Shocker: Nothing Moves in Spacetime!!!
SavainL
deterministic reality. Be prepared also to believe that absolutely
nothing can move in spacetime. If this comes as a shock to you, read on.
While exchanging ideas with other posters here on sci.physics, I was
astonished to discover that many students of relativity assumed that
spacetime was this extremely rigid yet curvable geometric structure. We
are indeed taught that matter curves spacetime which in turn affects the
motion of matter. It does seem to make sense. Kinda. Most people have
no understanding of general relativity. Even physicists will admit to not
having a proper understanding of it and those who claim to understand it
cannot explain it to those who don't. Strange...
It turns out that there's a little known aspect of spacetime (the
backbone of general relativity) that is almost never taught to students of
physics. It is so disturbing and revealing that general relativists are
seldom willing to discuss it. I first heard about it a little over a year
ago from a physics professor with whom I had corresponded in the past. He
sort of mentioned it nonchalantly, and I made nothing of it at the time.
I simply put it in a back corner of my mind for later retrieval. Recently
I had the opportunity to bring it out to the forefront of my consciousness
and the "fit hit the shan", so to speak. Here it is:
NOTHING MOVES IN SPACETIME!!!
The spacetime concept was created because physicists believed that time
could be viewed as one of the 4 dimensions of reality. The problem with
making time a dimension is that it renders spacetime completely
motionless. I mean dead, changeless, unchangeable. Spacetime is a 100%
deterministic structure in which nothing can change from the infinite past
to the infinite future!!! Why? Because, if you try to change anything in
spacetime you end up with a circularity. Change requires time. But time
is already part of the structure!!! It's like saying time changes over
time. See the problem? It is completely intractable. Yet countless
physicists are willing to live with it as if the problem weren't there.
Albert Einstein taught us that the motion of matter is governed by the
geometry of spacetime. We are told that spacetime is extremely rigid: it
is mostly flat except in the vicinity of massive bodies. Matter has the
ability to curve spacetime around it, a phenomenon which results,
according to general relativists, in what we commonly experience as
gravity. But how can matter curve spacetime if spacetime cannot change?
Well, you might say, maybe spacetime is already pre-curved in the
infinite future. This introduces a new dilemma which flies in the face of
the logic of cause and effect. One of the things we know about cause and
effect is that a cause must precede its effect. So if spacetime is
precurved, how can this curvature be caused by massive bodies? I
understand that this may be a little hard to think about (I had a hard
time seeing the problem at first) but almost anyone should be able to
figure out. It's not really all that hard.
This is one of the most damaging pieces of information I know of that
one can use against the idea of spacetime. Spacetime requires a 100%
deterministic reality from the eternal past to the eternal future. What
does that tell you about Einstein's adamant stance against quantum
physicists' assertion that nature is governed partially by chance? This
gives new meaning to the often quoted "God does not play dice with the
universe". Heck, it wouldn't matter whether God played dice or not. The
outcome is already determined zillions of years in advance! Does anyone
want to live in Einstein's spacetime driven reality? I don't. It's a
depressing reality, to say the least. Spacetime is so much bunk!
Best regards,
Louis Savain
--
I reserve the right to change my opinion in the face of strong evidence to
the contrary. By all means, do contradict me.
Matthew J. McIrvin
> This is one of the most damaging pieces of information I know of that
> one can use against the idea of spacetime. Spacetime requires a 100%
> deterministic reality from the eternal past to the eternal future. What
> does that tell you about Einstein's adamant stance against quantum
> physicists' assertion that nature is governed partially by chance? This
> gives new meaning to the often quoted "God does not play dice with the
> universe". Heck, it wouldn't matter whether God played dice or not. The
> outcome is already determined zillions of years in advance! Does anyone
> want to live in Einstein's spacetime driven reality? I don't. It's a
> depressing reality, to say the least. Spacetime is so much bunk!
Yes, it's true-- the curvature of general-relativistic spacetime can only
be coupled to matter if that matter, itself, moves in a completely
deterministic manner. And this is a big hole in general relativity.
If *that* is your objection to general relativity, then why do you
consider John Baez an adversary? This is precisely why *he* doesn't
believe in general relativity, and he's said so many times (read the
"quantum bowling ball" thread for a recent example of this). Why do you
think he's working on quantum gravity, otherwise?
No physicist in the world-- at least no physicist I know of-- considers
general relativity anything more than a classical (that is, non-quantum)
approximation to the true dynamics of gravitation. And spacetime probably
*isn't* anything like the smooth manifold described by GR, on a
fundamental level.
--
Matt McIrvin http://world.std.com/~mmcirvin/
--
Nntp-Posting-Host: world.std.com
Path: mmcirvin
Date: Sat, 30 Mar 1996 02:41:04 -0500
From: mmci...@world.std.com (Matt McIrvin)
LBsys
mmci...@world.std.com (Matthew J. McIrvin) schreibt:
>Yes, it's true-- the curvature of general-relativistic spacetime can only
>be coupled to matter if that matter, itself, moves in a completely
>deterministic manner. And this is a big hole in general relativity.
Could that 'hole' be explained to a layman in simple words, or say a nice
picture? Is there a gap between the certainty of big number trials (i.e.
determinism) and the uncertainty of the single event?
Lorenz Borsche (FRG)
Dubium sapientiae initium. [Descartes]
Vanesch P.
: Im Artikel <mmcirvin-190...@news.std.com>,
: mmci...@world.std.com (Matthew J. McIrvin) schreibt:
: >Yes, it's true-- the curvature of general-relativistic spacetime can only
: >be coupled to matter if that matter, itself, moves in a completely
: >deterministic manner. And this is a big hole in general relativity.
: Could that 'hole' be explained to a layman in simple words, or say a nice
: picture? Is there a gap between the certainty of big number trials (i.e.
: determinism) and the uncertainty of the single event?
I'll give this one a try. General Relativity is no exception to other "classical"
theories, so it is not necessary to delve into the issues of warped spacetime
to understand it.
A classical theory (be it newtonian mechanics, fluid dynamics, continuum mechanics,
electromagnetism etc...) gives you usually a theoretical frame and some "input/output"
handles towards matter. I will try to make clear what I mean:
Take electromagnetism. You have the theoretical frame, with the E and B fields,
the Maxwell equations and the Lorenz (-: force. So you would think you have it
all. WRONG ! In the maxwell eqs, there are 2 terms, the charge density and the
current density, which are EXTERNAL. Consider them the INPUT of the theory.
It is determined by the motion of matter. On the other hand there is the Lorentz
force: it couples to matter, and can be considered as the OUTPUT of the theory.
In order to get a closed mathematical problem (meaning you can call your maths
collegue and ask him to solve it) you need to attribute something extra. It is
how matter decides to take the output of the theory and respond to it in respect.
In our case, the Lorentz force is taken to influence matter, and a certain
prescription (called a BEHAVIOURAL EQUATION) that describes the, eh, behaviour
of matter is used to tell you what will be the resulting charge and current densities.
(which are then the input of the theory again, and the circle is closed).
This behavioural stuff can be several things: it can be simply Newton's equation
F = m.a if we are only considering one, free, charged particle. Even there, there
is an extra input: the mass of the particle. But in macroscopic systems, the
behavioural equation can be given by Ohm's law, or a more complicated variation of it,
or something else (like a behavioural eq. for a plasma).
Other example: continuum mechanics. There are 2 fields of importance there:
the field of the displacements of the infinitesimal matter elements, and the field
of the tensions in matter. One set of relations is given from first principles
by applying Newton's law to the infinitesimal matter elements. But again, this
is not a closed system of equations.
Another set of (again, behavioural equations) is needed to describe the response
of matter (in the form of displacements) when subject to certain tensions.
Here it is a bit harder to separate "input" from "output".
All these behavioural equations are or completely empirical (such as Ohm's law),
or they are the result of a theory of matter, but they are not part of the
classical theory under consideration. And except for plasma physics, these
"theories of matter" need a quantum description of some kind.
As my professor of materials science used to say: "Without behavioural equations
and the empirism that goes with it, it wouldn't matter if we would build a bridge
out of steel or out of butter."
Back to GR (which is also a classical theory).
There are 2 elements at play: the Einstein tensor (which is just a very
complicated way of coding the metric of spacetime) and the stress-energy
tensor. The "first principles" part of GR is the equality of both, which
is just Einstein's equation.
It tells you that IF YOU KNOW the "stress-energy" of matter, eg, how matter
is moving, then you know the Einstein tensor (and hence, the metric, and
hence how spacetime is curved).
But how do you get the stress-energy tensor ?
Well, that is, again, THE BEHAVIOURAL PART of our classical theory and
is not given by GR itself (just as the elasticity of butter or steel isn't
given by continuum mechanics, but by an empirical equation).
It has to give you the opposite relationship: given a certain metric,
what is the stress-energy tensor.
It will depend on how matter will behave under influence of gravity. If there
would be no other interaction in the universe, then every particle would follow
a geodesic, and the stress-energy tensor would be easily derivable from
this knowledge (and the kind of particle). But if there are many things going
on, like nuclear interactions, electromagnetic interactions etc... things
get more complicated.
This is not a particular problem of GR. It is the problem of every "partial"
theory in general, and every classical theory especially.
cheers,
Patrick.
Who is trying out his newsserver in Brussels, cuz the one in DESY has given
up apparently.
me...@cars3.uchicago.edu
>Im Artikel <mmcirvin-190...@news.std.com>,
>mmci...@world.std.com (Matthew J. McIrvin) schreibt:
>
>>Yes, it's true-- the curvature of general-relativistic spacetime can only
>>be coupled to matter if that matter, itself, moves in a completely
>>deterministic manner. And this is a big hole in general relativity.
>
>Could that 'hole' be explained to a layman in simple words, or say a nice
>picture? Is there a gap between the certainty of big number trials (i.e.
>determinism) and the uncertainty of the single event?
>
in classical physics too. True, it is not curved and the time and
space parts are decoupled (meaning that no transformation mixes time
and space). Nevertheless it is there and classical machanics works
very well, quite oblivious to quantum effects till you get to very
small scales. So fine, we know by know that classical mechanics is
just an approximation, not the real thing. But within a broad realm
it is an excellent approximation.
The proper analogy here is optics. We've geometrical optics where we
talk about "rays" and which is indistinguishable from particle
dynamics and we've wave optics which takes into account the fact that
light is a wave. Now, in principle ray optics is "wrong". However it
works extremely well till you start considering features of dimensions
comparable to wavelength. The shorter the wavelength the farther you
can go before wave effects become noticable. And the wavelengths
associated with QM are very short indeed.
So I would rephrase Matthew's statement above as follows:
___________
A theory in which the curvature of spacetime is fully coupled to
matter can be exact only if this matter moves in a completely
deterministic manner. Else it is to be considered an approximation
which may, at some point, be replaced by a more exact theory.
__________
So, IMO there is no "big hole" unless somebody expects physical
theories to be perfect (I don't). What's there is an indication that
the two most successful theories we've nowadays, QM and GR, are in
some respects incompatible and either one or both will have to be
modified before they can be smoothly combined.
Mati Meron | "When you argue with a fool,
me...@cars.uchicago.edu | chances are he is doing just the same"
john baez
>No physicist in the world-- at least no physicist I know of-- considers
>general relativity anything more than a classical (that is, non-quantum)
>approximation to the true dynamics of gravitation. And spacetime probably
>*isn't* anything like the smooth manifold described by GR, on a
>fundamental level.
Exactly. The main reason I am interested in quantum gravity is that it
is bound to completely shatter the picture of spacetime given to us by
previous theories: Aristotelian and Newtonian physics, special and
general relativity. But of course one needs to understand general
relativity, even though it's not "the ultimate truth", if one is going
to have any chance to understand quantum gravity. So I spend a lot of
time trying to understand (and explain) general relativity, even though
it's false!
In fact, for all the theories of physics we have, we either know they
are false, because they are incomplete (general relativity and the
Standard Model), or we don't know they are true, because they make no
new experimentally verified predictions (e.g. string theory).
Nonetheless some of these theories are incredibly successful, so one
must learn them to make any progress.
me...@cars3.uchicago.edu
"incomplete" or "inexact" instead of "false", and that's for two
reasons. First, with all the laymen around going out of their way to
misinterpret and misquote all they hear, I would hate the idea to keep
explaining why do we use false theories. Second, the usage of "false"
implies indirectly that somewhere out there there is a "true" theory,
while in fact the most we can hope for is a theory which is "not known
to be incomplete"
LBsys
: mmci...@world.std.com (Matthew J. McIrvin) schreibt:
: >Yes, it's true-- the curvature of general-relativistic spacetime can
only
: >be coupled to matter if that matter, itself, moves in a completely
: >deterministic manner. And this is a big hole in general relativity.
: Could that 'hole' be explained to a layman in simple words?
Patrick and Mati answered as follows:
pvan...@vub.ac.be (Vanesch P.) schreibt:
>It will depend on how matter will behave under influence of gravity. If
>there would be no other interaction in the universe, then every particle
>would follow a geodesic, and the stress-energy tensor would be easily
>derivable from this knowledge (and the kind of particle). But if there
are
>many things going on, like nuclear interactions, electromagnetic
>interactions etc... things get more complicated.
>
>This is not a particular problem of GR. It is the problem of every
"partial"
>theory in general, and every classical theory especially.
me...@cars3.uchicago.edu schreibt:
__________
>A theory in which the curvature of spacetime is fully coupled to
>matter can be exact only if this matter moves in a completely
>deterministic manner. Else it is to be considered an approximation
>which may, at some point, be replaced by a more exact theory.
__________
>So, IMO there is no "big hole" unless somebody expects physical
>theories to be perfect (I don't). What's there is an indication that
>the two most successful theories we've nowadays, QM and GR, are in
>some respects incompatible and either one or both will have to be
>modified before they can be smoothly combined.
Thanks, Patrick and Mati, it's good to know, that the GR/QT community
agrees even upon uncertainties and contradictions of their shared
theories.
What does a layman make out of your words? When you're talking of matter,
you obviously seem to have both in mind at the same time: the single
particle, whichs behaviour is described by QT as well as for example JB's
brick tumbling through space (BTW: where's the triple point for bricks
:-?), thus bodies.
In 'classic' systems, that's what I get from both of you, we have
determinism, so as GR tells how gravity (of matter) is bending space-time,
thus space-time is forming gravity, which in reverse... and so forth,
which means: we very well know, where good old earth will be in about 1000
years. At least that's how it seems.
Now QT can't even tell us, where a single particle will be next (here,
there, everywhere). We might get a probability, and that's about it. Oh,
it cannot even tell us, if its *matter* we are talking about, QT just
waves us a gentle 'hello' while passing :-).
Now as GR tells us exactly, how the future should look like, whereas QT
says "It might look like this, but don't ever think of getting closer to
it", physicist are confused. Is that so? Is that the problem? Is it, b/c
in QT there is no influence of gravity to be calculated - as no one knows
how? And as we can't measure it, so we have not even the faintes idea what
the mathematics could look like?
Now to enlighten me further:
Lurking at the GR tutorial I get the impression that it is far from being
easy looking only at a simple flat spacetime system. When someone tried to
add a solar system with just one sun and one planet, JB cried 'Fire!' as
the maths would really get complicated. Now regarding a whole lot off side
effects (more planets, moons, asteroid belts, comets in and out), I
'feel', your maths describing it would blow up to an extent that even
Crays won't handle, not to speak of the influence of interstellar matter,
our own or other galaxies. We may end up with Laplaces demon of another
sort: Although the axioma are simple, the model describing reality would
be far to complex, then to ever being resolved, and one could even say, it
cannot be resolved, so the future again is open. Not in every direction,
but this is not at all what QT says: Behind the slit, I cannot tell where
the photon will go this time, but it follows a certain pattern. As the way
backwards is not included, I might very well say: I don't know where it's
going for certain, but certainly not back at me.
Now for QT: Yes, we can't tell about the single event, but we can tell
about lot's of events. With a few hundred particles, our incertainty is
gone and made room for statistical probability. It's like tossing a coin:
although you just cannot predict the single throw, you can predict 0.5
times heads, when throwing 1 million times and summing it up to one. So QT
is uncertain for the single throw, but very precise for big numbers. As GR
is very certain for simple flat or two body systems (each body containg
big numbers of particles) but looses precisesness the more bodies are in
the game. It's seems to represent both ends of the balance. It's looks
like a macro/micro problem. Regarding the universe the spin of an electron
is meaningless (Pauli forgive me), and regarding a photon, spacetime may
have an effect on the obserever, watching his clock, but thats highly
theoretical. A pion doesn't care for the deterministic predictions of GR -
it decays, when it's probable time is up. I wouldn't try to repair an
ocean liner with a screw driver made for my wrist watch. I wouldn't try to
repair my wrist watch with a screw made for an ocean liner. Describing the
universe with QT is as useless as applying the laws of gravity on a single
particle. That's all I can see there is.
This sounds to be far to easy. Obviously I haven't been able to catch the
real twist. So I have to ask you to try to enlighten me further. Will you?
Thanks in advance.
LBsys
schreibt:
>Exactly. The main reason I am interested in quantum gravity is that it
>is bound to completely shatter the picture of spacetime given to us by
>previous theories: Aristotelian and Newtonian physics, special and
>general relativity. But of course one needs to understand general
>relativity, even though it's not "the ultimate truth", if one is going
>to have any chance to understand quantum gravity. So I spend a lot of
>time trying to understand (and explain) general relativity, even though
>it's false!
Ok, I'll buy that and don't misinterprete false as being false - just
incomplete (as Mati has correctly laid out)!
Newtons mechanics wrt the above interpretation were just incomplete,
right? It was sort of a special case of GR. GR had to add a factor for
high (relative) velocities - which made the old formula less elegant. But
anyway cancels out in certain (Newtonian) cases.
Now shouldn't we look forward to a quantum gravity theory, which includes
GR as 'a special case' ?
Instead of something that "is bound to completely shatter the picture of
spacetime given to us by previous theories"
(... I always had a great like and infallible feeling for special cases in
school maths: often found a simple solution instead of the general one,
b/c the teacher once again had choosen a neatly formed cube or a
rectangular triangle or the like - drove them mad :-).
I would suspect the quantum gravity to evolve as a rather minor
'correction factor' in reality. Don't get me wrong: All I'm saying is that
counted out on a big scale, we might still use GR formulas like we do now
use Newtonion eqns, when we expect GR effects to be neglectable. Or am I
thinking complete in the wrong direction?
me...@cars3.uchicago.edu
>Im Artikel <4l8ud9$9...@guitar.ucr.edu>, ba...@guitar.ucr.edu (john baez)
>schreibt:
>
>>Exactly. The main reason I am interested in quantum gravity is that it
>>is bound to completely shatter the picture of spacetime given to us by
>>previous theories: Aristotelian and Newtonian physics, special and
>>general relativity. But of course one needs to understand general
>>relativity, even though it's not "the ultimate truth", if one is going
>>to have any chance to understand quantum gravity. So I spend a lot of
>>time trying to understand (and explain) general relativity, even though
>>it's false!
>
>Ok, I'll buy that and don't misinterprete false as being false - just
>incomplete (as Mati has correctly laid out)!
>Newtons mechanics wrt the above interpretation were just incomplete,
>right? It was sort of a special case of GR. GR had to add a factor for
>high (relative) velocities - which made the old formula less elegant. But
>anyway cancels out in certain (Newtonian) cases.
>Now shouldn't we look forward to a quantum gravity theory, which includes
>GR as 'a special case' ?
>Instead of something that "is bound to completely shatter the picture of
>spacetime given to us by previous theories"
>
presented as "completely shattering the previous picture" but when the
dust clears it'll turn out that it is just a more general thing, the
previous theories being special cases of. As it should be since
obviously it must asymptotically reduce to the previous theories in
the reange of parameters within which they work.
>
>I would suspect the quantum gravity to evolve as a rather minor
>'correction factor' in reality. Don't get me wrong: All I'm saying is that
>counted out on a big scale, we might still use GR formulas like we do now
>use Newtonion eqns, when we expect GR effects to be neglectable. Or am I
>thinking complete in the wrong direction?
No, I think that's the right direction. If quntum gravity would make a
big difference, "in reality", we would observe by now some
discrepancies between the predictions of QM or GR (or both) and
reality.
gl...@gnn.com
In article <4l8ud9$9...@guitar.ucr.edu> john baez wrote:
>>No physicist in the world-- at least no physicist I know of--
>>considers general relativity anything more than a classical (that
> Exactly. The main reason I am interested in quantum gravity is
>that it is bound to completely shatter the picture of spacetime
>given to us by previous theories: Aristotelian and Newtonian
>physics, special and general relativity. But of course one needs
>to understand general relativity, even though it's not "the
>ultimate truth", if one is going to have any chance to understand
>quantum gravity. So I spend a lot of time trying to understand
Why do you want to understand, much less "expain", a false
theory. BTW, thanks for announcing your admittedly expert opinion
that "it's false". Good for you!
Glird http://members.gnn.com/glird/reality.htm
SavainL
>In article <4l8ud9$9...@guitar.ucr.edu>, ba...@guitar.ucr.edu (john baez)
>writes:
>>In article <mmcirvin-190...@news.std.com>
>>mci...@world.std.com (Matthew J. McIrvin) writes:
>>
>>Exactly. The main reason I am interested in quantum gravity is that
>>it is bound to completely shatter the picture of spacetime given to us
>>by previous theories: Aristotelian and Newtonian physics, special and
>>general relativity. But of course one needs to understand general
>>relativity, even though it's not "the ultimate truth", if one is going
>>to have any chance to understand quantum gravity.
Balderdash! No one needs to wait for quantum gravity to completely
shatter the picture of spacetime. It is shattered now! It has miserably
collapsed under the weight of its own stupidity. And BTW, there's no need
to bring yet another convoluted theory into physics. There's only one
way in which all forces are mediated, including the gravitational force,
and that is through the exchange of particles, i.e., through particle
interactions. What's wrong with using a proven concept?
>> So I spend a lot of
>>time trying to understand (and explain) general relativity, even
>>though it's false!
>>
>>In fact, for all the theories of physics we have, we either know they
>>are false, because they are incomplete (general relativity and the
>>Standard Model), or we don't know they are true, because they make no
>>new experimentally verified predictions (e.g. string theory).
>>Nonetheless some of these theories are incredibly successful, so one
>>must learn them to make any progress.
>>
>I don't like to nitpick but I would seriously suggest using the term
>"incomplete" or "inexact" instead of "false", and that's for two
>reasons. First, with all the laymen around going out of their way to
>misinterpret and misquote all they hear, I would hate the idea to keep
>explaining why do we use false theories.
This is incredible. I grant you that I would not go as far as saying
that GR is false due to it being based on spacetime, for the same reason
that I would not as far as to say that Newtonian physics is false because
it postulates action at a distance. But at least Newton did not come out
and say that there is in fact action at a distance, only that massive
bodies behave *as if* there were action at a distance. Newton is to be
commended for his caution. Spacetime, on the other hand, is *openly*
given and taught all over the world as *the* cause of motion and gravity.
The truth is that the idea of spacetime curvature on which GR is very
much based is indeed 100% false. Saying that it is "incomplete" is like
saying that the flat earth theory is not false but merely "incomplete".
What nonsense! Spacetime is stupidity at its worst! Why? Because it did
not come from a bunch of pseudo-scientists and amateur physicists; it
came from the creme de la creme, the Nobel prize winners of physics. For
you guys to try to rationalize an obvious nonsense by using ambiguous
language like "incomplete" does not strike me as particularly courageous.
Baez is right on in this respect. Spacetime *is* false.
Why do physicists continue to perpetuate such a stupid concept by
claiming it's incomplete? Have some strength and go to your students and
tell them the truth: "Hey guys and gals, you know this spacetime thing
we've been telling you about all these years, yeah, this awesomely
beautiful thing that is responsible for gravity, black holes time travel
and all that good stuff, well it's completely bunk! Surpraaaise!" Now,
that would be true courage. Guess what! I'm not holding my breath
waiting for that to happen!
> Second, the usage of "false"
>implies indirectly that somewhere out there there is a "true" theory,
>while in fact the most we can hope for is a theory which is "not known
>to be incomplete"
No amount of rationalizing is going to dig spacetime physicists out this
absurd hole they got themselves into. We don't judge theories by
comparing them to "true" theories. We judge them by comparing them with
reality. In this regard, spacetime is one of the most unrealistic
theories of them all because it has no basis in reality. It was wrong
right out of the box! Heck, I'd say the flat earth concept has more merit
than spacetime as we don't expect any better coming from non-scientists.
Why have physicists been sitting on this nonsense for so long? Why have
they not informed their students that there's a major logical flaw in the
idea of spacetime that renders it completely useless as a basis for
reality? Why is it taking an outsider to bring this monumental flaw into
the open? What are you afraid of? And don't tell me you've been saying
the same thing that I'm saying all along because you haven't. No one's
going to believe it. Gosh! When I think that a whole generation of young
people have been brainwashed into believing in this spacetime manifold
absurdity! What a waste!
LBsys
(I post it with his consent and b/c it really gave me hints, what the
whole debate is about and why JB is so important, maybe other laymen get
enlightened too. Further enlightments can be found in the thread "When GR
weds QM, what are likely offspring"?):
> Thanks, Patrick and Mati, it's good to know, that the GR/QT community
agrees
> even upon uncertainties and contradictions of their shared theories.
Eh, ahum. Yes, of course we know that physics isn't finished yet !
It is one of the big open questions: how to "quantize" GR. John
Baez is one of the "happy few" working on that problem. He hasn't
found it yet. It is called "job protection" :-)
>
> What does a layman make out of your words? When you're talking of
matter, you
> obviously seems to to have both in mind at the same time: the single
> particle, which's behaviour is described by QT as well as for example
JB's
> brick tumbling through space (BTW: where's the triple point for bricks
:-?),
> thus bodies.
>
> In 'classic' systems, that's what I get from both of you, we have
> determinism, so as GR tells how matter is bending space-time, thus
space-time
> is forming matter, which in reverse... and so forth, which means: we
very
> well know, where good old earth will be in about 1000 years. At least
that's
> how it seems.
in principle. Whether we can actually do the calculation is another
story.
> Now QT can't even tell us, where a single particle will be next (here,
there,
> everywhere). We might get a probability, and that's about it. Oh, it
cannot
> even tell us, if its *matter* we are talking about, QT just waves us a
gentle
> 'hello' while passing :-).
Yes. And people tried almost everything to avoid coming to that
conclusion. But apparently there is no escape :)
> Now as GR tells us exactly, how the future should look like, whereas QT
says
> "It might look like this, but don't ever think of getting closer to it",
> physicist are confused. Is that so? Is that the problem?
More or less. GR is still a "classical theory", like Newtonian
mechanics is, and like Maxwellian electromagnetism is. Now, QT
gives us a rule how to make a quantum theory out of a classical
theory. It works for electromagnetism ==> QED, and it works for
newtonian mechanics ==> non-relativistic quantum mechanics, which
is used all over in chemistry, lasers, solid state physics, transistors
etc...
But it doesn't work for GR. GR doesn't have the right structure
to apply the "make it quantum" rule of Quantum Theory.
So that's a big puzzle.
> Is it, b/c in QT
> there is no influence of gravity to be calculated - as no one knows how?
And
> as we can't measure it, so we have not even the faintes idea what the
> mathematics could look like?
The fact that we don't measure quantum gravity effects because they're
way too weak is also a problem: we have no clue !
> Now to enlighten me further:
> Following the GR tutorial I get the impression that it is far from being
easy
> looking at a simple flat spacetime system. When someone tried to add a
solar
> system with just one sun and one planet, JB cried 'Fire!' as the maths
would
> really get complicated. Now regarding a whole lot off side effects (more
> planets, moons, asteroid belts, comets in and out), I 'feel', your maths
> describing it would blow up to an extent that even Crays won't handle,
not to
> speak of the influence of interstellar matter, our own or other
galaxies. We
> may end up with Laplaces demon of another sort: Although the axioma are
> simple, the model describing reality is far to complex, then to ever
being
> solved, and one could even say, it cannot be solved, so the future again
is
> open.
Yes, complexity is still with us. We may have the equations, but don't
know how to find the solutions. The last bit is conveniently called
a mathematical problem but it is there nevertheless.
Even more. The stuff I'm working on (but as - unfortunately - an
experimentalist), is Quantum Chromodynamics. There, we have the
theory, the equations, and we don't even know how to solve a
SIMPLE problem. (well, we know some aspects, but we don't know
any exact solution, and we don't even know if our approximations
are approximations !)
> Not in every direction, but this is not at all what QT says: Behind the
> slit, I cannot tell where the photon will go this time, but it follows a
> certain pattern. As the way backwards is not included, I might very well
say:
> I don't know where it's going for certain, but certainly not back at me.
Ok, but for that you don't need a lot of theory :)
> Now for QT: Yes, we can't tell about the single event, but we can tell
about
> lot's of events. With a few hundred particles, our incertainty is gone
and
> made room for statistical probability. It's like tossing a coin:
although you
> just cannot predict the single throw, you can predict 0.5 times heads,
when
> throwing 1 million times and summing it up to one. So QT is uncertain
for the
> single throw, but very precise for big numbers. As GR is very certain
for
> simple flat or two body systems (each body containg big numbers of
particles)
> but looses precisesness the more bodies are in the game. It's seems to
> represent both ends of the balance.
Yes, that is the nice thing. All this "incompleteness of GR / QT" stuff
is only a matter of principle. There were QT matters, GR doesn't play
a role at all and vice versa. It is only in EXTREMELY strange and weird
places (like the first billionth of second of the big bang - or tiny
black holes) that both of them play a role. These weird places are
"at the Planck scale".
If you're a practical guy, you say: GREAT ! So we actually know
everything (in principle) except for these weird places we'll never
study anyhow.
If you are a philosopher, you say SHIT ! We have a principal
inconsistency between GR and QT, and no experiment in the coming
500 years (rough guess :) is going to address these matters, so
we will not know.
And if you're a crackpot, you silently solve the problem and you
tell the world that TIME IS BOILING EGG :-)
It's looks like a macro/micro problem.
> Regarding the universe the spin of an electron is meaningless (Pauli
forgive
> me), and regarding a photon, spacetime may have an effect on the
obserever,
> watching his clock, but thats highly theoretical. A pion doesn't care
for the
> deterministic predictions of GR - it decays, when it's probable time is
up. I
> wouldn't try to repair an ocean liner with a screw driver made for my
wrist
> watch. I wouldn't try to repair my wrist watch with a screw made for an
ocean
> liner. Describing the universe with QT is as useless as applying the
laws of
> gravity on a single particle. That's all I can see there is.
That is the "practical guy viewpoint". The rest is indeed just a matter
of taste. I more or less adopt the same philosophy, because it must be
way frustrating to FINALLY UNIFY GR AND QT, and none of your new
predictions will be verified in the coming 500 years (if ever). We
actually have (a few thousand) candidate unifications: that's what
string theory is all about. But the people who work on that NOW will
never see it confirmed or rejected. Must be a pretty hard thing to
swallow I guess....
Of course, when I say this to a string theorist, he quite rightly
corrects me: How can you know ? Right, it MIGHT be that some very
accessible effect is predicted only by string theory. But I don't
think so !
> Obviously I haven't been able to catch the real twist. So I have to ask
you
> to try to enlighten me further. Will you? Thanks in advance.
>
On the contrary, I think you have a rather good view on it.
cheers,
Patrick.
PS: I won't post this again, I just mailed it to you. You can post it
if you want to, but here, both of my newsservers are utterly confused
(the one in Brussels and the one in DESY).
SavainL
In article <4lbi44$q...@news-e2c.gnn.com>, gl...@gnn.com () writes:
>In article <4l8ud9$9...@guitar.ucr.edu> john baez wrote:
>>>No physicist in the world-- at least no physicist I know of--
>>>considers general relativity anything more than a classical (that
>>>is, non-quantum) approximation ...
>> Exactly. The main reason I am interested in quantum gravity is
>>that it is bound to completely shatter the picture of spacetime
>>given to us by previous theories: Aristotelian and Newtonian
>>physics, special and general relativity. But of course one needs
>>to understand general relativity, even though it's not "the
>>ultimate truth", if one is going to have any chance to understand
>>quantum gravity. So I spend a lot of time trying to understand
>>(and explain) general relativity, even though I know it's false.
> Why do you want to understand, much less "expain", a false
>theory. BTW, thanks for announcing your admittedly expert opinion
>that "it's false". Good for you!
John Baez is a strange guy. I feel like I'm riding a roller-coaster
whenever I read Baez's messages. He goes from talking from both sides of
his mouth to showing amazing courage and wit. I realize I'm not in his
shoes and I don't envy his position. But I do commend him for his courage
in this case.
Jim Conner
> Why do you want to understand, much less "expain", a false
> theory. BTW, thanks for announcing your admittedly expert opinion
> that "it's false". Good for you!
Sheesh. Get a grip, buddy. Do you think that *any* theory provides a
perfect description of Nature over all ranges of energy, all time scales,
etc.? The best that we can hope for is continually improving
approximations to what Nature is really doing. Some of these
approximations are very good, but you can bet that someday someone will
make a measurement or perform an experiment that shows one (or more) of
these approximations to be inadequate.
*All* of our theories are false, in the sense that they do not perfectly
describe the workings of the world in all conditions. This does not take
away from their usefulness over limited ranges, or make it any less proper
to teach and explain them to others.
Jim Conner
jc...@cornell.edu
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john baez
>Im Artikel <4l8ud9$9...@guitar.ucr.edu>, ba...@guitar.ucr.edu (john baez)
>schreibt:
>Now shouldn't we look forward to a quantum gravity theory, which includes
>GR as 'a special case' ?
>Instead of something that "is bound to completely shatter the picture of
>spacetime given to us by previous theories"
Of course quantum gravity should reduce to general relativity in most
circumstances, and in many circumstances provide only miniscule
correction terms. General relativity will remain incredibly useful for
many problems. But nonetheless, quantum gravity is bound to completely
shatter the picture of spacetime --- the worldview --- given to us by
previous theories.
It's just like what general relativity did to Newtonian gravity. In our
solar system, the general-relativistic corrections to Newtonian physics
are very small. Newtonian physics remains a extraordinarily useful
framework for dealing with many physics problems. It is also very
beautiful. So it will always be well worth mastering. But: even if
spacetime is only very SLIGHTLY curved, the fact that it's curved AT ALL
would completely blow the mind of anyone who grew up on the certainties
of Newtonian physics, one of which is Euclidean geometry.
It's almost as if someone said "Oh, by the way, 1 + 1 doesn't exactly
equal 2, but don't get upset: it's very, very close." Something
can be mindblowing, and conceptually very important, even if in most
practical situations its effects are very small. General relativity
radically altered our picture of what spacetime is like.
>I would suspect the quantum gravity to evolve as a rather minor
>'correction factor' in reality.
In most situations, probably. It might make a huge difference for what
happens at the singularity of a black hole, or at the very beginning of
the universe. Thus it might drastically change our theories as to the
origin and fate of the universe. There is a lot of work being done
along these lines already. But what matters to me, personally, most of
all, is how it will change our understanding of spacetime.
Tom Potter
> NOTHING MOVES IN SPACETIME!!!
> The spacetime concept was created because physicists believed that time
>could be viewed as one of the 4 dimensions of reality. The problem with
>making time a dimension is that it renders spacetime completely
>motionless. I mean dead, changeless, unchangeable.
In order to resolve an assertion,
one must establish a dichotomy,
which directly impacts the primary POINT of the assertion.
Savain made a specific assertion, which has NOT been addressed.
There has been a lot of hand waving, but no one has established a
dichotomy upon the SPECIFIC POINT of the assertion.
That is:
If "matter" exists at some x,y,z,t,
what does it change in reference to?
It seem to me that we are back to Zeno.
I assert that time-space and matter are just different expressions of
the same thing, and they all are just cycles and cycle ratios.
Kepler discovered that time-space and "matter" was the same thing
and expressed as: M(A) = distance(B)^3 / time^2
Einstein discovered that time and space was the same thing
and expressed as: x^2 + y^2 + z^2 = (ct)^2
But I think he should have expressed it as:
(x/c)^2 + (y/c)^2 + (z/c)^2 = t^2
which expresses space as time, which is closer to reality.
And, of course, I assert that time is simply a ratio of cycles:
time(X) = cycles(reference) / cycles(X)
Tom Potter http://pobox/~tdp
me...@cars3.uchicago.edu
>I asked:
Stuff snipped (reluctantly, but its getting long)...
I think that you got most, if not all, of the real twist. It is a
matter of looking at physics at two different levels. One is the
profound level of "understanding how the universe works" the other
isthe down to earth "OK, now given this situation, what's going to
happen". And both are important.
So we have various "incomplete" theories which work in a limited range
and work extremely good over there. They are here to stay. Engineers
didn't junk Newtonian mechanics and started using QM or relativity in
their calculations since, as you observe, the answers given by
Newtonian mechanics are perfectly good in their realm of operation and
the calculations are way simpler. Part of the art of applying science
to the real world is not to include everything but to include all
that's relevant.
At the same time we would like to join these "partial theories"
together. There is this human urge to understand what's going on and,
on the practical side, when you get a more general picture you may
ntice things that were overlooked before. So that's fine, but we
shouldn't think in terms of "we'll get an ultimate theory and apply it
to everything". I'm surethat even having a theory that combines all
of our knowledge, we'll then use it to derive simple approximations
valid for the various issues we care about and use these
approximations. Else, using your analogy, we'll end up with one
screwdriver which we try to use on everything and which is cumbersome
in all its applications.
SavainL
writes:
>In article <4lamn9$o...@newsbf02.news.aol.com>, lb...@aol.com (LBsys)
>writes:
>>[...]
>>Now shouldn't we look forward to a quantum gravity theory, which
>>includes GR as 'a special case' ?
>>Instead of something that "is bound to completely shatter the picture
>of spacetime given to us by previous theories"
>
>Judging by past experience we'll get something which will be first
>presented as "completely shattering the previous picture" but when the
>dust clears it'll turn out that it is just a more general thing, the
>previous theories being special cases of. As it should be since
>obviously it must asymptotically reduce to the previous theories in
>the reange of parameters within which they work.
It is true that a new theory of gravity would have to make predictions
that are least as good as GR or better. Saying that it would have to
"asymptotically reduce to" GR is misleading. Only the predictions need to
be as good or better than the old ones, not the theory. The new theory in
this case will completely replace the old one. It does not need to reduce
to GR since GR is based on the concept of spacetime, and spacetime, as we
should all know by now, is complete 100% nonsense!
Oz
Conner <jc...@cornell.edu> writes
>
>*All* of our theories are false, in the sense that they do not perfectly
>describe the workings of the world in all conditions. This does not take
>away from their usefulness over limited ranges,
As any artillery man or astronaut will readily confirm.
-------------------------------
'Oz "When I knew little, all was certain. The more I learnt,
the less sure I was. Is this the uncertainty principle?"
Keith Stein
writes
> GR is based on the concept of spacetime,
> and spacetime,
> as we
>should all
> know
> by now,
> is complete 100% nonsense!
>
>Best regards,
>
>Louis Savain
i don't understand.
Are you saying that
space is 100 % nonsense
and
time is 100 % nonsense ? ?
or
are you just saying
GR is 100 % nonsense ?
which is fine
if you just meant that!
--
Keith Stein
ale2
In article <4lbi44$q...@news-e2c.gnn.com>
gl...@gnn.com () writes:
>
stuff cut
> Why do you want to understand, much less "expain", a false
> theory. BTW, thanks for announcing your admittedly expert opinion
> that "it's false". Good for you!
the following has at best a monetary value of 0.02$ on a good day.
one reason i might want to understand GR
of all that we observe (science) we try to come up with theories which
make sense of what we observe. To me it seems GR does a pretty good job
of making sense of some of what we observe. To me then the structure of
GR (and most of conventional physics) gives a really strong clue to
some deeper model.
You don't have to marry her (GR), you could just be friends, get to
know her, who knows what could happen.
ale2
>
> So, IMO there is no "big hole" unless somebody expects physical
> theories to be perfect (I don't). What's there is an indication that
> the two most successful theories we've nowadays, QM and GR, are in
> some respects incompatible and either one or both will have to be
> modified before they can be smoothly combined.
the above grabbed me, if GR is really only an approximation as i take
from the above statement, can we also think of SR as also being only an
approximation and if so in what way?
thanks
john baez
>>In fact, for all the theories of physics we have, we either know they
>>are false, because they are incomplete (general relativity and the
>>Standard Model), or we don't know they are true, because they make no
>>new experimentally verified predictions (e.g. string theory).
>>Nonetheless some of these theories are incredibly successful, so one
>>must learn them to make any progress.
>I don't like to nitpick but I would seriously suggest using the term
>"incomplete" or "inexact" instead of "false", and that's for two
>reasons.
I sympathize with your suggestions, and normally follow them. I just
felt like being a bit provocative. But I don't think I was being
irresponsible, because I carefully explained what I meant.
>First, with all the laymen around going out of their way to
>misinterpret and misquote all they hear, I would hate the idea to keep
>explaining why do we use false theories.
It's not the layfolk who go out of their way to misinterpret things,
it's the fruitcakes. There is really nothing I can do to keep them from
making fools of themselves. These guys could look at a bus schedule
and come to the conclusion that it was the periodic table. So there is
no point in babying them.
I do think it's important not to confuse layfolk. But I don't think my
statement would confuse *them*. If it did, our little exchange here
should clear that up.
>Second, the usage of "false"
>implies indirectly that somewhere out there there is a "true" theory,
>while in fact the most we can hope for is a theory which is "not known
>to be incomplete"
Well, all I meant was that general relativity does not take quantum
mechanics into account, and the Standard Model does not take gravity
into account. This is worse than being "not known to be incomplete".
It's even worse than being "known to be incomplete". It is being
inconsistent with known facts. Nonetheless, these are the most accurate
theories we have! I'm not knocking them in the least. Anyone who wants
to understand physics thoroughly MUST learn these theories, because they
represent the current pinnacle of human accomplishment as far as physics
goes.
In a certain sense, everything we know about the fundamental laws of
physics has been built into these two theories. The fact that these
theories are not consistent with each other simply means we aren't done
understanding physics yet.
Keith Ramsay
In article <4lbii0$2...@newsbf02.news.aol.com>, sav...@aol.com (SavainL) wrote:
|For you guys to try to rationalize an obvious nonsense by using ambiguous
|language like "incomplete" does not strike me as particularly courageous.
I don't remember anybody claiming bravery here....
Spacetime is clearly not "obvious nonsense", so I think you must be
misunderstanding it in some basic way. Spacetime is the set of all
events, past, present and future. Not absurd at all.
I get the impression that you are somehow taking what somebody
has said about spacetime (i.e., talking about events) as
meaning some bizarre notion of future events being out there, already
"given", fated or already present or something. In fact it is just an
unfamiliar (to you) way of talking about events, including future
ones. For instance, the "set of cattle uncle Bob will own in 2025"
refers to things which don't yet exist, but it's perfectly reasonable
to talk about the collection anyway. It is just in the future. The
same holds for parts of spacetime in our future. The events have not
yet occurred, but in physics we may talk about them anyway.
|Baez is right on in this respect. Spacetime *is* false.
He said general relativity and the standard model are "false". I
don't recall him saying spacetime is false.
There are two types of objections here. One is the objection to
teaching hypothetical, theoretical ideas, which are bound someday
to be revised, as if they were simply true. On this we largely
agree. Certainly I agree that GR is bound to be revised as physics
progresses. This is what people are talking about when they say that
the theory is "incomplete". People are not rationalizing about this
here; we're acknowledging your point.
On the other hand, there is your claim that the theory was an awful
theory from the outset, obviously bad, because of some vague
apprehensions about space-time. People are *not* trying to
rationalize this point either, by saying GR is incomplete. It's
not relevant. If the idea were so bad, being incomplete wouldn't
make it any better. Nobody says it would.
We are simply telling you that this "problem" you think GR has,
that other theories do not have, is simply not a problem. You
think you've seen a problem, but you are simply confused. And
apparently somewhat overconfident of your understanding of the
matter. Do you really think the physics community is a bunch
of total idiots?
Keith Ramsay
SavainL
<sth...@sthbrum.demon.co.uk> writes:
>In article <4lcti8$f...@newsbf02.news.aol.com>, SavainL
><sav...@aol.com> writes
>
>> GR is based on the concept of spacetime,
>
>> and spacetime,
>
>> as we
>>should all
>
>> know
>
>> by now,
>
>> is complete 100% nonsense!
>>
>>Best regards,
>>
>>Louis Savain
>
>i don't understand.
>
>Are you saying that
>
> space is 100 % nonsense
In a deep Eleatic sense, it probably is. But in the context of this
discussion, I'll refrain from getting into this philosophical aspect of
it. BTW this was somewhat debated in another thread called "A Particle's
Position: Intrinsic or Extrinsic?"
> and
> time is 100 % nonsense ? ?
Time, viewed as a spatial dimension, is indeed 100% nonsense as I've
pointed out elsewhere. It is unfortunate that physicists and philosophers
have taken to dimensionalizing time.
> or
>
>are you just saying
>
> GR is 100 % nonsense ?
I don't know enough about GR to say one way or another. But since it's
based on spacetime curvature, it probably is 100% nonsense. It may have
been a case where the equations were fitted to observation. I don't know.
I do know from my understanding of calculus that it's relatively easy to
come up with equations that agree partially or wholly with reality. One
can then use these equations to make accurate predictions and then
incorrectly claim that one understands reality. Newton did it (come up
with great equations, that is) and yet it's clear that he had no idea what
was going on at the fundamental level.
>which is fine
> if you just meant that!
It woud bother me a little if it were just that. There's a lot more at
stake than just GR's nonsensical spacetime curvature.
gl...@gnn.com
In article <4le78n$b...@guitar.ucr.edu> john baez wrote:
>Well, all I meant was that general relativity does not take
>quantum mechanics into account, and the Standard Model does not
>take gravity into account. This is worse than being "not known to
>be incomplete". It's even worse than being "known to be
>incomplete". It is being inconsistent with known facts.
> Nonetheless, these are the most accurate theories we have! I'm
>not knocking them in the least.
>Anyone who wants to understand physics thoroughly MUST learn these
>theories, because they represent the current pinnacle of human
>accomplishment as far as physics goes.
Anyone who wants to understand the physical world better learn
physics, too; but he also ought to learn to ignore theoretical
physics.
>In a certain sense, everything we know about the fundamental laws
>of physics has been built into these two theories. The fact that
>these theories are not consistent with each other simply means we
>aren't done understanding physics yet.
Simply means we aren't (even close to) understanding physical
reality yet, John?
Glird http://members.gnn.com/glird/reality.htm
euejin_jeong
There is always a surprise. Who knows GR may be wrong in certain ranges of
physical reality. But I would guess it won't be easy to invalidate until
a few centuries to come. I guess SR has more clear room to improve. Especially in the part of the rest mass. It looks too rigid. There is no flexibility for
accomodation of the potential energy if anyone would like to do. My guess
is that it has all the inconsistencies in QFD concerning the rigidity of of
the coupling constant and the rest mass. Although renormalization scheme patchea little of flaws up in the theory. SUbstracting infinities and making sense
doesn't seem look strange to many physicist especially to those inclined to
the math side. I personally think math is very important in physics but it should never blurr the physical concept. Most of the time we should be able to tell
the magnitude of the physical quantity before calculation. Blind calculation
is the most dangerous practice in physics. One should know what one will get
before doing the calculation. The beauty in physics is that once the conceptual
framework is set, rest of the math is pretty much well defined.
However, recently the trend is reversed, which to me looks like a dangerous
path meaning a lot of waste of time is forseen.
We have much more mundane pebbles to pick. Those pebbles may show us how to
build the gigantic accelerator to test the future theories without too much
hassle. Actually I forsee it. Neutral particle accelerator may be feasible
according to the new theory with unlimited energy in a linac type machine.
Then we have exciting new testable theories and experiment to go along with.
Without a machine to test the new theories, we are not actually doing physics.
We are doing all kinds of speculations. That's all.
Ray Tomes
>Yes, it's true-- the curvature of general-relativistic spacetime can only
>be coupled to matter if that matter, itself, moves in a completely
>deterministic manner. And this is a big hole in general relativity.
Why are you so confident that the universe is not deterministic?
It seems to me that all evidence to the contrary has been found to be
unsubstantiated. The EPR tests do not hold water as evidence.
Is there anything else? On the other side there are results which
show that the supposed randomness of QM does have a deeper order.
-- Ray Tomes -- rto...@kcbbs.gen.nz -- Harmonics Theory --
http://www.vive.com/connect/universe/rt-home.htm
SavainL
Rams...@hermes.bc.edu (Keith Ramsay) writes:
>In article <4lbii0$2...@newsbf02.news.aol.com>, sav...@aol.com
>(SavainL) wrote:
>|For you guys to try to rationalize an obvious nonsense by using
>|ambiguous language like "incomplete" does not strike me as
>|particularly courageous.
>
>I don't remember anybody claiming bravery here....
Forgive me for making a wrong assumption.
>Spacetime is clearly not "obvious nonsense", so I think you must be
>misunderstanding it in some basic way. Spacetime is the set of all
>events, past, present and future. Not absurd at all.
Spacetime is indeed what you say it is. And that's precisely what makes
it absurd. It is an unchanging, motionless set. It forbids uncertainty.
Realities that demand either 100% uncertainty or 100% determinism are
equally absurd. It's like having a world where only 'left' is permitted
and 'right' is forbidden, or vice versa. It's nonsense! If this is not
obvious to you, what's the point of discussing it?
>I get the impression that you are somehow taking what somebody
>has said about spacetime (i.e., talking about events) as
>meaning some bizarre notion of future events being out there, already
>"given", fated or already present or something.
No one's ever told me that. But that's exactly what spacetime means
since nothing can move in spacetime. It's all preset. Are you
questioning this?
> In fact it is just an
>unfamiliar (to you) way of talking about events, including future
>ones.
Physicists teach that everything exists in spacetime. I've been hearing
it and reading about it for a long time. You call it unfamiliar. I call
it nonsense.
> For instance, the "set of cattle uncle Bob will own in 2025"
>refers to things which don't yet exist, but it's perfectly reasonable
>to talk about the collection anyway. It is just in the future. The
>same holds for parts of spacetime in our future. The events have not
>yet occurred, but in physics we may talk about them anyway.
I fail to see the point of this. You say it does not exist (and I
agree) yet most physicists say that not only does it exist, it can be
curved by matter and it can affect the motion of matter. Which is it?
Either it exists or it doesn't. Make up your mind.
>|Baez is right on in this respect. Spacetime *is* false.
>
>He said general relativity and the standard model are "false". I
>don't recall him saying spacetime is false.
Well Baez said this:
>[...] The main reason I am interested in quantum gravity is that it
>is bound to completely shatter the picture of spacetime given to us by
>previous theories: Aristotelian and Newtonian physics, special and
>general relativity.
To me, it sounds very much like he's not happy with spacetime. I was
just agreeing with him there. Are we talking about a different Baez? Or
are you just nitpicking because you don't like what I've been saying about
spacetime?
>There are two types of objections here. One is the objection to
>teaching hypothetical, theoretical ideas, which are bound someday
>to be revised, as if they were simply true. On this we largely
>agree. Certainly I agree that GR is bound to be revised as physics
>progresses. This is what people are talking about when they say that
>the theory is "incomplete". People are not rationalizing about this
>here; we're acknowledging your point.
>On the other hand, there is your claim that the theory was an awful
>theory from the outset, obviously bad, because of some vague
>apprehensions about space-time. People are *not* trying to
>rationalize this point either, by saying GR is incomplete. It's
>not relevant. If the idea were so bad, being incomplete wouldn't
>make it any better. Nobody says it would.
To tell you the truth, I don't really care all that much about GR. The
point of this thread is spacetime. Spacetime is absurd whether or not it
may shatter your world view. If GR is based 100% on the validity of
spacetime, then I would not say that it needs to be revised because it is
simply incomplete. I would say that it needs to be completely *replaced*
by a new theory that is not based on spacetime. Period.
>We are simply telling you that this "problem" you think GR has,
>that other theories do not have, is simply not a problem. You
>think you've seen a problem, but you are simply confused. And
>apparently somewhat overconfident of your understanding of the
>matter.
It's more than a problem. It's a scandal. I've made some specific
objections to spacetime that you have completely ignored and instead you
are confusing the issue by claiming that I don't understand it. That's a
really lame argument, Keith. I could easily say the same about you and I
would probably be right. As I mentioned in another folder, creationists
could claim victory by accusing you of not understanding that the whole
universe was created in 4004 BC.
> Do you really think the physics community is a bunch
>of total idiots?
Well, believe it or not, I'm beginning to seriously ask myself this very
question. I've seen a few things written on sci.physics *by physicists*
that are not too flattering, to say the least. And I can quote chapter
and verse if I have to. You're right though. I would never say that
physicists are total idiots. Many of them certainly do show some signs of
idiocy in certain areas.
But then again, it could be idiocy, fear, pride, vanity, or just plain
mule-headedness. I really don't care. We all suffer from one shortcoming
or another. I'm looking for a few people who can see the absurdity of
spacetime and have a serious discussion about it. If needs be, the
discussion can be carried off line so as not to offend the sensibilities
of some physicists. I say "some" because not all would be offended. I
already know of several physicists who agree with me on spacetime. Or
rather, I should say that I agree with *them* on spacetime. And no, they
are not total idiots. Only partially, just like everyone else.
Oz
writes
>
>In a certain sense, everything we know about the fundamental laws of
>physics has been built into these two theories. The fact that these
>theories are not consistent with each other simply means we aren't done
>understanding physics yet.
Luckily for theoretical Physicists at the 'cutting edge', who would
otherwise have to tackle more mundane tasks. Say, like the genesis and
evolution of the universe. :-)
I don't think they would be safe to let loose on particle accelerators
of humungous power. :-)
Oz
writes
> Baez:
>> For instance, the "set of cattle uncle Bob will own in 2025"
>>refers to things which don't yet exist, but it's perfectly reasonable
>>to talk about the collection anyway. It is just in the future. The
>>same holds for parts of spacetime in our future. The events have not
>>yet occurred, but in physics we may talk about them anyway.
>
> I fail to see the point of this. You say it does not exist (and I
>agree) yet most physicists say that not only does it exist, it can be
>curved by matter and it can affect the motion of matter. Which is it?
>Either it exists or it doesn't. Make up your mind.
I think you are missing the point, by a mile.
When we line up our piece of artillery we work out the path of the shell
*into the future* to work out where it will land. You could do the same
thing using spacetime, of course. However should you then change your
aim or even decide not to fire it you wouldn't expect the world to end.
There is no difference between doing this calculation using spacetime
and using conventional mathematics. Why do you think there should be?
Your problem has at it's root the absolute determination of the future
by the configuration of the present. This was (I think) the idea of
Lagrange and was much argued about until QM made this patently
inapplicable. Using spacetime as a convenient way of visualising and
calculating physical processes is philosophically no different to using
Newtonian methods. No magic involved.
Keith Stein
>of total idiots?
In article <4ledlt$r...@newsbf02.news.aol.com>, SavainL
Well, believe it or not, I'm beginning to seriously ask myself this
very question. I've seen a few things written on sci.physics *by
physicists* that are not too flattering, to say the least. And I can
quote chapter and verse if I have to. You're right though. I would
never say that
physicists are total idiots.
But then again, it could be idiocy, fear, pride, vanity, or just plain
mule-headedness. I really don't care. We all suffer from one
or another. I'm looking for a few people who can see the absurdity of
spacetime and have a serious discussion about it. If needs be, the
discussion can be carried off line so as not to offend the sensibilities
of some physicists. I say "some" because not all would be offended. I
already know of several physicists who agree with me on spacetime. Or
rather, I should say that I agree with *them* on spacetime. And no,
they are not total idiots. Only partially, just like everyone else.
Best regards,
Louis Savain
keith stein wrote:-
'I do not understand.' It was someone quite else that wrote;
'You do not understand', if you understand me, Louis, but i
hope you don't mind my slight editing of your reply to them,
which i thought was excellent.
in reply to me Louis Savain writes:-
> Time, viewed as a spatial dimension, is indeed 100% nonsense
i agree it is 'nonsense' to view 'time' as a 'spatial dimension'.
> It is unfortunate that physicists and philosophers
>have taken to dimensionalizing time.
>
Well i'm not quite sure what you mean by 'dimensionalizing time',
but in the sense that physicists make time 'measurable' with clocks,
i consider this to be their job, rather than unfortunate.
--
Keith Stein
john baez
>In article <4lf30d$6...@newsbf02.news.aol.com>, SavainL <sav...@aol.com>
>writes
>> Baez:
>>> For instance, the "set of cattle uncle Bob will own in 2025"
>>>refers to things which don't yet exist, but it's perfectly reasonable
>>>to talk about the collection anyway. It is just in the future. The
>>>same holds for parts of spacetime in our future. The events have not
>>>yet occurred, but in physics we may talk about them anyway.
>> I fail to see the point of this. You say it does not exist (and I
>>agree) yet most physicists say that not only does it exist, it can be
>>curved by matter and it can affect the motion of matter. Which is it?
>>Either it exists or it doesn't. Make up your mind.
>
>I think you are missing the point, by a mile.
What's that "Baez" doing up there? I didn't write any of that stuff.
Edward Green
>Why do you want to understand, much less "expain", a false
>theory. BTW, thanks for announcing your admittedly expert opinion
>that "it's false". Good for you!
Pouncing on isolated words leads to polarization of argument and breakdown
in free communciation. It's like tabloid journalism... reporter hurredly
scripples down remark by prominent physicist, runs to call in front page
story: "JOHN BAEZ BELIEVES GR IS FALSE!". (Baez leaves country one step
ahead of agents of the GR conspiracy seeking revenge.)
Oz
writes
>In article <$1GgnoAH...@upthorpe.demon.co.uk> O...@upthorpe.demon.co.uk
>writes:
>>In article <4lf30d$6...@newsbf02.news.aol.com>, SavainL <sav...@aol.com>
>>writes
>
>>> Baez:
>>>>refers to things which don't yet exist, but it's perfectly reasonable
>>>>to talk about the collection anyway. It is just in the future. The
>>>>same holds for parts of spacetime in our future. The events have not
>>>>yet occurred, but in physics we may talk about them anyway.
>
>>> I fail to see the point of this. You say it does not exist (and I
>>>agree) yet most physicists say that not only does it exist, it can be
>>>curved by matter and it can affect the motion of matter. Which is it?
>>>Either it exists or it doesn't. Make up your mind.
>>
>
>What's that "Baez" doing up there? I didn't write any of that stuff.
Oh shit. I cocked it up. I misread the post and thought that was
Savaint's quote of the mighty wizard. I must admit it seemed odd at the
time. It didn't have the mighty one's elan.
Grovelling apologies.
Sackcloth and ashes for the rest of the week.
I will self flagellate daily too.
And prostrate myself towards California every four hours.
And eat Hubanos chillies neat.
Is that enough? Oh high and mighty one? :-{
NB Hic. :-)
Keith Stein
writes
> All this "incompleteness of GR / QT" stuff
>is only a matter of principle. There were QT matters, GR doesn't play
>a role at all and vice versa. It is only in EXTREMELY strange and weird
>places (like the first billionth of second of the big bang - or tiny
>black holes) that both of them play a role. These weird places are
>"at the Planck scale".
>If you're a practical guy, you say: GREAT ! So we actually know
>everything (in principle) except for these weird places we'll never
>study anyhow.
>If you are a philosopher, you say SHIT ! We have a principal
>inconsistency between GR and QT, and no experiment in the coming
>500 years (rough guess :) is going to address these matters, so
>we will not know.
>And if you're a crackpot, you silently solve the problem and you
>tell the world that TIME IS BOILING EGG :-)
Cheers,
Patrick.
Albert Einstein: mass is energy.
Patrick Van Esch: Time is egg (a boiling one)
--
Patrick Van Esch
http://www.iihe.ac.be/hep/pp/vanesch
mail: van...@dice2.desy.de
for PGP public key: finger van...@dice2.desy.de
>
>That is the "practical guy viewpoint". The rest is indeed just a matter
>of taste. I more or less adopt the same philosophy, because it must be
>way frustrating to FINALLY UNIFY GR AND QT, and none of your new
>predictions will be verified in the coming 500 years (if ever). We
>actually have (a few thousand) candidate unifications: that's what
>string theory is all about. But the people who work on that NOW will
>never see it confirmed or rejected. Must be a pretty hard thing to
>swallow I guess....
>
>Of course, when I say this to a string theorist, he quite rightly
>corrects me: How can you know ? Right, it MIGHT be that some very
>accessible effect is predicted only by string theory. But I don't
>think so !
>
>> Obviously I haven't been able to catch the real twist. So I have to ask
>you
>> to try to enlighten me further. Will you? Thanks in advance.
>>
>On the contrary, I think you have a rather good view on it.
>
>cheers,
>Patrick.
>
>PS: I won't post this again, I just mailed it to you. You can post it
>if you want to, but here, both of my newsservers are utterly confused
>(the one in Brussels and the one in DESY).
>
>
>Lorenz Borsche (FRG)
>
>Dubium sapientiae initium. [Descartes]
--
Keith Stein
Just so everone knows which crackpot we are talking about.
SavainL
<sth...@sthbrum.demon.co.uk> writes:
>[...]
> 'I do not understand.' It was someone quite else that wrote;
> 'You do not understand', if you understand me, Louis, but i
> hope you don't mind my slight editing of your reply to them,
> which i thought was excellent.
I get the slight feeling that you're using my posts for your own crusade
against physicists. If you are, please reveal it as such as I have
nothing against physicists in general. My beef is with a few absurd
notions and inconsistencies. Spacetime is but one of them.
>in reply to me Louis Savain writes:-
>> Time, viewed as a spatial dimension, is indeed 100% nonsense
>
>i agree it is 'nonsense' to view 'time' as a 'spatial dimension'.
>
>> It is unfortunate that physicists and philosophers
>>have taken to dimensionalizing time.
>>
>Well i'm not quite sure what you mean by 'dimensionalizing time',
>but in the sense that physicists make time 'measurable' with clocks,
>i consider this to be their job, rather than unfortunate.
You're right of course. Thanks for pointing out the ambiguity in my
wording. In this context, I meant to say "spatializing time". By this I
mean that physicists have taken to giving time an independent existence,
apart from motion and distance. Motion and distance, in my opinion, are
the only things with an independent existence. Time is but a ratio of
distance over motion.
john baez
>Grovelling apologies.
>Sackcloth and ashes for the rest of the week.
>I will self flagellate daily too.
>And prostrate myself towards California every four hours.
>And eat Hubanos chillies neat.
>Is that enough? Oh high and mighty one? :-{
No need for all that. Just calculate the Ricci tensor of the big bang
cosmology, starting from your nice-looking results on the Riemann
tensor? All you need to do is sum over a, below:
R_{bc} = R^a_{bac}
Just think how good you will feel when you can say you've used general
relativity to figure out the equations governing the expansion of the
universe!
Tom Potter
> Time, viewed as a spatial dimension, is indeed 100% nonsense as I've
>pointed out elsewhere. It is unfortunate that physicists and
philosophers >have taken to dimensionalizing time.
You have made a couple of key points in this forum:
1. Is the position of an electron intrinsic or extrinsic?
2. Nothing moves in time-space.
BUT I think that you are off base in saying that time should not be
combined with space and dimensionalized.
It is my observation that the fundamental unit of observation
and of information is the cycle.
Time, space, mass and all other properties can be ( And should be )
defined in terms of a single reference cycle.
time(X) = cycles(reference) / cycles(X)
distance(X) = interaction time(X) * C
mass(A) * G = distance(B)^3 / time^2
Note that all other properties can be defined in terms
of the three developed above. ( Time, distance and mass )
Also, there is no zero, nor infinity, as all "points"
must be referenced to some standard cycle. As I have
also posted, any other point ( Time, space, mass, etc )
can be most effectively referenced using a binary search
about a circle.
All things other than cycles, and cycle ratios
are creations of the mind.
Visit my Web site at: http://pobox.com/~tdp
for detailed articles on each of these subjects.
Tom Potter
Scott Ellsworth
>In article <Ramsay-MT-210...@delphi.bc.edu>,
>Rams...@hermes.bc.edu (Keith Ramsay) writes:
>
>>In article <4lbii0$2...@newsbf02.news.aol.com>, sav...@aol.com
>>(SavainL) wrote:
>>Spacetime is clearly not "obvious nonsense", so I think you must be
>>misunderstanding it in some basic way. Spacetime is the set of all
>>events, past, present and future. Not absurd at all.
>
> Spacetime is indeed what you say it is. And that's precisely what makes
>it absurd. It is an unchanging, motionless set. It forbids uncertainty.
>Realities that demand either 100% uncertainty or 100% determinism are
>equally absurd. It's like having a world where only 'left' is permitted
>and 'right' is forbidden, or vice versa. It's nonsense! If this is not
>obvious to you, what's the point of discussing it?
Please. Do not continue to. You have stated your position clearly
enough that anyone who has followed the thread now knows what you think
about spacetime and physics. You have stated (paraphrased) that if
spacetime is needed for a theory, and that theory makes useful
predictions, you will reject the theory rather than accept spacetime, as,
by assumption, spacetime is not true.
It is clear at this point that you have some internal objection to any
predeterministic theory, and that you have concluded that spacetime is
such. As usually presented, BTW, I agree with the second half of your
statement, though that is not relevant to us - we are not in a
position to see the predetermined paths. Consider, even if all of our
actions are predetermined by paths through spacetime and physical laws,
**we** do not have access to the information needed to determine what
will be.
We may well live in a completely predetermined universe, which appears
random. Or we may not, as some QM results would may indicate. Wheeler's
many worlds approach to QM is deterministic in large scale as well, but
last time I checked, there was no way to distinguish Copenhagen and Many
Worlds.
I agree with you - there is really no point in contiuing this
discussion. You have assumed the lack of existence of a major component
of a theory, as usually presented, and therefore cannot communicate with
the reltavists at all. You have assumed the theory which gives the best
predictive value out of existence. Because it does give better
predictions than any other, it can and will be taught, until a better
model comes along.
Scott
--
_____________________________________________________________________________
Scott Ellsworth q...@netcom.com
My opinions are my own EViews ftp: ftp.netcom.com:/pub/qm/qms
Quantitative Micro Software - 714 856 3368
"The barbarian is thwarted at the moat" - Scott Adams
Tom Potter
(Keith Ramsay) writes:
>
>
>In article <4lbii0$2...@newsbf02.news.aol.com>, sav...@aol.com
(SavainL) wrote:
ambiguous
>|language like "incomplete" does not strike me as particularly
courageous.
>
>I don't remember anybody claiming bravery here....
>
>misunderstanding it in some basic way. Spacetime is the set of all
>events, past, present and future. Not absurd at all.
Okay, we have matter, and we have time-space.
Now what is an event?
The collapse of the wave function?
If so, what is an event in GR?
Tom Potter
Ilja Schmelzer
>I'm looking for a few people who can see the absurdity of
>spacetime and have a serious discussion about it.
"curved spacetime" is not an absurdity, but a highly suggestible word
which obviously confuses most laymen but probably even many
scientists.
Choosing another word to describe the same thing, like "time
measurement distortion by gravity" (also suggestible, but in another
direction) would be better.
Indeed, gravity is a universal force, there is nothing strange with
the assumption that it has an influence on time measurement with
clocks. There is no gravitational charge, that's why it has the same
influence on all measurements we can do. Thus, we have no possibility
to measure an "undistorted" time and to compare it with the "clock
time". Having only distorted clocks, we cannot even measure
contemporaneity of different events.
The things we cannot measure are not part of the GR equations, and GR
uses the notion "proper time" for what I prefer to name "distorted
time measurement", because there is no time measurement better than
proper time. That's all. No absurdity.
In future we may learn about "hidden variables" we cannot observe now.
There may be absolute time, absolute space and contemporaneity, filled
by an ether which has a velocity. See ~/PG/PG.html for an example of
such a "hidden variable theory".
Ilja
--
My concept for the quantization of gravity: ~/PG/index.html
--------------------------------------------------------------------------
Ilja Schmelzer, D-10178 Berlin, Keibelstr. 38, <schm...@wias-berlin.de>
WWW: ~/index.html "~" means http://www.berlinet.de/schmelzer
--------------------------------------------------------------------------
Ilja Schmelzer
writes
>
>In a certain sense, everything we know about the fundamental laws of
>physics has been built into these two theories. The fact that these
>theories are not consistent with each other simply means we aren't done
>understanding physics yet.
For PG, I see no reason to say it is not consistent with quantum
theory.
Of course, it is a nonlinear field theory, but a classical one, with
well-defined space and time, a Hamiltonian, well-defined evolution.
The "Shocker" mentioned in the Subject line is GR only, not present in
PG.
The difficulties with the sqrt(-g) may be solved using a "triade"
formalism similar to the "tetrade formalism" of GR (simply by using
the subdivision into space and time defined in PG), with the compact
group SO(3) instead of the Lorentz group as gauge group.
LBsys
>By this I
>mean that physicists have taken to giving time an independent existence,
>apart from motion and distance. Motion and distance, in my opinion, are
>the only things with an independent existence. Time is but a ratio of
>distance over motion.
Now, Louis, why didn't you say this first hand. I mean, that would have
explained a lot of things, wouldn't it?
Now we might be able to discuss the right thing: is there motionless time?
Make a new thread of it, could be interesting.
Cheerio
Oz
writes
Oh! You should have said earlier. (Ducks)
As it happens I posted my feeble efforts earlier today. Unfortunately
time is tight this week so it's been dreadfully rushed and I'm not at
all happy with it.
I mean, what's the point of having journeyman wizards all over the place
if they make the poor old apprentice do it? Well, he has to admit that
it's good for his soul. (And quite fun too, but he isn't admitting it).
He is going to get some serious stick over his posting, though.
Matthew J. McIrvin
> I would suspect the quantum gravity to evolve as a rather minor
> 'correction factor' in reality. Don't get me wrong: All I'm saying is that
> counted out on a big scale, we might still use GR formulas like we do now
> use Newtonion eqns, when we expect GR effects to be neglectable. Or am I
> thinking complete in the wrong direction?
Gravitational effects are only large when *tremendous* masses, like
planets and stars, are involved. The motions of such bodies are classical
to a high degree of precision. We can't even do a "Schrodinger's cat"
sort of experiment with the motion of a planet, though it apparently *is*
possible to do it with masses, like bowling balls, which are big enough to
have measurable gravitational effects.
So, yes, quantum gravity effects aren't likely to be large, and general
relativity will be used even if quantum gravity gets worked out, and for
exactly the same reason that we still use Newtonian mechanics. GR will
still have a huge domain of legitimate application.
--
Matt McIrvin http://world.std.com/~mmcirvin/
--
Nntp-Posting-Host: world.std.com
Path: mmcirvin
Date: Sat, 30 Mar 1996 02:41:04 -0500
From: mmci...@world.std.com (Matt McIrvin)
Stephen Paul King
> 'You do not understand', if you understand me, Louis, but i
> hope you don't mind my slight editing of your reply to them,
> which i thought was excellent.
>
>
>
>>have taken to dimensionalizing time.
>>
>but in the sense that physicists make time 'measurable' with clocks,
>i consider this to be their job, rather than unfortunate.
>
>Keith Stein
Humm,
What ever happend to my postings "About Time?"
Stephen
SavainL
writes:
>[...]
>You have stated (paraphrased) that if
>spacetime is needed for a theory, and that theory makes useful
>predictions, you will reject the theory rather than accept spacetime,
>as, by assumption, spacetime is not true.
I never said that. The part " and that theory makes useful
predictions" is your own invention.
>I agree with you - there is really no point in contiuing this
>discussion. You have assumed the lack of existence of a major
>component of a theory, as usually presented, and therefore cannot
>communicate with the reltavists at all.
True to a certain extent. By the way I really have no problem with SR
as SR does not require a curved spacetime. As someone else explained in
another thread I consider the spacetime of SR simply as a graphing aid.
BTW, are general relativists the only people on sci.physics that it would
make any further discussions unnecessary. I don't think so. If you don't
like discussions about the stupidity of spacetime, put it in your kill
file. This way I won't worry too much about offending you and you won't
get offended. BTW, sorry if I offended you.
>[...]
> You have assumed the theory which gives the best
>predictive value out of existence. Because it does give better
>predictions than any other, it can and will be taught, until a better
>model comes along.
I really don't care all that much. As I mentioned elsewhere, it's
relatively easy to come up with equations that fit observed reality. It
seems to be an "after the fact" kind of thing. Newton did come up with
some beautiful equations after he studied Kepler's painstakingly
accumulated data, among others. Extrapolating that one has a sensible
theory (i.e., that one understands what's really going on) from these
equations is uh.. exaggerating a little, maybe? Newton had his "action at
a distance" and general relativists have their "curved spacetime". Only
Newton was careful enough to say that bodies behave *as if* there were
action at a distance. In his "Principia" he didn't categorically insist
that we should accept action at a distance. GR proponents, on the other
hand, blatantly teach that spacetime curvature *is* the cause of inertial
motion. We must accept it or else we don't understand it. A touch of
arrogance I would say.
SavainL
schm...@fermi.wias-berlin.de (Ilja Schmelzer) writes:
>In article <IpFmlHA0...@sthbrum.demon.co.uk> Keith Stein
><sth...@sthbrum.demon.co.uk> writes:
>
>>I'm looking for a few people who can see the absurdity of
>>spacetime and have a serious discussion about it.
Sorry, Keith Stein didn't write that, I did.
>"curved spacetime" is not an absurdity, but a highly suggestible word
>which obviously confuses most laymen but probably even many
>scientists.
It seems to confuse scientists just as much as laymen as the thread
"Inertial Motion: Fact or Fiction?" clearly shows. They can't even
explain it to themselves.
>Choosing another word to describe the same thing, like "time
>measurement distortion by gravity" (also suggestible, but in another
>direction) would be better.
If it were just a matter of graphing the result of observations, I would
not have any problem with it. The problem pops up when the graph suddenly
takes a life of its own and begins to affect moving bodies. That's
another absurdity that should be added to the list of absurdities.
>Indeed, gravity is a universal force, there is nothing strange with
>the assumption that it has an influence on time measurement with
>clocks. There is no gravitational charge, that's why it has the same
>influence on all measurements we can do. Thus, we have no possibility
>to measure an "undistorted" time and to compare it with the "clock
>time". Having only distorted clocks, we cannot even measure
>contemporaneity of different events.
>
>The things we cannot measure are not part of the GR equations, and GR
>uses the notion "proper time" for what I prefer to name "distorted
>time measurement", because there is no time measurement better than
>proper time. That's all. No absurdity.
I'm sorry. Have you taken a closer look at what has been posted here?
The original absurdity in question has nothing to do with the above. It
has to do with a "motionless spacetime".
SavainL
>[...]
>It is clear at this point that you have some internal objection to any
>predeterministic theory, and that you have concluded that spacetime is
>such. As usually presented, BTW, I agree with the second half of your
>statement, though that is not relevant to us - we are not in a
>position to see the predetermined paths. Consider, even if all of our
>actions are predetermined by paths through spacetime and physical laws,
>**we** do not have access to the information needed to determine what
>will be.
One of the biggest conceptual problems with a predeterminded, motionless
spacetime is that there is no way to determine by "looking" at it, *where*
the present is. The present seems to reside everywhere along the time
dimension. What mechanism does the theory provide to make such an
important observation? In other words, what differentiates the future
from the past? What is the meaning of 'now' in spacetime? I strongly
suspect spacetime provides no answers to these questions.
A more plausible alternative is that only the 'now' exists. The
question then becomes, "what is meant by the 'now' or 'present'?" If
physicists could provide a logical answer to this question, then I would
be really impressed.
>We may well live in a completely predetermined universe, which appears
>random. Or we may not, as some QM results would may indicate.
>Wheeler's many worlds approach to QM is deterministic in large scale as
>well, but last time I checked, there was no way to distinguish
>Copenhagen and Many Worlds.
You and I both know that this "many worlds" hypothesis is just a feeble
attempt to escape from the unforgiving determinism of spacetime. How are
these "many worlds" mapped onto spacetime, one might ask? And how does
one jump from one to the other? At what point in spacetime? If the
picture is becoming very complicated very fast, it's because it is. IMO,
the "only-now-exists" hypothesis is orders of magnitude simpler and thus
it is much more in keeping with the spirit of Occam's razor.
I have no problem with a reality that requires partial determinism and
partial uncertainty. Such a reality makes logical sense to me. The
complementarity (the oneness, if you will) of determinism/uncertainty
cannot be denied. Both are needed. One without the other is like 'up'
without 'down'. I've mentioned this before but it bears repeating.
Keith Ramsay
In article <4lf30d$6...@newsbf02.news.aol.com>, sav...@aol.com (SavainL) wrote:
|>Spacetime is clearly not "obvious nonsense", so I think you must be
|>misunderstanding it in some basic way. Spacetime is the set of all
|>events, past, present and future. Not absurd at all.
|
| Spacetime is indeed what you say it is. And that's precisely what makes
|it absurd. It is an unchanging, motionless set. It forbids uncertainty.
You're pulling this out of thin air. Talking about sets of events which
have not occurred yet does not "forbid uncertainty" with regard to them.
...
|>I get the impression that you are somehow taking what somebody
|>has said about spacetime (i.e., talking about events) as
|>meaning some bizarre notion of future events being out there, already
|>"given", fated or already present or something.
|
| No one's ever told me that. But that's exactly what spacetime means
|since nothing can move in spacetime. It's all preset. Are you
|questioning this?
I am denying it. Talking about the future does not mean that it is "preset".
"Pre" implies that there is some situation at an earlier time which sets it.
Talking about spacetime is nothing more than a way of talking about the
past, present, and future. The confusion comes in when one assumes that
there is something more going on than that.
Keith Ramsay
SavainL
>[...]
>Spacetime *is* real because "spacetime" is *defined* as *the set of all
>physical events*. The spatial and temporal relationships between
>physical events are then arranged in GR in a way that on paper looks
>the same way as the description of relationships between points in
>curved spaces. That doesn't mean that "spacetime is some stuff that's
'really' bending."
I am a believer in cause and effect. If you tell me that the motion of
matter is affected by spacetime then I take it that you mean that that the
spacetime is the cause and that it's real. But...
>All that a statement like "spacetime is curved" really means is that
>the spatial and temporal relationships obey certain rules that happen
>to look completely analogous *AS IF* we were dealing with "stuff"
>that's "bending."
Gosh! That's exactly the point I've been making all over the place,
Jan. If GR proponents are saying that things act *as if* there were
spacetime curvature, I would say "HURRAY! I ACCEPT IT! I will accept
spacetime curvature as a mapping of events and no more. At least until a
more fundamental cause-and-effect theory is found". I HAVE NO PROBLEM
WITH THAT!
But you are the *only* one saying that, Jan. Everyone else is
ascribing a separate reality to spacetime. And I have a problem with
that. This whole discussion started when I asked "what is the cause of
motion?" John Baez said it was this living thing out there called
"spacetime metric" and that's where Einstein's genius came in. He teaches
a course in GR for God's sake! Doug Meritt came out and said essentially
the same thing. And that's exactly what I've been hearing and reading
about all along. Why could *not* John Baez and all the books I've been
reading say the same thing that you're saying? Why did you *not* correct
him when he posted his stuff? Why attack me when I'm objecting to it
because it does not make sense?
Why has it taking this long for someone to come out and say what I've
been saying all along? You are the physicists. I'm supposed to take your
word and you are all saying different things. Why the confusion?? Why do
you physicists go out of your way to confuse the layfolks? Why have you
allowed me to get all worked up over this when you knew all along that
spacetime is just a "mapping" of events?
Please come out and tell me, all of you, that you do not ascribe a
***cause and effect reality*** to spacetime and I will definitely accept
it and study it further. Heck I'll apologize to everybody and I'll study
the math too. But as John Baez explained it it does not make sense.
Keith Stein
writes
> I really have no problem with SR
>as SR does not require a curved spacetime.
Sure it does Louis.........................
As soon as you make 'c+v=c'
you gotta twist hell out of space and time
to make the sums work out; AM I RIGHT?
> As someone else explained in
>another thread I consider the spacetime of SR simply as a graphing aid.
!!!!! 'graphin hinderance' would be nearer the mark.
>BTW, are general relativists the only people on sci.physics
????? i wondered about that one myself.
>Newton was careful enough to say that bodies behave *as if* there were
>action at a distance. In his "Principia" he didn't categorically insist
>that we should accept action at a distance. GR proponents, on the other
>hand, blatantly teach that spacetime curvature *is* the cause of inertial
>motion. We must accept it or else we don't understand it. A touch of
>arrogance I would say.
>Louis Savain
Nice one Louis!
Keith Stein
Ilja Schmelzer
>>All that a statement like "spacetime is curved" really means is that
>>the spatial and temporal relationships obey certain rules that happen
>>to look completely analogous *AS IF* we were dealing with "stuff"
>>that's "bending."
> Gosh! That's exactly the point I've been making all over the place,
>Jan. If GR proponents are saying that things act *as if* there were
>spacetime curvature, I would say "HURRAY! I ACCEPT IT! I will accept
>spacetime curvature as a mapping of events and no more. At least until a
>more fundamental cause-and-effect theory is found". I HAVE NO PROBLEM
>WITH THAT!
>But you are the *only* one saying that, Jan.
Not the only one, me too :-).
>Everyone else is
>ascribing a separate reality to spacetime. And I have a problem with
>that.
With "reality"? I think, the events (thus spacetime) are real too.
I don't think it is "really bending".
>This whole discussion started when I asked "what is the cause of
>motion?" John Baez said it was this living thing out there called
>"spacetime metric" and that's where Einstein's genius came in. He teaches
>a course in GR for God's sake! Doug Meritt came out and said essentially
>the same thing. And that's exactly what I've been hearing and reading
>about all along. Why could *not* John Baez and all the books I've been
>reading say the same thing that you're saying? Why did you *not* correct
>him when he posted his stuff?
Because he is not really wrong. I cannot prove that the spacetime is
not "really curved", as much as he cannot prove that the spacetime is
"really curved".
If somebody is posting stuff saying nonsense in this direction, I
usually reply, if I read it.
> Why attack me when I'm objecting to it because it does not make sense?
If you say "it does not make sense" you are wrong.
>Why has it taking this long for someone to come out and say what I've
>been saying all along? You are the physicists. I'm supposed to take your
>word and you are all saying different things. Why the confusion??
This is because there are established things - the experimental
predictions - and a lot of stuff around which is not certain -
interpretation.
Unfortunately it is hard to explain something to laymen without using
one of the possible interpretations.
>Why do
>you physicists go out of your way to confuse the layfolks? Why have you
>allowed me to get all worked up over this when you knew all along that
>spacetime is just a "mapping" of events?
Many scientists have simply not recognized that there may be other
interpretations are possible in GR and explain only the standard
interpretation from Einstein. In quantum mechanics the situation is
better - people usually say clearly which things depend on the
interpretation.
In my own interpretation of GR the tensor field g_ij describes the
ether, which is not stationary but interacts with material fields.
The influence material -> ether -> other material is gravity. There is
an absolute time and an absolute space. (Exactly speaking, this is not
GR itself, but a slightly different theory which I have named
post-relativistic gravity, but the experimental predictions are
de-facto the same.)
> Please come out and tell me, all of you, that you do not ascribe a
>***cause and effect reality*** to spacetime and I will definitely accept
>it and study it further. Heck I'll apologize to everybody and I'll study
>the math too. But as John Baez explained it it does not make sense.
Sorry, cause and effect are connected with spacetime. At least in the
following sense: There is some event which may have a causal influence
on some other event. We can do now a lot of measurements using clocks,
light and so on, and based on these measurements we can decide if such
a causal connection is possible.
We don't know what we really measure with our clocks, we don't know
why this is true, we don't know if it remains true in the quantum
theory. But nonetheless "spacetime" - the mapping of events with their
distances measured by clocks - is connected with cause and effect.
John Baez explanations make sense. It is simply another interpretation
of the same theory.
SavainL
<sth...@sthbrum.demon.co.uk> writes:
>In article <4ljg4d$m...@newsbf02.news.aol.com>, SavainL ><sav...@aol.com>
writes
>> I really have no problem with SR
>On the contrary Louis; THAT *is* YOUR PROBLEM
>
>>as SR does not require a curved spacetime.
>Sure it does Louis.........................
> As soon as you make 'c+v=c'
> you gotta twist hell out of space and time
> to make the sums work out; AM I RIGHT?
Probably but I don't know at this point. I'm just now digging deeply
into the math of it. Give me some time. I do have a habit of being very
thorough in certain things. So far, my books tell me that the spacetime
of SR is flat. But after my experiences here on this forum, I'm not
taking anyone's word anymore, especially physicists. At any rate, here's
my *current* take on the spacetime of both GR and SR:
It is entirely an operational spacetime. It is a mapping resulting from
observations, i.e., measurements. Nothing else. It has no *reality*,
i.e., it does not exist *out there*. It really explains nothing other
than the observational "what" of things. Very little that makes any sense
is ever said about the "why" of things. In this narrow sense, it's no
different than Newtonian mechanics. As such, I'll go along with it for
the time being. The real thing that's out there is still undiscovered.
In other words, physicists are still looking at reality through a very
dark glass.
What turns me off is the arrogance of "superior knowledge" that some
physicists exhibit. Most physicists rarely come out and say "we don't
really know". When I ask a question that has no known answer, they feel
that it's their privilege as physicists to provide an answer and if *they*
don't have the answer, no one else does and no one else but them had
better dare come up with one. Talk about having primitive territorial
instincts! Or worst, they confuse and obsfucate the hell out of things
and accuse you of not understanding. Heck, if it's so hard to understand
without a thorough study into complex convoluted structures, why try to
explain it at all? Mind you, not all of them are like that. Just the
most vociferous ones.
Scott Ellsworth
need to continue.
In article <4ljkus$o...@newsbf02.news.aol.com>, SavainL <sav...@aol.com> wrote:
>In article <qmsDq9...@netcom.com>, q...@netcom.com (Scott Ellsworth)
>writes:
>
>>[...]
>>It is clear at this point that you have some internal objection to any
>>predeterministic theory, and that you have concluded that spacetime is
>>such. As usually presented, BTW, I agree with the second half of your
>>statement, though that is not relevant to us - we are not in a
>>position to see the predetermined paths. Consider, even if all of our
>>actions are predetermined by paths through spacetime and physical laws,
>>**we** do not have access to the information needed to determine what
>>will be.
>
> One of the biggest conceptual problems with a predeterminded, motionless
>spacetime is that there is no way to determine by "looking" at it, *where*
>the present is. The present seems to reside everywhere along the time
>dimension. What mechanism does the theory provide to make such an
>important observation? In other words, what differentiates the future
>from the past? What is the meaning of 'now' in spacetime? I strongly
>suspect spacetime provides no answers to these questions.
But there is an implicit "now" in the structure of spacetime, from the
view of anything imbedded in it. To them, the t coordinate is thier
"now." That it is difficult to have two people agree on what "now" is
given differing velocities and accelerations merely means that the
present is not easy to define. Newton thought it was. Hawking does not.
Now if you mean that, from the point of view of someone outside
spacetime, there is no way to select a given point along the t axis as
the present, I suspect you are quite right. I would be terribly
surprised if any time coordinate in spacetime mattered from that
perspective.
> A more plausible alternative is that only the 'now' exists. The
>question then becomes, "what is meant by the 'now' or 'present'?" If
>physicists could provide a logical answer to this question, then I would
>be really impressed.
Well, it depends on just what you want out of your present. Do you want
one that makes sense to you, or to an observer independent of time? (By
the way, I got into this argument with a priest over free will,
determinism, and predestination when I was eight or nine, so I do not
think that physics alone has tackled the problem. Physics merely has a
very precise vocabulary (mathematics) and a final appeal to experiment as
fundemental tools. Other ways of inquiry use different techniques, and
come to different answers. To the best of my knowledge, physics rarely
attempts to answer questions about a hyperrealm in which some kind of
meta time takes place, and satisfies itself with exploring the universe
we can measure.
I am going to indulge, and wax philosophical for a moment. From one
point of view, the entire universe could be considered a single object,
including the past, present, and future. To a being living inside it,
it is a dynamic thing, since as time passes, things change, but to a
being outside it, it is as dynamic as a pencil line drawn on paper. Part
of am aesthetically pleasing picture, one hopes, but a finished work.
I, too, would be impressed by any understanding of the matrix in which
the universe exists. I am not holding my breath, though, because it
seems likely that there are singularities between us and any outside realm.
>>We may well live in a completely predetermined universe, which appears
>>random. Or we may not, as some QM results would may indicate.
>>Wheeler's many worlds approach to QM is deterministic in large scale as
>>well, but last time I checked, there was no way to distinguish
>>Copenhagen and Many Worlds.
>
> You and I both know that this "many worlds" hypothesis is just a feeble
>attempt to escape from the unforgiving determinism of spacetime.
You may know that. I do not. I understood it as an attempt to escape
from the unforgiving nondeterminism of the Copenhagen interpretation.
Many, many physicists would be far happier with a purely newtonian
universe, where all events followed precisely from thier causes, and
there was not a single random factor in it. While most are not that
fervent, both Einstein and Wheeler were very unhappy at the idea that
fundemental processes were not deterministic. (I am less certain about
Wheeler. Anyone have any biographical information?)
>How are
>these "many worlds" mapped onto spacetime, one might ask?
By the accounts I have read, each represents a branch, and each branch
sees a completely consistent spacetime continuum. As one goes forward,
there are more, and back, there are less, but there is no way for someone
in one of these worlds to ever see one of the others. I do not believe
Wheeler saw any need to distinguish between a finite number of branches
and an infinite number.
> And how does
>one jump from one to the other?
You do not. As soon as a wave function collapses, you get one world for
each possible outcome. As to how thistakes place, Wheeler did not state,
and it may not be possible to without some way of existing in the
hyperrealm which this is imbedded in.
>At what point in spacetime?
Well, every point, since spacetime is duplicated with only that decision
different in the past of anyone who is after that decision took place.
(Times given from the perspective of someone living in the splitting
universe.)
>If the
>picture is becoming very complicated very fast, it's because it is. IMO,
>the "only-now-exists" hypothesis is orders of magnitude simpler and thus
>it is much more in keeping with the spirit of Occam's razor.
I find the many worlds - branch on all decisions hypothesis about as
simple, given that you do need something as complicated as QM to explain
QM results. Your "only now exists" hypothesis woulkd get complicated
quickly if one added explanation for QM results, since I suspect you
would end up with something like Copenhagen. Perhaps not, though.
> I have no problem with a reality that requires partial determinism and
>partial uncertainty. Such a reality makes logical sense to me. The
>complementarity (the oneness, if you will) of determinism/uncertainty
>cannot be denied. Both are needed. One without the other is like 'up'
>without 'down'. I've mentioned this before but it bears repeating.
While that may be the case, I do not know that both are needed. I
suspect that though the philosophical definitions of determinism and
uncertainty are both needed, the actuality of both are not. In a
context of one person with a time coordinate, yes, but in the context
of a being completely outside the universe we perceive? I have no
data, and any guessing is just idle amusement.
Hmmm. Looks like I did not keep it terribly brief.
SavainL
schm...@fermi.wias-berlin.de (Ilja Schmelzer) writes:
>In article <4lkap6$5...@newsbf02.news.aol.com> sav...@aol.com (SavainL)
>writes:
>
>[...]
>>If GR proponents are saying that things act *as if* there were
>>spacetime curvature, I would say "HURRAY! I ACCEPT IT! I will accept
>>spacetime curvature as a mapping of events and no more. At least
>>until a more fundamental cause-and-effect theory is found". I HAVE NO
>>PROBLEM WITH THAT!
>>But you are the *only* one saying that, Jan.
>
>Not the only one, me too :-).
Great! I'm happy to hear it.
>>Everyone else is
>>ascribing a separate reality to spacetime. And I have a problem with
>>that.
>
>With "reality"? I think, the events (thus spacetime) are real too.
>I don't think it is "really bending".
The events are real alright but SR and GR's spacetime is a but mapping.
It does not exists out there. Everyone's been telling me (except you and
Jan Bielawski) that it's an actual, existent, physical structure. I've
refused to believe it and I will not believe it until I see empirical
evidence.
>>This whole discussion started when I asked "what is the cause of
>>motion?" John Baez said it was this living thing out there called
>>"spacetime metric" and that's where Einstein's genius came in. He
>>teaches a course in GR for God's sake! Doug Meritt came out and said
>>essentially the same thing. And that's exactly what I've been hearing
>>and reading about all along. Why could *not* John Baez and all the
>>books I've been reading say the same thing that you're saying? Why
>>did you *not* correct him when he posted his stuff?
>
>Because he is not really wrong. I cannot prove that the spacetime is
>not "really curved", as much as he cannot prove that the spacetime is
>"really curved".
Say what? I thought physics was an empirical science. If you cannot
prove something, why insist on talking about it as if it were true?
>If somebody is posting stuff saying nonsense in this direction, I
>usually reply, if I read it.
>
>> Why attack me when I'm objecting to it because it does not make
>>sense?
>
>If you say "it does not make sense" you are wrong.
>
>>Why has it taking this long for someone to come out and say what I've
>>been saying all along? You are the physicists. I'm supposed to take
>>your word and you are all saying different things. Why the
>>confusion??
>
>This is because there are established things - the experimental
>predictions - and a lot of stuff around which is not certain -
>interpretation.
Ahuh? Here's what John Baez said:
>Well, briefly put, the spacetime metric is the thing that lets us
>measure angles, distances, and the passage of time. It should not be
>surprising that we need to be able to measure angles, distances, and
>the passage of time in order to be able to tell if something is
>accelerating, and how much. What took smarts on Einstein's part was to
>think of this metric as a kind of "field" analogous to the
>electromagnetic field, and to think of it as *causing* the inertial
>motion of particles to be what it is, and thus to conceive of the
>possibility that it is interacting with them and thus must be affected
>by them.
>
>In other words, before Einstein the metric seemed like a very abstract
>thing, a matter of mere "geometry" rather than physics. Einstein
>realized it was a living, pulsing, physical field just like
>electromagnetism. He realized that in this case, geometry was really
>physics. These days people might say: physics was really geometry!
Does this sound like a mere interpretation to you? Does it not clearly
show that Baez thinks that the "spacetime metric" is a real physical
structure that's *directly causing* things to happen? I could be wrong.
So please correct me.
>Unfortunately it is hard to explain something to laymen without using
>one of the possible interpretations.
You know, I don't know if you realize this, but this is an deceitful,
insulting, and condescending thing to say to others. Why not simply tell
the truth? If the truth is that spacetime is but a mapping of events, I
don't see what's so hard to understand. I'm a layperson and I don't have
any trouble understanding it. It is the deceitful intepretations that are
making things hard to understand. Not the truth.
What's this "interpretation" business anyway? Things are what they are
or they are not. If you don't really know the meaning of something, have
the courage to come right out and say it. Don't interpret, and if you do
have to interpret (speculate?) to make a point, just forewarn the reader
that you are indeed doing so. Is this religion or science?
>Many scientists have simply not recognized that there may be other
>interpretations are possible in GR and explain only the standard
>interpretation from Einstein. In quantum mechanics the situation is
>better - people usually say clearly which things depend on the
>interpretation.
Well, this seems to be a lesson that spacetime physicists sorely need to
learn. They are not making converts out there with their interpretations.
What I mostly see from them is arrogant condescension.
>In my own interpretation of GR the tensor field g_ij describes the
>ether, which is not stationary but interacts with material fields.
>The influence material -> ether -> other material is gravity. There is
>an absolute time and an absolute space. (Exactly speaking, this is not
>GR itself, but a slightly different theory which I have named
>post-relativistic gravity, but the experimental predictions are
>de-facto the same.)
Thanks for warning us that it's *your interpretation*.
>> Please come out and tell me, all of you, that you do not ascribe a
>>***cause and effect reality*** to spacetime and I will definitely
>>accept it and study it further. Heck I'll apologize to everybody and
>>I'll study the math too. But as John Baez explained it it does not
>>make sense.
>
>Sorry, cause and effect are connected with spacetime. At least in the
>following sense: There is some event which may have a causal influence
>on some other event. We can do now a lot of measurements using clocks,
>light and so on, and based on these measurements we can decide if such
>a causal connection is possible.
I don't have a problem with that. There is *indirect* causation. The
*spacetime mapping* simply shows how the cause (event 1) is indirectly
connected to the effect (event 2). That's fine. But I refuse to accept
the notion that's being bandied about by many that somehow there's a
direct cause and effect connection between the *mapping itself* and the
events. When the actual intermediate causal mechanism (quantum gravity?)
is finally found, then its predictions can be compared with reality and
with the predictions of GR to determine its accuracy.
>We don't know what we really measure with our clocks, we don't know
>why this is true, we don't know if it remains true in the quantum
>theory. But nonetheless "spacetime" - the mapping of events with their
>distances measured by clocks - is connected with cause and effect.
Thanks for admitting that "We don't know what we really measure with our
clocks". I agree with the above.
>John Baez explanations make sense. It is simply another interpretation
>of the same theory.
He should have come right out and forewarned all readers, especially
layfolks, that he was simply "interpreting". He did not do so. He was
speaking like Moses, freshly down from the presence of Yahweh carrying the
tablets of the law. And his interpretation still does not make sense
because he was ascribing an independent existence and a direct causal
property to spacetime. And we all know, by now that spacetime is but a
mapping of events!!! Why do you insist on defending something that makes
no sense? This looks, to us laypeople, like a thinly veiled collusion
within a good old boy network. Sorry. But if I'm wrong, please don't
hesitate to correct me.
SavainL
Rams...@hermes.bc.edu (Keith Ramsay) writes:
At this point I don't think I want to discuss this anymore. I've been
told by 2 physicists (I think they are both physicists) that the spacetime
of relativity is but a mapping of events, something I've been saying all
along. All the other stuff about an actual existent spacetime *directly
causing* things to move are just private interpretations. Apparently you
didn't get the news. Sorry.
LBsys
> At this point I don't think I want to discuss this anymore.
So you set the rules in this universe, right? After having told the world
that physicists like JB, Meron and van Esch, to name only a very few, are
completely nuts, and your deep insight into physics is the right one, you
just start hiding. Louis, as long as you can't tell a definition from an
equation, not mathematically, but simply logically, you better skip the
whole issue. Write a pilosophical treatise about cause and effect, but
stay away from physics.
>I've been
>told by 2 physicists (I think they are both physicists) that the
spacetime
>of relativity is but a mapping of events, something I've been saying all
>along. All the other stuff about an actual existent spacetime *directly
>causing* things to move are just private interpretations.
You have painstakingly picked up only the opinion of those, who, for one
obvious reason or the other, 'supported' your infight with the
heavyweights. Why don't you go and become a scholar to VV? Or AA? You are
far too intelligent not to know exactly what I mean. And if you really
have to take this (far too..) as a compliment, I have to remind you, that
'til to this day you were not able to answer my last post in the "Inertial
motion" thread. The one where I layed out, that even on easy subjects
(force and acceleration) you mix up things and, wondersome, get wrong
results. Someone else commented (privately) on this:
>>>>>
Excellent explanation of what f = ma really means (whether it did any
good, I
don't know but, hey, you did your best). It is amazing how many people
fall
into the trap of reading the equation as "we assign the name ""force"" to
the
product of mass and acceleration". If that would be the meaning then it
would've been just a definition, a naming convention, thus devoid of any
real
significance.
It is important, and often overlooked, to realize the difference between
an
equation and an identity. An identity is a statement which is always
true. An
equation is a statement which is almost always false and that's why the
case
(or cases) for which it is true are of special significance. f = ma is an
equation.
<<<<<<
And someone else on the same subject:
>>>>
Yes, I've seen your response, and indeed the poor guy is missing
the point of F = m.a completely, but he got so rude I didn't really
want to continue the discussion any further (he's in my killfile
now). BTW, I think - but I don't know GR enough - but I think
JB screwed up masterly with his dispersion of light :-)
<<<<
So what do you make out of this: first, yes, there are others, who think
that this 'Master of (Sci)Physics' once in a while makes a mistake or two
on minor facts. Secondly, even *if*, it's always taken into account, that
oneself might not have ones own fact right. And third: you were way off
track with your thinking on the rather simple subject f=m*a. That being
the case, you probably should start your learning of physics all over
again, before you tell all the world how nuts them experts are on GR.
>Apparently you
>didn't get the news. Sorry.
With that sort of attitude, your halftime as a physicist will be less than
3 boiled eggs (as PvE would measure it).
David Smyth
>
> Gosh! That's exactly the point I've been making all over the place,
>spacetime curvature, I would say "HURRAY! I ACCEPT IT! I will accept
>spacetime curvature as a mapping of events and no more. At least until a
>more fundamental cause-and-effect theory is found". I HAVE NO PROBLEM
>WITH THAT!
>ascribing a separate reality to spacetime. And I have a problem with
>motion?" John Baez said it was this living thing out there called
>"spacetime metric" and that's where Einstein's genius came in. He teaches
>a course in GR for God's sake! Doug Meritt came out and said essentially
>the same thing. And that's exactly what I've been hearing and reading
>about all along. Why could *not* John Baez and all the books I've been
>reading say the same thing that you're saying? Why did you *not* correct
>because it does not make sense?
I think the thing you fail to understand is that spacetime is as real as
anything can be. Try to name anything which you believe is "more real"
than spacetime.
The trouble with using phrases like "separate reality" is nobody knows what
this means. The correct scientific procedure would be to give the phrase
"separate reality" a definition which can be related to scientific
observation. Then demonstrate (through observation) that spacetime does
not satisfy this definition. You should then demonstrate that other
phenomena (such as light which I assume you think is somehow "more real"
than spacetime) does satisfy your definition.
The question you're asking is more than likely a philosophical one and
therefore outside the realm of fundamental physics and has no bearing
whatsoever on the validity of GR as a scientific theory.
I think you're trying to understand GR without first understanding what
science is all about. At least you're not trying to rewrite physics
without first understanding what science is all about (unlike one other
well known sci.physics identity).
David Smyth
CPL
University of Queensland
SavainL
writes:
>sav...@aol.com (SavainL) schreibt:
>
>[insults deleted]
>
>I have to remind you, that
>'til to this day you were not able to answer my last post in the
>"Inertial motion" thread. The one where I layed out, that even on easy
>subjects (force and acceleration) you mix up things and, wondersome,
>get wrong results.
If you're referring to your "apples and pears" explanation of 'f = ma',
I did answer and you failed to respond.
> Someone else commented (privately) on this:
>
>>>>>>
>Excellent explanation of what f = ma really means (whether it did any
>good, I don't know but, hey, you did your best). It is amazing how
>many people fall into the trap of reading the equation as "we assign
>the name ""force"" to the product of mass and acceleration". If that
>would be the meaning then it would've been just a definition, a naming
>convention, thus devoid of any real significance.
>
>It is important, and often overlooked, to realize the difference
>between an equation and an identity. An identity is a statement which
>is always true. An equation is a statement which is almost always
>false and that's why the case (or cases) for which it is true are of
>special significance. f = ma is an equation.
><<<<<<
Would you be so kind as to clearly point out the cases in physics where
'f = ma' is false? BTW, this is one area where I thought that Baez'
thought experiment was touching upon some real problems in physics
regarding cause and effect. Apparently, judging from the deleted insults,
"cause and effect" is just so much "philosophy" to you. Why don't you
just eliminate them altogether from all your thinking?
>And someone else on the same subject:
>
>>>>>
>Yes, I've seen your response, and indeed the poor guy is missing
>the point of F = m.a completely, but he got so rude I didn't really
>want to continue the discussion any further (he's in my killfile
>now). BTW, I think - but I don't know GR enough - but I think
>JB screwed up masterly with his dispersion of light :-)
><<<<
I don't remember getting rude to you ever. Why the insults and why do
you post this as if it were true? Is this some exercise in disingenuity?
>So what do you make out of this: first, yes, there are others, who
>think that this 'Master of (Sci)Physics' once in a while makes a
>mistake or two on minor facts. Secondly, even *if*, it's always taken
>into account, that oneself might not have ones own fact right.
What got me angry WRT Baez is that he tried to cover up a silly mistake.
This shows that peer approval and "marketing" is much more important in
physics than truth. This kind of stuff hurts me because it destroys the
original (however naive) trust that one had in one's teachers. I've made
mistakes before on this forum and when Mati Meron corrected me, I
immediately thanked him for setting me straight. It's not all that hard.
> And
>third: you were way off track with your thinking on the rather simple
>subject f=m*a. That being the case, you probably should start your
>learning of physics all over again, before you tell all the world how
>nuts them experts are on GR.
Several physicists came out and in all seriousness wrote some of the
dumbest things I've ever read. When I first politely pointed out the
problem in what they said, taking pains to indicate that they should
correct me if my understanding of their message was wrong, they declined
to respond. So I take it to be either a sign of stupidity or dishonesty
on their part. If you want to take sides, Lorenz, by all means, do so.
That's what I call herd mentality. My own mentality is to seek the truth.
I don't side whith anyone, even those with whom I agree at times.
Apparently, your post is intented as a punitive vendetta because I failed
to agree with your "apples and pears" interpretation (everybody is
interpreting this days, I feel like I'm in church) of 'f = ma'. I refuse
to belong to your herd or anyone else's herd afor that matter. Count me
out.
>[More punitive insults deleted]
SavainL
writes:
>I'll keep this short. After all, both of us have said that we saw
>little need to continue.
I read it and apparently you put a lot of thought into it.
>In article <4ljkus$o...@newsbf02.news.aol.com>, SavainL<sav...@aol.com>
>wrote:
>>[...]
>> One of the biggest conceptual problems with a predeterminded,
>>motionless spacetime is that there is no way to determine by "looking"
>>at it, *where* the present is. The present seems to reside everywhere
>>along the time dimension. What mechanism does the theory provide to
>>make such an important observation? In other words, what
>>differentiates the future from the past? What is the meaning of 'now'
>>in spacetime? I strongly suspect spacetime provides no answers to
>>these questions.
>
>But there is an implicit "now" in the structure of spacetime, from the
>view of anything imbedded in it. To them, the t coordinate is thier
>"now." That it is difficult to have two people agree on what "now" is
>given differing velocities and accelerations merely means that the
>present is not easy to define. Newton thought it was. Hawking does
>not.
Point well taken. The "now" of relativity is indeed relative. That
does not mean that at a deeper level there isn't a true now. I believe
that in the future the true 'now' will be inferred from our observations.
I'm not so sure about the "implicit" stuff though.
>Now if you mean that, from the point of view of someone outside
>spacetime, there is no way to select a given point along the t axis as
>the present, I suspect you are quite right. I would be terribly
>surprised if any time coordinate in spacetime mattered from that
>perspective.
Oh, it does. Any structure or theory dealing with time as an existent
dimension, that does not provide a mechanism for spotting the 'now' on
this dimension, is terribly lacking in explanatory power.
>> A more plausible alternative is that only the 'now' exists. The
>>question then becomes, "what is meant by the 'now' or 'present'?" If
>>physicists could provide a logical answer to this question, then I
>>would be really impressed.
>Well, it depends on just what you want out of your present. Do you
>want one that makes sense to you, or to an observer independent of
>time? (By the way, I got into this argument with a priest over free
>will, determinism, and predestination when I was eight or nine, so I do
>not think that physics alone has tackled the problem. Physics merely
>has a very precise vocabulary (mathematics) and a final appeal to
>experiment as fundemental tools. Other ways of inquiry use different
>techniques, and come to different answers. To the best of my
>knowledge, physics rarely attempts to answer questions about a
>hyperrealm in which some kind of meta time takes place, and satisfies
>itself with exploring the universe we can measure.
If "physics" only dealt with observations I failed to see the utility of
"spacetime". Only the 'now' can be observed.
>I am going to indulge, and wax philosophical for a moment. From one
>point of view, the entire universe could be considered a single object,
>including the past, present, and future.
It's a point of view that I've seen many times before and that many
"spacetime" physicists seem to dearly hold on to even though there is no
empirical evidence for it.
> To a being living inside it,
>it is a dynamic thing, since as time passes, things change, but to a
>being outside it, it is as dynamic as a pencil line drawn on paper.
>Part of am aesthetically pleasing picture, one hopes, but a finished
>work.
That's where, I think, the point of view pitifully breaks down because
"as time passes" raises a powerful and bothersome circularity.
That's why I prefer to think that motion has primary existence and the
notion of time emerges from that.
>I, too, would be impressed by any understanding of the matrix in which
>the universe exists. I am not holding my breath, though, because it
>seems likely that there are singularities between us and any outside
>realm.
Sorry I'm not sure what you mean by "there are singularities between us
and any outside realm."
>>>[...]
>>
>> You and I both know that this "many worlds" hypothesis is just a
>>feeble attempt to escape from the unforgiving determinism of
>>spacetime.
>
>You may know that. I do not. I understood it as an attempt to escape
>from the unforgiving nondeterminism of the Copenhagen interpretation.
Interesting slant. Thanks for bringing it up. I too would object to
the Copenhagen interpretation if it postulated 100% uncertainty or
randomness. Does it really do that. I can't see how anything can exist
with such a view.
>Many, many physicists would be far happier with a purely newtonian
>universe, where all events followed precisely from thier causes, and
>there was not a single random factor in it.
That's a strange thing to say. What does "happy" have to do with it?
Physicists should not have firm preconceived notions. All notions
(assumptions) should be tentative until supported by evidence. No?
>>>[...]
>>How are
>>these "many worlds" mapped onto spacetime, one might ask?
>
>By the accounts I have read, each represents a branch, and each branch
>sees a completely consistent spacetime continuum. As one goes forward,
>there are more, and back, there are less, but there is no way for
>someone in one of these worlds to ever see one of the others. I do not
>believe Wheeler saw any need to distinguish between a finite number of
>branches and an infinite number.
>
>> And how does
>>one jump from one to the other?
>
>You do not. As soon as a wave function collapses, you get one world
>for each possible outcome. As to how thistakes place, Wheeler did not
>state, and it may not be possible to without some way of existing in
>the hyperrealm which this is imbedded in.
>
>>At what point in spacetime?
>
>Well, every point, since spacetime is duplicated with only that
>decision different in the past of anyone who is after that decision
>took place. (Times given from the perspective of someone living in the
>splitting universe.)
You will forgive me but all this sounds like it should be relegated to
the domain of science fiction, not science. I've read about all of it
before. I really think that for someone of Wheeler's stature, making such
wild speculations about reality without any evidence to back it up is an
obscene abuse of one's academic reputation. If this stuff had come from a
layperson he or she would have immediately been branded as a crackpot.
>>If the
>>picture is becoming very complicated very fast, it's because it is.
>IMO, the "only-now-exists" hypothesis is orders of magnitude simpler
>and thus it is much more in keeping with the spirit of Occam's razor.
>
>I find the many worlds - branch on all decisions hypothesis about as
>simple, given that you do need something as complicated as QM to
>explain QM results. Your "only now exists" hypothesis woulkd get
>complicated quickly if one added explanation for QM results, since I
>suspect you would end up with something like Copenhagen. Perhaps not,
>though.
I would think the latter. Besides, it's obvious that QM is not the
end-all of physics. Otherwise physicists would have stopped searching.
>> I have no problem with a reality that requires partial determinism
>and partial uncertainty. Such a reality makes logical sense to me.
>The complementarity (the oneness, if you will) of
>determinism/uncertainty cannot be denied. Both are needed. One
>without the other is like 'up' without 'down'. I've mentioned this
>before but it bears repeating.
>
>While that may be the case, I do not know that both are needed. I
>suspect that though the philosophical definitions of determinism and
>uncertainty are both needed, the actuality of both are not. In a
>context of one person with a time coordinate, yes, but in the context
>of a being completely outside the universe we perceive? I have no
>data, and any guessing is just idle amusement.
Interesting comment. One which may well be hard to argue against but
I'll try. IMO, we cannot understand complementary concepts (like up/down,
certainty/randomness) unless we see or are aware of examples of both. We
distinguish one by contrasting it to the other. Complementary phenomena
are *one* and cannot be separated. If only one existed we would not be
able to make it out for what it is. The minute you think of one,
immediate the other exists. I believe it's also a teaching of Tao. But I
also think that it may well be something that cannot be conclusively
demonstrated to anyone. I don't know. I hope I'm wrong.
>Hmmm. Looks like I did not keep it terribly brief.
It's a challenging post and I appreciate it.
SavainL
>[vengeful insults deleted]
And then dav...@psych.psy.uq.edu.au (David Smyth) wrote:
>[more vengeful insults deleted]
Gosh! My reputation is ruined! I'm the laughing stock of sci.physics!
What am I going to do? My life is forever in shambles! You guys sure get
easily offended by crackpots like me. I wonder why. Insecurity maybe?
Paranoia? This brings to mind a famous saying: "Many shall take offense
and woe to those from whom the offense come". I'm trembling.
Edward Green
>At this point I don't think I want to discuss this anymore. I've been
>of relativity is but a mapping of events, something I've been saying all
>along. All the other stuff about an actual existent spacetime *directly
>causing* things to move are just private interpretations. Apparently you
>didn't get the news. Sorry.
Hi Louis
May I interject a note of levity? I happen to be reading a book about
Navy seals in Vietnam. They infiltrated deep behind enemy territory, and
then extracted. Sometimes, they got themselves in "a world of shit".
That means they took heavy fire, were surrounded, badly outnumbered,
etc.
It seems to me that your infiltration mission deep into physicist held
territory has gotten you into a world of shit. At first the natives seemed
friendly. You bartered with them for intelligence. Then, something went
wrong. You were drawn into a heavy epistemological firefight. You are
surrounded and taking heavy fire. Better call for air support. Then make
a tactical retreat.
--
Ed Green / egr...@nyc.pipeline.com
Occam used a double-edged razor.
SavainL
In article <4lovod$4...@pipe8.nyc.pipeline.com>, egr...@nyc.pipeline.com
(Edward Green) writes:
>[...]
>Hi Louis
>
>May I interject a note of levity? I happen to be reading a book about
>Navy seals in Vietnam. They infiltrated deep behind enemy territory,
>and then extracted. Sometimes, they got themselves in "a world of
>shit". That means they took heavy fire, were surrounded, badly
>outnumbered, etc.
>
>It seems to me that your infiltration mission deep into physicist held
>territory has gotten you into a world of shit. At first the natives
>seemed friendly. You bartered with them for intelligence. Then,
>something went wrong. You were drawn into a heavy epistemological
>firefight. You are surrounded and taking heavy fire. Better call for
>air support. Then make a tactical retreat.
Hi Ed
I fell on the floor rolling with laughter when I read this. You're
right. The battle will never be won by engaging in minor skirmishes in
the usenet jungle. The air support is nowhere in sight. Sound the
retreat at once! The rebel forces are taking a licking. They must
embrace a common cause to boost their morale and then organize under a
decisive new leader. Any volunteers?
PS. The war is far from over. It may flare up unexpectedly in the least
suspected places. :-)
Mikko Levanto
> >With "reality"? I think, the events (thus spacetime) are real too.
> >I don't think it is "really bending".
>
> The events are real alright but SR and GR's spacetime is a but
> mapping. It does not exists out there. Everyone's been telling me
> (except you and Jan Bielawski) that it's an actual, existent,
> physical structure. I've refused to believe it and I will not
> believe it until I see empirical evidence.
I don't think it is correct to call spacetime a mapping. It is
those events and the individual and collective properties of those
events. If the events exist, so does the spacetime, otherwise not.
> Say what? I thought physics was an empirical science. If you
> cannot prove something, why insist on talking about it as if it were
> true?
Sometimes that may make it easier to talk about something that
can be proven, at least to those who already know the style.
So why not? Non-reality of nature is unprovable, at least with our
present skills, so why to mention it?
> >In other words, before Einstein the metric seemed like a very abstract
> >thing, a matter of mere "geometry" rather than physics. Einstein
> >realized it was a living, pulsing, physical field just like
> >electromagnetism. He realized that in this case, geometry was really
> >physics. These days people might say: physics was really geometry!
>
> Does this sound like a mere interpretation to you? Does it not
More like poetry.
> clearly show that Baez thinks that the "spacetime metric" is a real
Not clearly, only opinions of others (Einstein, people [of these days])
are presented, probably because they are considered worth of
consideration.
> physical structure that's *directly causing* things to happen? I
> could be wrong. So please correct me.
Does it make sense to assume that there is (always or sometimes) some
direct cause that makes a thing to happen? If yes, then it also
makes sense to assume a physical structure for that cause. A
postulated structure can be called "spacetime metric" if it has
most of the properties that one would expect from a metric in a
mathematical theory.
> >Unfortunately it is hard to explain something to laymen without using
> >one of the possible interpretations.
>
> You know, I don't know if you realize this, but this is an deceitful,
> insulting, and condescending thing to say to others. Why not simply
> tell the truth?
It may be deceitful, insulting, and condescending, but I think it
is the truth.
> If the truth is that spacetime is but a mapping of events, I
> don't see what's so hard to understand.
If the spacetime were a mapping, one would have to ask, a mapping
from what to what. Otherwise one can't understand anything about
a mapping. But I don't think it is.
> I'm a layperson and I don't have any trouble understanding it.
Maybe it is something that only a layperson can understand.
BTW, what exactly do you mean by that word? I've often heard
laypersons to use that word and wondered what they mean.
> >In my own interpretation of GR the tensor field g_ij describes the
> >ether, which is not stationary but interacts with material fields.
> >The influence material -> ether -> other material is gravity. There is
> >an absolute time and an absolute space. (Exactly speaking, this is not
> >GR itself, but a slightly different theory which I have named
> >post-relativistic gravity, but the experimental predictions are
> >de-facto the same.)
>
> Thanks for warning us that it's *your interpretation*.
Don't miss the second warning that it is, exactly speaking,
not an interpretation of GR.
> >Sorry, cause and effect are connected with spacetime. At least in the
> >following sense: There is some event which may have a causal influence
> >on some other event. We can do now a lot of measurements using clocks,
> >light and so on, and based on these measurements we can decide if such
> >a causal connection is possible.
>
> I don't have a problem with that. There is *indirect* causation.
> The *spacetime mapping* simply shows how the cause (event 1) is
> indirectly connected to the effect (event 2). That's fine. But I
> refuse to accept the notion that's being bandied about by many that
> somehow there's a direct cause and effect connection between the
> *mapping itself* and the events.
Unless you accept that there is some physical mechanism between
the two events (cause and effect), you should not call it "indirect".
> When the actual intermediate causal
> mechanism (quantum gravity?) is finally found, then its predictions
> can be compared with reality and with the predictions of GR to
> determine its accuracy.
In the mean time the predictions of GR can already be compared
with reality.
> >John Baez explanations make sense. It is simply another interpretation
> >of the same theory.
>
> He should have come right out and forewarned all readers, especially
> layfolks, that he was simply "interpreting". He did not do so.
Do you always warn that everything you say is an interpretation?
-----------------------------------------------------------------
Mikko J. Levanto Tel. +358 81 551 2448
VTT Electronics Fax +358 81 551 2320
P.O.Box 1100 (valid until 1996-10-12)
FIN-90571 Oulu, Finland Internet: Mikko....@vtt.fi
--------------- VTT - Technical Research Centre of Finland ------
Edward Green
'sav...@aol.com (SavainL)' wrote:
>lb...@aol.com (Lbsys) writes:
>
>>Excellent explanation of what f = ma really means (whether it did any
>>good, I don't know but, hey, you did your best). It is amazing how
>>many people fall into the trap of reading the equation as "we assign
>>the name ""force"" to the product of mass and acceleration". If that
>>would be the meaning then it would've been just a definition, a naming
>>convention, thus devoid of any real significance.
the nth time (but maybe I will pass on the n + 1 :-) ...
The content of this equation is that it turns out to be useful to abstract
these quantities (force and mass; length and time being regarded as
already abstracted from experience) from many interactions -- "useful"
because we can assign a number "f" to some interaction, and a number "m"
to some body, such that when we play mix and match with the interactions
and the bodies, we get the right acceleration.
If we want to take the "mass" as a primitive, accepting its identification
with gravitational mass, then the content is that it is possible to
abstract a number "f".
So when someone begins to wonder "but what is a force, *really*?", and
decides that somehow the whole thing is a matter of definition, he is half
right... or rather, he has moved from one wrong view, that the "force" is
a pre-existing something, independent of this realtion, to another wrong
view, that the force is tautologically *defined* by this relation.
It turns out to be a useful definition, because we can abstract the force
and apply it to different masses, which may not have been possible. The
world could have worked otherwise.
Sometimes I think Newton got a bum rap vis-a-vis gravitation in this light,
he was supposed to have postulated a fictitious action-at-a-distance
"force", which we dispose of in GR... but this "force" is already a
powerful abstraction.
LBsys
Im Artikel <4lol62$f...@newsbf02.news.aol.com>, sav...@aol.com (SavainL)
schreibt:
>If you're referring to your "apples and pears" explanation of 'f = ma',
>I did answer and you failed to respond.
No, Louis, I'm not refferring to this. I gave it another try, which you
might have overlooked. This is, what the other quotes (excellent
explanation...) referred to. It was about the difference of a definition
and an equation. You seems to take f=m*a as a definition. Thus you
concluded, if there is force, there has to be motion, as it resides in the
definition. Thus you got JB's argument about the bum leaning against the
wall completely wrong. I would have to go back in the thread online to
cite it here, b/c I'm keeping track only a few days back on my HD. I'm not
going to do this, as obviously other ones read it, so it's your turn. To
give you a clear hint: I mentioned an F16 jet at full thrust pressing
against a big spring. At one side of the system there is movement and
acceleration (of air molecules), on the other side, there is sheer force
resisting that and no motion.....
>>>>> [I cited *someone* else ... ]
>>An identity is a statement which
>>is always true. An equation is a statement which is almost always
>>false and that's why the case (or cases) for which it is true are of
>>special significance. f = ma is an equation.
>><<<<<<
>Would you be so kind as to clearly point out the cases in physics where
>'f = ma' is false?
No, b/c that was not what the quote says. The singular used above stands
for 'all', thus the statement reads that from the quantity of all possible
equations, most are false and if we find one, that holds true, we should
have a good look, as 'it is of special significance'. Would you care to do
a little thinking and not always conclude first hand that all other people
are plain stupid?
>BTW, this is one area where I thought that Baez'
>thought experiment was touching upon some real problems in physics
>regarding cause and effect. Apparently, judging from the deleted
insults,
>"cause and effect" is just so much "philosophy" to you. Why don't you
>just eliminate them altogether from all your thinking?
I don't. I just thought, that it might help you if you first hand dive
deeper into that tricky cause/effect question. Quite often, the effect is
hidden. If we then conclude, that there has been no cause, or, if we see a
cause and cannot see the effect instantaneously, that something with our
system must be wrong, we are shortsighted.
>>>>>
>Yes, I've seen your response, and indeed the poor guy is missing
>the point of F = m.a completely, but he got so rude I didn't really
>want to continue the discussion any further (he's in my killfile
>now). ....
<<<<<<
>I don't remember getting rude to you ever.
True, and I didn't claim that. I was clearly citing someone. It was that
someone you have been insulting in the past.
>Why the insults and why do you post this as if it were true?
Why the insults? Ask yourself, you were the one insulting others!
Why do I post it as if it were true? B/c it is true - everyone could read
it. You post your insults publically. Then you claim they were uncalled
for and apologize. Then you wait 24 hours. Then you decide, you should
have had some TLC by that time. As there wasn't any, you decide: more
insults needed. Have you ever read Watzlawicks little book "How to make
yourself unhappy?" (I don't know if that's the real title, in German it's
'Anleitung zum Ungluecklichsein'). It concludes in the statement, that
people who engage in unsuccessful strategies tend not to change it, but
instead choose: More of this!
>What got me angry WRT Baez is that he tried to cover up a silly mistake.
>This shows that peer approval and "marketing" is much more important in
>physics than truth. This kind of stuff hurts me because it destroys the
>original (however naive) trust that one had in one's teachers. I've made
>mistakes before on this forum and when Mati Meron corrected me, I
>immediately thanked him for setting me straight. It's not all that hard.
First of all: growing up is hurting anyone. You have to learn that the
world is imperfect. Teachers aren't always right, and sometimes they don't
even like to admit it. The sooner you learn the better.
Secondly: Are you really sure, that JB has a problem to admit mistakes? I
saw it once happen, and he showed no problem (the 'gravitational rainbow':
he freely admitted, that he thought to have read it in a book, and when he
looked it up, it wasn't there. That happens, our brain is *not* perfect.
Sometimes you are so damn sure, you have read this or that, and when you
look it up, it's not there).
Thirdly: Yes, marketing in our world is a very important factor.
Unfortunately. It ever has been true, that the Mac-OS was years ahead of
DOS or anything Bill Gates has ever copied. Now who made the biz? Same
thing goes for PC's: at the time of the invention of the micro channel,
IBM PC's were way behind others. Big companies still bought the slower,
but dearer IBMs. But: the 'truth' can't be hold back forever. Marketing
doesn't hold forever. Truth emerges like the little flower that's breaking
through the asphalt of the street. It may take some time though :-)
>If you want to take sides, Lorenz, by all means, do so.
>That's what I call herd mentality. My own mentality is to seek the
truth.
I'm not taking sides. I have my own head. I'm uncertain of my findings, so
I'm happy if others agree. That doesn't mean, I'll agree on every single
one of their thoughts. And in this case, I don't agree with you. That's
all.
>I don't side whith anyone, even those with whom I agree at times.
>Apparently, your post is intented as a punitive vendetta because I failed
>to agree with your "apples and pears" interpretation (everybody is
>interpreting this days, I feel like I'm in church)....
Now isn't that an interpretation of some sort? And based on false
assumptions? As I said: it wasn't about apples and pears, so it wasn't a
punitive vendetta. How did you came to that conclusion?
Bad case of misinterpreting the cause of an ill observed effect????
Make out of it, whatever you want. I have learned a lot while reading
sci.physics. Not about the people (I'm too old to be told about people),
but on the matter. Did you learn something?
Keith Ramsay
In article <qmsDqD...@netcom.com>, q...@netcom.com (Scott Ellsworth) wrote:
|You do not. As soon as a wave function collapses, you get one world for
|each possible outcome. As to how thistakes place, Wheeler did not state,
|and it may not be possible to without some way of existing in the
|hyperrealm which this is imbedded in.
Rather, the wave function does not collapse, and the various bits of it
individually resemble "worlds", by a metaphor well worth being careful
about.
Keith Ramsay
me...@cars3.uchicago.edu
In article <4lp5vf$g...@pipe8.nyc.pipeline.com>, egr...@nyc.pipeline.com (Edward Green) writes:
>'sav...@aol.com (SavainL)' wrote:
>
>>lb...@aol.com (Lbsys) writes:
>>
>>>good, I don't know but, hey, you did your best). It is amazing how
>>>many people fall into the trap of reading the equation as "we assign
>>>the name ""force"" to the product of mass and acceleration". If that
>>>would be the meaning then it would've been just a definition, a naming
>>>convention, thus devoid of any real significance.
>
>the nth time (but maybe I will pass on the n + 1 :-) ...
>
>The content of this equation is that it turns out to be useful to abstract
>these quantities (force and mass; length and time being regarded as
>already abstracted from experience) from many interactions -- "useful"
>because we can assign a number "f" to some interaction, and a number "m"
>to some body, such that when we play mix and match with the interactions
>and the bodies, we get the right acceleration.
>
The content starts with the fact that it is an equation, not identity
(else it would've been useless). It is tying together two completely
different quantities, the acceleration which is a property of the body
and the force which is identified with a source outside of the body.
A priory these quantities are independent. F = ma is stating that in
any physical interaction they must be proportional. Moreover the
coefficient in this proportion (i.e. the mass) is a property of the
body, independent of both theforce and the acceleration.
Would F = ma mean just "we hereby name the product of mass and
accleration a force" it would've been pretty much useless.
Since I'm already at this, I would like to correct an error that
appeared around here not long ago. Somebody stated that when a body
is acted on by few forces, only the total force has a physical meaning
and the individual ones are just "mental constructs". Not so. Since
each force is identifiable with an external source, each force has a
physical meaning. If a mass is hanging on a spring in a gravity
field, it is acted upon by the spring and by the force of gravity (I'm
in classical mechanics here so forget curvature for a moment). Each
of this two forces is known to us and each can be measured in the
absence of the other. They are real. What is true that if we assign
to each force a partial acceleration, like in
F = F1 + F2 = ma1 + ma2 = ma
then the partial accelerations, a1 and a2 are just mental constructs
and only the total acceleration ma has a physical meaning.
Mati Meron | "When you argue with a fool,
me...@cars.uchicago.edu | chances are he is doing just the same"
Edward Green
'me...@cars3.uchicago.edu' wrote:
>I'll put a slightly different slant on it (hope you don't object).
disagrees with me. I have never perceived anything but professional
courtesy from you, so I hope you will continue to put different slants on
things. I hope you will allow sometimes that in areas of my competence,
I may sometimes disagree.
(My, I *am* serious today ;-)
>The content starts with the fact that it is an equation, not identity
>(else it would've been useless). It is tying together two completely
>different quantities, the acceleration which is a property of the body
>and the force which is identified with a source outside of the body.
>A priory these quantities are independent. F = ma is stating that in
>any physical interaction they must be proportional. Moreover the
>coefficient in this proportion (i.e. the mass) is a property of the
>body, independent of both theforce and the acceleration.
certainly wasn't proposing that this is *merely* definition. It may be my
way is not the most useful way of looking at the content of this, but let
me try to explain it again. I hope you don't mind?
Suppose we can measure masses, time and distance without applying this
equation (we could measure mass with a balance beam, relative to a
reference mass, for example, ignoring for now the possible distinction
between gravitational and inertial mass). So we can also measure
acceleration, the only new feature of this equation being "force".
Now, let's bring test mass #1 up to bat and strap on a little standard
issue test rocket to it, which will serve as a *reproducible* force
(assume the rocket has negligible mass). So, we release the mass (in
intergalactic space, of course :-) and pffft! the little rocket fires
off, during which interval we record an average acceleration. Sooo....
let's "define" (give me a minute here) the "force" to be f_1 = (m_1)a_1.
So far, we haven't done anything except write one symbol for two. Ok?
Now, let's bring mass #2 up to the plate, and pffft! we calculate f_2 =
(m_2)a_2. Now (assuming our standard rockets have reasonable quality
control :-) we make a momentous discovery:
f_1 =~ f_2
Cosmic! Now we have some physics. We excitedly test this generalization
for many different masses, and find that.... f_i is distributed as a
Gausian random variable! (Ha... I bet you thought I was going to say they
were all equal :). Hmm... Maybe force is non-deterministic? Being bold
theorists though, we confidently assert: "The variation in f_i is do to
minute uncontrollable variations in manufacturing the rockets, in weighing
the masses, and measuring the trajectories. We therefore conjecture
that if we could meaurse the *real* physical quantities, we would always
have:
f = ma
Notice according to my development, we had no *preexisting* idea of "f".
So this is why I balk a bit at the idea of "tying together two completely
different quantities". According to this imagined development, we
started out by assigning a number to each interaction pretty much by
definition, and then noticed that if we kept *some* physical aspect
constant over these interations (keeping the little rockets as identical
in manufacture as possible) we can apply the the *same* number to all
these interactions, and predict the outcome. The physics is in the second
step. A priori, it could have turned out that (starting from pre-exsiting
concepts of mass and acceleration) we could only abstract a consistent
number by defining " f = (ma)^2 " or some more complicated relation.
Right?
Do you see my point? It's possible for an equation to *both* define a new
physical quantity *and* contain real physics, provided the definition is
stated in such a way that it *might* fail to be consistent -- as you say,
it's an equation, not an identity. Maybe we could call this the
"bootstrap" definition of physical properties; definition and physical law
rolled into one!
I'm sorry this was so long... but I wanted to try to clear this up.
On the other hand, if we regard "force" as having some pre-existing
operational definition *not* in terms of acceleration -- spring compression
or other material effect for example -- then we can avoid these
epistemological gymnastics, and just accept that this is an equation
relating otherwise independent quantities, as you say.
Do you see my point??
SavainL
In article <4lprvk$1...@newsbf02.news.aol.com>, lb...@aol.com (Lbsys)
writes:
>Im Artikel <4lol62$f...@newsbf02.news.aol.com>, sav...@aol.com
>(SavainL) schreibt:
>
>>[...]
>>>>>> [I cited *someone* else ... ]
>>>An identity is a statement which
>>>is always true. An equation is a statement which is almost always
>>>false and that's why the case (or cases) for which it is true are of
>>>special significance. f = ma is an equation.
>>><<<<<<
>
>>Would you be so kind as to clearly point out the cases in physics
>where 'f = ma' is false?
>
>No, b/c that was not what the quote says. The singular used above
>stands for 'all', thus the statement reads that from the quantity of
>all possible equations, most are false and if we find one, that holds
>true, we should have a good look, as 'it is of special significance'.
>Would you care to do a little thinking and not always conclude first
>hand that all other people are plain stupid?
If you want to believe that 'f = m*a' is a special case I wouldn't say
that it makes you stupid. Many people believe it and in fact, I used to
believe it too. I just don't believe it anymore. I admit that my opinion
on 'f = m*a' is biased because I, like everyone else on this forum, have
an agenda, and my agenda is that we are swimming in a sea of energetic
particles and this sea of energy is not the "spacetime metric" of
relativity. It is a sea of real particles.
Now, as far as the "identity vs. equation" business is concerned, my
definition of identity is simple: it is an equation that is *always*
true. Not all equations are identities but all identities are equations.
I believe 'f = m*a' *IS* an identity. It's just my opinion. You don't
have to accept it, just like I don't have to aceept your opinion that it
is just a special case. I do however have very compelling reasons to hold
my current belief.
'f = m*a', IMO, is the key to identifying the sea of energetic particles
that I'm talking about. The minute you accept that 'f = m*a' is an
identity, i.e., that mass and acceleration are all there is, then this sea
of enegetic particles comes roaring into full view through sheer force of
reason.
What causes acceleration? Is it force? Sure, that is, if you give
force its own independent existence. But if you say that acceleration is
simply caused by particle interactions (which is what I'm saying), then it
is clear that 'force' is not a primitive or fundamental concept which can
be **independently** defined as vector quantity.
The notion that 'f = m*a' is not true in **all** cases where forces are
present is, in my humble opinion, is an archaic view. It is tantamount to
wearing blinders. Remove the blinders and then you can clearly see the
vast crystal-like expanse of energetic particles, my proposed 4-D lattice
of particles, the one which is responsible for both gravity and
electromagnetic phenomena. Just my opinion. :-)
Scott Ellsworth
In article <Ramsay-MT-260...@delphi.bc.edu>,
Keith Ramsay <Rams...@hermes.bc.edu> wrote:
>
>In article <qmsDqD...@netcom.com>, q...@netcom.com (Scott Ellsworth) wrote:
>|each possible outcome. As to how thistakes place, Wheeler did not state,
>|and it may not be possible to without some way of existing in the
>|hyperrealm which this is imbedded in.
>
>individually resemble "worlds", by a metaphor well worth being careful
>about.
Yes, very true. Under Wheeler's formulation, what we perceive as a
wave function collapse only looks like one because we see only one of the
possible states. The appearance that the wave function has selected one
and only one state is an artifact of perception.
Is that a fair summary? (It has been a while since I last read this
in real detail)
SavainL
The following was originally sent via email. So was the referenced post
by Levanto. Additions are in curly brackets.
mikko....@vtt.fi (Mikko Levanto) wrote:
>I don't think it is correct to call spacetime a mapping. It is
>those events and the individual and collective properties of those
>events. If the events exist, so does the spacetime, otherwise not.
This is arguable. See below. BTW, why don't you post this to
sci.physics?
>> Say what? I thought physics was an empirical science. If you
>> cannot prove something, why insist on talking about it as if it were
>> true?
>
>Sometimes that may make it easier to talk about something that
>can be proven, at least to those who already know the style.
>So why not? Non-reality of nature is unprovable, at least with our
>present skills, so why to mention it?
Baez and everyone else involved in this didscussion knew that they were
dealing with layfolks. Why are you apologizing for them?
>> >In other words, before Einstein the metric seemed like a very
>> >abstract thing, a matter of mere "geometry" rather than physics.
>> >Einstein realized it was a living, pulsing, physical field just like
>> >electromagnetism. He realized that in this case, geometry was
>> >really physics. These days people might say: physics was really
>> >geometry!
>>
>> Does this sound like a mere interpretation to you? Does it not
>
>More like poetry.
Sorry, poetry has no place in this discussion especially blatant,
know-it-all, arrogant poetry like Baez's. This is science.
>> clearly show that Baez thinks that the "spacetime metric" is a real
>
>Not clearly, only opinions of others (Einstein, people [of these days])
>are presented, probably because they are considered worth of
>consideration.
Why do you people insist on covering up your mistakes? Not all
non-physicists are entirely stupid, you know. When you present an opinion
it is only the honest thing to do to clearly label it as such.
>> physical structure that's *directly causing* things to happen? I
>> could be wrong. So please correct me.
>
>Does it make sense to assume that there is (always or sometimes) some
>direct cause that makes a thing to happen? If yes, then it also
>makes sense to assume a physical structure for that cause. A
>postulated structure can be called "spacetime metric" if it has
>most of the properties that one would expect from a metric in a
>mathematical theory.
I'll be the first to argue that there is an expanse of (so far
intangible) substance through which normal matter seems to move. Calling
it "metric" is stretching the imagination to the limit. The word metric
has no concrete meaning. It is entirely abstract word that means
essentially, "measurement". That's why it is only fair to expect that the
**real tangible cause** will eventually be found. And it won't be no darn
"metric", either.
>> >Unfortunately it is hard to explain something to laymen without
>> >using one of the possible interpretations.
>> >
>> > You know, I don't know if you realize this, but this is an
>> >deceitful, insulting, and condescending thing to say to others. Why
>> >not simply tell the truth?
>
>It may be deceitful, insulting, and condescending, but I think it
>is the truth.
Well, that makes you an arrogant fool just like everyone else.
{including yours truly}
>> If the truth is that spacetime is but a mapping of events, I
>> don't see what's so hard to understand.
>
>If the spacetime were a mapping, one would have to ask, a mapping
>from what to what. Otherwise one can't understand anything about
>a mapping. But I don't think it is.
By "mapping" I mean a graphing aid. Events are just plotted onto it.
Maybe "mapping" is the wrong word. What difference does it make?
>> I'm a layperson and I don't have any trouble understanding it.
>Maybe it is something that only a layperson can understand.
Well I would not call Jan Bielawski a layperson. Why don't you post
your entire message to sci.physics? Emailing it to me useless in this
regard.
>BTW, what exactly do you mean by that word? I've often heard
>laypersons to use that word and wondered what they mean.
We are all laypersons in one field at one time or another. If you don't
know what it means, your foolishness and arrogance are showing. {by
layperson I mean a person who has not received formal training in a
particular field}
>[...]
>> >Sorry, cause and effect are connected with spacetime. At least in
>> >the following sense: There is some event which may have a causal
>> >influence on some other event. We can do now a lot of measurements
>> >using clocks, light and so on, and based on these measurements we
>> >can decide if such a causal connection is possible.
>>
>> I don't have a problem with that. There is *indirect* causation.
>> The *spacetime mapping* simply shows how the cause (event 1) is
>> indirectly connected to the effect (event 2). That's fine. But I
>> refuse to accept the notion that's being bandied about by many that
>> somehow there's a direct cause and effect connection between the
>> *mapping itself* and the events.
>
>Unless you accept that there is some physical mechanism between
>the two events (cause and effect), you should not call it "indirect".
Where have you been? I clearly said so in my posts. You'll just have a
hard time convincing me it's some abstract "metric".
>> When the actual intermediate causal
>> mechanism (quantum gravity?) is finally found, then its predictions
>> can be compared with reality and with the predictions of GR to
>> determine its accuracy.
>
>In the mean time the predictions of GR can already be compared
>ith reality.
What's your point? I'm not knocking GR. Only your
"spacetime-exists-apart-from-matter-and-it-curves" interpretation of it.
I don't believe it because nothing moves in spacetime. GR is great as a
predictive tool. Nothing else. Just like Newtonian mechanics.
>> >John Baez explanations make sense. It is simply another
>> >interpretation of the same theory.
>>
>> He should have come right out and forewarned all readers,
>> especially
>> layfolks, that he was simply "interpreting". He did not do so.
>
>Do you always warn that everything you say is an interpretation?
"Interpretation" is just another word for "speculation". Whenever I
think I'm speculating I use words like "I think" or "I postulate" or "I
hypothesize" or "in my opinion". Many people do that when they post their
opinions. Not doing so, like Baez, is the utmost of arrogance. Most
physicists who post on sci.physics are in fact a bunch of arrogant
know-it-all jerks no less so than most of the non-physicists {of which I
am one, BTW. But so what if sci.physics consists of jerks talking to
jerks? Information still finds its way through. And I'm getting used to
it. :-) }
SavainL
In article <DqI3F...@midway.uchicago.edu>, me...@cars3.uchicago.edu
writes:
>The point is that there is only one preexisting idea of "f" that's
>needed, which is that "f" is tied "somehow" to an interaction, i.e.
>to an external factor. That suffices to see it as "completely
>different a priori" from "a" which is a property of the body alone.
I know you probably have me in your killfile by now but I feel I must
intervene here to point out something for those who don't have me in their
killfile. I cannot understand how "a" can be the property of a body
alone. If a body's acceleration is due to its sustained interactions with
other entities, there's simply is no way that "a" can be the property of a
single body.
>[...]
>
>The reason is that "f" and "a" can be
>measured separately, thus the relation may be falsified.
To prove this may be impossible because one would have to conduct
microscopic force measurements instantaneously, i.e., having zero
duration. I maybe wrong here.
It is true that on the surface "f" may seem independent of "a". The
inverse does not seem to be true however. "a" is always accompanied by
"f". To prove experimentally that "f" is always accompanied by "a" would
take some doing. Logically, it is reasonable to expect that if an effect
can be measured, then it must have a cause. In the example of two equal
and opposite forces in which there appears to be zero acceleration on the
surface, it is logical to suppose that some cause must be at play. One
normally expects cause and effect to always require change, i.e., motion.
Otherwise they simply don't exist. There's every reason to suppose that
the same quantity of invisible, causal interactions is taking place to
maintain a force of known magnitude, whether or not the force is
counteracted by another. If the invisible causal interactions cease, so
does the force.
I strongly suspect that in all cases where 2 or more forces are at play
on a body, any observed acceleration is the result of the vector additions
of a large number of microscopic accelerations. These can only take place
if one also postulates a large number of interactions. These interactions
require energy to maintain. The energy cannot come from the body itself.
It must come from somewhere else.
There's a lot more to bodies at rest (or inertial motion) than meet the
eye. There's an invisible tug of war going on. That is, only if you
accept that 'f = ma' is an identity. :-)
LBsys
Im Artikel <4lrtta$i...@newsbf02.news.aol.com>, sav...@aol.com (SavainL)
schreibt:
> 'f = m*a', IMO, is the key to identifying the sea of energetic
particles
>that I'm talking about. The minute you accept that 'f = m*a' is an
>identity, i.e., that mass and acceleration are all there is, then this
sea
>of enegetic particles comes roaring into full view through sheer force of
>reason.
Right-eoh! Although I have been following the 'Inertial motion' thread
with scrutiny I must have missed this explanation of your point of view.
Or maybe it wasn't layed out openly like this? Did you probably hide this
part of your thoughts so not to deter 'conventional' physicists in the
first place?
I wouldn't say that your view is 'stupid first hand', it surely is allowed
to at least think along these lines to find out, where it leads us to.
Now, for my full understanding, explain the following to me, please:
The term 'a' means acceleration, i.e. a change of velocity over time in a
certain direction. A 'sea of energetic particles' in my view can thus only
'move' matter in forms of 'pressure', which is 'greater on the buck soide
then on the neck soide' (as Arlo Guthrie had put it in his motor-pickle
song), somthing like that. But we certainly run into all kinds of trouble
with this sort of model. As you have shown not to be underrated, you must
have thought of this, so most probably your model is something else -
which I didn't understand by now. :-(
Cheerio
Lorenz Borsche
It's not the river that flows, but the water.
It's not time that is passing by, but us. [N.N.]
me...@cars3.uchicago.edu
In article <4lrmn6$d...@pipe8.nyc.pipeline.com>, egr...@nyc.pipeline.com (Edward Green) writes:
>'me...@cars3.uchicago.edu' wrote:
>
>>I'll put a slightly different slant on it (hope you don't object).
>
>I only become curmudgeonly under personal attack, not when somebody
>disagrees with me. I have never perceived anything but professional
>courtesy from you, so I hope you will continue to put different slants on
>things. I hope you will allow sometimes that in areas of my competence,
>I may sometimes disagree.
>
the same and talk the same then oneof them isn't needed".
... snip ...
>Now, let's bring test mass #1 up to bat and strap on a little standard
>issue test rocket to it, which will serve as a *reproducible* force
>(assume the rocket has negligible mass). So, we release the mass (in
>intergalactic space, of course :-) and pffft! the little rocket fires
>off, during which interval we record an average acceleration. Sooo....
>let's "define" (give me a minute here) the "force" to be f_1 = (m_1)a_1.
> So far, we haven't done anything except write one symbol for two. Ok?
>
>Now, let's bring mass #2 up to the plate, and pffft! we calculate f_2 =
>(m_2)a_2. Now (assuming our standard rockets have reasonable quality
>control :-) we make a momentous discovery:
>
> f_1 =~ f_2
>
>Cosmic! Now we have some physics. We excitedly test this generalization
>for many different masses, and find that.... f_i is distributed as a
>Gausian random variable! (Ha... I bet you thought I was going to say they
>were all equal :). Hmm... Maybe force is non-deterministic? Being bold
>theorists though, we confidently assert: "The variation in f_i is do to
>minute uncontrollable variations in manufacturing the rockets, in weighing
>the masses, and measuring the trajectories. We therefore conjecture
>that if we could meaurse the *real* physical quantities, we would always
>have:
>
> f = ma
>
>So this is why I balk a bit at the idea of "tying together two completely
> different quantities". Notice according to my development, we had no
>*preexisting* idea of "f".
OK, let me intervene here for the moment. We're in full agreement.
The point is that there is only one preexisting idea of "f" that's
needed, which is that "f" is tied "somehow" to an interaction, i.e.
to an external factor. That suffices to see it as "completely
different a priori" from "a" which is a property of the body alone.
Once, due to observation of data, or hunch, or whatever, you start
thinking this way, then the rest is a matter of developing a proper
procedure, bootsrap most likely.
... snip ...
>
>Do you see my point? It's possible for an equation to *both* define a new
>physical quantity *and* contain real physics, provided the definition is
>stated in such a way that it *might* fail to be consistent -- as you say,
>it's an equation, not an identity. Maybe we could call this the
>"bootstrap" definition of physical properties; definition and physical law
>rolled into one!
Well, a bit of nitpicking here. You may call it "a definition", but
no, it is still an equation. The reason is that "f" and "a" can be
measured separately, thus the relation may be falsified. A definition
cannot be falsified since once of the quantities involved exists only
in terms of some numerical relationship with the other. For example
beta = v/c
for the relativistic beta, is a definition. It really just means
"naming convention". Of course it is perfectly sensible, during the
early development state of the theory to use a definition like
your force definitions above. But eventually the two quantities must
be measurable separately since they are indeed inherently different.
>
... snip ...
>Do you see my point??
>
I'm sorry to tell you that we are mostly in agreement. According to
Cosby it means that at least one of us is mostly superfluous :-)
Edward Green
'me...@cars3.uchicago.edu' wrote:
>OK, let me intervene here for the moment. We're in full agreement.
>The point is that there is only one preexisting idea of "f" that's
>needed, which is that "f" is tied "somehow" to an interaction, i.e.
>to an external factor. That suffices to see it as "completely
>different a priori" from "a" which is a property of the body alone.
could bootstrap the measurement of f *and* newton's law simultaneously,
without any a priori means of measuring f other than the equation itself,
I realize I assumed some previous concept of a "force", i.e., it's
associated with our little test rocket, external and independent of the
test body, etc.
That was at least half the work to "discovering" newton's law this way,
the other being identifying some function of the other variables constant
for fixed model of rocket. "ma^2"? "m^a"? Good thing nature was simple!
>Once, due to observation of data, or hunch, or whatever, you start
>thinking this way, then the rest is a matter of developing a proper
>procedure, bootsrap most likely.
>
> ... snip ...
>>
>>Do you see my point? It's possible for an equation to *both* define a
new
>>physical quantity *and* contain real physics, provided the definition is
>>stated in such a way that it *might* fail to be consistent -- as you say,
>>it's an equation, not an identity. Maybe we could call this the
>>"bootstrap" definition of physical properties; definition and physical
law
>>rolled into one!
>
>Well, a bit of nitpicking here. You may call it "a definition", but
>no, it is still an equation. The reason is that "f" and "a" can be
>measured separately, thus the relation may be falsified.
Odd. We seemed to have been in perfect agreement. Must be some semantic
difficulty. When I say "definition" I mean "operational definition" of
course. I think we realize that. When you say "may be falsified" I
think I would prefer to say "may fail to be self consistent". Maybe I
should rephrase my idea:
Newton's second law *may* be taken to be a "self-consistent
operational definition of the (numerical value of) force".
It is an "operational definition" because, given some interaction of
unknown magnitude we may as well "define" the magnitude by the dynamic
result of setting it against some test mass: it is "self-consistent"
("falsifiable") because this "operational definition" allows us to use
*any* test mass, and a priori we might get different results... but we
don't!
There.... do you taste the exquisite flavor of the epistemology now? ;-)
>A definition
>cannot be falsified since once of the quantities involved exists only
>in terms of some numerical relationship with the other. For example
>
> beta = v/c
>
>for the relativistic beta, is a definition. It really just means
>"naming convention".
Of course. So maybe to emphasize the distinciton I should call this a
"self-consistent *falsifiable* operational definition".
Once more: Operational, because it tells us how to assign a numerical
value to any stray "force" that wanders in the room. Falsifiable, because
we left a choice -- *any* mass could be used, and we may conceivably get
different results. Self-consistent, because we don't.
We *could* have specified an operational definition in terms of some sacred
test mass kept in a helium filled vault between experiments. Then the
operational definition would not have been falsifiable. But we allow any
old mass to serve, and so it is falsifiable. A self-consistent
falsifiable operational definition introduces a new physical concept to us
*and* states a physical law involving it, all rolled into one. It's the
free phyiscal law force gets without further obligation, just for joining
the club of physical variables! Join today.
>Of course it is perfectly sensible, during the
>early development state of the theory to use a definition like
>your force definitions above. But eventually the two quantities must
>be measurable separately since they are indeed inherently different.
I would prefer to say that in a mature state of the theory, we have
multifarious ways of measuring any of the variables in terms of other,
well characterized quantities, and we may lose sight of the order of
precedence. Indeed, I hold that any such order eventually becomes
irrelevant, and I think you would agree, because a mature theory amounts
to a kind of self consistent web of numbers we have assigned to various
aspects of the universe; mass to the rock we hold in our hand, force to a
well characterized interaction, velocity to a trajectory, and yes, even
length and time... they are defined by kind of a self-consistent bootstrap
process too. What a shock when it turned out our entire comfortable web
of operational relations between length and time was not completely
self-consistent! It caused quite a stir. ;-)
> ... snip ...
>
>>Do you see my point??
>>
>I'm sorry to tell you that we are mostly in agreement. According to
>Cosby it means that at least one of us is mostly superfluous :-)
Maybe after the foregoing, both of us can stick around a while longer.
:-)
SavainL
In article <4lsnf2$q...@newsbf02.news.aol.com>, lb...@aol.com (Lbsys)
writes:
>Im Artikel <4lrtta$i...@newsbf02.news.aol.com>, sav...@aol.com
>(SavainL) schreibt:
>
>> 'f = m*a', IMO, is the key to identifying the sea of energetic
>>particles that I'm talking about. The minute you accept that
>>'f = m*a' is an identity, i.e., that mass and acceleration are all
>>there is, then this sea of enegetic particles comes roaring into full
>>view through sheer force of reason.
>
>Right-eoh! Although I have been following the 'Inertial motion' thread
>with scrutiny I must have missed this explanation of your point of
>view. Or maybe it wasn't layed out openly like this? Did you probably
>hide this part of your thoughts so not to deter 'conventional'
>physicists in the first place?
Thanks for the response. In the"'Inertial Motion: Fact or Fiction?"
thread, I repeatedly postulated the existence of a 4-D lattice of discrete
particles *without which* normal matter cannot possibly move.
>I wouldn't say that your view is 'stupid first hand', it surely is
>allowed to at least think along these lines to find out, where it leads
>us to. Now, for my full understanding, explain the following to me,
>please: The term 'a' means acceleration, i.e. a change of velocity
>over time in a certain direction. A 'sea of energetic particles' in my
>view can thus only 'move' matter in forms of 'pressure', which is
>'greater on the buck soide then on the neck soide' (as Arlo Guthrie had
>put it in his motor-pickle song), somthing like that. But we certainly
>run into all kinds of trouble with this sort of model. As you have
>shown not to be underrated, you must have thought of this, so most
>probably your model is something else - which I didn't understand by
>now. :-(
Right. Your objection is well formulated and perfectly valid given the
conventional understanding of motion. I like the Arlo Guthrie bit. The
whole purpose of the 'Inertial Motion' thread and the discussion about
"cause and effect" was to hypothesize that:
Matter cannot move without a cause. <-- conjecture 1
By this I mean,
There can be no motion without interaction. <-- conjecture 2
If a particle is caused to jump from one position of the lattice to
another, it comes to an immediate halt. If there were no particles to
interact with at this new position, the motion of the particle would
completely cease. That is, until another particle comes into contact with
it. Inertial motion is therefore a sustained repetition of micro jumps or
quantum jumps, if you will resulting from repeated interactions with the
particles of the lattice. A change in the instantaneous speed of the
jumps translates into observed acceleration at the macroscopic level.
An interaction occurs when 2 particles have the same coordinates, i.e.,
when the distance between them is zero. Motion does not occur as a result
of pressures from one side of the other. Direct interaction is needed
because two particles cannot interact if they are simply juxtaposed. The
term 'pressure' is a macroscopic phenomenon resulting from a large number
of interactions. It means nothing at the microscopic level. At this
level "cause and effect" is just an other way of saying "interaction".
The sea of particle (the lattice) offers no resistance to motion: In
fact, it facilitates or enables the motion of matter. Motion, as we know
it would be impossible without it.
In conclusion, both the 'motion-needs-a-cause' and the 'f =
m*a-is-an-identity' hypotheses are conspiring to make the "sea of
particles" visible to the mind's eye. It cannot be denied. I hope the
above explanation answers your question.
Stealth
Hello. Can anyone please tell me what Solar Wind actually is? If you
could I would greatly appreciate it.
or email me at : Stealth @sciboard.spdlan.louisville.edu
me...@cars3.uchicago.edu
In article <4lthtf$e...@pipe8.nyc.pipeline.com>, egr...@nyc.pipeline.com (Edward Green) writes:
>'me...@cars3.uchicago.edu' wrote:
>
My server went down when I started responding so here is another try.
Yes, you can call it "self-consistent operational definition" but it
shouldn't obscure the fact that it is an equation. Or, to put it
another way, you can start the process with some definition, but when
you go along and perform the measurements most (almost all)
definitions will fail the test of self consistency and will have to be
discarded. The one that survived the test has been elevated to the
status of "law of nature", it is not just a definition anymore. By
maintaining the word "definition" you may make somebody think "well,
Newton's laws are only definitions, I can define things different way
and have a different physics".
>
>There.... do you taste the exquisite flavor of the epistemology now? ;-)
But of course.
>
>Of course. So maybe to emphasize the distinciton I should call this a
>"self-consistent *falsifiable* operational definition".
>
>Once more: Operational, because it tells us how to assign a numerical
>value to any stray "force" that wanders in the room. Falsifiable, because
>we left a choice -- *any* mass could be used, and we may conceivably get
>different results. Self-consistent, because we don't.
>
>We *could* have specified an operational definition in terms of some sacred
>test mass kept in a helium filled vault between experiments. Then the
>operational definition would not have been falsifiable. But we allow any
>old mass to serve, and so it is falsifiable.
Right. using only a single mass, or a single force, it would remain
just a definition. Look on this mathematically. Suppose you have N
dorces and P bodies available. You postulate a relation in the form
of f = ma and perform measurements using every force with every body
do get the accelerations. So you get N*P equations for your N + P
unknowns (the unknowns are forces and masses). The set is
"falsifiable" if it is overspecified i.e.
N*P > N + P
or
1 > 1/P + 1/N
If either N or P is one the inequality isn't fulfilledand you can
assign any values you wish without getting a contradiction. If N=P=2,
(that's the "pathological" case) the inequality becomes an equality
and you have unique but not falsifiable values. In all other cases
the system is falsifiable.
>
... snip ...
>I would prefer to say that in a mature state of the theory, we have
>multifarious ways of measuring any of the variables in terms of other,
>well characterized quantities, and we may lose sight of the order of
>precedence. Indeed, I hold that any such order eventually becomes
>irrelevant, and I think you would agree, because a mature theory amounts
>to a kind of self consistent web of numbers we have assigned to various
>aspects of the universe; mass to the rock we hold in our hand, force to a
>well characterized interaction, velocity to a trajectory, and yes, even
>length and time... they are defined by kind of a self-consistent bootstrap
>process too. What a shock when it turned out our entire comfortable web
>of operational relations between length and time was not completely
>self-consistent! It caused quite a stir. ;-)
>
Yep. For good reason. Whan a self consistent system starts falling
apart, you're kinda shocked.
>>>
>>I'm sorry to tell you that we are mostly in agreement. According to
>>Cosby it means that at least one of us is mostly superfluous :-)
>
>Maybe after the foregoing, both of us can stick around a while longer.
>:-)
>
Well, yes, at least till everybody killfiles us. :-)
Keith Stein
>In article <EWCxvDAw...@sthbrum.demon.co.uk>, Keith Stein
><sth...@sthbrum.demon.co.uk> writes:
>
>
>> As soon as you make 'c+v=c'
>> you gotta twist hell out of space and time
>> to make the sums work out; AM I RIGHT?
>
In article <4lls8g$i...@newsbf02.news.aol.com>, SavainL <sav...@aol.com>
writes
> Probably but I don't know at this point. I'm just now digging deeply
Of course i'm not suggesting you take my word for it Louis,
but
In my experience, the deeper you dig into SR, the more difficult
it is to see where it is wrong. I think that is because the error is
right at the beggining, i.e. in the postulates. Once you accept that
the velocity of light could be constant for all observers you are
finished.
Just trying to be helpfull,Louis. Good luck with your researches.
Keith Stein
SavainL
In article <7D346OAa...@sthbrum.demon.co.uk>, Keith Stein
<sth...@sthbrum.demon.co.uk> writes:
>[...]
> Of course i'm not suggesting you take my word for it Louis,
> but
> In my experience, the deeper you dig into SR, the more difficult
>it is to see where it is wrong. I think that is because the error is
>right at the beggining, i.e. in the postulates. Once you accept that
>the velocity of light could be constant for all observers you are
>finished.
>
> Just trying to be helpfull,Louis. Good luck with your researches.
>Keith Stein
Thanks for the help and the wish. One of the things that I usually
investigate thoroughly are the premises of a theory. So if I see anything
funny, I'll stop there. You are probably right about getting confused and
lost as one gets deep into a complex convoluted theory. I've said many
times that a final theory of reality had better be as simple as can be,
otherwise you can bet your life it's not final. Most likely it's just
plain false.
Anyway, I was thinking that the only way to displace SR (if found
necessary) is to come up with a new theory that has more accurate
predictions than SR. Completely new preditions would be even better.
BTW, I agree with the title of the thread in a deep Eleatic sense having
little to do relativity. There is indeed no space. Space as a place
where everything resides has got to be one of the most absurd things going
around. I **believe** that everything is ONE and position is an intrinsic
property of particles. Particles are all there is. The logical and
philosophical ramifications of this assertion should surely gain me a
place in the killfiles of a lot of people. But who really cares? What
matters is understanding and understanding is fun.
LBsys
Im Artikel <4ltq63$4...@newsbf02.news.aol.com>, sav...@aol.com (SavainL)
schreibt:
>I like the Arlo Guthrie bit.
Good :-)
>..... I hope the
>above explanation answers your question.
Hi Louis,
Ok, what do you think of opening a new thread called 'I don't want a
pickle' (which is the first line of the motorcycle song), where we could,
one by one, discuss the alternative models of our physical nature, so that
- just by the satiric nature of the title - no one following the accepted
lines, would be tempted to jump in and heat up?
I'm going to try that and will start with your lattice explanation from
above and put up a few questions to you about it. I hope you join in. And
Ed of course and maybe Glird and others.
Mikko Levanto
SavainL wrote:
> By "mapping" I mean a graphing aid. Events are just plotted onto it.
> Maybe "mapping" is the wrong word. What difference does it make?
I see. I thought you were thinking of the mathemathical meaning
of mapping.
This way to think is fine for the Newtonian or SR spacetime,
where the spacetime is always the same, independent of matter
content. But it does not work for the General Relativity, where
the spacetime depends on the matter content, and not only for
metric but event, at least to some extent, for topology. E.g.,
one can show that with reasonable assumptions about the matter
content the GR spacetime cannot have infinite extesion in past.
With some additional assumptions one can show that the future
is not infinite, either. More generally, the size and shape of
the GR spacetime depend of the matter content. No such conclusions
can be made about Newtonian or SR spactimes. I don't know,
what would be the best words to describe the GR spacetime,
but at least it is different.
SavainL
In article <3184F9...@vtt.fi>, Mikko Levanto <mikko....@vtt.fi>
writes:
>SavainL wrote:
>> By "mapping" I mean a graphing aid. Events are just plotted onto
>>it. Maybe "mapping" is the wrong word. What difference does it make?
>
>I see. I thought you were thinking of the mathemathical meaning
>of mapping.
>
>This way to think is fine for the Newtonian or SR spacetime,
>where the spacetime is always the same, independent of matter
>content. But it does not work for the General Relativity, where
>the spacetime depends on the matter content, and not only for
>metric but event, at least to some extent, for topology. E.g.,
>one can show that with reasonable assumptions about the matter
>content the GR spacetime cannot have infinite extesion in past.
>With some additional assumptions one can show that the future
>is not infinite, either. More generally, the size and shape of
>the GR spacetime depend of the matter content. No such conclusions
>can be made about Newtonian or SR spactimes. I don't know,
>what would be the best words to describe the GR spacetime,
>but at least it is different.
I agree with you that it's different. But how do you propose to show
that the spacetime of GR is not infinitely extent in the past and the
future, given that nothing moves in spacetime, curved or not? That's the
part I'm having great difficulties with.
Ilja Schmelzer
>> By "mapping" I mean a graphing aid. Events are just plotted onto it.
>> Maybe "mapping" is the wrong word. What difference does it make?
>I see. I thought you were thinking of the mathemathical meaning
>of mapping.
>This way to think is fine for the Newtonian or SR spacetime,
>where the spacetime is always the same, independent of matter
>content. But it does not work for the General Relativity, where
>the spacetime depends on the matter content, and not only for
>metric but event, at least to some extent, for topology. E.g.,
>one can show that with reasonable assumptions about the matter
>content the GR spacetime cannot have infinite extesion in past.
>With some additional assumptions one can show that the future
>is not infinite, either. More generally, the size and shape of
>the GR spacetime depend of the matter content. No such conclusions
>can be made about Newtonian or SR spactimes. I don't know,
>what would be the best words to describe the GR spacetime,
>but at least it is different.
Spacetime is much more confusing, as may be seen from your posting.
What GR describes is not more than the result of a certain physical
measurement made with an apparatus named "clock". It is reasonable to
assume that gravity - as a universal force - has also an influence on
this apparatus. It is not excluded to assume that there may be
situations (with strong, increasing gravitational field) which may
cause this apparatus even to stop.
This reasonable and simple physical effect of gravity tells simply
nothing about the topology of our universe. All it tells is that we
do not measure time with these clocks but something else.
In the Newtonian era it was reasonable to assume that we can use this
apparatus to measure time. But already Newton has pointed out that
this is only an assumption, and it may be that there is no exact
measurement of time by such an apparatus.
In SR and GR it does no longer work. Two twins, which start at a first
place and moment and meet again at a second place and moment see
different results on their clocks. Thus, the clocks don't measure
time, because the time is the same at their second meeting at it was
at their first.
To use the old notion "time" for it is obviously confusing and has
confused a lot of people.
Time is already a reserved word for the thing that subdivides all
events into past, present and future and manages the transformation of
future events into past events we observe. The twin paradox shows that
this is not connected with the results of clock measurement.
To conclude from a measurement which is distorted by known reasons
(gravity), that "our universe" is "curved" or even has a nontrivial
topology is human megalomania, as much as the point of view that
things we cannot measure do not exist.
Ilja
--
My concept for the quantization of gravity: ~/PG/index.html
--------------------------------------------------------------------------
Ilja Schmelzer, D-10178 Berlin, Keibelstr. 38, <schm...@wias-berlin.de>
WWW: ~/index.html "~" means http://www.berlinet.de/schmelzer
--------------------------------------------------------------------------
Edward Green
'me...@cars3.uchicago.edu' wrote:
>Yes, you can call it "self-consistent operational definition" but it
>shouldn't obscure the fact that it is an equation. Or, to put it
>another way, you can start the process with some definition, but when
>you go along and perform the measurements most (almost all)
Of course. If you started out to test the operational definition "f =
ma^2", you would find it failed to be self consistent pretty damn quick!
I thought this went without saying? Maybe not. :-(
> ...and will have to be
>status of "law of nature", it is not just a definition anymore. By
>maintaining the word "definition" you may make somebody think "well,
>Newton's laws are only definitions, I can define things different way
>and have a different physics".
false", just to avoid future argument. This reminds me of a growing
thought... some of the misunderstanding on sci.physics arises from multiple
ideas of its purpose... but that's another thread.
>Right. using only a single mass, or a single force, it would remain
>just a definition. Look on this mathematically. Suppose you have N
>dorces and P bodies available. You postulate a relation in the form
>of f = ma and perform measurements using every force with every body
>do get the accelerations. So you get N*P equations for your N + P
>unknowns (the unknowns are forces and masses). The set is
>"falsifiable" if it is overspecified i.e.
>
> N*P > N + P
>or
> 1 > 1/P + 1/N
>
>If either N or P is one the inequality isn't fulfilledand you can
>assign any values you wish without getting a contradiction. If N=P=2,
>(that's the "pathological" case) the inequality becomes an equality
>and you have unique but not falsifiable values. In all other cases
>the system is falsifiable.
meaning to complex probabilities. You might hope to use the extra degree
of freedom present in a complex number to capture something about
dependency, but you see pretty quickly that for more than two mutually
dependent events there just are not enough degrees of freedom.
I wonder if you could do it with matrices... hmm...
[snip]
>>>I'm sorry to tell you that we are mostly in agreement. According to
>>>Cosby it means that at least one of us is mostly superfluous :-)
>>
>>Maybe after the foregoing, both of us can stick around a while longer.
>>:-)
>>
>Well, yes, at least till everybody killfiles us. :-)
Perhaps you have noticed my clever plan to get off the net then... First I
humor the refusniks, until they say something unguarded like "quantum
mechanics is fundamentally flawed", and I make some annoying reply like "I
am not sure exactly what that means"... killfile
Then I pick little philosophical points with the experts, when I am
tolerably confident I have found a little patch of firm ground to stand on
in the stream... they come to beat at me, but when I won't fall in...
killfile
[You are just a little too wary to fall into the cleverly laid expert
trap... ;-) You take a few pokes at me with a long stick to test my
footing, then just invite me to come in maybe half way to shore, so we
can talk. :-) ]
I have found a small cadre of that most mythical sort though, the educated
and rational layman. So I remain engaged...
SavainL
In article <SCHMELZE.96...@fermi.wias-berlin.de>
schm...@fermi.wias-berlin.de (Ilja Schmelzer) writes:
>[...]
>
>To conclude from a measurement which is distorted by known reasons
>(gravity), that "our universe" is "curved" or even has a nontrivial
>topology is human megalomania, as much as the point of view that
>things we cannot measure do not exist.
Thanks for a clearly written message. It came crashing into my
consciousness like a locomotive. I would add that the very fact that our
measurements
change from one frame of reference to another is strongly indicative of
something absolute going on at a deeper level!
"Megalomania" is much too gentle, IMO. This has to be one of the best
posts I've read on sci.physics. Bravo!
me...@cars3.uchicago.edu
In article <4m522v$b...@pipe6.nyc.pipeline.com>, egr...@nyc.pipeline.com (Edward Green) writes:
>'me...@cars3.uchicago.edu' wrote:
>
... snip ...
>
>>discarded. The one that survived the test has been elevated to the
>>status of "law of nature", it is not just a definition anymore. By
>>maintaining the word "definition" you may make somebody think "well,
>>Newton's laws are only definitions, I can define things different way
>>and have a different physics".
>
>Ok, I dig it. In the same spirit you asked Baez not to say "GR is
>false", just to avoid future argument.
Yes, that's the point. We've enough people busy full time generating
confusion, they don't need our help.
>This reminds me of a growing
>thought... some of the misunderstanding on sci.physics arises from multiple
>ideas of its purpose... but that's another thread.
You start this one and you'll have the thread to outlast all threads.
>
... snip ...
>This reminds me of a recent discussion about the possibilities of assigning
>meaning to complex probabilities. You might hope to use the extra degree
>of freedom present in a complex number to capture something about
>dependency, but you see pretty quickly that for more than two mutually
>dependent events there just are not enough degrees of freedom.
>
>I wonder if you could do it with matrices... hmm...
>
Hmm. More degrees of freedom are always nice. As long as you don't
have more parameters than data points ...
... snip ...
>Perhaps you have noticed my clever plan to get off the net then... First I
>humor the refusniks, until they say something unguarded like "quantum
>mechanics is fundamentally flawed", and I make some annoying reply like "I
>am not sure exactly what that means"... killfile
>
>Then I pick little philosophical points with the experts, when I am
>tolerably confident I have found a little patch of firm ground to stand on
>in the stream... they come to beat at me, but when I won't fall in...
>killfile
>
>[You are just a little too wary to fall into the cleverly laid expert
>trap... ;-) You take a few pokes at me with a long stick to test my
>footing, then just invite me to come in maybe half way to shore, so we
>can talk. :-) ]
You won't get rid of me that easily :-). If you want me to killfile
you, you've to start a movement aimed at overthrowing the tyranny of
the conservative physics establishment which is using its vast powers
to keep the lay masses in bondage. :-)
Keith Stein
In article <4lrtta$i...@newsbf02.news.aol.com>, SavainL <sav...@aol.com>
writes
>
> If you want to believe that 'f = m*a' is a special case I wouldn't say
>that it makes you stupid. Many people believe it and in fact, I used to
>believe it too. I just don't believe it anymore. I admit that my opinion
>on 'f = m*a' is biased because I, like everyone else on this forum, have
>an agenda, and my agenda is that we are swimming in a sea of energetic
>particles and this sea of energy is not the "spacetime metric" of
>relativity. It is a sea of real particles.
Anthony Potts [..........on the "Einstein's Mistake" thread !] wrote:-
But it is still the vacuum. the fact that the zero point is in fact a
boiling maelstrom of tearing bubbling spacetime does not mean that it is
not also a vacuum.
Louis Savain wrote:-
>By all means, do contradict me.
keith stein writes:-
WHAT EVEN BY QUOTING OUT OF CONTEXT !
Personally i would not contradict you,
but it seemed to me that you would
maybe like to comment on what Mr.
Potts of CERN was saying............................. Louis.
Why don't you come in on the "Einstein's Mistake"? Not Scared RU ?:-)
The context in which Mr. Potts' comment originally appeared
is shown below:-
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U.net!CERN.ch!cms1.cern.ch!potts
From: Anthony Potts <po...@afsmail.cern.ch>
Subject: Re: A.E. Meier's Mistake
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On 18 May 1996, Alan "Uncle Al" Schwartz wrote:
> Keith Stein <sth...@sthbrum.demon.co.uk> wrote:
> >
> > THERE IS NO 'uttermost vacuum' ANYWHERE MR. MEIER.
> >
> >The degree of vacuum in outer space is orders of magnitude better than
> >anything obtainable on earth, but even in outer space there is hydrogen.
> >You should know that Alex.
>
> Aw, cmon... it's (infinitely) worse than that. Empty space-time is
> populated with quantum vacuum zero point fluctuations - an average half
> quantum in every mode. That is one large load of quanta. The best way
> to guarantee space-time is filled is to utterly empty it.
>
> --
But it is still the vacuum. the fact that the zero point is in fact a
boiling maelstrom of tearing bubbling spacetime does not mean that it is
not also a vacuum.
--
Keith Stein