Age is of course a fever chill?: Why even older scientists can make important contributions

A ditty often attributed to Paul Dirac conveys the following warning about doing scientific work in your later years:

Age is of course a fever chill
That every physicist must fear
He is better dead than living still
When past his thirtieth year

Dirac was of course a member of the extraordinary generation of physicists who changed our understanding of the physical world through the development of quantum mechanics in the 1920s and 30s. These men were all in their 20s when they made their revolutionary discoveries, with one glaring exception - Erwin Schrodinger was, by the standards of theoretical physics, a ripe old thirty-eight when he stumbled across the famous equation bearing his name.

When we look at the careers of these individuals we could be forgiven for assuming that if you are past thirty you will probably not make an important contribution to science. The legend of the Young Turks has not quite played out in other fields of science though. Now a paper in PNAS confirms what we suspected, that since the turn of the twentieth century there has been a general increase in the age at which scientists make their important discoveries. What is more surprising is that this increase exists more across time than across fields. The study looks at Nobel Laureates, but since many people who make Nobel Prize worthy discoveries never get the prize, the analysis applies to others too.

So what does the paper find out? It finds out that in the early years of the last century, young men and women made contributions in every field at a relatively young age, often in their twenties. This was most pronounced for theoretical physics. Einstein famously formulated special relativity when he was a 26-year-old patent clerk, and Heisenberg formulated quantum mechanics when he was 24. The same was true for many other physicists including Bohr, Pauli, Dirac and De Broglie and the trend continued into the 70s, although it was less true for chemists and biologists studied by the authors.

The reasons postulated in the paper are probably not too surprising but they illustrate the changing nature of scientific research during the last one hundred years or so. It is easiest for a brilliant individual to make an early contribution to a theoretical field like theoretical physics or mathematics, since achievement in such fields depends more on raw, innate ability than skills gained over time. In an experimental field it's much harder to make early contributions since one needs time to assimilate the large body of experimental work done and to learn the painstaking trade of the experimentalist, an endeavor where patience and perseverance count much more than innate intelligence. As the paper puts it, deductive knowledge lends itself more easily to innate analytical thinking skills visible at a young age than inductive knowledge based on a large body of existing work. This is true even for theoretical physicists where fundamental discoveries have become extremely hard and scarce, and where new ideas depend as much on integrating an extensive set of facts into your thinking process as on "Eureka!" moments. And this difference holds even more starkly for social sciences like economics and psychology where you find very few young people making Nobel Prize winning contributions. In these cases success depends as much on intellectual maturity gained from a thorough assimilation of data about extremely complex systems ("humans") as it does on precocity.

But if this were purely the distinction, then we wouldn't find young people making contributions even to experimental chemistry and biology in the early twentieth century. The reason why this happened is also clear; there was a lot of low-hanging fruit to be picked. So little was known for instance about the molecular components of living organisms that almost every newly discovered vitamin, protein, alkaloid, carbohydrate or steroid could bag its discoverer a Nobel prize. The mean age for achievement was not as early as in theoretical physics, but the contrast is still clear. Even in theoretical physics, the playing field was so rife for new discoveries in the 1930s that in Dirac's words, "even a second-rate physicist could make a first-rate discovery". The paper draws the unsurprising conclusion that there is much more opportunity for a young person to discover something new in a field where little is known.

This conclusion is starkly illustrated in the case of DNA. Watson and Crick are the "original" Young Turks. Watson was only 25 and Crick was in his early thirties when they cracked open the DNA structure, although one has to give Crick a pass since his career was interrupted by the war. What's important to note is that both Watson and Crick came swinging into the field with very little prior knowledge. For instance they both knew very little chemistry. But in this case this lack of knowledge did not really hold them back and in fact freed up their imagination because they were working in a field where there were no experts, where even newcomers could use the right kind of knowledge (crystallography and model building in this case) to make important discoveries. Watson and Crick's story points to a tantalizing thought- that it may yet be possible to make fundamental contributions at a young age to fields in which virgin territory is still widely available. Neuroscience comes to mind right away.

Since this is a chemistry blog, let's look at the authors' conclusions as they apply to chemistry. Linus Pauling provides a very interesting example since he plays into both categories. The "early Pauling" made his famous contributions to chemical bonding in his twenties, and this contribution was definitely more of the deductive kind where you could indulge in much armchair analysis based on principles and approximations drawn from quantum theory. In contrast, contributions by the "late Pauling" are much more inductive. These would include his landmark discovery of the fundamental elements of protein structure (the alpha helix and the beta sheet) and the first description of a disease at a molecular level (sickle cell anemia). Pauling did both these things in his 40s, and both of them needed him to build up from an extensive body of knowledge about crystallography, chemical bonding and biochemistry. It would be hard to imagine even a Linus Pauling deducing protein structure the way he deduced orbital hybridization.

If we move to more inductive fields then the relatively advanced age of the participants is even more obvious. In fact in chemistry, in contrast to mathematics or physics, it's much harder to pinpoint a young revolutionary precisely because chemistry more than physics is an experimental science based on the accumulation of facts. Thus even exceptional chemists are often singled out more for lifelong contributions than for lone flashes of inspiration. Even someone as brilliant as R. B. Woodward (who did make his mark at a young age) was really known for his career-wide contributions to organic synthesis rather than any early idea. It's also interesting that Woodward did make a very important contribution in his late 40s - to the elucidation of the Woodward-Hoffmann rules- and although Hoffmann provided a robust deductive component, inspiration for the rules came to Woodward through anomalies in his synthesis of Vitamin B12 and his vast knowledge of experimental data on pericyclic reactions. Woodward was definitely building up from a lot of inductive knowledge.

An additional factor that the authors don't discuss is the contribution of collaborations. From a general standpoint it has now become very difficult for scientists in any field to make lone significant contributions. In fact one can make a good case that even the widely cited lone contributions to theoretical physics in the 1920s involved constant collaboration and exchange of ideas (mostly through Niels Bohr's institute in Copenhagen). This was far from the case for most of scientific history, when you had people like Cavendish, Lavoisier, Maxwell, Faraday, Kekule and Planck working alone and producing spectacular results. But things have significantly changed, especially in the case of experimental particle physics and genomics where even the most outstanding thinkers can often work only as part of a team. In such cases it may even be meaningless to talk about the young vs advanced age dichotomy since no one individual makes the most important discovery.

Finally, one rather disturbing reason that could potentially contribute to an even greater advancement of age in the context of important discoveries is left undiscussed. As the biologist Bob Weinberg lamented in an editorial a few years ago, the mean age at which new academic researchers receive their first important research grant has been advancing. This means that even brilliant scientists may be held back from making important discoveries simply because they lack the resources. While this trend has really been visible in the last decade or so, it could contribute as an unfortunate factor to the age-corrected generation of novel ideas. One only hopes that this does not make things so bad that scientists are forced to consider contributing to their fields in their 70s.

Ultimately there's one thing that age brings that's hard to replace with raw brilliance, and that's the nebulous but invaluable entity called 'intuition'. As scientific problems become more and more complex and interdisciplinary, it is inevitable that intuition and experience will play more important roles in the divining of new scientific phenomena. And these are definitely a product of age, so there may be something to look forward to when you grow old after all.

The future of science: Will models usurp theories?

This year's Nobel Prize for physics was awarded to Saul Perlmutter, Brian Schmidt and Adam Riess for their discovery of an accelerating universe, a finding leading to the startling postulate that 75% of our universe contains a hitherto unknown entity called dark energy. All three were considered favorite candidates for a long time so this is not surprising at all. The prize also underscores the continuing importance of cosmology since it had been awarded in 2o06 to George Smoot and John Mather, again for confirming the Big Bang and the universe's expansion.

This is an important discovery which stands on the shoulders of august minds and an exciting history. It continues a grand narrative that starts from Henrietta Swan Leavitt (who established a standard reference for calculating astronomical distances) through Albert Einstein (whose despised cosmological constant was resurrected by these findings) and Edwin Hubble, continuing through George Lemaitre and George Gamow (with their ideas about the Big Bang) and finally culminating in our current sophisticated understanding of the expanding universe. Anyone who wants to know more about the personalities and developments leading to today's event should read Richard Panek's excellent book "The 4 Percent Universe".

But what is equally interesting is the ignorance that the prizewinning discovery reveals. The prize was really awarded for the observation of an accelerating universe, not the explanation. Nobody really knows why the universe is accelerating. The current explanation for the acceleration consists of a set of different models, none of which has been definitively proven to explain the facts well enough. And this makes me wonder if such a proliferation of models without accompanying concrete theories is going to embody science in the future.

The twentieth century saw theoretical advances in physics that agreed with experiment to an astonishing degree of accuracy. The culmination of achievement in modern physics was surely quantum electrodynamics (QED) which is supposed to be the most accurate theory of physics we have. Since then we have had some successes in quantitatively correlating theory to experiment, most notably in the work on validating the Big Bang and the development of the standard model of particle physics. But dark energy- there's no theory for it that remotely approaches the rigor of QED when it comes to comparison with experiment.

Of course it's unfair to criticize dark energy since we are just getting started on tackling its mysteries. Maybe someday a comprehensive theory will be found, but given the complexity of what we are trying to achieve (essentially explain the nature of all the matter and energy in the universe) it seems likely that we may always be stuck with models, not actual theories. And this may be the case not just with cosmology but with other sciences. The fact is that the kinds of phenomena that science has been dealing with recently have been multifactorial, complex and emergent. The kind of mechanical, reductionist approaches that worked so well for atomic physics and molecular biology may turn out to be too impoverished for taking apart these phenomena. Take biology for instance. Do you think we could have a complete "theory" for the human brain that can quantitatively calculate all brain states leading to consciousness and our reaction to the external world? How about trying to build a "theory" for signal transduction that would allow us to not just predict but truly understand (in a holistic way) all the interactions with drugs and biomolecules that living organisms undergo? And then there's other complex phenomena like the economy, the weather and social networks. It seems wise to say that we don't anticipate real overarching theories for these phenomena anytime soon.

On the other hand, I think it's a sign of things to come that most of these fields are rife with explanatory models of varying accuracy and validity. Most importantly, modeling and simulation are starting to be considered as a respectable "third leg" of science, in addition to theory and experiment. One simple reason for this is the recognition that many of science's greatest current challenges may not be amenable to quantitative theorizing, and we may have to treat models of phenomena as independent, authoritative explanatory entities in their own right. We are already seeing this happen in chemistry, biology, climate science and social science, and I have been told that even cosmologists are now extensively relying on computational models of the universe. Admittedly these models are still far behind theory and experiment which have had head starts of about a thousand years. But there can be little doubt that such models can only become more accurate with increasing computational firepower. How accurate remains to be seen, but it's worth noting that there are already books that make a case for an independent, study-worthy philosophy of modeling and simulation. These books extol philosophers of science to treat models not just as convenient applications and representations of theories (which are then the only fundamental things worth studying) but as ultimate independent explanatory devices in themselves that deserve separate philosophical consideration.

Could this then be at least part of the future of science? A future where robust experimental observations are encompassed not by beautifully rigorous and complete theories like general relativity or QED but only by different models which are patched together through a combination of rigor, empirical data, fudge factors and plain old intuition? This would be a new kind of science, as useful in its applications as its old counterpart but rooting itself only in models and not in complete theories. Given the history of theoretical science, such a future may seem dark and depressing. That is because as the statistician George Box famously quipped, although some models are useful, all models are wrong. What Box meant was that models often feature unrealistic assumptions about all kinds of details that nonetheless allow us to reproduce the essential features of reality. Thus they can never provide the sure connection to "reality" that theories seem to. This is especially a problem when disparate models give the same answer to a question. In the absence of discriminating ideas, which model is then the "correct" one? The usual answer is "none of them", since they all do an equally good job of explaining the facts. But this view of science, where models that can be judged only on the basis of their utility are the ultimate arbiters of reality and where there is thus no sense of a unified theoretical framework, feels deeply unsettling. In this universe the "real" theory will always remain hidden behind a facade of models, much as reality is always hidden behind the event horizon of a black hole. Such a universe can hardly warm the cockles of the heart of those who are used to crafting grand narratives for life and the universe. However it may be the price we pay for more comprehensive understanding. In the future, Nobel Prizes may be frequently awarded for important observations for which there are no real theories, only models. The discovery of dark matter and energy and our current attempts to understand the brain and signal transduction could well be the harbingers of this new kind of science.

Should we worry about such a world rife with models and devoid of theories? Not necessarily. If there's one thing about science that we know, it's that it evolves. Grand explanatory theories have traditionally been supposed to be a key part- probably the key part- of the scientific enterprise. But this is mostly because of historical precedent as well a psychological urge for seeking elegance and unification. Such belief has been resoundingly validated in the past but it's utility may well have plateaued. I am not advocating some "end of science" scenario here - far from it - but as the recent history of string theory and theoretical physics in general demonstrates, even the most mathematically elegant and psychologically pleasing theories may have scant connection to reality. Because of the sheer scale and complexity of what we are trying to currently explain, we may have hit a roadblock in the application of the largely reductionist traditional scientific thinking which has served us so well for half a millennium

Ultimately what matters though is whether our constructs- theories, models, rules of thumb or heuristic pattern recognition- are up to the task of constructing consistent explanations of complex phenomena. The business of science is explanation, whether through unified narratives or piecemeal explanation is secondary. Although the former sounds more psychologically satisfying, science does not really care about stoking our egos. What is out there exists, and we do whatever's necessary and sufficient to unravel it.

Putting the filosophy back into fysiks

How the Hippies Saved Physics: Science, Counterculture, and the Quantum Revival- David Kaiser

Does philosophy have a place in serious science? Many of the founders of modern physics certainly thought so. Einstein, Bohr, Heisenberg and Schrodinger were not just great scientists but they were equally enthusiastic and adept at pondering the philosophical implications of quantum theory. To some extent they were forced to confront such philosophical questions because the world that they were discovering was just so bizarre and otherworldly; particles could be waves and vice versa, cats (at least in principle) could be alive and dead, particles that were separated even by light years appeared to be able to communicate instantaneously with each other, and our knowledge of the subatomic world turned out to be fundamentally probabilistic.

However, as quantum theory matured into a powerful tool for calculation and concrete application, the new generation of physicists in general and American physicists in particular started worrying less about "what it means" and much more about "how to use it". American physicists had always been more pragmatic than their European counterparts and after World War 2, as the center of physics moved from Europe to the United States and as the Cold War necessitated a great application of science to defense, physicists turned completely from the philosophizing type to what was called the "shut up and calculate" kind; as long as quantum mechanics agrees spectacularly with experiment, why worry about what it means? Just learn how to use it. Yet this only swept epistemological questions under the rug.

Curiously, there emerged in the 1970s a quirky and small group of physicists in the Bay Area who tried to resurrect the age of philosopher-scientists. In "How the Hippies Saved Physics", David Kaiser wonderfully tells the very engaging story of this "Fundamental Fysiks" group and how it kept alive some of the deep philosophical questions that had haunted the founding fathers. The "Fysicists" came from a variety of backgrounds, but all of them had been dissatisfied; both by the dismal job market for physicists after the Cold War craze and more importantly by the purely practical approach toward physics which they learnt in graduate school. Interestingly they combined their deep questions about physics with the emerging hippie counterculture of the 60s and 70s and it's pretty clear from the book that they had great fun doing this; after all this was an age when non-conformity was encouraged. Discussions of physics concepts blended seamlessly with Eastern mysticism, forays into LSD-induced mind experiments, New Age workshops at the Esalen Institute in California and meanderings into telepathy, consciousness and parapsychology. Books like Fritjof Capra's "The Tao of Physics" which explored parallels between modern physics and Eastern religions only helped the movement. The small group of physicists was also fortunate to get funding from some unlikely sources, including self-help guru Werner Erhard and even the CIA who was interested in possible connections between ESP and physics. Not surprisingly, mainstream physicists often ignored and sometimes actively condemned such activities

However, as Kaiser describes in this fascinating volume, this ragtag group of countercultural philosopher-scientists achieved at least one crucial goal; they kept questions about the philosophical implications of quantum theory alive at a time when most physicists eschewed and disdained such questions. Gradually, they managed to get a handful of mainstream physicists interested in their philosophizing. Much of the connection of this philosophy to real physics centered about a remarkable result called Bell's theorem which essentially reinforced the spooky properties of quantum systems by showing that information in quantum systems can flow instantaneously between particles. Remarkably, this seemingly otherworldly idea of "quantum entanglement" (which gave some of the founding fathers heartburn) now lies at the foundation of some of the most cutting-edge areas of modern physics, including quantum computation and the new discipline of quantum information science. What was considered far-flung by mainstream physicists and kept alive by the Fundamental Fysiks group is now serious physics for many. In fact, at least a few physicists who put Bell's theorem to experimental test are regarded as candidates for a Nobel Prize (these especially include John Clauser, Alain Aspect and Anton Zeilinger who shared the prestigious Wolf Prize- often a forerunner to the Nobel Prize- in 2010).

In the end Kaiser wants to make the case that by keeping such once-disparaged philosophical concepts alive, the Fundamental Fysicists "saved physics". I am a little skeptical of this claim. They certainly managed to nurture and publicize the concepts, but it was the harnessing of these concepts by "real" physicists who were involved with the nuts and bolts of calculation and experiment that actually saved the concepts and kept them from turning into a purely philosophical mishmash. In addition, a lot of concepts that the New Age physicists bandied about belonged squarely in the realm of pseudoscience and the trend continues; people like Deepak Chopra commit gross violations of quantum mechanics on a daily basis. Unfortunately the line between science and non-science can be thin and one of the most intriguing discussions in Kaiser's book is this so-called "demarcation problem". How does one know if today's philosophy is tomorrow's cutting edge science or just noisy mumbo-jumbo? It's not always easy to say.

Nonetheless, I think Kaiser and the Fysicists make a really great general case for why philosophical questions in science have their own place and should not be rejected. For one thing, they are always fascinating in themselves and demonstrate the endless human quest for meaning and reality; as recent discussions indicate, the philosophical conundrums in physics have been far from answered and continue to be explored through even more bizarre ideas like parallel universes and multiple dimensions. And as this wonderful book shows, at least in some cases these discussions may lead to key advances by influencing mainstream physicists who validate them by subjecting them to the ultimate arbiter of truth in science- hard experiment.

One more thing we can learn from Linus Pauling

What makes a successful scientist? The question is hard to answer, not because there is no general consensus but because the precise contribution of specific factors in individual cases cannot always be teased out. Intelligence is certainly an important feature but it can manifest itself in myriad ways. Apart from this, having a good nose for important problems is key. Perhaps most important is the ability to persevere in the face of constant frustration and discouragement. And then there is luck, that haphazard driving force whose blessings are unpredictable but can be discerned by Alexander Fleming's famous "prepared minds".

But aside from these determinants, one factor stands out which may not always be obvious because of it's negative connotation; and that is the good sense to realize one's weaknesses and the willingness to give up and marshal one's resources into a more productive endeavor. Admitting one's weaknesses is understandably an unpleasant task; nobody wants to admit what they are not good at, especially if they have worked at it for years. That kind of attitude does not get you job offers or impress interviewers. Yet being able to admit what qualities you lack can make your life take a radically successful direction. And lest we think that only mere mortals have to go through this painful process of periodic self-evaluation and subsequent betterment, we can be rest assured. It was none other than Linus Pauling who went through this soul-searching. And we are all the wiser for his decision.

When Pauling graduated from Oregon State University in 1922, he had already shown great promise. At that point he had had an excellent overall education in mathematics and physics and compared to his peers in the United States was mathematically quite outstanding. In 1926 he won a Guggenheim fellowship to study in Europe under the tutelage of Arnold Sommerfeld in Munich, with trips to the great centers of physics in Copenhagen, Gottingen and Zurich included as part of the package. There Pauling met the founders of quantum mechanics, almost all of whom were about the same age, and realized that maybe his talents in physics and mathematics were not as great as he thought. There is a story, probably apocryphal, that the famously acerbic Pauli dismissed one of his papers on quantum mechanics with two short words- "Not interesting".

At this point Pauling made what was one of the the wisest decisions of his life; he decided to focus not on physics but on chemistry. He swallowed his frustration at being beaten by the best and brightest of his generation in physics and realized the great value of striking out into new territory. Why? Because his mathematical and analytical abilities, while being of considerable value in physics, would be of wholly unique import in chemistry. At that point and to some extent even today, gifted mathematicians and quantitative thinkers are quite common in physics but less so in chemistry and biology. That is precisely what makes them more valuable in the latter disciplines. In addition, Pauling had always had an empirical and experimental bent, demonstrated by his earlier research in crystallography. So chemistry it was, and the rest is history. Pauling ended up making contributions to chemistry whose significance easily paralleled that of contributions made by Heisenberg, Pauli, Dirac and Schrodinger to physics.

There are two key lessons to be drawn from Pauling's story. The first lesson is to know when to let go, to know what path on the famed fork not to take. History would likely have been quite different if Pauling had decided to be stubborn and spent the rest of his career trying to outcompete his fellow theoretical physicists. But the bigger lesson is extremely valuable for scientists wanting to make discoveries. Take a skill-set which is valuable but not groundbreaking in one discipline, and then apply it to another discipline where it will lead to novel insights and real breakthroughs. Or to put in another way, move from a crowded field where you may share your particular talent with dozens of others to one which is sparser and where your talent will be more unique, productive and appreciated. The other related lesson is to capitalize on pairs of skills, each of which by itself may not be unique but whose combination turns out to be explosive in a particular field. For instance Pauling combined his deep grounding in physics with an encyclopedic memory and a remarkably wide knowledge of chemistry's empirical facts. There were a few chemists who could marshal one or the other talent, but almost nobody could serve up Pauling's powerful one-two punch. One can find similar analogies in combinations of diverse skills like computer science and molecular biology, or electrical engineering and neuroscience.

The history of science abounds with success stories stemming from this kind of recipe. Physicists venturing into biology constitute the best example. Francis Crick was a good physicist, but he probably would not have become a great one had he stayed in physics. Instead Crick had the wisdom to realize the value of applying his physicist's mind to problems in biology and became one of the greatest biologists of the century. Walter Gilbert trained under the theoretical physics virtuoso Julian Schwinger and would have been a first-rate physicist, but applying his talents to biology enabled him to become one of the founders of molecular biology. There are also more exotic examples. The quantum physicist Tjalling Koopmans who fathered a well-known theorem in quantum chemistry did so well in econometrics that he won a Nobel Prize. In fact just like biology, economics has been another field which has been thoroughly enriched by thinkers who would have been good mathematicians or physicists but who became great economists (although the application of strict mathematical modeling in economics can lead to a world of pain). There are more local and specialized examples too. A professor of mine who is world-renowned in the physical organic chemistry of surfactants and lipids told me that he considered working in protein chemistry but realized that the field was too crowded; lipids, on the other hand, were under-explored and could benefit from exactly the kind of talents he has.

This is precisely the reason why biology is such a fertile playing field for outsiders of all stripes, from biologists and computer scientists to engineers. The kind of complex systems that biology deals with can only be unraveled through a variety of talents which people from diverse disciplines bring to the table. On one hand you need reductionist, quantitative scientists to set biology on a rigorous theoretical basis but you also need 'higher-level' thinkers who can tie together threads from disparate empirical phenomena. That's why both mathematicians and doctors continue to make valuable contributions to the field. The same can be said of chemistry. Quantum chemists like Pauling did much to root chemistry in physics, yet the sheer complexity of chemistry (after all the Schrodinger equation can be solved exactly for no atom bigger than hydrogen) demands more intuitive thinkers who can devise approximations and include empirical parameters to improve chemical prediction. Similarly, organic chemists like Stuart Schreiber and Peter Schultz were excellent synthetic chemists, but it was in the application of synthetic chemistry to biology that they found unexplored terrain and great riches.

The lesson for young scientists seems to be clear. The most explosive discoveries can result from applying talents suitable for one field to a whole new different field. And perhaps this is not surprising. Nature is not hostage to the boundaries of disciplinary convenience devised by fallible human beings and does not divide itself into rigid compartments titled "Physics", "Biology", "Approximation" or "Analytical Solutions". Nature encompasses phenomena whose analysis spans a continuum. It is hardly surprising then that she yields her secrets best to those who are more than willing to use each and every tool of analysis to criss-cross her myriad domains.

Quo vadis, natural science?

On Wednesday last week the town where I lived got 20 inches of snow in a twenty-four hour period. I got an unexpected, happy, day off work. Bizarrely, southern regions like Washington and Baltimore got much more than northern ones; Baltimore got 40 inches, Philadelphia got about the same. Records were set in both places for the snowiest winters in recent history. People were left wondering and reeling at this capriciousness of the Norse Gods.

So what could be the reason for this sudden onslaught of severe weather? That’s akin to asking what could be the reason for cancer suddenly emerging in someone’s body or for a particular drug demonstrating a slew of side-effects. The reasons are non-obvious, often non-intuitive, complex, multifactorial and extremely hard to determine. And that is also what one should say if asked to elucidate reasons for a particularly snowy winter.

But human beings don’t work that way...


...Read the rest of the post on the Desipundit blog