The body of men and women who built the atomic bomb was vast, diverse, talented and multitudinous. Every conceivable kind of professional - from theoretical physics to plumber - worked on the Manhattan Project for three years over an enterprise that spread across the country and equaled the US automobile industry in its marshaling of resources like metals and electricity.
The project may have been the product of this sprawling hive mind, but one man saw both the essence and the implications of the bomb, in both science and politics, long before anyone else. Stepping off the curb at a traffic light across from the British Museum in London in 1933, Leo Szilard saw the true nature and the consequences of the chain reaction six years before reality breathed heft and energy into its abstract soul. In one sense though, this remarkable propensity for seeing into the future was business as usual for the Hungarian scientist. Born into a Europe that was rapidly crumbling in the face of onslaughts of fascism even as it was being elevated by revolutionary discoveries in science, Szilard grasped early in his youth both a world split apart by totalitarian regimes and the necessity of international cooperation engendered by the rapidly developing abilities of humankind to destroy itself with science. During his later years Szilard once told an audience, "Physics and politics were my two great interests". Throughout his life he would try to forge the essential partnership between the two which he thought was necessary to save the human species from annihilation.
A few years ago, physicist and author William Lanouette brought out a new, revised edition of his definitive, sensitive and sparkling biography of Szilard. It is essential reading for those who want to understand the nature of science, both as an abstract flight into the deep secrets of nature and a practical tool that can be wielded for humanity's salvation and destruction. As I read the book and pondered Szilard's life I realized that the twentieth century Hungarian would have been right at home in the twenty-first. More than anything else, what makes Szilard remarkable is how prophetically his visions have played out since his death in 1962, all the way to the year 2014. But Szilard was also the quintessential example of a multifaceted individual. If you look at the essential events of the man's life you can see several Szilards, each of whom holds great relevance for the modern world.
There's of course Leo Szilard the brilliant physicist. Where he came from precocious ability was commonplace. Szilard belonged to the crop of men known as the "Martians" - scientists whose intellectual powers were off scale - who played key roles in European and American science during the mid-twentieth century. On a strict scientific basis Szilard was perhaps not as accomplished as his fellow Martians John von Neumann and Eugene Wigner but that is probably because he found a higher calling in his life. However he certainly did not lack originality. As a graduate student in Berlin - where he hobnobbed with the likes of Einstein and von Laue - Szilard came up with a novel way to consolidate the two microscopic and macroscopic aspects of the science of heat, now called statistical mechanics and thermodynamics. He also wrote a paper connecting entropy and energy to information, predating Claude Shannon's seminal creation of information theory by three decades. In another prescient paper he set forth the principle of the cyclotron, a device which was to secure a Nobel Prize for its recognized inventor - physicist Ernest Lawrence - more than a decade later.
Later during the 1930s, after he was done campaigning on behalf of expelled Jewish scientists and saw visions of neutrons branching out and releasing prodigious amounts of energy, Szilard performed some of the earliest experiments in the United States demonstrating fission. And while he famously disdained getting his hands dirty, he played a key role in helping Enrico Fermi set up the world's first nuclear reactor.
Szilard as scientist also drives home the importance of interdisciplinary research, a fact which hardly deserves explication in today's scientific world where researchers from one discipline routinely team up with those from others and cross interdisciplinary boundaries with impunity. After the war Szilard became truly interdisciplinary when he left physics for biology and inspired some of the earliest founders of molecular biology, including Jacques Monod, James Watson and Max Delbruck. His reason for leaving physics for biology should be taken to heart by young researchers - he said that while physics was a relatively mature science, biology was a young science where even low hanging fruits were ripe for the picking.
Szilard was not only a notable theoretical scientist but he also had another strong streak, one which has helped so many scientists put their supposedly rarefied knowledge to practical use - that of scientific entrepreneur. His early training had been in chemical engineering, and during his days in Berlin he famously patented an electromagnetic refrigerator with his friend and colleague Albert Einstein; by alerting Einstein to the tragic accidents caused by leakage in mechanical refrigerators, he helped the former technically savvy patent clerk put his knowledge of engineering to good use (as another indication of how underappreciated Szilard remains, the Wikipedia entry on the device is called the "Einstein refrigerator"). Szilard was also finely attuned to the patent system, filing a patent for the nuclear chain reaction with the British Admiralty in 1934 before anyone had an inkling what element would make it work, as well as a later patent for a nuclear reactor with Fermi.
He also excelled at what we today called networking; his networking skills were on full display for instance when he secured rare, impurity-free graphite from a commercial supplier as a moderator in Fermi's nuclear reactor; in fact the failure of German scientists to secure such pure graphite and the subsequent inability of the contaminated graphite to sustain fission damaged their belief in the viability of a chain reaction and held them back. Szilard's networking abilities were also evident in his connections with prominent financiers and bankers who he constantly tried to conscript in supporting his scientific and political adventures; in attaining his goals he would not hesitate to write any letter, ring any doorbell, ask for any amount of money, travel to any land and generally try to use all means at his disposal to secure support from the right authorities. In his case the "right authorities" ranged, at various times in his life, from top scientists to bankers to a Secretary of State (James Byrnes), a President of the United States (FDR) and a Premier of the Soviet Union (Nikita Khrushchev).
I am convinced that had Szilard been alive today, his abilities to jump across disciplinary boundaries, his taste for exploiting the practical benefits of his knowledge and his savvy public relations skills would have made him feel as much at home in the world of Boston or San Francisco venture capitalism as in the ivory tower.
If Szilard had accomplished his scientific milestones and nothing more he would already have been a notable name in twentieth century science. But more than almost any other scientist of his time Szilard was also imbued with an intense desire to engage himself politically - "save the world" as he put it - from an early age. Among other scientists of his time, only Niels Bohr probably came closest to exhibiting the same kind of genuine and passionate concern for the social consequences of science that Szilard did. This was Leo Szilard the political activist. Even in his teens, when the Great War had not even broken out, he could see how the geopolitical landscape of Europe would change, how Russia would "lose" even if it won the war. When Hitler came to power in 1933 and others were not yet taking him seriously Szilard was one of the few scientists who foresaw the horrific legacy that this madman would bequeath Europe. This realization was what prompted him to help Jewish scientists find jobs in the UK, at about the same time that he also had his prophetic vision at the traffic light.
It was during the war that Szilard's striking role as conscientious political advocate became clear. He famously alerted Einstein to the implications of fission - at this point in time (July 1939) Szilard and his fellow Hungarian expatriates were probably the only scientists who clearly saw the danger - and helped Einstein draft the now iconic letter to President Roosevelt. Einstein's name remains attached to the letter, Szilard's is often sidelined; a recent article about the letter from the Institute for Advanced study on my Facebook mentioned the former but not the latter. Without Szilard the bomb would have certainly been built, but the letter may never have been written and the beginnings of fission research in the US may have been delayed. When he was invited to join the Manhattan Project Szilard snubbed the invitation, declaring that anyone who went to Los Alamos would go crazy. He did remain connected to the project through the Met Lab in Chicago, however. In the process he drove Manhattan Project security up the wall through his rejection of compartmentalization; throughout his life Szilard had been - in the words of the biologist Jacques Monod - "as generous with his ideas as a Maori chief with his wives" and he favored open and honest scientific inquiry. At one point General Groves who was the head of the project even wrote a letter to Secretary of War Henry Stimson asking the secretary to consider incarcerating Szilard; Stimson who was a wise and humane man - he later took ancient and sacred Kyoto off Groves's atomic bomb target list - refused.
Szilard's day in the sun came when he circulated a petition directed toward the president and signed by 70 scientists advocating a demonstration of the bomb to the Japanese and an attempt at cooperation in the field of atomic energy with the Soviets. This was activist Leo Szilard at his best. Groves was livid, Oppenheimer - who by now had tasted power and was an establishment man - was deeply hesitant and the petition was stashed away in a safe until after the war. Szilard's disappointment that his advice was not heeded turned to even bigger concern after the war when he witnessed the arms race between the two superpowers. In 1949 he wrote a remarkable fictitious story titled 'My Trial As A War Criminal' in which he imagined what would have happened had the United States lost the war to the Soviets; Szilard's point was that in participating in the creation of nuclear weapons, American scientists were no less or more complicit than their Russian counterparts. Szilard's take on the matter raised valuable questions about the moral responsibility of scientists, an issue that we are grappling with even today. The story played a small part in inspiring Soviet physicist Andrei Sakharov in his campaign for nuclear disarmament. Szilard also helped organize the Pugwash Conferences for disarmament, gave talks around the world on nuclear weapons, and met with Nikita Khrushchev in Manhattan in 1960; the result of this amiable meeting was both the gift of a Schick razor to Khrushchev and, more importantly, Khrushchev agreeing with Szilard's suggestion that a telephone hot-line be installed between Moscow and Washington for emergencies. The significance of this hotline was acutely highlighted by the 1962 Cuban missile crisis. Sadly Szilard's later two attempts at meeting with Khrushchev failed.
After playing a key role in the founding of the Salk Institute in California, Szilard died peacefully in his sleep in 1964, hoping that the genie whose face he had seen at the traffic light in 1933 would treat human beings with kindness.
Since Szilard the common and deep roots that underlie the tree of science and politics have become far clearer. Today, when science and facts seem under attack and where truth constantly threatens to become a casualty, we need scientists like Szilard to stand up for science every time a scientific issue political ideology. When Szilard pushed scientists to get involved in politics it may have looked like an anomaly, but today it's not simply optional. All of us need to be involved in small and big ways. At the same time, it's worth noting that Szilard's motto for the interaction of science with politics was often one of accommodation. He was always an ardent believer in the common goals that human beings seek, irrespective of the divergent beliefs that they may hold. He was also an exemplar of combining thought with action, projecting an ideal meld of the idealist and the realist. Whether he was balancing thermodynamic thoughts with refrigeration concerns or following up political idealism with letters to prominent politicians, he taught us all how to both think and do. As interdisciplinary scientist, as astute technological inventor, as conscientious political activist, as a troublemaker of the best kind, Leo Szilard leaves us with an outstanding role model and an enduring legacy. It is up to us to fill his shoes.