“Who’s Been Deeply In Love?”

Via Jacob Levy, a little anecdote from a class at Princeton taught by Cornel West and Robert George.

Having touched upon such profound notions as free will, autonomy, and the alienation of man from God, the discussion of St. Augustine’s “Confessions” is humming along nicely when Cornel West *80, the Class of 1943 University Professor of Religion, poses the afternoon’s toughest question. “Who’s been deeply in love?” he asks, leaning so far forward in his chair that his goatee is almost touching the table as he looks around him at the rapt faces of 15 Princeton freshmen.

That’s not a question most students feel comfortable answering in a setting as public as a freshman seminar. There is silence until Dov Kaufmann, showing the sort of pluck you’d expect from a former first sergeant in the Israeli army, raises his hand, tentatively at first. If he is about to fall into a trap, it will be particularly awkward to climb out, since the climbing will have to be done in front of 14 curious classmates. But Kaufmann is spared having to make any further confessions when West steps in and rescues him: “Now, this brother knows!” he exclaims. “You fall in love, you stop looking at those other girls. They became uninteresting.”

“Now, let’s not look too closely,” laughs Robert George, the McCormick Professor of Jurisprudence, who teaches the course with West and is sitting next to him.

But West is not to be deterred. He wants to bring the point around to the freedom that comes, paradoxically, from surrender. “When you fell in love, you became free,” he tells Kaufmann. “Before that, on Saturday night, you’d be looking at all the girls. You were a slave.”

It is a witty eureka! moment, one that deftly links Augustine’s 1,600-year-old autobiography to life on the Princeton campus today. Kaufmann remembers it fondly: “Professor West seemed to maybe have some hidden story of his own, because he was really smiling too,” he says. “I thought that was neat.”

A lot of college classes present intimidating vistas of endless drudgery, but occasionally you get ones that really, truly, make you think, deep down into your core. Those are magical, and are why the undergraduate experience can be like nothing else in your life. Celebrity professors are not required; I certainly had several such experiences at Villanova.

The news hook for the story is actually not “here’s a cool class,” but “look at these ideological opposites co-teaching a course.” West (who quit Harvard after clashing with Larry Summers) is a charismatic leftist, while George is an influential conservative. But they apparently have a good time coming together with students to engage seriously with Great Ideas, and have struck up a friendship “based on a shared passion for intellectual inquiry.”

“Who’s Been Deeply In Love?” Read More »

6 Comments

Latest Declamations about the Arrow of Time

Here are the slides from the physics colloquium I gave at UC Santa Cruz last week, entitled “Why is the Past Different from the Future? The Origin of the Universe and the Arrow of Time.” (Also in pdf.)

Time Colloquium

The real reason I’m sharing this with you is because this talk provoked one of the best responses I’ve ever received, which the provokee felt moved to share with me:

Finally, the magnitude of the entropy of the universe as a function of time is a very interesting problem for cosmology, but to suggest that a law of physics depends on it is sheer nonsense. Carroll’s statement that the second law owes its existence to cosmology is one of the dummest [sic] remarks I heard in any of our physics colloquia, apart from [redacted]’s earlier remarks about consciousness in quantum mechanics. I am astounded that physicists in the audience always listen politely to such nonsense. Afterwards, I had dinner with some graduate students who readily understood my objections, but Carroll remained adamant.

My powers of persuasion are apparently not always fully efficacious.

Also, that marvelous illustration of entropy in the bottom right of the above slide? Alan Guth’s office.

Update: Originally added as a comment, but I’m moving it up here–

The point of the “objection” is extremely simple, as is the reason why it is irrelevant. Suppose we had a thermodynamic system, described by certain macroscopic variables, not quite in equilibrium. Suppose further that we chose a random microstate compatible with the macroscopic variables (as you do, for example, in a numerical simulation). Then, following the evolution of that microstate into the future, it is overwhelmingly likely that the entropy will increase. Voila, we have “derived” the Second Law.

However, it is also overwhelmingly likely that evolving that microstate into the past will lead to an increase in entropy. Which is not true of the universe in which we live. So the above exercise, while it gets the right answer for the future, is not actually “right,” if what we care about is describing the real world. Which I do. If we want to understand the distribution function on microstates that is actually true, we need to impose a low-entropy condition in the past; there is no way to get it from purely time-symmetric assumptions.

Boltzmann’s H-theorem, while interesting and important, is even worse. It makes an assumption that is not true (molecular chaos) to reach a conclusion that is not true (the entropy is certain, not just likely, to increase toward the future — and also to the past).

The nice thing about stat mech is that almost any distribution function will work to derive the Second Law, as long as you don’t put some constraints on the future state. That’s why textbook stat mech does a perfectly good job without talking about the Big Bang. But if you want to describe why the Second Law actually works in the real world in which we actually live, cosmology inevitably comes into play.

Latest Declamations about the Arrow of Time Read More »

75 Comments

Richard Rorty

Richard Rorty Richard Rorty has passed away. He was arguably the most well-known living American philosopher, not least of which because he was a wonderful communicator; see Jacob Levy’s appreciation of his rhetorical skills.

Intellectually, Rorty was hard to pin down; while he was most closely identified with the American pragmatist tradition of Dewey and Peirce, he was trained as a hard-core analytic philosopher, and later became heavily influenced both by Wittgenstein and by continental/”postmodern” philosophy. So he managed to annoy everybody, basically. But his real project was to take seriously radical critiques of meaning and truth while simultaneously offering a positive prospect for morality and human living. Which is a good project to have, I think.

Wikipedia has a representative quote from Contingency, Irony, and Solidarity, in which Rorty spells out his view of a good “ironist”:

(1) She has radical and continuing doubts about the final vocabulary she currently uses, because she has been impressed by other vocabularies, vocabularies taken as final by people or books she has encountered; (2) she realizes that argument phrased in her present vocabulary can neither underwrite nor dissolve these doubts; (3) insofar as she philosophizes about her situation, she does not think that her vocabulary is closer to reality than others, that it is in touch with a power not herself.

As physicists go, I’m more sympathetic to postmodernism than most. (Who are, you know, not very sympathetic.) What I really think is that people who think carefully about science and people who think carefully about the social construction of truth would have a lot to learn from each other, if they would approach each other’s concerns and insights in good faith, which is hard to do.

When Rorty talks about “final vocabularies” in the quote above, he’s not really thinking of “quantum field theory” or “general relativity” or even “the scientific method,” although they would arguably be legitimate examples. He’s thinking of doctrines of religion or morality or politics or ethics or aesthetics that we use to judge good and bad and right and wrong in our lives. These are areas in which such vocabularies truly are contingent, and unpacking our presuppositions about their finality is a useful practice.

Science is different. To do science, we presume the existence of a “real world” that is “out there” and follows a set of rules and patterns that are completely independent of whatever actions we humans may be taking, including our actions of conceptualizing that real world. Questions of good and bad and right and wrong are not like that; their subject matter is our judgments themselves, which are subject to interrogation and ultimately to alteration. Right and wrong are not out there in the world to be probed and described; we create them through various human mechanisms. A scientist cannot consistently hold radical doubts about the nature of the real world.

On the other hand — and this is the part that, I think, scientists consistently miss — we certainly can hold radical doubts about the vocabulary with which we as scientists describe that real world. In fact, when pressed in other contexts, we are the first to insist that scientific theories are always useful but limited approximations, capturing some part of reality but certainly not the whole. Furthermore, even experimental data do not provide any unmediated glimpse of reality; not only are there error bars, but there are also the irreducible theory-laden choices about which data to collect, and how to fit them into our frameworks. These are commonplace scientific truisms, but they are also deep postmodern insights.

In my personal intellectual utopia, postmodernists would appreciate how science differs from morality and ethics and aesthetics by the ontological independence of its subject matter, while scientists would appreciate how there is a lot we have yet to quite understand about how we use language and evidence in an ultimately contingent way. Just as Rorty wanted to make ironic skepticism compatible with human solidarity, I’d like to see suspicion toward final vocabularies made compatible with the undeniable truth of scientific progress.

Or am I just being ironic?

More: Mixing Memory has a list of other blog posts on Rorty; Continental Philosophy has a collection of links and a recent video.

Richard Rorty Read More »

25 Comments

Downtime

Yeah, we know, you can’t read the blog. We are once again the victim of frequent “This Account Has Exceeded Its CPU Quota” errors. Apparently we have a bunch of slow mysql queries, and need to optimize our indices. Which might be very straightforward, if any of us knew what those words meant. Dammit, Jim, I’m a doctor, not a database manager!

Here is the kind of error message we’re getting:

# Sat Jun 9 01:23:22 2007
# Query_time: 4 Lock_time: 0 Rows_sent: 27359 Rows_examined: 83792
SELECT
comment_post_ID, post_title
FROM (wp_comments LEFT JOIN wp_posts ON (comment_post_ID = ID))
WHERE comment_approved = ‘1’
AND comment_type NOT LIKE ‘%pingback%’ AND comment_type NOT LIKE ‘%trackback%’
ORDER BY comment_date DESC

Full of important information, I’m sure, but I have no idea what it means or how to fix it. We might just change web hosts as a way to sidestep the problem, but that sounds like work. Any other suggestions?

Update: The particular problem mentioned here has been traced to a particular plugin and fixed. We’ve eliminated all of the noticeably slow mysql queries, but the problem persists. Once in a while an apparently ordinary request (“GET” a certain page, for example) takes 30 seconds, for no discernible reason. We’ve optimized the database, and even created some new indices, although I’m not even sure if that helps or hurts things. Maybe it will fix itself.

Downtime Read More »

21 Comments

The Enlightenment Marches On

Kieran Healy at Crooked Timber notes with approval that more than 83% of Americans now think that interracial dating is acceptable. Now, some of you might be thinking, “Hey, that means that there’s still 17% of Americans that think interracial dating is not okay.” Well, yes. But everything is relative. Apparently the folks at the General Social Survey, just for kicks, decided to ask Americans to come clean about their feelings toward heliocentrism. As it turns out, about 18% of Americans are in the “Sun moves around the Earth” camp. A full 8% prudently declined to have an opinion, leaving only 74% to go along with Copernicus. (Of which, nearly three-quarters understood that it took a year for this process to unfold.) So, you take what you can get.

I hope our blog didn’t confuse them.

The Enlightenment Marches On Read More »

35 Comments

Open Thread

Everyone is too busy to blog this week. But I’ll point you to my favorite quotes from Ezra Klein’s liveblogging of last night’s Republican presidential debate:

  • 7:15 If this election is to be decided on ties, Ron Paul is totally going to win. And Sam Brownback will be executed.
  • 7:41 Does anybody really believe religion is a “very important” part of Giuliani’s life? He seems like the type who would make holy water sizzle.
  • 7:47 McCain thinks Americans should be exposed to “all theories.” All children will now go to school until the end of time.

Talk amongst yourselves, as long as it doesn’t involve Paris Hilton.

Open Thread Read More »

34 Comments

It Does Matter What People Think About How the World Works

It was an embarrassing moment in the first Republican presidential debate when the participants were asked, “Does anyone not believe in evolution?”, and three candidates — Sam Brownback, Tom Tancredo, and Mike Huckabee — raised their hands. Embarrassing for those three, obviously, but also for the Republican party, in which they are far from unrepresentative, and for the United States, that anyone would even think to ask such a question of serious candidates for the highest office in the land.

One of the candidates, Sam Brownback, felt the need to amplify his position in a New York Times op-ed piece. He appeals to many favorite creationist weasel words, invoking the distinction between “microevolution” and “macroevolution,” but tries not to come off as completely anti-science. Nevertheless, the heart of his argument is stated clearly at the end of the piece:

While no stone should be left unturned in seeking to discover the nature of man’s origins, we can say with conviction that we know with certainty at least part of the outcome. Man was not an accident and reflects an image and likeness unique in the created order. Those aspects of evolutionary theory compatible with this truth are a welcome addition to human knowledge. Aspects of these theories that undermine this truth, however, should be firmly rejected as an atheistic theology posing as science.

Without hesitation, I am happy to raise my hand to that.

In our scientific understanding of the universe, man does not reflect an image and likeness unique in the created order. Humanity arose by the same process of natural selection as all the other species. Calling it “atheistic theology” doesn’t change the fact that it’s how the world works, according to science.

Eugene Volokh asks whether it really matters what a presidential candidate thinks about human evolution. He tentatively argues that yes, it does matter, but I think it’s a lot more cut and dried (but still interesting) than he makes it out to be. There are really two issues: first, has science established beyond reasonable doubt that humans evolved purely through natural selection, and second, if it has, does it matter whether a presidential candidate rejects that particular scientific understanding? Yes, and yes. But the intriguing follow-up is: what about other untrue beliefs that candidates might have?

In case you haven’t heard: yes, science has established beyond reasonable doubt that humans evolved via natural selection. Volokh confuses the issue by asking whether Brownback’s beliefs are “provably false,” and (correctly) concluding that they are not. But scientific propositions are never provably true or false; that’s not how science works. We accumulate more and more evidence in favor of one theory and against all competitors, until we reach a point where the only people left who refuse to accept the theory are cranks. Natural selection is firmly in that category; there is no scientific controversy about its truth. To draw a somewhat subtle distinction: I personally do not think that belief in an ineffable touchy-feely Aristotelian Unmoved Mover kind of God is in the crank domain. I think it’s wrong, and based on a set of deep philosophical and scientific mistakes, but not crackpottery in the same way that attributing crucial aspects of human evolution to a meddlesome anthropomorphic Designer would be.

Which brings us to the second and more interesting question, of whether this particular kind of mistaken belief should bear on one’s fitness as a presidential candidate. I think it does, for a reason that our experience with the Bush administration has made especially relevant. Denial of the standard scientific explanation for the origin of human beings is a particularly dangerous kind of mistake: one based on a decision to put aside evidence and deduction in favor of wishful thinking, and an insistence on a picture of the universe that flatters ourselves. The kind of reasoning that leads one to conclude that we can’t explain human evolution without invoking a meddlesome God is the same kind of reasoning that makes people think that cutting taxes will decrease the federal deficit, or that the people of Iraq would throw candy and greet us as liberators. (I’m sure that liberals are just as susceptible to such a fallacy, but it’s the conservative versions that are currently getting us in such a mess.) It’s a refusal to take reality at face value, in favor of a picture that conforms to what we want to be true.

The interesting part of Volokh’s question is, what about the Virgin Birth? By ordinary scientific standards, belief that Jesus had a mother but not a father is at least as unlikely as belief in a divine role in human evolution. Should we hold such a belief against presidential candidates?

That’s actually a really tough question, and I’m going to weasel out of it a bit myself. On the one hand, everything I just said about human origins applies just as well to the Virgin Birth — belief in it is dramatically non-scientific, and prompted largely by exactly the kind of mythological self-flattery that leads to skepticism about the efficacy of natural selection. In other words, belief in the Virgin Birth is exactly as “wrong” as belief in creationism. So I can certainly appreciate the argument for holding such beliefs against presidential candidates.

On the other hand, I think the status of these two questions are different, in at least two important ways. First is the role of each question as a foundational part of modern science. Evolution is a crucial ingredient in how we understand Nature and our place in it; to deny it is to deny a bedrock principle of science. The birth of Jesus, on the other hand, is a localized miracle that nominally happened a long time ago. If someone wants to believe in that particular isolated violation of the laws of nature, I won’t go along with them, but it doesn’t bother me nearly as much as denying natural selection as the correct explanation for the origin of human beings.

Second, the status of evolution has taken on a unique political role in our culture. Evolution is the particular part of science which has come under the most concerted attack by the forces of irrationality, who have attempted to undermine science by calling into question the teaching of evolution in public schools. This is now a political and cultural question, not just a scientific one; it’s no accident that debates over creationism and intelligent design are essentially confined to the United States (although sadly spreading). For a presidential candidate to take a public stance against evolution by raising his hand at a televised debate is a profoundly political act, allying that candidate with the forces of superstition against the forces of science. The question of the Virgin Birth just doesn’t have that status.

Happily, I was not really hesitating over whether to throw my support to Brownback, Huckabee, or Tancredo, so the question is somewhat academic for me. But I do believe, in the face of all the contrary evidence provided by the current Administration and its die-hard supporters, in the existence of intelligent and principled conservatives who might be in favor of limited government and perhaps an aggressive foreign policy, but would like to try to base their decisions on evidence and reason. Those people are going to have to make some tough choices; the modern Republican party has chosen to ally itself with people who don’t believe in the real world, and that choice is going to have consequences.

It Does Matter What People Think About How the World Works Read More »

65 Comments

Follow the Bouncing Neutron

Stefan at Backreaction has a great post up about measuring the quantum state of a bouncing neutron. If you drop a basketball, it falls freely along a geodesic in the curved spacetime around the Earth, until it comes in contact with the floor; at that point it bounces back up and falls freely again. The cycle repeats, although basketballs come with dissipation (otherwise you wouldn’t hear them bounce), so the bounces gradually lose altitude, unless you impart some force to the ball by dribbling.

Well, the same goes for neutrons, except that there isn’t any appreciable dissipation, so the neutrons just keep bouncing. And neutrons are subatomic particles, so we can imagine observing not just their classical position, but their quantum wavefunction! And that’s what people like Valery Nesvizhevsky have been able to do, using interferometry. I won’t explain the details, since Stefan has already done it better than I could, and you should read it there.

Quantized Neutrons

So there’s both “quantum” and “gravity” involved here, although not “quantum gravity.” The neutron is quantized, but the effects are just those of a classical background gravitational field. (Quantum gravity would become involved if you measured the gravitational field caused by the neutron, and that’s a bit harder.) But still, you’re observing the effects of spacetime curvature on the wavefunction of a subatomic particle, which is pretty neat. And it’s plausible that someday measurements could improve enough that you’re measuring Newton’s inverse-square law for gravity at very small scales, which is relevant for constraining all sorts of theoretical models. And I’m guessing that you could even test the Equivalence Principle, if you could do the same exact experiment with some other kind of neutral particle (a hydrogen atom, maybe?). But really, it’s just cool, and that’s its own reward.

Also from Backreaction I learned that the current mood of the internet is:

The current mood of the Internet at www.imood.com

It’s good to be updated on these things.

Follow the Bouncing Neutron Read More »

20 Comments

Congratulations to Iggy!

The latest young cosmologist to officially ascend to the inner sanctum of the ivory tower is Ignacy Sawicki, who successfully defended his Ph.D. thesis yesterday. (Some of us are less grudging with our congratulations than others.) I swooped into Chicago for the event, then swooped right back to LA last night, from which I will swoop over to Washington DC later today. Many miles were accumulated, but I had to be there for the defense, otherwise Wayne Hu totally would have claimed credit for being Iggy’s advisor, just because they wrote more papers together.

In just a few short years Iggy has written an impressive series of in-depth papers on the possibility of modifying general relativity to explain the acceleration of the universe.

  • Cosmological structure evolution and CMB anisotropies in DGP braneworlds, with S.M. Carroll, astro-ph/0510364.
  • Near-Horizon Solution for DGP Perturbations, with Y.-S. Song and W. Hu, astro-ph/0606285.
  • Large-Scale Tests of the DGP Model, with Y.-S. Song and W. Hu, astro-ph/0606286.
  • Modified-Source Gravity and Cosmological Structure Formation, with S.M. Carroll, A. Silvestri, and M. Trodden, astro-ph/0607458.
  • The Large Scale Structure of f(R) Gravity, with Y.-S. Song and W. Hu, astro-ph/0610532.
  • Stability of Cosmological Solution in f(R) Models of Gravity, with W. Hu, astro-ph/0702278.
  • Models of f(R) Cosmic Acceleration that Evade Solar-System Tests, with W. Hu, arXiv:0705.1158.

In the Fall he’ll be taking his post-Einstein sensibilities to the socialist enclave in Greenwich Village, where such things are considered politically acceptable. Congratulations!

Congratulations to Iggy! Read More »

9 Comments

The Physics of Christianity

It’s only with some reluctance that I even mention Frank Tipler’s latest book, The Physics of Christianity. But people keep telling me about it, so, it’s like, my duty or something.

Now, I’m all in favor of writing about the physics of imaginary things; it can be a very enlightening exercise to compare the laws of the actual world to ones that we make up for purposes of fiction. And The Physics of Christianity is such an obvious title that you knew someone would write such a book eventually. And Frank Tipler, in his youth, did some pioneering research on closed timelike curves in general relativity, so he has credentials as an honest physicist.

But, if there remains an interesting book to be written about the physics of Christianity, this isn’t it. And I say that in full confidence, not having actually read the book. Usually I like to defer judgment about crazy-sounding books that I haven’t even looked at, but in this case I’ll make an exception. Reviews by Vic Stenger or Lawrence Krauss tell you everything you need to know. From Lawrence’s review:

As a collection of half-truths and exaggerations, I am tempted to describe Tipler’s new book as nonsense – but that would be unfair to the concept of nonsense…

Tipler, for example, claims that the standard model of particle physics is complete and exact. It isn’t. He claims that we have a clear and consistent theory of quantum gravity. We don’t. He claims that the universe must recollapse. It doesn’t have to, and all evidence thus far suggests that it won’t. He argues that we understand the nature of dark energy. We don’t. He argues that we know why there is more matter than antimatter in the universe. We don’t. I could go on, but you get the point…

[Tipler] argues that the resurrection of Jesus occurred when the atoms in his body spontaneously decayed into neutrinos and antineutrinos, which later converted back into atoms to reconstitute him.

Not much motivation for reading further than that. I’ve said many times (even if people don’t believe me) that I have a great deal of respect for intelligent and thoughtful religious people, even if I disagree with them on some deep truths about the universe. But man, those people don’t seem to get a lot of press, do they? The crazy stuff is much bigger box office, which perhaps is not a surprise.

Neutrinos and antineutrinos! That kills me. Everyone knows that Jesus shifted through the extra dimensions onto another brane, where he chilled for three days before coming back.

The Physics of Christianity Read More »

59 Comments
Scroll to Top