Underdetermination of Theory by Metaphor

Sometimes I explain science in unconventional ways. I’ll talk about quantum mechanics without ever using the word “measurement”, or write the action of the Standard Model in legos.

Whenever I do this, someone asks me why. Why use a weird, unfamiliar explanation? Why not just stick to the tried and true, metaphors that have been tested and honed in generations of popular science books?

It’s not that I have a problem with the popular explanations, most of the time. It’s that, even when the popular explanation does a fine job, there can be good reason to invent a new metaphor. To demonstrate my point, here’s a new metaphor to explain why:

In science, we sometimes talk about underdetermination of a theory by the data. We want to find a theory whose math matches the experimental results, but sometimes the experiments just don’t tell us enough. If multiple theories match the data, we say that the theory is underdetermined, and we go looking for more data to resolve the problem.

What if you’re not a scientist, though? Often, that means you hear about theories secondhand, from some science popularizer. You’re not hearing the full math of the theory, you’re not seeing the data. You’re hearing metaphors and putting together your own picture of the theory. Metaphors are your data, in some sense. And just as scientists can find their theories underdetermined by the experimental data, you can find them underdetermined by the metaphors.

This can happen if a metaphor is consistent with two very different interpretations. If you hear that time runs faster in lower gravity, maybe you picture space and time as curved…or maybe you think low gravity makes you skip ahead, so you end up in the “wrong timeline”. Even if the popularizer you heard it from was perfectly careful, you base your understanding of the theory on the metaphor, and you can end up with the wrong understanding.

In science, the only way out of underdetermination of a theory is new, independent data. In science popularization, it’s new, independent metaphors. New metaphors shake you out of your comfort zone. If you misunderstood the old metaphor, now you’ll try to fit that misunderstanding with the new metaphor too. Often, that won’t work: different metaphors lead to different misunderstandings. With enough different metaphors, your picture of the theory won’t be underdetermined anymore: there will be only one picture, one understanding, that’s consistent with every metaphor.

That’s why I experiment with metaphors, why I try new, weird explanations. I want to wake you up, to make sure you aren’t sticking to the wrong understanding. I want to give you more data to determine your theory.

8 thoughts on “Underdetermination of Theory by Metaphor

  1. Lubos Motl

    You must have missed it but it has become absolutely normal to talk about quantum mechanics without ever mentioning the measurement. The measurement has literally become politically incorrect. This status of the paramount concept of quantum mechanics is the main reason why virtually no one understands basic quantum mechanics today at all.

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  2. duffieldjohn

    Time doesn’t run faster in lower gravity. Optical clocks go slower when gravitational potential is lower, because light goes slower at that lower elevation. Curved spacetime isn’t curved space and curved time, it’s space that’s “neither homogeneous nor isotropic compelling us to describe its state by ten functions (the gravitation potentials gμν)”, and where the inhomogeneity is non-linear. Unfortunately a lot of people haven’t read the original material in the Einstein digital papers. They base their understanding of the theory on the wrong metaphor by the 1960s popularizer who appealed to Einstein’s authority whilst flatly contradicting the guy. Hence they end up with the wrong understanding.

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      1. duffieldjohn

        It wasn’t off topic, and it was physics, not spam. There’s no electron model in QED so renormalization is a kludge, and the Standard Model can’t tell you how a magnet works. See this discovery magazine article re the latter: http://discovermagazine.com/2008/may/02-three-words-that-could-overthrow-physics.

        PS: I posted the above as a reply, but it disappeared immediately. Have I been blackballed for pointing these physics issues? Or for addressing them?

        Regards
        John Duffield

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        1. 4gravitonsandagradstudent Post author

          You haven’t been blackballed, but after a post is marked as spam wordpress will be more cautious about posts from the same author in future. In particular, short comments with links often trigger its spam filter.

          Regardless, no-one in the post or comments had mentioned renormalization, QED, electrons, or magnets, so your comment was indeed off-topic.

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          1. 4gravitonsandagradstudent Post author

            Deleted your additional reply, as again, electromagnetism is off-topic with respect to this post. It would have been at least marginally on topic in the other post you mentioned, so if you feel the need to post it I would suggest posting it there.

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            1. duffieldjohn

              Matthew:

              I posted it in https://4gravitons.wordpress.com/2014/10/31/why-i-cant-explain-ghosts-or-a-review-of-a-popular-physics-piece/. It vanished. It’s probably in the spam folder.

              That’s the article where you talked about Juan Maldacena trying to explain gauge symmetry. Maldacena talked about electromagnetism, at length. But it’s clear that he doesn’t understand it. He spoke of electric fields and magnetic fields, he doesn’t know that electromagnetic field interactions result in linear “electric” force and/or rotational “magnetic” force. When the rotational forces balance we only see linear force and we say an electric field is present. When the linear forces balance we only see rotational forces and we say a magnetic field is present. Gauge invariance tries to get to the bottom of this, but it doesn’t explain the underlying physics.

              Regards
              John Duffield

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              1. 4gravitonsandagradstudent Post author

                Hadn’t noticed the comment in the spam filter. I’ve let it through, since as mentioned it’s (at least) on-topic. In future, if you’re worried about a comment being accidentally caught in the spam filter, use the blog contact form to let me know.

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