Charge

[protonman]

Why do like charges repel and opposite charges attract?

[chroot]

Because, according to Coulomb's law,

F = \frac{1}{4 \pi \epsilon_0} \frac{q_1 q_2}{R^2}

the charges are multiplied together. When their signs are the same, the force is positive, representing a repulsion. When their signs are opposite, the force is negative, representing an attraction.

- Warren

[protonman]

Because, according to Coulomb's law,

F = \frac{1}{4 \pi \epsilon_0} \frac{q_1 q_2}{R^2}

the charges are multiplied together. When their signs are the same, the force is positive, representing a repulsion. When their signs are opposite, the force is negative, representing an attraction.

- WarrenThat doesn't answer the question. Anyone can observe that they do behave as I asked and make up an equation to show that. What I am asking is a more physical explanation.

[chroot]

What you're asking for is not a physical explanation; you're asking for a philosophical explanation. No one knows why there happen to be two kinds of electric charge (instead of four or nineteen) or why they work as they do. Even if one day a theory does present a logical reason for such behavior, we'll have to question the reasons why that theory exists, and so on, ad infinitum. Eventually, at a deep enough level, we'll just have to be assuaged with one of two beliefs:

1) It just is that way, and there's no deeper reason.
2) God, or some other sentient being, chose for it to be that way.

Personally, I'd just invoke the anthropic principle and not worry about it anymore.

- Warren

[protonman]

What you're asking for is not a physical explanation; you're asking for a philosophical explanation. No one knows why there happen to be two kinds of electric charge (instead of four or nineteen) or why they work as they do. Even if one day a theory does present a logical reason for such behavior, we'll have to question the reasons why that theory exists, and so on, ad infinitum. Eventually, at a deep enough level, we'll just have to be assuaged with one of two beliefs:

1) It just is that way, and there's no deeper reason.
2) God, or some other sentient being, chose for it to be that way.

Personally, I'd just invoke the anthropic principle and not worry about it anymore.

- WarrenWhat if Einstein just decided to "not worry" about the incompatibility between Maxwell's equations and Galilean relativity? You thinking is surprising for a scientist.

[chroot]

That's quite a different worry.

- Warren

[protonman]

Personally, I'd just invoke the anthropic principle and not worry about it anymore.Strong or weak anthropic principle?

[protonman]

That's quite a different worry.

- WarrenHow is this?

[chroot]

When we have two mathematically-developed theories that disagree, something is obviously wrong with one or both of those theories. That prompts us to do more experimentation, to determine where and how the theories fail.

In contrast, when we have one mathematically-developed theory that produces valid predictions for all known experiments, we go home and sleep easy -- that's all we intended to do. We don't generally care too much about the philosophy of WHY that particular theory is correct, since it's pretty much a rhetorical question.

- Warren

[protonman]

We don't generally care too much about the philosophy of WHY that particular theory is correct, since it's pretty much a rhetorical question.The term "we" in your quote is quite strong. Do you speak for all physicists?

[chroot]

Not for all, I'd imagine -- but certainly for the vast majority.

- Warren

[protonman]

Not for all, I'd imagine -- but certainly for the vast majority.

- WarrenHow do you come to this conclusion?

[chroot]

I read the things other physicists write. I converse with other physicists.

- Warren

[protonman]

I read the things other physicists write. I converse with other physicists.

- WarrenHave you read the writings of the vast majority?

[protonman]

You are not even a physicist. I want to hear from a physics expert not an engineer.

[chroot]

Sure thing, ask around.

- Warren

[Integral]

Warren,
You seem to be on the right track as far as I know. I think few Physicts would argue with you.

Protonman,
What is your point? Have you ever spoken to ANY physicists?

[protonman]

Warren,
You seem to be on the right track as far as I know. I think few Physicts would argue with you.

Protonman,
What is your point? Have you ever spoken to ANY physicists?First of all you can't speculate what the majority of physicists would say. As someone who claims to be involved in science it seems strange you would present something like that without evidence.

Second, I spent plenty of time with physicists and I have listened to many. From my personal experience your view does not represent the views of those scientists I have had encounters with.

[Nereid]

What views have they expressed to you?

[Integral]

First of all you can't speculate what the majority of physicists would say. As someone who claims to be involved in science it seems strange you would present something like that without evidence.

Second, I spent plenty of time with physicists and I have listened to many. From my personal experience your view does not represent the views of those scientists I have had encounters with.
Without a doubt you were hearing exactly what you wanted to hear without understanding a word that was said.

It would be interesting to hear more of the details.

Oh yeah, I spent 8 yrs working in the Physics department of a major research university. So, yes, I have spent some time around Physicists, both professionally and personally (ie around a keg of beer).

[hellfire]

I do not remember exactly the details, but I remember have read in the first chapters of Zee ‘Quantum Field Theory in a Nutshell’ that opposite charges repel for odd-spin fields and attract for even-spin fields. The propagator of the electromagnetic force, the photon, has spin 1. This would be at least a partial answer to the question.

Regards.

[protonman]

What views have they expressed to you?Many views.

[protonman]

Oh yeah, I spent 8 yrs working in the Physics department of a major research university. Who cares that is still only a few professors and staff. One university does not constitute the physics community. In fact, even within a community you are likely to get a divergence of opinion.

So, yes, I have spent some time around Physicists, both professionally and personally (ie around a keg of beer).Oh boy you are so cool.

[protonman]

I do not remember exactly the details, but I remember have read in the first chapters of Zee ‘Quantum Field Theory in a Nutshell’ that opposite charges repel for odd-spin fields and attract for even-spin fields. The propagator of the electromagnetic force, the photon, has spin 1. This would be at least a partial answer to the question.

Regards.And it only took this long to get a reasonable answer. This is a good start.

[Nereid]

Many views.Would you be so kind as to elaborate?

[Nereid]

First of all you can't speculate what the majority of physicists would say. As someone who claims to be involved in science it seems strange you would present something like that without evidence.

Second, I spent plenty of time with physicists and I have listened to many. From my personal experience your view does not represent the views of those scientists I have had encounters with.On the surface, this would seem to be a fairly straight-forward thing to research. For example, using the techniques of market research (tho' I rather doubt that YouGov or Pew have ever done such a survey :tongue: ).

Perhaps those who are familiar with HPS could help here? PF's own Hugo Holbling might be able to immediately quote half a dozen papers written on the subject (for example).

However, I have this sneaking suspicion that protonman has cast aside but the first veil. :cool: