… not yet released, but we’ll find out in just a bit. 2:00 p.m. Pacific time, to be exact.
Last week we mongered the rumor that the CDMS experiment was going to announce an exciting new result soon — and that time is now. (My guess remains: some interesting data that falls well short of “we’ve discovered dark matter!”) If you’d like to watch the talks online, here you go:
Further bulletins as events warrant.
In one of the comments to Daniel’s post on the stolen climate emails, techskeptic points to a wonderful chart at Information is Beautiful. The author did a great deal of gruntwork to lay out the various arguments of “The Global Warming Skeptics” vs. “The Scientific Consensus.” As far as I can tell, it’s a legitimately balanced view of both sides, complete with citations. If you’re confused about the various issues and accusations being bandied back and forth, there are worse places to start. This is a small piece of the full chart.
Of course, there is no such thing as a purely objective and judgment-free presentation of data, no matter how scrupulously the data itself may be collected; if nothing else, we make choices about what data to present. And a side-by-side comparison chart like this can’t help but give a slightly misleading impression of the relative merits of the arguments, by putting the conclusions of an overwhelming majority of honest scientists up against the arguments of a fringe collection of politically-motivated activists. But it’s certainly good to see the actual issues arrayed in point-counterpoint format.
Still, there remains a somewhat intractable problem: when people are arguing about issues that necessarily require expert knowledge that not everyone can possibly take the time to acquire for themselves, how do we make judgments about who to believe?
This problem has been brought home by the incredibly depressing news that James Randi has come out in favor of global-warming denialism (via PZ Myers). Randi is generally a hero among fans of reason and skepticism, so it’s especially embarrassing to see how incredibly weak his reasoning is here. It basically amounts to: “The climate is complicated. And scientists don’t know everything. And I admit I don’t know much about the field. Therefore … we have good reason to distrust the overwhelming majority of experts!” Why Randi chose not to apply his vaunted powers of skepticism to the motivations behind the denialists remains a mystery.
This gets to the heart of why I’ve always been skeptical of the valorization of “skepticism.” I don’t want to be skeptical for the sake of being skeptical — I want to be right. To maximize my chances of being right, I will try to collect what information I can and evaluate it rationally. But part of that information has to include the nature of the people making arguments on either side of a debate. If one side consists of scientists who have spent years trying to understand a complicated system, and the other is a ragtag collection of individuals with perfectly obvious vested interests in the outcome, it makes sense to evaluate their claims accordingly.
By all means, we should apply our own powers of reason to every interesting problem. But when our reasoning leads to some conclusion at odds with the apparent consensus of a lot of smart people who seem to know what they’re talking about — whether it’s on the nature of dark energy, the best way to quantize gravity, the most effective route to health care reform, or the state of the environment — the burden is on us to understand the nature of that difference and try to reconcile it, not to take refuge in “experts don’t know everything” and related anti-intellectual piffle.
Last week I Twittered/Facebooked some provocative results from a poll of philosophers. In particular, this little tidbit:
Teletransporter (new matter): survival or death?
Accept or lean toward: survival 337 / 931 (36.1%) Other 304 / 931 (32.6%) Accept or lean toward: death 290 / 931 (31.1%)
Yes, that’s all the detail presented in the question: “Teletransporter (new matter): survival or death?” As a professional philosopher, you’re supposed to be familiar with the issue, which I reconstruct as follows. Imagine that someone has invented a working teleportation device. You step in the box, lights flash and sparks fly, and “you” rematerialize in another box, exactly the same in every way, but constructed out of a completely new collection of atoms. The original version of you is destroyed. Did you die? (And then, what if a million years passed in between the two events?)
It would probably be annoying to real philosophers, but I personally put this question in the category of “Not that hard.” And I would phrase my answer as: “Who cares?” What we should care about is how well the teleporter actually works — is the reconstructed person really in exactly the same quantum state as the original one was in? Same memories, feelings, etc? That’s an interesting technology question.
But there’s no interesting question associated with “Did you really die when you were teleported?”, or “Are you really the same person after being teleported?” These are just bad questions. They assume a certain way of looking at the world that ceases to be useful once we’ve invented teleportation. Namely, they assume that there’s a certain “essence of you-ness” that is (somehow) associated with your physical body and continues through time. That’s a perfectly sensible way of talking in the real world, where we don’t have access to duplicator devices or transporter machines. But if we did, that conception would no longer be very useful. There is a person who stepped into the first box, and a person who stepped out of the second box, and obviously they have a lot in common. But to sit down and demand that we decide whether they are “really” the same person is just a waste of time — there is no such “really.”
Which isn’t to say there aren’t interesting questions along these lines, but they are operational questions — how should I actually act, or what should I actually expect to happen, in these situations? — rather than arid metaphysical ones. What if you murdered someone, and then teleported — would the reconstructed person still be guilty of murder? That’s not quite the right question, because it still relies on the slippery essence of continuous personhood, but there’s a closely related sensible question — should we treat the reconstructed person as if they had committed murder? And it seems to me that the answer is clearly “yes” — whatever good reasons we had for treating the pre-teleportation person in a certain way, those reasons should still apply to the post-teleportation person.
The issue of duplication seems much thornier to me than the issue of teleportation. If someone made an exact copy of a known murderer, should we treat both the original and the copy as murderers? (I vote “yes.”) Fine, but what about the view from the inside? Let’s say you have an offer to get paid $100 if you let yourself be copied, with the proviso that after being copied one of the two of you will randomly be chosen for immediate painless execution. Do you take that deal?
I think problems like that are legitimately interesting, although to a great extent their mystery relies on the inadequacy of our conceptions of death. Most of us don’t want to die, at least not right away. But if we did die, we’d be gone, and wouldn’t have any wants or desires any more — but it’s very hard to consistently reason that way. Note that if we replaced “immediate painless execution” with “prolonged torture,” it seems like a much more straightforward question.
This showed up in our long-ago discussion of the quantum suicide experiment. In the many-worlds interpretation of quantum mechanics, you can make measurements that split the wave function of the universe into distinct branches. In some sense, then, you really do have a duplicator machine — it’s just that the whole universe gets duplicated, not just you. Some folks have tried to argue against this idea by pushing adherents into a logical cul de sac. You shouldn’t (to make a long story short) be averse to bargains that leave you dead with large probability, as long as there exist branches of the wave function where you are alive and flourishing — after all, in the branches where you are dead you don’t care any more, right?
My point in that earlier post — a point I somehow managed to completely obscure — was that these are misleading thought experiments, because very few of us would take seriously the corresponding classical suicide experiment. “Here, I’ll flip a coin, and give you $100 if it’s heads and shoot you instantly dead if it’s tails. Deal?” Very little temptation to take that offer. But the logic is essentially the same — if you’re dead you don’t care, right? (For purposes of these thought experiments we always assume you have no friends or loved ones who would miss you; it’s just part of the philosophical game, not a comment on your actual social situation.)
At some point in thinking about the many-worlds interpretation, issues like this inevitably do come up. That’s what David Albert and I talked about a bit on Bloggingheads. There might be a certain measurement that yields result A 10% of the time, and result B 90% of the time. But in the MWI, the measurement splits the universe into two branches, and you end up either in the branch where you saw A or the branch where you saw B. What does it mean to say that you had a “10% chance of measuring A”? You either did or you didn’t — there is no ensemble of millions of you all doing the same experiment. People have made progress on these questions — here’s a talk by David Wallace on his work with David Deutsch in attacking this problem. (Don’t ask me why everyone who thinks about these issues is named “David.”) I haven’t ever looked at this work closely enough to have an informed opinion.
All I know is that being able to teleport around would be really cool.
Here are the opening sentences of Chapter Five of my book:
When most people hear “scientist,” they think “Einstein.” Albert Einstein is an iconic figure; not many theoretical physicists attain a level of celebrity where their likeness appears regularly on T-shirts. But it’s an intimidating, distant celebrity. Unlike, say, Tiger Woods, the precise achievements that Einstein is actually famous for remain somewhat mysterious to many people who would easily recognize his name.
And now we can add, “and some achievements should really stay mysterious, thanks just the same.”
We occasionally joke about the looming robot menace, but seriously. Discoblog has picked out the Niftiest Robots of 2009, but “Scariest” would have been an equally appropriate appellation.
Yes, there is a robot that crawls around inside your colon, not to mention a Japanese emobot, but the one I would least like to meet in a dark alley is Chembot. It’s a blob-shaped thing that uses jamming in granular materials to make a robot that can alter its shape.
Still pretty primitive, but you can see where we’re headed here. Don’t say we didn’t warn you.
All the physics blogosphere is abuzz about rumors that the CDMS experiment might have collected evidence for the direct detection of dark matter, and is going to announce their results on December 18. The original source was Resonaances, where you can read the basic story; see also New Scientist. It’s to the point where it’s more suspicious if we don’t mention it than if we do, so here you are.
Not too much point in speculating — we’ll find out next week! There was some misplaced excitement about a Nature paper, but it is true that CDMS has scheduled simultaneous talks at CERN, Fermilab, SLAC, and elsewhere. Steinn did the citizen-journalist detective work and dug up the abstract for Priscilla Cushman’s talk at CERN:
I will present new results from the recent blind analysis of 612-kg days (before cuts) of data using the CDMS germanium detectors at Soudan. CDMS uses ionization and athermal phonon signals to discriminate between candidate (nuclear recoil) and background (electron recoil) events in Ge crystals cooled to ~ 50 mK. Timing, yield and position information allows us to tune our expected background leakage into the signal region to 0.5 events. I will report on what we saw when we “opened the box”, whether we have seen WIMPs or not, and implications for future dark matter direct experiments.
It would seem unlikely to me that CDMS would be able to announce a cut-and-dried discovery of dark matter; that would require collecting an awful lot of data. (But what do I know?) It’s more plausible that they would see some kind of provocative signal, but without quite enough significance to be definitive. With many different competing experiments, several of which have been working for quite some time now, it seems like the kind of result that you would gradually sneak up on, rather than dramatically capture in one fell swoop. Or maybe they’re just updating us on their best limits, and some rumor-mongering has spiraled a bit out of control. We’ll see.
The Hubble Space Telescope has come out with a new ultra deep field image — this one in the near-infrared, taken with the Wide Field Camera 3 (WFC3) that was installed on the latest servicing mission. Colors are fake (obviously, unless you have infrared vision), but the spirit of the colors has been preserved — red regions are redder in real life, etc. Click on the image for a higher-resolution version (about 1.6 MB). Even higher resolutions available at HubbleSite.
Not too different, to the naked eye, from previous incarnations of the ultra deep field. That’s okay. I can sit and stare at these images for hours. Every one of those blobs is a galaxy! Holy crap.
I keep meaning to write something substantive about the theft of emails from the Climatic Research Unit (CRU) at the University of East Anglia, but my day job does sometime intervene. (Over six hundred postdoc applications in theoretical physics, but not to worry — only about 400 of them are in areas related to my interests.) There are some good discussions at Time and Foreign Policy, and you can’t poke your nose into the science blogosphere without reading someone’s take on the issue.
My own take is: what in the world is the big deal? Indeed, I would go so far as to ask: what could possibly be the big deal? Most of the noise has simply been nonsensical, focusing on misunderstandings of what scientists mean by the word “trick” and similar deep issues. And some people got upset when a dodgy paper was accepted by a journal, and they discussed giving the journal a cold shoulder. Cry me a river.
But I don’t really want to defend the scientists involved, because I’m not informed enough about who they are and what they did. For all I know, they may be very nasty and unethical human beings. (Actually that’s not true; I know Michael Mann, and he’s one of the nicest guys you’ll ever meet.) And I see no reason not to do a thorough investigation, and hand out appropriate sanctions if there’s real evidence of wrongdoing.
What baffles me is the idea that this changes the conversation about climate change in any way. This isn’t a case like Jan Hendrik Schon, the rogue physicist who rose to prominence on the basis of falsified data, and was later exposed. The job of monitoring the climate is one that has been taken up by more than just one or two groups of people. There have been thousands of peer-reviewed papers that have provided evidence of global warming. Not to mention common sense; when the concentration of CO2 in the atmosphere has shot up dramatically over the last century, and the temperature has done the same thing, it takes some willful stubbornness to avoid the obvious conclusion. All of the noise we’re hearing about “Climategate” is based on politics, not on science.
And that’s what really puzzles me. I understand the non-scientific motivations of certain climate denialists; in the abstract, they don’t want to accept that the unfettered actions of capitalism can ever have any deleterious effects, and in the concrete, many of them are paid by oil companies. (See this charming “letter to the American Physical Society,” whose handful of signatories includes “Roger Cohen, former Manager, Strategic Planning, ExxonMobil.”) Those are powerful incentives to ignore the evidence.
But what is the incentive on the other side supposed to be? What exactly is the motivation for the nefarious conspiracy of people who are supposedly plotting to mislead the world about global warming? What do the people counting oysters get out of this?
Are there a lot of people out there who think that scientists as a group (since the vast majority of scientists appreciate the problems of global warming) have knee-jerk reactions against technology and industry? Let me propose another motivation for whatever corners the East Anglia group might have contemplated cutting: they’ve seen the data, they know what’s happening to the planet, and they’re terrified of what the consequences might be. They know that the other side is motivated by non-scientific concerns, and they want to fight back as hard as they can, both for the good of humanity and for the integrity of science. There’s no question that scientists can go overboard, pulling the occasional shenanigans in the pursuit of their less lofty goals. (Like, you know, other human beings.) But nobody wants to believe that we’re facing a looming global ecological catastrophe. They believe it because that’s what the data imply.
I think we can all agree that I’ve been admirably restrained with respect to talking about my upcoming book before it even appears. (Maybe you don’t think so, but believe me — I’ve been restraining myself.) Die-hards have been able to follow the excitement at the Facebook page, where fascinating details about cover blurbs and review copies have been politely sequestered.
All that is about to end soon! Yesterday I received in the mail an actual copy of the hardcover, a tangible artifact testifying to the reality of this long-anticipated event. Here it is, rubbing shoulders with a few other well-known bestsellers.
The official release date is January 7. Yes, there will be a Kindle edition; at some point later in January there will even be an audio book. And I’m certainly not going to stop you from ordering it. But my publisher tells me that what would be really great is if a bunch of people ordered it exactly on January 7. So that’s when I’ll really be encouraging you.
Even after the book is out, I don’t want to turn the blog into all book, all the time. But I do want to try a book club experiment, where we go through individual chapters, one week at a time, with me revealing some of the thought processes that went into each chapter and all of us having a back-and-forth discussion. Should be fun!
No formal book tour, but I’ll be doing a few readings and events. Check the Facebook page or book web page for more.
To nobody’s surprise, universities are increasingly putting some effort into putting high-quality course lectures on the Web. (Where this ultimately will lead isn’t completely clear.) We’ve already mentioned Leonard Susskind’s lectures on GR at Stanford. Now from Harvard, we have a course on Justice by Michael Sandel. (Via Julian Sanchez.) They really went all-out on the production values, teaming with the local public TV station WGBH; this looks a lot better than what you would get from someone in the middle of the room with a hand-held camera.
The lectures were held in Harvard’s Sanders Theater, which is quite a beautiful space. You get something of an idea what it’s like to be a Harvard undergrad; there are a lot of students in the class. Most professors don’t wear suits and ties, however.