Interna

Lara and Gloria are now 9 months old, and it's time again for our monthly baby update. The girls are now both crawling well. Lara has learned to sit up on her own and Gloria knows how to pull herself up and stand on her feet. She's been doing that since 2 weeks already, but only now has she learned how to get back down in any other way than just letting go and falling backwards on her head. There's no day the babies don't get new scratches or bruises and they are relentlessly curious. The other day they escaped from the baby-safe part of the room and happily chewed on our passports.

When they are not sleeping or crying, they are babbling most of the time. For a few days in a row they pick a favorite syllable that they then repeat endlessly. Presently, Gloria is commenting everything with na-na-na, and Lara is practicing dadn-dadn. I've speculated she's echoing Stefan's "Was mascht Du dadn?" (What are you doing there? Saarland-style). On Monday we took them to the institute and they were duly impressed by the guy next door drawing Feynman-diagrams on the whiteboard, though more interesting still they found all the cables under my desk together with the occasional woodlouse that we evidently host down there.

I always thought babies typically swallow or choke on everything small enough to fit into their mouth. It turns out though the very little ones put things in their mouth but don't swallow. In fact, at this point ours still refuse to eat anything that's not smoothly mashed. They'll just push it around in their mouth for a little and then spit out. (It's called the "gag reflex" and should vanish by 7-9 months. You better not leave your baby alone with the combustion engine anyway.)

Neither Lara nor Gloria have teeth yet. That has not deterred the Swedish health authorities from assigning us dentists' appointment. It's not like they ask you to come, no, they just send a letter with a time, date, and location you have to appear. We actually missed the first two appointments. I then called them and tried to convey the information that the girls don't even have teeth for the dentist to look at, but to no avail. I'm picturing a long corridor with offices where Swedish doctors sit and cross out names of patients that didn't show up for their appointments, or belatedly notice the body part they wanted to examine is missing. But at least we know where our taxes are going. (The same health authorities that require amputees to prove every other year that the missing part hasn't regrown. Still better than no health insurance...)

Stefan was sent a list of gadgets the modern father needs to have, for example the full color, high-def, video monitoring system, that allows you to check on your babies by Skype, or a cry analyzer. But the gadget that I would really like to have is a diaper with an integrated microchip that sends a note to my BlackBerry when the diaper is full, and a number attached to it. It's somewhat degrading to having to push my nose onto baby-butts in order to examine the matter, and Stefan's nose evidently isn't up to the task. The German comedian Michael Mittermeier aptly referred to the nose-on-butt procedure as "the shit-check." Which reminds me, I should really write the report on that paper now...

On the universal length appearing in the theory of elementary particles - in 1938

Special relativity and quantum mechanics are characterized by two universal constants, the speed of light, c, and Planck's constant, ℏ. Yet, from these constants one cannot construct a constant of dimension length (or mass respectively as a length can be converted to a mass by use of ℏ and c). In 1899, Max Planck pointed out that adding Newton's constant G to the universal constants c and ℏ allows one to construct units of mass, length and time. Today these are known as Planck-time, Planck-length and Planck-mass respectively. As we have seen in this earlier post, they mark the scale at which quantum gravitational effects are expected to become important. But back in Planck's days their relevance was in their universality, since they are constructed entirely from fundamental constants.

In the early 20th century, with the advent of quantum field theory, it was widely believed that a fundamental length was necessary to cure troublesome divergences. The most commonly used regularization was a cut-off or some other dimensionful quantity to render integrals finite. It seemed natural to think of this pragmantic cut-off as having fundamental significance, though the problems it caused with Lorentz-invariance. In 1938, Heisenberg wrote "Über die in der Theorie der Elemtarteilchen auftretende universelle Länge" (On the universal length appearing in the theory of elementary particles), in which he argued that this fundamental length, which he denoted r₀, should appear somewhere not too far beyond the classical electron radius (of the order some fm).

This idea seems curious today, and has to be put into perspective. Heisenberg was very worried about the non-renormalizability of Fermi's theory of β-decay. He had previously shown that applying Fermi's theory to the high center of mass energies of some hundred GeV lead to an "explosion," by which he referred to events of very high multiplicity. Heisenberg argued this would explain the observed cosmic ray showers, whose large number of secondary particles we know today are created by cascades (a possibility that was discussed at the time of Heisenberg's writing already, but not agreed upon). We also know today that what Heisenberg actually discovered is that Fermi's theory breaks down at such high energies, and the four-fermion coupling has to be replaced by the exchange of a gauge boson in the electroweak interaction. But in the 1930s neither the strong nor the electroweak force was known. Heisenberg then connected the problem of regularization with the breakdown of the perturbation expansion of Fermi's theory, and argued that the presence of the alleged explosions would prohibit the resolution of finer structures:

"Wenn die Explosionen tatsächlich existieren und die für die Konstante r₀ eigentlich charakeristischen Prozesse darstellen, so vermitteln sie vielleicht ein erstes, noch unklares Verständnis der unanschaulichen Züge, die mit der Konstanten r₀ verbunden sind. Diese sollten sich ja wohl zunächst darin äußern, daß die Messung einer den Wert r₀ unterschreitenden Genauigkeit zu Schwierigkeiten führt... [D]ie Explosionen [würden] dafür sorgen..., daß Ortsmessungen mit einer r₀ unterschreitenden Genauigkeit unmöglich sind."

("If the explosions actually exist and represent the processes characteristic for the constant r₀, then they maybe convey a first, still unclear, understanding of the obscure properties connected with the constant r₀. These should, one may expect, express themselves in difficulties of measurements with a precision better than r₀... The explosions would have the effect... that measurements of positions are not possible to a precision better than r₀.")

In hindsight we know that Heisenberg was, correctly, arguing that the theory of elementary particles known in the 1930s was incomplete. The strong interaction was missing and Fermi's theory indeed non-renormalizable, but not fundamental. Today we also know that the standard model of particle physics is perturbatively renormalizable and know techniques to deal with divergent integrals that do not necessitate cut-offs, such as dimensional regularization. But lacking that knowledge, it is understandable that Heisenberg argued gravity had no role to play for the appearance of a fundamental length:

"Der Umstand, daß [die Plancklänge] wesentlich kleiner ist als r₀, gibt uns das Recht, von den durch die Gravitation bedingen unanschaulichen Zügen der Naturbeschreibung zunächst abzusehen, da sie - wenigstens in der Atomphysik - völlig untergehen in den viel gröberen unanschaulichen Zügen, die von der universellen Konstanten r₀ herrühren. Es dürfte aus diesen Gründen wohl kaum möglich sein, die elektrischen und die Gravitationserscheinungen in die übrige Physik einzuordnen, bevor die mit der Länge r₀ zusammenhängenden Probleme gelöst sind."

("The fact that [the Planck length] is much smaller than r₀ gives us the right to leave aside the obscure properties of the description of nature due to gravity, since they - at least in atomic physics - are totally negligible relative to the much coarser obscure properties that go back to the universal constant r₀. For this reason, it seems hardly possible to integrate electric and gravitational phenomena into the rest of physics until the problems connected to the length r₀ are solved.")

Today, one of the big outstanding questions in theoretical physics is how to resolve the apparent disagreements between the quantum field theories of the standard model and general relativity. It is not that we cannot quantize gravity, but that the attempt to do so leads to a non-renormalizable and thus fundamentally nonsensical theory. The reason is that the coupling constant of gravity, Newton's constant, is dimensionful. This leads to the necessity to introduce an infinite number of counter-terms, eventually rendering the theory incapable of prediction.

But the same is true for Fermi's theory that Heisenberg was so worried about that he argued for a finite resolution where the theory breaks down - and mistakenly so since he was merely pushing an effective theory beyond its limits. So we have to ask then if we are we making the same mistake as Heisenberg, in that we falsely interpret the failure of general relativity to extend beyond the Planck scale as the occurence of a fundamentally finite resolution of structures, rather than just the limit beyond which we have to look for a new theory that will allow us to resolve smaller distances still?

If it was only the extension of classical gravity, laid out in many thought experiments (see eg. Garay 1994), that made us believe the Planck length is of fundamental importance, then the above historical lesson should caution us we might be on the wrong track. Yet, the situation today is different from that which Heisenberg faced. Rather than pushing a quantum theory beyond its limits, we are pushing a classical theory and conclude that its short-distance behavior is troublesome, which we hope to resolve with quantizing the theory. And several attempts at a UV-completion of gravity (string theory, loop quantum gravity, asymptotically safe gravity) suggest that the role of the Planck length as a minimal length carries over into the quantum regime as a dimensionful regulator, though in very different ways. This feeds our hopes that we might be working on unraveling another layer of natures secrets and that this time it might actually be the fundamental one.

---

Aside: This text is part of the introduction to an article I am working on. Is the English translation of the German extracts from Heisenberg's paper understandable? It sounds funny to me, but then Heisenberg's German is also funny for 21st century ears. Feedback would be appreciated!

Theory Carnival: Phenomenological Quantum Gravity

[Geek Mommyprof from Academic Jungle is hosting a carnival on real people's work in theoretical or computational sciences, and what that work entails. She asked me to contribute some lines about what I do for a living, so here we go.]

I am a theoretical physicist and I work on the phenomenology of quantum gravity. Phenomenology is the part of theory that makes contact with experiment. (For more read my earlier post On the Importance of Phenomenology). Quantum gravity is the attempt to resolve our problems in formulating a common treatment for the quantum field theories of the standard model and Einstein's general relativity. Quantum gravity has for a long time been dominated by theory, and it's only been during the last decade or so that more effort has been invested into phenomenology.

I like working in this area because it offers interesting and still unexplored topics, and if there will ever be an experimentally confirmed theory of quantum gravity there's no way around phenomenology. My work requires keeping track of what the theorists are doing and what the experimentalists are planning and trying to find a way to connect both. Since gravity is a very weak interaction, finding evidence for its quantum effects is difficult to do, and so far there has been no signature. In fact, it can be quite frustrating if one puts in the numbers and finds the effect one considered is 40 orders of magnitude too small to be measurable, which is the normal state of affairs. I've joked on occasion I should write a paper "50 ways you can't measure quantum gravitational effects," just so all my estimates will finally be good for something. But there are areas, early universe and high energy densities, high energies and large distances, where it doesn't look completely hopeless.

Lacking a fully established theory of quantum gravity, phenomenology in this area requires developing a model that tests for some specific features, may that be extra dimensions, violations of Lorentz Invariance, antigravitation or faster-than-light travel. Model building is like having a baby. While you work on it, you have an idea of how it will be and what you can do with it. Yet, once it's come into life, it starts crying and kicking and doesn't care at all what you wanted it to do. Mathematical consistency is a very powerful constraint that is difficult to appreciate if one hasn't made the experience: You can't just go and, for example, introduce antigravitating masses into general relativity. It sounds easy enough to just put in stuff that falls up, but once you look into the details the easy ways are just not compatible with the theory, and it turns out to be so easy not. (I should know, since I spent several years on that question and out came a paper that I doubt anybody read.)

You might ask now, well, what has antigravitation got to do with phenomenological quantum gravity? Nothing actually. It's just that people always ask me what I work on and I used to say: A little bit of particle physics and a little bit of cosmology and my recent paper was about this-and-that and I'm also interested in the foundations of quantum mechanics and organizational design, and then I wrote this paper on the utility function in economics and so on. But I figured that what they actually wanted was a three word answer, so that's why I work on phenomenological quantum gravity. On the institute's website it says I work on "high energy and nuclear physics," which isn't too far off, still, 5 is larger than 3.

But no matter what the headline, what my work looks like is like this: I start with an idea and try to build a model that incorporates it while maintaining mathematical consistency, after all that's what I sat through all these classes for. In addition, the model should be compatible with available data and ideally predict something new. The failure rate is high. But there's the occasional idea that turns out not to be a failure. It gets written up and submitted to a journal and, if all goes well, gets published. I usually publish in Classical and Quantum Gravity, Physics Letters B or Physical Review D.

In the process of working on a paper, I almost always have an ongoing exchange with some people who work on related topics. If the finances allow it, I might visit them or invite them to come here. I might also attend a workshop or conference, or organize one myself. In addition, my work brings the usual overhead like writing or reviewing grant proposals, attending or giving seminars, coming up with a thesis topic, reading applications, reviewing papers, attending faculty meetings and so on. I presently work at a pure research institute, the Nordic Institute for Theoretical Physics in Stockholm, and have no teaching duties, which has advantages and disadvantages. And if you are following this blog you know that I'm only just back from parental leave.

For more on what my work is like, see also What I am is what I am and One day. You can also follow me on Twitter, or Google+.

Interna

We'll resettle to Stockholm in the coming week and fight some bureaucratic fights, so you might not hear much from us for a while.

Since blogpoll apps have a tendency to vanish, here's a summary of the two recent polls.

Do you die when you go through a transmitter?

• Yes, you die. 36.8% (70)
• No, you don't die. 33.7% (64)
• Some part of the process is physically impossible. 25.3% (48)
• Something else (please explain in comments). 4.2% (8)

Do you believe in free will?

• I believe human decisions are in principle predictable and there is no free will. 35.4% (45)
• I believe human decisions are in principle predictable, but still there can be free will. 28.3% (36)
• I believe human decisions are not predictable, neither in practice nor in principle, and we have free will. 27.6% (35)
• I believe something else that I'll explain in the comments. 8.7% (11)

And yet it moves

This September, it's been 16 years since I started studying physics. That's 2^2^2 years which have gone by and bye. Stefan started in 1987. The first physics headline I can recall consciously taking note of was the 1995 discovery of the top quark, and Stefan cites inspiration by the Supernovae 1987a. This got us into a conversation about the most striking insights physics has delivered since we went to university. Here are our winners:

The biggest surprise for everybody except Raffael Sorkin was that the Cosmological constant is not zero. Since 1998, evidence has been adding up and up that our universe undergoes accellerated expansion caused by a small, positive cosmological constant. For more, read my earlier post on the Cosmological Constant and its cousins.

When I was a graduate student, physicists were still debating whether black holes exist or if black holes are just a mathematically possible solution to Einstein's field equations that is however not realized in nature. The first evidence was available already back then, but it took a while for more observations to be made and gradually everybody came to accept that black holes exist for real. (Well, almost everybody.) For more on black holes, see here.

Suspected by many, it still took several decades to unambiguously show that neutrinos have mass. Due to the neutrinos' weak interaction, many years of data had to be collected over different propagation distances at different energies. It wasn't until 2001 that the option of decay rather than oscillation could be ruled out by the SNO results. Yet, the neutrino sector of the standard model still has some mysteries to offer.

In my quantum mechanics class, EPR-type tests of Bell's theorem were Gedankenexperimente. Now they are reality. So are other tests of the foundations of quantum mechanics, down to single photons, double-slit experiments with atoms, while our understanding of entanglement and decoherence has increased and superpositions of larger and larger molecules succeed.

And on the computational side, amazing simulations of large scale structure formation have become possible. If you haven't seen the Millenium Simulation, it's time well spent.

The recent issue of Physik Journal (the membership journal of the German Physical Society) has an article "Physik im Aufwind" that summarizes recent statistical trends in physics. The below shows the number of beginning students in physics by year. I started in the middle dip. It is good to see that physics is drawing in more young people again.

The Third Hand

Last week at the airport I read the July/August issue of Scientific American Mind, which has an interesting article "Reflections on the Mind" by two Ramachandrans from the Center for Brain and Cognition at UCSD. It is a brief walk through some recent experiments testing how our brain constructs and interprets our own body and how that interpretation can be twisted.

One experiment you have probably heard of is that letting amputees "see" a lost arm or leg with a mirror that doubles the remaining one allows them to scratch or move it. That is, scratching the reflection they see in place of the lost body part does register in the brain, even though there is no direct sensory input. Some months back, we also learned about the "body swap" illusion that makes use of somewhat more sophisticated technology to create the illusion that one is moving a different body, with the aim to test how readily the brain accepts it as one's own. The SciAm Mind article suggests some low tech experiments you can try at home. For example, using a mirror to produce an image of your hand in place of the actual hand and then stroking the image produces a conflict in the brain because the visual input doesn't match the expectation. As a result your hidden arm might feel numb, though there's nothing wrong with it.

This reminded me of a trick we used to play on the mind as children: Lock hands with a friend, with the index fingers straight (see image below). With the free hand, rub up and down your and your friend's index fingers (2nd image). We used to call it "rubber finger." Everybody I know who tried found it to feel weird. I don't know why, but it seems that the brain expects some signal from the friend's finger. It doesn't make a lot of sense to me since you'd need three hands for that. If you have a good interpretation, let me know.

Predetermined Lunch and Moral Responsibility

The final session of the 2011 FQXi conference concluded with a brief survey. The question “Is a ‘perfect predictor’ of your choices possible?” was answered with “Yes” by 17 out of 40 respondents. The follow-up question “If there were, would it undermine human free will?” was answered with “Yes” by 18 out of 38 respondents.

I’m in the Yes-Yes camp, and I was surprised that doubting one’s own free will was so common among the conference participants. It is striking how unrepresentative this result is for the general population who likes to hold on to the belief that personal choices are undetermined and unpredictable. In a cross-cultural study with participants from the United States, Hong Kong, India and Colombia, Sarkassian et al found that more than two thirds of respondents (82% USA, 85% India, 65% Hong Cong, 77% Colombia) believe that our universe is indeterministic and human decisions are “not completely caused by the past”(exact wording used in the study).

One of the likely reasons many people believe in free will is that if fundamentally there is no such thing as free will, how come that most of us* have the feeling that we do make decisions?

Lacking a good theory of consciousness, it may be that rather than making decisions, the role of our consciousness is to simply provide aggregated information about what our brain and body was doing, is currently doing, and provide a crude extrapolation of this information into the future. As we grow up, we become better at predicting what will be happening next –in our surrounding as well as with our own body and mind – and may mistake our prediction of what we will be doing for an intent to do it, and our imperfection of making precise predictions creates the illusion that we had a choice. (I doubt I'm the first to have this thought. If you know a reference with similar spirit, please let me know.)

This would mean, if you slap your forehead now, rather than consciously deciding to do so and making the choice to perform this action (which we may call the “standard interpretation”) your neuronal network has arrived at the necessary state that immediately precedes this action and your consciousness notes that next thing that will likely happen is you’ll be slapping your forehead, which it interprets as your impulse to do so (we may call it the “self-extrapolation interpretation”). You are not entirely certain about this since you have learned that your subconscious on occasion makes twists that your consciousness fails to properly predict, thus the possibility remains you’ll not be slapping your forehead after all.

It has in fact been argued that the reason why most people reject determinism it is their inability to predict actions, first by Thomas Reid I am told, and later by Spinoza, not that I actually read either. So possibly theoretical physicists are more inclined to believe in determinism because making precise predictions is their day job ;-)

Sean Carroll recently argued that free will can have a peaceful coexistence with modern science on an emergent level, in an effective description of human beings. That only works though if in the process of arriving at that effective level you throw away information that was fundamentally there. I believe Sean is aware of that when he writes “But we don’t know [all the necessary information to predict human decisions], and we never will, and therefore who cares?”

Well, I'd say that if you make room for free will by neglecting in principle available information, then his notion of free will is an empty concept that, as I've learned from the comments to his blogpost, the philosopher Edward Fredkin more aptly named “pseudo free will.”

I'm only picking around on Sean's post because it's short enough for you to go and read it unlike hundreds of pages that some philosophers have spent to say essentially the same thing. In any case, it is interesting how some scientists desperately try to hold on to some notion of free will in the face of an uncaring universe. I believe one of the reasons is that rejecting free will sheds a light of doubt on ones' moral responsibility, and since I feel personally offended, some words on that.

Morals and Responsibility

Whether the universe evolves deterministically, or whether its time evolution has a random element, an individual, fundamentally, has no choice over his or her actions in either case. It is then difficult to hold somebody responsible for actions if they had no way to make a different choice. This and similar thoughts have spurred a number of studies that claim to have shown that priming people’s belief in a deterministic universe reduces their moral responsibility.

For example, a study by psychologists Kathleen Vohs and Jonathan Schooler (summary here) had half of the participants read a text passage arguing against the existence of free will. All participants then filled out a survey on their belief in free will and completed an arithmetic test in which they had an option to cheat, but were asked not to. It turned out that disbelief in free will was correlated with the amount of cheating. Also, in the previously mentioned study by Sarkassian et al, most participants held the opinion that in a deterministic universe people are not responsible for their actions.

However, the issue of moral responsibility is a red herring, for morals are human constructs whether or not we have free will . From the viewpoint of natural selection, the reason why most of us don’t go around cheating, stealing, or generally making others suffer is not that it’s illegal or immoral or both, but that our self-extrapolation correctly predicts we will be suffering in return. Not primarily because we may be thrown into jail but because our brains would keep returning to that moment of offense, imagining how other people suffered because of our wrongdoing, telling us that way that we did act against the interests of our species, and more generally reducing our overall fitness.

In fact, that our species still exists and seems to be doing reasonably well means that most of us do not take pleasure in letting others suffer. The reason we don’t perform “immoral” acts is that we can’t: We’re the product of a billion years of natural selection that has done well to sort out those who pose a risk to our future, and we've called the result “moral.” (I am far from saying one can derive morals.)

The less consequences an act has for ones’ own future and that of others the larger the variety in people’s behavior. (There are more people jaywalking than strangling talk show hosts in front of running cameras.) That we have laws enforcing rules is because there remain people among us whose brains are some sigma away from the average and our laws are one more channel of natural selection, keeping these people off the streets, trying to readjust their brain’s functionality, or at least generally making their lives difficult. David Eagleman recently made a very enlightened argument for a rethinking of our justice system in light of neurobiological evidence for our reduced capability to change our brain’s working.

In a world without free will, we should not ask if a person is worth blaming, but simply look for the dominant cause of the problem and take steps to solve it.

Similarly, instead of asking if who is morally responsible we should ask what incentives do people have. The problem with the above mentioned test for moral responsibility in a deterministic universe it that the consequences of the alleged “immoral” act of cheating are entirely negligible. Putting forward the plausible thesis that the illusion of free will is beneficial to our brain’s performance (or otherwise, why is it so universal?), the test subject’s cheating might have been simply a reassurance of their illusion. If one would replace the temptation to cheat on a test with a questionnaire for the participant’s likings in food and then offer snacks, chances are those who were suggested a deterministic universe would feel the urge to select a food they do not usually prefer. Better still, one may have told the test subjects that the better their brains in the deterministic universe are adapted to living a modern life in modern times, the less likely they will be to perform “immoral acts” that violate the (written or unwritten) rules and values of that society (whether that is true or not doesn't matter).

Predetermined Lunch: Not Free Either

That our decisions are determined does not mean that we do not have to make them, which is a common misunderstanding, nicely summarized by Sean Carroll’s anecdote

“John Searle has joked that people who deny free will, when ordering at a restaurant, should say ‘just bring me whatever the laws of nature have determined I will get.’”

The decision what you will eat may be predetermined, but your brain still has to crunch the numbers and spit out a result. One could equally well joke that your computer, rather than running the code you’ve written, returns it back to you with the remark that the result is predetermined and follows from your input. Which is arguably true, but still somebody or something has to actually perform the calculation. Though in a deterministic universe it is in principle possible, it is highly questionable that the cook will be able to make the prediction about your order in your place, even after asking Laplace’s demon for input.

In other words, even if you don't have a free will, to make a decision you still have to collect all the information you deem necessary and scan your memory and experience to build an opinion, or perform whatever other process you have come to think is a good way to make decisions, may that be rolling a dice or calling your mom. Whether or not you believe you have a freedom in making a decision doesn’t save you the energy needed to do it.

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The original version of this post had a poll included on the question "Do you believe in free will?" but the applet is no longer functional. The results were

• I believe human decisions are in principle predictable and there is no free will. 35.4% (45)
• I believe human decisions are in principle predictable, but still there can be free will. 28.3% (36)
• I believe human decisions are not predictable, neither in practice nor in principle, and we have free will. 27.6% (35)
• I believe something else that I'll explain in the comments. 8.7% (11)

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* The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, describes Depersonalization Disorder as follows: “The essential features of Depersonalization Disorder are persistent or recurrent episodes of depersonalization characterized by a feeling of detachment or estrangement from one's self. The individual may feel like an automaton or as if he or she is living in a dream or a movie. There may be a sensation of being an outside observer of one's mental processes, one's body, or parts of one's body.”

Thus, interestingly enough, not all of us share the feeling of being in charge of one's actions. That the failure to relate to oneself is filed under "disorder" seems to me to show that believing in free will is beneficial to the individual's functionality and well-being.

From my notepad

The 2011 FQXi conference was an interesting mix of people. The contributions from the life sciences admittedly caught my attention much more than those of the physicists. Thing is, I’ve heard Julian Barbour’s and Fotini Markopoulou’s talk before, I’ve seen Anthony Aguirre’s piano reassemble from dust before, and while I hadn’t heard Max Tegmark’s and George Ellis’ talk before I’ve read the respective papers. The discussions on physics conferences also seem to have a fairly short recursion time and it’s always the same arguments bouncing back and forth. One thing I learned from David Eagleman’s talk is that neuronal response decreases upon repetitive stimuli – so now I have a good excuse for my limited attention span in recursive discussions ;-)

All the talks on the conference were recorded and they should be on YouTube sooner or later. Stefan also just told me that the talks from the 2009 FQXi conference are on YouTube now. (My talk is here. Beware, despite the title, I didn’t actually speak on Pheno QG. Also, I can’t for the hell of it recall what that thing is I’m wearing.) Anyways, here is what I found on my notepad upon return, so you can decide what recording you might want to watch:

• Mike Russell gave a very interesting talk on the origin of life or at least its molecular ancestors. He explained the conditions on our home planet 2 billion years ago and the chemical reactions he believes must have taken place back then. He claims that under these circumstances, it was almost certain that life would originate. With that he means a molecule very similar to ADP, the most important cellular energy source, is very easy to form under certain conditions that he claims were present in the environment. From there on, he says, it’s only a small step to protein synthesis, RNA and DNA and they are trying to “re-create” life in the lab.
  
  Chemical reactions flew by a little too fast on Russell’s slides, and it’s totally not my field, so I have no clue if what Russell says is plausible. Especially I don’t know how sure we really can be the environment was as he envisions. In any case, I took away the message that the molecular origins of life might not be difficult to create in the right environment. Somewhat disturbingly, in the question session he said he has trouble getting his work funded.


• Kathleen McDermott, a psychologist from Washington University, reports the results of several studies in which they were trying to find out which brain regions are involved in recalling memory and imagining the future. Interestingly enough, in all brain regions they looked at, they found no difference in activity in between people recalling an event in the past and envisioning one in the future.


• David Eagleman gave a very engaging talk about how our brains slice time and process information without confusing causality. The difficulty is that the time which different sensory inputs needs to reach your brain differs by the type and location of input, and also the time needed for processing that might differ from one part of the brain to the next. I learned for example that the processing of auditory information is faster than that of visual information. So what your brain does to sort out the mess is that it waits till all information has arrived, then presents you with the result and calls it “right now,” just that at this point it might be something like 100ms in the past actually.
  
  Even more interesting is that your brain, well trained by evolution, goes to lengths to correct for mismatches. Eagleman told us for example that in the early days of TV broadcast, producers were worried that they wouldn’t be able to send audio and video sufficiently synchronized. Yet it turned out, that up to 20ms or so your brain erases a mismatch between audio and video. If it gets larger, all of a sudden you’ll notice it.
  
  Eagleman told us about several experiments they’ve made, but this one I found the most interesting: They let people push a button that would turn on a light. Then they delayed the light signal by some small amount of time 50ms or so past pushing the button (I might recall the numbers wrong, but the order of magnitude should be okay). People don’t notice any delay because, so the explanation, the brain levels it out. Now they insert one signal that comes without delay. What happens? People think the light went on before they even pushed the button and, since the causality doesn’t make sense, claim it wasn’t them! (Can you write an app for that?) Eagleman says that the brains ability to maintain temporal order, or failure to do so, might be a possible root of schizophrenia (roughly: you talk to yourself but get the time order wrong, so you believe somebody else is talking) and they’re doing some studies on that.


• From Simon Saunders talk I took away the following quotation from a poem by Henry Austin Dobson on “The Paradox of Time:”
  
  
  “Time goes, you say? Ah no!
  Alas, Time stays, we go;
  Or else, were this not so,
  What need to chain the hours,
  For Youth were always ours?
  Time goes, you say?- ah no”



• Malcom MacIver, who blogs at Discover, studies electric fish. If that makes you yawn, you should listen to his talk, because it is quite amazing how the electric fish have optimized their energy needs. MacIver also puts forward the thesis that the development of consciousness is tied to life getting out of water simply because in air one can see farther and thus arises the need for ahead planning. In a courageous extrapolation of that, he claims that our problem as a species on this planet is that we can’t “see” the problems in other parts of the world (e.g. starving children) and thus fail to properly react to them. I think that’s an oversimplification and I’m not even sure that is the main part of the problem, but it’s certainly an interesting thesis to think about. He has a 3 part series on posts about this here: Part I, Part II, Part III.


• Henry Roediger from the Memory Lab at Washington University explained us, disturbingly enough, that there is in general no correlation between the accuracy of a memory and the confidence in it. For example, shown a list of 16 words with a similar theme (bed, tired, alarm clock, etc) 60% of people (or so, again: I might mess up the numbers) will “recall” the word “sleep” with high confidence though it was not on the list. A true scientist, he is trying to figure out under which circumstances there is a good correlation and what this means for the legal process.


• Alex Holcombe told us about his project evidencechart.com, a tool to collect and rate pro and con arguments on a hypothesis. I think this can be very useful, though more so in fields where there actually is some evidence to rate on.

Scott Aaronson's talk on free will deserves a special mentioning, but I found it impossible to summarize. I recommend you just watch the video when it comes out.

Interna

I am back in Germany and happily reunited with the family. Time might not exist and its passage be an illusion, but the babies are growing irrespective, and our arrow of time points towards baby gates. Lara and Gloria are now 8 months old. They spent the previous week, that I was away for the FQXi conference, with Stefan at their grandma's place. It is difficult to say if they missed me during my absence or if they recognize me upon coming back. They do however clearly recognize our apartment and their own beds. Lara for example had found a way to lie in the corner of her bed in exactly the right angle that she could just look out through the door and onto the corridor - a position she immediately resumed.

The girls are now both moving around by doing the army crawl and Gloria has made first attempts to crawl on her knees. At present, she seems to be aiming at a career as breakdancer, standing on hands and the toes of one foot, turning around chasing the other foot, sometimes slipping and bumping on her head. Interestingly enough, Gloria has completely skipped the phase of moving around by rolling sidewards that Lara has had. Gloria meanwhile has learned how to clap her hands, which she does with enthusiasm. They can now both grab a pacifier and put them into their own mouth and if Lara is in a good mood, she'll try to put it into your mouth.

The babies are both fascinated by all things shiny and tiny and stringy and I've had the somewhat belated insight that the purpose of baby toys is not to entertain the baby but to distract the baby from mommy's toys till it's old enough to realize that pulling on a cable isn't always a good idea.

Our rapid throughput of clothes has been slowing down and we've childproofed the apartment as far as possible. However, in 2 weeks we're packing bags and going back to Stockholm where I will be working while Stefan is on parental leave. So, we'll have to childproof a second apartment and that with the difficulty that we can't remove items or drill into walls because the items aren't ours and the walls are solid concrete.

But, hey, we'll manage somehow. Baby reading this month is an article on "Baby Power" in SciAm Mind according to which mommy brains sprout new neurons, and body chemistry changes towards higher risk taking and better memory performance, at least when it comes to tracking down food. If you are a rat that is. The same article also informs us "that (human) mothers are more likely to rate their infant's odors as pleasant, compared with nonmothers" (Look, an English compound noun! And it's not my making!). Maybe I'm an aberration but, prolactin or not, shit still smells like shit to me. Spiegel Online informs us that we're supposed to train baby's concentration skills by the age of one (at the latest), but then Parents don't matter that much at least when it comes to the child's education and income, and the Globe and Mail reports that striving to be supermom is correlated with depression. So maybe we'll wait with teaching the babies differential geometry on complex spaces for some more while.

Will AI cause the extinction of humans?

Yesterday, at the 2011 FQXi conference in Copenhagen, Jaan Tallinn told us he is concerned. And he is not a man of petty worries. Some of us may be concerned they’ll be late for lunch or make a fool of themselves with that blogpost. Tallinn is concerned that once we have created an artificial intelligence (AI) superior to humans, the AIs will wipe us out. He said he has no doubt we will create an AI in the near future and he wishes that more people would think about the risk of dealing with a vastly more intelligent species.

Tallinn looks like a nice guy and he dresses very well and I wish I had something intelligent to tell him. But actually it’s not a topic I know very much about. Then I thought, what better place to talk about a topic I know nothing about than my blog!

Let me first say I think the road to AI will be much longer than Tallinn believes. It’s not the artificial creation of something brain-like with as many synapses and neurons that’s the difficult part. The difficult part is creating something that runs as stable as the human body for a sufficiently long time to learn how the world works. In the end I believe we’ll go the way of enhancing human intelligence rather than creating new ones from scratch.

In any case, if you would indeed create an AI, you might think of making humans indispensible for their existence, maybe like bacteria are for humans. If they’re intelligent enough, they’ll sooner or later find a way to get rid of us, but at least it’ll buy you time. You might achieve that for example by never building any AI with their own sensory and motor equipment, but make them dependent on the human body for that. You could do that by implanting your AI into the, still functional, body of braindead people. That would get you in a situation though where the AIs would regard humans, though indispensable, as something to grow and harvest for their own needs. Ie, once you’re adult and have reproduced, they’ll take out your brain and move in. Well, it kind of does solve the problem in the sense that it avoids the extinction of the human species, but I’m not sure that’s a rosy future for humanity either.

I don’t think that an intelligent species will be inherently evil and just remove us from the planet. Look, even we try to avoid the extinction of species on the planet. Yes, we do grow and eat other animals but that I think is a temporary phase. It is arguably not a very efficient use of resources and I think meat will be replaced sooner or later with something factory-made. You don’t need to be very intelligent to understand that life is precious. You don’t destroy it without a reason because it takes time and resources to create. The way you destroy it is with negligence or call it stupidity. So if you want to survive your AI you better make them really intelligent.

Ok, I’m not taking this very seriously. Thing is, I don’t really understand why I should be bothered about the extinction of humans if there’s some more intelligent species taking over. Clearly, I don’t want anybody to suffer in the transition and I do hope the AI will preserve elements of human culture. But that I believe is what an intelligent species would do anyway. If you don’t like the steepness of the transition and want more continuous predecessors of humans, then you might want to go the way I’ve mentioned above, the way of enhancing the human body rather than starting from scratch. Sooner or later genetic modifications of humans will take place anyway, legal or not.

In the end, it comes down to the question what you mean by “artificial.” You could argue that since humans are part of nature, nothing human made is more “artificial” than, say, a honeycomb. So I would suggest then instead of creating an artificial intelligence, let’s go for natural intelligence.

FQXi Conference 2011

We just arrived in Copenhagen after a 2-day trip on the National Geographic Explorer, a medium sized cruise ship, along Norway’s coast. On board were about 130 scientists and a couple of spouses in different sizes, plus an incredibly efficient, friendly, and competent crew that didn’t mind having nosy physicists hanging around on the bridge.

The 2011 FQXi conference turns out to be very different from the previous one (2009 on the Azores), and that not only thanks to the unique bonding experience of shared sea-sickness. As Sean Carroll mentioned the other day, during the organization of this conference on the nature of time, the FQXi folks were confronted with an application for a similar event with a similar topic and so they decided to join forces. As a result, this conference is larger and much more interdisciplinary than the previous one. Besides the physicists and philosophers, there are neurobiologists, biologists and psychologists, and a selection of guys interested in artificial intelligence from one or the other perspective, as well as a crew with cameras that are here for PBS I am told.

Among the physicists, the usual suspects are Max Tegmark and Anthony Aguirre, Paul Davies, George Ellis, David Albert, Garrett Lisi, Fotini Markopoulou, Julian Barbour, and Scott Aaronson. But there’s also Geoffrey West from the Santa Fe Institute, Jaan Tallinn, one of the developers of Skype, and David Eagleman the possibilian, just to mention a few. Also around are George Musser from Scientific American and Zeeya Merali who is blogging for FQXi here. There’s a list of alleged attendees here, though some of them I haven’t seen so far.

It is an interesting mix of people. I do enjoy interdisciplinary events a lot because there is always some cool research to learn about that I didn’t know of before. I have however grown skeptic about the benefits of interdisciplinarity when it comes to pushing forward on a particular problem. Take a topic such as free will or the origin of our impression of “now” that might or might not be an illusion. Yes, neurobiologists and psychologists have something to say about that. But they don’t in fact mean the same as physicists and I am not sure that, for example, the question how we achieve to remember the past and imagine the future, or fail to distinguish between true and false memory has any relevance for physicists trying to figure out the relevance of the past hypothesis, the consistency of alternatives to the block universe, or the role of observers in the multiverse. In fact, you already have people talking past each other within one discipline: If you ask three physicists what they mean with “free will” you’ll get four different answers. And after you’ve spent a significant amount of time figuring out what they mean to begin with there isn’t much left they have to say to each other.

That’s the downside of mixing academics – in my experience it does not add depth. Interdisciplinary exchange however adds breadth. Talking to somebody who has addressed a question for a completely different reason and with completely different methods helps one look at it from a different point of view, opening new ways forward. In my opinion though the largest benefit of events like this conference comes from just getting together a group of interesting and intelligent people who make an effort to listen to and complement each other. After some years at PI and NORDITA I’ve pretty much come to take for granted having plenty of folks at my disposal to talk to should I feel like it, but after the baby break I appreciate the opportunity for such exchange much more.

The idea with putting us on a ship was clearly to get us off the Internet for some while. I personally don’t have the impression people on the conferences I usually go make obsessive use of the internet, but evidently some need to have an evil third party as an excuse for not being available at least for a few days. I don’t find it such a great idea to punish all of us because a few guys can’t live without their newsfeed. I wasn’t the only one with family at home who would have appreciated at least a phone. (For an appropriate price that is. If you really, really had to you could have paid for an internet connection at $10 per kB or something like that.)

These are some first impressions. If I've had some time to process what I've heard and learned I might summarize some of the main questions that were discussed. But now (whatever that might be) I have to locate my baggage which I've last seen this morning vanishing into a bus somewhere.

Away note

I'll be away for a week on the FQXi conference "Setting Time Aright." A significant amount of the participants are reportedly nuts, so I will be in good company. I'm supposed to moderate a session on "Choice" for reasons that are somewhat mysterious to me, but since I don't believe in free will I guess they had no choice, haha.

This is my first conference attendance since the babies and, believe me, it's required a significant amount of organization. It didn't help they're doing half of it on a ship and the idea of having to get around on a ship with a twin stroller didn't really appeal to Stefan and me. So I go, and Superdaddy stays with the babies while I'll cry over the no-signal sign on my BlackBerry. Side effects may include blogging congestion.

Physics and Philosophie

I'm looking for topics where theoretical physics has a relevance for philosophy, for no particular reason other than my curiosity and maybe yours as well. Here's the usual suspects that came to my mind:

1. Are there limits to what we can possibly know? The human brain has a finite capacity and computing power. What limits does this set? Is it possible to extend? What is consciousness?


2. Why is the past different from the future? What is "The Now" and why do we have an "arrow of time"? (Or several?)


3. Is there a fundamental theory that explains everything we observe and experience? Is this theory unique and does it explain everything only in principle or also in practice?


4. Do we have free will? And what does that question mean?


5. Are there cases where reductionism does not work? And what does that imply for 3?


6. What is the role of chaos and uncertainty in the evolution of culture and civilization? Is it possible to reliably model and predict the dynamics of social systems? If so, what does that mean for 4?


7. What is reality? What does it mean to "exist" and can an entirely mathematical theory explain this? Does everything mathematical exist in the same way? Why does anything exist at all?


8. And Stefan submits: What is the ontological status of AdS/CFT?

What makes you you?

Stefan's life is tough. When he comes home, instead of a cold beer (I support the local wineries) and dinner (ha-ha-ha) he gets one of the crying babies and a washcloth. And then there's his wife who lacks googletime and greets him with bizarre questions. What frequency does a CD player operate on? Something in the near infrared. How many atoms do you need to encode one bit? Maybe somewhat below the million it was in 2008. And why does he actually know all this stuff? Male brains are funny. He does not, for example, know that the Aspirin is in the medicine cabinet, out of all places. But yesterday he gave it a pass, so here's my question to you.

Suppose you have a transmitter, spaceship enterprise style. It reads all the information of all particles in your body (all necessary initial values), disintegrates your body, sends the information elsewhere, and reassembles it. Did you die in that process?



You could object that this process isn't physically possible, either theoretically or practically. Theoretically, there are for example the no-cloning and no-teleportation theorems in quantum information. But you might not actually need all the quantum details to reconstruct a human body. (I'm not sure though the role of quantum physics for consciousness has yet been entirely clarified.) And, if I reassemble you elsewhere you are arguably different in that the relative location of your body to all other objects in the universe has changed. But again, it doesn't seem like that's of any relevance. Or you could say that there won't be enough time to perform this process ever in the history in the universe or something like that. But these answers seem unsatisfactory to me.

Then you might say, well, if it looks like me, walks like me, and quacks like me, it probably is me. That is, nobody, including the person you have assembled could tell any difference. So that would seem like you didn't die.

On the other hand, the operation of your brain has a discontinuity in its timeline in the sense that it didn't do anything during transmission. That is in contrast to, say, anesthesia where your brain is actually quite active. (Interesting SciAm article on that here.) So that would seem like that what constitutes 'you' did cease to operate and 'you' did die.

But then again, who really cares if you stopped thinking for some seconds and then continued that process while in between you changed the set of quarks and electrons you're operating with. However, then consider now I don't send the information to one place, but to ten. And I assemble not one you, but ten. Which one are you?

Oh-uh, headache. I can understand Stefan does prefer to bath the baby. Now where is the Aspirin?

Was there really a man on the moon? Are you sure?

Some weeks ago, the tree octopus made headlines again. If you had never heard of this creature before, don’t worry, it is an internet hoax used for classes on information literacy. It is easy enough to laugh about the naiveté of students believing in the tree octopus. Or people believing in spaghetti trees for that matter. Scientists in particular are obliged to carefully check all facts they use in their arguments. But in reality, none of us can check all the facts all the time. A lot of what we know is based on trust and an ethereal skill called ‘common sense.’ We’re born trusting adults tell us the truth – about the binky fairy. Most of us grow up adding a healthy dose of skepticism to any new information, but we still rely heavily on trusted sources and the belief that few people are willfully evil. What happened to that in the age of the internet?

When I write a paper, I usually make an effort to check that the references I am citing do actually show what they claim, at least to some level. Sometimes, digging out the roots of a citation tree holds spaghetti surprises. But especially when it comes to experiments, fact checking comes to a quick halt because it would simply take too much time putting under scrutiny each and everything. And then peer review has its shortcomings. In my daily news reading however I am far less careful. After all, I’m not being paid for it and I have better things to do than figuring out if every story I read (Can you really get stuck on an airplane’s vacuum toilet?) is true. Most of the time it doesn’t actually matter because, you see, urban legends are entertaining even if not true. And, well, don’t flush while you s it.

I think of myself as a very average person, so I guess that most of you use similar recipes as I to roughly estimate a trust-value of some online recource. The rule of thumb that I use is based on two simple questions: 1) How much effort would one have to make to fake this piece of information in the present form, and 2) How evil would one have to be.

How much effort would one have to make to put up a website about a non-existing animal? Well, you have to invest the time to write the text, get a domain, and upload it. I.e. not so very much. How evil do you have to be? For the purpose of teaching internet literacy, somebody probably believed he was being good. Trust-value of the tree-octopus: Nil. How much effort do you have to make to fake some governmental website? Some. And it’s probably illegal too, so does require some evil. How much effort would you have to make to fake the moon landing?

Of course such truth-value estimates have large error-bars. Faking somebody else’s writing style for example can be quite difficult (if it wasn’t I’d be writing like Jonathan Franzen), but depends on that writing style to begin with. If you’ve never registered a domain before you might vastly overestimate the effort it takes. And how difficult is it really to convince some billion people the Earth is round? (Well, almost.) Or to convince them some omniscient being is watching over them and taking note every time they think about somebody else’s underwear? There you go. (And Bielefeld, btw, doesn’t exist either.)

The trustworthiness of Wikipedia is a question with more than academic value. For better or worse, Wikipedia has become a daily source of reference for hundreds of millions of people. Its credibility comes from its articles being scrutinized by millions of eyes. Yet, it is very difficult to know how many and which people did indeed check some piece of information, and how much they were influenced by the already existent entry. The English Wikipedia site thus, very reasonably, has a policy that information needs to have a source. Reasonable as that may sound, it has its shortcoming, a point that was made very well in a recent NYT article by Noam Cohen who reports on a criticism by Achal Prabhala, an Indian advisor to the Wikimedia foundation.

There is arguably information about the real world that is not (yet?) to be found in any published sources. Think of something trivial like good places in your neighborhood to find blackberries (the fruit)¹. More interesting, Prabhala offered the example of a children’s game played in some parts of India, and its Wikipedia article in the local language, Malayalam. Though the game is known by about 40 millions of people, there is no peer reviewed publication on it. So what would have constituted a valid reference for the English version of the website? What counts as a trusted source? Do videos count? Do the authors of the Wikipedia article have to random sample and analyze sources with the same care as a scientific publication would require? It seems then, the information age necessitates some rethinking of what constitutes a trusted source other than published works. Prabhala says:

“If we don’t have a more generous and expansive citation policy, the current one will prove to be a massive roadblock that you literally can’t get past. There is a very finite amount of citable material, which means a very finite number of articles, and there will be no more.”

Stefan remarked dryly they could just add a reference to Ind. J. Anth. Cult. [in Malayalam], and nobody would raise an eyebrow. Among physicists this is, tongue-in-cheek, known as “proof by reference to inaccessible literature” (typically to some obscure Russian journal in the early 1950s). The point is, asking for references is useless if nobody checks even the existence of these references. Most journals do now have software that checks reference lists for accuracy and at the same time for existence. The same software will inevitably spit out a warning if you’re trying to reference a living review.

But to come back to Wikipedia: It strikes me as a philosophical conundrum, a reference work that insists on external references. Not only because some of these references may just not exist, but because with a continuously updated work, one can create circular references. Take as an example the paper “Moisture induced electron traps and hysteresis in pentacene-based organic thin-film transistors” by Gong Gu and Michael G. Kane, Appl. Phys. Lett. 92, 053305 (2008). (Sounds seriously scientific, doesn’t it?) Reference [13] cites Wikipedia as a source on fluorescent lamps. There is a paper published in J. Phys. B that cites Wikipedia as a source for the double-slit experiment, and a PRL that cites the Wikipedia entry on the rainbow. Taemin Kim Park found a total of 139 citations to Wikipedia in the fields of Physics and Astronomy in the Scopus database as of January 2011².

That citation of Wikipedia itself would not be a problem. But the vast majority of people who cite websites do not add the date on which they retrieved the site. More disturbingly, the book “World Wide Mind” that I read recently, had a few “references” to essays by mentioning they can easily be found searching for [keywords], totally oblivious to the fact that the results of this search changes by the day, depends on the person searching, and that websites move or vanish. (Proof by Google?)

While the risk for citation loops increases with frequently updated sources, it is not an entirely new phenomenon. A long practiced variant of the “proof by reference” is citing one’s own “forthcoming paper” (quite common if page restrictions don’t allow further elaboration), but in this forthcoming paper - if it comes forth - one references the earlier paper. After ten or so self-referencing papers one claims the problem solved and anybody who searches for the answer will give up in frustration. (See also: Proof by mutual reference.)

Maybe the Wikipedia entry on the octopus hoax is a hoax?

Take away message: References in the age of the internet are moving targets and tracing back citations can be tricky. Restricting oneselves to published works only leaves out a lot of information. Citation loops by referencing frequently updated websites can create alternate realities. But don’t worry, somewhere in the level 5 multiverse it’s as real as, say, the moon landing.

Have you cited or would you cite a Wikipedia article in a scientific publication? If you did, did you add a date?

---

1 And why isn't there a website where one can enter locations of fruit trees and bushes that nobody seems to harvest? Because where we live a lot of blackberries, cherries, plums, peas, and apples are just rotting away. It’s a shame, really.
2 From Park's paper, it is not clear how many of these articles citing Wikipedia were also about Wikipedia. The examples I mentioned were dug out by Stefan.

Condensed penguins

[Img: Antarctic Connection]

During my time in Canada, the coldest temperature I recall reading off the digital display on the way back home was -28°C. I couldn't help asking myself why did humans ever settle in such hostile environment (and wtf was I doing there). But if you think Canadians are though (and Germans wimps), hear the story of the Emperor Penguin (Aptenodytes forsteri), that lives in Antarctica.

The Emperor Penguin's adaption to the cold, which can drop down to -50°C during the Antarctic winter, is plainly amazing. Feathers, fat, and their ability to increase the metabolism rate at low temperatures allow the penguins to survive. Equally amazing, but also bizarre, is the Emperor Penguin's breeding behavior.

Penguin colonies up to some thousands have nesting areas inland that are, depending on the annual ice thickness, 50-120 km away from the edge of the pack ice. At the beginning of the Antarctic Winter, some time in March or April, the penguins get out of the water and travel to their nesting areas, mostly walking or sliding on the ice. After mating, the female lays a single egg in late May or early June and passes it on to the male for incubation while she walks back to the shore.

In an environment of ice, snow, and the occasional rock the penguins can't build nests, so they balance the egg on their feet in their brood pouch. And, since there isn't much fish to find on the pack ice, they don't eat. Yes, you read that correctly: They walk a hundred kilometers, the female lays an egg and walks back a hundred kilometers, while the male sits on the egg for another 2 months, during the Antarctic Winter, in the dark, without the female, and all that without eating a thing. By the time the egg hatches, the male has fasted for almost 4 months, lost half of his body weight, and hopes for the female to return because he has nothing to feed the chick. And then he still has to walk back to the shore so he doesn't starve. But hey, my husband assembled the baby cribs!

There's a great documentary, "The March of the Penguins," telling this story:



But the penguins know some physics too!

While a single penguin is able to maintain its core body temperature in the freezing cold, this costs a lot of energy which he can't afford during his Winter fast. So what the Emperor penguins do is they form huddles. The density of the huddles increases with falling air temperature. If the huddle gets very dense, the penguins are in a nearly hexagonal arrangement. In a study from about a decade ago, researchers glued measuring devices to some penguin's lower back. They found that the temperature inside huddles can reach as much as 37.5° (Gilbert et al, arXiv:q-bio/0701051v1 [q-bio.PE]).

The penguins in these huddles do not stand still, but they move in occasional small steps which have recently been subject of another study (Zitterbart et al, PLoS ONE 6(6): e20260). The researchers shot movies of the penguin huddles and tracked the position of the birds. As you will easily notice if you read the paper, David Zitterbart is a condensed matter physicist who compares the huddling penguins to particles with an attractive interaction and the tight huddling to a jamming transition in granular materials. Just that the penguins manage to prevent jamming by coordinated movements. The little steps of the penguins propagate through the huddle like density waves. They measured densities up to 21 birds per square meter.

According to their paper, the penguins' little steps have a three-fold benefit. One is that they help the packing to get denser, much the same way like tapping a bag with ground coffee. The second is that they move the whole huddle, allowing huddles to merge and adjust position and direction. The third one is a turnover of penguins in the huddle, moving those from the outside towards the warmer inside. Though one might argue that what actually is responsible for the turnover is not the little forward steps, but the penguins on the front leaving the huddle and joining it (or another huddle) on the back. But without the forward steps, the turnover would make the huddle move backward.

The below movie from Zitterbart et al's paper (Yes, we live in the age of Harry Potter, where paper has moving pictures!) shows a time lapse of the penguin huddling (actual time about 1h):



I was very confused about the penguin turnover because in all the Emperor Penguin huddles in "The March of the Penguin" and photos I had seen only penguin backs and could not for the hell of it figure out where the penguins are supposed to go if they are all facing towards each other. So I wrote an email to David Zitterbart who kindly explained that there's two different kind of huddles that have been observed. Those that they've described in their paper, which have a forward direction, and circular ones that I had seen images of. He writes that no one really knows how the circular ones work, but they hope to find out with the next experiment.

Rehumanized

This is the previously mentioned commentary on Mark Slouka’s article “Dehumanized: When math and science rule the school” Since the article is quite lengthy, I’ve added a brief summary.

Summary

In his article “Dehumanized,” Mark Slouka argues that the US education’s focus on math and science and the neglect of the humanities spell the demise of democracy. The American education’s “long running affair with math and science” is “obsessive, exclusionary” and “altogether unhealthy.” And that is because the ways of science are “often dramatically anti-democratic.” “There are many things,” Slouka writes “math and science do well, and some they don’t. And one of the things they don’t do well is democracy.”

Referring to a quote by Dennis Overbye that “Nobody was ever sent to prison for espousing the wrong value for the Hubble constant,” Slouka complains that “To maintain its “sustainable edge,” a democracy require its citizens to actually risk something, to test the limits of the acceptable… If the value you’re espousing is one that could never get anyone, anywhere, sent to prison, then strictly democratically speaking you’re useless.” Democratically useful are only humanists because “upsetting people is arguably the very purpose of the arts and perhaps of the humanities in general.” That is also the reason, Slouka explains, totalitarian societies are skimping the dangerously upsetting humanities: “Why would a repressive regime support a force superbly designed to resist it?”

The last thing his humanist colleagues should do, Slouka says, is to succumb to the capitalist’ demand of accountability and economic utility, and attempt to fit in by justifying their existence on the enemies’ terms. “In a visible world, the invisible does not compute… in a horizontal world of “information” readily convertible to product, the verticality of wisdom has no place.” And Slouka evidently thinks wisdom is in the domain of the humanities. The trend to math and science is “the victory of whatever can be quantified over everything that can’t” and clearly one that one should oppose.

Comments

Slouka sets out to make a case against neglect of the humanities in American education and ends up calling scientists the useless couch potatoes of democratic societies. But in his arguments he makes several leaps. Most importantly, he equates “the sciences” with “the scientists” and he mixes up the role of democracy in science and the role of science for democracy, two very different things.

The process of knowledge discovery in science is not democratic. It has never been, and I hope it never will be for it would be a disaster. It is useful to think of it from a system’s perspective. Scientific progress just doesn’t work by voting. I keep saying that it would be good if we had a better understanding of its working and what feedback mechanisms are beneficial, but we know that much. That scientific knowledge discovery doesn’t operate democratically however doesn’t mean scientists don’t understand democracy or its relevance. Science teaches you to look at the evidence, to search for causal relations, correlations, and to identify and fix problems. Scientists know about the limits of predictability and the inevitability of uncertainty. They know what that statistic means and how to read that figure. They know the value of checking the references and that of reasoned argumentation. (Well, we're all human ;-)) The evidence says women are safer drivers than men. Upsetting? Where would democracy be without scientists?

But yes, scientists aren’t the first to take it to the streets if the world doesn’t run as they think it should. The people you find in the streets, those who start a revolution and throw the stones, are in the majority young unemployed males. Something to do with hormones too I guess, I’m sure somebody somewhere wrote a paper about this. The people who like their jobs, they stay in the lab and crunch the numbers because, actually, the world never runs as they think it should, but isn’t it so damned pretty if you look at it through a microscope, telescope, or binocular HMD? So I guess what Slouka is saying then is that we need the humanities because people who don’t like their job are more likely to join that demonstration tomorrow?

Okay, I’m being unfair because I actually agree with Slouka that the trend towards measuring and quantifying everything including success and knowledge gain is unhealthy. The process of measurement itself disturbs the process it is supposed to help - a problem we have discussed several times on this blog. Though, according to Slouka, a scientist like me should be positive about this trend towards reliance on metrics. Considering how divided the scientific community is over the use of any such measure for scientific success, Slouka doesn’t seem to have bothered talking to his colleagues from the science departments.

Slouka’s main point was about the American education system, and he’d done better not to overgeneralize his argument. Having grown up in Germany, I can’t judge on the quality of the American education system. Clearly, you want to teach children how the society they live in works and that includes politics, history, economics as well as all aspects of human culture. Needless to say, many of these subjects are interrelated. The impression I got during my years in the USA is that many students there have little or no idea what democracy is or how it works, and even less so do they actually know what communism, socialism, and social democracy is – and what the differences. I talked to several people who actually thought consumerism is a form of democracy, and I vividly recall talking to one guy who thought Germany is socialistic. Such confusions explain a lot of nonsense I keep reading online and are certainly not helpful to informed decision making. I am not sure though how representative that impression is. Maybe the people who talk to me are just oddballs.

And isn’t it ironic Slouka is bemoaning the American educations’ failure to produce good citizens, since to some extend I own my school education’s focus on democratic values to the Americans of the last generation? The first time some US officer said to me “I’m just following orders,” I stood in shock, having be taught a million times since Kindergarten to never, ever, justify an action by referral to an order whose purpose I cannot explain and bring in line with my conscience. After several similar incidents, I thought that’s just me till somebody told me about their German friend who in reply to the same remark by an US officer uttered promptly “That’s what the Nazi’s said.” Which, even with German accent however, fell on deaf American ears. (And that hopefully explains why I give a shit about your so-called policies.)

The other day, I came across this article by Bruce Levine listing “8 Reasons Young Americans Don’t Fight Back: How the US Crushed Youth Resistance” which you might like or not like, but point 3 “Schools That Educate for Compliance and Not for Democracy” is interesting in the context of Slouka’s article. Levine lets us know that “Upon accepting the New York City Teacher of the Year Award on January 31, 1990, John Taylor Gatto upset many in attendance by stating: “The truth is that schools don’t really teach anything except how to obey orders.””

Taken together, Slouka makes some bad points and some good points, but he makes both badly. Trying to make a case for the value of good writing, Slouka asks “Could clear writing have some relation to clear thinking?” In reply to which I want to quote Niels Bohr: “Never express yourself more clearly than you are able to think.”

This and That

Some well-written and interesting paragraphs that I came across recently.

• Steve Mirsky in Scientific American reports this amusing anecdote:
  
  

  I was reminded of preposterously precocious utterances by tiny tykes during a brief talk that string theorist Brian Greene gave at the opening of the 2011 World Science Festival in New York City on June 1. Greene said he sometimes wondered about how much information small children pick up from standard dinner-table conversation in a given home. He revealed that he got some data to mull over when he hugged his three-year-old daughter and told her he loved her more than anything in the universe, to which she replied, “The universe or the multiverse?”



• Mark Slouka's article Dehumanized: When math and science rule the school leads a fundamentally flawed argument (which I might make content of a longer post), but is one of the most beautifully written texts I've come across lately. I particularly liked this part:
  

  Consider the ritual of addressing our periodic “crises in education.” Typically, the call to arms comes from the business community. We’re losing our competitive edge, sounds the cry. Singapore is pulling ahead. The president swings into action. He orders up a blue-chip commission of high-ranking business executives (the 2006 Commission on the Future of Higher Education, led by business executive Charles Miller, for example) to study the problem and come up with “real world” solutions.
  
  Thus empowered, the commission crunches the numbers, notes the depths to which we’ve sunk, and emerges into the light to underscore the need for more accountability. To whom? Well, to business, naturally. To whom else would you account? And that’s it, more or less. Cue the curtain.



• And David Eagleman's article The Brain on Trial that argues for "a scientific approach to sentencing" gives the reader a lot to think about.
  

  Who you even have the possibility to be starts at conception. If you think genes don’t affect how people behave, consider this fact: if you are a carrier of a particular set of genes, the probability that you will commit a violent crime is four times as high as it would be if you lacked those genes. You’re three times as likely to commit robbery, five times as likely to commit aggravated assault, eight times as likely to be arrested for murder, and 13 times as likely to be arrested for a sexual offense. The overwhelming majority of prisoners carry these genes; 98.1 percent of death-row inmates do. These statistics alone indicate that we cannot presume that everyone is coming to the table equally equipped in terms of drives and behaviors.
  
  And this feeds into a larger lesson of biology: we are not the ones steering the boat of our behavior, at least not nearly as much as we believe. Who we are runs well below the surface of our conscious access, and the details reach back in time to before our birth, when the meeting of a sperm and an egg granted us certain attributes and not others. Who we can be starts with our molecular blueprints—a series of alien codes written in invisibly small strings of acids—well before we have anything to do with it. Each of us is, in part, a product of our inaccessible, microscopic history. By the way, as regards that dangerous set of genes, you’ve probably heard of them. They are summarized as the Y chromosome. If you’re a carrier, we call you a male.

Interna

Lara and Gloria are now 7 months old. During the last month, they have made remarkable progress. Both can now roll over either which way, and they also move around by pushing and pulling. They have not yet managed to crawl, but since last week they can get on all fours, and I figure it's a matter of days till they put one knee in front of the other and say good-bye to immobility. They still need a little support to sit, but they do better every day.

While the twins haven't paid any attention to each other during the first months, now they don't pay attention to anything else. Gloria doesn't take any note of me if Lara is in the room, and Lara loses all interest in lunch if Gloria laughs next door. The easiest way to stop Gloria from crying is to place her next to her sister. However, if one leaves them unattended they often scratch and hit each other. I too am covered with bruises (but hey, it rattles if I hit mommy's head!), scratches (how do you cut nails on a hand that's always in motion?), and the occasional love bite that Lara produces by furiously sucking on my upper arm (yes, it is very tasty). Gloria is still magically attracted to cables, and Lara has made several attempts to tear down the curtains.

Lara and Gloria are now at German lesson 26: da-da, ch-ch, dei-dei-dei, aga-a-gaga. It is funny that they make all these sounds but haven't yet attempted to use them for communication. They just look at us with big eyes when we speak and remain completely silent. Though they seem to understand a few words like Ja, Nein, Gut, Milch. They also clearly notice if I speak English rather than German.

For the parental reading, this month I've enjoyed Ingrid Wickelgren's article "The Miracle of Birth is that Most of Us Figure Out How to Mother - More or Less." Quoting research that shows some brain is useful for parenting too, she writes:

"To take care of a baby's needs, mom needs to be able to juggle tasks, to prioritize on the fly, rapidly, repeatedly and without a lot of downtime... Mothering tests your attention span, ability to plan, prioritize, organize and reason as much as does a day at the office."

Well, it somewhat depends on what you used to do in that office of course. But yeah, I suppose some organization skills come in handy for raising twins. I won't lie to you though, singing children's rhymes isn't quite as intellectually stimulating as going with your colleague through the new computation. But Gloria always laughs when I read to her the titles of new papers on the arXiv.

On the downside, the Globe and Mail reported the other day on "Divorce, depression: The ugly side of twins," summing up "the infant treadmill":

"Cry. Breastfeed. Bottle-feed. Burp. Breast pump. Diaper. Swaddle. Ninety minutes of baby maintenance, then 90 minutes of trying to stay on top of sleep and domestic chores, then repeat. And so on."

Oh, wait, they forgot cleaning the bottles, doing the laundry, picking up baby because she's been spitting all over herself, washing baby, changing her clothes, changing bed sheets, putting baby back into bed, putting bottles into sterilizer, put laundry into dryer, take the other baby out of bed because she's been spitting... Indeed, that's pretty much how we spent the first months. But it gets better and thanks, we're all doing just fine.

You can also disregard all the above words and just watch the below video. And if you think they're cute, don't forget they'll get cuter for two more months, so check back ;-)


PS: Oh, and please excuse the green thing in the video. New software and I haven't yet really figured out how it works.

Prediction is very difficult

Niels Bohr was a wise man. He once said: "Prediction is very difficult, especially about the future." That is especially true when it comes to predictions about future innovations, or the impact thereof.

In an article in "Bild der Wissenschaft" (online, but in German, here) about the field of so-called future studies, writer Ralf Butscher looked at some predictions made by the Fraunhofer Institute for Systems and Innovation Research (ISI) in 1998. The result is sobering: In most cases, their expert panel didn't even correctly predict the trends of already developed technologies over a time of merely a decade. They did for example predict the human genome would be sequenced by 2008. In reality, it was sequenced already in 2001. They did also predict that by 2007 a GPS-based toll-system for roads would be widely used (in Germany). For all I know no such system is on the horizon. To be fair, they said a few things that were about right, for example that beginning in 2004, flat screens would replace those with cathode-ray tubes. But by and large it seems little more than guesswork.

Don't get me wrong - it's not that I am dismissing future studies per se. It's just that when it comes to predicting innovations, history shows such predictions are mostly entertaining speculations. And then there are the occasional random hits.

I was reminded of this when I read an article by Peter Rowlett on "The unplanned impact of mathematics" in the recent issue of Nature. He introduces the reader to 7 fields of mathematics that, sometimes with centuries delay, found their use in daily life. It is too bad the article is access restricted, so let me briefly tell you what the 7 examples are. 1) The quaternions who are today used in algorithms for 3-d rotations in robotics and computer vision. 2) Riemannian geometry, today widely used in physics and plenty of applications that deal with curved surfaces. 3) The mathematics of sphere packing, used for data packing and submission. 4) Parrondo's paradox, used for example to model disease spreading. 5) Bernoulli's law of large numbers (or probability theory more broadly) and its use for insurance companies to reduce risk. 6) Topology, long thought to have no applications in the real world and its late blooming in DNA knotting and the detection of holes in mobile phone network coverage. (Note to reader: I don't know how this works. Note to self: Interesting, look this up.) 7) Fourier transform. There would be little electrodynamics and quantum mechanics without it. Applications are everywhere.

Rowlett has a call on his website, asking for more examples.

The same issue of Nature also has a commentary by Daniel Sarewitz on the NSF Criterion 2 and its update, according to which all proposals should provide a description of how they will advance national goals, for example economic competitiveness and national security. Sarewitz makes it brilliantly clear how absurd such a requirement is for many branches of research:

"To convincingly access how a particular research project might contribute to national goals could be more difficult than the proposed project itself."

And, worse, the requirement might actually hinder progress:

"Motivating researchers to reflect on their role in society and their claim to public support is a worthy goal. But to do so in the brutal competition for grant money will yield not serious analysis, but hype, cynicism and hypocrisy."

I fully agree with him. As I have argued in various earlier posts, the smartest thing to do is reducing pressure on researchers (time pressure, financial pressure, peer pressure, public pressure) and let them take what they believe is the way forward. And yes, many of them will not get anywhere. But there is nobody who can do a better job in directing their efforts than they themselves. The question is just what's the best internal evaluation system. It is puzzling to me, and also insulting, that many people seem to believe scientists are not interested in the well-being of the society they are part of, or are somehow odd people whose values have to be corrected by specific requirements. Truth is, they want to be useful as much as everybody else. If research efforts are misdirected, it is not a consequence of researchers' wrongheaded ideals, but of these clashing with strategies of survival in academia.