Re: Physical interpretation in physics.


"Jeckyl" <noone@xxxxxxxxxxx> wrote in message
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"harry" <harald.vanlintelButNotThis@xxxxxxx> wrote in message
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"harry" <harald.vanlintelButNotThis@xxxxxxx> wrote in message
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Yes indeed - rotation relative to what?

Any inertial frame in which the centre of rotation is at rest

Nice try. :-)

Pretty much perfect

Relative to what do you think that "inertial frames" are not
rotating?

Every other inertial frame

I can give you a similar answer: they are not rotating relative to
Newtonian frames!

Rotation is absolute .. independent of the iFoR in which it is
measured
Acceleration is absolute .. independent of the iFoR in which it is
measured
Velocity is not.

Only iFoR really count, because they are the FoR where the laws of
physics apply uniformly and consistently.
Consistency ain't the issue.
If the 'laws' dont appl consistently, they aren't laws.
Indeed. It ain't an issue.

Yes .. consistency is. If the results and predictions are not consistent,
then there is no more physics.

Here's another consistent one: God exists because it's written in the
bible and the bible must be true because in it God says that the bible
is inspired by him. ;-)
Nonsense
Exactly - consistent but that's not the issue. :-)

Consistent is not sufficient .. I didn't say it was .. but it is
necessary. Do you know the difference between necessary and sufficient
conditions?

I already tried to explain that to you. Nonsense can be perfectly
consistent. That's not the problem.

iFoR can be virtual in which case they can have no physical effect.
What do you mean 'can be' .. they aren't physical to begin with.
The most classical (nearly) inertial frame by Galileo is a ship that
sails a steady course at sea. That's very physical.

No .. he ship is physical .. the frame of reference is a concept

A ship can serve as a frame of reference but what we commonly mean with it
is a construct of the mind - and we agree on that, it's not constructive to
pretend to disagree on what you already made clear to agree with.

There is no framework out there .. there doesn't need to be any actual
object that htey are associated with. They are a concept.
Exactly. Concepts of the mind can't physically affect you - except
perhaps if you believe in telekinesis. :-)

Who said they did? That's really the point.. if you are at rest wrt some
frame of reference and I am at rest wrt some different frame of reference,
then there is no physical effect on us from that. The same laws of
physics apply.

The point that Newton made was that you can also choose a frame of reference
that is rotating relative to it; and other laws of physics apply.

The concepts of the mind can model what is physical .. and they do very
nicely.

Sure.

Why is it you have a problem with intertial frames of reference .. did you
miss the lecture on that?

In fact you didn't understand my lecture to you on that - which was a retake
of those of Newton, Mach and Einstein. :-)

The question was about the physical cause that makes them look special
or "preferred".
There is none .. there doesn't need to be one .. because they aren't
physical.
Then let's get back to your explanation, and substitute the appropriate
words according to your own clarification:

Summarizing the conversation:

Maxwell:
"Newton's bucket demonstrates the absolute nature
of relative rotation (bucket relative to the local 'fixed stars')"
Harald:
Yes indeed - rotation relative to what?
Jeckyl:
Any inertial frame in which the centre of rotation is at rest.
They aren't physical.

But the location of the centre of the rotation is a physical location.
And the motion is relative to that.

There is no motion relative to a co-rotating frame.

If you like, pick another object that is at rest relative to the center of
rotation. Then you can get the roation relatie to the line joining those
points.

See above - the centre of rotation wasn't the issue that Newton and Mach
discussed.

The choice seems to be between Newton/Lorentz and Mach, or as Einstein
attempted, a bit of both - he fancied combining apparently incompatible
ideas. According to Einstein's original GRT, acceleration and rotation
are RELATIVE - but that didn't really work.
Probably because they aren't.

Thus, for the explanation of the physical cause of inertia and its
manifestations such as the "absolute" speed of rotation, the choice
appears to be between:
- Physical Space (local, Newton)
- Physical effects from The Stars (action-at-a-distance by means of X,
Mach);
or, as you seem to assert here above,
- Unphysical influence by the human mind.

I did not claim any such thing. I said nothing about the physical cause
of inertia (which is really metaphysics anyway)

This IS about metaphysics. Newton and Mach admitted to the need of a
metaphysical postulate on which to base mechanics on; Mach's disagreement
concerned the particular model, not the requirement for one. Einstein didn't
use such a model as postulate; nevertheless he could not escape their
logical arguments about physical interpretation of the laws of physics.

Regards,
Harald


.

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