Magnetism - distilling the everyday from the extraordinary

Use this forum to discuss the philosophy of science. Philosophy of science deals with the assumptions, foundations, and implications of science.
Steve3007
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Re: Magnetism - distilling the everyday from the extraordina

Post by Steve3007 » June 3rd, 2014, 4:52 pm

Poster:
Relevant to your magnetism example? No. I was just providing another example of your point about how an everyday phenomenon experienced in a rather direct manner (namely, a mirage) requires underlying mechanisms not intuitively understood or even recognized at all.
Ah! OK.
Classical optics is pretty common-sensical and is often the sole model provided to explain a mirage. Quantum mechanics and sum-over-histories are well beyond common sense, in this case by specifically allowing (and even requiring) superposition to explain the mirage.
Yes, common-sensical as long as we accept certain things about rays of light which, on closer examination, perhaps turn out not to be so common-sensical after all. I guess we're all familiar and comfortable with the ray diagrams of classical optics. And we're all so used to the idea that it's possible to think of rays of light as little lines that we can, sort of, "see" bouncing between mirrors and refracting through lenses, that, when we first learn about these things at school, we rarely question precisely what it means to draw a diagram of a bunch of objects (which we would generally see by reflected light) which also includes a load of light (which we clearly don't see in that way).

It's true: I think we do see classical optics as pretty common-sensical. But it's perhaps interesting to ponder why we do.
I find that it is coherent specifically because you quickly abandon any requirement for magnetism as a classical force, commit your explanation entirely to the metaphors of Special Relativity, then simply note that such a tiny drag created by the Lorenz transformation is felt strongly because of the strength of the electromagnetic force. A good enough layman's understanding maybe, but it carries the internal discontinuity of failing to explain why such a time-drag would manifest as magnetic energy; the discontinuity smoothed over by a quick switch back to a classical model at the end.
Interesting perception of the OP.

I didn't think I was characterizing it as a "drag", as such. I was actually trying (possibly wrongly! It's been a long time since I studied any of this stuff) to express it using classical force concepts all the way through - the charge density increasing due to the length contraction, which results in an extra force - which can be understood simply as an extra electric force. The cause of the length contraction needs Special Relativity, but the idea was that its effect can be understood, in this kind of example, as a classical force.

The details of precisely how the magnetic force arises as a result of the Lorentz transformations is generally much more complex than presented here, but I was hoping that this specific example allows the whole thing to be understood in classical terms. The key take-home point, I think, is that the magnetic force is exactly the same thing as the electric force, but just viewed from a different reference frame. i.e. The Lorentz transformations apply to Maxwell's Equations in the way that Galilean transformations apply to Newton's equations.

I guess the thing that should perhaps have been emphasized more is this close identity between electricity and magnetism - that it's the same thing seen from different viewpoints. i.e. it's not so much that the Lorentz transformation manifests mysteriously as a magnetic force, but simply that this is what a magnetic force is. It is the definition of magnetism.
Yes, as I recall Feynman was demonstrating how his QM interpretation would be consistent with classical reality. Since Feynman was not a Copenhagenist, I assume he would consider it important to eliminate any suggestion of a sharp divide between the quantum and classical worlds.
Yes, and I think it's more than just eliminating the suggestion of a sharp divide at which the applicable laws have to suddenly change, but eliminating self-contradiction, since the classical and the quantum worlds are the same world.
"When the seagulls follow the trawler, it is because they think sardines will be thrown into the sea." - Eric Cantona.

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Re: Magnetism - distilling the everyday from the extraordina

Post by Obvious Leo » June 3rd, 2014, 5:21 pm

Steve3007 wrote:Yes, and I think it's more than just eliminating the suggestion of a sharp divide at which the applicable laws have to suddenly change, but eliminating self-contradiction, since the classical and the quantum worlds are the same world.
It's always refreshing to find a point of common ground. I don't think anybody seriously continues to believe that the sub-atomic world conforms to different laws of physics than the macro world of our experience. QM is a mathematical representation of the physical world, not an ontological description of it. The same could be said of SR, GR and the Standard Model.

Regards Leo

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Re: Magnetism - distilling the everyday from the extraordina

Post by A Poster He or I » June 4th, 2014, 5:10 pm

Steve,

Sorry to introduce the term "time-drag;" I should have stuck more closely to your own verbiage regarding the bunching up of electrons creating "extra" electrostatic force. And technically speaking, the Lorentz transformations ARE a classical theory since they don't involve Planck's constant, so you really didn't mix metaphors as I suggested (even if Maxwell knew nothing about the Lorentz transformations!).

I guess my only real issue is that since the classical paradigm cannot define what a "force" actually is (except as mathematical relations), I consider it mixing models to talk about electrons without discussion of photons as the carrier particle for the EM field (which would keep the explanation quantum mechanical instead of falling back on the classical force concept).

Obvious Leo,

You keep making a point of QM being merely a mathematical representation rather than an ontological description, but I don't really see the significance of this since all theories are merely epistemological representations. History shows us that any hubris we have toward believing that theories reveal ontological truths is eventually shot down when new theories subsume old ones.

Are you contrasting modern physics to classical physics, presuming that classical theories really do tell us about ontology???

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Re: Magnetism - distilling the everyday from the extraordina

Post by Obvious Leo » June 4th, 2014, 5:50 pm

A Poster He or I wrote: You keep making a point of QM being merely a mathematical representation rather than an ontological description, but I don't really see the significance of this since all theories are merely epistemological representations. History shows us that any hubris we have toward believing that theories reveal ontological truths is eventually shot down when new theories subsume old ones.
You'll get no argument from me. I keep referring to this point because many people seem to think that notions such as particle superposition and wave/particle duality somehow represent reality when in fact they they do no such thing. The less said about multiple universes and hidden dimensions the better but they fall into the same category.
A Poster He or I wrote:Are you contrasting modern physics to classical physics, presuming that classical theories really do tell us about ontology???
No I don't suggest that either. No theory of mechanics can be accommodated within the paradigm of spacetime, which is an action-at-a-distance model. This foundational assumption is false.

Regards Leo

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Re: Magnetism - distilling the everyday from the extraordina

Post by A Poster He or I » June 4th, 2014, 6:44 pm

Well, the ontologizing of science is a truly unfortunate byproduct of science's general success. I think science education is mostly to blame there, though in general, scientists themselves are no help there either.

Anyway, I'm still scratching my head a bit regarding your statement that "No theory of mechanics can be accommodated within the paradigm of spacetime, which is an action-at-a-distance model. This foundational assumption is false." It seems pretty obvious that mechanics is not only accommodated by spacetime, it requires spatio-temporal extension/duration to even be sensible. I feel what you mean to say is that mechanics does not define spacetime (that is, it tells us nothing about the ontological status of spacetime, and epistemologically it merely catalogs spacetime's behavior without telling us how it qualifies as an epistemic object).

The upshot of what I'm suggesting is that you seem to be targeting theory as the bogeyman for somehow committing some shortfall, when it seems to me that the discovery of non-locality vindicates QM's power as predictive theory (wave mechanics did predict nonlocality, after all). Analagously, the discovery of QM and Relativity a century ago taught us something new about classical mechanics: that it is not infinitely scalable, making us smarter in our usage of classical mechanics.

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Re: Magnetism - distilling the everyday from the extraordina

Post by Obvious Leo » June 4th, 2014, 7:36 pm

A Poster He or I wrote:Well, the ontologizing of science is a truly unfortunate byproduct of science's general success. I think science education is mostly to blame there, though in general, scientists themselves are no help there either.
This is exactly the problem I'm referring to and our positions are more in common than might be obvious at first blush.
A Poster He or I wrote: Anyway, I'm still scratching my head a bit regarding your statement that "No theory of mechanics can be accommodated within the paradigm of spacetime, which is an action-at-a-distance model. This foundational assumption is false." It seems pretty obvious that mechanics is not only accommodated by spacetime, it requires spatio-temporal extension/duration to even be sensible. I feel what you mean to say is that mechanics does not define spacetime (that is, it tells us nothing about the ontological status of spacetime, and epistemologically it merely catalogs spacetime's behavior without telling us how it qualifies as an epistemic object).
Spacetime replaces the physical space of Newton with a geometric analogue, which makes the last sentence of this quote the operative one. Geometry is a mathematical tool, not a physical state of being, thus when physicists tell us that light follows the geometry of a curved space, in gravitational lensing for instance, they are not making a physical statement but a mathematical one. In order to make such a statement physical they would need to offer a mechanical explanation for how empty space can bend light. They can't do this because the spacetime paradigm is not designed to do this. It is in that sense that I say that spacetime is non-mechanical, or action-at-a-distance. Einstein was well aware of this,as was Bohr, and they both took pains throughout their lives to stress that spacetime was to be regarded as an "as if" paradigm, rather than an ontologically valid one.

I get the feeling we are in agreement on this but a century down the track this message somehow seems to have got lost, even by many physicists themselves.

You'll never hear me downplaying the significance of these models in terms of their predictive power but as long as I draw breath I'll continue to maintain that they have no explanatory authority.

Regards Leo

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Re: Magnetism - distilling the everyday from the extraordina

Post by Steve3007 » June 5th, 2014, 5:19 am

Leo and A Poster He Or I:

I'm glad that you two are talking. Ever since Leo joined the forum and expressed his ideas about the importance of Ontology I thought it would be interesting to get Poster's comments, given his own views on that particular philosophical concept.

I will just say that, as a broad principle, I tend to come down more on the side of Poster's views about the roles of such things as ontology, epistemology and possibly some other ologies, as exemplified by such past statements (by Poster) as these:
Scientists ... spend their efforts exposing and systematizing the relations between phenomena, in accordance with scientific epistemology; an epistemology that consciously allows itself (albeit reluctantly) to evolve based on its own discoveries.
Just as we have multiple, incompatible models of gravity, electromagnetism, prismatics, etc. One chooses the appropriate model based on what one seeks to achieve.
I believe very much in reality. I just consider any objective ontology for reality (if there even is such a thing) to be irrelevent since the entire apprehension of reality is via subjective experience that cannot recognize objectivity since it has only its own subjective experience to decide what constitutes "objective."
with which I broadly agree.

Having said that, I suspect, as I've recently said on another thread, that I also agree with Leo on a lot of things but just use different language to express it, so the disagreement appears bigger than it really is. I think the linguistic disagreement between the views of Poster and myself on the one "side" and Leo on the other are perhaps exemplified best when Leo says this:
You'll never hear me downplaying the significance of these models in terms of their predictive power but as long as I draw breath I'll continue to maintain that they have no explanatory authority.
I would ask once again: what exactly is this supposed fundamental difference between explanatory authority and descriptive/predictive authority? On what basis would you claim that any model that you might propose has explanatory authority?

On other threads, you've proposed a model that you think might resolve the incompatibility between the Standard Model and General Relativity. Fine. If it can do that, then that would be wonderful. But that doesn't make it fundamentally different from previous models. It just means that it purports to encompass a wider set of possible observations than they do. It encompasses them and adds to them. They then become a special case of it. Just as General Relativity did with Newton's Universal Theory of Gravitation.

Another interesting example of our differences:
Spacetime replaces the physical space of Newton with a geometric analogue, which makes the last sentence of this quote the operative one. Geometry is a mathematical tool, not a physical state of being, thus when physicists tell us that light follows the geometry of a curved space, in gravitational lensing for instance, they are not making a physical statement but a mathematical one. In order to make such a statement physical they would need to offer a mechanical explanation for how empty space can bend light.
In saying that light does this, it is true that they are not making a direct statement about a physical observation. But in order to make it so, I don't think they need to offer a mechanical explanation as to how space can bend, as you put it. I think they simply have to show how their mathematical statements lead to predictions of observations. In the case of gravitational lensing, by, for example, doing something similar to the measurements that were done during the solar eclipse in 1919.

So, I don't accept your distinction between the "as if" model and the "is" model. We're back to ducks again! As far as I'm concerned, any creature that looks and behaves in all respects "as if" it were a duck, "is" a duck in every sense that can possibly matter.

---

P.S. I've now, finally, started a new thread on this subject of explanation versus description. Hopefully that will help to eliminate the duplication and waste of effort involved in having to discuss this over several different threads.
"When the seagulls follow the trawler, it is because they think sardines will be thrown into the sea." - Eric Cantona.

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Re: Magnetism - distilling the everyday from the extraordina

Post by A Poster He or I » June 5th, 2014, 1:59 pm

(Did I really say all those things at some point? Wow, no wonder I agree with them) :wink:

I agree with Steve's assessment of our differences with Leo. To repeat myself, it seems that Leo is targeting theory per se as the bogeyman for somehow not doing its full job, which is confusing me because he also states his agreement that ontology has no place in theoretical physics.

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Re: Magnetism - distilling the everyday from the extraordina

Post by Obvious Leo » June 5th, 2014, 7:29 pm

A Poster He or I wrote:(Did I really say all those things at some point? Wow, no wonder I agree with them) :wink:

I agree with Steve's assessment of our differences with Leo. To repeat myself, it seems that Leo is targeting theory per se as the bogeyman for somehow not doing its full job, which is confusing me because he also states his agreement that ontology has no place in theoretical physics.
Just a slight misunderstanding I think, mate. Theory is doing its full job in that theory does exactly what it is designed to do, make predictions about the behaviour of matter and energy. My bitch is with those who seek to make epistemology do what it not designed to do, namely provide the ontological underpinning for such behaviour. I'm pretty sure we're saying the same thing.

Regards Leo

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Re: Magnetism - distilling the everyday from the extraordina

Post by Voidance » October 26th, 2016, 3:22 pm

Saying a moving electric field creates magnetism seem a little like saying stationary water is just water but once it moves it becomes something else which isn't water.

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Re: Magnetism - distilling the everyday from the extraordina

Post by Rainman » November 2nd, 2016, 2:13 pm

Forces that "push" are forces I can understand. If the Observable Universe is just matter/energy banging around into each other then I can understand "pushes" because stuff banging into other stuff cause other stuff to move. "Pulls" are something else entirely. I don't know how or when but, to make sense to me, sooner or later science will see magnetism and gravity as pushes. The pushes will have to come from "stuff" that is a way way smaller than what we can currently observe. Maybe a kind of dark matter. But, to me, physical pushes make sense but pulls...not so much. Maybe if I were a barmaid, then I'd understand.

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Re: Magnetism - distilling the everyday from the extraordina

Post by Dolphin42 » November 3rd, 2016, 4:11 am

Rainman: Why do you find forces that push - objects bouncing off each other - to be more naturally easy to understand? Why don't you expect objects to pass right through each other? Conversely, if you have less intuitive trust in the idea of forces that pull, why don't you expect all objects to fall apart into a mist of tiny particles?

-- Updated November 3rd, 2016, 9:15 am to add the following --

Voidance:
Saying a moving electric field creates magnetism seem a little like saying stationary water is just water but once it moves it becomes something else which isn't water.
It's not saying that electric fields turn into something else. All it's saying is that electricity and magnetism are the same thing seen from different viewpoints. That thing is electromagnetism.

-- Updated November 3rd, 2016, 9:18 am to add the following --

A bit like the fact that the evening star and the morning star are the same thing seen at different times of day. The planet Venus.

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Re: Magnetism - distilling the everyday from the extraordina

Post by Rainman » November 3rd, 2016, 4:43 pm

[quote="Dolphin42"]Rainman: Why do you find forces that push - objects bouncing off each other - to be more naturally easy to understand? Why don't you expect objects to pass right through each other? Conversely, if you have less intuitive trust in the idea of forces that pull, why don't you expect all objects to fall apart into a mist of tiny particles?"

For the same reason it would be hard for me to push through a room full of bowling balls. The more densely packed the bowling balls...that harder it is to push through them. So...the more densely packed the "stuff" in the universe is...the harder it would be for anything to move through them. When you say why I don't intuitively trust pulls...it's because I don't understand how that would work in a universe filled with moving "stuff". The stuff doesn't pull apart because it is being pushed together by other...maybe very tiny...stuff. So I guess I'm saying that gravity is just a push from...maybe...tiny black matter that we can't see.

I like to think of the universe as being very simple...an infinitely large universe filled with "stuff" that moves around in predictable ways. Everything moves because there are empty spaces between the "stuff". The empty spaces allow the stuff to move. I think, probably, the "stuff" can be infinitely small but that is too philosophical.

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Re: Magnetism - distilling the everyday from the extraordina

Post by Dolphin42 » November 4th, 2016, 2:50 am

Rainman, your view of the world seems unnecessarily complicated and messy to me.
Dolphin42 wrote:Why don't you expect objects to pass right through each other?
Rainman wrote:For the same reason it would be hard for me to push through a room full of bowling balls.
Obviously that just begs the question: Why can't you pass right through each of those little bowling balls? If I ask why solid objects, like, for example, bowling balls, don't pass right through each other and you say that it's because they're made of little bowling ball-like objects, it doesn't really seem like much of an explanation.
Rainman wrote:The stuff doesn't pull apart because it is being pushed together by other...maybe very tiny...stuff.
OK. So the reason solid objects don't fall apart is not because of the electrostatic attraction/pull between their constituent atoms but because they are surrounded by other stuff that squeezes them together. Fair enough, but you then say:
Rainman wrote:Everything moves because there are empty spaces between the "stuff". The empty spaces allow the stuff to move.
That seems to contradict the earlier idea. If a solid object is floating in empty space and is not surrounded by this other invisible stuff to hold it together it should immediately fall apart. If, even in empty space, it is surrounded by this other stuff then, by your argument, its motion should be noticeable resisted. Neither of these things are observed to happen.

I think it's simpler just to stick with the idea that forces can push and pull. In general, we tend to find ideas complex and counter-intuitive if we're not familiar with experiencing them every day. But I do experience pushing and pulling every day. I guess it's down to personal taste. Put when I pull on a rope, if I think about it at all, I find it much easier to envisage the atoms that make up that rope being separated slightly with a resultant electrostatic attraction pulling them back together than to imagine some kind of invisible stuff pushing on the ends of the rope, or something.

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Re: Magnetism - distilling the everyday from the extraordina

Post by Rainman » November 5th, 2016, 11:45 am

re."That seems to contradict the earlier idea. If a solid object is floating in empty space and is not surrounded by this other invisible stuff to hold it together it should immediately fall apart. If, even in empty space, it is surrounded by this other stuff then, by your argument, its motion should be noticeable resisted. Neither of these things are observed to happen."

But that's just the problem. Objects in space do seem to have noticeable forces acting upon them that we don't understand. Thus the creation of "dark matter" and "dark energy" models. It points to empty space not being empty...just not observable with today's technology. To my mind, space is more like a thick stew than a thin soup. There is more "stuff" banging around out there than we can presently observe.

re: "I think it's simpler just to stick with the idea that forces can push and pull. In general, we tend to find ideas complex and counter-intuitive if we're not familiar with experiencing them every day. But I do experience pushing and pulling every day. I guess it's down to personal taste. Put when I pull on a rope, if I think about it at all, I find it much easier to envisage the atoms that make up that rope being separated slightly with a resultant electrostatic attraction pulling them back together than to imagine some kind of invisible stuff pushing on the ends of the rope, or something."

That's my current conundrum...how to explain the contraction/expansion of an elastic band as a push not a pull. I don't have enough of an understanding as to how "stuff" below the size of quarks and even smaller bits interact. I'm stuck with the concept of "energy" being able somehow to pull "stuff" as being a more predictive theory.

-- Updated November 5th, 2016, 12:22 pm to add the following --

Muscles pulling ropes and rubber bands contracting seem to involve the concept of entropy. Forcing the resting state of the rubber band into a more ordered, unnatural state of elongation seems to obviously be a "pull". But if you saw the same rubber band changing shape in the same way while the rubber band was floating alone in outer space, then it would a lot harder to determine if it was being pushed or pulled out of shape. In the same way, we don't know that much about what goes on in the sub-molecular realm. Things that seem obviously as "pulls" could be "pushes" at that level. Who knows what a rubber band in motion might look like at the sub-molecular level?

Gravity being a "pull" just doesn't sit right with me. I think dark matter pushing planets and stars together makes more sense but only in a philosophical way...not a scientific, experimental proof way.

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