On the Correctness of Newtonian Theory
Tom Clarke
concept of context Newtonian (gravity) theory is correct up to
a point and then it stops being correct.
So far as I know Newtonian gravity theory is never correct, there
are only regimes in which it is approximately correct and good
enough for practical purposes.
A simple way to estimate (factor of two or three) the error of
Newtonian theory occurred to me.
According to general relativity, objects fall toward the earth because
the space-time near the earth is curved. This curvature is about
1/light-year, or analagous to a circle of radius 6 trillion miles.
The ratio of the length of the path over which an object falls
to the radius of curvature would then provide an estimate of the
fractional error in Newtonian theory.
For a 6000 mile ballistic missile this would be one part in a billion,
which over a 6000 mile trajectory would amount to 10 microns.
In the laboratory, for an object falling 1 meter, Newtonian theory would
be off by one part in 10^15 for an error or 10^-15 meter or one fermi
which is about the radius of a proton or a neutron.
Now neither of these errors (10 microns/6000 miles, 1 fermi/meter)
is going to make any practical difference that I am aware of so
that the choice can be made to safely use the Newtonian theory in
everyday scale phenomena.
But if scientists were to put their mind to it they could probably
measure these errors and confirm that Newtonian theory is wrong
down to scales of meters. Of the two I'd bet that the 1 fermi/meter
difference might be more easily measurable. Some sort of experiment
where quantum effects on the nucleus provide sensitivity to differences
of order a fermi.
Tom Clarke
Don Watkins III
>So far as I know Newtonian gravity theory is never correct, there
>are only regimes in which it is approximately correct and good
>enough for practical purposes.
So what is it that's wrong with Newton's theory? The fact that its equations
don't give precise answers under certain circumstances?
Or, does it give some false explanation for why such and such occurs? If so,
in what way?
Don Watkins
http://www.don-watkins.com
http://donwatkins.blogspot.com
Helen
.1c51...@posting.google.com>...
> There seems to be an idea that in line with the Objectivist
> concept of context Newtonian (gravity) theory is correct up to
> a point and then it stops being correct.
That is of course nonsense, in line with the complete and utter idiocy
you refer to as the "objectivist concept of context" above.
> So far as I know Newtonian gravity theory is never correct, there
> are only regimes in which it is approximately correct and good
> enough for practical purposes.
That is correct ;-)
> A simple way to estimate (factor of two or three) the error of
> Newtonian theory occurred to me.
>
> According to general relativity, objects fall toward the earth because
> the space-time near the earth is curved. This curvature is about
> 1/light-year, or analagous to a circle of radius 6 trillion miles.
>
> The ratio of the length of the path over which an object falls
> to the radius of curvature would then provide an estimate of the
> fractional error in Newtonian theory.
Careful here: We are talking about a curvature of four-dimensional
space-time; this is not something that is intuitively very easy to
grasp other than by way of vague analogies. In particular, note that
this is not the same as the curvature of one- or two-dimensional
objects, or trajectories, in three-space. The curvature of space-time
that is caused by heavy or rotating objects may or may not affect the
spatial curvature of trajectories or objects.
Otherwise, general relativity hardly needs additional confirmation; it
is one of the most accurately verified theories in the history of
physics. We know by now that given the constancy of the speed of
light, Newtonian Mechanics _cannot_ be right, lest all hell break lose
(meaning violation of energy conservation and other "little" problems
of that sort). We also know that GR and Quantum Mechanics do not play
well together, and that one or both are probably wrong, too.
And of course, Newton was neither as uneducated nor as naive as the
average "objectivist", and was well aware that the relative success of
his theory was no indication of its "truth". More likely than not,
there are no true physical (meaning non-tautological) theories. All we
have are more or less accurate models. Which is entirely sufficient
for our purposes. I'd rather leave the search for "truth" to religious
fanatics and useless fools of philosophers.
-- Helen.
Gordon Sollars
.1c51...@posting.google.com>...
> concept of context Newtonian (gravity) theory is correct up to
> a point and then it stops being correct.
>
> So far as I know Newtonian gravity theory is never correct, there
> are only regimes in which it is approximately correct and good
> enough for practical purposes.
>
> A simple way to estimate (factor of two or three) the error of
> Newtonian theory occurred to me.
Unfortunately, this sort of analysis is not enough. What I have been
trying to drive home are the implications for Objectivism of the
willingness to discount small errors in Newtonian predictions. As far
the existence of small errors go, the Objectivst may hold that perhaps
the correct theory is simply a modification of Newton's that fixes
these errors without making any essential changes to the theory.
Objectivism stresses causal explanation. Therefore, the most telling
objection is that Newton's theory, as part of a causal explanation of
the events we observe, posits the existence of an instantaneous
inverse-square force, a force that in fact does not exist. Thus,
there is no "context" in which Newton's theory is correct, just as
there is no context in which Ptolemy's theory is correct, /from a
causal perspective/.
---
Gordon Sollars
gsol...@pobox.com
Robert Kolker
Don Watkins III wrote:
>
> Or, does it give some false explanation for why such and such occurs? If so,
> in what way?
>
Newton's gravitation does not predict the precession of the perihelion
of Mercury correctly. Einstein's General Theory, does. But Newton's
theory is right in the sense that it is a good first approximation.
General Theory reduces to Newtonian gravity in the case of a weak
gravitational field, so Newton was right up to a first approximation.
General Theory indicates why the gravitostatic force has to be an
inverse square law. Newton got is as a generalization of Kepler's third
law, and not from a deep principle of the stucture of space and time.
Bob Kolker
Robert Kolker
Helen wrote:
> have are more or less accurate models. Which is entirely sufficient
> for our purposes. I'd rather leave the search for "truth" to religious
> fanatics and useless fools of philosophers.
And a hearty amen from the choir. Outstanding, well said. HOO-rah!
Bob Kolker
Helen
8839.0...@mb-m14.aol.com>...
> So what is it that's wrong with Newton's theory? The fact that its equations
> don't give precise answers under certain circumstances?
They _never_ give precise answers, except in the limit of vanishing
mass and relative velocity, which is not terribly interesting...
> Or, does it give some false explanation for why such and such occurs? If so,
> in what way?
They are based on concepts space and time that do not correspond to
reality, leading to a number of fundamentally wrong assumptions.
-- Helen.
Tom Clarke
> Tom Clarke writes:
> >So far as I know Newtonian gravity theory is never correct, there
> >are only regimes in which it is approximately correct and good
> >enough for practical purposes.
> So what is it that's wrong with Newton's theory? The fact that its equations
> don't give precise answers under certain circumstances?
Newton's theory never gives precise answers. Under all circumstances
it is wrong - maybe by a fraction of the width of an atomic nucleus - but wrong
nevertheless.
> Or, does it give some false explanation for why such and such occurs? If so,
> in what way?
It also gives a false explanation for gravity and for the nature of time.
Gravity is some unspecified force that somehow crosses space
(Newton did not speculate on its nature). But the best theory of
gravity know explains gravity in terms of curved space, requiring
no space crossing force.
Time in Newtonian theory is such that the concept of simultaneity
can be defined independent of state of motion. Assuming such
simultaneity contradicts known experiments.
Tom Clarke
Acar
> There seems to be an idea that in line with the Objectivist
> concept of context Newtonian (gravity) theory is correct up to
> a point and then it stops being correct.
OT: This is a good example of contextual truth as a pragmatic device. Truth
is the best that we can do. Correspondence becomes non-contradiction, IOW
coherence.
Helen
48.26...@posting.google.com>...
> Objectivism stresses causal explanation. Therefore, the most telling
> objection is that Newton's theory, as part of a causal explanation of
> the events we observe, posits the existence of an instantaneous
> inverse-square force, a force that in fact does not exist. Thus,
> there is no "context" in which Newton's theory is correct,
Yes, I agree, that is a very important point. It is implicit in what a
couple of the others including me have said, but you made it explicit.
-- Helen.
Rod Nibbe
By this are you suggesting that Newton's fundamental laws should
no longer be taught in undergraduate level physics courses at
major universities in this country?
-RKN
Beaten Paths Are For Beaten Men
Fred Weiss
"Robert Kolker" <bobk...@attbi.com> wrote in message
news:3EA45F08...@attbi.com...
> Newton's gravitation does not predict the precession of the perihelion
> of Mercury correctly. Einstein's General Theory, does.
Yawn. Yes, we know that.
But Newton's
> theory is right in the sense that it is a good first approximation.
A "good first approximation" of what? There are things it predicts and there
are things it doesn't. The things it predicts it predicts, period. It
doesn't predict them "approximately". It didn't "approximately" predict
Uranus and Neptune. It predicted Uranus and Neptune, period.
> General Theory reduces to Newtonian gravity in the case of a weak
> gravitational field, so Newton was right up to a first approximation.
You mean it is right in "a weak gravitational field". Period. It is not
right "up to a first approximation". It is right, period. That's why it was
able to predict 2 new planets and get us to the moon and back.
> General Theory indicates why the gravitostatic force has to be an
> inverse square law.
"Has to be". That's not an "approximation".
If you want to get from here to Kalamazoo, you can get there in an oxcart.
You get there slower than in an automobile, but you get there. And you don't
get there "approximately". No one doubts that it is better to take a car on
a trip to Kalamazoo than an oxcart. But before we could get to cars we first
had to get to oxcarts. There are also places a car can go, speeds it can go
out, and things it can do that an oxcart can't. That's doesn't falsify
oxcarts.
What is "approximate" about the following:
"The discovery of Uranus was accomplished by a man named William Herschel,
who accidentally one night found the new planet. This was an incredible
accomplishment considering no new planets had been discovered for thousands
of years. With this new discovery came many problems with calculating the
orbit of Uranus. Some astronomers had believed that there was a exterior
force of Uranus, however no one was able to prove this until Urbain Jean
Joseph LeVerrier and John Couch Adams found calculations using the Newtonian
laws to detect where the exterior planet may be. The exterior planet was
found by Johann Gottfried Galle who used LeVerrier's calculations to find
what we now call Neptune, the exterior force on Uranus. Unlike Uranus which
was found accidentally Neptune was found in answer to questions of Uranus'
orbit. Both the heliocentric and the Newtonian theories were used with the
findings of these two planets."
http://www.astro.utoronto.ca/~seaquist/sci199y/presentations/dunleavy2.html
Fred Weiss
Fred Weiss
"Tom Clarke" <tcl...@ist.ucf.edu> wrote in message
news:ab311d64.03042...@posting.google.com...
> Now neither of these errors (10 microns/6000 miles, 1 fermi/meter)
> is going to make any practical difference that I am aware of so
> that the choice can be made to safely use the Newtonian theory in
> everyday scale phenomena.
Uh, huh.
> But if scientists were to put their mind to it they could probably
> measure these errors and confirm that Newtonian theory is wrong
> down to scales of meters.
"Wrong" in what sense? In a sense that in your own words makes no practical
difference whatever.
All you are saying is that our current theories enable us perform these
measurements with greater precision, which no one is disputing.
"Less precise" is not equivalent to "wrong". By that reasoning a straight
edge would be "wrong" as compared to an electron microscope. Oh, well, let's
throw out all our rulers.
Fred Weiss
Don Matt
> > concept of context Newtonian (gravity) theory is correct up to
> > a point and then it stops being correct.
>
> OT: This is a good example of contextual truth as a pragmatic device. Truth
> is the best that we can do. Correspondence becomes non-contradiction, IOW
> coherence.
I haven't understood you. Do you mean that there is a truth only to a
specific context and therefore an universal truth is an impossible
goal? I think that if yes it would mean that the positivist (or
Kolkerism, if you desire) claim that only what can be tested is truth.
Or with other words: what you have not tested is only an assumption.
Don.
Robert Kolker
Rod Nibbe wrote:
> By this are you suggesting that Newton's fundamental laws should
> no longer be taught in undergraduate level physics courses at
> major universities in this country?
Gee, I hope not. There are several strong reasons for teaching Newtonian
physics.
1. N.P. is still the very paradigm of a mathematically structured
empirical theory of the world. It was the first succesful such program
and when the world first beheld it, it was like a Revelation from God
(it wasn't, but it seemed that way). Maxwell's theory had a similar effect.
2. The mathermatical techniques that flow from the analytic extensions
of N.P., Langangian and Hamiltonian mechanics are heavily used in all
branches of theoretical physics. Langangian actions and Hamiltonians are
as much a part of quantum theory and general relativity as they are of
classical mechanics in its advanced analytic formulation.
3. For celestial navigation well away from the sun, N.P. is well within
the error range of our instruments and is mathematically tractable.
Solving the Einstein field equations (for example) raw and undiluted is
a daunting task and has only been well done for the spherically
symmetric class of problems. That is why we still let Newton, Lagrange
and Laplace do the driving for our far out probes.
4. N.P. is as much a part of a physicist's tool box and a physicist's
upbring as classical perspective and painting techniques are for a
modern artist. A modern artist still has to go back to the Masters for
his grounding since the basic truths of painting and sculptoring were
manifested in the works of the Masters. Think of Newton, Lagrange,
LaPlace, Hamilton as the Rembrants of the Physicists.
Bob Kolker
Robert Kolker
Fred Weiss wrote:
> "The discovery of Uranus was accomplished by a man named William Herschel,
> who accidentally one night found the new planet. This was an incredible
> accomplishment considering no new planets had been discovered for thousands
> of years. With this new discovery came many problems with calculating the
> orbit of Uranus. Some astronomers had believed that there was a exterior
> force of Uranus, however no one was able to prove this until Urbain Jean
> Joseph LeVerrier and John Couch Adams found calculations using the Newtonian
> laws to detect where the exterior planet may be. The exterior planet was
> found by Johann Gottfried Galle who used LeVerrier's calculations to find
> what we now call Neptune, the exterior force on Uranus. Unlike Uranus which
> was found accidentally Neptune was found in answer to questions of Uranus'
> orbit. Both the heliocentric and the Newtonian theories were used with the
> findings of these two planets."
Newtonian Gravity works as well as Einstiening gravity (relative to the
accuracy of observations) in the very weak field case, which is what you
have for the motions of the outer planets. The defects of Newtonian
gravity become noticable for the motion of planets close to the Sun (or
any other strong gravitational source). Furthermore the purely Newtonian
corrections for the GPS system have about ten times the error rate (in
some of the measuring modes) as do the corrections given by Special
Relativity and General Relatitivy. In short, our GPS system would be
highly ungood if we used just Newtonian mechanics.
See URL
http://18.39.0.30:8080/reports/ocw/index8.224.html
and select the Feb 24 lecture on the GPS system (Viewable through
RealPlayer(tm) the free version). Maybe you will actually learn
something insead of recycling the same old Objectivst crap through you
mental filters.
Bob Kolker
Robert Kolker
Fred Weiss wrote:
>
> "Less precise" is not equivalent to "wrong". By that reasoning a straight
> edge would be "wrong" as compared to an electron microscope. Oh, well, let's
> throw out all our rulers.
If we used the GPS in non-Einstienian mode (no longer turned on by the
way) the bombing of Baghdad whould have looked like the London Blitz
instead of the masterpiece of accuracy it was. Less precise is very
WRONG when you are dropping Tomahawks and JDAMS on target. If the idea
is to kill the Bad Guys and leave the "innocent" civillians intact the
difference bewteen Newton and Einstein is highly critical.
Bob Kolker
Helen
.com>...
> By this are you suggesting that Newton's fundamental laws should
> no longer be taught in undergraduate level physics courses at
> major universities in this country?
No.
-- Helen.
-
Helen
9.atl.mindspring.net>...
> In a sense that in your own words makes no practical
> difference whatever.
It does make a big difference for some things, and a small one for
others, but that is entirely beside the point. Incidentally, when did
you turn into a pragmatist?
> All you are saying is that our current theories enable us perform these
> measurements with greater precision, which no one is disputing.
That is not what is being said at all. The issue has nothing whatever
to do with precision of measurements.
> "Less precise" is not equivalent to "wrong".
We are not talking about "less precise". There is nothing imprecise
about Newtonian Mechanics. Newton's theory is perfectly precise, but
it is wrong. Newton was not the kind of waffler you are accustomed to.
In particular, he did not say "Well, roughly, the acceleration of a
body is more or less proportional to the ratio of the force acting on
it divided by its mass, sometimes at least, and maybe sometimes not,
depending on the context". While that is the kind of bullshit a
hobby-philosopher like you or Rand might babble, that is not the way
physics is done.
-- Helen.
P.S.: You still haven't answered my question as to what you think
"Newton's Theory" actually is. Until further notice I am going to
assume you don't know, in other words, you are vigorously defending
nothing in particular at all. Now go play with the other kinds and
have fun at this cute little game of yours.
Tom Clarke
> "Tom Clarke" <tcl...@ist.ucf.edu> wrote in message
>
> > But if scientists were to put their mind to it they could probably
> > measure these errors and confirm that Newtonian theory is wrong
> > down to scales of meters.
>
> "Wrong" in what sense?
In principle. This is a philosophy newsgroup is it not?
> In a sense that in your own words makes no practical
> difference whatever.
So Objectivism is about what is practical?
It is not about principles?
> All you are saying is that our current theories enable us perform these
> measurements with greater precision, which no one is disputing.
Not sure how the theories enable the measurement.
They motivate the refining of apparatus to achieve greater
measurement accuracy, but I don't think it is the theory that
"enables" the measurements.
> "Less precise" is not equivalent to "wrong".
In science it is. Is it OK to steal 10 cents but not OK to
steal $1000?
> By that reasoning a straight
> edge would be "wrong" as compared to an electron microscope.
Bad comparison. First, a straight edge is not a theory.
Second the tool that might be used to establish a straight line
more accurate than a straight edge would be a laser.
> Oh, well, let's throw out all our rulers.
On the way to work I saw a guy doing surveying work with
a GPS receiver on his back. The antenna stuck up over his
head and he had some sort of control device in his hand.
Looks like we are well on our way to throwing out all the
transits!
But a ruler is good for fairly accurate drawing when you don't
need the muss and fuss of a laser to get the best straight line
possible. Just as Newtonian theory is good enough when
you don't need the extra mathematical complication of
general relativity (which by the way is necessary for
GPS satellites).
Tom Clarke
Don Watkins III
>> So what is it that's wrong with Newton's theory? The fact that its
>equations
>> don't give precise answers under certain circumstances?
Helen writes:
>They _never_ give precise answers, except in the limit of vanishing
>mass and relative velocity, which is not terribly interesting...
You may not find it interesting but that says nothing about the truth of
Newton's work relative(!) to that context.
The point, by the way, isn't really to defend Newton's theory, the point is to
highlight the principles of good epistemology. Newton is just a means of doing
so. That's just as a matter of clarification...after all, I'm no scientist
(obviously!).
>> Or, does it give some false explanation for why such and such occurs? If
>so,
>> in what way?
>They are based on concepts space and time that do not correspond to
>reality, leading to a number of fundamentally wrong assumptions.
As I understand them, they correspond exactly to reality at the macroscopic
level we experience even if they don't correspond in some wider context that we
only infer.
Don Watkins III
>> So what is it that's wrong with Newton's theory? The fact that its
>equations
>> don't give precise answers under certain circumstances?
Tom Clarke writes:
>Newton's theory never gives precise answers. Under all circumstances
>it is wrong - maybe by a fraction of the width of an atomic nucleus - but
>wrong
>nevertheless.
Wrong, by what standard? Given the measurement and the means of measurement
Newton used, the only ones he could have used AFAIK, they are exactly correct.
Are you assuming there's some "metaphysical" ruler by which we define
"precise"? There isn't, you know.
>> Or, does it give some false explanation for why such and such occurs? If
>so,
>> in what way?
>It also gives a false explanation for gravity and for the nature of time.
>Gravity is some unspecified force that somehow crosses space
>(Newton did not speculate on its nature)
Good for him.
>But the best theory of
>gravity know explains gravity in terms of curved space, requiring
>no space crossing force.
Could you clarify, then, what he was saying about gravity? Was it "it is a
force which results in X and Y"? Or was it something closer to "it is a force
that acts in such in such a way causing X and Y"?
Perhaps you can point me in the direction of some primary source data.
>Time in Newtonian theory is such that the concept of simultaneity
>can be defined independent of state of motion. Assuming such
>simultaneity contradicts known experiments.
But it's accurate insofar as it describes what experience directly, no?
Don Watkins III
>"Less precise" is not equivalent to "wrong". By that reasoning a straight
>edge would be "wrong" as compared to an electron microscope. Oh, well, let's
>throw out all our rulers.
This is perhaps one of the most important points. There is no "metaphysical
ruler". There are only means of measurement employed by humans all of which
are completely accurate even as they are not equally precise.
Rod Nibbe
Helen wrote:
> No.
But in the post of yours that I replied to you said you agreed with
Gordon that "There is no "context" where Newton's theory is
correct" because "there is no such thing as an instantaneous
inverse square force" (which Newton's theory requires). So why do
*you* think first year physics students should be taught a wrong
theory?
Tom Clarke
> I wrote:
> >> So what is it that's wrong with Newton's theory? The fact that its
> >> equations don't give precise answers under certain circumstances?
> Tom Clarke writes:
> >Newton's theory never gives precise answers. Under all circumstances
> >it is wrong - maybe by a fraction of the width of an atomic nucleus - but
> >wrong nevertheless.
> Wrong, by what standard?
I told you, by sufficiently accurate measurement.
> Given the measurement and the means of measurement
> Newton used, the only ones he could have used AFAIK, they are exactly cor
> rect.
So we are limited to the measurements Newton had available in using
Newton's theory?
Then we could certainly never get to the moon using Newton's theory!
Are we discussing philosophy or the history of science?
> Are you assuming there's some "metaphysical" ruler by which we define
> "precise"? There isn't, you know.
No, I am not assuming that. But it is now the case that human measurement
tools are accurate enough to detect the errors in the Newtonian theory
in many cases.
And - as several have pointed out - the conceptual basis of the theory that
does accurately predict when Newton's theory is wrong is incompatible with
the existents assumed in Newton's theory. So unless the universe is some
sort of patchwork, Newton up to this point, then General Relativity thereafter,
Newton's theory does not correspond to what exists.
> >> Or, does it give some false explanation for why such and such occurs? If
> >> so, in what way?
>
> >It also gives a false explanation for gravity and for the nature of time.
> >Gravity is some unspecified force that somehow crosses space
> >(Newton did not speculate on its nature)
>
> Good for him.
> >But the best theory of
> >gravity know explains gravity in terms of curved space, requiring
> >no space crossing force.
>
> Could you clarify, then, what he was saying about gravity? Was it "it is a
> force which results in X and Y"? Or was it something closer to "it is a
> force
> that acts in such in such a way causing X and Y"?
An attractive force between two bodies of mass m1 and m2 that
acts instantly along the line joining the two bodies with magnitude
F=Gm1m2/r^2. Further, there is a universal time coordinate
such that the motion of a body of mass m with spatial coordinate
x under a force F is governed by F=d/dt[mdx/dt]
The rest is calculus.
> Perhaps you can point me in the direction of some primary source data.
Newton's Principia for the Common Reader by S. Chandrasekhar
> >Time in Newtonian theory is such that the concept of simultaneity
> >can be defined independent of state of motion. Assuming such
> >simultaneity contradicts known experiments.
>
> But it's accurate insofar as it describes what experience directly, no?
Are we talking philsophical matters of principle or matters
of what is good enough in everyday life, what is good enough for
the cave man?
The guy I saw surveying with the back pack GPS this morning was
making use of relativity. He probably didn't give it a thought, but
without relativity, his apparatus would be lucky to get him in the
correct city.
Tom Clarke
Tom Clarke
> Fred Weiss writes:
> >"Less precise" is not equivalent to "wrong". By that reasoning a straight
> >edge would be "wrong" as compared to an electron microscope. Oh, well, let's
> >throw out all our rulers.
> This is perhaps one of the most important points. There is no "metaphysical
> ruler". There are only means of measurement employed by humans all of which
> are completely accurate even as they are not equally precise.
That is so backwards.
Accuracy implys an absolute standard, whereas precision implies repeatability.
If humans pay attention to what they are doing, applying skill and art, they
can make their measurments repeatable. They can achieve precision.
This is what science is all about, different groups repeating experiments
to provide verification and checking of results.
But there is no absolute accurate standard - well other than reality itself.
In the current discussion Newton checked against the orbit of Mercury
or GPS satellite positions is found in error, but general relativity has so
far never been found to be in error. But this does not imply that
general relativity is correct, that it is the ultimate, absolute
standard.
Tom Clarke
Fred Weiss
"Rod Nibbe" <r...@rknibbe.com> wrote in message
news:3EA53D6D...@rknibbe.com...
> But in the post of yours that I replied to you said you agreed with
> Gordon that "There is no "context" where Newton's theory is
> correct" because "there is no such thing as an instantaneous
> inverse square force" (which Newton's theory requires).
I'm not sure what is meant by there being a "thing" - an instantaneous
inverse square force. Did Newton even think there was such a "force" or was
he just simply measuring the motions of bodies which seemed to follow
certain laws with invariable consistency (which they do)?
I'm wondering if the better way to look at this is that we can correctly
look at reality from different perspectives or by focusing on certain
characteristics rather than others. For example you can look at a map from
the perspective of a satellite photo which can encompass a vast terrain of
an entire continent or you can zoom it in - today - down to the individual
street, even house - level. It is not that the one perspective is right and
the other wrong. They are looking at the same basic data differently.
It is not as if given what we know now with GTR that some aspect of the
earth has disappeared and what Newton discovered no longer exists, i.e.that
the "thing" Newton thought he discovered no longer exists or never did and
suddenly there is a new "thing" which has replaced it. He discovered some
things about an aspect of the universe which are true - as true now as when
he discovered them - but now that we have added knowledge we can look at
those same phenomena plus others not grasped by Newton's discovery and see
it in a broader, more comprehensive light.
This is why I imagine Newton is still taught to physics students.
Or the fact that we can't measure microscopic objects with a straight edge
doesn't invalidate rulers. A ruler is still a perfectly valid way to measure
the distance between studs in constructing a house but you couldn't use it
in constructing a semi-conducter chip because you couldn't get the precision
required. The fact that a ruler is less precise, or that from a certain
perspective it might only provide a rough approximation for certain needed
measurements, vs. more advanced measuring instruments doesn't mean rulers
are in error or wrong. They were an important discovery even if they can't
be used to measure everything today.
Fred Weiss
Robert Kolker
Fred Weiss wrote:
> I'm not sure what is meant by there being a "thing" - an instantaneous
> inverse square force. Did Newton even think there was such a "force" or was
> he just simply measuring the motions of bodies which seemed to follow
> certain laws with invariable consistency (which they do)?
He assumed a force, although he was somewhat queasy about a force acting
at a distance with no contact medium intervening. His concept of space
would preclude any kind of an "Einsteinian" explanation. What I wonder
about is that he did not come up with a field theory right off.
Faraday and Maxwell rejected Newtonian type point to point interacting
of charges, such interactions occuring at a distance. Maxwell fleshed
out Faraday's lines of force concept as an extensive field in space.
Maxwell pushed this idea at the same time that Thompson and Weber were
formulating a "Newtonian" model for electrical forces.
Bob Kolker
Fred Weiss
"Don Watkins III" <aynr...@aol.com> wrote in message
news:20030422085840...@mb-m10.aol.com...
> Are you assuming there's some "metaphysical" ruler by which we define
> "precise"? There isn't, you know.
That's simply another way to insinuate the implicit requirement of
omniscience as the standard of knowledge.
It is also implicitly, if not explicitly, saying nothing is "perfectly"
precise which is (1) another variation of the fallacious Zeno paradoxes we
discussed a couple of months ago and (2) a "stolen concept". How would you
know what is precise if nothing is? What's your standard?
The conventional response is then to throw your hands up and declare "We
can't ever know what is really real/ what is actually true" but "screw it,
so long as it "works" it's ok". Why does it "work"? Who knows? Thankfully,
it just does.
You know, it must just be dumb luck that we can get to the moon and back
within inches and seconds of predictions. (Anyway, see, we can't do it
within milliseconds and micro fractions of an inch, so we don't really,
really know what we're doing.)
Fred Weiss
Robert Kolker
Fred Weiss wrote:
> You know, it must just be dumb luck that we can get to the moon and back
> within inches and seconds of predictions. (Anyway, see, we can't do it
> within milliseconds and micro fractions of an inch, so we don't really,
> really know what we're doing.)
Fred. Please stop this. It is perfectly possible to know -how- gravity
works without knowing a cause for gravity. In fact, this is precisely
how it as at this moment. Newton's theory is a close enough predictor to
use for flights to the Moon in back. There was a time when people in
wooden boats managed to sail across the oceans with nothing but a
compass and a sextant. They did not have GPS, but somehow they managed.
The Tahitian navigators, without a north star, constructed a good enough
mental model of ocean currents to get them from Tahiti to the Hawaian
Islands and back. The Tahitians had a method of navigation that was
close enough for the task.
Perfection is not required when adequacy suffices. And remember, the
Best is the Enemy of the Good Enough.
Bob Kolker
Gordon Sollars
@attbi.com>...
> If we used the GPS in non-Einstienian mode (no longer turned on by the
> way) the bombing of Baghdad whould have looked like the London Blitz
> instead of the masterpiece of accuracy it was. Less precise is very
> WRONG when you are dropping Tomahawks and JDAMS on target. If the idea
> is to kill the Bad Guys and leave the "innocent" civillians intact the
> difference bewteen Newton and Einstein is highly critical.
Thanks for showing how everything fits together, Bob. The moral is not
only the practical, but it sets the limits on what theotries of
physics are needed. Objectivists /don't/ care about innocent
civilians, so they see no reason to fault Newton. ;-)
--
Gordon G. SOllars
gsol...@pobox.com
Don Watkins III
>> Wrong, by what standard?
Tom Clarke writes:
>I told you, by sufficiently accurate measurement.
You're confusing precision with accuracy, which is an error.
>> Given the measurement and the means of measurement
>> Newton used, the only ones he could have used AFAIK, they are exactly cor
>> rect.
>So we are limited to the measurements Newton had available in using
>Newton's theory?
Of course not, but in evaluating the truth of his theory it is essential to
specify the context which includes the standards of measurement, both spacially
and temporally.
>Then we could certainly never get to the moon using Newton's theory!
>Are we discussing philosophy or the history of science?
We're discussing the relationship between Newton's theory and reality in order
to highlight the principles of a proper epistemology. Newton's theory is true
in that it correctly describes a particular segment of reality within a certain
range of precision.
True, it does not describe every segment of reality, not even every segment we
know about. Nor is it as precise as the TOR which happens to encompass those
segments of reality correctly described in Newton's theory.
And that's just the point -- knowledge is contextual and later knowledge does
not contradict earlier knowledge, but expands upon it. In this regard, notice
that Newton is still taught in introductory physics classes -- it isn't wrong,
it's limited.
>> Are you assuming there's some "metaphysical" ruler by which we define
>> "precise"? There isn't, you know.
>No, I am not assuming that. But it is now the case that human measurement
>tools are accurate enough to detect the errors in the Newtonian theory
>in many cases.
But they aren't errors, they are limits of precision, and in cases of bodies
moving at higher velocities, limits of applicability. Limits aren't
epistemological disqualifiers.
>And - as several have pointed out - the conceptual basis of the theory that
>does accurately predict when Newton's theory is wrong is incompatible with
>the existents assumed in Newton's theory. So unless the universe is some
>sort of patchwork, Newton up to this point, then General Relativity
>thereafter,
>Newton's theory does not correspond to what exists.
We'll get to that.
>> But it's accurate insofar as it describes what experience directly, no?
>Are we talking philsophical matters of principle or matters
>of what is good enough in everyday life, what is good enough for
>the cave man?
False dichotomy. "Good enough for everyday life" in this context means
"accurate", which Newton's theory is as far as everyday life goes.
>The guy I saw surveying with the back pack GPS this morning was
>making use of relativity. He probably didn't give it a thought, but
>without relativity, his apparatus would be lucky to get him in the
>correct city.
Which goes to show why it's important to constantly expand one's knowledge.
The point isn't that Newton's theory is true in a context and therefore
relativity is worthless. The point is, Newton's theory is TRUE in a context
and thank God, because if it weren't, the moment we discovered the limits of
relativity we'd have to discard that too. And then how the hell would we make
those GPS work?
Don Watkins III
>> This is perhaps one of the most important points. There is no
>"metaphysical
>> ruler". There are only means of measurement employed by humans all of
>which
>> are completely accurate even as they are not equally precise.
Tom Clarke writes:
>That is so backwards.
>Accuracy implys an absolute standard, whereas precision implies
>repeatability.
But there is no "absolute" standard of measurement.
The purpose of measurement is to bring everything within grasp of our
consciousness, therefore all standards of measurement are units we can perceive
or are reducable to units we can perceive.
It is the unit of measurement that determines accuracy. If I say "this table
is fifty inches long" that is accurate so long as I correctly use a ruler. But
it's not as precise as, say, a ruler with more demarcations which allows me to
conclude that this table is 50.2 inches. But they are accurate measurements
relative to the unit of measurement.
And if you want to make things really simple, I'll even allow that one need
state a range -- "This table is between 50 and 51 inches." That is completely
accurate and there's no two ways around that.
Helen
.com>...
> So why do
> *you* think first year physics students should be taught a wrong
> theory?
Because it is a useful theory for most practical purposes. As an
example from a slightly different area, people use continuum mechanics
to describe e.g. fluid flow. Everybody understands that there are no
continuous fluids in the real world, but the Navier-Stokes equations
are good model equations that are often much more manageable,
notoriously difficult though they are, than, say, the Boltzmann
equations.
-- Helen.
Helen
8963.0...@mb-m10.aol.com>...
> >They are based on concepts space and time that do not correspond to
> >reality, leading to a number of fundamentally wrong assumptions.
>
> As I understand them, they correspond exactly to reality at the macroscopic
> level we experience
No they don't. People are usually in very close neighborhood of a body
with significant mass, as you may have noticed...
-- Helen.
John Alway
3.atl.mindspring.net>...
[...]
> This is why I imagine Newton is still taught to physics students.
It should be pointed out that the great bulk of engineering work
that goes on in the world uses Newtonian physics. I've never heard
anyone claim that his three laws of motion are wrong.
...John
Robert Kolker
John Alway wrote:
>> It should be pointed out that the great bulk of engineering work
> that goes on in the world uses Newtonian physics. I've never heard
> anyone claim that his three laws of motion are wrong.
Newton's momentum (mass*velocity) is not conserved in very high speed
collisions. Relatavistic momentum m*v/sqrt(1 -v^2/c^2) is conserved in
all collisions. Newtons second law that defines force as the time change
in momentum is therefore wrong. A similar law involving "relativistic
mass" [1] must be substituted
Bob Kolker
[1] That is m/sqrt(1-v^2/c^2), where m is the rest mass. Real Physicists
do not like this term, but it is intuitive and is handy when talking to
non-physicists who seem to have no trouble with it, at all.
Fred Weiss
"John Alway" <jwa...@hotmail.com> wrote in message
news:dbb7370e.03042...@posting.google.com...
I suspected that was the case but thanks for the confirmation.
"Why are Motion and Newton's Laws Important?
"Engineers analyze motion to understand how things operate under various
chemical, physical, and mechanical conditions. The understanding of motion
can be used to predict an objects motion in future situations.
Engineers use models to predict things such as motion, fluid flow, lift on
an airplane wing, movement of neutrons in a nuclear reactor, deflection of
beams or columns, etc.
Newton's laws are widely used and a good first example of engineering
models."
http://www.foundationcoalition.org/resources/first-year/tamu/course-material
s/newton-laws.html
A Google search of "engineering+Newton's Laws" comes up with nearly 20,000
entries which appear to be listings of introductory engineering, physics,
and astronomy courses at 100's of colleges and universities where Newton's
Laws are taught.
Fred Weiss
Robert Kolker
Fred Weiss wrote:
>
> I suspected that was the case but thanks for the confirmation.
I have already pointed out errors in Newton's second law. However the
relativistic correction (one that preserves the conservation of
momentum) is not that radical. The bad news is that force defined
relativistically does not align with acceleration. Niether is force a
relativistic invariant.
The important quantities in relativistic mechanics are momentum, angular
momentum and energy. In the relativistc correction, force loses the
central role it has in classical mechanics.
You guys ought to read -Spacetime Physics- by Edwin Taylor and John
Archibald Wheeler. The math is not that heavy (no integration, no
differential equations and just a little trigonometry). It explains the
differences between relativistc mechanics and dynamics and classical in
a very clear manner. If you can do the problems, you have three legs up
on relativity theory.
Bob Kolker
Bob Kolker
John Alway
@attbi.com>...
> John Alway wrote:
> >> It should be pointed out that the great bulk of engineering work
> > that goes on in the world uses Newtonian physics. I've never heard
> > anyone claim that his three laws of motion are wrong.
> Newton's momentum (mass*velocity) is not conserved in very high speed
> collisions. Relatavistic momentum m*v/sqrt(1 -v^2/c^2) is conserved in
> all collisions. Newtons second law that defines force as the time change
> in momentum is therefore wrong. A similar law involving "relativistic
> mass" [1] must be substituted
Actually, I knew this. I guess I don't use it, so I had forgotten.
Newtonian mechanics work very well for relatively, no pun intended,
low velocities, but lose accuracy for *very* high velocities.
...John
John Alway
@attbi.com>...
> Fred Weiss wrote:
> >
> > I suspected that was the case but thanks for the confirmation.
> I have already pointed out errors in Newton's second law. However the
> relativistic correction (one that preserves the conservation of
> momentum) is not that radical. The bad news is that force defined
> relativistically does not align with acceleration. Niether is force a
> relativistic invariant.
> The important quantities in relativistic mechanics are momentum, angular
> momentum and energy. In the relativistc correction, force loses the
> central role it has in classical mechanics.
> You guys ought to read -Spacetime Physics- by Edwin Taylor and John
> Archibald Wheeler. The math is not that heavy (no integration, no
> differential equations and just a little trigonometry). It explains the
> differences between relativistc mechanics and dynamics and classical in
> a very clear manner. If you can do the problems, you have three legs up
> on relativity theory.
Well, I integrate all of the time, and use trigonometry virtually
on a daily basis. So, no problem. While I can do differential
equations, I don't much enjoy them. Very difficult. :(
I have read up on this stuff many times, but I guess disuse is a
problem. If you don't use it, you lose it. :/
Out of curiosity, what was/is your profession?
...John
Arnold
"Helen" <GHMoh...@yahoo.com> wrote in message
news:1a8f5fe5.0304...@posting.google.com...
You need to explain why laws which are never correct under
any circumstances should be taught.
--
Arnold
Arnold
> And if you want to make things really simple, I'll even
allow that one need
> state a range -- "This table is between 50 and 51
inches." That is completely
> accurate and there's no two ways around that.
And that is the approximate truth beyond all doubt!
--
Arnold
Robert Kolker
John Alway wrote:
> Well, I integrate all of the time, and use trigonometry virtually
> on a daily basis. So, no problem. While I can do differential
> equations, I don't much enjoy them. Very difficult. :(
>
> I have read up on this stuff many times, but I guess disuse is a
> problem. If you don't use it, you lose it. :/
>
> Out of curiosity, what was/is your profession?
Retired now. Was a software designer by trade and a mathematician by
training.
Bob Kolker
Robert Kolker
Kevin Hill wrote:
> Robert Kolker <bobk...@attbi.com> wrote in message news:<3EA5B295.9080207
> @attbi.com>...
>
> Bob, Helen:
> I vaguely recall this topic being done to death some years ago, but
> can you tell me if it is worthwhile to study David Bohm--not the
> mysticism aspect, but the "ontological interpretation of QM"? It
> always seemed attractive seen from afar.
A physicist named Ghose has shown Bohm's version of quantum theory does
not work. There are some things not correctly predicted.
Look up Ghose on xxx.lanl.gov
Bob Kolker
Robert Kolker
Arnold wrote:
>
>
> You need to explain why laws which are never correct under
> any circumstances should be taught.
The -kind- of theory that Newton developed is still the prototype of all
workable physical theories, even if some of the details had to be
altered. Newtons method of setting up an empirically testable
mathematically based theory is THE breakthrough. There was nothing like
it before Newton, and all subsequent theories are in the same category
despite the change in details.
Analytic mechanics based on momentum and energy (rather than force) has
mathematical constructs that work in relativistic mechanics and quantum
mechanics. In particular the Hamiltonian and Langrangian approach,
properly adapted works for quantum theory (the Schroedinger equation
solution is a Hamiltonian for example). The principle of least action is
still valid, if one defines action correctly. General Relativity field
equations can be obtained by using the so-called Hilbert action or
Hilbert lagrangian.
Theories come and theories go, but all of modern physics still bears the
mark of Newton. It was once said about Newton, one knows the lion by his
claw.
Bob Kolker
Fred Weiss
"Helen" <GHMoh...@yahoo.com> wrote in message
news:1a8f5fe5.03042...@posting.google.com...
> Rod Nibbe <r...@rknibbe.com> wrote in message
news:<3EA53D6D.9090205@rknibbe
> .com>...
> > So why do
> > *you* think first year physics students should be taught a wrong
> > theory?
>
> Because it is a useful theory for most practical purposes.
Yeah, but that's obviously dumb luck since it's false, right? Just as it's
dumb luck that we can use the theory to get to the moon and back.
Just by way of comparison, since they are both repeatedly mentioned as if
they are relevant to this discussion, why isn't Ptolemy or Caloric taught?
Why aren't phrenology, humours, and Lysenko's theories taught in biology or
medical courses?
The difference is clear. They are false and thus could have no practical
applications.
Fred Weiss
Helen
$1s1.3...@newsfeeds.bigpond.com>...
> You need to explain why laws which are never correct under
> any circumstances should be taught.
I answered that. See my post above.
-- Helen.
Helen
225.42...@posting.google.com>...
> I vaguely recall this topic being done to death some years ago, but
> can you tell me if it is worthwhile to study David Bohm--not the
> mysticism aspect, but the "ontological interpretation of QM"? It
> always seemed attractive seen from afar.
Personally, I don't get much out of it (I am not too much into this
interpretation stuff), but as far as I can understand where you are
coming from I would imagine that you might find it worth your while.
-- Helen.
Fred Weiss
"John Alway" <jwa...@hotmail.com> wrote in message
news:dbb7370e.03042...@posting.google.com...
But don't concede Bob's point that it is therefore "wrong". He has always
been unable to grasp the epistemological point involved here, he doesn't
grasp it now, and apparently he never will
Do your own search on the Internet. Course after course, university after
university, text book after text book continue to teach this "wrong" law to
their engineering and physics students and offer innumerable applications
for it.
Here are just a few examples out of dozens, probably 100's, I could provide
you.
http://www.howstuffworks.com/ejection-seat3.htm
http://www.e-z.net/~ts/physics.htm
http://www4.ncsu.edu/~mowat/H&M_WebSite/SampleReport/report.html
None of these discussions imply *nor need they* that the "Second Law" won't
apply at *very* high velocities and none of them therefore pronounce that
the law is wrong. Because it isn't.
Fred Weiss
Robert Kolker
Fred Weiss wrote:
>
> But don't concede Bob's point that it is therefore "wrong". He has always
> been unable to grasp the epistemological point involved here, he doesn't
> grasp it now, and apparently he never will
Keep in mind that there are degrees of wrongness. The incorrectness of
Newtonian mechanics and gravity did not surface until technology
revealed the flaws. Better telescopes and clocks produced good ephemeri
for mercury. Thompson's experiments with electron beams were off because
the relativistic mass of electrons going at 70,000 miles per second was
not known.
The break came with Einstein's paper on the electrodynamics of moving
bodies.
Bob Kolker
Tom Clarke
> Fred Weiss writes:
> >"Less precise" is not equivalent to "wrong". By that reasoning a straight
> >edge would be "wrong" as compared to an electron microscope. Oh, well, let's
> >throw out all our rulers.
> This is perhaps one of the most important points. There is no "metaphysical
> ruler". There are only means of measurement employed by humans all of which
> are completely accurate even as they are not equally precise.
That is so backwards.
Accuracy implys an absolute standard, whereas precision implies repeatability.
If humans pay attention to what they are doing, applying skill and art, they
can make their measurments repeatable. They can achieve precision.
This is what science is all about, different groups repeating experiments
to provide verification and checking of results.
But there is no absolute accurate standard - well other than reality itself.
In the current discussion Newton checked against the orbit of Mercury
or GPS satellite positions is found in error, but general relativity has so
far never been found to be in error. But this does not imply that
general relativity is correct, that it is the ultimate, absolute
standard.
Tom Clarke
Tom Clarke
> I wrote:
> >> This is perhaps one of the most important points. There is no
> >>"metaphysical ruler". There are only means of measurement
> > employed by humans all ofwhich
> >> are completely accurate even as they are not equally precise.
>
> Tom Clarke writes:
> >That is so backwards.
>
> >Accuracy implys an absolute standard, whereas precision implies
> >repeatability.
>
> But there is no "absolute" standard of measurement.
Except for reality of course, but that is not what we mean. Or by
convention as in the standard meter in Paris (I think they use some number
of wavelengths of red krypton light now, but the idea is that by
convention, human choice, a certain distance has been chosen as the
absolute standard).
> The purpose of measurement is to bring everything within grasp of our
> consciousness, therefore all standards of measurement are units we can pe
> rceive
> or are reducable to units we can perceive.
Isn't this all rather understood? Is there some deep point in this?
Sometimes I think that the object of Objectivism (slight pun left in)
is to debunk religion. In this case statements like the above make
sense. But these sorts of statements tend to go two far if the
result is that known counter-factual scientific theories are made true.
Science doesn't need such statements to debunk religion.
Actually the above is very reminiscent of the Copenhagen interpretation
of quantum mechanics.
> It is the unit of measurement that determines accuracy.
[I think the word is precision]
> ... If I say "this table
> is fifty inches long" that is accurate so long as I correctly use a ruler
> . But
> it's not as precise as, say, a ruler with more demarcations which allows
> me to
> conclude that this table is 50.2 inches. But they are accurate measurements
> relative to the unit of measurement.
So the table is approximately 50 inches long. It is also approximately 50.2
inches long. But it is not true that is 50 inches long, nor is it true tha
t it is
50.2 inches long. I would not use "true" this way. In fact I would be ske
ptical
of a statement such as "it is true that the table is 50.2 inches long". Th
at would
raise for me the warning flag of "... doth protest too much".
> And if you want to make things really simple, I'll even allow that one need
> state a range -- "This table is between 50 and 51 inches." That is compl
> etely
> accurate and there's no two ways around that.
It may be accurate to +/- 1 inch or it may be precise to
within +/-1 inch. Accurate if ruler is traceable back to standard meter etc,
precise if the markings are an inch apart on a ruler of unknown quality.
Tom Clarke
Tom Clarke
> I wrote:
> >> Wrong, by what standard?
>
> Tom Clarke writes:
> >I told you, by sufficiently accurate measurement.
>
> You're confusing precision with accuracy, which is an error.
Yes. You are right. I should have written "precise measurement".
> >> Given the measurement and the means of measurement
> >> Newton used, the only ones he could have used AFAIK, they are exactly cor
> >> rect.
>
> >So we are limited to the measurements Newton had available in using
> >Newton's theory?
>
> Of course not, but in evaluating the truth of his theory it is essential to
> specify the context which includes the standards of measurement, both spa
> cially
> and temporally.
So are we talking abou 2003 or 1687?
> >Then we could certainly never get to the moon using Newton's theory!
> >Are we discussing philosophy or the history of science?
>
> We're discussing the relationship between Newton's theory and reality in
> order
> to highlight the principles of a proper epistemology. Newton's theory is
> true
> in that it correctly describes a particular segment of reality within a c
> ertain
> range of precision.
I guess one can define "true" that way. But as Gordon Sollars says
that does not seem like a very useful definition.
> True, it does not describe every segment of reality, not even every segme
> nt we
> know about. Nor is it as precise as the TOR which happens to encompass those
> segments of reality correctly described in Newton's theory.
And for that reason I would tend to say that Newton's theory is not true,
according to a scientific usage of the word "true".
> And that's just the point -- knowledge is contextual and later knowledge does
> not contradict earlier knowledge, but expands upon it.
If Newton's theory say that a GPS satellite is at 10,000 km and
general relativity says that it is at 10,000.01 km (agreeing with data)
then both of these are true?
How bizarre!
> In this regard, notice
> that Newton is still taught in introductory physics classes -- it isn't w
> rong,
> it's limited.
It's like learning an instrument. You don't learn music theory
until you have mastered some of the basics. You use the approximate
even tempered scale built into the piano even though it is not precisely
harmonically correct.
> >> Are you assuming there's some "metaphysical" ruler by which we define
> >> "precise"? There isn't, you know.
>
> >No, I am not assuming that. But it is now the case that human measurement
> >tools are accurate enough to detect the errors in the Newtonian theory
> >in many cases.
>
> But they aren't errors, they are limits of precision,
They are errors. The satellite is at 10,000.01 km (it really is) whereas
Newtonian theory predicts 10,000.00 km.
> and in cases of bodies
> moving at higher velocities, limits of applicability. Limits aren't
> epistemological disqualifiers.
Your usage of "true" does seem mostly consistent but I find it
not very useful. I say "mostly" because I don't understand at
all how the Objectivist line of reasoning derives a requirement
for an absolute standard from the skeptical stance.
> >And - as several have pointed out - the conceptual basis of the theory that
> >does accurately predict when Newton's theory is wrong is incompatible with
> >the existents assumed in Newton's theory. So unless the universe is some
> >sort of patchwork, Newton up to this point, then General Relativity
> >thereafter,
> >Newton's theory does not correspond to what exists.
>
> We'll get to that.
>
> >> But it's accurate insofar as it describes what experience directly, no?
>
> >Are we talking philsophical matters of principle or matters
> >of what is good enough in everyday life, what is good enough for
> >the cave man?
>
> False dichotomy. "Good enough for everyday life" in this context means
> "accurate", which Newton's theory is as far as everyday life goes.
So where does philosophy come into this discussion?
> >The guy I saw surveying with the back pack GPS this morning was
> >making use of relativity. He probably didn't give it a thought, but
> >without relativity, his apparatus would be lucky to get him in the
> >correct city.
>
> Which goes to show why it's important to constantly expand one's knowledge.
> The point isn't that Newton's theory is true in a context and therefore
> relativity is worthless. The point is, Newton's theory is TRUE in a context
> and thank God, because if it weren't, the moment we discovered the limits of
> relativity we'd have to discard that too. And then how the hell would we
> make
> those GPS work?
I still don't understand what is the problem with saying that
Newton's theory is approximately correct in a certain context.
I really do not see what is superior about "true in a context".
Actually I think it an inferior way of speaking as Newton's theory
_always_ as large or larger compared to experiment than does
general relativity. "Approximately correct" expresses this fact,
but "true" does not.
Tom Clarke
Tom Clarke
That's the spirit!
You cannot be certain of the table being precisely 50.345 inches
but you can be certain that it is imprecisely in some range.
The only certainty is in uncertainty, to try for a pithy statement.
Tom Clarke
Tom Clarke
> > > *you* think first year physics students should be taught a wrong
> > > theory?
> > Because it is a useful theory for most practical purposes.
>
> Yeah, but that's obviously dumb luck since it's false, right?
No it is to be expected. There was a time when Newton's theory was
good enough, just as there was a time when flat earth theory was good
enough and also when crystal sphere theory was good enough.
For some purposes all these are good enough today, even though they
are false under the light of precise enough measurements.
The guy who surveys your plat so you can sell your house doesn't worry
about the curvature of the earth.
They still talk about the "celestial sphere" in astronomy courses as
a way for students to learn the angular relationships involved.
> Just as it's
> dumb luck that we can use the theory to get to the moon and back.
No the moon doesn't move fast enough nor is it in a deep enough
gravity well that the foot or so difference in predictions between
general relativity and Newton's theory make a practical difference.
Now if and when we ever send a probe to a neutron star ....
> Just by way of comparison, since they are both repeatedly mentioned as if
> they are relevant to this discussion, why isn't Ptolemy or Caloric taught?
Hey I already mentioned that. The celestial sphere is taught.
The heat equation dH/dt=-del^2H essentially treats heat as a fluid.
> Why aren't phrenology, humours, and Lysenko's theories taught in biology or
> medical courses?
Because those have no practical uses that I know of. They have been totally
disproven. Or do you know of some context in which phrenology is
has useful applications?
> The difference is clear. They are false and thus could have no practical
> applications.
So we agree that on "they are false".
But "false" and "having practical applications" are not mutually exclusive.
There is a field of study called "folk physics" that investigates
how people think about physics. Their ideas are wrong in the light
of the discoveries of Galileo and followers, but they are still useful
for many everyday tasks. The old ideas about heavy bodies falling faster
and force being required to maintain motion are among these "folk physics"
concepts.
It sounds like Objectivism defines "true" to mean essentially
"having practical applications", but I like to reserve "true" for
the best that human thought has to offer at any particular time,
not for 300 year old theories that while still useful in some
domain have been surpassed.
Tom Clarke
Robert Kolker
Tom Clarke wrote:
> If Newton's theory say that a GPS satellite is at 10,000 km and
> general relativity says that it is at 10,000.01 km (agreeing with data)
> then both of these are true?
> How bizarre!
If we really wanted to be mean to the Iraqis we could have used GPS
aiming in Newtonian mode. The inbound Tomahawks would have been a hudred
meters off the mark.
You distinction between precision and accuracy were on the mark. The
U.S. strikes against Saddam were precise but not accurate. Precission is
getting a good grouping on the target sheet. Accuracy is hitting the V
ring.
Bob Kolker
Helen
@attbi.com>...
> Theories come and theories go, but all of modern physics still bears the
> mark of Newton. It was once said about Newton, one knows the lion by his
> claw.
And it was Jacob Bernoulli who said that, after he saw the solution to
the Brachistochrone problem Newton had submitted anonymously in
response to his challenge. Of course, and in those days in particular,
Newton's style and approach could be recognized by anyone familiar
with the calculus of the time.
-- Helen.
Helen
0.atl.mindspring.net>...
> The difference is clear.
What would you know about that? You don't even know what "Newton's
Theory" is, and I would be suprised if you could explain to me what is
wrong with the caloric theory.
> They are false and thus could have no practical applications.
No, the difference is that these other theories you mentioned are not
useful.
-- Helen.
Don Watkins III
>> But there is no "absolute" standard of measurement.
Tom Clarke writes:
>Except for reality of course, but that is not what we mean.
I hope not, because reality isn't a standard of measurement -- a standard of
measurement is a unit of of some measurable characteristic (e.g., length,
weight, etc.) chosen by a human being to serve a particular purpose. Try doing
that with "reality".
> Or by
>convention as in the standard meter in Paris (I think they use some number
>of wavelengths of red krypton light now, but the idea is that by
>convention, human choice, a certain distance has been chosen as the
>absolute standard).
Well, now you're hedging: of course we can (and should) agree on some standard
of measurement, but that doesn't make it "absolute" -- it makes it merely the
agreed upon standard.
[...]
>> ... If I say "this table
>> is fifty inches long" that is accurate so long as I correctly use a ruler
>> . But
>> it's not as precise as, say, a ruler with more demarcations which allows
>> me to
>> conclude that this table is 50.2 inches. But they are accurate
>measurements
>> relative to the unit of measurement.
>So the table is approximately 50 inches long. It is also approximately 50.2
>inches long. But it is not true that is 50 inches long, nor is it true tha
>t it is
>50.2 inches long. I would not use "true" this way. In fact I would be ske
>ptical
>of a statement such as "it is true that the table is 50.2 inches long". Th
>at would
>
>raise for me the warning flag of "... doth protest too much".
The table is however long it is, of course. Now, if you use a ruler to measure
a table and you get to 50" and there's a little bit left over, you can say the
table is approximately 50". But if there isn't any left over you CAN say it is
exactly 50" -- what grounds would have for saying otherwise? What purpose does
it serve? The limits of a standard of measurement are inherent and that's
acknowledged implicitly -- after all, no one is surprised when an atomic
microscope indicates that maybe the table isn't 50.00000...inches.
The standard of measurement, i.e., the one chosen by the measurer, determines
the standard of accuracy.
This isn't all that radical an idea. After all, if you play basketball, the
entire ball has to go through the hoop to score a point...not just a few
molecules. The rules of the game determine what counts as a point, just as the
standard of measurement determines what qualifies as an accurate measurement.
Thus the question I've raised: accurate, by what standard?
You say reality, but that's no good for reasons I've outlined above. By the
standards of a more precise measurement? That's irrelevant.
Now, I should add that you can't arbitrarily select a standard of measurement.
A physicist can't use a meter stick to measure atoms and a rocket scientist
can't use a microscope to study trajectories. The "subject" determines the
range of appropriate standards of measurement. The standard of measurement
determines accuracy. Precision is relevant when precision matters.
Don Watkins
http://www.don-watkins.com
http://donwatkins.blogspot.com
Don Watkins III
Just to point out that I'm not pulling my definitions out of a hat, here's from
dictionary.com:
Accurate:
2. Deviating only slightly or within acceptable limits from a standard.
3. Capable of providing a correct reading or measurement: an accurate scale.
Precision:
1.The state or quality of being precise; exactness.
2(b). The number of significant digits to which a value has been reliably
measured.
There were other definitions, of course, and my point isn't that I have the One
True definition, but that I'm in line with general usage.
Don Watkins III
> > Of course not, but in evaluating the truth of his theory it is essential to
> > specify the context which includes the standards of measurement, both spa
> > cially
> > and temporally.
Tom Clarke writes:
> So are we talking abou 2003 or 1687?
It doesn't matter, actually, except that the context for which we know
Newton's theory to hold is wider than the one Newton knew about, plus
we know it's limits which is a big plus. But within those limits we
have the philosophical point: Newton's theory conforms to the facts.
That is both necessary and sufficient to establish its truth value --
that it conforms to the facts within a context.
> > We're discussing the relationship between Newton's theory and reality in
> > order
> > to highlight the principles of a proper epistemology. Newton's theory is
> > true
> > in that it correctly describes a particular segment of reality within a c
> > ertain
> > range of precision.
> I guess one can define "true" that way. But as Gordon Sollars says
> that does not seem like a very useful definition.
That's right -- he prefers a definition of truth such that we can
never know when anything is true. How that's suppossed to be more
"useful" (whatever that means) I'm not sure.
Objectivists use truth very specifically -- as the concept that
denotes one's grasp of some fact. Unless you maintain that's
impossible, which of course it isn't, such a definition is on firm
ground. But that still leaves the question, what does it mean to
grasp facts? How does one go about it? To answer those questions
context must play a role because it's a fact fundamental to human
consciousness: we only know so much.
> > True, it does not describe every segment of reality, not even every segme
> > nt we
> > know about. Nor is it as precise as the TOR which happens to encompass
> > those
> > segments of reality correctly described in Newton's theory.
> And for that reason I would tend to say that Newton's theory is not true,
> according to a scientific usage of the word "true".
Okay, but then you're left with the conclusion that nothing is true,
and if it is you can't know it, so what the hell, let's all flap our
arms and fly because maybe we can. As I've pointed out to Gordon,
once you accept the premise that we can't know what's true then you
have to accept the flip-side -- we can never know what's false. This
fact destroys the so-called scientific alternative of Popperism
because it shows it for what it is -- epistemological bankruptcy.
> > And that's just the point -- knowledge is contextual and later knowledg
> > e does
> > not contradict earlier knowledge, but expands upon it.
> If Newton's theory say that a GPS satellite is at 10,000 km and
> general relativity says that it is at 10,000.01 km (agreeing with data)
> then both of these are true?
> How bizarre!
I've already agreed that there are limits to Newton's theory, one of
which might very well be GPS. In the case of GPS, I'm going to hazard
a guess that these small differences in measurement are significant,
yes? Well, then you're only proving my point -- precision matters
when it matters and when it matters this marks a limit of a theory
that does not give you that kind of precision.
There is another point of clarification, here: there might also be
cases where Newton's theory isn't accurate. Say, it says the planet
should be "here" but it's actually "there". This, of course, is
another instance of a limitation on Newton's theory, but we're still
left with a true theory with limits...not a bad place to be given the
alternative.
> > In this regard, notice
> > that Newton is still taught in introductory physics classes -- it isn't w
> > rong,
> > it's limited.
> It's like learning an instrument. You don't learn music theory
> until you have mastered some of the basics. You use the approximate
> even tempered scale built into the piano even though it is not precisely
> harmonically correct.
Good metaphor. Still, there's no dispute that Newton's theory isn't
as precise in some places as relativity.
> > But they aren't errors, they are limits of precision,
> They are errors. The satellite is at 10,000.01 km (it really is) whereas
> Newtonian theory predicts 10,000.00 km.
Back to my previous point -- to the extent that the limits in
precision result in inaccuracy, Newton's theory doesn't apply.
> > and in cases of bodies
> > moving at higher velocities, limits of applicability. Limits aren't
> > epistemological disqualifiers.
> Your usage of "true" does seem mostly consistent but I find it
> not very useful. I say "mostly" because I don't understand at
> all how the Objectivist line of reasoning derives a requirement
> for an absolute standard from the skeptical stance.
I'm not sure I know what you're saying -- that it doesn't refute
skepticism, or that it is wrong for claiming skepticism makes
omniscience the standard of knowledge...or maybe something else.
> > >Are we talking philsophical matters of principle or matters
> > >of what is good enough in everyday life, what is good enough for
> > >the cave man?
> > False dichotomy. "Good enough for everyday life" in this context means
> > "accurate", which Newton's theory is as far as everyday life goes.
> So where does philosophy come into this discussion?
Where has it left the discussion?
> > Which goes to show why it's important to constantly expand one's knowledge.
> > The point isn't that Newton's theory is true in a context and therefore
> > relativity is worthless. The point is, Newton's theory is TRUE in a co
> > ntext
> > and thank God, because if it weren't, the moment we discovered the limi
> > ts of
> > relativity we'd have to discard that too. And then how the hell would we
> > make
> > those GPS work?
> I still don't understand what is the problem with saying that
> Newton's theory is approximately correct in a certain context.
> I really do not see what is superior about "true in a context".
> Actually I think it an inferior way of speaking as Newton's theory
> _always_ as large or larger compared to experiment than does
> general relativity. "Approximately correct" expresses this fact,
> but "true" does not.
I actually don't have a problem with "approximately correct" as I
think you're using it. What I do have a problem with is the idea that
therefore Newton's theory is false and we can never know anything,
which is itself false. Besides, by the standard you invoke,
relativity is only approximate, but maybe more approximate which
leaves us no better off because it still requires a qualifier.
To put it simply, if human beings can grasp facts, and if they do so
in a context, then truth is contextual, whether you find that "useful"
or not.
Robert Kolker
Don Watkins III wrote:
>
> Okay, but then you're left with the conclusion that nothing is true,
> and if it is you can't know it, so what the hell, let's all flap our
> arms and fly because maybe we can.
The best one can say of any theory is --- so far, so good. That has
always been the case and it will always be the case.
As I've pointed out to Gordon,
> once you accept the premise that we can't know what's true then you
> have to accept the flip-side -- we can never know what's false. This
> fact destroys the so-called scientific alternative of Popperism
> because it shows it for what it is -- epistemological bankruptcy.
Popper was right on the money. If a theory is not potentially breakable,
it is worthless. Every experiment, especially crucial experiments are an
opportunity to break the theory. Experiments should be designed not with
a mind to be nice to the theory, but to put the theory on the rack to
see if it will come apart at the joints.
Soft ball experiments are really experiments at all, they are
demonstrations.
Bob Kolker
Robert Kolker
Robert Kolker wrote:
> Soft ball experiments are really
not
experiments at all, they are
> demonstrations.
Sorry about that.
Bob Kolker
Helen
219.1e...@posting.google.com>...
> That is both necessary and sufficient to establish its truth value --
> that it conforms to the facts within a context.
Whatever the term "context" may mean, eh?
> > And for that reason I would tend to say that Newton's theory is not true,
> > according to a scientific usage of the word "true".
Scientists do not use the term "true" when they speak of
non-tautological theories in a rigorous manner. The concept of truth
is completely useless for any practical, scientific purpose. As a
scientist, I could hardly care less if a theory is "true". There is no
way to know if that is the case, at least not without mutilating the
concept of "truth" to end up with the kind of idiocy you have in
"objectivism". As I said before, it is only the kind of weak minds
that are suceptible to quasi-religious nonsense like "objectivism"
that need "truth" in order to be able to face the world out there.
> Okay, but then you're left with the conclusion that nothing is true,
> and if it is you can't know it, so what the hell, let's all flap our
> arms and fly because maybe we can.
Nonsense. Just because you adhere to a hopelessly muddled and mentally
debilitating quasi-religion does not mean everybody's brain has rotted
to such a degree. As proof of what I am saying, observe that very few
of us "flap [their] arms and fly because maybe we can".
> As I've pointed out to Gordon,
> once you accept the premise that we can't know what's true then you
> have to accept the flip-side -- we can never know what's false.
That, of course, is complete nonsense, too.
-- Helen.
Gordon Sollars
@aol.com says...
> It doesn't matter, actually, except that the context for which we know
> Newton's theory to hold is wider than the one Newton knew about, plus
> we know it's limits which is a big plus. But within those limits we
> have the philosophical point: Newton's theory conforms to the facts.
But not with a causal explanation. The cause it posits - a force with
certain characteristics - does not exist.
....
> That's right -- he prefers a definition of truth such that we can
> never know when anything is true.
Let's be precise: We cannot be /certain/. And it would be wrong to hold
knowledge hostage to certainty, because their is no method that gives
(epistemic) certainty.
....
> As I've pointed out to Gordon,
> once you accept the premise that we can't know what's true then you
> have to accept the flip-side -- we can never know what's false.
No: We can never be /certain/. See above.
> This
> fact destroys the so-called scientific alternative of Popperism
> because it shows it for what it is -- epistemological bankruptcy.
It shows that knowledge does not require certainty - and a darn good
thing, too.
....
> There is another point of clarification, here: there might also be
> cases where Newton's theory isn't accurate. Say, it says the planet
> should be "here" but it's actually "there".
And /why/ does it do that? Because the force it posits does not exist.
If it /did/ exist, the planet would be right there where Newton said it
should be.
> This, of course, is
> another instance of a limitation on Newton's theory, but we're still
> left with a true theory with limits...not a bad place to be given the
> alternative.
Spoken like a true instrumentalist.
--
Gordon Sollars
gsol...@pobox.com
Tom Clarke
....
> > So are we talking abou 2003 or 1687?
> It doesn't matter, actually, except that the context for which we know
> Newton's theory to hold is wider than the one Newton knew about, plus
> we know it's limits which is a big plus.
But as I keep saying again and again. Scientifically speaking
Newton's theory does not hold. We now know it to be wrong so
it holds in a far narrower context than it did in 1687!
> But within those limits we
> have the philosophical point: Newton's theory conforms to the facts.
It conforms approximately to the facts, if that is good enough
for you. But if you are after precision ...
> That is both necessary and sufficient to establish its truth value --
> that it conforms to the facts within a context.
Will conforms _approximately_ to facts within a context do?
> > > ....Newton's theory is
> > > true
> > > in that it correctly describes a particular segment of reality within a c
> > > ertain
> > > range of precision.
> > I guess one can define "true" that way. But as Gordon Sollars says
> > that does not seem like a very useful definition.
>
> That's right -- he prefers a definition of truth such that we can
> never know when anything is true. How that's suppossed to be more
> "useful" (whatever that means) I'm not sure.
It's not useful when talking to scientists, I can tell you.
This should be clear from these threads.
> Objectivists use truth very specifically -- as the concept that
> denotes one's grasp of some fact. Unless you maintain that's
> impossible, which of course it isn't, such a definition is on firm
> ground.
Oh it seems to work. I haven't heard of a rash of Objectivists getting
run over by trucks or whatever, but I doesn't help communicate.
> But that still leaves the question, what does it mean to
> grasp facts? How does one go about it? To answer those questions
> context must play a role because it's a fact fundamental to human
> consciousness: we only know so much.
Well of course.
But it occurs to me, were Objectivists back in 1980 or so certain
that smoking tobacco did not contribute to cancer?
> > > .... Nor is it as precise as the TOR which happens to encompass
> > > those
> > > segments of reality correctly described in Newton's theory.
> > And for that reason I would tend to say that Newton's theory is not true,
> > according to a scientific usage of the word "true".
>
> Okay, but then you're left with the conclusion that nothing is true,
> and if it is you can't know it, so what the hell, let's all flap our
> arms and fly because maybe we can.
Not that nothing is true, but that human beings cannot have certain
true knowledge.
It seems to me that Objectivists agree with this and then just redefine
"true" so that then can have certain true(Objectivist) knowledge.
> As I've pointed out to Gordon,
> once you accept the premise that we can't know what's true then you
> have to accept the flip-side -- we can never know what's false.
You work with the odds.
> This
> fact destroys the so-called scientific alternative of Popperism
> because it shows it for what it is -- epistemological bankruptcy.
There you go, using loaded terms like "bankruptcy".
I could say that Objectivism is a philosophy based on a number
of equivocations from my point of view. Let's keep it above the
belt.
Truth be told I am not so much against certainty as I am
against authority. I always question authority. I am really
certain only of what I know personally or can personally trace
to reliable sources I consider reliable.
.....
> > If Newton's theory say that a GPS satellite is at 10,000 km and
> > general relativity says that it is at 10,000.01 km (agreeing with data)
> > then both of these are true?
> > How bizarre!
> I've already agreed that there are limits to Newton's theory, one of
> which might very well be GPS. In the case of GPS, I'm going to hazard
> a guess that these small differences in measurement are significant,
> yes?
Yes. Admittedly I picked 10 meters out of a hat for the difference,
but I do know that general relativity must be used with the GPS
system.
> Well, then you're only proving my point -- precision matters
> when it matters and when it matters this marks a limit of a theory
> that does not give you that kind of precision.
I still don't get your point.
By my standard of personal knowledge I know, I am certain, that
Newton's theory will always give a different answer from GR, and
that an measurment of sufficient precision will show that
GR is closer to what is really there in the universe.
> There is another point of clarification, here: there might also be
> cases where Newton's theory isn't accurate.
I'll say it one more time. It is never accurate. It can be good
enough.
>Say, it says the planet
> should be "here" but it's actually "there". This, of course, is
> another instance of a limitation on Newton's theory, but we're still
> left with a true theory with limits...not a bad place to be given the
> alternative.
I really find that that usage of "true" is not useful.
....
> > It's like learning an instrument. You don't learn music theory
> > until you have mastered some of the basics. You use the approximate
> > even tempered scale built into the piano even though it is not precisely
> > harmonically correct.
> Good metaphor. Still, there's no dispute that Newton's theory isn't
> as precise in some places as relativity.
In all places. ALL ALL ALL. How many times do I have to write it?
> > > But they aren't errors, they are limits of precision,
> > They are errors. The satellite is at 10,000.01 km (it really is) whereas
> > Newtonian theory predicts 10,000.00 km.
> Back to my previous point -- to the extent that the limits in
> precision result in inaccuracy, Newton's theory doesn't apply.
I just do not understand why one would want to think this way.
To me it seems so muddleheaded.
Its true here but its not true there, depends on how accurate
the measurements are... My way of thinking is so much clearer.
It is false, but approximately correct in some domains.
.....
> > Your usage of "true" does seem mostly consistent but I find it
> > not very useful. I say "mostly" because I don't understand at
> > all how the Objectivist line of reasoning derives a requirement
> > for an absolute standard from the skeptical stance.
> I'm not sure I know what you're saying -- that it doesn't refute
> skepticism, or that it is wrong for claiming skepticism makes
> omniscience the standard of knowledge...or maybe something else.
It is wrong for claiming that skepticism makes omniscience the
standard of knowledge. That is a good way of putting what I am
saying.
....
> > > False dichotomy. "Good enough for everyday life" in this context means
> > > "accurate", which Newton's theory is as far as everyday life goes.
>
> > So where does philosophy come into this discussion?
> Where has it left the discussion?
When good enough for "government work" entered it.
.....
> > I still don't understand what is the problem with saying that
> > Newton's theory is approximately correct in a certain context.
> > I really do not see what is superior about "true in a context".
> > Actually I think it an inferior way of speaking as Newton's theory
> > _always_ as large or larger compared to experiment than does
> > general relativity. "Approximately correct" expresses this fact,
> > but "true" does not.
> I actually don't have a problem with "approximately correct" as I
> think you're using it. What I do have a problem with is the idea that
> therefore Newton's theory is false
STOP. That is a far as I go.
> and we can never know anything,
I disagree that you can get that conclusion from saying that Newton
is false or from skepticism for that matter.
> which is itself false. Besides, by the standard you invoke,
> relativity is only approximate,
I expect that it is. After all human knowledge is limited.
You agree right? To claim otherwise would be to claim that in
relativity humans had attained omniscience which is impossible.
Don't you agree?
> but maybe more approximate which
> leaves us no better off because it still requires a qualifier.
We don't know the quantifier. Someday it will be found. Or not.
But the search goes on. Science is always looking to increase
precision and range of applicability of theory and experiment.
> To put it simply, if human beings can grasp facts, and if they do so
> in a context, then truth is contextual, whether you find that "useful"
> or not.
I just do not find that Objectivism expresses this in a way that
is useful and not confusing.
Tom Clarke
John Alway
@attbi.com>...
A thumb up on that!
Few things are more useful to software design than math, so it
probably gave you a solid foundation.
...John
Gordon Sollars
tcl...@ist.ucf.edu says...
....
> Truth be told I am not so much against certainty as I am
> against authority.
Then you are ready for an evolutionary epistemology, the only non-
authoritarian kind.
--
Gordon Sollars
gsol...@pobox.com
John Alway
0.atl.mindspring.net>...
[...]
> > Actually, I knew this. I guess I don't use it, so I had forgotten.
> > Newtonian mechanics work very well for relatively, no pun intended,
> > low velocities, but lose accuracy for *very* high velocities.
> But don't concede Bob's point that it is therefore "wrong". He has always
> been unable to grasp the epistemological point involved here, he doesn't
> grasp it now, and apparently he never will
> Do your own search on the Internet. Course after course, university after
> university, text book after text book continue to teach this "wrong" law to
> their engineering and physics students and offer innumerable applications
> for it.
I agree. I was taught it myself. This is because it works for
the vast majority of the cases. You do, however, when dealing with
things like satellite communications, have to use Einstein's work.
Still, in my book, Newton's method of doing science is *the*
standard.
...John
Arnold
"Tom Clarke" <tcl...@ist.ucf.edu> wrote in message
news:ab311d64.03042...@posting.google.com...
You missed where I said "beyond all doubt". There is not a
hint of uncertainty there. The only thing to point out, is
that one can be certain within limits. Those limits are the
context. Hence Don was accurate despite inaccuracies being
involved (the range).
--
Arnold
Arnold
All I have seen is from Bob, who pays rightly tribute to
Newton, (and you agreed). Telling me all the good things
Newton did, does not explain why the _specific_ "wrong"_
theories are taught. Does the class go something like
this-----"Today we are going to learn about a guy called
Newton who was proved to be wrong, and there is no
situation where he is correct. The only reason we study him
is because he is a good approximation at low mass and
velocity. Tomorrow we study astrology."?
Acar
"Don Matt" <dma...@hotmail.com> wrote in message
news:82f24994.03042...@posting.google.com...
> > > There seems to be an idea that in line with the Objectivist
> > > concept of context Newtonian (gravity) theory is correct up to
> > > a point and then it stops being correct.
> >
> > OT: This is a good example of contextual truth as a pragmatic device.
Truth
> > is the best that we can do. Correspondence becomes non-contradiction,
IOW
> > coherence.
>
> I haven't understood you.
AIUI Objectivists believe that when you have an abundance of evidence
without contradiction you may become satisfied of the truth of the matter.
If future evidence makes it necessary to modify expand or replace the
concept, you may still say that it was true in the old context.
> Do you mean that there is a truth only to a
> specific context and therefore an universal truth is an impossible
> goal? I think that if yes it would mean that the positivist (or
> Kolkerism, if you desire) claim that only what can be tested is truth.
> Or with other words: what you have not tested is only an assumption.
..
..
..
..
..
..
..
Fred Weiss
"Gordon Sollars" <gsol...@pobox.com> wrote in message
news:MPG.19111c914...@news.optonline.net...
>> Newton's theory conforms to the facts.
>
> But not with a causal explanation. The cause it posits - a force with
> certain characteristics - does not exist.
What "cause" does it posit? You know you keep repeating this like a mantra
as if its constant repetition will render it true. I'm largely ignorant of
physics but as far as I can tell Newton never made any claims about what
*causes* bodily motion. He just discovered that it follows certain
mathematical laws. Which in fact it does. Period. That's why by applying
Newton's Laws we can do some astounding things like get to the moon and
back.
> ....
> > That's right -- he prefers a definition of truth such that we can
> > never know when anything is true.
>
> Let's be precise:
Be precise, huh? Gee I wonder what that could mean if not "get to the truth"
which he is denying we can do.
> We cannot be /certain/.
Cannot, huh? Gee I wonder what is true about the world which Gordon knows
which leads him to think we can know nothing is true.
And it would be wrong to hold
> knowledge hostage to certainty, because their is no method that gives
> (epistemic) certainty.
No method, huh? Gee I wonder what standard of method is being required here
and why the truth of it is assumed in the very process of denying that any
such truth is possible.
Fred Weiss
Fred Weiss
I'm largely ignorant of physics but would I be safe in assuming that you
could precisely define what is different about satellite communications
which makes Newtons Law's inapplicable vs. all the other cases.
Am I also safe in assuming that in many of those other case, though perhaps
it might be, no one would use Einstein's work? Incidentally is that the case
that Einstein could be used in all those cases?
What's going through my mind is something like maybe there is some
cumbersome way to use an electronic microscope to measure the length of a
dining table but you'd have to be out of your mind to use it for that unless
for some highly unusual reason you needed extraordinary precision in your
measurements. On the other hand you simply couldn't use a straight edge to
measure certain things like sub-atomic particles (which doesn't invalidate
or make rulers "wrong"). Do you see what I'm trying to get at here?
Fred Weiss
Tom Clarke
> I wrote:
> >> But there is no "absolute" standard of measurement.
>
> Tom Clarke writes:
> >Except for reality of course, but that is not what we mean.
>
> I hope not, because reality isn't a standard of measurement -- a standard of
> measurement is a unit of of some measurable characteristic (e.g., length,
> weight, etc.) chosen by a human being to serve a particular purpose. Try
> doing
> that with "reality".
I was thinking of downplaying the "measurement" part and emphasizing
the "standard".
> > Or by
> >convention as in the standard meter in Paris ....
>
> Well, now you're hedging: of course we can (and should) agree on some sta
> ndard
> of measurement, but that doesn't make it "absolute" -- it makes it merely the
> agreed upon standard.
What term would you apply to an agreed upon standard like the standard meter?
.... [regarding measuring a table]
> >So the table is approximately 50 inches long. It is also approximately 50.2
> >inches long. But it is not true that is 50 inches long, nor is it true that
> >it is 50.2 inches long. I would not use "true" this way. ....
>
> The table is however long it is, of course.
It is however long it is in reality.
> Now, if you use a ruler to measure
> a table and you get to 50" and there's a little bit left over, you can sa
> y the
> table is approximately 50". But if there isn't any left over you CAN say
> it is
> exactly 50" -- what grounds would have for saying otherwise?
There is the question of how good the ruler is, how good my eye is etc.etc
All of which are componenets of the inability of humans to measure with
infinite precision.
> What purpose does it serve?
Being as precise in speaking as possible, especially in the philosophical c
ontext.
> The limits of a standard of measurement are inherent
They are not inherent. They can be reduced by work and attention to
detail.
> and that's
> acknowledged implicitly -- after all, no one is surprised when an atomic
> microscope indicates that maybe the table isn't 50.00000...inches.
What's this infatuation with atomic microscopes? Weiss mentioned one too.
The appropriate instrument for high precsions would be an interferometer.
Since the meter is now defined by a wavelength of light, this automatically
results in comparison to the human agreed "absolute" standard.
> The standard of measurement, i.e., the one chosen by the measurer, determines
> the standard of accuracy.
In science/eng the convention is that the number of decimal places gives the
precision. 50 means 50 inches +/- 2 or 3. 50.0 would mean that the
precision is +/- .2 or so, 50.00 would indicate +/- .02 etc.
> This isn't all that radical an idea. After all, if you play basketball, the
> entire ball has to go through the hoop to score a point...not just a few
> molecules.
That analogy goes over my head.
When you sit an Objectivist down and find out what they mean by
certainty(o) you realize it is not certainty(english) or even certainty(sci
ence)
and is more like have-no-reason-to-doubt(english). A good concept
but I do find the funny terminology confusing.
.....
> Thus the question I've raised: accurate, by what standard?
>
> You say reality, but that's no good for reasons I've outlined above. By the
> standards of a more precise measurement? That's irrelevant.
The title of this thread refers to a scientific theory so I guess the standards
should be those of science. A theory is true if it has not been falsified.
Newton's theory has made false predictions so it is not
true by the standards of science. Is this what you mean?
> Now, I should add that you can't arbitrarily select a standard of measure
> ment.
> A physicist can't use a meter stick to measure atoms and a rocket scientist
> can't use a microscope to study trajectories. The "subject" determines the
> range of appropriate standards of measurement. The standard of measurement
> determines accuracy. Precision is relevant when precision matters.
Practicioners of science say Newton's theory has failed the test of
being a true(science) scientific theory. They determined this by standards of
scientific precision. I guess you can say Newton's theory is
true(Objectivism) but then you will have a hard time talking to scientists
and vice versa.
Tom Clarke
Tom Clarke
> Tom:
>
> Just to point out that I'm not pulling my definitions out of a hat, here'
> s from
> dictionary.com:
>
> Accurate:
>
> 2. Deviating only slightly or within acceptable limits from a standard.
> 3. Capable of providing a correct reading or measurement: an accurate scale.
I don't think we disagree about this. We may still
disagree about what the broader implications are.
> Precision:
>
> 1.The state or quality of being precise; exactness.
> 2(b). The number of significant digits to which a value has been reliably
> measured.
2b is the scientific/engineering usage I just finished writing about.
> There were other definitions, of course, and my point isn't that I have t
> he One
> True definition, but that I'm in line with general usage.
The orbit of Mercury precesses relative to the coordinate system defined
by the fixed stars at 88 seconds of arc/century. So that is the
precision required to determine that Newton's theory makes counter
factual predictions since Newton's theory cannot explain this.
In the past, deviations of this nature in the orbit of Uranus led to the
discovery of Neptune by predicting the approximate location of where
another planet must be to produce the perturbations in Uranus' orbit.
People searched for another planet, it would have been called
"Vulcan" sunward of Mercury but none was found. Eventually Einstein
formulated a relativistic theory of gravity that did explain the 88 sec/century
to within measurment precision.
So far Einstein's theory has survived every test thrown at it. It has now
been checked to a precsion of many decimal places [lurkers help
me out, I can't find the exact number easilty 10?]
Tom Clarke
Helen
$1s1.3...@newsfeeds.bigpond.com>...
> All I have seen is from Bob,
If you search for "Because it is a useful theory for most practical
purposes" and "Helen" on Google, you should see the post I am
referring to.
-- Helen.
Tom Clarke
> ... Does the class go something like
> this-----"Today we are going to learn about a guy called
> Newton who was proved to be wrong, and there is no
> situation where he is correct. The only reason we study him
> is because he is a good approximation at low mass and
> velocity. Tomorrow we study astrology."?
Leave off the bit about astrology and add
"and also because it is conceptually easier than the
more advanced theory of relativity you will learn about
next month" and you might have something a scrupulously
honest physics professor might say.
Consider studying geography. The globe is the most
accurate way to depict the earth's surface.
Nevertheless Mercator projection maps are used in
teaching despite their gross distortions.
Tom Clarke
Don Watkins III
>> As I've pointed out to Gordon,
>> once you accept the premise that we can't know what's true then you
>> have to accept the flip-side -- we can never know what's false. This
>> fact destroys the so-called scientific alternative of Popperism
>> because it shows it for what it is -- epistemological bankruptcy.
Bob Kolker writes:
>Popper was right on the money. If a theory is not potentially breakable,
>it is worthless. Every experiment, especially crucial experiments are an
>opportunity to break the theory. Experiments should be designed not with
>a mind to be nice to the theory, but to put the theory on the rack to
>see if it will come apart at the joints.
>Soft ball experiments are really experiments at all, they are
>demonstrations.
I don't disagree with this at all. The point I was making was this: if you
can't know that a theory is true you can't know it's false. After all, just as
you might have made an error when confirming it you might have made an error in
refuting it.
Unless you have a specific reason to doubt, including lack of evidence, missing
evidence, or something along those lines, doubt is epistemologically invalid.
In science, there is what I would call "edge doubt". That is, even for
well-tested true theories like relativity it is valid to test it under as many
circumstances and in as many ways as you can to determine its limits. IOW --
there is always doubt, not necessarily about the validity of a theory, but
about limits of a valid theory.
This is why, even for a theory as well-tested as Newton's, it was valid to keep
trying to "break" it -- to determine its limits, which we did with great
success, leading to a more expansive and more precise theory.
Fred Weiss
"Arnold" <arnold_br...@hotmail.com> wrote in message
news:N3Lpa.21337$1s1.3...@newsfeeds.bigpond.com...
>....Telling me all the good things
> Newton did, does not explain why the _specific_ "wrong"_
> theories are taught. Does the class go something like
> this-----"Today we are going to learn about a guy called
> Newton who was proved to be wrong, and there is no
> situation where he is correct. The only reason we study him
> is because he is a good approximation at low mass and
> velocity. Tomorrow we study astrology."?
Very funny.
Why not astrology? Apparently to some of our opponents Newton isn't much
better than astrology. Astrology is also sometimes correct by coincedence
which I gather must also be the case with Newton since it seems also to be
sometimes correct even though it's false and the "cause" it falsely
attributes to the phenomena it incorrectly measures really doesn't exist.
Oh, and did you notice? Helen doesn't care about any of this since truth
doesn't apply to science. Which is equivalent to saying "who cares whether
what we believe corresponds to reality or not". But then it's no surprise
she thinks that since I've always had the impression she resides in an
alternate universe of her own bizarre imagining.
Fred Weiss
Fred Weiss
"Acar" <g...@d-g-s.com> wrote in message
news:QzLpa.138458$JI.34...@twister.neo.rr.com...
> Truth
> > > is the best that we can do. Correspondence becomes non-contradiction,
> IOW
> > > coherence.
> >
> AIUI Objectivists believe that when you have an abundance of evidence
> without contradiction you may become satisfied of the truth of the matter.
> If future evidence makes it necessary to modify expand or replace the
> concept, you may still say that it was true in the old context.
No, it's simply true in that context - then and now. That however is not
just mere coherence, as important as coherence may be. It is a statement of
fact about reality.
Incidentally, *everything* is true in some context. It is not possible to be
non-contextually true, i.e. "just true" without reference to some specified
time, place, and condition. (The exception is axioms which are necessarily
true of all times and places and all knowledge).
But this is easy stuff that even you understand. Right, Acorn?
Yeah, right.
Fred Weiss
Gordon Sollars
pape...@ix.netcom.com says...
>
> "Gordon Sollars" <gsol...@pobox.com> wrote in message
> news:MPG.19111c914...@news.optonline.net...
>
> >> Newton's theory conforms to the facts.
> >
> > But not with a causal explanation. The cause it posits - a force with
> > certain characteristics - does not exist.
>
> What "cause" does it posit?
An instantaneous force that obeys an inverse-square law. I had just
told you above. Do you really read my posts before you reply or not?
> I'm largely ignorant of
> physics but as far as I can tell Newton never made any claims about what
> *causes* bodily motion.
His theory says that it is caused by an instantaneous force that obeys
an inverse-square law. That is, if you interpret the theory as making a
claim about reality.
> He just discovered that it follows certain
> mathematical laws. Which in fact it does. Period.
Almost does. Period.
> That's why by applying
> Newton's Laws we can do some astounding things like get to the moon and
> back.
Yes, they are very good for that.
....
> > Let's be precise:
>
> Be precise, huh? Gee I wonder what that could mean if not "get to the truth"
> which he is denying we can do.
I have never denied that we can get to the truth. You remain confused
no matter how much we go over this.
> > We cannot be /certain/.
>
> Cannot, huh? Gee I wonder what is true about the world which Gordon knows
> which leads him to think we can know nothing is true.
But I have never said we know that "nothing is true".
> And it would be wrong to hold
> > knowledge hostage to certainty, because their is no method that gives
> > (epistemic) certainty.
>
> No method, huh? Gee I wonder what standard of method is being required here
The standard of certainty of course; that is what the method is supposed
to provide.
--
Gordon Sollars
gsol...@pobox.com
Fred Weiss
"Tom Clarke" <tcl...@ist.ucf.edu> wrote in message
news:ab311d64.03042...@posting.google.com...
> The only certainty is in uncertainty, to try for a pithy statement.
No exceptions, huh?
Have you...err....examined everything in the universe and every bit of
knowledge and found this out?
Also I'm curious what method did you use to come to this conclusion and why
do you think that's the correct method?
Fred Weiss
Don Watkins III
>Incidentally, *everything* is true in some context. It is not possible to be
>non-contextually true
Be careful -- what I think you meant to say is that everything THAT IS TRUE is
true in some context. Fortunately, the context (!) of your statement makes
that clear, but I wouldn't be surprised if someone jumped on it.
puppe...@hotmail.com
ttbi.com>...
[snip]
> And remember, the
> Best is the Enemy of the Good Enough.
I think the actual phrase you want there is "the perfect is
the enemy of the good." But, whatever...
Socks
puppe...@hotmail.com
.1c51...@posting.google.com>...
[snip]
> According to general relativity, objects fall toward the earth because
> the space-time near the earth is curved. This curvature is about
> 1/light-year, or analagous to a circle of radius 6 trillion miles.
>
> The ratio of the length of the path over which an object falls
> to the radius of curvature would then provide an estimate of the
> fractional error in Newtonian theory.
That's not going to work. For one thing, it's going to depend
quite strongly on the relative velocities involved.
Socks
Robert Kolker
Arnold wrote:
>
>
> All I have seen is from Bob, who pays rightly tribute to
> Newton, (and you agreed). Telling me all the good things
> Newton did, does not explain why the _specific_ "wrong"_
> theories are taught.
Some of the mathematical constructs that arose from analytical
mechanics, are still used. The Least Action Principle for example. It
was Newton's force based mechanics that lead to the development of
energy based mechanics. Newton broke the trail.
> Does the class go something like
> this-----"Today we are going to learn about a guy called
> Newton who was proved to be wrong, and there is no
> situation where he is correct. The only reason we study him
> is because he is a good approximation at low mass and
> velocity. Tomorrow we study astrology."?
In addition to a specific cluster of theories, Newton invented an
-approach- to understanding the world, which is still as good today, as
it was when he formulated it. While the plots may change, as necessity
dictates, Newton taught us how to write the plays.
Bob Kolker
Don Watkins III
> > It doesn't matter, actually, except that the context for which we know
> > Newton's theory to hold is wider than the one Newton knew about, plus
> > we know it's limits which is a big plus.
Tom Clarke writes:
> But as I keep saying again and again. Scientifically speaking
> Newton's theory does not hold. We now know it to be wrong so
> it holds in a far narrower context than it did in 1687!
This is mistaken. In 1687 it was true only of what we knew then which
is hardly as much as we know now. Only if you assumed it held for
that which was not known in 1687, which would be an error, would your
above statement be, um, true.
> > But within those limits we
> > have the philosophical point: Newton's theory conforms to the facts.
> It conforms approximately to the facts, if that is good enough
> for you. But if you are after precision ...
Of course I'm for precision when precision is desirable, which is why
I don't demand GPS function on the basis of Newtonian physics. But
just because you can't time Olympic swimmers with a pocket watch
doesn't make the pocket watch invalid.
> > That is both necessary and sufficient to establish its truth value --
> > that it conforms to the facts within a context.
> Will conforms _approximately_ to facts within a context do?
No, because the context includes the means of measurement, including
its limits of precision.
> > That's right -- he prefers a definition of truth such that we can
> > never know when anything is true. How that's suppossed to be more
> > "useful" (whatever that means) I'm not sure.
> It's not useful when talking to scientists, I can tell you.
> This should be clear from these threads.
But the point isn't a scientific one -- it's philosophical one. I'm
merely using the science example to highlight a philosophical point
about the nature of epistemological principles.
> > Objectivists use truth very specifically -- as the concept that
> > denotes one's grasp of some fact. Unless you maintain that's
> > impossible, which of course it isn't, such a definition is on firm
> > ground.
> Oh it seems to work. I haven't heard of a rash of Objectivists getting
> run over by trucks or whatever, but I doesn't help communicate.
Well, even if that were the case, it's more important to hold valid
concepts clearly than it is to communicate easily.
> > But that still leaves the question, what does it mean to
> > grasp facts? How does one go about it? To answer those questions
> > context must play a role because it's a fact fundamental to human
> > consciousness: we only know so much.
> Well of course.
> But it occurs to me, were Objectivists back in 1980 or so certain
> that smoking tobacco did not contribute to cancer?
AFAIK, Objectivists, some of them anyway, made two points about
smoking -- it does not cause cancer and, along the same lines,
statistics by themselves aren't a valid means of establishing
causation. And even there, I might be wrong about what was said.
After all, I wasn't alive in 1980!
> > Okay, but then you're left with the conclusion that nothing is true,
> > and if it is you can't know it, so what the hell, let's all flap our
> > arms and fly because maybe we can.
> Not that nothing is true, but that human beings cannot have certain
> true knowledge.
> It seems to me that Objectivists agree with this and then just redefine
> "true" so that then can have certain true(Objectivist) knowledge.
Here's what Objectivists do -- they acknowledge the limitations of
human knowledge and then ask, by what means does a non-omniscient,
fallible being obtain valid knowledge?
You have to define epistemological concepts according to the nature of
human consciousness because they DEPEND upon human consciousness.
There is no "truth" apart from a human being who can grasp the truth
and there is no "certainty" apart from a human being who can attain
certainty. There is no evidence, no doubt, nothing without a human
being whose consciousness has identity.
Why would you arbitrarily define certainty in such a way as to make it
impossible? For what reason? Objectivists have a very specific
reason for defining certainty the way they do -- because it is
possible and because it is necessary. It is necessary for a being who
lives by the use of his mind to know when he need not doubt his
conclusions, i.e., when doubt serves no purpose but to harm his
ability to think and act.
As I've written elsewhere, all epistemological concepts have to be
able to be reduced to EVIDENCE. If an epistemological concept has no
relationship to evidence (the link between reality and knowledge) it
is useless, invalid, and harmful.
That's why we are right to reject a definition of "truth" which
sunders truth from evidence; that's why we are right to reject a
definition of "possible" that sunders possibility from evidence;
that's why were are right to reject a definition of "doubt" that
sunders doubt from evidence.
All Objectivist epistemological concepts are reality oriented in that
they take into context the nature of reality AND the nature of human
consciousness.
> > As I've pointed out to Gordon,
> > once you accept the premise that we can't know what's true then you
> > have to accept the flip-side -- we can never know what's false.
> You work with the odds.
Why? And to what end? And how do you determine these odds? By what
standard?
> > This
> > fact destroys the so-called scientific alternative of Popperism
> > because it shows it for what it is -- epistemological bankruptcy.
> There you go, using loaded terms like "bankruptcy".
> I could say that Objectivism is a philosophy based on a number
> of equivocations from my point of view. Let's keep it above the
> belt.
> Truth be told I am not so much against certainty as I am
> against authority. I always question authority. I am really
> certain only of what I know personally or can personally trace
> to reliable sources I consider reliable.
Good, because our only connection to reality is our own mind, which
I'm sure I don't need to tell you.
> > Well, then you're only proving my point -- precision matters
> > when it matters and when it matters this marks a limit of a theory
> > that does not give you that kind of precision.
> I still don't get your point.
> By my standard of personal knowledge I know, I am certain, that
> Newton's theory will always give a different answer from GR, and
> that an measurment of sufficient precision will show that
> GR is closer to what is really there in the universe.
The implication is that a ruler doesn't tell us "what's really there".
But that's not the case at all, when you keep in mind the purpose of
measurement which is not to give some suppossed "metaphysical
measurement". If you want that then you simply choose the thing
you're trying to measure as your standard, call it "gloop" and bingo,
you have exactly one gloop.
But, as I've explained elsewhere, that isn't necessary.
> > There is another point of clarification, here: there might also be
> > cases where Newton's theory isn't accurate.
> I'll say it one more time. It is never accurate. It can be good
> enough.
I don't recognize the distinction. It sunders measurement from the
purpose of measurement and implies that the standard of measurement is
some "metaphysical ruler" that does not exist.
[...]
> > Back to my previous point -- to the extent that the limits in
> > precision result in inaccuracy, Newton's theory doesn't apply.
> I just do not understand why one would want to think this way.
> To me it seems so muddleheaded.
> Its true here but its not true there, depends on how accurate
> the measurements are... My way of thinking is so much clearer.
> It is false, but approximately correct in some domains.
How's that not clear? It's just like saying you don't measure atoms
with a tape measure. The minute I see an Objectivist using a
microscope to build a house or Newton for GPS I'll accept that the
Objectivist theory is muddleheaded.
> > I'm not sure I know what you're saying -- that it doesn't refute
> > skepticism, or that it is wrong for claiming skepticism makes
> > omniscience the standard of knowledge...or maybe something else.
> It is wrong for claiming that skepticism makes omniscience the
> standard of knowledge. That is a good way of putting what I am
> saying.
But it does, because otherwise you can't get to 100%...ever. IOW,
100%, in your view, means and requires omniscience. You say, "but we
can have 99%!" and I say, okay, but that still leaves omniscience as
the standard, doesn't it?
[...]
> > which is itself false. Besides, by the standard you invoke,
> > relativity is only approximate,
> I expect that it is. After all human knowledge is limited.
> You agree right? To claim otherwise would be to claim that in
> relativity humans had attained omniscience which is impossible.
> Don't you agree?
I agree completely which is why I don't make omniscience the standard.
> > but maybe more approximate which
> > leaves us no better off because it still requires a qualifier.
> We don't know the quantifier. Someday it will be found. Or not.
And on the day that qualifier is found will you reject GRE as false?
> But the search goes on. Science is always looking to increase
> precision and range of applicability of theory and experiment.
Exactly -- our knowledge increases, expands, grows. That's the point
I'm making and it's that fact I capture by pointing out that knowledge
is contextual.
Robert Kolker
Tom Clarke wrote:
> So far Einstein's theory has survived every test thrown at it. It has now
> been checked to a precsion of many decimal places [lurkers help
> me out, I can't find the exact number easilty 10?]
>
Einstein's theory has not be thoroughly check in the case of very strong
gravitational fields. The strongest gravitational fields we know of are
found in and around black holes and neutron stars. We do not have any
nearby examples of either to which to send probe vehicles. Eventually we
may find a way to test GTR in strong field as thoroughly as it has been
tested in a weak field.
Another factor is the impossibility of shielding gravitational effects.
For this reason we know the gravitational (Cavendish/Newton) constant to
about 5 or 6 places. In quantum electrodynamics where the fields are not
themselves charged (unlike a gravitational field which itself
gravitates), the precision is in the range of 12 to 15 decimal places.
Finally there is the mathematical complexity issue. The Einstein field
equations have their best knows solutions in the spherically symmetric
case (Schwartzschild, Kerr). The full bore field equations are
non-linear and are mathematically less tractable.
Bob Kolker
Robert Kolker
Don Watkins III wrote:
> This is why, even for a theory as well-tested as Newton's, it was valid t
> o keep
> trying to "break" it -- to determine its limits, which we did with great
> success, leading to a more expansive and more precise theory.
The general kinds of limits to Newton's theory have been known for over
a hundred years.
It is Galilean invariant, therefore incorrect. Consequently Newtonian
mechanics is not comptable with electrodynamics. Einstein fixed that. To
find where Newton's mechanics goes awry look at the quantity;
gamma = Sqrt(1-v^2/c^2) where v is the velocity measure in some
inertial frame. The further from 1 that value is, the more wrong
Newtonian predictions become.
Newtonian momentum mass*velocity is not conserved in collision, but a
different (and more correct) definition of momentum is:
mass*velocity/gamma. None of these defects reflects unfavorable on
Newton and his classical succesors. They simply did not have the
technology to see the defects until late in the 19-th century.
Bob Kolker
Robert Kolker
Fred Weiss wrote:
> Why not astrology? Apparently to some of our opponents Newton isn't much
> better than astrology.
Nonsense.
> Astrology is also sometimes correct by coincedence
> which I gather must also be the case with Newton since it seems also to be
> sometimes correct even though it's false and the "cause" it falsely
> attributes to the phenomena it incorrectly measures really doesn't exist.
If you are referring to gravity, Newton very cleary says he had no
hypothesis to account for gravity. He wrote it clearly in Lain. He
derived his inverse square law from the emprically correct Keplarian
third law.
The case where Newton was most incorrect was his hypothesis about the
nature of light. He thought light was the flux of teeny tiny massive
particles. Later on he was partly vindicated. Light is particulate
(photons), but the photons have zero rest mass. His hypothesis did not
account for refraction correctly and would not have predicted wave-like
interference. Thomas Young demonstrated wave-like interference in the
early nineteenth century. That pretty much shot Newtons particulate
theory in the head. Particulate light was revived by Einstein in one of
has 1905 papers on the photoelectic effect (Einstein had a grand slam
year in 1905).
Bob Kolker
puppe...@hotmail.com
> None of these discussions imply *nor need they* that the "Second Law" won't
> apply at *very* high velocities and none of them therefore pronounce that
> the law is wrong. Because it isn't.
Try building a CRT there Fred. The relativistic corrections
on electrons are large enough to be obvious in higer voltage
CRTs. To say nothing of trying to understand magnetism
without relativity.
When you get a street map of a city, does it show the curvature
of the Earth? Does the "context" mean that it is correct that
the Earth has no curvature? What about when you get a geo-political
map of just the lower mainland US? See any curvature? Has it
gone somehwere while we were stealing context? Would a theory
that the Earth has no curvature be right in "context?" Or would
it simply be a handy approximation that has only very tiny
errors in certain situations? And would you have trouble knowing
the level of accuracy involved?
Do you ask how I can get to work in the morning without fail if
the "flat city" theory is wrong? Do you gobble at me for claiming
the "flat country" theory is wrong because I can fly from New
York to LA? Is the basic explanation suddenly correct "in context"
if my journey is short enough or I am sufficiently non-accurate
with my distance measures? Is there, in fact, no objective
reality of a round Earth? Or are the flat-Earthers really correct
"in context?"
The theory that the Earth is flat is wrong. Yet they still teach
people to draw maps of cities without showing curvature. How come?
Socks
Robert Kolker
Gordon Sollars wrote:
> An instantaneous force that obeys an inverse-square law. I had just
> told you above. Do you really read my posts before you reply or not?
Yet Newton, himself, could not figure out how a body HERE can exert a
force on a body OVER THERE without some intermediate method of
trasmission of the force. Newton said he would feign no hypothesis on
this matter and posited the inverse square law of gravitation because it
followed from Kepler's third law of planetary motion in a special case
and implied Kepler's third law in the general case. An interesting
combination of induction and abduction [1].
Bob Kolker
[1] For more on Abduction (nothing to do with kidnapping!) look up
Abduction and C.S.Peierce on the Web. Abduction in simplest terms if
finding the most likely hypothesis to imply ("explain") an observation.
It is not necessarily found by culling through a large pile of facts
(that is Induction). Kepler found his laws of planetary motion by
Induction, by curve fitting to Tycho Brahe's numbers.
Robert Kolker
Don Watkins III wrote:
> Unless you have a specific reason to doubt, including lack of evidence, m
> issing
> evidence, or something along those lines, doubt is epistemologically invalid.
>
Another case for having grave doubts about a theory is that it is too
adjustable. If it can be re-parameterized after every adverse
observation, all it is, is a bookkeeping machine for tracking
observations, and not a good predictor.
When a theory clearly shows symptoms of advances ad-hoc-itis it is time
to buy a new one.
Bob Kolker
Tom Clarke
> "Arnold" <arnold_br...@hotmail.com> wrote in message
>
> >.... Tomorrow we study astrology."?
>
> Very funny.
>
> Why not astrology? Apparently to some of our opponents Newton isn't much
> better than astrology.
This is only apparent to someone who has not correctly integrated
science into their philosophy.
> Astrology is also sometimes correct by coincedence
> which I gather must also be the case with Newton
That Newton is correct by correspondence is only gathered
by someone who has not correctly integrated the basic ideas of
mathematical physics.
> since it seems also to be sometimes correct even though it's false
The idea that something can be correct even though it is false
only troubles someone who has not correctly integrated the
idea of approximate.
> and the "cause" it falsely
> attributes to the phenomena it incorrectly measures really doesn't exist.
Also only a problem for someone who has not correctly integrated
the concept of scientific theory.
Tom Clarke
Tom Clarke
> "Tom Clarke" <tcl...@ist.ucf.edu> wrote in message
> news:ab311d64.03042...@posting.google.com...
>
> > The only certainty is in uncertainty, to try for a pithy statement.
>
> No exceptions, huh?
You don't expect a short pithy statement to be true without
qualification do you?
But since true objective certainty(English) implies omniscience about
what will happen, I would say that this is something that does not
exist.
Oh, with careful attention to detail on can get close to
true objective certainty(English) but even NASA can't
always get it right.
> Have you...err....examined everything in the universe and every bit of
> knowledge and found this out?
Of course not. But I do know that men are non-omniscient
and fallible. Or do you think they are omniscient and infallible?
> Also I'm curious what method did you use to come to this conclusion and why
> do you think that's the correct method?
Experience. In everyday life things often don't turn out as expected.
Historically, old theories are found wanting and are replaced by
new. The alternative is human omniscience and infallibility.
But of course I am not omniscient and infallible so I could be wrong.
Are you omniscient and infallible?
Tom Clarke
Gordon Sollars
> Yet Newton, himself, could not figure out how a body HERE can exert a
> force on a body OVER THERE without some intermediate method of
> trasmission of the force. Newton said he would feign no hypothesis on
> this matter and posited the inverse square law of gravitation because it
> followed from Kepler's third law of planetary motion in a special case
> and implied Kepler's third law in the general case. An interesting
> combination of induction and abduction [1].
See my reply to Betsy. It would be pedantic to say that "atoms" do not
exist /because/ it turns out they have smaller parts. A causal
explanation in terms of atoms need not be wrong because atoms have
parts. But a causal explanation using an instantaneous force /is/
wrong.
....
> [1] For more on Abduction (nothing to do with kidnapping!) look up
> Abduction and C.S.Peierce on the Web.
Peirce rules! The first pragmatist, btw.
> Abduction in simplest terms if
> finding the most likely hypothesis to imply ("explain") an observation.
> It is not necessarily found by culling through a large pile of facts
> (that is Induction). Kepler found his laws of planetary motion by
> Induction, by curve fitting to Tycho Brahe's numbers.
And I would say that Kepler abducted that /this/ kind of curve would
fit, and then checked it to see. But you know this history better than
I do. There all all manner of curves that could fit, and if he had
started at the wrong end, he would have been dead before he got to the
ellipse. Why did he start with conic sections? I would conjecture it
had nothing to do with induction, but because people started from the
notion that the orbits were circles. But that was based on the idea
that circular motion was "perfect" not on induction.
--
Gordon Sollars
gsol...@pobox.com