Quantum Theory

aequinoctium

What's the philosophical interpretation of quantum theory?

Son Goku

If you mean "what does Philosophy make of Quantum Theory", then I'd have no idea.

If you mean what is the interpretation of what the mathematics says, then there are several of them (around 50). Although all the interpretations can be grouped into six families of very similar interpretations.

Amoung the most popular are the environmental decoherence interpretation, the relative state view(or many-worlds to use its popular name), the Copenhegan interpretation and the "Shut-up and calculate" interpretation.
These are the most popular because amoung them they account for 99.9% of physicists.

I'd be happy to give a description of any of the interpretations, however for the sake of honesty I'm on the fence between Copenhegan and "shut up and calculate".

EDIT: Correct mistake in last line, environmental decoherence changed to "shut up and calculate".

nesf

"Shut up and calculate the damn thing, if you try and think about it you'll just get yourself confused. Just solve the maths and walk away from it and never look back".

-Anon




The problem is whether you assume that the maths has to mean something or not. That's the initial question to ask imho.

Son Goku

nesf wrote:

The problem is whether you assume that the maths has to mean something or not. That's the initial question to ask imho.

Personally, I think the maths does mean something. Mainly because it was derived from physical principles that human beings can grasp and also because the derivations took physical ideas into account. It was never purposefully created as an accurate model, but as an actual description of physical systems.

In this sense, I don't think it is that different to GR and Newtonian Mechanics, in that it follows the pattern of:
Assuming these principles are correct, this framework follows. The difference is that unlike GR and NM, the QM framework isn't easy to comprehend. (Of course replace "isn't easy" with "nearly impossible".)

Besides even ignoring the maths you have experimental results like the Aharonov-Bohm effect, that make no sense.

I guess what I'm saying is that I don't think the Popperian attitude of "It's a mathematical framework, which only seeks to model reality, so it doesn't mean anything" is going to be enough to fully deal with QM. Somebody will have to seriously think about what it means.

Again, that's what I think.

Playboy

Son Goku wrote:

. Somebody will have to seriously think about what it means.

Probably at the risk of losing their minds

nesf

Son Goku wrote:

I guess what I'm saying is that I don't think the Popperian attitude of "It's a mathematical framework, which only seeks to model reality, so it doesn't mean anything" is going to be enough to fully deal with QM. Somebody will have to seriously think about what it means.

I'd come at it from the Popperian angle personally. I don't view the rest of physics as being much different except in that the maths is more 'intuitive'. For me electro-mag just makes 'sense'. I look at an equation and I can see the 'shape of the field' in my head if you know what I mean, but this doesn't mean that the equations are anything more than a mathematical framework that might help me arrange concepts into something that is useful for me.

Son Goku

nesf wrote:

I'd come at it from the Popperian angle personally. I don't view the rest of physics as being much different except in that the maths is more 'intuitive'. For me electro-mag just makes 'sense'. I look at an equation and I can see the 'shape of the field' in my head if you know what I mean, but this doesn't mean that the equations are anything more than a mathematical framework that might help me arrange concepts into something that is useful for me.

I like where this is going.:) Hopefully I can get some feedback on the philosophical issues I may be ignoring.

I suppose this might be crude philosophically, but I tend to think that because the theory has been successful in describing reality there is some element of "truth" to it. However to qualify what I mean I'll take a simple example.

Take this object (stupid I know):

Newtonian Dynamics and elementary vector calculus can describe the dynamics of this box and do so in an intuitive manner. I pick this example because in this case the equations are nothing more than a mathematical framework that might help me arrange concepts into something that is useful for me.(As you said)
In reality the box is a countable collection of discrete atoms, not the uncountable continuum of points Newtonian Dynamics and vector calculus assume. (Which means it isn't even really a cuboid)
However I still think Newtonian Dynamics and vector calculus are true, in a way. Perhaps I should call it "emergent truth" or truth "at that level", in the sense that nothing terribly incorrect will come from considering it with Newtonian Dynamics and vector calculus. In other words, at that scale, they might as well be true and will lead you to correct conclusions about objects in that regime.

How does this lead into QM?

I will again rob an example of yours, Maxwell's equations for Electro-Mag.
The two important entities in these equations are E and B.
(The Electric field and Magnetic flux respectively, if anybody doesn’t know)
Thinking in terms of Maxwell's Equations you would be lead to believe E and B are the real entities. However the Aharonov-Bohm effect shows that not to be the case. It's really A and φ, the potentials, that are real (or at least realer), even though Maxwell's Equations don't describe them explicitly.

Never the less, the fact that Maxwell's equations for E and B are invariant under a certain transformation is what lead Einstein to Special Relativity. Despite the fact that E and B aren't real. I think this was because there was enough physical content captured in E and B at the classical level they described, despite their unreality, to point to special relativity.

So looking at the meaning of QM might be a similar prospect in my mind. QM has been successful enough to warrant the notion that there is something important captured by the ideas of matter particle-waves and probabilistic wavefunctions, that will probably lead us somewhere if we crack what it means at that level.

Is this sensible?

nesf

Son Goku wrote:

I think this was because there was enough physical content captured in E and B at the classical level they described, despite their unreality, to point to special relativity.

That is pretty much where a lot of my thinking on this stuff leads. The best way I can describe it is that physics is a bit like a black and white photograph. You can't see red in the picture but a lot of the time you can spot a few things in the photo that 'are' red but that doesn't mean that the world actually looks like a black and white photograph. Similarily we can infer things about reality from our models but that doesn't require or mean that our models are in any sense real, only that in some way they are coherent with reality with respect to the inferences we wish to make (think in terms of using GR to descibe the way quarks behave; the inferences we want to make are what results in the model becoming incoherent wrt reality rather than the model being incoherent in general wrt reality).

I keep falling back to the idea of conjectures approaching reality rather than actual descriptions of reality. This, of course, is probably because I find the idea of 'limits' intuitive after all the years spent in the subject.

Carrigart Exile

aequinoctium wrote:

What's the philosophical interpretation of quantum theory?

Without wishing to insult anyone and this is a genuine response I think its the Forest Gump answer 'S*** happens'

Fremen

"The best way I can describe it is that physics is a bit like a black and white photograph. You can't see red in the picture but a lot of the time you can spot a few things in the photo that 'are' red but that doesn't mean that the world actually looks like a black and white photograph."

What an excellent description. I've never been able to verbalise my understanding of the connection between physics and reality (sic).
That came pretty damn close, cheers.