is also a fairly accurate characterization of some of what I do, and sounds cooler. More specific yet would be "I study laser cooling of atoms and molecules" or even "I study ultra-cold collisions between atoms in laser-cooled samples." I've also worked in Bose-Einstein condensation, though that's not what I'm doing right at the moment.

Since most people are generally lost after "physicist" (and tend to have a somewhat distorted view of what physicists do-- white lab coats are less common than you might think), I'll save the explanations of quantum optics, laser cooling, and BEC for later posts, and give a quick run-down of the various sub-species of physicists. As with all academic disciplines, of course, the categories of physics are infinitely subdivided (and probably fractal in nature), but there are at least a handful of broad and generally recognized categories based on areas of study. In no particular order (and using the topic group headers favored by Physical Review Letters to remind myself of a few of them), these are:

Astrophysics and Cosmology: In a sense, this is the Department of Big Questions: Where did the Universe come from? Where is it going? How do planets/ stars/ galaxies/ clusters of galaxies form? What makes all the neat stuff we see through telescopes actually work?

Strictly speaking, Cosmology (dealing with the questions of the origin and ultimate fate of the whole Universe) is a somewhat separate field from Astrophysics (which deals with how the stuff in the Universe now works), but I'll lump them together here. I'm not entirely clear on where the line between "Astronomy" and "Astrophysics" is located, and as I know this is a subject which sometimes provokes ugly arguments, I won't attempt to draw one.

This is the sub-field most likely to produce amusingly obscure paper titles (my favorite, encountered while scanning the Table of Contents of Phys. Rev. Letters, was "Black Holes Have No Short Hair"), and also one of the most photogenic areas of physics. This stuff turns up in the New York Times science section with great regularity, usually illustrated with nifty pictures from the Hubble Telescope.

Elementary Particle Physics: These are the people with the massive particle colliders, and the whole zoo of quarks, leptons, mesons, muons, kaons, neutrinos, and all the rest. This is probably what most people think of when they think of physics. Experimental work in this field consists of getting a bunch of very small particles (generally protons), accelerating them up to a fair fraction of the speed of light, and slamming them into something else, to see what comes out. It's been compared to trying to figure out how a clock works by throwing it off a building and looking at the pieces that come out when it hits the ground.

On the theoretical side, it consists of some of the weirdest stuff you can imagine. In the regimes where these people work, even the fundamental forces are described in terms of the collisions and interactions of particles. All the fundamental forces start to merge together, the world actually exists in twenty-seven dimensions (give or take a few), and nothing much resembles reality as we know it. This is the domain of people who breathe the rarefied air of string theory (Aaron Bergman is a string theorist, and takes a whack at explaining some of it on his weblog), and judge theories as much by their mathematical elegance as by their correspondence to reality, simply because the experiments are too difficult to manage.

It may seem strange to list this field immediately after Cosmology (which deals with the study of Whopping Huge Things), but actually, the unimaginably small and the unimaginably large start to wrap into one another. If we can understand why the fundamental particles behave in the ways they do, that provides crucial information about how the Universe got here, and if we can figure out where the Universe came from and how the stuff we see formed after the Big Bang, we can maybe shed some light on why the particle zoo behaves the way it does. Think of this field as a sort of Adjunct Department of Big Questions (About Very Small Things).

This is also the Division of Very Large Collaborations. Since accelerators are so incredibly expensive, particle physicists have to team up into very large groups in order to amass the necessary funding. In idle moments, we used to check the author lists of particle physics papers to see if we could find ones with an author name for every letter of the alphabet ("X" and "Q" aren't as rare as you'd think, given the large numbers of Chinese physicists in these collaborations).

It's also the domain of the incredibly arrogant. Among scientists in general, physicists are regarded as arrogant, sneering at chemists and biologists because physics is more fundamental than those disciplines (Ernest Rutherford famously remarked "In science there is only physics, all the rest is stamp collecting."). Among physicists, the elementary particle crowd is regarded in much the same way-- they win all the "my work is more fundamental than yours" contests, and as a corollary, tend to regard their work as more important than anybody else's. Which leads to asking for six hundred gajillion dollars to build a new accelerator, and also to some foot-stamping hissy fits when they don't get the funding.

Nuclear Physics: A sort of intermediate regime between particle and atomic physics. They have to think about quarks and the like, but deal with them assembled into protons and neutrons. They deal with protons and neutrons assembled into nuclei, but don't worry about the rest of the atom, or interaction with other atoms. Experimental work in this field still involves accelerating things to very high speeds and slamming them into other things, but the collisions aren't quite as violent, and the accelerators aren't quite as expensive. The cutting-edge work in the field still involves large collaborations, though not quite as large.

In some ways, this is almost a forgotten field. It's far enough removed from everyday reality that it doesn't get press for producing useful things, but it's not as concerned with Big Questions as elementary particle physics, so it doesn't get press for answering Deep Questions. Other than the sub-set of nuclear physicists who do build bombs, you're unlikely to see these people in the New York Times.

Condensed Matter Physics: If you see a physicist wearing a white lab coat, he's either appearing in a movie, or he's a condensed matter physicist. This may be the largest single field of physics, and it's probably the most important in everyday terms.

Condensed matter physics involves the study of things which are, well, condensed: solids and liquids. It turns out to be easy to describe gases-- describe the properties of the individual particles, and make some statistical statements about the gas as a whole, and you're pretty much done. Solids and liquids, on the other hand, are much more difficult to describe. The properties of the individual atoms are still important, but they're greatly modified by having all those other atoms around, and every atom in the sample interacts quite strongly with its neighbors, all the time. This is a difficult situation to describe, and condensed matter physics has developed a wealth of techniques for dealing with these sorts of problems.

This is important, and profitable, because solids and liquids are the basis of much of modern technology. Condensed matter physicists study the properties of semiconductors (which include computer chips) and superconductors (which may be crucial for future technology), as well as materials science in general (building stronger materials, more flexible materials, lighter materials, or whatever).

Plasma Physics: Another regime associated with difficult problems, starting with "what is a plasma?" (Ask a dozen plasma physicists to define a plasma, you're likely to get fifteen different answers...) Very roughly speaking, a plasma is a gas of ionized particles. The individual components are free to move around as they like (as opposed to being bound into a solid or liquid), but they interact quite strongly with one another (meaning that the problem can't be cleanly separated into individual properties and statistical properties of the whole gas).

Plasma physics covers a wide range of topics, from plasma etching, to fluorescent light tubes, to interstellar gas clouds, to the composition and behavior of stars. Of course, the best-known application of plasma physics is the classic light bulb in a microwave, but only slightly less well known is the pursuit of fusion power generation. Electricity production by commercial fusion plants is no more than twenty years off, and expected to remain that way for the forseeable future.

Biophysics: This is more than just applying the equations of physics to determine exactly how much damage you're going to do to yourself when you fall from a high place. Biophysics is the study of the physical properties of biological systems-- how biological molecules arrange themselves, how electrical signals are transmitted between cells, how various life processes proceed on the atomic or molecular level.

This tends to shade into chemistry and biology (unsurprisingly), but it's a significant and growing field. Other biophysics type activities include developing new techniques for looking inside living things-- (N)MRI systems come from the medical side of biophysics research.

Atomic, Molecular, and Optical Physics: This is where I work. It's a very broad field, covering everything from laser development to quantum information processing, and from atomic spectroscopy to quantum state engineering. It's a fascinating field, but then I would say that, wouldn't I?

AMO Physics (as it's usually abbreviated) exists in a realm somewhere between plasma, condensed matter, and nuclear physics. We're aware of the nucleus of the atom, and it's important, but we're not overly concerned with the details. We sometimes deal with ions, but not too many of them, and we're generally happier if the atom has all the electrons it's supposed to. We deal with interactions between atoms, but not really large numbers of them at the same time (a well-known AMO joke (which may well have originated with Art Schawlow) runs "A diatomic molecule is a molecule with one atom too many.").

The systems we study are large enough to retain a clear connection to everyday reality, but small enough that quantum mechanics dominates their behavior-- another term which fairly accurately describes a lot of what goes on in AMO physics these days is "Quantum Optics," meaning that you need to treat both the atoms and the light field quantum-mechanically (the atoms behave like quantum-mechanical waves, the light waves are made up of particle-like photons). I've sometime jokingly referred to myself as a "quantum mechanic," which isn't too far off. The study of the physics of individual atoms is, after all, what gave rise to quantum mechanics in the first place.

This is also, generally, table-top physics. Experiments are conducted in smallish groups-- an AMO paper with more than five or six co-authors is rare-- and are cheap enough to be done in small labs on college campuses or the like (even though the cost of setting up a lab can be eye-popping-- I've spent in excess of $15,000 in the past three weeks-- this is small change on the scale of major science funding). It's also a fairly close community, at least on the "atomic" side (there are thousands of laser people)-- while the field itself covers a broad range of topics, it's not hard to keep track of the major players, and conferences in the field are large enough to be interesting but not so big as to be overwhelming.

I'm leaving out a number of categories, I'm sure (non-linear dynamics and statistical mechanics chief among them), but this is running rather long as it is, and the above will serve as a rough guide to the various classes of physics research (and the disparaging comments I make about other fields). So we'll stop here, and pick up at a later date with what, exactly, I do within the field of atomic physics.

Posted at 1:18 PM | link | 4 comments

Monday, July 01, 2002

There But For a Notable Lack of Genetically Engineered Super-Spiders Go I

Having been tediously political yesterday, I'll mix things up a little by talking about movies. In particular, Spider-man, which Kate and I went to last night (I'd seen it back in May, she hadn't seen it yet). This isn't a particularly new topic, as reviews of the movie ranging from the slightly star-struck to the fluorescently idiotic have already appeared on the web (I seem to recall James Lileks talking about it, too, but his archives aren't the most user-friendly you'll find...), but then I don't see that many movies in theaters, and might as well talk about this one.

One quick initial note: the ten minutes of commercials which preceded the actual film (not just trailers, but actual commercials) were a Bad Thing. If you want to sell ad time in the form of still images flashed on the screen before the stated show time, that's fine by me, but when the Appointed Time rolls around and the lights go down, I want to see the movie I paid eight bucks to see, not ten minutes of piss-poor advertising. I'd also like to ask for a general agreement that 1)the Scooby-Doo movie is an abomination, and 2) Austin Powers is played out. Thanks.

So, Spider-man. I was never a Comic Book Guy, so I can't speak to the movie's faithfulness to the original source material. As superhero movies go, though, it was probably the best I've seen since Tim Burton's Batman, though in a much different vein.

What makes the whole thing work is really Tobey Maguire's performance as a love-lorn dork. The CGI effects were actually a little cheesy-looking to me, and the story included all the usual plot-induced stupidity common to superhero stories (New York must have the thickest population in the entire world, if they can't figure out that Peter Parker is Spider-man. Does it not occur to Inspector Cramer and the boys to ask why the Green Goblin picked Mary Jane and Aunt May to terrorize?). What makes it work is that Parker is such a schlub, and Maguire plays it perfectly-- the enthusiasm for weird science trivia, the social awkwardness, the awkward kindnesses that never quite go where he wants with MJ. I recognize that character. Hell, I've been that guy. (Other than the whole thing with the spider, of course...) Watching him struggle and flounder in such a familiar way gives the story a depth and resonance that these things usually lack-- sure, Bruce Wayne had a tendency to look Troubled and brood a bit, but I've never been an orphaned billionaire.

They also did a great job with the small side details. Willem Dafoe chews scenery with the very best of them, and turns in a nice performance as the villain. They actually managed to find an actor who's slightly funny-looking in the right way to be believable as Dafoe's son. J. Jonah Jameson is great ("I resent that. Slander is spoken. In print, it's libel."), Jameson's newspaper is run out of the Flatiron building (I've been there...), and there's the obligatory cameo from Sam Raimi fixture Bruce Campbell.

(While I'm throwing out links from IMDB, let me note with mild incredulity that "Macho Man" Randy Savage's real name is apparently Randy Poffo. I guess that probably explains a lot...)

I'm not going to attempt to attach Deep Metaphorical Significance to this movie, and natter on about how it has Important Messages for these Difficult Times, because, well, that would be silly. It's a Summer Movie-- things Go Fast, they Blow Up, the Good Guy saves the day. Lights up, roll credits, drive home safely. Other than a sneaking suspicion that the scene where he poses briefly next to a billowing American flag atop a tall building was added to the movie in November, I can't say this movie made me think about September 11th at all.

Which is, after all, sort of the point of the whole enterprise.

Posted at 2:31 PM | link | no comments

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