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> Hasn’t quantum mechanics demolished the hope that science will make reality intelligible? > Not in the least. As Bell said, study Bohm’s pilot wave theory an

by dghf 8y ago

> Hasn’t quantum mechanics demolished the hope that science will make reality intelligible? > Not in the least. As Bell said, study Bohm’s pilot wave theory and you see that everything can be explained perfectly well, with no funny business at all logically or conceptually. We are stuck with non-locality, as Bell proved, but maybe in the end you need non-locality for the deep simplicity of law that I anticipate. I'm not a physicist, but isn't dumping locality a bit of a bigger deal than this quote suggests?

gus_massa 8y ago
Yes, it is! I think that Bohm’s pilot wave theory is appealing to non technical people because it replace all the scary equations of quantum mechanics with a wave and a particle. The trick is that the wave has a scary equation, and the interaction of the wave and the particle has a scary equation, but you can hide the scary equations behind a nice animated graph of a wave and a ball. For a nonrelativistic particle, the pilot wave is equivalent to the other quantum mechanics interpretations. The other interpretations can be extended to the special relativity case, moreover all the work in the last 50 (or more) years in particle physis use the extended versions. Nobody know how to extend the pilot wave theory, and perhaps it's impossible.
- crazygringo 8y ago
  I think you're being quite disrespectful in claiming that Bohm's theory is only appealing to "non technical" people, because it hides "scary" parts. The appeal of Bohm is that it results in QM that is deterministic, without needing to resort to ill-defined notions of collapse. I'm quite sure "hiding the scary equations" has absolutely zero to do with it, and it honestly comes across as offensive to suggest that it is.
  - Koshkin 8y ago
    > ill-defined notions of collapse Actually, the wavefunction collapse is a very well defined mathematical construct; so, if you are ignoring or trying to avoid it, you are literally "hiding the scary equations."
    - crazygringo 8y ago
      It's well-defined mathematically but ill-defined philosophically. There is no agreement on what an "observation" is -- that is what is ill-defined: > The Copenhagen interpretation is the oldest and probably still the most widely held interpretation of quantum mechanics. Most generally it posits something in the act of observation which results in the collapse of the wave function. According to the von Neumann–Wigner interpretation the causative agent in this collapse is consciousness. How this could happen is widely disputed. https://en.wikipedia.org/wiki/Measurement_problem https://en.wikipedia.org/wiki/Measurement_problem
      - gus_massa 8y ago
        It's an open problem, and I'm not sure if there are official tallies, but I think that currently most people think that the explanation is decoherence instead of consciousness. From the same Wikipedia page: > Erich Joos and Heinz-Dieter Zeh claim that the phenomenon of quantum decoherence, which was put on firm ground in the 1980s, resolves the problem. The idea is that the environment causes the classical appearance of macroscopic objects.
- naasking 8y ago
  I think you're unnecessarily dismissive of pilot waves and people who accept them. There are plenty of compelling properties of pilot wave theories, like a proper accounting of measurement. Even John Bell of Bell's theorem suggested that the greatest problem facing physics was integrating the non-locality of QM with relativity, and the fact that pilot waves place this non-locality front and centre is a feature not a bug, because other interpretations can more easily sweep this under the rug only for difficulties to show up later. Also, there are many perfectly fine relativistic extensions of pilot wave theories, so that claim is factually incorrect. They haven't settled on a canonical one, but pilot wave physicists get probably 0.01% of the funding of other physics work, so that's hardly surprising.
  - akkartik 8y ago
    A recent experiment actually seems to disprove pilot wave theories once and for all: https://www.quantamagazine.org/famous-experiment-dooms-pilot-wave-alternative-to-quantum-weirdness-20181011 https://www.quantamagazine.org/famous-experiment-dooms-pilot... (discussed a few weeks ago at https://news.ycombinator.com/item?id=18198811 https://news.ycombinator.com/item?id=18198811)
    - naasking 8y ago
      You can see my comment about it here: https://news.ycombinator.com/item?id=18201035 https://news.ycombinator.com/item?id=18201035

by dghf 8y ago

gus_massa 8y ago

Yes, it is! I think that Bohm’s pilot wave theory is appealing to non technical people because it replace all the scary equations of quantum mechanics with a wave and a particle. The trick is that the wave has a scary equation, and the interaction of the wave and the particle has a scary equation, but you can hide the scary equations behind a nice animated graph of a wave and a ball. For a nonrelativistic particle, the pilot wave is equivalent to the other quantum mechanics interpretations. The other interpretations can be extended to the special relativity case, moreover all the work in the last 50 (or more) years in particle physis use the extended versions. Nobody know how to extend the pilot wave theory, and perhaps it's impossible.

crazygringo 8y ago
I think you're being quite disrespectful in claiming that Bohm's theory is only appealing to "non technical" people, because it hides "scary" parts. The appeal of Bohm is that it results in QM that is deterministic, without needing to resort to ill-defined notions of collapse. I'm quite sure "hiding the scary equations" has absolutely zero to do with it, and it honestly comes across as offensive to suggest that it is.
- Koshkin 8y ago
  > ill-defined notions of collapse Actually, the wavefunction collapse is a very well defined mathematical construct; so, if you are ignoring or trying to avoid it, you are literally "hiding the scary equations."
  - crazygringo 8y ago
    It's well-defined mathematically but ill-defined philosophically. There is no agreement on what an "observation" is -- that is what is ill-defined: > The Copenhagen interpretation is the oldest and probably still the most widely held interpretation of quantum mechanics. Most generally it posits something in the act of observation which results in the collapse of the wave function. According to the von Neumann–Wigner interpretation the causative agent in this collapse is consciousness. How this could happen is widely disputed. https://en.wikipedia.org/wiki/Measurement_problem https://en.wikipedia.org/wiki/Measurement_problem
    - gus_massa 8y ago
      It's an open problem, and I'm not sure if there are official tallies, but I think that currently most people think that the explanation is decoherence instead of consciousness. From the same Wikipedia page: > Erich Joos and Heinz-Dieter Zeh claim that the phenomenon of quantum decoherence, which was put on firm ground in the 1980s, resolves the problem. The idea is that the environment causes the classical appearance of macroscopic objects.
naasking 8y ago
I think you're unnecessarily dismissive of pilot waves and people who accept them. There are plenty of compelling properties of pilot wave theories, like a proper accounting of measurement. Even John Bell of Bell's theorem suggested that the greatest problem facing physics was integrating the non-locality of QM with relativity, and the fact that pilot waves place this non-locality front and centre is a feature not a bug, because other interpretations can more easily sweep this under the rug only for difficulties to show up later. Also, there are many perfectly fine relativistic extensions of pilot wave theories, so that claim is factually incorrect. They haven't settled on a canonical one, but pilot wave physicists get probably 0.01% of the funding of other physics work, so that's hardly surprising.
- akkartik 8y ago
  A recent experiment actually seems to disprove pilot wave theories once and for all: https://www.quantamagazine.org/famous-experiment-dooms-pilot-wave-alternative-to-quantum-weirdness-20181011 https://www.quantamagazine.org/famous-experiment-dooms-pilot... (discussed a few weeks ago at https://news.ycombinator.com/item?id=18198811 https://news.ycombinator.com/item?id=18198811)
  - naasking 8y ago
    You can see my comment about it here: https://news.ycombinator.com/item?id=18201035 https://news.ycombinator.com/item?id=18201035