Field of Science

JFK, nuclear weapons and the 1963 'Peace Speech': Looking back sixty five years

Sixty five years ago, on June 10, 1963, President John F. Kennedy made an impassioned plea for peace to the world on the campus of American University in Washington D.C. The speech was carefully crafted, copies were shown to only a few trusted advisors for comment, and Kennedy's ace speechwriter Ted Sorensen worked on it day and night to meet the president's schedule. In his book "To Move the World: JFK's Quest for Peace”, the economist Jeffrey Sachs considers this to be Kennedy's most important speech; JFK delivered many inspiring speeches – including the famous moon speech at Rice University (“We choose to go to moon not because it’s easy, but because it’s hard”) – but I tend to agree with Sachs that among all of them, no other speech has the sense of urgency and the long term relevance of the peace speech.

JFK's dedication to peacemaking shines through in his words. The piece contains one of the most memorable paragraphs that I have seen in any presidential speech. In words that are now famous, Kennedy appealed to our basic connection on this planet as the most powerful argument for worldwide peace:

"So let us not be blind to our differences, but let us also direct attention to our common interests and the means by which those differences can be resolved. And if we cannot end now our differences, at least we can help make the world safe for diversity. For in the final analysis, our most basic common link is that we all inhabit this small planet. We all breathe the same air. We all cherish our children's futures. And we are all mortal."

Kennedy was saying these words through hard experience, against the background of the Cuban Missile Crisis in October 1962 that had brought the world to the edge of nuclear war. Recently declassified documents now indicate that the Soviets had more than 150 nuclear weapons in Cuba, and there were many close calls which could have sent the world over the precipice. For instance, a little known submarine officer Vasili Arkhipov refused to launch his submarine's nuclear torpedo even as American planes were dropping dummy depth charges around the submarine. Contrary to what the self-serving accounts of Bobby Kennedy, McGeorge Bundy and other Kennedy advisors would later indicate, it was JFK himself who played the most pivotal role in keeping the crisis from escalating. When world war was averted, everyone thought that it was because of rational men's rational actions, but Kennedy knew better; he and his advisors understood how ultimately, helped as they were by their stubborn refusal to give in to military hardliners' insistence that Cuba should be bombed, it was dumb luck that saved humanity. Even later, George Lee Butler who headed the US Strategic Command during the end game of the Cold War said, “We escaped the Cold War without a nuclear holocaust by some combination of skill, luck, and divine intervention, and I suspect the latter in greatest proportion.”

Kennedy was thus well aware in 1963 of how quickly and unpredictably war in general and nuclear war in particular can spiral out of everyone's hands; two years before, in another well-known speech in front of the United Nations, Kennedy had talked about the ominous and omnipresent sword of Damocles that everyone lives under, "hanging by the slenderest of threads, capable of being cut at any moment by accident, or miscalculation, or by madness". His Soviet counterpart Nikita Khrushchev understood this too, cautioning JFK to not tighten the "knot of war" which would eventually have to be catastrophically severed. As one consequence of the crisis, a telephone hotline was established between the two countries that would allow their leaders to efficiently communicate with each other.

Kennedy followed the Peace Speech with one of the signal achievements of his presidency, the signing and ratification of the Partial Test Ban Treaty (PTBT) which banned nuclear tests in the air, underwater and in space. This treaty not allowed prevented untold amounts of radioactive fallout from contaminating the planet, but also made it much harder for other countries to develop nuclear weapons. The effort was far from straightforward; Sachs describes how Kennedy used all the powers of persuasion at his disposal to convince the Joint Chiefs of Staff, Republican hardliners and Southern Democrats to endorse the treaty, while at the same time striking compromises with them that would allow underground nuclear testing.
How have Kennedy's understanding of the dangers of nuclear war, his commitment to securing peace and his efforts toward nuclear disarmament played out in the fifty years after his tragic and untimely death? On one hand there is much cause for optimism. Kennedy's pessimistic prediction that in 1975 ten or twenty countries would have nuclear weapons has not come true. In fact the PTBT was followed in 1968 by the Nuclear Non-Proliferation Treaty, which for all its flaws has served as a deterrent to the formation of new nuclear states. Other treaties like SALT, START and most recently NEW START have drastically reduced the number of nuclear weapons to a fraction of what they were during the heyday of the Cold War; ironically it was Republican presidents Ronald Reagan and George H. W. Bush who must be credited with the greatest arms reductions. In addition, there are several success stories of countries like South Africa, Sweden, Libya, Brazil and the former Soviet Republics giving up nuclear weapons after wisely realizing that they would be better off without them.
Yet there are troubling signs that Kennedy's dream is still very much a dream. Countries like Israel and India which did not sign the NPT have acquired nuclear arsenals. North Korea is baring its nuclear teeth and Iran seems to be meandering even if not resolutely marching toward acquiring a bomb. In addition, loose nuclear material, non-state actors and unstable regimes like Pakistan pose an ever-present challenge that threatens to spiral out of control; the possibility of "accident, or miscalculation, or madness" is very much still with us.
There are also little signs that the United States is going to unilaterally disassemble its nuclear arsenal in spite of having the most sophisticated and powerful conventional weapons in the world, ones which can hit almost any target anywhere with massive destruction; this development was only made harder by the coming of the Trump administration which understands little about these weapons. In a recent piece in Physics Today, arms experts Richard Garwin, Frank von Hippel and Steve Fetter point out that the United States still possesses four thousand nuclear warheads, each one of which packs a punch that’s an order of magnitude bigger than the weapons which leveled Hiroshima and Nagasaki and many of which are designed to be launched within a 10 to 30 minute window of potential detection of enemy launches. As the author Eric Schlosser documented through stories of dozens of accidental almost-launched weapons, this narrow window leaves very little room for false alarms, malfunction or stupidity, each of which humanity possesses in spades. As the trio of physicists in Physics Today also notes, many in this country continue to be obsessed with missile defense; an obsession that goes back to the Reagan years and that time and time again has been shown to be largely unfeasible, both on technical as well as political grounds. Meanwhile, a comprehensive test ban treaty seems as out of reach as ever before.
There are some pinpricks of hope. The US did unilaterally disarm its biological and chemical weapons arsenal in the 70s – Richard Nixon did this virtually overnight, without asking anyone - but nuclear weapons still seem to inspire myths and illusions that cannot be easily dispelled. A factor that's not much discussed but which is definitely the massive elephant in the room is spending on nuclear weapons; depending on which source you are looking at, the US spends anywhere between 20 to 50 billion dollars every year on the maintenance of its nuclear arsenal, more than what it did during the Cold War. Thousands of weapons are still deployment-ready, years after the Cold War has ended. It goes without saying that this kind of spending is unconscionable, especially when it takes valuable resources away from pressing problems like healthcare and education. Eisenhower who warned us about the military-industrial complex lamented exactly this glut of misguided priorities in his own "Chance for Peace" speech in 1953:

"Every gun that is made, every warship launched, every rocket fired signifies, in the final sense, a theft from those who hunger and are not fed, those who are cold and are not clothed. This world in arms is not spending money alone. It is spending the sweat of its laborers, the genius of its scientists, the hopes of its children. The cost of one modern heavy bomber is this: a modern brick school in more than 30 cities. It is two electric power plants, each serving a town of 60,000 population. It is two fine, fully equipped hospitals. It is some fifty miles of concrete pavement. We pay for a single fighter with a half-million bushels of wheat. We pay for a single destroyer with new homes that could have housed more than 8,000 people. . . . This is not a way of life at all, in any true sense. Under the cloud of threatening war, it is humanity hanging from a cross of iron."
It is of course inconceivable to imagine a conservative politician saying this today, but more tragically it is disconcerting to find exactly the same problems that Eisenhower and Kennedy pointed out in the 50s and 60s looming over our future.
As Sachs discusses in his book, in a greater sense too Kennedy's vision is facing serious challenges. Sachs believes that sustainable development has replaced nuclear weapons as the cardinal problem facing us today and until now the signs for sustainable development have not been very promising. When it comes to states struggling with poverty, Sachs accurately reminds us that countries like the US often "regard these nations as foreign policy irrelevancies; except when poverty leads to chaos and extremism, in which case they suddenly turn into military or terrorist threats". The usual policy toward such countries is akin to the policy of a doctor who instead of preventing a disease waits until it turns into a full-blown infection, and then delivers medication that almost kills the patient without getting rid of the cause. Sadly for both parties in this country, drones are a much bigger priority than dams. This has to change.
We are still struggling with the goal laid out by John Kennedy in his Peace Speech, but Kennedy also realistically realized that reaching the goal would be a gradual and piecemeal process. He made it even clearer in his inaugural speech:

"There is no single, simple key to this peace; no grand or magic formula to be adopted by one or two powers. Genuine peace must be the product of many nations, the sum of many acts. It must be dynamic, not static, changing to meet the challenge of each new generation. For peace is a process -- a way of solving problems...(from the inaugural speech) All this will not be finished in the first 100 days. Nor will it be finished in the first 1,000 days, nor in the life of this administration, nor even perhaps in our lifetime on this planet. But let us begin."
Indeed. We do not know where it will end, but it is up to us to begin.

The birth of a new theory: Richard Feynman and his adversaries

Leading physicists discuss their field's most pressing problems
at Shelter Island in April 1947; including, among others, Julian
Schwinger, Richard Feynman and J. Robert Oppenheimer
This post was written on occasion of Richard Feynman's 100th birthday on May 11th and was first published on the website 3 Quarks Daily. It's the second in a pair of articles about two landmark meetings in postwar American physics.
A new theory seldom comes into the world like a fully formed, beautiful infant, ready to be coddled and embraced by its parents, grandparents and relatives. Rather, most new theories make their mark kicking and screaming while their fathers and grandfathers try to disown, ignore or sometimes even hurt them before accepting them as equivalent to their own creations. Ranging from Darwin’s theory of evolution by natural selection to Wegener’s theory of continental drift, new ideas in science have faced scientific, political and religious resistance. There are few better examples of this jagged, haphazard, bruised birth of a new theory as the scientific renaissance that burst forth in a mountain resort during the spring of 1948.
April 2, 1948. Twenty-eight of the country’s top physicists met at the Pocono Manor Hotel near the Delaware Water Gap in Pennsylvania. Kept apart from their first love of fundamental research in physics by the war, they were eager to regroup and rethink the problems which had plagued the heights of their profession before they were called away for war duty to Los Alamos, Cambridge and Chicago.
The listing of participants provides a rare snapshot of one of those hallowed transitions in the history of science, a passing of the torch. Both the old and the new guards were there. The old guard was represented, among others, by Niels Bohr, Paul Dirac and Eugene Wigner – the men who had formulated and then shaped the material world in its quantum mechanical image during the 1920s and 30s. The new guard was represented by Richard Feynman, John Wheeler and Julian Schwinger – the swashbuckling young theorists who wanted to take quantum theory to new heights, even if it meant challenging the old wisdom. J. Robert Oppenheimer who led the conference represented a prophet of the middle ground; a guide joining old hands with new. In retrospect, a clash of worldviews seems almost inevitable.
The problem that was at the forefront of everyone’s attention was the plague of infinities. The infinities had started showing up just a few years after the quantum revolution had burst upon the world. Within a short span of five years or so, between 1925 and 1930, a handful of theorists in their twenties and thirties including Dirac, Werner Heisenberg, Erwin Schrödinger, Max Born and Wolfgang Pauli had completely reworked the foundations of our physical picture of the world. Niels Bohr who along with Albert Einstein and Max Born had kicked off the revolution a decade before was their avuncular godfather; Einstein himself was a reluctant pioneer. The father of quantum mechanics, Max Planck, had showed that energy came only in discrete packets; now these new frontiersmen extended the concept to every physical entity in the universe. The work done by the quantum pioneers revealed a world steeped in probabilities rather than certainties, a world where you could not know the values of even simple parameters like a particle’s position and momentum to infinite precision, a world where particles and waves blurred themselves into each other in a mirage of probability amplitudes and wavefunctions. It was this fundamental ambiguity about what you could know about subatomic entities that led to Einstein’s famous remark about God playing dice.
And yet the theory was accuracy exemplified. Whatever its mathematical and philosophical ambiguities, it kept on providing astonishingly accurate answers to both old and new problems in disparate branches of physics. Whether it was a matter of calculating the frequency of radiation emitted by electrons transitioning in an atom or the resistance of metals to electrical current, quantum theory gave you the right answers, marching in perfect lockstep with numbers from experiment. It seemed to work for virtually every problem you threw it at. Except one.
That puzzle was the interaction between light and matter. It turned up in the simplest of situations, such as calculating the energy of an electron in an atom, and was recognized by the father of quantum field theory, Paul Dirac. Quantum field theory is the most comprehensive description of the world of subatomic particles, and in its simplest sense involves subjecting both particles and the electromagnetic fields which surround them to the rules of quantization. But even a cursory glimpse at the issue made the intractability clear: the energy of a charge in an electromagnetic field – called the ‘self energy’ – is given by the ratio of the strength of the field at various points and the distances between the charge and these points. One calculates the total self-energy by summing up the values at every point. The difficulty is obvious when you think about it: at distances close to zero, you divide by an increasingly smaller number, blowing up the value precipitously. Exactly at the location of the charge, where the distance is zero, the energy becomes infinite; the writers Robert Crease and Charles Mann have described it as a plane being blown to smithereens in its own wake. Clearly this is an absurd result since every energy value which you measure in a real world laboratory is finite.
Starting in about 1930, this problem of infinite self-energy was tackled by many of the most brilliant theoreticians of their time without resolution: Oppenheimer, Heisenberg, the acerbic Wolfgang Pauli and his mild-mannered assistant Victor Weisskopf all described the problem and tried to resolve it in various ways. If anything the picture got even worse; instead of just one infinity, other infinities started rearing their ugly heads like the heads of the mythical Hydra. One of these infinities was pointed out by Dirac. It turns out that during its transition in an atom, an electron can briefly spit out a photon and reabsorb it; this seemingly ex nihilo act of creation is allowed by quantum mechanics as long as it’s done in an exceedingly small amount of time. The problem is that the energy between the electron and this so-called ‘virtual’ photon can be apportioned again in an infinite numbers of ways. If you sum up all these ways you again get the dreaded explosion of infinity.
There seemed to be no end to attempts to exorcising these infinities. Then war intervened, the community of American physicists was drawn up for work on radar and the bomb, and the community of European physicists, many of whom had already fled from Hitler and Mussolini and were scattered across at least two continents, joined them. There the matter of the infinities rested until 1947, when an extraordinary conference of physicists was organized at a small inn off the coast of Long Island near New York City. The Shelter Island conference later went down in history as the conference that kicked off the postwar rejuvenation of particle physics, but in April 1947 it still represented the first stirrings of a revolution. The conference was again chaired by Oppenheimer and included a mix of the old and young guards.
The attention of the participants at Shelter Island was focused on one number of singular importance. Sometimes it takes hard experiment to cut the theoretical Gordian knot. While the theorists had struggled with infinities even before the war, they were galvanized by the experiments of Willis Lamb and his colleague Robert Retherford. Lamb was one of those rare breeds of scientist who are comfortable with both theory and experiment. Combining highly skilled techniques in microwave spectroscopy developed during wartime work on radar with a good understanding of the problems with infinities plaguing quantum field theory, Lamb and Retherford discovered a slight difference in energy between two states of the hydrogen atom at a place where the original Dirac theory predicted no difference. In science revolutions are sometimes engineered by the slightest and most mundane-looking discrepancies in the behavior of matter – Arthur Eddington’s measurement of a tiny shift in the position of the stars predicted by Einstein’s general theory of relativity comes to mind – and the Lamb Shift is as good an example as any of this pivot point in scientific history.
The Lamb Shift is also a telling example of what happens when multiple ideas are in the air, vying with each other for publicity and survival. In the conference Weisskopf had already presented a calculation that could potentially explain the shift, and so had one of the members of the old guard, Hendrik Kramers, who had been Niels Bohr’s assistant. But neither of these efforts got rid of the infinities. It took Hans Bethe with his absolutely mastery of synthesizing different ideas to take the Lamb Shift to its logical conclusion. Nobody surpassed Bethe in his knowledge of multiple branches of physics and his ability to calculate real world answers using the right combination of mathematical techniques and approximations. During a train journey back from Shelter Island, Bethe had the stroke of insight to attempt a calculation of the Lamb Shift using a non-relativistic approximation that ignored effects due to Einstein’s special theory of relativity. In addition, he introduced a physically sensible cutoff for the infinities to get a finite answer. Everyone knew that a correct quantum field would have to include special relativity, so it took some courage on Bethe’s part to attempt a non-relativistic calculation. Strikingly, the result was very close to experiment; 1040 MHz vs 1000 MHz. It still wasn’t the exact answer, but Bethe’s calculation was a shot in the arm, a signal that the theorists’ thinking was on the right track. It was also a fine illustration of how sometimes even a strictly non-realistic, approximate model can guide you in the right direction.
Bethe’s work breathed new life into the work of many others, including Weisskopf and Lamb, both of whom kicked themselves for not thinking about it first. But the biggest impact was on two young members of the group who had already distinguished themselves by their brilliant work during the war – Julian Schwinger and Richard Feynman.
Feynman and Schwinger were two of the earliest products of the American school of theoretical physics. Until the 1930s or so, most American theorists had to go to Europe to learn quantum mechanics at the feet of the masters: Niels Bohr in Copenhagen, Max Born in Göttingen and Arnold Sommerfeld in Munich. In the 30s the center of research started moving to the United States, partly engendered by the exodus of Jewish refugee physicists and partly because of the creation of prominent schools of physics by American physicists themselves. Two of the most prominent schools were Robert Oppenheimer’s at Berkeley and John Archibald Wheeler’s at Princeton. Schwinger came from Oppenheimer’s school; Feynman came from Wheeler’s.
Both Schwinger and Feynman were from New York, but otherwise were very different characters. Feynman was a practical joker who cracked safes, disdained pretension, played the bongos and spoke in colloquial New York City slang. While he had been recognized as a brilliant physicist, he still did not enjoy the star power that Schwinger – a child prodigy who had written his first paper on quantum electrodynamics when he was sixteen – did. Unlike Feynman, the leonine Schwinger wore expensive suits, drove a Cadillac and was the very picture of the distinguished academic. Physicists of the stature of Bethe and Fermi had already paid homage to Schwinger and everyone thought him to be the future. At Shelter Island they had listened to him with reverence; as Oppenheimer put it, “When other physicists do a calculation they want to tell you how they do it; when Schwinger does a calculation he wants to tell you that only he can do it.”
After Shelter Island, the physicists went off to their universities and laboratories, attempting a full calculation of quantum electrodynamics that was relativistic. Schwinger managed to calculate a precise value for the magnetic moment of the electron – a parameter for which comparison between theory and experiment would come to represent the most accurate agreement in all of physics – for the first time in November 1947. Most importantly, the calculation gave a finite answer. One of the elder statesmen of physics, a tough-minded New Yorker named Isidor Rabi, rushed off a note to Bethe: “Schwinger’s calculation is as accurate as yours. God is Great!”.
Feynman was on a completely different track. Working with John Wheeler, he had come up with a novel approach called the path integral approach that included particles traveling backward and forward in time. His bookkeeping technique used a principle familiar from classical mechanics, the principle of least action, that minimized the energy a particle takes in order to travel from A to B. For quantum theory, in Feynman’s hands, one had to consider every single trajectory that the particle would take in order to calculate the most probable one. This so-called 'sum over histories' approach was completely different from anyone else's, although its first trappings had been anticipated by the always prescient Dirac in a paper which Feynman had eagerly read in the Princeton library as a graduate student. Feynman represented his calculations in the form of squiggly and straight lines symbolizing virtual and real particles traveling backward and forward in time. When the Pocono Conference rolled around, he was ready to dazzle his listeners.
Unfortunately Feynman was up against two major obstacles. One was the traditional and hidebound old physics establishment. The other was Julian Schwinger. Schwinger had just given a marathon six-hour talk in which he brought all the formal machinery of mathematical physics to bear on calculating finite answers for electron-photon interactions. His talk was described by some as a virtuoso violin performance, more technique than comprehension. By one account, only Hans Bethe and Enrico Fermi – men who were particularly known for their stamina and powers of concentration – stayed awake and alert enough to follow the entire presentation.
Then Feynman took the podium. Knowing that his listeners would have trouble following the novel derivation of his results, he instead proceeded to simply show them worked out examples. His strategy was understandable, but he was attempting something akin to simply showing worked out examples in a mathematics textbook without showing the underlying theory. For the mandarins of theory who had spent their entire careers trying to take apart and understand all the gory details of how nature worked, this impressionistic-looking display was most unsatisfactory. Immediately they interrupted.
Edward Teller, the Hungarian-born physicist who hadn’t yet achieved the infamous moniker of ‘father of the hydrogen bomb’, thought that Feynman was violating the exclusion principle, a central tenet of physics and chemistry discovered by Wolfgang Pauli that precludes having two electrons with the same energy and spins in the same state. Dirac asked Feynman about a mathematical matrix that carried particle probabilities forward in time. He was wondering about a recondite mathematical property of a matrix called the unitary property that had nonetheless been key in understanding all particle interactions in quantum mechanics. Finally, the elder statesman of physics, the father of them all, Niels Bohr interrupted. Bohr had been impressed at Los Alamos by Feynman’s willingness to brazenly question all authority, including Bohr’s. He now took umbrage at the unfamiliar thicket of squiggles representing particle trajectories. Already in the 1930s, Bohr said in his soft but firm voice, we knew that the classical notion of a trajectory does not make sense in quantum mechanics. Now Feynman seemed to be violating this basic tenet of quantum theory. Bohr strode up to the stage and, standing next to Feynman, speaking in his notorious mumble, delivered a humiliating lecture that seemed to convey Feynman’s lack of understanding of even elementary ideas.
Feynman realized that it was hopeless; Teller was obsessed with a basic fact of quantum mechanics, Dirac was hung up over mathematical formalism, Bohr was still stuck in the 1930s. Clearly his approach was too unconventional and too novel for the old guard. The only way they would listen would be if he laid it all out in an academic paper. History was witnessing the passing of the torch between generations, but for the time being it would have to allow the old generation to win the battle, even if they lost the war. Feynman was undoubtedly on the right track. His new theory had given the right answers for all outstanding problems posed by the new physics. And after his talk, in the next few days, he compared his results with Schwinger’s. These two rivals nonetheless had a healthy respect for each other’s unique approaches, and they realized that were both traversing different trajectories on the mountain of truth.
Within a year Feynman had written up a seminal paper spurred by the disappointment and urgency he witnessed at Pocono. “Space-Time Approach to Quantum Mechanics” would become one of the most important physics papers of the twentieth century. In time, Feynman diagrams would come to dot the pages of the leading physics journals like an art form, much like the native art found on the caves at Lascaux represented its creator’s innermost desires and motivations. And like God bringing, in Schwinger’s words, “computation to the masses”, Feynman would have his own prophet: his colleague Freeman Dyson would unify Schwinger and Feynman’s versions of the promised land and deliver a set of powerful tools that would allow physicists to apply the duo’s techniques to problems in fields ranging from particle physics to astrophysics. And finally, like a voice from the deep, a lonesome letter would come floating to America from the troubled East, where a physicist named Sin-Itiro Tomonaga would have astonishingly worked out Schwinger’s formulation of QED in the isolation and destruction of wartime Japan. In time, QED would provide the most astonishingly accurate between theory and experiment in the history of physics.
But it had all started at Shelter Island and Pocono, where history changed hands and took a new direction, where a thirty year old physicist presented a novel vision; in Dyson’s words, “this wonderful vision of the world as a woven texture of world lines in space and time, with everything moving freely, a unifying principle that would either explain everything or explain nothing.”