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

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

Boyles law, Newton's laws, Kepler's laws, Hooke's law, The law of
conservation of energy... have very little in common except for the fact
that they are called laws and that they are relationships between variables.

One might call conservation of energy a universal law meaning that there are
no known exceptions, while Hooke's law is an empirical law which certainly
has exceptions.  Why not have E=mC^2 as a law?  But for some historical
reason it is not.  The term law would seem to imply that it is absolute,
while many laws are only obeyed under certain conditions.

Hooke's law can be easily discovered by a student in a short lab, while
Kepler's laws took years and much struggle to create.  The term law seems to
be applied to various equations almost by accident.  I could just publish an
experiment and generalize it and call it a law according to your definition.
Is Hooke's law general?  Is F=mg also a law?  Or how about Ff=mu Fn?
Sometimes they may be considered laws, but sometimes not.

I object to the word explanation because ultimately one comes up against the
fact that your explanation is just a statement "that is the way it is".
Theories are in a sense complete reasonably consistent models which cover a
whole range of phenomena.  As such they are merely what we use to make
predictions.  They explain thing in terms of other things, but ultimately
they are not complete explanations.  The term explanation leads students and
the public to think that they are final complete explanations rather than
tentative models.

Part of the problem in the past has been the rigid definitions of these
things promoted by textbook authors.  These are not strictly scientific
terms, but partially social and historical.  Making rigid narrow definitions
will be confusing because each scientist has a slightly or greatly different
view of these terms.  So I propose that law is a historical term applied to
a relationship between variables.  It is very difficult to say much beyond
that.  It is easier to say why one is Sir Soandso than to say why something
is called a law.  He was knighted by the queen or king, but laws are decided
by convoluted accidents of history.

John M. Clement
Houston, TX


> > Of course, only things are called laws if they have some general
> > validity
> > and applicability.  But the primary requirement to be a law is that
> > it is a
> > relationship between variables.  Beyond that there seem to be social
> > and
> > political rules that determine which things are called laws.  Newton
> > never
> > called his laws "laws".
>
> A relation between the area of a circle and its radius satisfies such
> criterion. But it not a scientific law. The term "relation between
> variables" is much broader than the term "law. "
>
> In fact, I do not consider mathematics to be a science; it is our
> special language. But that is a different topic.
>
> DATA = what is reported
> FACTS = validated data
> LAWS = generalized facts
> THEORIES = explanations of laws and facts
>
> What is wrong with this? The four words are listed alphabetically.
>
> Yes, I know that other meanings are often assigned to each of these
> four concepts. That is not desirable; it often creates confusion.