Life path integral

I think this web cartoon by Abstruse Goose is hilarious! (Thanks to DB for sending it to me :-)

Who is the artist? I did a quick search and didn't find anything -- is he/she deliberately anonymous (other than the Chinese characters on the upper left)?

For the perplexed: see earlier post path integrals.

Pandemics

Hmm... should I cancel my travel tomorrow to the Perimeter Institute? What exactly is the cost benefit analysis of flying to Toronto from Eugene (via Denver) right now to meet with possibly virus bearing economists and physicists from around the world? How much do those activities elevate my chances of catching H1N1, or, even worse, infecting my family?

I have no answers, although some years ago I wrote a paper on epidemics with collaborator A. Zee of KITP in Santa Barbara. That research was inspired by SARS, not H1N1, but it does have a certain timeless quality to it ;-) Astute readers will note that the bi-linear diagonalization in equation (6) resembles the transformation used on mass matrices in particle physics.

Global Spread of Infectious Diseases

http://arxiv.org/abs/cond-mat/0306628

S. Hsu, A. Zee

We develop simple models for the global spread of infectious diseases, emphasizing human mobility via air travel and the variation of public health infrastructure from region to region. We derive formulas relating the total and peak number of infections in two countries to the rate of travel between them and their respective epidemiological parameters.

From the conclusions:

One interesting conclusion from our models is that typical international mobility – the probability per unit time of international travel for a given infected individual, estimated at mi→j ∼ 10^−5 per week – is still sufficiently small that a country with well-developed public health infrastructure (effectively, a negative eigenvalue λ) can resist an epidemic even when other more populous countries experience complete saturation. In the quasi-realistic simulation 1 (figures (1),(2)), of order 10^5 infections occur in country 2, even though the disease has swept completely through country 1. In reaching this conclusion, we kept the mobility parameter fixed during the outbreak, and did not assume any draconian quarantine on international travellers arriving in country 2. Such measures would reduce the number of infections in country 2 considerably. Of course, this conclusion assumes that the public health infrastructure in country 2 remains robust during the outbreak. In the nonlinear simulation 3 (figures (6), (7)), we see that a breakdown in the medical system can lead to grave consequences.

In the case of two countries, one of which is a “reservoir” with positive eigenvalue λ_i and the other with negative eigenvalue λ_j , a good rule of thumb arising from equation (11) is that the ratio of total number of infections in the two countries is given by the fraction of infected individuals who migrate in a timescale |λ_j|^−1 , which is the “halving” time for the epidemic in country j . In our simulation 1, this timescale is about two months, and the fractional mobility over that period is ∼ 10^−4, leading to 10^5 infections in country 2 if the entire 10^9 population of country 1 is infected. The maximum number of infections at any given time in the simulation is 5 10^3 (figure (2)). If the medical system of country 2 can treat this number of patients without breaking down (entering the nonlinear regime), it can prevent a larger outbreak.

US Human Development Indices

I was struck by this table of Human Development Index values for different groups in the US. It looks like three different countries when broken out this way! There is one group clustered at 7.5 (Asians), another around 5.5 (Whites) and another around 3.5 to 4 (Blacks, Hispanics, Native Americans).

The indices are computed by this project, using US government data. See here for more, including a nice visualization with results by state, district, etc. Can the life expectancy of Native American and Latino women really be higher than for White women? Latino males also seem to have longer life expectancy than White males.



More on life expectancies of different regional and ethnic groups in the US here. (The researchers define 8 different Americas by race and geography or class.)

The gap between the life expectancy of the 3.4 million black males in high-risk urban areas in America 8 and the life expectancy for the 5.5 million Asian females in America 1 in 2001 was 20.7 y. Within the sexes, the gap between the best-off and the worst-off groups was 15.4 y for males (Asians versus blacks in high-risk urban areas) and 12.8 y for females (Asians versus low-income southern rural blacks). These gaps are 2.4 and 2.8 times those between white and black life expectancies for the nation as a whole for males and females, respectively. ...

The 12.8-y gap in life expectancy between females in Americas 1 and 7 is approximately the same as the gap between Japan, with the highest national life expectancy for females in 2001 (84.7 y), and Fiji, Nicaragua, and Lebanon [34]. Asian females in the US have a life expectancy that is 3 y higher than that of females in Japan [34]. For males, the 15.4-y gap in life expectancy between Asians (America 1) and high-risk urban blacks (America 8) is the same as between Iceland, with the highest national male life expectancy in 2001 (78.2 y), and Sao Tome, Belarus, and Uzbekistan [34]. In other words, millions of Americans, distinctly identified by their sociodemographic characteristics and place of residence, have life expectancies that are similar to some low-income developing countries (see also Figure 4B).

Neuroenhancement

Hmm... do we need drug testing for neuroenhancers?

I wouldn't be surprised to find that there are individuals who naturally function in the kind of state induced by Adderall or Provigil. Think of those hyper-productive people who start companies, write lots of books and papers and still manage to have hobbies and a social life. If a little pill helps the average guy achieve that level of capability, why not?

Provigil (modafinil) is used by the militaries of several countries, for example by fighter and bomber pilots.

New Yorker: ...The BoredAt Web sites—which allow college students to chat idly while they’re ostensibly studying—are filled with messages about Adderall. Posts like these, from the BoredAtPenn site, are typical: “I have some Adderall—I’m sitting by room 101.10 in a grey shirt and headphones”; “I have Adderall for sale 20mg for $15”; “I took Adderall at 8 p.m., it’s 6:30 a.m. and I’ve barely blinked.” On the Columbia site, a poster with an e-mail address from CUNY complains that her friends take Adderall “like candy,” adding, “I don’t want to be at a disadvantage to everyone else. Is it really that dangerous? Will it fuck me up? My grades weren’t that great this year and I could do with a bump.” A Columbia student responds, “It’s probably not a good idea if you’re not prescribed,” but offers practical advice anyway: “Keep the dose normal and don’t grind them up or snort them.” Occasional dissents (“I think there should be random drug testing at every exam”) are drowned out by testimonials like this one, from the BoredAtHarvard site: “I don’t want to be a pusher or start people on something bad, but Adderall is AMAZING.”

...Zack, who has a book being published this summer, called “The Neuro Revolution,” said, “We live in an information society. What’s the next form of human society? The neuro-society.” In coming years, he said, scientists will understand the brain better, and we’ll have improved neuroenhancers that some people will use therapeutically, others because they are “on the borderline of needing them therapeutically,” and others purely “for competitive advantage.”

Zack explained that he didn’t really like the term “enhancement”: “We’re not talking about superhuman intelligence. No one’s saying we’re coming out with a pill that’s going to make you smarter than Einstein! . . . What we’re really talking about is enabling people.” He sketched a bell curve on the back of a napkin. “Almost every drug in development is something that will take someone who’s working at, like, forty per cent or fifty per cent, and take them up to eighty,” he said.

...Paul Phillips was unusual for a professional poker player. When he joined the circuit, in the late nineties, he was already a millionaire: a twenty-something tech guy who had started off writing software, helped found an Internet portal called go2net, and cashed in at the right moment. He was cerebral and, at times, brusque. His nickname was Dot Com. ...Most unusual of all, Phillips talked freely about taking prescription drugs—Adderall and, especially, Provigil—in order to play better cards.

He first took up the game in 1995, when he was in college, at U.C. San Diego. He recalled, “It was very mathematical, but you could also inject yourself into the game and manipulate the other guy with words”—more so than in a game like chess. Phillips soon felt that he had mastered the strategic aspects of poker. The key variable was execution. At tournaments, he needed to be able to stay focussed for fourteen hours at a stretch, often for several days, but he found it difficult to do so. In 2003, a doctor gave him a diagnosis of A.D.H.D., and he began taking Adderall. Within six months, he had won $1.6 million at poker events—far more than he’d won in the previous four years. Adderall not only helped him concentrate; it also helped him resist the impulse to keep playing losing hands out of boredom. In 2004, Phillips asked his doctor to give him a prescription for Provigil, which he added to his Adderall regimen. He took between two hundred and three hundred milligrams of Provigil a day, which, he felt, helped him settle into an even more serene and objective state of mindfulness; as he put it, he felt “less like a participant than an observer—and a very effective one.” Though Phillips sees neuroenhancers as essentially steroids for the brain, they haven’t yet been banned from poker competitions.

Last summer, I visited Phillips in the high-desert resort town of Bend, Oregon, where he lives with his wife, Kathleen, and their two daughters, Ivy and Ruby. Phillips, who is now thirty-six, seemed a bit out of place in Bend, where people spend a lot of time skiing and river rafting. Among the friendly, faithfully recycling locals, he was making an effort to curb his caustic side. Still, when I first sent Phillips an e-mail asking him to explain, more precisely, how Provigil affected him, he couldn’t resist a smart-ass answer: “More precisely: after a pill is consumed, tiny molecules are absorbed into the bloodstream, where they eventually cross the blood-brain barrier and influence the operation of the wetware up top.”

In person, he was more obliging. He picked me up at the Bend airport driving a black convertible BMW, and we went for coffee at a cheery café called Thump. Phillips wore shorts and flip-flops and his black T-shirt displayed an obscure programming joke. “Poker is about sitting in one place, watching your opponents for a long time, and making better observations about them than they make about you,” he said. With Provigil, he “could process all the information about what was going on at the table and do something about it.” Though there is no question that Phillips became much more successful at poker after taking neuroenhancers, I asked him if his improvement could be explained by a placebo effect, or by coincidence. He doubted it, but allowed that it could. Still, he said, “there’s a sort of clarity I get with Provigil. With Adderall, I’d characterize the effect as correction—correction of an underlying condition. Provigil feels like enhancement.” And, whereas Adderall made him “jittery,” Provigil’s effects were “completely limited to my brain.” He had “zero difficulty sleeping.”

...Drugs like Ritalin and Adderall work, in part, by elevating the amount of dopamine in the brain. Dopamine is something you want just enough of: too little, and you may not be as alert and motivated as you need to be; too much, and you may feel overstimulated. Neuroscientists have discovered that some people have a gene that leads the brain to break down dopamine faster, leaving less of it available; such people are generally a little worse at certain cognitive tasks. People with more available dopamine are generally somewhat better at the same tasks. It makes sense, then, that people with naturally low dopamine would benefit more from an artificial boost.

...Zack Lynch, of NeuroInsights, gave me a rationale for smart pills that I found particularly grim. “If you’re a fifty-five-year-old in Boston, you have to compete with a twenty-six-year-old from Mumbai now, and those kinds of pressures are only going to grow,” he began. Countries other than the U.S. might tend to be a little looser with their regulations, and offer approval of new cognitive enhancers first. “And if you’re a company that’s got forty-seven offices worldwide, and all of a sudden your Singapore office is using cognitive enablers, and you’re saying to Congress, ‘I’m moving all my financial operations to Singapore and Taiwan, because it’s legal to use those there,’ you bet that Congress is going to say, ‘Well, O.K.’ It will be a moot question then. It would be like saying, ‘No, you can’t use a cell phone. It might increase productivity!’ ”

...Paul McHugh, a psychiatrist at Johns Hopkins University, has written skeptically about cosmetic neurology. In a 2004 essay, he notes that at least once a year in his private practice he sees a young person—usually a boy—whose parents worry that his school performance could be better, and want a medication that will assure it. In most of these cases, “the truth is that the son does not have the superior I.Q. of his parents,” though the boy may have other qualities that surpass those of his parents—he may be “handsome, charming, athletic, graceful.” McHugh sees his job as trying to get the parents to “forget about adjusting him to their aims with medication or anything else.”

...Of course, the idea behind mind-hacking isn’t exactly new. Fortifying one’s mental stamina with drugs of various kinds has a long history. Sir Francis Bacon consumed everything from tobacco to saffron in the hope of goosing his brain. Balzac reputedly fuelled sixteen-hour bouts of writing with copious servings of coffee, which, he wrote, “chases away sleep, and gives us the capacity to engage a little longer in the exercise of our intellects.” Sartre dosed himself with speed in order to finish “Critique of Dialectical Reason.”

New York Times nearing bankruptcy

They need some real business leadership, and they need it now. The Grey Lady is going down for the count thanks to the internet, craigslist and the recession. Will there be a bailout?

BusinessInsider: As expected, the New York Times's business operations began burning cash this quarter (until now, they had remained cash-flow positive). The company has recently made several wise moves that have postponed the date at which it will run out of cash. But the situation is still critical.

At the current rate of cash consumption, assuming no one-time expenses (highly unlikely), we estimate that the company will max out its current borrowing capacity in 4 quarters. At that point, it will owe about $1.2 billion in debt. This estimate does not include any payments on the company's $600+ million pension and benefit obligation, of which $181 million is due next year.

The bottom line: The New York Times Company remains on the brink of insolvency. There are also at least $1.5 billion of claims ahead of common shareholders of the company's assets should it file for bankruptcy. ...

Financial crisis and economics at Perimeter

I'll be attending an interdisciplinary conference at the Perimeter Institute, May 1-4: The Economic Crisis and its Implications for The Science of Economics. It should be a combustible mix of personalities ;-)

I give the economists credit for entering the lion's den of theoretical physicists. Here is how J. DOYNE FARMER, of the Santa Fe Institute and Prediction Company, described a meeting of this type that occurred 20 years ago.

With some justification, many economists think that the entry of physicists into their world reflects merely audacity, hubris, and arrogance. Physicists are not known for their humility, and some physicists have presented their work in a manner that plays into this stereotype. The cultural barrier between the two groups will be difficult to overcome. This schism was already evident at a conference held at the Santa Fe Institute in 1988 titled “The Economy as an Evolving Complex System.” Roughly half the participants were economists and the other half physicists. Although many of the physicists were largely ignorant of economics, that did not prevent them from openly criticizing the economists. At one point, Nobel laureate Phil Anderson said, “You guys really believe that?” At another point, Larry Summers (now Secretary of the Treasury) accused physicists of having a “Tarzan complex.” This was not just a turf war. Whether due to nature or nurture, this conference clearly showed that there is a deep epistemological divide between physicists and economists that is difficult to cross.

The first day talks are listed below. Perimeter is usually good about putting their talks online, so you can probably enjoy them yourself without schlepping all the way to Canada :-)

9:15 - 10:00 Eric Weinstein Conference Overview

10:00 - 10:45 Nouriel Roubini

11:10 - 11:55 Nassim Taleb

11:55 - 12:40 W. Brian Arthur Neoclassical Economics and its Policy Biases: Is there an alternative?

12:40 - 1:00 Panel Discussion with Speakers

1:00 - 2:30 Lunch Break

2:30 - 3:15 Emanuel Derman Scientists, Sciensters, Anti-Scientists & Economics

3:15 - 4:00 Andrew Lo The Adaptive Markets Hypothesis and Financial Crisis

4:15 - 5:00 Richard Alexander

5:00 - 6:00 Panel Discussion with Speakers and Wrap Up

50 years of John Searle at Berkeley

To find a 90 minute podcast of this gathering, which is remarkable for the quality of the speeches given in honor of philosopher John Searle, search under "searle 50 berkeley" at iTunes U (or follow this link).

John Searle’s 50 Years at Berkeley—A Celebration

A celebration of John Searle’s 50 years of distinguished service to the UC Berkeley campus, with reflections by Tom Nagel, Barry Stroud, Robert Cole, Alex Pines, Peter Hanks, and Maya Kronfeld.

While I disagree strongly with Searle's most famous philosophical construct -- the so called Chinese room argument against strong AI (see also here) -- I've always found his writing and argumentation to be exceptionally clear, at least for a philosopher ;-)

See also Paul Graham against philosophy.

The Quiet Coup

How the financial industry captured our government, and how that capture continues unabated despite the crisis. Author Simon Johnson is a former chief economist at the IMF. To him, America's situation is the all too familiar one of a banana republic that has been run aground by its oligarchs.

I doubt Johnson will be making millions of dollars per year consulting for a hedge or private equity fund anytime soon, the way that Larry Summers or Bill Clinton or GHWB have, or that Obama someday will.

The Atlantic: ...In its depth and suddenness, the U.S. economic and financial crisis is shockingly reminiscent of moments we have recently seen in emerging markets (and only in emerging markets): South Korea (1997), Malaysia (1998), Russia and Argentina (time and again). In each of those cases, global investors, afraid that the country or its financial sector wouldn’t be able to pay off mountainous debt, suddenly stopped lending. And in each case, that fear became self-fulfilling, as banks that couldn’t roll over their debt did, in fact, become unable to pay. This is precisely what drove Lehman Brothers into bankruptcy on September 15, causing all sources of funding to the U.S. financial sector to dry up overnight. Just as in emerging-market crises, the weakness in the banking system has quickly rippled out into the rest of the economy, causing a severe economic contraction and hardship for millions of people.

But there’s a deeper and more disturbing similarity: elite business interests—financiers, in the case of the U.S.—played a central role in creating the crisis, making ever-larger gambles, with the implicit backing of the government, until the inevitable collapse. More alarming, they are now using their influence to prevent precisely the sorts of reforms that are needed, and fast, to pull the economy out of its nosedive. The government seems helpless, or unwilling, to act against them.

Top investment bankers and government officials like to lay the blame for the current crisis on the lowering of U.S. interest rates after the dotcom bust or, even better—in a “buck stops somewhere else” sort of way—on the flow of savings out of China. Some on the right like to complain about Fannie Mae or Freddie Mac, or even about longer-standing efforts to promote broader homeownership. And, of course, it is axiomatic to everyone that the regulators responsible for “safety and soundness” were fast asleep at the wheel.

But these various policies—lightweight regulation, cheap money, the unwritten Chinese-American economic alliance, the promotion of homeownership—had something in common. Even though some are traditionally associated with Democrats and some with Republicans, they all benefited the financial sector. Policy changes that might have forestalled the crisis but would have limited the financial sector’s profits—such as Brooksley Born’s now-famous attempts to regulate credit-default swaps at the Commodity Futures Trading Commission, in 1998—were ignored or swept aside.

The financial industry has not always enjoyed such favored treatment. But for the past 25 years or so, finance has boomed, becoming ever more powerful. The boom began with the Reagan years, and it only gained strength with the deregulatory policies of the Clinton and George W. Bush administrations. Several other factors helped fuel the financial industry’s ascent. Paul Volcker’s monetary policy in the 1980s, and the increased volatility in interest rates that accompanied it, made bond trading much more lucrative. The invention of securitization, interest-rate swaps, and credit-default swaps greatly increased the volume of transactions that bankers could make money on. And an aging and increasingly wealthy population invested more and more money in securities, helped by the invention of the IRA and the 401(k) plan. Together, these developments vastly increased the profit opportunities in financial services.


...Of course, the U.S. is unique. And just as we have the world’s most advanced economy, military, and technology, we also have its most advanced oligarchy.

In a primitive political system, power is transmitted through violence, or the threat of violence: military coups, private militias, and so on. In a less primitive system more typical of emerging markets, power is transmitted via money: bribes, kickbacks, and offshore bank accounts. Although lobbying and campaign contributions certainly play major roles in the American political system, old-fashioned corruption—envelopes stuffed with $100 bills—is probably a sideshow today, Jack Abramoff notwithstanding.

Instead, the American financial industry gained political power by amassing a kind of cultural capital—a belief system. Once, perhaps, what was good for General Motors was good for the country. Over the past decade, the attitude took hold that what was good for Wall Street was good for the country. The banking-and-securities industry has become one of the top contributors to political campaigns, but at the peak of its influence, it did not have to buy favors the way, for example, the tobacco companies or military contractors might have to. Instead, it benefited from the fact that Washington insiders already believed that large financial institutions and free-flowing capital markets were crucial to America’s position in the world.

One channel of influence was, of course, the flow of individuals between Wall Street and Washington. Robert Rubin, once the co-chairman of Goldman Sachs, served in Washington as Treasury secretary under Clinton, and later became chairman of Citigroup’s executive committee. Henry Paulson, CEO of Goldman Sachs during the long boom, became Treasury secretary under George W.Bush. John Snow, Paulson’s predecessor, left to become chairman of Cerberus Capital Management, a large private-equity firm that also counts Dan Quayle among its executives. Alan Greenspan, after leaving the Federal Reserve, became a consultant to Pimco, perhaps the biggest player in international bond markets.

These personal connections were multiplied many times over at the lower levels of the past three presidential administrations, strengthening the ties between Washington and Wall Street. It has become something of a tradition for Goldman Sachs employees to go into public service after they leave the firm. The flow of Goldman alumni—including Jon Corzine, now the governor of New Jersey, along with Rubin and Paulson—not only placed people with Wall Street’s worldview in the halls of power; it also helped create an image of Goldman (inside the Beltway, at least) as an institution that was itself almost a form of public service.

Wall Street is a very seductive place, imbued with an air of power. Its executives truly believe that they control the levers that make the world go round. A civil servant from Washington invited into their conference rooms, even if just for a meeting, could be forgiven for falling under their sway. Throughout my time at the IMF, I was struck by the easy access of leading financiers to the highest U.S. government officials, and the interweaving of the two career tracks. I vividly remember a meeting in early 2008—attended by top policy makers from a handful of rich countries—at which the chair casually proclaimed, to the room’s general approval, that the best preparation for becoming a central-bank governor was to work first as an investment banker.

A whole generation of policy makers has been mesmerized by Wall Street, always and utterly convinced that whatever the banks said was true. Alan Greenspan’s pronouncements in favor of unregulated financial markets are well known. Yet Greenspan was hardly alone. This is what Ben Bernanke, the man who succeeded him, said in 2006: “The management of market risk and credit risk has become increasingly sophisticated. … Banking organizations of all sizes have made substantial strides over the past two decades in their ability to measure and manage risks.”

Of course, this was mostly an illusion. Regulators, legislators, and academics almost all assumed that the managers of these banks knew what they were doing. In retrospect, they didn’t. AIG’s Financial Products division, for instance, made $2.5 billion in pretax profits in 2005, largely by selling underpriced insurance on complex, poorly understood securities. Often described as “picking up nickels in front of a steamroller,” this strategy is profitable in ordinary years, and catastrophic in bad ones. As of last fall, AIG had outstanding insurance on more than $400 billion in securities. To date, the U.S. government, in an effort to rescue the company, has committed about $180 billion in investments and loans to cover losses that AIG’s sophisticated risk modeling had said were virtually impossible.

Wall Street’s seductive power extended even (or especially) to finance and economics professors, historically confined to the cramped offices of universities and the pursuit of Nobel Prizes. As mathematical finance became more and more essential to practical finance, professors increasingly took positions as consultants or partners at financial institutions. Myron Scholes and Robert Merton, Nobel laureates both, were perhaps the most famous; they took board seats at the hedge fund Long-Term Capital Management in 1994, before the fund famously flamed out at the end of the decade. But many others beat similar paths. This migration gave the stamp of academic legitimacy (and the intimidating aura of intellectual rigor) to the burgeoning world of high finance.

As more and more of the rich made their money in finance, the cult of finance seeped into the culture at large. Works like Barbarians at the Gate, Wall Street, and Bonfire of the Vanities—all intended as cautionary tales—served only to increase Wall Street’s mystique. Michael Lewis noted in Portfolio last year that when he wrote Liar’s Poker, an insider’s account of the financial industry, in 1989, he had hoped the book might provoke outrage at Wall Street’s hubris and excess. Instead, he found himself “knee-deep in letters from students at Ohio State who wanted to know if I had any other secrets to share. … They’d read my book as a how-to manual.”

James Yang graphic art

A colleague introduced me to the artist James Yang, whose work seems to have a special appeal for geeky scientists like me. Below are a couple of nice images from his portfolio, with my own suggested captions :-)


"Physics department" (Peter Galison: ''My question is not how different scientific communities pass like ships in the night,'' he wrote in Image and Logic. ''It is rather how, given the extraordinary diversity of the participants in physics -- cryogenic engineers, radio chemists, algebraic topologists, prototype tinkerers, computer wizards, quantum field theorists -- they speak to each other at all.'' :-)




"Discovering China"



"The biotech century"

Quantum books

Two book recommendations, covering recent developments in quantum physics.

1) A popular book by first time author Louisa Gilder (daughter of futurist George Gilder), who began as a physics major at Dartmouth, but switched to English after two years. Nevertheless she retained her interest in quantum physics and arranged an independent study on the topic of entanglement that led (seven or so years later) to The Age of Entanglement. The book is excellent and covers important topics of the last 50 years that have not yet made their way into historical treatments of quantum mechanics: Bohmian mechanics, Bell's theorem, entanglement, quantum cryptography and teleportation, etc. I picked it up in the bookstore not expecting very much, but a casual glance at the later chapters convinced me it was worth reading. While none of the physics was new to me, many of the human stories behind the developments were not just new, but fascinating.

Here is a nice interview with Gilder.

One of my favorite quotes from the book is from experimentalist Anton Zeilinger: The boundary of classical and quantum is just a question of money. If we can create superpositions of buckyballs today will we someday do it with live viruses? :-)

Amazingly, there is no mention of decoherence or Everett's work in the book, despite a long discussion concerning Bell and the Against Measurement debate! (See related links here.)

2) For serious quantum mechanics who want to understand modern theoretical and experimental developments related to entanglement, decoherence and macroscopic superpositions, I recommend the book Exploring the Quantum by S. Haroche and J.-M. Raimond.

The counter-intuitive aspects of quantum physics have been for long illustrated by thought experiments, from Einstein's photon box to Schrodinger's cat. These experiments have now become real, with single particles--electrons, atoms or photons--directly unveiling the weird features of the quantum. State superpositions, entanglement and complementarity define a novel quantum logic which can be harnessed for information processing, raising great hopes for applications. This book describes a class of such thought experiments made real. Juggling with atoms and photons confined in cavities, ions or cold atoms in traps, is here an incentive to shed a new light on the basic concepts of quantum physics. Measurement processes and decoherence at the quantum-classical boundary are highlighted.

Life magazine photos

Have a look at this amazing repository of classic photographs at Life.com. Below are a few that came up when I searched under Oppenheimer, von Neumann and Stalingrad. The caption for the bottom photograph is "1st February 1943: German commander of the 6th Army, Field Marshal Friedrich von Paulus (1890 - 1957), surrendering after his troops were besieged at Stalingrad."

Merton on the financial crisis

This talk is long but very good. If you are impatient you can skip to the last 3 minutes where Merton answers a question about the CDS market that has been widely discussed. He points out the value for real world companies of being able to transfer credit risk as opposed to the narrower application of insuring a bond that they actually own.

The central point of the first part of the talk -- the embedded put option in a plain vanilla loan, and associated nonlinearities -- is nice but I don't think it is as essential to the current crisis as he suggests. (It's obviously in his interests to downplay the complexity of new financial instruments relative to traditional ones. The difference, of course, is that we've had much more time to get used to the traditional ones and build the proper safeguards and regulatory systems.) Merton is refreshingly modest about his understanding of the complex causes of the crisis. At one point he notes that the post mortem investigation into the crisis is unlikely to produce a Feynman moment, in which someone holds up an O-ring that caused the disaster!

Here is another link in case the player below doesn't work for you.





I sat in on Merton's graduate class on options pricing theory at Harvard in the early 1990s. I still have the lecture notes and a black paperback copy of Continuous Time Finance. He seemed much more confident at the time, but of course that was before LTCM :-)

I was one of the first people to recast options pricing theory into the language of Feynman path integrals. (You don't need the power of quantum field theory for this; the log of the price of the underlying security is just the position of a particle in simple 1D quantum mechanics in imaginary time -- i.e., it's just Brownian motion.) A friend of mine had been assigned a thesis project by Andy Lo at MIT, to price a certain type of exotic, path dependent option sold by Citibank. Lo didn't know the option could be priced in closed form (neither did Citi, it turns out); he asked my friend to do it numerically by brute force Monte Carlo. Using path integrals I found an exact expression for my friend, which agreed perfectly with his simulations.

Sugar Daddies: MIT grad starts high end prostitution web site ;-)

The Times magazine has a long piece about SeekingArrangement.com, a web site that helps "sugar babies" find rich "sugar daddies" :-) On the site there are 10 babies for every daddy.

I would say that a large number of financially successful guys I have known have analyzed the dating situation (usually over a few drinks) and come to the same conclusions as the users and creator of the site. (See further down the excerpt, and especially the guy called Sam.) I don't personally know very many women who have analyzed it from the other side and come to the sugar baby perspective (or at least will admit to it), but there are obviously lots out there. See the sugar daddy blog for hundreds of comments from sugar babies.

For the Asian version of all this, see Enjo kosai, or "compensated dating" in Japanese (also here and here).

NYTimes: AT FIRST GLANCE, the Web site SeekingArrangement.com seems like any other dating site. Most of the men are looking for fit, sexy women, and most of the women want nice guys who can make them smile and laugh. But if eHarmony or Match.com is a chatty social mixer, Seeking Arrangement is a down-and-dirty marketplace where older moneyed men and cute young women engage in brutally frank transactions. They’re not searching for longtime soul mates; they want no-strings-attached “arrangements” that trade in society’s most valued currencies: wealth, youth and beauty. In the cheesy lexicon of the site, they are “sugar daddies” and “sugar babies.”

There’s the 18-year-old from France asking for $5,000 to $10,000 a month from “a mentor who can provide me with the finer things in life and keep me happy!” And the 49-year-old investor from upstate New York willing to pay $5,000 a month for a “daytime playmate” for “intense connection without commitment.” Critics say the site is at best a convenience store for adulterers and at worst a virtual brothel, but Brandon Wade, Seeking Arrangement’s 38-year-old founder and chief executive, is unperturbed by the criticism. “We stress relationships that are mutually beneficial,” he says. ...

ABOUT 30 PERCENT OF ARRANGEMENTS on the site involve the daddy paying an “allowance,” usually a thousand or two a month, though the site claims some reach $10,000. The rest provide the baby with incidental cash, shopping sprees, gifts, travel or the fleeting illusion that theirs is a high-end, easy life. “I get flown to whatever city I want,” wrote a North Carolina college student, who goes by the name gurlnextdoor on the site’s blog, a mix between an online support group and a kaffeeklatsch. “He pays for it, takes me shopping, we talk, laugh, go out to eat and do whatever we want to do for our days together. . . . I don’t bring up mundane problems about my home life, and he does the same. . . . If I wanted someone to talk to about my life problems, I’d get a boyfriend or a therapist.”

...In fact, Seeking Arrangement pays to have its ads pop up on search engines whenever someone types in “student loan,” “tuition help,” “college support” or “help with rent.” Lola was one of many to stumble on the site that way, when — behind on her rent and tuition and down to one meal a day — she Googled “student loan.” What popped up was hardly what she expected, but she was willing to try almost anything to stay in school.

...Whether sugar relationships amount to prostitution is hotly debated among the site’s members. “Let’s get real here,” wrote GoldenGate on the blog. “I’m with a guy who’s old enough to be my dad, short and balding. Not to mention his other shortcomings, ahem. But he gives me a great big fat allowance every month. If that wasn’t there, we wouldn’t be together.”

Others on the blog were shocked, saying they could never be with a man, even a rich one, if they weren’t somehow attracted to him. Indeed, most go to considerable effort to distinguish between “sugar” and prostitution. (Legally, at least, they are right; since the 1970s, courts have ruled that as long as the woman is paid for some service besides sex — housecleaning, companionship — the arrangement is not the equivalent of prostitution.) They say being a sugar baby is no more an occupation than dating is, especially when the goal of dating is to find a rich boyfriend or a wealthy husband. ...

Some sugar babies also insist that wives who stay in miserable marriages for an American Express black card, mansion or country-club membership are more like prostitutes than they are. And yet the blatant financial transactions leave many uneasy.

...a 22-year-old named Mercedes told me, “I don’t see how people can view this as exploitation.” Mercedes is a junior who pays her own tuition at a Georgia university. She has had six sugar daddies in the past year to supplement her wages busing tables and washing dishes at a bar. “I could go out and work three jobs and still go to school and probably make decent grades, but is that really what I want to do? I make more money this way, and I have a lot more fun because I get to go out to concerts, go shopping, see movies and make money off of it. If instead of this I was just dating a rich guy, it’d be almost the same thing, and society wouldn’t look down on that. You know with a sugar daddy that they’re spending a lot of money on you and they clearly want something in return, but is that really any different than how it is with a boyfriend?”

BRANDON WEY GOT THE IDEA for the site from his own dissatisfying love life as an M.I.T. student and then as a well-off but awkward tech executive. Traditional dating Web sites were no help. “It was difficult to advertise the assets I had compared to hundreds of thousands of guys who had better looks or better pickup lines,” says Wey, now married to a woman 13 years younger than he is, whom he met before the site went live. “I needed to find a way to put myself at the front of the line.”

One sugar daddy whose screen name is Sam has tried long-term girlfriends, mistresses, prostitutes and a brief marriage. ... Sam’s profile on Seeking Arrangement is audacious. He advertises for a woman who is “drop-dead beautiful, sexy, fun and elegantly mannered in a fancy setting. She must turn heads . . . and make me the envy of the crowd.” ... When I asked to chat in person, Sam suggested meeting at CORE, a private Manhattan club where membership is by invitation only and costs $65,000 the first year and where Sam’s assent was required before I could be admitted. Sitting alone at a long conference table in a room set aside for him, he looked utterly unremarkable, a man of average height with a buzz cut and an aloof air. But once Sam got talking, he became affable and witty, especially as he described his unorthodox history with women. He started college when most kids his age were still in middle school. “When you go to college at that age, you’re pretty undatable,” he said. “I was somewhere between a curiosity, a mascot and a friend. I tutored freshman physics and calculus so I could at least be near women. Of course, all they’d do is talk about their boyfriends.”

He has an almost mathematical approach to assessing relationships, and once even computed the costs for a girlfriend, mistress, prostitute and wife — mistresses turn out to be most expensive by the hour; wives, by the year; girlfriends are cheapest all around. But he’s not as calculating as he seems. In fact, he concluded there’s little correlation between cost and quality. Still, he is relentlessly searching for an algorithm that will predict relationships’ success.

Sam is also more determined than most to try separating a sugar baby’s affection and the money she’s paid to provide it. In his arrangements, he says, he establishes a trust in the woman’s name that pays a monthly stipend of at least $5,000 for the length of their contract. If the woman decides to quit sleeping with him at any point, he may quit serving as adviser and pamperer, but the stipend continues regardless. “If I didn’t do that, then it’s like a leash I’m putting on somebody, and that seems really unfair,” he said. “Besides, then I’d never know what the relationship was really about.”

Sam runs these relationships with an explicit business plan, a set budget, measurable goals and quarterly reviews. From the outset, the contract has an end date. It’s a brilliant, if contrived, way to protect his pride. The contract specifies that the romance and sex are to end by the preset date, so there’s no break up, no rejection, no bruised ego. She’s not dumping him; the gig’s just over.

Rationality vs Intelligence

I can believe that intelligence is somewhat uncorrelated with rational behavior (see below for definition; to some extent it is merely the requirement of self-consistency). But do smarter people become more rational once their foibles are revealed to them?

Rationality vs Intelligence: In 2002, the cognitive scientist Daniel Kahneman of Princeton University won the Nobel Prize in Economics for work done with his longtime collaborator Amos Tversky (who died in 1996).

Their work had to do with judgment and decision-making ― what makes our thoughts and actions rational or irrational. They explored how people make choices and assess probabilities, and uncovered basic errors that are typical in decision-making.

The thinking errors they uncovered are not trivial mistakes in a parlor game. To be rational means to adopt appropriate goals, take the appropriate action given one's goals and beliefs, and hold beliefs that are commensurate with available evidence. It means achieving one's life goals using the best means possible.

To violate the thinking rules examined by Kahneman and Tversky thus has the practical consequence that we are less satisfied with our lives than we might be.

Research conducted in my own laboratory has indicated that there are systematic individual differences in the judgment and decision-making skills that Kahneman and Tversky studied.

Ironically, the Nobel Prize was awarded for studies of cognitive characteristics that are entirely missing from the most well-known mental assessment device in the behavioral sciences: intelligence tests.

Scientists and laypeople alike tend to agree that "good thinking" encompasses sound judgment and decision-making ― the type of thinking that helps us achieve our goals. Yet assessments of such good (rational) thinking are nowhere to be found on IQ tests.

Intelligence tests measure important things, but they do not assess the extent of rational thought. This might not be such a grave omission if intelligence were a strong predictor of rational thinking.

But my research group found just the opposite: it is a mild predictor at best, and some rational thinking skills are totally dissociated from intelligence.

To an important degree, intelligence tests determine the academic and professional careers of millions of people in many countries.

Children are given intelligence tests to determine eligibility for admission to school programs for the gifted. Corporations and the military depend on assessment and sorting devices that are little more than disguised intelligence tests.

Perhaps some of this attention to intelligence is necessary, but what is not warranted is the tendency to ignore cognitive capacities that are at least equally important: the capacities that sustain rational thought and action.

Critics of intelligence tests have long pointed out that the tests ignore important parts of mental life, mainly non-cognitive domains such as socio-emotional abilities, empathy, and interpersonal skills.

But intelligence tests are also radically incomplete as measures of cognitive functioning, which is evident from the simple fact that many people display a systematic inability to think or behave rationally despite having a more than adequate IQ.

For a variety of reasons, we have come to overvalue the kinds of thinking skills that intelligence tests measure and undervalue other important cognitive skills, such as the ability to think rationally.

Psychologists have studied the major classes of thinking errors that make people less than rational.

They have studied people's tendencies to show incoherent probability assessments; to be overconfident in knowledge judgments; to ignore the alternative hypothesis; to evaluate evidence with a "my side" bias; to show inconsistent preferences because of framing effects; to over-weigh short-term rewards at the expense of long-term well-being; to allow decisions to be affected by irrelevant context; and many others.

All of these categories of failure of rational judgment and decision-making are very imperfectly correlated with intelligence ― meaning that IQ tests tend not to capture individual differences in rational thought.

Intelligence tests measure mental skills that have been studied for a long time, whereas psychologists have only recently had the tools to measure the tendencies toward rational and irrational thinking. ...

Lawyerland

What lawyers talk about when they talk about law. Something I'm reading at the moment. Joseph is no Mamet but it's worth a look.



Review from Amazon:

Joseph, a poet and law professor at St. John's University in New York, sat down (mostly at meals) with several lawyers of his acquaintance and distilled their conversations into stories that read like radio mini-plays. Indeed, the frank, high-pitched language verges on Mamet. "Reasonable doubt? They go fucking bananas!" declares a weary criminal lawyer of the law-fascinated juries he encounters. A corporate lawyer offers some grim truth: "What we do is determined by who pays us." A loquacious judge, after damning lawyers as liars, finally tells her interviewer of a mind-boggling attempted-murder case involving a husband and wife that resonates with painful clarity. A torts lawyer explicates the world of medical malpractice, where transactional costs trump other considerations: "The public believes in fairness. Well, what's fair for me isn't fair for you." A black lawyer tells a hilarious story about a black law partner who, exasperated by a condescending white client, finally "[g]oes and violates Negro Rule Number One," i.e., never act crazy: act smart. The noirish world that Joseph creates should serve as a tart reminder to practicing lawyers and as a cautionary tale for the aspiring; others may wish for stories with a larger dose of narrative and epiphany.

My favorite bit so far is on page 49:

These people are serious. This client -- Cal Tech. Phi Beta Kappa. He's 33 years old and he's already made two -- going on his third -- separate fortunes in computers. He does not care for lawyers. ... He'll point at a lawyer and say, "Look how twisted, how soft, how false his face is."

A physicist from Iran

We have a sabbatical visitor in our institute who is professor of theoretical physics in Iran. He did his doctoral work at Oxford but this is his first time in the US. He kindly agreed to answer some questions for this blog. I'll try to follow up with more in the future; I realize these first questions are a bit superficial.

Q: How would you describe the scientific situation today in Iran? Do you feel researchers there are up to date on current progress, or is there a gap? Is the government serious about scientific research?

Almost all governments of developing countries have a lot of financial problems and they have to choose where to spend money.

In a few countries such as India and China, the government spends a lot of money for research on purely scientific projects. Other countries don't spend so much money as they have lots of problems to solve. In Iran the financial situation is not so good and there is not enough money to solve these kinds of problem and so scientific research is not similar to the west. I am sure there is gap in some topics.


Q: How popular is physics in Iran (say, versus engineering)? What do the brightest students in Iran tend to study?

Many high school students like physics, however they don't choose physics as their first choice.

The brightest students choose: Medical subjects, Electrical eng., Mechanical eng. and Civil eng. because they may get a job more easily in the future. I mean these subjects are more secure from the economical point of view. Someone with a BSc or even a PhD in physics won't be able to find a job easily.


Q: What is the attitude of scientists in Iran about nuclear weapons development?

Nobody likes nuclear weapons and everyone wants to live in a world without nuclear arms. People in Iran hate war. Iran had 8 years of war with Iraq and people don't like war as they know its consequences. People in Iran are against nuclear weapons.


Q: What is the general attitude of scientists towards the US, the West, etc.?

They like to have scientific relations with all countries.


Q: Can you characterize academic ties to developing countries like India and China? Comparable to those between Iran and the West? Increasing faster?

There is not too much academic interaction between Iran and India or China. There is a little bit more interaction between Iranian scientists and western countries.


Q: The same question for economic ties.

There are strong economic ties between Iran and China (not with India). This is not strange: you go anywhere in the world for shopping and you will see "made in china" almost everywhere. However, economic relations between Iran and Europe are much stronger.

Theories of games

While visiting Vanderbilt over spring break, I discovered that astrophysicist Bob Scherrer and I share a couple of boyhood interests: science fiction and strategic games. Bob actually writes science fiction, and still plays board games with his kids, whereas I switched long ago to "serious" literature and don't play or design games anymore.

But from age 11 to 14 or so (basically until I hit puberty and discovered girls), I spent every Saturday at the local university simulation gaming club, playing games like Panzergruppe Guderian, Starship Troopers or Dungeons and Dragons with college students and other adults. Bob tells me that I should have saved my collection of these games -- that they'd be very valuable today! Actually, the design of games and rule systems interested me even more than play.

Although I admire the elegance of classical games like Chess and Go, I prefer simulation games. More specifically, I enjoy thinking about the design and structure of these games. A good analogy is the distinction between natural science and mathematics. The former attempts to distill truths about the workings (dynamics) of the natural world, whereas the latter can be admired solely for its abstract beauty and elegance. To me Chess sometimes feels too finite and crystalline. The challenge of formulating a system of rules that captures the key strategic or tactical issues facing, e.g., Stalin, or an infantry platoon, or the ruler of a city state, or even a science postdoc, is just messy enough to be more interesting to me than the study of a finite abstract system. To some extent, every theoretical scientist, economist and financial modeler is participating in a kind of game design -- building a simplified model without throwing away the essential details.

I think role playing games are overly maligned, even among the community of gamers. Under ideal circumstances, role playing games are highly educational, and combine components like story telling, negotiation, diplomacy and team building. At the club I attended one of the "game masters" (I know, it sounds silly!) was a portly older man named Bill Dawkins, who preferred to be called Standing Bear (his Native American name). Standing Bear, though possessed of limited formal education, was widely read and had lived a vast life. He was the most creative story teller and world creator I have known. His ideas were easily as original and interesting as those I had encountered in science fiction and fantasy writing. Each of the role playing campaigns he created, taking place over years, was a masterpiece of imagination and myth building. He attracted scores of players from around the region. I often found myself playing alongside or against people I barely knew, although some came to be close friends.

Netbooks and the twilight of wintel dominance?

A nice piece in today's Times on the popularity of netbooks and the threat posed to the Windows-Intel alliance by Linux combined with inexpensive CPUs designed by ARM and other smaller chip companies. The latter are currently used in cellphones, but have enough power to provide basic PC functionality. I've played with a couple of netbooks and really like them. Rumor has it that a Mac netbook is already in the works.

NYTimes: ...The new breed of netbooks, built on cellphone innards, threatens to disrupt that oligopoly.

Based on an architecture called ARM, from ARM Holdings in Britain, cellphone chips consume far less power than Atom chips, and they combine many functions onto a single piece of silicon. At around $20, they cost computer makers less than an Atom chip with its associated components.

But the ARM chips come with a severe trade-off — they cannot run the major versions of Windows or its popular complementary software.

Netbook makers have turned to Linux, an open-source operating system that costs $3 instead of the $25 that Microsoft typically charges for Windows XP. They are also exploring the possibility of using the Android operating system from Google, originally designed for cellphones. (Companies like Acer, Dell and Hewlett-Packard already sell some Atom-based netbooks with Linux.)The cellphone-chip makers argue that the ARM-Linux combination is just fine for a computer meant to handle e-mail, Facebook, streaming video from sites like YouTube and Hulu, and Web-based documents.

Freescale, for example, gave free netbooks to a group of 14- to 20-year-olds and watched what happened. “They would use it for Internet access when eating breakfast or on the couch, or bring it to class for taking notes,” said Glen Burchers, the director of consumer products marketing at Freescale.

Mr. Burchers said a number of companies already making netbooks would show a new round of machines using cellphone chips at the Computex trade show in Taipei, Taiwan, this June.

The future of innovation

A reader sent me this article from PhysicsWorld, which considers the nature of scientific innovation. I particularly agree with Smolin's comments excerpted below. The reward structure of academic science encourages narrow specialization far too much. Tremendous lip service is paid to interdisciplinary work, but in actuality it is very risky to undertake.

Using Smolin's analogy of hill climbing, the dominant strategy today in science is:

1) self-assess own climbing ability
2) choose suitable hill (perhaps inherited from advisor!)
3) climb to local maximum (write some relevant papers with incremental results)
4) squat on hilltop and defend against all attackers (make sure everyone cites your papers; get embedded in small community of researchers defending that hill)
5) train students and postdocs on your hilltop while secretly wishing you understood what other people were doing on their hilltops -- suppressing the curiosity that originally got you into science.

From personal experience, I can tell you that when you leave your little hill to cross a valley and explore somewhere else, the citations of your previous work will plummet, inhabitants of other hills will try to repel you, and funding agencies will ask why you aren't doing mainstream stuff ("he's not serious -- he keeps jumping around"). Based on this incentive system, it is easy to understand why people behave as they do.

...returns on research investment do not arrive steadily and predictably, but erratically and unpredictably, in a manner akin to intellectual earthquakes. Indeed, this idea seems to be more than merely qualitative. Data on human innovation, whether in basic science or technology or business, show that developments emerge from an erratic process with wild unpredictability. For example, as physicist Didier Sornette of the ETH in Zurich and colleagues showed a few years ago, the statistics describing the gross revenues of Hollywood movies over the past 20 years does not follow normal statistics but a power-law curve — closely resembling the famous Gutenberg— Richter law for earthquakes — with a long tail for high-revenue films. A similar pattern describes the financial returns on new drugs produced by the bio-tech industry, on royalties on patents granted to universities, or stock-market returns from hi-tech start-ups.

What we know of processes with power-law dynamics is that the largest events are hugely disproportionate in their consequences. In the metaphor of Nassim Nicholas Taleb’s 2007 best seller The Black Swan, it is not the normal events, the mundane and expected “white swans” that matter the most, but the outliers, the completely unexpected “black swans”. In the context of history, think 11 September 2001 or the invention of the Web. Similarly, scientific history seems to pivot on the rare seismic shifts that no-one predicts or even has a chance of predicting, and on those utterly profound discoveries that transform worlds. They do not flow out of what the philosopher of science Thomas Kuhn called “normal science” — the paradigm-supporting and largely mechanical working out of established ideas — but from “revolutionary”, disruptive and risky science.

Squeezing life out of innovation

All of which, as Sornette has been arguing for several years, has important implications for how we think about and judge research investments. If the path to discovery is full of surprises, and if most of the gains come in just a handful of rare but exceptional events, then even judging whether a research programme is well conceived is deeply problematic. “Almost any attempt to assess research impact over a finite time”, says Sornette, “will include only a few major discoveries and hence be highly unreliable, even if there is a true long-term positive trend.”

This raises an important question: does today’s scientific culture respect this reality? Are we doing our best to let the most important and most disruptive discoveries emerge? Or are we becoming too conservative and constrained by social pressure and the demands of rapid and easily measured returns? The latter possibility, it seems, is of growing concern to many scientists, who suggest that modern science is in danger of losing its creativity unless we can find a systematic way to build a more risk-embracing culture.

The voices making this argument vary widely. For example, the physicist Geoffrey West, who is currently president of the Santa Fe Institute (SFI) in New Mexico, US, points out that in the years following the Second World War, US industry created a steady stream of paradigm-changing innovations, including the transistor and the laser, and it happened because places such as Bell Labs fostered a culture of enormously free innovation. “They brought together serious scientists — physicists, engineers and mathematicians — from across disciplines”, says West, “and created a culture of free thinking without which it’s hard to imagine how these ideas could have come about.”

Unfortunately, today’s academic and corporate cultures seem to be moving in the opposite direction, with practices that stifle risk-taking mavericks who have a broad view of science. At universities and funding agencies, for example, tenure and grant committees take decisions based on narrow criteria (focusing on publication lists, citations and impact factors) or on specific plans for near-term results, all of which inherently favour those working in established fields with well-accepted paradigms. In recent years, tightening business practices and efforts to improve efficiency have also driven corporations in a similar direction. “That may be fine in the accounting department,” says West, “but it’s squeezing the life out of innovation.”

...But physicist Lee Smolin, currently at the Perimeter Institute, suggests that science overall requires a much broader and more coherent approach to risky science. To see the kinds of policies needed, he suggests, it is useful to note that scientists, at least in some rough approximation, follow working styles of two very different kinds, which mirror Kuhn’s distinction between normal and revolutionary science.

Some scientists, he suggests, are what we might call “hill climbers”. They tend to be highly skilled in technical terms and their work mostly takes established lines of insight that pushes them further; they climb upward into the hills in some abstract space of scientific fitness, always taking small steps to improve the agreement of theory and observation. These scientists do “normal” science. In contrast, other scientists are more radical and adventurous in spirit, and they can be seen as “valley crossers”. They may be less skilled technically, but they tend to have strong scientific intuition — the ability to spot hidden assumptions and to look at familiar topics in totally new ways.

To be most effective, Smolin argues, science needs a mix of hill climbers and valley crossers. Too many hill climbers doing normal science, and you end up sooner or later with lots of them stuck on the tops of local hills, each defending their own territory. Science then suffers from a lack of enough valley crossers able to strike out from those intellectually tidy positions to explore further away and find higher peaks.