[asa] Theory of gravity

Having now finally watched the rest of the PBS special on the Dover trial, I
have a few questions. I'll just start with one for now.
 
I recall it being mentioned that the "theory of gravity" is the same as the
"theory of evolution" -- both are tentative and could potentially be
disproved, although both have substantially large bodies of evidence in
support of them. I thought that was a good argument at the time, but later
I imagined that someone will criticize that argument on the grounds that
Newton's "laws" are no longer considered scientific theory but laws. As an
example of the confusion of terms, Wikipedia's article "Newton's law of
universal gravitation"
(http://en.wikipedia.org/wiki/Newton%E2%80%99s_law_of_gravitation) starts
with the statement: "Isaac Newton's THEORY of universal gravitation is a
physical LAW describing the gravitational attraction between bodies with
mass."
 
As someone with a fair amount of education in science, I realized I didn't
have a completely solid grasp of the difference between a law and a theory.
My first thought was a law is more sufficiently proven or demonstrated than
a theory. However, on reflection, I think a better explanation is that a
scientific law attempts to describe an observation in nature with
empirically derived analytical formulas, while a scientific theory attempts
to explain the observations (causes, etc.). So is gravity a law or a
theory? If I'm not mistaken, it's both. The law of gravity (Newton's
generalization, now superceded by Einstein's equations) is given by
F=G(m1*m2)/r^2. This is empirically derived and demonstrable (again, with
qualification by Einstein in special cases). However, the theory of gravity
seeks explanation by proposing the source of the force of gravity, such as
gravitons, etc., which is still in the theoretical stages, with various
alternative proposals. Is this a fair assessment? Is it true that
gravitation, or at least some aspect of it, is still "only a theory" (to use
derogatory YEC-speak)?
 
The "theory of evolution" attempts to explain the mechanisms of observed
phenemona. It's clear that this is still a theory in flux, with new
discoveries such as lateral gene transfer, DNA replication errors, etc.,
contributing to biological development in ways not completely understood.
But if a "scientific law" describes observations in nature, at what point
could the observations of evolutionary inheritance be called a "law"? Could
there come a point where certain observations or mechanisms of biological
evolution could become quantified to an extent like Newton's formula for the
law of gravity? Is it there yet? I don't know of anyone using the
terminology "law of evolution" on either side of the debate, although there
was something (either in the program or in a forum discussion on our local
PBS station after the program), where the assertion was made by ID advocates
that "evolution is not the 'law of evolution', but only the 'theory of
evolution' ".
 
 
Jon Tandy
 

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Received on Wed Nov 21 07:24:15 2007