Response to Norsen: The Enigma Remains!
Ordinarily, this journal is not a proper venue for a discussion of the fundamentals of quantum mechanics. But the issue here is how the teaching of quantum mechanics can counter the use of quantum mechanics to provide support for pseudoscience. In the April edition of this journal we argued[i] that by not properly dealing with the human implications of quantum mechanics, we leave that field to the purveyors of pseudoscience. We cited the movie “What the Bleep?” as an example. We noted that while a biology student is able to effectively refute Intelligent Design’s challenge to evolution, a physics student, with a typically limited understanding of the quantum enigma, is not similarly prepared to refute quantum nonsense. We can provide that preparation by briefly confronting those human implications when we teach quantum mechanics.
Travis Norsen[ii] takes issue with this. He maintains that if the Copenhagen interpretation of quantum mechanics, which he calls “just as unscientific as Intelligent Design,” is replaced by the Bohm interpretation, the problem we are concerned with disappears. The Bohm interpretation, according to Norsen: “…avoids completely the unscientific baggage and subjectivist implications of the Copenhagen approach… In short, it has none of the subjectivist-epistemological ‘human implications’ which Kuttner and Rosenblum urged on us, in the previous issue of this journal, to explore with our students.”
We believe the usual presentation of quantum mechanics based on the Copenhagen interpretation is just fine for all practical purposes, as long as Copenhagen is recognized as one of several current interpretations of quantum mechanics. While each interpretation of quantum mechanics recognizes human implications, each shows how the physics discipline need not deal with them. Students should, however, understand that if we explore beyond practical purposes, quantum mechanics presents us with an unresolved mystery. Understanding the nature of that mystery, students will know the limits to what can legitimately be implied from it.
But according to Norsen, there is no mystery to explore. The Bohm interpretation tells us that that instead of particle or wave (yielding the wave/particle paradox) we have particle and wave. “And that’s that. The paradox is resolved: there are two entities, a wave and a particle,” says Norsen. Not quite so fast. The Bohm interpretation also requires a third entity, a “quantum potential” yielding a quantum force guiding particles to obey the Schrödinger equation. The quantum potential is otherwise completely undetectable. This potential provides the required instantaneous connection of a particle with all other particles with which it has ever interacted, in principle, with everything--including the conscious observer. (Is this well-established interaction mysterious? Einstein called it “spooky.”)
The Bohm interpretation thus does not avoid the subjectivist implications of quantum mechanics. In fact, the mysterious implications of quantum mechanics can never be resolved by any mere interpretation of the quantum theory. The enigma arises directly from the (quantum) theory-neutral experiment, which is logically prior to the quantum theory. [iii]
The Bohm interpretation is sometimes discussed as eliminating the involvement of the observer.[iv] It is usually not clear in such discussion whether this elimination of the observer is supposedly true in principle or merely for all practical purposes. In the former case, the complete determinism of the Bohm interpretation would deny the observer’s free will. David Bohm himself considered the elimination of the observer to be only for all practical purposes. He has written: “…the intuition that consciousness and quantum theory are in some sense related seems to be a good one…”[v]
John Bell is sometimes quoted, and is by Norsen, as implying the Bohm interpretation resolves the wave-particle paradox. Actually, Bell’s opinion (which we share!) is that Bohm is one of the “roads open … towards a precise theory…,” but that theory has not yet been achieved. In one of the last papers he wrote Bell speculates that we might find “… an unmovable finger obstinately pointing outside the subject, to the mind of the observer…”[vi]
Discussion of the human implications of quantum mechanics increases today as interpretations proliferate. It is unfortunate that the subject also is increasingly fodder for the promoters of pseudoscience. In such presentations even many physics students can have trouble telling where the real quantum weirdness ends and the quantum nonsense begins. It is our responsibility in teaching physics to deal openly with the mystery physics has encountered, which has been called our “skeleton in the closet.” This can be done in a single lecture or two, even in a “physics for poets” course. In fact, that level might be where we would get the most bang for the buck. We have been able to present it at that level in courses and in a book.[vii]
[i] F. Kuttner and B. Rosenblum, “,” Forum on Physics and Society of the American Physical Society, Vol. 35 No. 2, April 2006
[iii] B. Rosenblum and F. Kuttner, “The Observer in the Quantum Experiment,” Foundations of Physics, Vol. 32 No. 8, August 2002
[iv] S. Goldstein, “Quantum Mechanics Without Observers-Part Two,” Physics Today 51(4), 38-42 (1998)
[v] D. Bohm and B. J. Hiley, The Undivided Universe, Routledge, London, 1993, p. 381
[vi] J. Bell, “Against ‘Measurement,’” Physics World, August 1990, pp. 33 - 40
[vii] B. Rosenblum and F. Kuttner, Quantum Enigma: Physics Encounters Consciousness, forthcoming from Oxford University Press, August 2006
Fred Kuttner and Bruce Rosenblum
Department of Physics
University of California, Santa Cruz
Santa Cruz, CA 95064
phone 831-459-2326 fax 831-459-3043