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Is physics about "why?"


newts
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Why must you presume to know who my colleagues even are? Why does that even matter in the least? How does this address any of the concerns brought up to you?

 

If you had said which current theories you believe to be correct, which wrong and which dodgy, that would have been interesting. It would also be interesting if you would explain why you do not share your opinions. Merely taking offence at whatever I post, not so interesting.

 

Do you want me to do the calculation?

As you know, special relativity is deemed to give the same results as the Lorentz aether theory. What I would like you to do is explain magnetism using LET, for the special case where the earth is stationary in the aether. Then I can evaluate what the theory actually means, no calculations needed at this stage.

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If you had said which current theories you believe to be correct, which wrong and which dodgy, that would have been interesting. It would also be interesting if you would explain why you do not share your opinions. Merely taking offence at whatever I post, not so interesting.

Wow, another bunch of words that seems to have nothing to do with the post it's responding to. Are you ever going to respond to the papers cited?

As you know, special relativity is deemed to give the same results as the Lorentz aether theory. What I would like you to do is explain magnetism using LET, for the special case where the earth is stationary in the aether. Then I can evaluate what the theory actually means, no calculations needed at this stage.

You are asking me to explain using a theory that I don't use. Not my job. You can feel free to ask me to explain relativity; that is where my experience lies.

 

I like how you decided not to respond to all of the other parts of my post. No explanation of "obviously" or "illogical". Are you ever going to explain?

=Uncool-

Edited by uncool
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As you know, special relativity is deemed to give the same results as the Lorentz aether theory. What I would like you to do is explain magnetism using LET, for the special case where the earth is stationary in the aether. Then I can evaluate what the theory actually means, no calculations needed at this stage.

 

!

Moderator Note

That's not the topic of this thread, and is only the job of someone advancing LET as a valid theory. Which they can do in a different thread.

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No, what I would say is that Feynman could not explain magnetism because he did not really understand it, but it is an interesting clip. I do admire Feynman, he understood a lot and did his best to share his understanding; unlike today’s celebrity physicists who understand little, and try to mysticise the universe.

So you're saying one of the founders of quantum electrodynamics doesn't understand electromagnetism? And that doesn't seem a stretch to you.

 

Also, he had an entire aside about how asking why tends to be basically useless.

Given physicists’ current understanding, it would seem reasonable to say that electrons repel each other and attract positrons, merely because it is in their nature to do this. But clearly magnetism is not a fundamental force. Lay 2 wires side by side, there is negligible force between them, pass currents in the same direction the wires attract, pass currents in opposite directions they repel. These forces are described as magnetic, therefore at least some magnetic forces must be caused by electric currents or the motion of electrons. It also inclines me to think that, contrary to popular belief, magnetic forces should really be described as like attracting like, and repelling unlike.

 

Is anybody interested in the cause of magnetism, or is that too mundane for modern physicists?

So like attracts like, despite evidence to the contrary? That's not really asking why, that's just making things up.
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newts, on 07 May 2013 - 18:38, said:

If you had said which current theories you believe to be correct, which wrong and which dodgy, that would have been interesting. It would also be interesting if you would explain why you do not share your opinions. Merely taking offence at whatever I post, not so interesting.

More than anything, newts, I'm really not sure what twisted definition of 'correct' or 'incorrect' you'll apply. Your record on this manner is speckled at best.

 

However, overall my position has been very clear (especially if you look through my history of posts), that I support the model that proves to be the most useful. And I define useful as how well the predictions made by that model agree with measurements.

 

In this vein, I do often write that we know our models today are wrong or at least incorrect. This statement is backed in 2 ways: history has shown time and time again that better models are almost always created and we know that our current models are limited. The best example is the lack of unified model of quantum mechanics and general relativity. We seen to have decent models for the really small and the really large, but nothing that bridges both of them. Therefore, we know the current models are wrong in that they are at least incomplete.

 

We also know that the current models are right in that when applied to the correct domain and conditions, they make really quite good predictions. And whatever future model that is out there will make even better predictions.

 

In my mind, the model that makes the best predictions is the best.

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So you're saying one of the founders of quantum electrodynamics doesn't understand electromagnetism? And that doesn't seem a stretch to you.

 

Also, he had an entire aside about how asking why tends to be basically useless.

 

 

Maybe you consider Feynman to be so great, that you have to accept the literal truth of everything he says? It is perhaps pointless to ask why the universe exists, and only a fantasist like Hawking would consider that a question of physics.
Asking why things burn is not pointless. A couple of hundred years ago people like yourself would have been convinced it was explained by phlogiston, and would have been upset to hear phlogiston described as an imaginary being. Nowadays we know that burning just involves electrons and atomic nuclei rearranging themselves and emitting photons, which is such a sound theory that it is universally accepted by the most sceptical as well as people of all religions. It is only pointless to ask why, if the question can never be answered.
People asked why Kepler’s laws worked. Newton answered this with his mechanics and gravity. People asked what caused gravity; after much thought Newton could not find an answer, so he declared the cause of gravity had no place in experimental philosophy. Newton’s scorn for seeking a cause for gravity is well placed when applied to gravitons, as inventing imaginary beings which make no testable predictions, is the stuff of religion not physics. But some theories of gravity do make testable predictions, such as Le Sage gravity which makes wrong predictions.
Feynman must have spent hundreds of hours trying to come up with a theory to explain the predictions of QED. It was only when he failed that he concluded it was pointless. He might be right, and thinking up such a theory might exceed the capacity of the human mind, but it might not.

 

So like attracts like, despite evidence to the contrary? That's not really asking why, that's just making things up.

You see the phrase “contrary to popular belief”, and translate it as “despite evidence to the contrary”. I guess that is standard behaviour for a physics-believer, and indeed most humans. If currents both going in the same direction attract, and currents going in opposite directions repel, that could be seen as like attracting like, and opposites repelling. Is that really such a difficult concept to understand?

I like how you decided not to respond to all of the other parts of my post. No explanation of "obviously" or "illogical". Are you ever going to explain?

 

Obviously you know that Maxwell figured out the maths of magnetism 50 years before the advent of SR. Illogical because you are seeking to explain the magnetic field, something which has mass, in terms of reference frames which do not have mass.

Edited by newts
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Obviously you know that Maxwell figured out the maths of magnetism 50 years before the advent of SR.

So "obviously" meaning that the person who came up with the explanation would know the relation between the current and the magnetic field?

Illogical because you are seeking to explain the magnetic field, something which has mass, in terms of reference frames which do not have mass.

This sentence makes no sense. Please try again.

=Uncool-

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Maybe you consider Feynman to be so great, that you have to accept the literal truth of everything he says? It is perhaps pointless to ask why the universe exists, and only a fantasist like Hawking would consider that a question of physics.

I think he was a great speaker and a great physicist, yes. Do I agree with everything he says? Not at all. So starting from a false premise will get you no where.

Asking why things burn is not pointless. A couple of hundred years ago people like yourself would have been convinced it was explained by phlogiston, and would have been upset to hear phlogiston described as an imaginary being. Nowadays we know that burning just involves electrons and atomic nuclei rearranging themselves and emitting photons, which is such a sound theory that it is universally accepted by the most sceptical as well as people of all religions. It is only pointless to ask why, if the question can never be answered.

You're confusing why and how. Phlogiston and the like are not explanations of why things burn, it's how they burn. Why tends to be an ultimate cause, how tends to be the mechanisms. You are describing mechanisms, not ultimate causes.

Peop

le asked why Kepler’s laws worked. Newton answered this with his mechanics and gravity. People asked what caused gravity; after much thought Newton could not find an answer, so he declared the cause of gravity had no place in experimental philosophy. Newton’s scorn for seeking a cause for gravity is well placed when applied to gravitons, as inventing imaginary beings which make no testable predictions, is the stuff of religion not physics. But some theories of gravity do make testable predictions, such as Le Sage gravity which makes wrong predictions.

Again, you're not doing "why"s you're doing "how"s.

Feynman must have spent hundreds of hours trying to come up with a theory to explain the predictions of QED. It was only when he failed that he concluded it was pointless. He might be right, and thinking up such a theory might exceed the capacity of the human mind, but it might not.

Citation needed.

You see the phrase “contrary to popular belief”, and translate it as “despite evidence to the contrary”. I guess that is standard behaviour for a physics-believer, and indeed most humans. If currents both going in the same direction attract, and currents going in opposite directions repel, that could be seen as like attracting like, and opposites repelling. Is that really such a difficult concept to understand?

Can you guess how something becomes popular belief in science? Evidence. So the phrases, in a scientific context, are equivalent.

 

Currents going in the same direction attract due to the direction of the field around the wire, which are in different direction on opposite sides of the wire. Do you think that the field generated is universal in its direction?

Edited by Ringer
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Wow, another bunch of words that seems to have nothing to do with the post it's responding to.

I am sorry words cause you so much distress, so to ease your affliction I have drawn you a picture.

 

post-44292-0-22145300-1368236517_thumb.jpg

Edited by newts
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I am sorry words cause you so much distress,

What?

so to ease your affliction I have drawn you a picture.

 

attachicon.gifuncool.jpg

Congratulations; you've drawn a picture. Please, next time write the text out so it can be quoted.

 

First, "If we move the whole set-up in the second diagram to the left at 1 m/s, we get the third diagram" is false. The third diagram has the lone electron show no movement towards the wire (as you've said that it's the same as the first diagram with the nuclei moving to the left instead of the electrons moving to the right), but you labeled the second diagram with the electron moving towards the wire.

 

Second, "The only difference between the third diagram and the first is that the protons are moving to the left instead of the electrons moving to the right" is false, for two reasons. It neglects the linear density of charges. Unless you want to assume Galilean relativity, which would negate the point of the exercise entirely.

 

Third, the final statement doesn't follow. Please try to explain your logic again.

=Uncool-

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You're confusing why and how.

Why is it that people here are so reluctant to discuss physics, and only seem to want to argue about the meaning of words? Or should that be “How is it that people here are so reluctant to discuss physics, and only seem to want to argue about the meaning of words?”

 

First, "If we move the whole set-up in the second diagram to the left at 1 m/s, we get the third diagram" is false. The third diagram has the lone electron show no movement towards the wire (as you've said that it's the same as the first diagram with the nuclei moving to the left instead of the electrons moving to the right), but you labeled the second diagram with the electron moving towards the wire.

In the first diagram the electron does not move towards the wire, in the second and third it does. Do you agree?

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Why is it that people here are so reluctant to discuss physics, and only seem to want to argue about the meaning of words?

Because we use words to communicate, and so using the wrong words means being unable to communicate.

 

You are crowing about people saying that they cannot answer "why," when they can (and have) answered "how." So people are pointing out that they have given at least as much justification as you have.

Or should that be “How is it that people here are so reluctant to discuss physics, and only seem to want to argue about the meaning of words?”

 

In the first diagram the electron does not move towards the wire, in the second and third it does. Do you agree?

That's your choice, since it's your picture. But if that's true, then "But the only difference between the third diagram and the first is that the protons are moving to the left instead of the electrons moving to the right" is wrong for two separate reasons.

 

Once again, I'm offering to do the calculation. Do you want me to or not?

=Uncool-

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Why is it that people here are so reluctant to discuss physics, and only seem to want to argue about the meaning of words? Or should that be “How is it that people here are so reluctant to discuss physics, and only seem to want to argue about the meaning of words?”

I would have to guess, and keep in mind that this is just a wild guess, it's because the entire point of this thread is a discussion of the difference between if physics is about 'why' or 'how'. Or is the difference of why and how in a thread named 'is physics about why' somehow off topic?
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That's your choice, since it's your picture.

Once again, I'm offering to do the calculation. Do you want me to or not?

 

Even though the experiments cannot be performed exactly as I described, you should still be able to judge what the results would be.
Diagram 1 involves a wire and an electron both stationary relative to the lab. In diag 2 the electron moves relative to the lab. In diag 3 the whole experiment in 2 is put on a conveyor belt. Alternatively the observer could have been put on a conveyor belt and moved to the right at 1 m/s.
It is a yes/no question as to whether the electron accelerates towards the wire. The force cannot be calculated as I have not specified the number of moving electrons in the wire.

 

I would have to guess, and keep in mind that this is just a wild guess, it's because the entire point of this thread is a discussion of the difference between if physics is about 'why' or 'how'. Or is the difference of why and how in a thread named 'is physics about why' somehow off topic?

The original thread was about whether a physics hypothesis could be expressed in words rather than maths. I argue that a proper theory can always explain why, or how, things happen, in words; and that if all that is available is a mathematical formula that makes predictions, that is a sign of human ignorance not a sign that the universe is mysterious and mystical. In this regard using the word ’how’ rather than ’why’ is neither here nor there.

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I argue that a proper theory can always explain why, or how, things happen, in words; and that if all that is available is a mathematical formula that makes predictions, that is a sign of human ignorance not a sign that the universe is mysterious and mystical.

And I disagree in the strongest terms.

 

Using only words, describe how a golf ball sitting on a tee flies exactly 207.7 yards downrange. And I require that in using your words, that is it obvious that the prediction is 207.7 yards, and not 208.7 or 206.7 yards.

 

If all you want is a 'words' description of what the equations are saying, those are out there. But words will never make as good a prediction as math. I just don't see how you think it can.

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Even though the experiments cannot be performed exactly as I described, you should still be able to judge what the results would be.

Not necessarily as easily as you claim. Which is why I'm offering to do the calculation.

 

Diagram 1 involves a wire and an electron both stationary relative to the lab. In diag 2 the electron moves relative to the lab. In diag 3 the whole experiment in 2 is put on a conveyor belt. Alternatively the observer could have been put on a conveyor belt and moved to the right at 1 m/s.
It is a yes/no question as to whether the electron accelerates towards the wire. The force cannot be calculated as I have not specified the number of moving electrons in the wire.

It can be calculated in terms of current, by letting the charge density be a variable.

 

It may be a yes/no question, but it still involves calculation. So I am offering to do the calculation. Do you want it or not?

 

I argue

No, you don't. You proclaim such.

=Uncool-

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The original thread was about whether a physics hypothesis could be expressed in words rather than maths. I argue that a proper theory can always explain why, or how, things happen, in words; and that if all that is available is a mathematical formula that makes predictions, that is a sign of human ignorance not a sign that the universe is mysterious and mystical. In this regard using the word ’how’ rather than ’why’ is neither here nor there.

Wait, you're saying that words can suffice to explain everything. Yet not two posts ago you were complaining about arguing over the meanings of words. Can you really not see why words aren't that great at truly explaining things?
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And I disagree in the strongest terms.

 

Using only words, describe how a golf ball sitting on a tee flies exactly 207.7 yards downrange. And I require that in using your words, that is it obvious that the prediction is 207.7 yards, and not 208.7 or 206.7 yards.

 

If all you want is a 'words' description of what the equations are saying, those are out there. But words will never make as good a prediction as math. I just don't see how you think it can.

 

As Ringer says, words have their limitations but so does maths. Your question is meaningless unless somebody knows what a yard is. The easiest way to do this would be to show them a 1 yard stick, but you would still need to tell them in words. Using maths to explain a yard would be impossible unless they already knew what say an inch was.
In the absence of air, the distance flown would be calculated by balancing the vertical component of the velocity with gravity to calculate the time of flight, and then assuming the horizontal component of the velocity remains constant. That is a principle which needs to be explained in words not mathematical symbols.
Given the same data, we would calculate the same distance in a similar manner, so we agree on the physics. I am still having to argue about abstract ideas, can I not interest you in the magnetism question? I think Uncool is avoiding the issues, and all he really wants to do is a SR calculation to get some more green marks from fellow relativity-believers; but don’t tell him I said so.
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Given the same data, we would calculate the same distance in a similar manner, so we agree on the physics. I am still having to argue about abstract ideas, can I not interest you in the magnetism question? I think Uncool is avoiding the issues, and all he really wants to do is a SR calculation to get some more green marks from fellow relativity-believers; but don’t tell him I said so.

You may want to quit your day-job as a mind-reader. You are truly atrocious at it.

 

I'm offering to do the calculation because you are claiming to want to know what relativity says. You are the one asking what would happen under certain circumstances; I am offering to do the calculation for you. If you don't want the answer to the question you asked, just say so. If you are interested, all you have to do is say yes, and I will do the calculation, including my best attempt to translate it back into words.

=Uncool-

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Your question is meaningless unless somebody knows what a yard is. The easiest way to do this would be to show them a 1 yard stick, but you would still need to tell them in words. Using maths to explain a yard would be impossible unless they already knew what say an inch was.

Heck, maybe we really need to start with 1 + 1 = 2 and build from there.

 

newts, a certain level of mathematical understanding is to be assumed. Also assumed is that the people asking and answering questions agree upon a set of units of measure. If this is really the nit you have to pick with my comment, you are completely missing the point.

 

Which I will re-write here for emphasis: no matter how good someone's writing is, words alone cannot make as good a prediction as mathematics in almost every case. If you disagree, I again challenge you use words alone to make predictions on how far golf balls will be hit. Using those words, the prediction should have a margin of error less than a single yard.

 

In the absence of air, the distance flown would be calculated by balancing the vertical component of the velocity with gravity to calculate the time of flight, and then assuming the horizontal component of the velocity remains constant. That is a principle which needs to be explained in words not mathematical symbols.

But this isn't a prediction!!!! This doesn't discriminate between 206.7, 207.7, or 208.7 yards. The words may explain the principle, but how would one judge the accuracy and usefulness of that explanation. Using math, I would compare the prediction to the measurement and have an objective, clear cut metric on just how good the prediction was. Using just words, you just give that away. Why would anyone want to do that?
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