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December 18th, 2006

Physics and Philosophy

I just saw an interesting post on the Bohm interpretation of quantum mechanics, arguing that it doesn’t really help explain any of the interesting facts of quantum computing. (I think the many-worlds interpretation might help, but I’m no expert.)

However, I think the discussion was particularly interesting because it shows what physicists thinking about philosophical questions think “philosophical” means:

The unfortunate word “interpretation” suggests that foundational work should never impact the ring-fenced portion of the theory and should be confined to something like “finding the right language” for talking about quantum theory in order to avoid the difficulties with measurement, etc. Indeed, many philosophers actually like this distinction, because it makes “interpretation” a purely philosophical question that they can go off and study on their own, safe in the knowledge that they won’t find themselves proved wrong by physicists.

For my own part, I would have thought that this is a distinction that philosophers would want to reject. Isn’t it more appealing to the ambitious philosopher to say that the problem of interpretation is a philosophical question that is important to the physics. Thus, physicists will have to pay attention to us, even if it does mean that on some level we run the risk of being proved wrong by them.
Now, you may regard the “ontology problem” as a pure philosophy problem, to which physics can never supply a unique answer.

Calling a question philosophical is sometimes about the same for me as calling it moot. I agree that physics answers often have philosophical strength. In that sense, the philosophical aesthetic is valuable. But if you call a question philosophical, then you may be saying that if you don’t know if there really is a question.


Again, this seems to be a physicist with misconceptions about what philosophy is. (Though perhaps the fact that I think that just means that I have misconceptions about what philosophy is too.) I would have thought that once the Quine-Duhem problem was noted, it would be clear that “physics can never supply a unique answer” doesn’t mean that a question isn’t part of physics. In fact, the existence of this sort of question, which physicists do seem to find interesting once in a while (never mind their accusations at string theorists and others of engaging in pseudo-science) seems to me to lend strong support for a naturalist position on which there is no solid distinction between philosophical and physical questions, and the answers to either can have impacts on the other.

Anyway, it does seem strange to me that there’s so much discussion of the philosophical aspects of physics on the blogosphere, and so little input from actual philosophers of physics in these debates. It would seem that many of the physicists involved don’t even know that philosophers of physics exist! Is this the sort of case where our profession needs to assert itself a little more, or is it not even worth the attempt to win the hearts and minds of physicists?

Posted by Kenny Easwaran in Uncategorized

3 Comments »

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3 Responses to “Physics and Philosophy”

  1. joshparsons says:

    I’ve been running (well, co-running with a contact in physics) a reading group on philosophical aspects of QM. It’s mainly attended by experimental physicists who are curious about what philosophers say about physics.

    They are absolutely full of this sort of demarcation. (And also a little confused about its implications – for example, they tend to identify the “physics” part of QM both with the mathematical formalism, and with some kind of not very well spelled out minimal instrumentalist interpretation “all about what happens in the lab”). I think that, understandably, they want whatever background philosophy of science makes their job easiest.

    I’ve learned from bitter experience that the only way to make this group work is to be ruthless about sticking to the readings. Try to talk about the merits (or lack thereof) of global scientific instrumentalism or about confirmation holism and things just go off the rails, and it becomes like a bad first year tute.

    So I don’t challenge my physics friends over the demarcation issue. It’s actually easier to get them to behave by endorsing it, since then by coming to the group they are agreeing to talk about “matters of interpretation” (which they have useful and intelligent things to say about) rather than just saying “ah, but it’s not physics is it” over and over.

    But they probably will come away with the idea that philosophers think there is a rigid distinction between “philosophical” and “physical” questions. That’s the price you pay for getting them to take the “philosophical” questions seriously.

  2. P.D. Magnus says:

    You write: ‘I would have thought that once the Quine-Duhem problem was noted, it would be clear that “physics can never supply a unique answer” doesn’t mean that a question isn’t part of physics.’ This is right, I guess, but it elides an important distinction.

    There are two underdeterminations one can can find in Quine. The first (the DQ problem) is that physics can never supply a unique answer to any question. This is the underdetermination of theory by data; physicists would probably deny that it is a problem. Regardless, it does not seem to be the kind of non-uniqueness at issue here.

    The second sort is the indeterminacy of reference, which we might call the underdetermination of ontology by theory. Even if there were no DQ problem and physicists could identify a unique best theory, this can still arise. I think this is what people are trying to get at when they disntinguish quantum theory from the interpretation of the theory. Interpretation is a matter of identifying the proper ontology, which is a separate matter from selecting the best theory.

  3. Kenny Easwaran says:

    pmagnus – That’s a good point. I knew that it looked like a lot of pre-Quinean points that were being made by the physicists, but couldn’t quite call up what the relevant Quinean points were.

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