Re: How can I tell if F is a string or if it is a number?
- From: Pioneer1 <1pioneer1@xxxxxxxxx>
- Date: Mon, 19 May 2008 05:57:05 -0700 (PDT)
On May 6, 12:08 pm, tc...@xxxxxxxxxxxxx wrote:
The calculation *does* use equations that contain
force, and then eliminates them.
Yes. You are right. I realize that physicists sometimes call the
derivation process "calculations." Maybe I should have asked if the
orbit knows about preparatory calculations and temporary terms we
might write and then eliminate. My personal opinion is that such
transitionary terms are not visible to orbits once they are
eliminated.
. . . physicists seek
to find laws that govern *all* physical phenomena.
I understand that it makes sense to have a unifying principle, if
possible. But are you saying that the force that Newton assumed
described orbits is the unifying principle for aerodynamics, materials
science and the rest of physics? Maybe I'm misunderstanding you but
that force assumed by Newton does not even enter the orbital
formulas.
I am not advocating inventing a new set of assumptions to explain each
situation. I agree with you that the business of science should be to
look for general principles. But I disagree that instead of looking
for such principles we should fit everything into the Newtonian
doctrine and always assume that the doctrine is right. In the case of
orbital equations mathematical description of orbits says that orbits
are independent of force. Newtonian doctrine says that orbits are
caused by force. I choose to respect the authority of mathematics
instead of the authority of Newton. This may not be how physicists
reason. But I was always taught that science means to respect the
authority of mathematics and reject any other kind. If my
understanding of mathematics is wrong, that's another thing and I
would appreciate corrections.
Alternatively, I could seek a few very general principles that apply in *all*
situations.
I agree with this view. But to me there is a general principle that
comes before Newton's doctrine of force, and that is Kepler's rule
because it came from observations. I believe this because Newton
defined force on Kepler's rule in such a way that the force term must
be cancelled in order to make orbital computations. This fact tells me
that unless Newton discovered a new proportionality replacing Kepler's
rule, astronomical computations must be done with Kepler's rule. As
far as I know, Newton did not discover a new rule, so physicists
compute with Kepler's rule and call it Newton's laws.
But as I wrote to Patricia Shanahan, finally I realized that the
difference is with the way physicists use Kepler's rule. They do not
use the proportion, which would be very cumbersome, but they convert
the proportion to an equation by writing it with a unit and because
they wrote with a unit named after Newton and because of historical
reasons they believe that they are applying Newton's laws to solve
physical problems.
Newton's axiom of the doctrine of force as the universal cause is
believed by physicists to be the reason why the computational device
called Newtonian mechanics works. I am saying that this is not true
because algorithms are independent of axioms. In the case of orbits I
see that indeed computations are independent of Newtonian force.
But to
conclude from that one example that forces are *in general* an unnecessary
theoretical device is to take a very narrow view of science. Before you
discard the notion of force, ask yourself if you could calculate the dynamics
of two colliding galaxies without assuming a theory of gravitation. Kepler's
laws won't be good enough any more.
I don't know how galaxy collisions work, so you may be right. But I am
not reasoning from an example. I am looking at Newton's definition of
force. I am looking at the origin of force. I see that Newton's
definition of force adds nothing to Kepler's rule because what Newton
adds, the force term, must always be eliminated to recover Kepler's
rule. And there is no other rule that Newton discovered. What drives
"Newtonian mechanics" is not force, it is Kepler's rule written with a
unit so that it fits into the unit system of physics. This is what
makes Kepler's rule written with GM to appear as if it were an
integral part of physics. Is there another origin for force?
If a simple theory of gravitation
explains both galaxy collision and orbital motion . . .
The theory of gravitation that you mention is the consistent system of
units that was developed over many centuries by Laplace, Euler, Gauss,
Lagrange, Hamilton and many others. This system is made of many
algorithms developed to use the Keplerian proportion with units within
physics. These algorithms are independent of the doctrine of causes
and forces invented by Newton. I believe that the general principle
that unifies physics is not the Newtonian force but the unit system.
Do you have any comments about this?
then it makes sense to
claim that gravity is at work in orbits, even if for some particularly simple
problems you don't need the general theory.
The gravity term that you say explains the orbit is eliminated. How do
you justify the claim that gravity explains orbits? The mathematical
formulas say that orbit is independent of Newtonian gravity.
.
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