David Bohm

David Joseph Bohm FRS (December 20, 1917 – October 27, 1992) was an American scientist who has been described as one of the most significant theoretical physicists of the 20th century and who contributed unorthodox ideas to quantum theory, neuropsychology and the philosophy of mind.
Bohm advanced the view that quantum physics meant that the old Cartesian model of reality – that there are two kinds of substance, the mental and the physical, that somehow interact – was too limited. To complement it, he developed a mathematical and physical theory of "implicate" and "explicate" order. He also believed that the brain, at the cellular level, works according to the mathematics of some quantum effects, and postulated that thought is distributed and non-localised just as quantum entities are.
Bohm warned of the dangers of rampant reason and technology, advocating instead the need for genuine supportive dialogue, which he claimed could broaden and unify conflicting and troublesome divisions in the social world. In this, his epistemology mirrored his ontology. Due to his youthful Communist affiliations, Bohm was the subject of a federal government investigation in 1949, prompting him to leave the United States. He pursued his scientific career in several countries, becoming first a Brazilian and then a British citizen.
Bohm's main concern was with understanding the nature of reality in general and of consciousness in particular as a coherent whole, which according to Bohm is never static or complete but rather an unfolding process.

Youth and college

Bohm was born in Wilkes-Barre, Pennsylvania, United States, to a Hungarian Jewish immigrant father, Samuel Bohm, and a Lithuanian Jewish mother. He was raised mainly by his father, a furniture-store owner and assistant of the local rabbi. Despite being raised in a Jewish family, he became an agnostic in his teenage years. Bohm attended Pennsylvania State College (now Pennsylvania State University), graduating in 1939, and then the California Institute of Technology, for one year. He then transferred to the theoretical physics group directed by Robert Oppenheimer at the University of California, Berkeley, where he obtained his doctorate.

Bohm lived in the same neighborhood as some of Oppenheimer's other graduate students (Giovanni Rossi Lomanitz, Joseph Weinberg, and Max Friedman) and with them became increasingly involved in radical politics. He was active in Communist and Communist-backed organizations, including the Young Communist League, the Campus Committee to Fight Conscription, and the Committee for Peace Mobilization.

Work and doctorate

Manhattan Project contributions

During World War II, the Manhattan Project mobilized much of Berkeley's physics research in the effort to produce the first atomic bomb. Though Oppenheimer had asked Bohm to work with him at Los Alamos (the top-secret laboratory established in 1942 to design the atom bomb), the project's director, General Leslie Groves, would not approve Bohm's security clearance after seeing evidence of his politics (Bohm's friend, Joseph Weinberg, had also been suspected of espionage).

Bohm remained in Berkeley, teaching physics, until he completed his Ph.D. in 1943 by an unusual circumstance. According to Peat (see reference below, p. 64), "the scattering calculations (of collisions of protons and deuterons) that he had completed proved useful to the Manhattan Project and were immediately classified. Without security clearance, Bohm was denied access to his own work; not only would he be barred from defending his thesis, he was not even allowed to write his own thesis in the first place!" To satisfy the university, Oppenheimer certified that Bohm had successfully completed the research. Bohm later performed theoretical calculations for the Calutrons at the Y-12 facility in Oak Ridge, used to electromagnetically enrich uranium for the bomb dropped on Hiroshima in 1945.

McCarthyism and leaving the United States

After the war, Bohm became an assistant professor at Princeton University, where he worked closely with Albert Einstein. In May 1949, the House Un-American Activities Committee called upon Bohm to testify because of his previous ties to suspected Communists. Bohm invoked his Fifth amendment right to refuse to testify, and refused to give evidence against his colleagues.

In 1950 Bohm was arrested for refusing to answer HUAC's questions. He was acquitted in May 1951, but Princeton had already suspended him. After the acquittal, Bohm's colleagues sought to have him reinstated at Princeton, and Einstein reportedly wanted him to serve as his assistant, but Princeton President Harold W. Dodds decided not to renew Bohm's contract. His request to go to Manchester received Einstein's support but was unsuccessful. Bohm then left for Brazil to assume a professorship of physics at the University of São Paulo at Jayme Tiomno's invitation, and on Einstein's and Oppenheimer's recommendation.

Quantum theory and Bohm-diffusion

The Bohmian trajectories for an electron going through the two-slit experiment. A similar pattern was also observed for single photons.

During his early period, Bohm made a number of significant contributions to physics, particularly quantum mechanics and relativity theory. As a post-graduate at Berkeley, he developed a theory of plasmas, discovering the electron phenomenon known now as Bohm-diffusion. His first book, Quantum Theory, published in 1951, was well received by Einstein, among others. But Bohm became dissatisfied with the orthodox interpretation of quantum theory he had written about in that book. Starting from the realization that the WKB approximation of quantum mechanics leads to deterministic equations, and convinced that a mere approximation could not turn a probabilistic theory into a deterministic theory, he doubted the inevitability of the conventional approach to quantum mechanics.

Bohm's aim was not to set out a deterministic, mechanical viewpoint, but to show that it was possible to attribute properties to an underlying reality, in contrast to the conventional approach. He began to develop his own interpretation (the De Broglie–Bohm theory, also called the Pilot wave theory), the predictions of which agreed perfectly with the non-deterministic quantum theory. He initially referred to his approach as a hidden variable theory, but later referred to it as ontological theory, reflecting his view that a stochastic process underlying the phenomena described by his theory might one day be found. Bohm and his colleague Basil Hiley later stated that they had found their own choice of terms of an "interpretation in terms of hidden variables" to be too restrictive, especially since their variables, position, and momentum "are not actually hidden".

Bohm's work and the EPR argument became the major factor motivating John Bell's inequality, which rules out local hidden variable theories; the full consequences of Bell's work are still being investigated.

Brazil

After Bohm's arrival in Brazil on October 10, 1951, the US Consul in São Paulo confiscated his passport, informing him he could retrieve it only to return to his country. This reportedly frightened Bohm, and significantly lowered his spirits, as he had hoped to travel to Europe. He applied for and received Brazilian citizenship, but by law had to give up his US citizenship and was able to reclaim it only decades later, in 1986, after pursuing a lawsuit.

At the University of São Paulo, Bohm worked on the causal theory that became the subject of his publications in 1952. Jean-Pierre Vigier traveled to São Paulo, where he worked with Bohm for three months; Ralph Schiller (a student of cosmologist Peter Bergmann) was his assistant for two years; he worked with Tiomno and Walther Schützer; and Mario Bunge stayed to work with him for one year. He was in contact with Brazilian physicists Mário Schönberg, Jean Meyer, Leite Lopes, and had discussions on occasion with visitors to Brazil, including Richard Feynman, Isidor Rabi, Léon Rosenfeld, Carl Friedrich von Weizsäcker, Herbert Anderson, Donald Kerst, Marcos Moshinsky, Alejandro Medina, and the former assistant to Heisenberg, Guido Beck, who encouraged him in his work and helped him to obtain funding. The Brazilian CNPq explicitly supported his work on the causal theory and funded several researchers around Bohm. His work with Vigier was the beginning of a long-standing cooperation between the two and Louis De Broglie, in particular, on connections to the hydrodynamics model proposed by Madelung. Yet the causal theory met much resistance and skepticism, with many physicists holding the Copenhagen interpretation to be the only viable approach to quantum mechanics.

From 1951 to 1953, Bohm and David Pines published the articles in which they introduced the random phase approximation and proposed the plasmon.

Bohm and Aharonov form of the EPR paradox

In 1955 Bohm relocated to Israel, where he spent two years working at the Technion at Haifa. There he met Sarah ("Saral") Woolfson, whom he married in 1956.

In 1957 Bohm and his student Yakir Aharonov published a new version of the Einstein–Podolsky–Rosen (EPR) paradox, reformulating the original argument in terms of spin. It was this form of the EPR paradox that was discussed by John Stewart Bell in his famous paper of 1964.

Aharonov–Bohm effect

Schematic of double-slit experiment in which Aharonov–Bohm effect can be observed: electrons pass through two slits, interfering at an observation screen, with the interference pattern shifted when a magnetic field B is turned on in the cylindrical solenoid.

In 1957 Bohm relocated to the United Kingdom as a research fellow at the University of Bristol. In 1959 Bohm and Aharonov discovered the Aharonov–Bohm effect, showing how a magnetic field could affect a region of space in which the field had been shielded, although its vector potential did not vanish there. This showed for the first time that the magnetic vector potential, hitherto a mathematical convenience, could have real physical (quantum) effects. In 1961 Bohm was made Professor of Theoretical Physics at the University of London's Birkbeck College, becoming emeritus in 1987. His collected papers are stored there.

Implicate and explicate order

At Birkbeck College, much of the work of Bohm and Basil Hiley expanded on the notion of implicate, explicate and generative orders proposed by Bohm. In the view of Bohm and Hiley, "things, such as particles, objects, and indeed subjects" exist as "semi-autonomous quasi-local features" of an underlying activity. These features can be considered to be independent only up to a certain level of approximation in which certain criteria are fulfilled. In this picture, the classical limit for quantum phenomena, in terms of a condition that the action function is not much greater than Planck's constant, indicates one such criterion. They used the word "holomovement" for the activity in such orders.

Holonomic model of the brain

In a holographic reconstruction, each region of a photographic plate contains the whole image.

In collaboration with Stanford neuroscientist Karl Pribram, Bohm was involved in the early development of the holonomic model of the functioning of the brain, a model for human cognition that is drastically different from conventionally accepted ideas. Bohm worked with Pribram on the theory that the brain operates in a manner similar to a hologram, in accordance with quantum mathematical principles and the characteristics of wave patterns.

Thought as a System

Bohm was alarmed by what he considered an increasing imbalance of not only man and nature, but among peoples, as well as within people, themselves. Bohm mused: "So one begins to wonder what is going to happen to the human race. Technology keeps on advancing with greater and greater power, either for good or for destruction." He went on to ask:

What is the source of all this trouble? I'm saying that the source is basically in thought. Many people would think that such a statement is crazy, because thought is the one thing we have with which to solve our problems. That's part of our tradition. Yet it looks as if the thing we use to solve our problems with is the source of our problems. It's like going to the doctor and having him make you ill. In fact, in 20% of medical cases we do apparently have that going on. But in the case of thought, it's far over 20%.

In Bohm's view:

...the general tacit assumption in thought is that it's just telling you the way things are and that it's not doing anything – that 'you' are inside there, deciding what to do with the info. But you don't decide what to do with the info. Thought runs you. Thought, however, gives false info that you are running it, that you are the one who controls thought. Whereas actually thought is the one which controls each one of us.

Thought is creating divisions out of itself and then saying that they are there naturally. This is another major feature of thought: Thought doesn't know it is doing something and then it struggles against what it is doing. It doesn't want to know that it is doing it. And thought struggles against the results, trying to avoid those unpleasant results while keeping on with that way of thinking. That is what I call "sustained incoherence".

Bohm thus proposed in his book Thought as a System a pervasive, systematic nature of thought:

What I mean by "thought" is the whole thing – thought, felt, the body, the whole society sharing thoughts – it's all one process. It is essential for me not to break that up, because it's all one process; somebody else's thoughts become my thoughts, and vice versa. Therefore it would be wrong and misleading to break it up into my thoughts, your thoughts, my feelings, these feelings, those feelings... I would say that thought makes what is often called in modern language a system. A system means a set of connected things or parts. But the way people commonly use the word nowadays it means something all of whose parts are mutually interdependent – not only for their mutual action, but for their meaning and for their existence. A corporation is organized as a system – it has this department, that department, that department. They don't have any meaning separately; they only can function together. And also the body is a system. Society is a system in some sense. And so on.

Similarly, thought is a system. That system not only includes thoughts, "felts" and feelings, but it includes the state of the body; it includes the whole of society – as thought is passing back and forth between people in a process by which thought evolved from ancient times. A system is constantly engaged in a process of development, change, evolution and structure changes...although there are certain features of the system which become relatively fixed. We call this the structure.... Thought has been constantly evolving and we can't say when that structure began. But with the growth of civilization it has developed a great deal. It was probably very simple thought before civilization, and now it has become very complex and ramified and has much more incoherence than before.

Now, I say that this system has a fault in it – a "systematic fault". It is not a fault here, there or here, but it is a fault that is all throughout the system. Can you picture that? It is everywhere and nowhere. You may say "I see a problem here, so I will bring my thoughts to bear on this problem". But "my" thought is part of the system. It has the same fault as the fault I'm trying to look at, or a similar fault.

Thought is constantly creating problems that way and then trying to solve them. But as it tries to solve them it makes it worse because it doesn’t notice that it's creating them, and the more it thinks, the more problems it creates. (pp. 18–19)

Bohm viewed physical processes as determined by interacting levels of information of increasing subtlety, and did not limit this consideration to matter alone. In a 1990 article, "A new theory of the relationship of mind and matter", he resumed his view that there is a close link to mental processes: "the whole notion of active information suggests a rudimentary mind-like behaviour of matter". In his view, mental processes can also be understood as representing levels of activity of increasing subtlety that act upon each other. While everyday experience shows that thought is intricately connected to physical reactions, action as response to information need not be immediate; rather, in some cases at least, it can be mediated by "suspension" of physical action and the resulting train of thought.

Bohm suggested that the mental and the physical, which he saw as two "poles" of a unified whole, are closely interlinked and that "at each level, information is the bridge or link between the two sides". A relationship between the mental and matter may exist at indefinitely great levels of subtlety, while nonetheless each kind and level of mind may have a relative autonomy and stability. His article concludes with the statement that "knowledge of matter (as well as of mind) has changed in such a way as to support the approach that has been described here. To pursue this approach further might perhaps enable us to extend our knowledge of both poles into new domains".

Further interests

In his book On Creativity, quoting the work of Alfred Korzybski, Bohm expressed the view that "metaphysics is an expression of a world view" and is "thus to be regarded as an art form, resembling poetry in some ways and mathematics in others, rather than as an attempt to say something true about reality as a whole."

Bohm was keenly aware of various ideas outside the scientific mainstream. In his book Science, Order and Creativity, Bohm referred to the views of various biologists on the evolution of the species, including Rupert Sheldrake. He also knew the ideas of Wilhelm Reich.

Contrary to many other scientists, Bohm did not a priori exclude the paranormal. Bohm temporarily even held Uri Geller's bending of keys and spoons to be possible, prompting warning remarks by his colleague Basil Hiley that this might undermine the scientific credibility of their work in physics. Martin Gardner reported this in a Skeptical Inquirer article, and also critiqued the views of Krishnamurti, whom Bohm had encountered in 1959 and had many subsequent exchanges with. Gardner said that Bohm's view of the interconnectedness of mind and matter (on one occasion summarized as "Even the electron is informed with a certain level of mind") "flirted with panpsychism".

Bohm dialogue

To address societal problems during his later years, Bohm wrote a proposal for a solution that has become known as "Bohm Dialogue", in which equal status and "free space" form the most important prerequisites of communication and the appreciation of differing personal beliefs. An essential ingredient in this form of dialogue is that participants "suspend" immediate action or judgment and give themselves and each other the opportunity to become aware of the thought process itself. Bohm suggested that if these "dialogue groups" were experienced on a sufficiently wide scale, they could help overcome the isolation and fragmentation Bohm observed in society.

Later years

Bohm continued his work in quantum physics past his retirement in 1987. His final work, the posthumously published The Undivided Universe: An Ontological Interpretation of Quantum Theory (1993), resulted from a decades-long collaboration with Basil Hiley. He also spoke to audiences across Europe and North America on the importance of dialogue as a form of sociotherapy, a concept he borrowed from London psychiatrist and practitioner of Group Analysis Patrick De Mare, and had a series of meetings with the Dalai Lama. He was elected Fellow of the Royal Society in 1990.

Near the end of his life, Bohm began to experience a recurrence of the depression he had suffered earlier in life. He was admitted to the Maudsley Hospital in South London on 10 May 1991. His condition worsened and it was decided that the only treatment that might help him was electroconvulsive therapy. Bohm's wife consulted psychiatrist David Shainberg, Bohm's longtime friend and collaborator, who agreed that electroconvulsive treatments were probably his only option. Bohm showed improvement from the treatments and was released on 29 August. But his depression returned and was treated with medication.

Bohm died after suffering a heart attack in Hendon, London, on 27 October 1992, aged 74. He had been traveling in a London taxicab on that day; after getting no response from the passenger in the back seat for a few seconds, the driver found that Bohm had collapsed.

• 1951. Quantum Theory, New York: Prentice Hall. 1989 reprint, New York: Dover, ISBN 0-486-65969-0
• 1957. Causality and Chance in Modern Physics, 1961 Harper edition reprinted in 1980 by Philadelphia: U of Pennsylvania Press, ISBN 0-8122-1002-6
• 1962. Quanta and Reality, A Symposium, with N. R. Hanson and Mary B. Hesse, from a BBC program published by the American Research Council
• 1965. The Special Theory of Relativity, New York: W.A. Benjamin.
• 1980. Wholeness and the Implicate Order, London: Routledge, ISBN 0-7100-0971-2, 1983 Ark paperback: ISBN 0-7448-0000-5, 2002 paperback: ISBN 0-415-28979-3
• 1985. Unfolding Meaning: A weekend of dialogue with David Bohm (Donald Factor, editor), Gloucestershire: Foundation House, ISBN 0-948325-00-3, 1987 Ark paperback: ISBN 0-7448-0064-1, 1996 Routledge paperback: ISBN 0-415-13638-5
• 1985. The Ending of Time, with Jiddu Krishnamurti, San Francisco: Harper, ISBN 0-06-064796-5.
• 1987. Science, Order, and Creativity, with F. David Peat. London: Routledge. 2nd ed. 2000. ISBN 0-415-17182-2.
• 1989. Meaning And Information, In: P. Pylkkänen (ed.): The Search for Meaning: The New Spirit in Science and Philosophy, Crucible, The Aquarian Press, 1989, ISBN 978-1-85274-061-0.
• 1991. Changing Consciousness: Exploring the Hidden Source of the Social, Political and Environmental Crises Facing our World (a dialogue of words and images), coauthor Mark Edwards, Harper San Francisco, ISBN 0-06-250072-4
• 1992. Thought as a System (transcript of seminar held in Ojai, California, from 30 November to 2 December 1990), London: Routledge. ISBN 0-415-11980-4.
• 1993. The Undivided Universe: An ontological interpretation of quantum theory, with B.J. Hiley, London: Routledge, ISBN 0-415-12185-X (final work)
• 1996. On Dialogue. editor Lee Nichol. London: Routledge, hardcover: ISBN 0-415-14911-8, paperback: ISBN 0-415-14912-6, 2004 edition: ISBN 0-415-33641-4
• 1998. On Creativity, editor Lee Nichol. London: Routledge, hardcover: ISBN 0-415-17395-7, paperback: ISBN 0-415-17396-5, 2004 edition: ISBN 0-415-33640-6
• 1999. Limits of Thought: Discussions, with Jiddu Krishnamurti, London: Routledge, ISBN 0-415-19398-2.
• 1999. Bohm–Biederman Correspondence: Creativity and Science, with Charles Biederman. editor Paavo Pylkkänen. ISBN 0-415-16225-4.
• 2002. The Essential David Bohm. editor Lee Nichol. London: Routledge, ISBN 0-415-26174-0. preface by the Dalai Lama