David Bohm, his science and his exile
A thirty-year struggle for recovering American citizenship
Olival Freire Jr.
Instituto de Fisica - UFBa
Salvador - Bahia - BRASIL
When David Bohm and Richard Feynman concluded their Physics theses under Oppenheimer, in Berkeley, during the first half of the 1940s, they were among the most promising students of their generation in American physics. After the war, however, their fates were very different. Feynman arrived at the zenith of his scientific career always in the US. In 1951 Bohm was forced to leave US forever. Before that, he got a position in Princeton, carried on his researches on plasma theory, and published, in 1951, a well praised graduate textbook entitled "Quantum Theory". At that moment, his life suffered two important changes. He became a victim of the McCarthy anticommunist hysteria and changed his research interests to a heterodox field of physics, developing a causal interpretation of quantum mechanics against the standard view on that subject. Those two changes were a turning point in his personal and scientific life.
In the McCarthys times, he could not survive in American academia. The first scientific position he was able to get was in Brazil, so he left US in October 1951. In Brazil, American officials confiscated his passport and told him that he could only get it back again to return to his native country. Without passport Bohm could not travel abroad to intensify his scientific work and the only way out he foresaw was to get Brazilian citizenship. It was as a Brazilian that Bohm left Brazil in January 1955 to take a position at the Technion, in Haifa. Two years later he went to Bristol, and since 1960 until his last days, in 1992, he worked at the Birkbeck College, in London. There he knew he had lost his American citizenship and began his 30-year struggle for recovering it, while living as a Brazilian citizen and dreaming of returning to live in US.
He always kept his main scientific interests in the unorthodox field he entered in 1951. But, as time went by, that field became a regular field of research in physics, named foundations of quantum mechanics. At the turn of the century, his name was considered one of the most gifted protagonists of a research field that is developing quickly and even promises innovative technological applications. The centenary edition of Physical Review considered his paper on causal interpretation one of the most important papers published in the leader journal of American physics.
He was not only a victim of the Cold War times, but also suffered from the crisis of Communism. He was able of keep his Marxist ideology even in the hard times of McCarthy, but he gave it up in 1957, shaken by the invasion of Hungary by Soviet troops. However, he did decide not to pay the price required by American authorities, in 1960, to recover his American citizenship: to make public and ostensive pronouncements against Communism. Since then Bohm has become largely known not by his Marxist inclinations, but for his new intellectual tendencies towards East thoughts of Krishnamurti.
A life with so many vicissitudes meets many questions, suggested by the Workshop on "Migrant Scientist in the Twentieth Century" and some others concerning the relationships between his scientific works and his ideological views. Some of those questions have already received some answers in the literature, all the more because Bohms works have been object of a number of philosophical and historical studies, besides the scientific ones. So, Wang (1992) believed McCarthysm forced him to abandon physics research for several years, including those of the Brazilian exile; Olwell (1999) thought that American physics lost with Bohms leaving, but also considered that Bohms research program in quantum physics suffered with his insulation in Brazil; Freire, Paty & Rocha Barros (2002) saw the absence of new results in the causal interpretation as a major hindrance to the acceptation of that approach. Cross (1991) believed that Bohms ideas on quantum mechanics were just a reflection of the Marxist diagnosis of the existence of a crisis in physics during the 1950s. Kojevnikov (2002) saw Marxist influence on Bohms approach to plasma physics as a positive heuristic tool. I do not intend to present a comprehensive study about Bohms activities, but just analyze, in detail, some of those questions. So, I will argue the following points: a) forced to live out of his country since his 34 years of age, Bohm was a typical case of somebody who suffered with the world political scenery after World War II. At the beginning he was a victim of the McCarthy hysteria, but only at the sunset of the Cold War could he recover his American citizenship; b) he was supported by one of the webs of scientific internationalism, very common in the 20th century. One of the knots of that web had the brilliance of the name of Albert Einstein, but it included, in a crucial moment of his life, a Brazilian connection. Support to Bohm in Brazil came from the young community of physicists (Tiomno, Leite Lopes, Schönberg, and de Moraes), from the autonomy of the University of São Paulo (in which the sociologist Fernando de Azevedo was instrumental as the referee of Bohms application), and, last but not least, from the new, even if fragile, Brazilian democracy born after the war. Bohms double condition of Marxist and Jew was not an unfavorable factor to the Brazilian support; on the contrary, this condition probably enlarged the desire of people to help him; c) its certain, as Olwell remarked, that American physics lost with his departure, but one cannot infer from his migration and tainted image as a McCarthy target, the reasons for the weak reception of his causal interpretation of quantum mechanics. Other factors could have been more effective; we argued elsewhere about the role played by the absence of new results, and one should include the dominant role of the Copenhagen interpretation. The same weak reception would mark another quantum heterodoxy at the same University of Princeton five years later. However, Hugh Everetts case was the opposite of David Bohms, as he was working for the Pentagon at the same time his "many-worlds" interpretation of quantum mechanics suffered a similar unfavorable reception by the Copenhagen interpretation supporters. In the same way, the De Broglie-Vigier group in Paris, in a very different context, working with the same causal interpretation, suffered an analogous weak reception. So I think that Bohms migration was not an important factor for the weak initial reception of his scientific work; d) Bohms staying in Brazil and in Israel was very important to the institutions which hosted him, even if he was never satisfied with the intellectual ambiance at those countries. In Brazil his work led to publications with Tiomno and Schützer. The French Vigier, the American Schiller, and the Argentine Bunge went to Brazil to work with him. Bohm had meaningful debates with Schönberg. He also met and discussed his approach with Feynman, Rosenfeld and Rabi, while they were visiting Brazil. He went to Israel invited by Rosen, and there he met the student Y. Aharonov, with whom he got a seminal result in the foundations of quantum mechanics, the Aharonov-Bohm effect; e) and finally, I will argue that Marxist views were influent on and supportive of the causal interpretation, even if they were not the causative factor that Cross advocated. In the same way, Bohms sudden rupture with Marxism, in 1957, has played a role in the weakening of his emphasis on the causal description and in his search for new directions in science and philosophy, which included the ideas of wholeness and implicate order and his rapprochement of Krishnamurti. I would like to conclude by stating that his science and his life are a very useful instance for our learning of science and history in the last half of the 20th century.