How Do You Know a Nuclear Weapon Works If You Can’t Test It?

In the end, I keep coming back to the question of how you know a weapon works if you cannot test it. (Or, for that matter, how testing ever established reliability since it destroyed the object whose reliability it demonstrated.) Who am I to question the judgment of the physicists who have spent decades honing their expert knowledge of this arcane field? Still, I keep thinking of a conversation I had in 1995 with a senior weapons designer, now retired, who told me that an inexperienced designer with a code is like a drunk driver, wrongly convinced of their excellent judgment. And I cannot help but notice a 2012 Department of Energy report complaining that National Ignition Facility shots were not producing the energy levels predicted by simulation codes. Nor, in 2015, has the National Ignition Facility met its former director’s prediction of reaching ignition—getting more energy out than was put in—by late 2012.

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Hugh Gusterson — Institute for Advanced Studies

We Have to Go Beyond Identifying and Punishing Individual Men

If we are to seriously address the current crisis beyond identifying and punishing individual men as bad actors, we have to attend to this history and make apparent how deeply rooted it is in our culture and our psyches. Without that critical intervention—without attention to what might be called “the lessons of history”—the flurry of revelations about longstanding and long  tolerated exercises of men’s power, however horrifying in their details, will not suffice to achieve what is required to permanently change the gendered power dynamics of our culture.

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Joan Wallach Scott — IAS

Paul Dirac: The Mozart of Science


Happy New Year! A big thank you to all the visitors and magnets from Needull. We have our first needull for the year.

Dirac began his first yearlong sabbatical at the Institute in the fall of 1934, a stay that later stood out as one of the most memorable times of his life. Working alone as usual, he intended to use his new approach of growing fundamental physical theories from purely mathematical seeds. But the year was dominated by two diversions. First, his closest friend, the Russian experimenter Peter Kapitza, was detained against his will by Stalin’s police during a summer visit when on vacation from Cambridge. As soon as Dirac heard about this, he spent months trying to get his friend released, on one occasion lobbying the Soviet Ambassador in Washington. Dirac’s second distraction began over lunch on Nassau Street when the Hungarian theoretician Eugene Wigner introduced him to his sister, who would later become Dirac’s wife, Manci Balazs. The Diracs were in many ways opposites—he was shy, modest, taciturn, and he often appeared cold and distant; she was outgoing, confident, talkative, a warm and considerate friend. It was an unlikely relationship, but their marriage worked and was ended only by his death almost half a century later.

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Graham Farmelo — IAS

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My Search for Ramanujan


Another needull on Ramanujan. Ramanujan is an Indian mathematician who continues to fascinate me endlessly.

Using a long and complicated argument, we finally found a way to show that the truth of the generalized Riemann hypothesis implies that every odd number greater than 2719 can be written as x2 + y2 + 10z2 for some integers xy, and z. The fact that almost every mathematician believes in the truth of the generalized Riemann hypothesis and the fact that every odd number greater than 2719 up to a very large number can be represented by Ramanujan’s quadratic form convinced us that we had found the law. But although the law is simple enough to state, it thus far defies a definitive proof. To be sure, if someone manages to prove the generalized Riemann hypothesis, then our conditional proof will at once become a genuine proof. But the generalized Riemann hypothesis is arguably one of the most difficult open problems in mathematics. So Ramanujan was right that the odd numbers do not obey a simple law, in the sense that they are constrained by one of the most difficult unsolved problems in mathematics.

I had no idea that I would see the number 2719 again ten years later, etched on a wall in the very spot where Ramanujan performed some of his first calculations.

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Ken Ono — IAS

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The Professor and the Politician


This needull is just an anecdote. But, it points out a serious malady in today’s academia and the reason for mediocrity.

“But that is exactly what we would like to achieve in our Effectivity Committee. Scientists should not think about problems that are too difficult, but rather focus on problems that will increase the number of publications. Then our numeric criteria can be applied to evaluate your work in a simple way, which will allow us to confirm the quality of your work immediately.”

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Nils A. Baas — IAS

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