Re: [Phys-l] DATA, FACTS, LAWS, THEORIES

["John Clement" <clement@hal-pc.org>]

> What follows was prompted by Nicholas Wade's New York Times Book
> Review (October 11, 2009). My comment is about scientific DATA, FACTS,
> LAWS, THEORIES, ETC. I hope this will be useful. Distinctions between
> DATA and FACTS, or between LAWS and THEORIES are important. Comments,
> as always, will be appreciated.
>
>
> c) A LAW is a generalization of facts. I am thinking about Kepler's
> Laws (how planets move), about Mendeleyev's Law (how elements are
> ordered in a chart), Faraday's Law   (how changing currents can be
> induced), etc.
>
> d) A THEORY is an explanation of a law. I am thinking about Newton's
> gravitational theory, about Maxwell's equations, about quantum
> mechanics, about Heizenberg's principle, etc. Distinctions between
> laws and theories (and between facts and theories) are worth
> recognizing. Unfortunately, this is not always done.

I would assume the article in question is "Evolution All Around" criticizing
the book " THE GREATEST SHOW ON EARTH The Evidence for Evolution" By Richard
Dawkins.

The review is quite reasonable and actually only differentiates between
theories and facts.  It says that Dawkins strays into saying evolution is a
fact and not a theory or model.  This looks like a very reasonable criticism
of Dawkins.  As far as I can see it makes no general definitions of the
other words.

As to a law being a generalization of facts, that is not exactly how the
term is used.  Virtually all laws are equations or relationships which may
be either general or specific.  If you look at all of the laws they are
generally equations such as Boyle's law, Newton's laws...  Sometimes the
equation is merely implied as a statement of a principle.

A theory is a consistent framework for relating various laws and facts so
that one can make predictions about unknown situations.  Sometimes you can
also call a theory a model.  But in no sense is it an explanation.  The
theory itself can often not be explained, but it can be used to generate
predictions.  If it can be explained that would be in terms of another
theory and eventually you get to postulates or assumptions which have no
explanations, and are sometimes do not even look reasonable, but they work.

As to there being 4 moons of Jupiter, it is easily made into a fact by
saying there are 4 Galilean moons of Jupiter.  This makes the definition
exact in historical terms.  One can easily get balled up in the question are
there 9, 12, or 8 planets around Sol.  It is a matter of definition, and is
not worth arguing.  There are historically 9 planets.  This may be a good
topic to bring up with students and give them the information about masses
of the various large objects including the ones outside of Pluto's orbit.
Then let students decide and debate what they think before presenting the
standards group's thinking.

John M. Clement
Houston, TX