REALITY & QUANTUM MYSTICISM PART II A Realistic Interpretation of Quantum Mechanics by William B. Lindley As noted last issue in Part 1, quantum phenomena have been interpreted in such a way as to cast doubt on objective reality. I asked whether an interpretation fully compatible with objective reality was available. It is. A 1986 article by John G. Cramer, then of the Physics Department of the University of Washington in Seattle, details such an interpretation as well as reviewing the philosophical battles. His monograph appears in Reviews of Modern Physics, Vol. 58, No. 3, July 1986, and takes up 41 pages. Part 1 noted that a local realistic theory cannot fit the facts, as Einstein thought it must. "Local" means that there is no physical connection (causation, communication or correlation) faster than light or backward in time. A theory or interpretation must be either nonlocal or tied to an observer- dependent 'reality." Cramer's interpretation is "explicitly nonlocal and thereby consistent with recent tests of the Bell inequality, yet is relativistically invariant and fully causal." The idea of objective reality is that it is independent of the knowledge of observers. Cramer chooses to defend the significantly weaker assumption of "contra factual definiteness," the position that, for different possible measurements, each would produce a definite result, and this set of results is worth talking about. (It is worthwhile to speak of the unobserved noise the tree makes when it crashes.) contra factual definiteness is, of course, fully consistent with the philosophical stance of objective reality. Cramer's article is titled "The transactional interpretation of quantum mechanics." Its heart treats a quantum event as a transaction. We have an emitter and an absorber. The emitter sends an "offer wave" forward in time; it is received by the absorber, which sends a "confirmation wave" backward in time. Having said this, Cramer warns: "The account of an emitter-absorber transaction presented here employs the semantic device of describing a process extending across a lightlike or timelike interval of space-time as if it occurred in a time sequence external to the process. The reader is reminded that this is only a pedagogical convention for the purposes of description. The process is atemporal...." To some, this may sound even stranger and harder to believe than abandoning reality, but the "transcendental temptation," as Paul Kurtz put it, may be at work here. The facts are strange, and any theory that fits them will have strange features. The idea of waves moving both forward and backward in time is not new to Cramer. It was first put forth in a paper by Feynman and Wheeler in 1945. They were trying to solve the problem of the self-energy of the electron, and this paper didn't do the job, but the idea was there, and Cramer adopted it for his transactional interpretation. The Copenhagen interpretation's indifference to reality is not the only, or even perhaps the primary, objection that Cramer has to it. He offers two lists of criteria that he believes the interpretation of a physical theory should satisfy: a general list and one for quantum mechanics in particular. The first list: (1) Economy (Occam's razor); (2) Compatibility: an interpretation should agree with physical laws, even those not immediately pertinent to the theory — the failures here are called "interpretational paradoxes," and Cramer indicates that the Copenhagen interpretation has several of these; (3) Plausibility; (4) Insightfulness (Cramer uses Faraday's concept of field lines as an example). The second list: "(1) [The interpretation] should permit the operation of the microcosm to be isolated from the macrocosm and particularly from intrinsically complicated macroscopic concepts, e.g., knowledge, intelligent observers, consciousness, irreversibility, and measurement; (2) it should account for the nonlocal correlations of the Bell inequality tests in a way consistent with relativity and causality; (3) it should account for the collapse of the state vector without subjective 'collapse triggers' (e.g., consciousness); and (4) it should give added meaning to the state vector and provide insights into the problems of complexity*, completeness, and predictivity." In some detail, he finds where the Copenhagen interpretation falls short of satisfying these criteria, while his transactional interpretation satisfies them. (*Complexity here means involving the square root of minus one.) Time is a difficult concept when you get away from ordinary experience. We tend to extrapolate too much. For example, the basic physical laws are invariant under timereversal, that is, they work whether you go forward or backward in time. The Schrodinger equation, which most people bear in mind when discussing interpretational questions, is not; Cramer reminds us that this "equation is ultimately not physically correct because it is not relativistically invariant." The correct wave equation for quantum mechanics is the Dirac equation. In some of the current work on the first moments of the universe, people are using equations where time doesn't even appear as a parameter. In human psychology, backward-in-time interpretation of events (of the order of tenths of a second) occurs. In facing reality, we must recognize that some of our intuitions about time are not universally valid. The transactional interpretation has not received the attention it deserves. However, it may at last be getting it. The issues of interpretation have been a hot item in the journal Foundations of Physics in recent years. Let me quote the MIT physicist Victor F. Weisskopf (1980): "The ideas of quantum mechanics do not contain any reasons whatsoever for giving up the concept of a reality that is independent of the mind.... Quantum mechanics presents us with a much richer reality than we are accustomed to encountering in macroscopic physics. That is why it succeeded in describing what we actually observe in the atomic realm." And a few words from John Bell, the very man whose theorem contradicted Einstein's claims. Interviewed by Omni magazine, he is asked: "This movement to link physics and mysticism — do you think it's bad?" Bell: "I don't think it's evil, but I don't think it's right. In my opinion physics has not progressed far enough to link up with psychology or theology or sociology.... I don't think Bell's theorem moves you nearer to God." Omni: "Are people simply picking up the poetic resonances of these ideas?" Bell: Yes! Now, poetry — that's the correct way to see it.... So as poetry, I can appreciate Capra [author of The Tao of Physics] and others. But as physics, I don't appreciate them at all.... We'll all go and sit at the feet of Maharishi if he tells us where the Higgs boson is to be found."