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BRIEFING SERIES

From Haber to Heisenberg and Beyond: The Role of Scientists in the Acquisition of WMD
March 26, 2002
Marvin M. Miller
Security Studies Program & Department of Nuclear Engineering
Massachusetts Institute of Technology

Acquisition of Weapons of Mass Destruction: The Role of Scientists

Introction: The Responsibility of Scientists
For most scientists of my acquaintance, the fundamental notion of professional responsibility is to tell the truth. That is, to reach conclusions based on all the scientific evidence available to them, whether or not it conflicts with previous opinions and positions, and to share this evidence with other scientists. This criterion of responsibility is captured well in the following statement by Albert Einstein, which is engraved on the base of his statue in front of the National Academy of Sciences building in Washington, DC:

"The right to search for the truth implies also a ty not to conceal any part of what one has recognized to be true."

In practice, this criterion of scientific responsibility can be quite demanding: given the highly competitive nature of many disciplines of contemporary science and technology, including the potential for considerable prestige and financial gain, it isn't surprising that scientists sometimes pay “selective attention” to the evidence. While regrettable, such behavior is unlikely to have catastrophic consequences for society as a whole. In most cases, unsubstantiated claims are eventually exposed, although indivial scientists may have their careers or lives ruined in the process.

The subject of this paper concerns a different dimension of the notion of scientific responsibility, the choice of what to work on, rather than the degree of honesty with which this work is pursued. Specifically, I discuss what has motivated scientists ring the 20th century to help develop nuclear, chemical, and biological weapons, i.e., the so-called weapons of mass destruction (WMD), and then consider the feasibility of providing disincentives for such work as a means of minimizing the risk of their further proliferation. In the next section, I examine what factors were most important in the decisions of several prominent scientists to work on WMD. This is followed by a discussion of “the other side of the coin”: the practicality and the wisdom of trying to dissuade scientists not to work on WMD. I conclude with some observations about the need for scientists to take a more active interest in such ethical issues, and the difficulties involved in bringing this to pass.

Scientists and WMD in the 20th Century
The best-known and most controversial example of the involvement of scientists in the development of WMD was the German atomic bomb project ring World War II, particularly the involvement of the famous physicist Werner Heisenberg. I begin my mini-survey of the scientists and WMD issue with this episode, starting with some background material.

The fission of uranium was first identified by two German chemists, Otto Hahn and Fritz Strassman, in December 1938. Although this finding was a complete surprise to most scientists, its theoretical explanation followed quickly as did experiments in several countries which confirmed that neutrons are released in the fission process. This implied that large amounts of energy might be released in a macroscopic mass of uranium either in a controlled manner over time or instantaneously in a powerful explosion via a neutron chain reaction. For the latter purpose it was clear that the uranium would have to be enriched, i.e., the concentration of the isotope U-235 would have to be increased above its small value in natural uranium by isotope separation. However, until the spring of 1940, no one had made an accurate estimate of the minimum amount of enriched uranium that would be needed for a uranium bomb, a quantity which became known as the critical mass. This was a key consideration because the processes of isotope separation known at that time were very technically demanding, and if the critical mass was as large as the initial estimates - on the order of tons to tens of tons - a uranium nuclear bomb might not be feasible.

The result of the calculation of the critical mass of fully enriched (i.e., 100% U-235) uranium made by Rudolph Peierls and Otto Frisch in England in the spring of 1940 - on the order of kilograms not tons - was quickly transmitted to the US. It gave fresh impetus to the American atomic bomb project which was initiated in 1939 largely as the result of the concerns of prominent refugee scientists such as Leo Szilard, Eugene Wigner, and Enrico Fermi who feared that Germany and hence the Nazi regime would get the bomb first. Such fears seemed well-founded at the time, and persisted until the last few months of the war in Europe. In 1939, Germany had access to ample supplies of uranium from mines in occupied Czechoslovakia, and by spring 1940, also from stocks in occupied Belgium. Moreover, despite the departure in the 1930s of Peierls, Frisch, Szilard et al, Germany retained a cadre of world-class scientists, in particular, Werner Heisenberg, who received the Nobel prize in physics in 1933, and was still at the height of his intellectual powers.

Although Heisenberg and the other German scientists started research on the atomic bomb in 1939, they never proced one. The reason for this is at the heart of the controversy surrounding the German atomic bomb project. The two poles of opinion on this question are presented in the books by Rose and Powers cited in reference #1. Powers argues that Heisenberg et al knew how to make a bomb, but that Heisenberg's distaste for the Nazi regime led him to quietly but effectively sabotage the project. Rose counters that moral scruples had nothing to do with it: Heisenberg was a German patriot who made his peace with the Nazi regime, but who also made an early and crucial overestimate of the critical mass of uranium which led him to believe that there was no chance of completing the manufacture of a bomb ring the war. As a consequence, he did not press the government for a crash program, and only limited resources were allocated to it. Most knowledgeable observers are now inclined to Rose's view, which is shared by the author.

The key point is that many of the German scientists, Heisenberg in particular, disliked the Nazi regime, yet as patriots who loved their country they decided that they could not refuse to work for their government, in particular on the development of an atomic bomb. After the war, Heisenberg argued that the central moral issue was that atomic bombs were intrinsically bad, and should not have been developed by anyone. Rose strenuously rejects this position:

"The fallacy here is that it is not atomic bombs that are the primary moral problem, but rather the evilness of Nazi Germany. By suppressing the Nazi and the Allied contexts, Heisenberg creates a false symmetry between the moral predicaments of the Allied and German scientists. It is as though the scientists are acting in a political vacuum simply as scientists, rather than as fighters for their respective causes. Given this political neutralism, the action of Allied physicists in choosing to manufacture an atomic bomb thus becomes morally reprehensible. Heisenberg never says anything in his accounts about the fact that the Allied scientists were behaving morally by virtue of the fact that they were developing weapons for the defense of a moral cause against an evil one."

From all accounts, the above was the prevailing view among the Allied bomb scientists. The Nazi regime was the epitome of evil, and Germany might win the war and then dominate the world if it developed an atomic bomb first. However, even when it became clear in late 1944 that the Germans had abandoned their bomb project, the great majority of the scientists involved in the Manhattan Project continued their work with undiminished zeal, and the focus of the project shifted seamlessly from Germany to the possible use of the bomb against Japan. Although some scientists were opposed to its use against civilian populations, it was the destruction of Hiroshima and Nagasaki that brought home to scientists and the public alike the horror of nuclear devastation and started the ongoing debate about the morality of the possession and possible use of nuclear and other WMD.

The disagreement between Heisenberg and Rose is central to the issue of the morality of the involvement of scientists in work on such weapons, and I return to it later in the paper. First, I continue my mini-survey of well-known scientists who worked on WMD in the 20th century, beginning with two whose basic motivation was the same as Heisenberg's, patriotic ty to one's country.

The first is Fritz Haber (1868-1934), the Jewish-born, German chemist, who won the Nobel Prize in chemistry in 1918 for the discovery of a process for the synthesis of ammonia from nitrogen and hydrogen, and is also known as the father of chemical warfare. At the outbreak of World War I in 1914, Haber immediately placed the facilities of the Kaiser Wilhelm Institute for Physical Chemistry in Berlin, of which he was the director, at the disposal of the German Government. In his son's words:

"Haber's patriotism was unusual even in an age where jingoism, into which it so frequently spills over, was condoned. He was a Prussian, with an uncritical acceptance of the State's wisdom, as interpreted by bureaucrats, many of them intellectually his inferiors. He was also ambitious, determined to succeed, and well aware that his Jewish origins was both obstacle and spur. His involvement in chemical warfare began in December 1914 and was marked for the ration by strong purpose, great energy, a practical turn of mind, and outstanding administrative ability. Haber's greatest successes came in 1915 - the year of the first gas attacks and the organization of gas-mask proction - but his most important role was played in the last two years of the war when he tendered advice at the highest level and was officially in charge of German gas supplies and gas protection."

Thus, Haber's involvement with the German chemical weapons program in World War I was marked by much greater enthusiasm and accomplishment than Heisenberg's participation in the German atomic bomb project in World War II. Indeed, the reference to his “strong purpose, great energy, practical turn of mind, and outstanding administrative ability” is much more reminiscent of the qualities that characterized J. Robert Oppenheimer's and Igor Kurchatov's leadership of the US and Soviet atomic bomb projects, respectively. However, unlike Heisenberg and Oppenheimer, Haber never tried to minimize his role or express any moral misgivings about it, at least not publicly. On the contrary, after the war he denied that Germany had violated the Hague Conventions of 1899 and 1907 which expressly prohibited the use of “asphyxiating or deleterious gases” and “poison or poisoned weapons”. He also argued that gas did not cause une suffering and therefore was not inhuman, and was very critical of scientists, particularly Germans, who did not share his views on the subject.

In fairness, there were many people on both sides in World War I who condoned the development of chemical weapons. Indeed, the US, England, and France all developed and used gas against the Germans ring the war, and to that end many scientists were willing participants. After the war, the strongest misgivings against chemical weapons was the concern that non-combatants would be deliberately or inadvertently targeted in future conflicts, and that research would lead to the development of more potent chemical agents which could cause injury and death on a wide scale extending to cities or even countries. Both these concerns have materialized, but as L. K. Haber notes chemical weapons were not used by either side in World War II against either troops or civilians because of a fear of retaliation and the inadequacy of means to protect the home populations.

As for Haber, he remained a German patriot to the end. When Hitler became Chancellor of Germany in 1933, Jewish academics were purged, and Haber resigned as director of the Kaiser Wilhelm Institute of Physical Chemistry and emigrated to England. Still, in his farewell letter to his institute colleagues, he could say:

"Im Frieden der Menschheit, im Kriege dem Vaterlande! (In peace for mankind, in war for the fatherland!)"

Another scientist, who also insisted on the primacy of the patriotic motive in working on WMD, in this case nuclear weapons, was Andrei Sakharov, whose considerable scientific achievements were overshadowed for many by his heroism in the pursuit of democratic change in the Soviet Union. In his memoirs, Sakharov comments at length on his decision to join in the development of nuclear weapons in 1948 at the age of 27.

"In 1948, no one asked whether I wanted to take part in such work. I had no real choice in the matter, but the concentration, total absorption, and energy that I brought to the task were my own. Now that some many years have passed, I would like to explain my dedication - not least to myself. One reason for it (though not the main one) was the opportunity to do “superb physics” (Fermi's comment on the atomic bomb program.) But I feel confident in saying that infatuation with a spectacular new physics was not my primary motivation; I could easily have found another problem in theoretical physics to keep me amused - as Fermi did, if you will pardon this immodest comparison. What was most important for me at the time, and also, I believe for Tamm and the other members of the group, was the conviction that our work was essential.

I understood, of course, the terrifying, inhuman nature of the weapons we were building. But the recent war had also been an exercise in barbarity; and although I hadn't fought in that conflict, I regarded myself as a soldier in this new scientific war (Kurchatov himself said we were “soldiers”, and this was no idle remark.) We were possessed by a true war psychology, which became still more overpowering after our transfer to the Installation.

Oppenheimer's judgment [not to develop an H-Bomb] was challenged by Edward Teller. Teller had experienced the 1919 communist revolution in his native Hungary, and he had a deep-seated mistrust for the socialist system. He insisted that only American military strength could restrain the socialist camp from an expansion that would threaten civilization and democracy and might trigger a third world war.

That is why Teller believed it necessary to speed development of an American H-Bomb and continue nuclear testing despite the genetic damage and other nonthreshold biological effects they implied In the 1940s and 1950s my position was much closer to Teller's, practically a mirror image (one had only to substitute “USSR” for “USA”, “peace and national security” for “defense against the communist menace”, etc.) - so that in defending his actions, I am also defending what I and my colleagues did at the time."

The forgoing is worthy of extended comment. I begin with Sakharov's downplaying of the opportunity to do “superb physics” as a motive for his enthusiastic participation in nuclear weapons development compared to service to his country.

The context here was the “recent war” in which 20 million Soviet citizens had been killed, and the strong feeling that the fruits of victory over Nazi Germany would be short-lived if the US maintained a monopoly on nuclear weapons. Sakharov and his colleagues were thus “possessed by a true war psychology”. By contrast, in the US from the end of World War II until the Soviet Union tested an atomic bomb in August 1949, there was little of this. Nuclear weapons development at Los Alamos continued apace, but the consensus view was that the US had a long lead over the Soviet Union in the nuclear domain. In this atmosphere, the opportunity to improve the Nagasaki bomb design had a strong appeal. One of the pioneers in this work was Theodore Taylor:

"I continue to insist that, although a concern for national well-being may have been what drew most scientists and engineers into the world's nuclear weapon programs, the work has remained fascinating for any who have been creatively inclined. I'm also convinced that the fascination persists in any environment in which pushing the physical limits for nuclear weaponry is encouraged...As a graate student at Berkeley I had even been strongly involved in student activism against the bomb. But within weeks after getting to Los Alamos [in 1949], I was thoroughly hooked on the fascinations for nuclear explosives. That addiction persists through the present, and I can only deal with it by abstinence."

I concur with Taylor's judgment. While the ability of the leadership of WMD programs to provide interesting technical challenges for scientists may be of secondary importance in times of war or crisis, real or manufactured, it becomes increasingly important when the war ends or the crisis cools. A contemporary example is the planned expenditure of considerable sums on various high-tech facilities at the US weapon laboratories as part of the Department of Energy's Stockpile Stewardship Program in order to attract first-rate scientists to the labs and thus maintain US expertise in nuclear weapons after the Cold War.

Another important aspect of Sakharov's statement are the references to two of his older scientific colleagues, the aforementioned Igor Kurchatov, the leader of the Soviet nuclear weapon program from its inception in 1943 until his death in 1960, and the distinguished physicist, Igor Tamm, who invited Sakharov to join the program in 1948. Sakharov's enthusiasm for his work was influenced by his admiration for the scientific prowess and dedication of these men. These qualities were shared by many of Sakharov's contemporaries in the program, e.g., the brilliant physicist Yakov Zeldovich, but his older mentors provided an important additional dimension: the example that any moral qualms about “the terrifying, inhuman nature of the weapons we were building” must be put aside because having such weapons was “essential” for the survival of the state. As Sakharov notes, such feelings were reinforced “after our transfer to the Installation”, a euphemism for the secret weapons laboratory at Arzamas-16 where the weapons team worked long hours under the watchful eyes of the KGB, isolated from any outside doubts and distractions.

In addition to all of the above, more mundane “sticks and carrots”, are undoubtedly influential in recruiting scientists to work on WMD. Sakharov refers to the fact that “no one asked whether I wanted to take part in such work, I had no real choice in the matter”. On the other hand, the prestige and material rewards he accrued for his contributions to the weapons program were substantial. Later, his concerns about “the horror, the real danger, and the utter insanity of thermonuclear warfare, which threatens everyone on earth”, led to the publication in 1968 of his essay, Reflections on Progress, Peaceful Coexistence, and Intellectual Freedom. This statement, as well as his subsequent writings and activities in defense of indivial victims of injustice in the Soviet Union, brought him into growing conflict with the Soviet authorities, which culminated in his forced exile in Gorky from 1980 to 1986. In December 1986, he was rehabilitated on the order of the Soviet Premier, Mikhail Gorbachev, and returned to Moscow, where he played an active role in the reform movement in the Soviet Union until his death in December 1989.

Sakharov left the Installation in 1969, and had no further connection with th