# RUSSELL HANSON, DAVID BOHM AND OTHERS ON THE SEMANTICS OF DISCOVERY

## BOOK VII - Page 1

**
N**orwood
Russell Hanson (1924-1967), born in New Jersey, was
a U.S. Marine Corps fighter pilot during the Second
World War, who earned the rank of major, and was
awarded the Distinguished Flying Cross and the Air
Medal for flying combat missions over Japan.
Afterward he studied at the University of Chicago,
Columbia University, and Yale University in the
United States, and then studied at both Oxford
University and Cambridge University in England. He
received a Ph.D. from Oxford in 1955 and a Ph.D.
from Cambridge in 1956, and was afterward a fellow
at the Institute for Advanced Study at Princeton.
He accepted a faculty appointment at Indiana
University in 1957, where he was founder and
chairman of Indiana University's Department of
History and Logic of Science from 1960 to 1963. He
then accepted a professorship on the philosophy
department faculty of Yale University, which he had
at the time of his premature death at the age of
forty three in a crash of his private airplane in
1967. His principal works are *Patterns of
Discovery* (1958) and *Concept of the Positron
*(1963). At the time of his death he left an
uncompleted textbook in philosophy of science
intended for first-year college students, which was
edited by Willard C. Humphreys, a former student of
Hanson, and then published as *Perception and
Discovery* (1969). A year after his death a
complete bibliography of his publications appeared
in a memorial volume of *Boston Studies in the
Philosophy of Science*, Volume III (1968).

David Bohm (1917-1992) was born in Wilkes-Barre, PA,
and received his doctorate in physics from the University of
California. He taught physics at Princeton, and eventually
moved to England. He was professor of theoretical physics from
1961 at Birkbeck College, University of London, where he was
professor emeritus from 1983 until his death in 1992. A brief
biography may be found in the "General Introduction" in *
Quantum Implications* (ed. B.J. Hiley and F. David Peat,
1987), and a three-hundred-fifty page biography by David Peat
was later published under the title *Infinite Potential: The
Life and Times of David Bohm* (1997). Bohm’s initial
statement of his hidden-variable interpretation of quantum
theory was published in 1952 in two articles in the *Physical
Review*, in which he reports that the interpretation was
originally stimulated by a discussion with Einstein in 1951. His
principal statements of his hidden-variable interpretation of
quantum theory are set forth in two of his books. The earlier
is a brief monograph of only one-hundred-forty pages titled*
Causality and Chance in Modern Physics *published in 1957,
and the more recent is his more elaborate *Undivided Universe*
co-authored with Basil Hiley and posthumously published in 1993.
After publishing his seminal articles in 1952, he found that his
interpretation had been anticipated in important respects in
1927 by Louis de Broglie (1892-1987). De Broglie's
interpretation had been criticized severely, and he had
consequently abandoned it, but Bohm had further developed the
thesis enough that the fundamental objections confronting de
Broglie had been answered. Bohm's interpretation was shown to
be consistent with all the experimentally detectable effects
then known about of the quantum phenomena, and additional
suggestions were made by Vigier, a colleague of de Broglie. De
Broglie then returned to his original proposals, since he
believed that the decisive objections against them had been
answered. Bohm and Vigier afterwards published a joint paper
setting forth the interpretation in the *Physical Review *
in 1954, and de Broglie wrote a "Foreword" to Bohm's 1957 book.
Bohm was one of the physicists who recognized nonlocality
(a.k.a. entanglement) in the quantum theory. Peat’s generally
sympathetic biography shows how the idea of nonlocality led Bohm
firstly to his wholistic ontology for physics, then to his
process metaphysics, and finally to his mysticism of the
implicate order, according to which mind and matter are
indivisibly united. To the dismay and consternation of his
friends and colleagues, this mysticism was encouraged by Bohm’s
long-time association with an Indian guru, and also led Bohm to
take seriously the mind-over-matter exhibitions of a stage
magician.

Hanson takes very seriously issues about the
interpretation of the modern quantum theory, and he truculently
defends the Copenhagen interpretation. In “Appendix II” to his*
Patterns of Discovery *he notes that while for most practical
microphysical problems Born, who accepted the Copenhagen
interpretation, and Schrödinger, who did not, would have made
the same theoretical calculations. Nevertheless, their
alternative interpretations organized their thinking
differently, and consequently influenced their future research
work in very different ways. After 1930 Born was led to work on
collision behavior, on the statistical analysis of scattering
matrices, while Schrödinger pursued investigation of the
so-called ghost waves of the elementary particles. The
interpretations, therefore, are important because each supplies
an agenda that influences the direction of future research in
physics.

But Hanson does not view all interpretations as equally worthy of consideration, and he considers particularly unfortunate is the "hidden-variable" interpretation developed by David Bohm. In contrast to the Copenhagen interpretation with its duality thesis that the wave and particle are two manifestations of the same physical entity, Bohm’s alternative interpretation is that the wave and particle are different physical entities, even though they are never found separately. Furthermore it says that the wave oscillates in an as yet experimentally undetected and therefore hidden subquantum field. In the context of the topic of scientific discovery Bohm’s views are interesting, because they illustrate the semantical approach to scientific discovery and to the development of theory in physics. His views illustrate the use of linguistic figures of speech as a technique for theory development based on certain postulated basic similarities between the macrophysical and microphysical orders of magnitude, similarities that are denied by advocates of the Copenhagen interpretation. But firstly consider Bohm’s early advocacy of the Copenhagen interpretation, and then turn to his later agenda for future physics including his hidden-variable alternative to the Copenhagen interpretation for quantum theory.

**
Bohm's Early Copenhagen Views**

The hidden-variable thesis is Bohm’s more mature
view. He started out as an advocate of the Copenhagen
interpretation, which he also calls the “usual” interpretation,
and then changed his mind after the talk with Einstein in 1951,
the year in which his textbook titled *Quantum Theory* was
published setting forth his earlier view. There are at least two
noteworthy features of this early book. The first is Bohm’s
distorted understanding of Bohr’s philosophy of quantum theory.
The second is his ontology for quantum theory, the ontology of
potentialities, which anticipated Heisenberg’s similar ontology
of *potentia* by seven years.

In the “Preface” to his *Quantum Theory *Bohm
says that as a result of the work of Neils Bohr, it has become
possible to express the results of quantum theory in terms of
comparatively qualitative and imaginative concepts, which are
totally different from those appearing in the classical theory.
He rejects the view that the quantum properties of matter imply
the renunciation of the possibility of these properties being
understood in the customary imaginative sense, and that they
imply the sufficiency of only a self-consistent mathematical
formalism which can in some mysterious way correctly predict the
numerical results of experiments. The eighth chapter of the
book is titled “An Attempt to Build a Physical Picture of the
Quantum Nature of Matter”, and Bohm writes in a footnote that
many of the ideas appearing in the chapter are an elaboration of
material in Bohr’s *Atomic Theory and the Description of
Matter*. However, Bohm’s understanding of Bohr is
distorted. Bohr maintained an instrumentalist view of the
equations of quantum theory, which rejects any semantics or
ontology for quantum theory, and he repeatedly denied explicitly
that quantum phenomena are pictureable. From Bohm’s statement in
his 1952 articles that his hidden-variables thesis was the
result of a talk with Einstein in 1951, it is reasonable to
speculate that Einstein had read Bohm’s book, had recognized
that Bohm was ripe for disillusionment with the views in Bohr’s
philosophy, and had concluded that Bohm was ready for induction
into the ranks of Bohr’s critics. In any event whatever may
have been Einstein’s unreported comments to Bohm in their
private conversation, the ultimate outcome after forty years was
Bohm’s *Undivided Universe: An Ontological Interpretation of
Quantum Theory* (1973), a book in which Bohm explicitly says
he is supplying an ontology to replace the epistemological
interpretation he thought he had found in Bohr’s writings.

The ontology for quantum theory that Bohm described in 1951 is a wholistic ontology of potentialities, in which the world is an indivisible unit where quanta have no component parts describable by hidden variables, and are not even separate objects, but are only a way of talking about indivisible transitions. This metaphysics is also called monism. At the quantum-mechanical level the properties of a given object do not exist separately in the quantum object alone, but rather are potentialities which are realized in a way that depends on the systems with which the object interacts. Thus the electron has the potentiality for developing either its particle-like or its wave-like form, depending on whether it interacts with an apparatus that measures either its position or momentum. Bohm’s views are also realist; he does not maintain that the quantum phenomenon has its properties because it is being measured. He says that a quantum-mechanical system can produce classically describable effects not only in a measuring apparatus, but also in all kinds of systems that are not actually being used for the purpose of making measurements. Throughout the process of measurement the potentialities of the electron change in a continuous way, while the forms in which these potentialities can be realized are discrete. The continuously changing potentialities and the discontinuous forms in which the potentialities may be realized are complementary properties of the electron.

Bohm anticipated Heisenberg’s idea of potentiality,
which Heisenberg did not propose until his *Physics and
Philosophy* in 1958, the only place in Heisenberg’s literary
corpus where the idea is mentioned. But there are differences in
their ideas of potentiality, because unlike Bohm’s, Heisenberg’s
is not a wholistic version. In the 1951 book Bohm said that
potentiality makes quantum theory inconsistent with the
hidden-variables thesis, because the hidden-variables view is
based on the incorrect assumption that there are separately
existing and precisely defined elements of reality. The idea of
potentiality is much more integral to Bohm’s earlier
interpretation than to Heisenberg’s, and it had distinctive
implications for Bohm. One implication is Bohm’s thesis that
mathematics is inadequate for physics. He says that the
interpretation of the properties of the electron as incompletely
defined potentialities finds its mathematical reflection in the
fact that the wave function does not completely determine its
own interpretation until it interacts with the measuring device,
and that the wave function is not in one-to-one correspondence
with the actual behavior of matter, but is merely an abstraction
reflecting only certain aspects of reality. He believes that to
obtain a description of all aspects of the world, one must
supplement the mathematical description with a physical
interpretation in terms of the incompletely defined
potentialities.

Shortly afterwards he accepted the hidden-variables
idea, and in the second chapter of his *Undivided Universe*,
where he mentions in a footnote his anticipation of Heisenberg’s
idea of potentiality, he rejects altogether the potentiality
thesis that the particle itself is created by the measurement
process. In Bohm’s hidden-variables view, the particle is not a
wave-packet or otherwise created out of the wave; the particle
is in reality distinct from the wave. His later view is not
wave *or* particle, but wave *and* particle. That is,
the wave and particle are not two alternative aspects of the
same entity, but are different and separate entities.

**
Bohm's Agenda for Future Microphysics**

Bohm's hidden-variable interpretation is an agenda for
future microphysics, and his *Causality and Chance* (1957)
sets forth three related objectives in this agenda. His *
first objective* is the relatively modest one of
demonstrating that an alternative to the Copenhagen
interpretation is possible, in the sense that it is not the only
one that is consistent with the formalism and measurements of
quantum theory. He states this objective not only because he
has another interpretation in mind, but also because he
maintains that the development of alternative views is important
for the advancement of science, while advocates of the
Copenhagen interpretation deny that any alternative view
including one involving a subquantum order of magnitude is
conceivable. For example in his "Questions of Principle in
Modern Physics" (1935) in *Philosophical Problems of Quantum
Physics* Heisenberg states that the indeterminacy principle
must be taken as a question of principle making other
formulations into false and meaningless questions, just as in
relativity theory it is supposed that it is in principle
impossible to transmit signals at speeds greater than the
velocity of light. But Bohm maintains that without alternatives
the physicist is constrained to work along accepted lines of
thought in the hope that either new experimental developments or
new theoretical insights will eventually lead to a new theory.
Bohm maintains that one of the functions of criticism in physics
is to suggest alternative lines of research that are likely to
lead in a productive direction. He thus sees criticism with
alternatives to be integral to scientific discovery. This
objective is particularly attractive to the philosopher of
science Paul Feyerabend, once an advocate of Bohm's
interpretation, who to the end of his life maintained that
creating alternatives is necessary for advancement.

Bohm's *second objective* is to propose an
interpretation of the history of physics, which shows successful
precedents for the research strategy represented by his
hidden-variable interpretation of quantum theory. The
paradigmatic precedent he invokes is the atomic theory of
matter, which postulated the existence of atoms unobservable at
the time the theory was proposed. Analogously Bohm’s strategy
consists of postulating that there exists an order of physical
magnitude below the quantum order of magnitude containing the
quantum of action represented by Planck's constant. Bohm
postulates that this subquantum order contains qualitatively
different types of phenomena governed by more deterministic laws
than do those known to exist at the quantum order of magnitude.
The existence of this postulated subquantum order of
microphysical phenomena is denied by the Copenhagen
interpretation advocates, and since there was no experimental
detection of any such subquantum phenomena, the theory that
postulates them is said to have “hidden variables”.

Bohm opposes his historical interpretation to another that he calls “mechanistic”, a term that is unfortunately ambiguous in both philosophical and scientific usage, but which has a specific and somewhat elaborate meaning in Bohm’s book. According to the objectionable mechanistic philosophy opposed by Bohm the qualitative diversity of things in the world can be reduced completely, without approximation, and in every possible domain of science to nothing more than the effects of some definite and limited general framework of quantitative laws, which are regarded as absolute and final. Prior to the development of quantum theory these quantitative laws were assumed to be deterministic; then later with the development of the Copenhagen interpretation of quantum theory these laws were assumed to be nondeterministic. Hence there are both deterministic and nondeterministic varieties of mechanism. In the former variety causal laws are thought to be fundamental, while in the latter probability laws are thought to be fundamental. Nondeterministic mechanism prevails today, because physicists have accepted Heisenberg's thesis that the indeterminacy principle represents an absolute and final limitation on our ability ever to define the state of things by measurement.

In *Causality and Chance* Bohm maintains that
causality and chance are both fundamental and objective, and
that both determinism and nondeterminism are merely
idealizations. Thus he rejects Einstein's determinism. He also
rejects the subjective interpretation of probability, which says
that the appearance of chance is a result of human ignorance.
And he rejects the idea common to both deterministic and
nondeterministic varieties of mechanism that there is only one
general framework of laws and a limited qualitative diversity.
Bohm maintains that there are different orders of magnitude with
each level having its own laws and qualitative diversity. In
the history of physics revolutionary developments have occurred
when laws and qualities at a higher level are explained by those
of a lower level. Experiments may disclose a breakdown of an
entire scheme of laws by the appearance of chance fluctuations
not originating in anything at the higher level, but instead
originating in qualitatively different kinds of factors at a
lower level. For example in classical physics a particle such
as an electron follows the classical orbit only approximately,
while in a more accurate treatment it is found to undergo random
fluctuations in its motions arising outside the context of the
classical level. Thus Bohm affirms by way of historical analogy
and on the basis of his nonmechanistic interpretation of the
history of science that there is a deeper subquantum order of
magnitude, which in turn explains the randomness that is
detected at the higher quantum order of magnitude.

Bohm’s hidden-variable interpretation is both an alternative interpretation of quantum theory motivated by this prior ontological commitment to a subquantum order and also by a discovery heuristic for which there is historical precedent. He maintains that new work is considerably facilitated by his thesis of a hidden subquantum order, because the physicist can imagine what is happening, and can thereby be led to new ideas not only by looking directly for new equations but also by a related procedure of thinking in terms of concepts and models that will help to suggest new equations that would not likely be suggested by mathematics alone. And he uses his postulated subquantum ontology as a basis for linguistic figures of speech such as analogy, which are a central feature in his discovery strategy. These figures of speech aid in formulating new hypotheses for future physics both on the basis of similarities between the macrophysical and microphysical orders of magnitude and on the basis of past developments in the history of physics, which he believes justifies his hidden-variables ontology.

Bohm's *third objective* is to use the
hidden-variable interpretation as a guide for future research
for a new microphysical theory that will resolve what he sees as
the current crisis in quantum physics. This crisis manifests
itself in Dirac's relativistic quantum theory, when the wave
equation is applied to the description of particle scattering
with very high energies and at short distances. For the
Schrödinger wave equation to be used in such applications, an *
ad hoc* mathematical adjustment called “renormalization” is
necessary. Furthermore the behavior of very high-energy
particles in experiments reveals that there exist many new kinds
of particles not previously known, and that they are unstable,
since they decay into one another and create other particles.
Nothing like this is accounted for by current quantum theory.
To Bohm these problems for the current quantum theory suggest
that elementary particles are not really elementary. The concept
of a subquantum level justifies the physicist considering a
whole range of qualitatively new kinds of theories that approach
the currently accepted theory only as approximations that hold
in limiting cases. He believes that the current crisis in
quantum theory portends a revolution in microphysics, and that
his hidden-variable interpretation offers a superior guide for
research that promises to resolve the crisis.

In summary these three objectives of Bohm's agenda
represent successively more ambitious claims. The first claim
is merely that an alternative to the Copenhagen semantical
interpretation describing a subquantum level of magnitude is
conceivable in the sense that it is consistent with the data and
formalism of the current quantum theory. The second claim
states more ambitiously that the history of physics reveals that
postulating lower levels of magnitude supplies an analogy, which
is a productive strategy to guide new research. The third claim
is still more ambitious; it states that a new scientific
revolution in microphysics is at hand, and that the
hidden-variable semantical interpretation will produce a new
microphysical theory that will resolve the current crisis in
quantum theory. As de Broglie said in the closing sentence of
his "Foreword" to *Causality and Chance* (1957), Bohm's
book comes at exactly the right time. Thirty-five years later
in his *Undivided Universe* Bohm was still predicting this
impending revolution. More recent experiments based on John
Stuart Bell’s inequality have occasioned reconsideration of the
merits of Bohmian mechanics. But if there has been any
revolution since those days, it has been the quite different
string theory.

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**NOTE: Pages do not corresponds
with the actual pages from the book**