Bohm’s Quantum Physics Recognised at Last
Many theosophists will know of Bohm as a close associate of Krishnamurti, and also as a unique philosopher. However his primary role was as a quantum physicist. He had a unique realistic interpretation of quantum physics (see below) which was either rejected or ignored by virtually the entire physics community from 1952 when he first developed his approach until his death in 1992. I surmised at the time that perhaps he might be appreciated in the new century although I was not optimistic.
Indeed there has been a revival of what is now being referred to as Bohmian Mechanics, including emphasis on REALITY as distinct from the unreality of the traditional approach of Bohr, emphasizing the “Unreality” of whatever happens in a quantum experiment prior to the resulting observation. There is a feature article on “Bohmian Mechanics” in New Scientist for 22 March, 2008. Clearly what is being discussed is Bohm’s interpretation of quantum mechanics. On the cover of the issue, there is the word UNREALITY with UN shaded almost out. A search on the internet discloses a lengthy article on Bohmian mechanics from the Stanford Encyclopedia of Philosophy. This is a 2006 revision of an original article in 2001. Much of it is mathematically sophisticated.
Bohm was born at Wilkes Barre in Pennsylvania in 1917 and obtained his PhD under Oppenheimer at Berkeley in 1947. He then held various positions there until 1961 when he was appointed as an assistant professor at Princeton University. He had a number of discussions there with Einstein who was at the Institute of Advanced Studies. They agreed on their disapproval of Bohr’s concept of the nonreality of the quantum world prior to observation of the results of an experiment. However, they disagreed with what was then known as nonlocality (or distant interconnectedness) but is now often referred to as entanglement. Einstein referred to it as “spooky action at a distance”. For Bohm it is not only an essential feature of quantum physics but is also an integral part of his philosophy of universal interconnectedness
While at Princeton, Bohm was called to appear before the Un-American Activities Committee of parliament to testify against Oppenheimer and others. It was a time of paranoia in America about communism. The Committee chaired by the infamous Senator McCarthy behaved like an inquisition. Oppenheimer had been in charge of the atom bomb but refused to work on the hydrogen bomb on ethical grounds and was suspected of communist sympathies. Bohm refused to testify and he was indicted for Contempt of Congress. Although this indictment was subsequently withdrawn, he was ostracised and asked to stay away from the University. That gave him more time to concentrate on writing his book. However when he came up for reappointment, his position was terminated and, in the climate of the day, he was unable to obtain a position anywhere in America. However, he obtained a professorship at the University of Sao Paulo in Brazil from 1951 to 1955. He then took up a position for two years at Haifa in Israel where he married in 1956. The following year he obtained a Research Fellowship at Bristol, followed after a few years, by appointment as Professor of Theoretical Physics at Birkbeck College, University of London, where he spent the rest of his life. He retired in 1983, becoming Emeritus Professor, and died of a heart attack in 1992.
At Bristol, Bohm’s wife brought home a book which she thought might interest him as it talked about the observer and the observed… The book was by Krishnamurti: The First and Last Freedom and Bohm found its philosophy very interesting indeed and compatible with his. He contacted Krishnamurti and they become close associates. In due course Bohm became a member of the Krishnamurti Foundation. They had many discussions on matters of common interest relevant to Bohm’s unique philosophy of wholeness which were recorded on tape, sometimes including also other participants. Dr. Geoffrey Miller at Springbrook accumulated a complete set of the tapes and they are preserved at the library of the Springbrook Theosophical Retreat Centre.
Bohmian Mechanics — The New Scientist Article
The New Scientist article is headed “Quantum Randomness may not be random,” an extract says: “The mainstream view is that uncertainty is a fundamental feature of everything … and quantum researchers celebrate the notion that pure chance lies at the foundation of the universe. However, a sizable minority of physicists … remain unconvinced that quantum theory depends on pure chance and they shun the philosophical contortions of quantum weirdness. The world is not inherently random they say. It only appears that way. ”Sheldon Goldstein of Rutgers University in New Jersey and other like minded physicists have been pursuing an alternative quantum theory known as Bohmian Mechanics in which particles follow precise trajectories through space and time. “It’s a reformulation of quantum theory which is not at all congenial to supposedly deep quantum philosophy’ says Goldstein. ‘It’s precise and objective,” It is clear that what is being discussed is Bohm’s version of quantum mechanics. (See below).
The fundamentals of quantum physics are usually discussed, as here, in terms of an experiment where a series of fundamental particles such as electrons is sent through an apparatus with two closely spaced parallel slits, toward a detecting screen which records a typical “interference pattern” with a central peak image of a slit and lesser peaks (with gaps between) tapering off in intensity on either side. “While mainstream quantum theory insists that you can’t give any account of how each particle moves, Bohmian mechanics can,” thus replacing the fuzziness of the standard theory according to Bohr with certainty. “The wave function choreographs the motion of the particles”. [Note: An extreme view of Bohr even contends that the pattern on the screen only becomes real when observed. Bohr has been cited as saying “There is no quantum world; only a quantum mechanical description.”]
There is acknowledgement of just one area, (of no great consequence), where standard Bohmian mechanics does not work; i.e. at ultra high speeds necessitating the use of special relativity. However, the article reports that, during the last decade, Goldstein and others at the University of Genoa have developed Bohmian models giving a consistent view of relativistic particle processes while mirroring the accurate predictions of quantum field theory. The main objections have now either been addressed, turned out not to be serious, or shown to also represent the same problems for the standard theory.
Even so most physicists are not willing to adopt the new models because they don’t make any predictions which differ from the standard model. Thus ideological objections rather than technical concerns have been mainly responsible for reluctance to adopt new models such as that of Bohm. Surely the realism of Bohm’s approach should win out over the unreality of the standard Copenhagen approach of Bohr. The final statement of the article is that “according to the Bohm theory, uncertainty arises from the interactions between the measuring device and the particle. It is not inherent in the universe”.
The Birth (and early struggles) of what is now called Bohmian Mechanics
At Princeton Bohm lectured on Quantum Mechanics and wrote a book on it from Bohr’s traditional point of view to help himself understand it. This book was long regarded as a classic. However, having written the book, Bohm was dissatisfied. He was soon, however, to publish his own very different interpretation.
In 1952 (while in Brazil), he published in an important theoretical physics journal, papers developing a mathematical modification to the fundamental equation of quantum physics, the Schrodinger equation. This produced a term that he called the quantum potential which took account of the instantaneous effect on the particles of the surroundings, It was this work which work enabled him to calculate the actual paths of the particles in the double slit experiment discussed in the New Scientist article, in defiance of the claim according the so called “Copenhagen” interpretation of Neils Bohr of their ‘unreality’. In the strict Copenhagen view, nothing is real until the pattern on the screen is observed.
In his later work he refers to the quantum potential as a “quantum information potential”. A particle is influenced by its surroundings through the “quantum information potential”. Its influence is immediate and does not necessarily fall off with distance, as do typical physical influences. This is a much more subtle effect than is allowed in the standard theory. It provides what Bohm refers to as “active information” about the surroundings. As an aid to understanding the concept of active information, he uses an approximate analogy of a ship in a fog using radar to avoid obstacles. The return radar signal gives information about the surroundings to enable the ship to avoid the obstacles but the radar does not drive the ship. The signal is “active” insofar as the information it provides about the surroundings affects the course of the ship, but it is the ship’s engines which actually drive the ship.
The concept of such a ‘pilot wave’ as an explanation of quantum mechanics had been flirted with in 1927 by Louis de Broglie but he quickly discarded it following strong opposition. He is even sometimes clamed as the first proponent of Bohmian mechanics.
Bohm’s Battle for Recognition
Bohm’s work was ignored at the time or misrepresented and spurious reasons were found for rejecting it. However, in the early days of QM there was discussion of whether there might be some ‘hidden variable’ [read as ‘hidden. factor’] which could explain the puzzling implications of QM. Bohm at first cast his theory as a form of a ‘hidden variable theory’ and he became stuck with the epithet of ‘the hidden variables man’.
Prominent theoretical physicist, Von Neumann gave a mathematical proof that no ‘hidden variable’ theory could be consistent with the experimental predictions of quantum theory. The existence of von Neumann’s theorem was a major reason Bohm was not taken seriously by the main body of physicists. A more aggressive character than Bohm might have fought harder against the prejudice concerning his theory but that was not his style.
Von Neumann’s criticism was later refuted by an even more influential quantum theorist, and a major figure in the ongoing development of the theory, John Bell, who stated in relation to Bohm’s work, “I saw the impossible done.” He showed that certain of von Neumann’s assumptions were not valid, especially as applied to the type of theory espoused by Bohm. The whole concept of hidden variables has been one mighty great red herring as far as consideration of Bohm’s interpretation is concerned.
In 1964, Bell published an important theorem which proved that “No local hidden variable theory could be consistent with quantum physics”. In the introduction to that paper, Bell stated: “A hidden variable interpretation of elementary quantum theory has been constructed,” and gave a reference to Bohm’s 1952 paper. Bell went on to say “That particular interpretation has a grossly non-local structure [i.e. it incorporates entanglement].This is characteristic, according to the result to be proved here, of any such theory, which reproduces exactly the quantum mechanical predictions.” In other words Bell is both asserting the crucial importance of nonlocality, (entanglement) and supporting Bohm. Yet perversely, he was widely misinterpreted as condemning Bohm.
Bell went on the attack in paper after paper supporting Bohm, inventing some interesting and even amusing analogies, and producing a book: “Speakable and Unspeakable in Quantum Mechanics.” Instead of talking about ‘observables’ to describe physical quantities, Bell preferred to speak of what he called “be-ables”, thus emphasizing their physical reality. This is an important book. Bell regarded it as tragic that Bohm’s interpretation (now known as Bohmian mechanics) was not taught in university courses at least as a possible alternative explanation of quantum phenomena.
While Bohm was largely neglected, if not openly disbelieved, he did have some support, for example from Holland and Vigier of the Pierre and Marie Curie University in Paris. Peter Holland published in 1993 a very substantial tome The Quantum Theory of Motion, [Cambridge University Press], consisting largely of what would now be called Bohmian Mechanics. The same year Undivided Universe by Bohm and Hiley [Routledge, London] was published, largely on the same topic but with also some examples of philosophical thought. Both books are highly mathematical but Bohm, in particular includes some philosophical statements (for which I do not have room here). Bohm died suddenly of a heart attack in November 1992 just as the proof reading was completed, and Hiley saw the book through to publication. It is remarkable that two such comprehensive treatments of what is now known as Bohmian Mechanics should be published independently and concurrently. Could it be that that those two books became the impetus for the final recognition?
Prominent physicist, Henry Stapp, says on the back cover of the Bohm and Hiley book: “This book will, I believe, change the way quantum physics is taught,” Unfortunately, Bohm, after all his efforts, did not live to see that day.
The philosophical implications of entanglement are momentous. Entanglement was first verified experimentally over short distances by a subtle experiment in 1982 and has been extensively studied since. It means the distant objects can be connected instantaneously in subtle ways by subtle influences… No signaling is possible at greater than the speed of light. But more subtle distant interconnections are possible. Bohm was the first to seize on the wider implications and it permeates both his physics and his philosophy. Indeed the two are closely intertwined. Apply over and over again many times the subtle interconnection of a pair of distant objects and this ultimately leads to the subtle interconnection of everything at some deep level. This is the physical basis of Bohm’s concept of the holomovement or the implicate order, a higher level of order than everyday ‘explicate order’. It meshes very well with his interest in Krishnamurti’s philosophy. He also suggests the possibility of even higher levels of order — rather like the theosophical concept of higher planes but less mechanistic.
Bohm wrote numerous articles in scientific Journals, in common with his main collaborator, Basil Hiley and others; especially in Foundations of Physics, a Journal which specializes in fundamental conceptual issues. In 1975, Bohm and Hiley began one such article with the following statement:
- “What we are proposing is that we be ready to explore a new notion of physical reality, in which we start from unbroken wholeness of the totality of the universe….We have reversed the usual classical notion that the independent ‘elementary parts’ of the world are the fundamental reality and that the various systems are merely particular contingent forms and arrangements of these parts. Rather, we say that inseparable quantum interconnectedness of the whole universe is the fundamental reality and that relatively independently behaving parts are merely particular and contingent forms within the whole.
- Individual human beings may be considered as subsystems in a system consisting of a social group. Evidently the relationships of any two individual human beings depend crucially on the state of the immediate social group to which they belong, and ultimately on that of the larger social group. Similarly, the interactions of any two cells in the body depend on the state of the whole organ of which they are a part, and ultimately on the state of the organism as a whole…… In this way we see that there is accessible to us a very wide range of direct intuitive experience in the form of wholeness. What quantum theory as understood through [our] interpretation, shows is that this form is appropriate, not only biologically, socially, and psychologically, but also for understanding the laws of physics. And so we are able to comprehend the whole world in all its aspects through the one universal order of thought, thus removing an important source of fragmentation between physics and other aspects of life”. [emphasis mine]
This canvasses just one aspect of Bohm’s comprehensive philosophical thought. What I find remarkable is that it should be published in a Journal which typically publishes sophisticated articles on topics in theoretical physics.
There have been many eulogies for Bohm
Prominent physicist, Max Jammer says in an article celebrating Bohm’s 60th birthday: “Even those who do not share his point of view, admire the originality and independence of his thought, as well as the outstanding intellectual honesty and uncompromisability of his personality”.
Renee Webber (Lecturer in philosophy at Rutgers University, and incidentally a member of the Theosophical Society) who interviewed Bohm for her book Dialogues with Scientists and Sages says: “I was quite unprepared for the unusually modest and unassuming, gentle person he turned out to be”.
Robert Temple says in an article based on his interview with Bohm for New Scientist in 1982: “Bohm’s complete lack of ego or any air of importance completely disguises the enormity of his intellect”
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