Friday, March 21, 2008

Interpretation of Quantum Mechanics - The New Religion

First of all, a clarification and a qualification. Most physicists (at least the ones that I come in contact with throughout my years as a student and as a physicist) don't really care about the various interpretations of quantum mechanics. It really is a non-issues 99.9% of the time. So essentially, we practice Feynman's "Shut Up And Calculate" philosophy where the formalism and what empirical evidence that it can produce is what we care about.

Now, in one of my rants in "Imagination Without Knowledge is Ignorance Waiting to Happen", I mention about many crackpots who have argued that physicists simply want to keep the status quo as far as our understanding of the universe goes, that all we care about is upholding the current laws and theories. We can't, as some put it, work "outside the box". Some even compare to our "devotion" towards not wanting to drop our current understanding as a "religion".

This, of course, is stupid, and false, on many different levels, as I've mentioned in that blog entry. Still, there is one aspect of physics in which, I hate to say, is starting to look like a religion, and it has nothing to do whatsoever with what these crackpots have in mind. In fact, I don't think any of them could even comprehend these things well enough to know any better.

What I find in physics to be no different than a religion is the rabid devotion of some people, physicists included, to the various interpretation of quantum mechanics. These interpretations could range from the "popular" Copenhagen Interpretation (CI), to Many-World Interpretation (MWI), to Bohm Pilot Wave (BPW), etc.. etc. Now, again, to be fair, this issue comes up only in a very small percentage of practicing physicists. I tend to find more of these discussions on physics forums rather than in prominent physics journals. And certainly, amateurs and philosophers tend to be more fascinated by this issue than the overwhelming majority of physicists. So in physics, this "religion problem" isn't a widespread epidemic.

Still, those who are devoted to this is not doing physics any favor. I find that the rabid devotion to such various interpretation (rather than just a casual attitude about it) rather puzzling and contrary to how one accepts something to be valid in physics. This is why I find that the devotion to any such interpretation as being no different than a religion:

1. There's no empirical evidence that shows one being "better" than the other. All of them come up with the same analytical form within the formal QM. The similarities with religion is obvious here. This means that there's nothing to support which is better, and they all come up with the same answer, at best, so far.

2. Yet, the devotees in each camp tout why such-and-such is more "logical" or "rational" or "conceptually sensible", etc. Without empirical evidence to support such claim, this is nothing more than a preference based on a matter of tastes! We might as well argue for our favorite color, or, in this case, our favorite religion. This is no different than the different religions and the many followers that they have. Each one will tout the superiority of its belief system, or why it is the "truth", etc. Yet, in none of these are there any empirical evidence to separate and support these claims.

Now one could argue that isn't what is being taught in QM classes more along the lines of adopting the CI? I don't believe so, because in the end, it is the formalism that is more important, and there's no ambiguity at all there. And if it really is CI that is being instilled into these students, how come most of them grow up and adopt the "Shut Up and Calculate" point of view and not become a CI devotee?

I'm not saying that at some point, there won't be a "tie-breaker", be it a further refinement to these various interpretations that make them distinctly different from each other, and/or new tests would come out to allow for direct verification of each one. But until then, why are people "believing" in something that, at the very foundation, is simply a matter of tastes?


1 comment:

Peter said...

Interpretation is a significant part of how a Physicist decides what calculations to do. Students are told to "Shut up and calculate" because the profession has by now developed prosaic ways to decide what calculations to do. There is less guesswork needed these days at the engineering level so that many students do not have to engage with the Physics.

In research, however, guesswork is as much required as it ever was to decide what calculations might turn out interesting results. What interpretations we are willing to give head-time to is part of what determines what calculations we do, which may determine our success in research. Totally random investigation is not good, but some freedom of thought is necessary.

Encourage students to decide whether they want to be engineers in industry, in which case they should mostly learn the rules, without too many distractions; if they want to be research Physicists or Engineers, they will be better at it, eventually, if they decide for themselves where they will just use the rules and where they will make their own. An important aspect of a researcher's vantage point is their choice of interpretation of QM, or their willingness to think in the intuitive frameworks of several interpretations.