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

BOOK VII - Page 9

Comment and Conclusion

          Contrary to often expressed opinion the topic of scientific discovery has not been a neglected one in philosophy of science.  The above survey reveals that many philosophers and scientists have addressed it with a semantical approach using linguistic figures of speech.  But no application of an explicit metatheory of scientific theory-development using a purely semantical approach has yet succeeded in generating a new and successful scientific theory in any contemporary science, even though noteworthy historic scientific discoveries have resulted from the intuitive use of such semantical devices as analogy and metaphor.  To date the only metatheories that are sufficiently practical to function as applicable procedures for scientific discovery are those based on mechanized discovery systems, and most of these have been academic exercises involving the reconstruction of existing or historical theories.  Only a few discovery systems have actually been used to develop new theories at the contemporary frontier of a science.  Due to his semantical views Hanson had not examined the use of figures of speech, and very few discovery systems existed before his death in 1967. 

          But in his examination of historical episodes in the history of science he recognized and documented cases in which semantics has operated as a constraint upon discovery, and he understood that this phenomenon implies the need for a reconsideration of the nature of scientific language, especially the language used for observational reporting.  However, he never got beyond gestalt psychology, and had only suggested a metatheory of semantical description in his discussion of the semantics of Newton’s mechanics.

          The following commentary is divided into five topics: (1) Firstly Hanson's attempt at a logic of discovery with his wholistic gestalt semantics is critiqued. (2) Secondly Hanson’s defense of the Copenhagen interpretation with its duality thesis is considered in the context of semantical change in science. (3) Thirdly Hanson’s principal criticism of Bohm's hidden-variable thesis is viewed in retrospect. (4) Fourthly some comments are given on Bohm's and Hesse’s use of metaphor, and Wittgenstein’s family-resemblance theory of meaning is critiqued. (5) And finally a new semantical metatheory of analogy, metaphor, and simile is set forth.

          (1) Consider firstly Hanson’s proposed logic of scientific discovery, which took as its point of departure Peirce’s investigations.  Peirce’s abductive (a.k.a. retroductive) logic of discovery does not conclude to a unique theory from a given set of premises as deductive logic concludes to a unique theorem.  And Hanson does not propose that there exists a resolution for this logical inconclusiveness, much less does he supply one.  But Hanson adds something to Peirce, namely the controlling role of logical syntax in the determination of semantics, which in turn strongly influences the selection of candidate hypotheses available for abduction.  Thus he says that the mathematical formalism or syntax of the empirically adequate quantum theory defines the conceptual possibilities for any future development of microphysical theory, while paradoxically he also maintains that it offers a conceptual resistance to any future development of an alternative microphysical theory having a different formalism. This controlling role for syntactical structure governing semantics in statements and equations accepted as true implies an artifactual thesis of the semantics of language.  But in spite of the importance that Hanson places on semantics, he never used or developed a systematic philosophy of language.  His principal inspiration was Wittgenstein's Investigations, which is not without its insights, but is an aphoristic approach to philosophy of language.  In his discussion of "seeing" Wittgenstein employed ambiguous drawings such as are commonly used in texts on gestalt psychology, and Hanson developed a semantics of language based on the idea of the conceptual gestalt.  Unfortunately gestalt psychology is a very blunt instrument for semantical analysis, because it is wholistic.

          Hanson's philosophy of scientific discovery was greatly influenced by the physicist Paul Dirac.  Dirac had told Hanson that the Copenhagen interpretation figured essentially in his development of the formalism of his relativistic quantum theory.  Hanson therefore took the position that the Copenhagen interpretation (without Bohr's naïve epistemology based on forms of perception) is that one, unique, and distinctive semantical interpretation supplied by the formalism itself, and is not merely some philosophical idea appended to the formalism.  However, the gestalt semantics is not adequate to the defense of Hanson's view of that Copenhagen interpretation is integral to the formalism of the modern quantum theory.  Had Dirac said just the opposite of what Hanson reports he said about the Copenhagen interpretation's relation to the formalism of quantum theory, then the gestalt semantics would have been neither more nor less serviceable for a semantical analysis of quantum theory.  This is because the conceptual gestalt is wholistic and does not enable the philosopher of science to separate or even distinguish the semantics that may in some way be integral to the quantum theory's formalism, from that which may not be integral to the formalism but is merely appended to the formalism – what Hanson calls mere philosophy and Bohm calls informal language.  In fact Hanson's gestalt semantics does not even offer him a basis for his distinction between the Copenhagen interpretation and the Bohr interpretation.  The wholistic character of the conceptual gestalt makes it impossible to partition the semantics of the quantum theory into parts, to identify those parts that are integral to the formalism and those parts that are not, or those parts that are properly called the Copenhagen interpretation and those parts that are distinctive to the Bohr interpretation.  In Patterns of Discovery Hanson had a brief flirtation with the idea that the meanings of terms contain each other as parts, but he failed to explore the idea.  Had he done so, he would have found that semantics can be as analyzable as the syntax of any semantically interpreted and empirically warranted text.

          The wholistic character of the conceptual gestalt also thwarts Hanson's attempt to explain scientific discovery.  On the one hand the conceptual gestalt offers conceptual resistance to any change to a new gestalt and therefore to any new theory.  In other words it is an impediment to the semantical change integral to scientific discovery.  On the other hand it is also a guide to scientific discovery, because it informs the scientist of the kind of hypothesis that may satisfy the retroductive logic of scientific discovery.  Semantics may function in both of these contrary ways, but the gestalt psychology cannot explain how.  More specifically in connection with the modern quantum theory, the gestalt psychology does not explain why Hanson should be defending the Copenhagen interpretation as a guide instead of attacking it as an impediment to the discovery of a new and more empirically adequate quantum theory.  The reason for this problem is the basic fact that the wholistic gestalt cannot function in a logic of scientific discovery or in any other application of logic, because its wholistic character deprives retroductive logic of any procedural character.  Retroduction can only describe the conditions that the new gestalt must satisfy after it has been found, which is to say that it is a statement of a scientific problem that the discovery must solve rather than a procedure for obtaining a solution.

          On the gestalt view the discovery itself is a transition that does not admit to a procedure, just as the transition from one interpretation of an ambiguous drawing to another does not admit to a procedure.  Just as there could never be a logical or mathematical formalism to describe the transition occurring in a change of a substantial form described in Aristotle's physics, so too there could never be a logical formalism to describe the change in a change of a gestalt form in modern physics.  In both cases the transition from one form to the other is a substitution, which is instantaneous, whole and complete, and with no intelligible continuity to warrant calling it a processional transition instead of a simple replacement.

          (2) Consider secondly Hanson's defense of the Copenhagen interpretation and his view that the formalism of the equations and statements of the theory express it.  The central question is whether the semantics of physical theory is exhaustively specified by the equations of the theory together with the statements describing the measured phenomena, the measurement apparatus, and procedures used to obtain the measurement data related by the equations, or whether additional discourse is involved further characterizing the domain of the equations and measurements.  Hanson rejects any semantical role in scientific explanation for any discourse other than the equations of the theory and the statements required for experimental description and measurement procedures. Accordingly he maintained that duality, which is the distinctive characteristic of the Copenhagen interpretation, is not some semantics added to the formalism of the quantum theory by those statements that he called mere philosophy, but rather is an ontological claim expressed by the formalism due to the formalism’s control of the semantics of the theory.  His motive for stating this position is Dirac's statement made personally to Hanson that the wave-particle duality is integral to the formalism, and that it was strategic in Dirac’s development of his own relativistic quantum theory.  And duality is in fact integral to the syntax of Dirac’s operator calculus.

          But there are physicists who disagree with Hanson’s view.  Some disagree because they do not recognize the occurrence of semantical change.  Hanson illustrates the phenomenon of semantical change in the first chapter of his Concept of the Positron, where he gives a brief historical overview of the wave and particle theories of light.  He notes that Newton did not have a semantics for the terms “wave" and "particle" making the concepts dichotomous or mutually exclusive, when Newton proposed his theory of “fits”.  Only later did these con­cepts assume their dichotomous implications, when the experiments of Foucault, Frenzel, and Young were believed to have the force of crucial experiments that persuaded the physicist that they must decide between one and the other characterization.  Thus the concepts of wave and particle had undergone semantical change with the advance of physical experiment and theory.  By the twentieth century the wave-particle dichotomy had become well established even though the discoveries of Planck’s quantum of action in 1900, Einstein’s equation for the photoelectric effect for light in 1905, Compton’s equation for his Compton effect for x-rays in 1922, and de Broglie’s de Broglie’s equation for electron matter waves making the particle’s momentum p a function of the wave length λ and Planck’s constant h in 1924 enabled physicists to express duality mathematically prior to development of the modern quantum theory by Heisenberg and Schrödinger. Interestingly in his Conceptual Development of Quantum Mechanics (1966) Max Jammer observed that Bohr had come to his complementarity principle by consideration of these earlier equations, and he references a four-page postscript to a paper written by Bohr in 1925.  This is one year before Heisenberg reports that Bohr had developed his complementarity principle.

          Yet in spite of having been led by these considerations to conclude that wave and particle are alternative manifestations of the same physical entity, the inconsistent concepts were retained by Bohr, because he believed that one must retain the Newtonian concepts of wave and particle, on which he based his complementarity principle, and then relegated mathematical formalism to an instrumentalist status, even as he affirmed duality.  His complementarity principle is a contradiction resulting from his belief in the naturalistic philosophy of perception, which in turn implies that like all classical concepts, those of wave and particle, cannot be changed.  And the complementarity principle is an example of the philosophical discourse defining the semantics in a way that is inconsistent with the semantics defined by acceptance of the mathematically expressed quantum theory.  After some weeks of disagreement with Bohr, Heisenberg concluded that he could accommodate Bohr's complementarity thesis by accepting the idea that the wave-particle duality is expressed by the indeterminacy principle, save that the mathematical formalism of the indeterminacy principle is consistent while the complementarity principle is inconsistent.  Heisenberg made this accommodation, because Bohr persuaded him to accept a naturalistic philosophy of perception.  Yet in so doing, Heisenberg was philosophically inconsistent, since unlike Bohr, he did not construe the formalism instrumentally.  Instead by accepting Einstein’s admonition that the theory decides what the physicist can observe, Heisenberg let his theory decide what the physicist observes in the cloud chamber, and furthermore following Einstein's precedent applying scientific realism to the concept of time in relativity theory, Heisenberg likewise construed his indeterminacy relations realistically.

          The only way the Copenhagen duality thesis can be affirmed consistently is to let the equations control the semantics of the terms "wave" and "particle", as these terms relate to the descriptive variables in the mathematically consistent formalism, assuming one wishes to retain these classical terms at all.  Accepting this mathematical context produces a semantical change in the meanings of the terms with the result that they are no longer classical concepts and are therefore no longer antilogous.  The empirical adequacy of the quantum theory demonstrated after nonfalsifying test outcomes enable its equations to function as definitions.  This amounts to using the equations of the theory in a functionally a priori manner and as pattern statements, as Hanson had said, and to letting the theory decide what is observed, as Einstein had said.  Heisenberg may have been approaching the recognition of the semantical change, when in his "Questions of Principle" (1935) he said the restrictions on classical concepts as enunciated in the indeterminacy relations acquire their “creative value” only by making them questions of principle, such that they can have the freedom necessary for a noncontradictory ordering of experience.  Bohr’s complementarity is not noncontradictory.  The salient point is that in the light of Heisenberg’s autobiographical description of his development of the indeterminacy relations, his phrase “creative value” refers to the role of the mathematical equations in defining the semantics, so that the concepts of the formalism are used for observation as in the case of his reconsideration of the tracks in the Wilson cloud chamber.  In other words he recognized that the formation of a new semantics is integral to the new scientific discovery.  In this same paper Heisenberg also states that the system of mathematical axioms of quantum mechanics entitles the physicist to regard the question the simultaneous determination of position and impulse values as a false problem, just as Einstein's relativity theory makes the question of absolute time a false question in the sense that they are devoid of meaning.  Clearly the reason Heisenberg said such questions become devoid of meaning, is that the meanings of the variables have been changed, because demonstrated empirical adequacy of the quantum theory justifies giving semantical control to the descriptive vocabulary in new theory.

          Hanson reiterates Heisenberg's in-principle approach.  In the chapter "Elementary Particle Physics" in his Patterns of Discovery he states that one cannot maintain a quantum-theoretic position and still aspire to the day when the difficulties of the indeterminacy relations have been overcome, because this would be like playing chess and yet hoping for the day when the difficulties of having but one king chess-piece will have been overcome.  But Hanson is more consistent and he proceeds beyond Heisenberg.  Heisenberg's explicit and systematic theory of semantical change, his doctrine of closed-off theories developed under the influence of Bohr, was not only intended to explain semantical change, but was also intended to explain semantical permanence for classical concepts used for observation.  In contrast Hanson said that the indeterminacy principle is built into every observation of every fruitful experiment since 1925.  In Hanson's explicit and systematic philosophy of science, unlike Heisenberg's, the theory controls even the semantics of the language used for description of observed phenomena.  Hanson states how a theory has its creative value in ways that Heisenberg actually used and chronicled in his development of the indeterminacy principle, but which Heisenberg did not incorporate into his explicit and systematic philosophy, his doctrine of closed-off theories.  Heisenberg was inconsistent when he viewed the semantics of the variables in the mathematical quantum theory as classical concepts with restricted applicability for observation.

          One problematic and indeed controversial outcome of the semantical change resulting from giving semantical control to the formalism of the theory, as Hanson advocates, is a complication in the problem of how empirical control is also exercised over the theory in scientific criticism, such that independent evidence enabling empirical decidability is possible and tautology is avoided. This is a problem that still vexes those contemporary Pragmatists who employ a wholistic thesis of the semantics of language.  Hanson could have called upon his thesis of theory-independent phenomenalist seeing as an observation language.  But he never invokes this idea to defend the empiricism of science, even while he never doubts either the empirical decidability of science or the theory-laden character of observation language.  Instead he regrettably invokes Wittgenstein's idea of the multiple uses of language with theory language having a concept-defining function for observation only in some uses and a testing function in others.  This seems no better than Heisenberg’s inconsistency, and more obscurantist.

          (3) Thirdly consider Hanson's principal criticism of Bohm's hidden-variable interpretation of quantum theory.  Hanson's criticism is that Bohm has not developed any new empirically testable equations.  Initially Bohm had proposed his hidden-variable hypothesis as a heuristic for developing new microphysical equations that would resolve the renormalization problem, as well as unify physics with an ontology that is consistent for both macrophysics and microphysics.  For forty years he elaborated his interpretation of the existing quantum theory formalism, while the postulated subquantum field has remained remote from experimental detection, and while the renormalization problem remains unsolved.  In his "Hidden Variables and the Implicate Order" in Quantum Implications Bohm admits that his proposed hidden-variable interpretation did not “catch on” among physicists, since it gives exactly the same predictions for all experimental results as does the Copenhagen interpretation, which he calls the “usual” theory. 

          Hanson's critique of Bohm’s hidden-variable interpretation in his "Postscript" in Quanta and Reality seems to have been vindicated to date by the behavior of the physics profession in the years that have since elapsed. There is no shortage of sociological and conspiracy theories about the exclusion of Bohm and his supporters.  Some philosophers of science as well as supporters of Bohm claim that the advocates of the Copenhagen interpretation have imposed some kind of hegemony on the physics profession.  Bohm claims in his Undivided Universe, that the Copenhagen interpretation prevails only because it was prior to his interpretation, and says that it is merely a historical circumstance if not an accident that the Copenhagen interpretation was chronologically prior to his alternative interpretation. 

          But such claims reveal a failure to understand the institutional value system of empirical science that guides and motivates scientists’ opportunistic decisions – including the decision by the majority to ignore Bohm’s highly speculative hypotheses about phenomena occurring at a subquantum order of magnitude that is still experimentally undetectable.  Physicists prefer what Bell calls a pragmatic attitude.  They are not interested in alternative interpretations for their own sake, i.e. interpretations that are not associated with new and empirically testable equations that solve problems, which the current mathematical physics has yet to solve.  In fact the whole issue of alternative semantical and ontological interpretations for the quantum theory’s formalism is often ignored in textbooks on quantum theory.  And the Swedish Royal Academy does not award the Nobel Prize merely for novel interpretations.  Instead researchers in microphysics have allocated their time and effort to theorizing about the wealth of new data made available with the particle accelerators by developing the standard model and by developing string theory to account for gravitation as well.  Eventually new experimental techniques and apparati will enable physicists to detect and examine subquantum phenomena.  It would indeed be quite remarkable if in fact absolutely nothing actually exists at subquantum orders of magnitude, as Bohr had thought. 

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