From: George Murphy (gmurphy@raex.com)
Date: Sun Jul 13 2003 - 19:16:41 EDT
Glenn Morton wrote:
>
> >-----Original Message-----
> >From: D. F. Siemens, Jr. [mailto:dfsiemensjr@juno.com]
> >Sent: Saturday, July 12, 2003 10:20 PM
> >To: glennmorton@entouch.net
> >Cc: hvantill@chartermi.net; asa@calvin.edu
> >Subject: Re: Predetermination: God's controlling will?
> >
> >
> >Glenn,
> >I'm not talking about nonsense. The YEC position is not scientific.
> >Einstein's two relativity theories are. I noted Whitehead's attempt to
> >replace Riemannian geometry (1925--if my memory serves). It fit what was
> >known, but not what was later discovered. A later attempt to "correct"
> >Einstein was produced by Dicke and someone whose name I don't recall.
>
> Brans-Dicke theory I beleive it was. See Thornton, Misener and Wheeler,
> Gravitation, p1048 and following and 1068 and following.
>
> Now, while I believe there are an infinite number of theories, the fact that
> they are so hard to find tells me that they are not all equally good.
>
> If there are an infinite number of theories to explain the facts of
> relativity all of which are equally good, why are they so difficult to find?
> I know of none as of this time, since Whitehead, Brans-Dicke and the rest
> have been refuted. The only reason I can see for believing an infintitude of
> theories is if they are trivial, non-testable clones. That is why I cited
> the YEC stuff.
>
> >Many predictions identical to Einstein's, one clearly different. That one
> >did it in after the experimentalists were able to mount a test. There was
> >an article on these multiple theories in /Scientific American/ a goodly
> >number of years back (can't locate the reference), listing a couple dozen
> >alternatives. Not all, if I remember correctly, were intended to
> >supplant: some were designed to clarify. Given the complexity of
> >relativity, I don't expect to see a large number of alternates. That
> >there are any indicates that scientific theories are not unique to a set
> >of data.
>
> I would agree with that.
There is a large - potentially infinite - number of possible theories of
gravitation which are viable to a certain degree because there is a large number of
mathematical structures that to various degrees of approximation give the same results
for different tests. I.e., when certain quantities are sufficiently small, the theories
of Newton, Einstein, Whitehead & Brans-Dicke, as well as others, predict elliptical
planetary orbits. When you start going to better approximations, some theories start
falling by the wayside. You can start generating such theories even within the
Newtonian paradigm by making the force dependence an inverse 2 + small number power or
by fiddling with Poisson's equation.
The Brans-Dicke theory hasn't been shown to be precisely "wrong". Rather, it's
been shown that a new parameter that occurs in the theory (omega, as in MTW p.1070) has
to be larger than a certain value to fit observations - large enough that I think most
theorists now consider it rather artificial. In the same way, the Michelson-Morely
experiment in itself doesn't allow you to say that there is absolutely no "aether wind"
but only that its speed relative to the earth is less than a certain value.
The Brans-Dicke theory wasn't proposed as a "correction" to general relativity
in the sense of trying to fix some observation. It was originally proposed as an
extension of Einstein's equations which could, it was hoped, incorporate Mach's
Principle, but it did predict a different value for perihelion precession. Dicke then
measured solar oblateness & got a value that would have destroyed the good agreement
between observation & general relativity, with the B-D theory able (by suitable choice
of omega) to make up the discrepancy. But his measurement of solar oblateness didn't
hold up.
We can talk about one theory being an approximation to another because we're
dealing with the mathematical structure of theories. If you tried to talk about the
relationship between YEC and RG (real geology) in a similar way, you might say that YEC
approximates RG for distances into the past of a few thousand years, but for more than
that YEC blows up. But this is just a sophisticated way of saying "nonsense."
Shalom,
George
George L. Murphy
gmurphy@raex.com
http://web.raex.com/~gmurphy/
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