Readers offer their own magic moments with John Bell

Abstract

I greatly enjoyed reading Reinhold Bertlmann’s article “Magic moments with John Bell.” Sprinkled with levity, it discussed Bell’s life, work, and outstanding insights and achievements in the foundations of quantum mechanics (QM). In my view, the reading should also make one acutely aware that scientists, despite our expectations of them, are sometimes still prone to the same failings that beset the rest of humanity.Bertlmann outlines very nicely Bell’s theorem and inequalities and the consequences of their violation; that work led to the subsequent startling experimental results on “entangled” quantum mechanical states, which, Bertlmann writes, showed “that nature contains a nonlocality in its structure.” Nonlocality, in Bell’s conception of it, is clearly a violation of special relativity (SR), so we have a problem. The startling thing for me is that Bell actually does appear to solve the problem, at least in principle, but at the same time he seems afraid to say so and, in fact, distances himself from the proposed solution.The essence of his ambivalence is conveyed in the following paragraph, quoted by Bertlmann:It may be that we have to admit that causal influences do go faster than light. The role of Lorentz invariance in the completed theory would then be very problematic. An “ether” would be the cheapest solution. But the unobservability of this ether would be disturbing. So would be the impossibility of “messages” faster than light.Clearly, faster-than-light propagation is not possible in SR. But it is permissible in the approximately 100-year-old ether-based Lorentzian theory of relativity (LR), developed by Joseph Larmor, Hendrik Lorentz, Henri Poincaré, and others. Bell was explicitly cognizant of LR and discussed it in his book Speakable and Unspeakable in Quantum Mechanics (2nd edition, Cambridge University Press, 2004). It is well known that LR and SR are totally congruent in their kinematics and dynamics, for speeds equal to or less than c. All predictions are identical. However—though one cannot find this in any standard textbooks—the LR ether theory differs from SR by allowing, without contradiction, speeds greater than c.Historically, Einstein’s SR gained ascendancy, and LR was relegated to the scrap heap of history for many reasons, but I think predominantly for the following. SR was viewed as being far more elegant and simple to develop—from the perspective of theory formation—because it followed deductively from Einstein’s two simple axioms. On the other hand, LR theory was developed from a realism perspective, where waves were thought to need a medium to wave in (the luminiferous ether).Considering that Bell was clearly aware of LR and was entertaining the idea, albeit reluctantly, of “causal influences [going] faster than light”—that is, being consonant with LR—I find it difficult to understand his expressions in the quote above about cheap solutions and disturbing features. It seems to be part of human psychology that once a set of ideas or a theory is accepted as valid for a long enough time by a community of people, as has been the case for SR, it gets transformed into belief, psychologically not unlike religious belief. Once that happens, those who would question the established dogma are treated as if the questioning was ill-intentioned, if not downright sacrilegious.© 2015 American Institute of Physics.