Re: Physical interpretation in physics.

"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.
Again .. you just don't get it ..
It looks like a speach confusion. ;-)

I'm not confused .. but I'm sorry to see that you are.

Laws of physics have to be consistent. that nonsense can also be
consistent does not mena the laws of physis is nonsense, or that
consitency is not required for laws of physcis.

Agreed. And as I repeatedly stressed, that's not the issue for the
physical interpretation of physics.
Perhaps logic isn't your forte
It looks more like it ain't yours ;-)

Quite to the contrary. Please .. look up the difference between necessary
and sufficient, before you embarrass yourself further.

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
No .. the ship is just a ship. We can associate the concept of a frame
of reference with it :)
A frame is commonly a thing - check the dictionary :-)

Not in physics. Maybe you should try studying it to find out?

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.
I'm not .. you're the one insisting that frames of reference are
physical. They aren't .. they can simply be associated with, and
described by, something physical

Instead you misread what I wrote and next argued against your own straw
man.

I constructed no strawman .. and did not argue against myself

Let it be. :-)

Good advice

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.
So you get different physics in a non-inertial frame of refernece.. No
one is disagreeing with that.
No one suggested that anyone is disagreeing with that. :-)

A lot of poeple seem very confused by the idea of inertial frames .. Sue for
one. Sh'e argue against anything, usually out of ignorance.

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. :-)
You gave a lecture .. where?
Here above. ;-)

Nope .. don't see any.

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.
What co-rotating frame?
The one in which the object is in rest.

I know what it is .. just wondering where that suddenly appeared from .. we
weren't discussing co-rotating frames and suddenly they appeared in your
post from nowhere

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.
I wasn't discussing Newton and Mach
Then you are in the wrong thread!
You responded to my reaction to:
"Newton, which viewed space as purely passive & not contributing to the
process"

No .. I didn't. I don't know what you think I posted, but it wasn't a
response to that

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.
Fine .. nothing wrong with metaphysics, or physics .. as long as one
knows what one is referring to.

Right.

It appears all this has drifted so far off topic, I don't know what was
being talked about .. oh that's right .. whether rotation was absolute ..

In fact, it was about the claim that "Newton viewed space as purely
passive & not contributing to the process".
And we were agreeing that rotation is absolute.

Yes .. it is. That's what I said as well. Why are you arguing with it?

as we have the concept of an inertial frame of reference (and whatever
physical things it may correspond to),

The "whatever" was Newton's argument. :-)

and because rotation is acceleration (non-inertial), it is absolute wrt
the inertial frames of reference in which our laws of physics are framed.
At least in terms of SR. Things are less clear when we bring GR into
play :)

That depends on one's version of GRT. :-)
I'm out of here. Enjoy your weekend!

You too.


.

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