Re: Modeling reality

[Ludwik Kowalski <kowalskil@MAIL.MONTCLAIR.EDU>]

On Thursday, Jan 23, 2003, John S. Denker wrote:

> And as we have discussed before, the word
> "theory" is a booby-trap.  It has two meanings.
> A "mere theory" means speculation;  this meaning
> has been around for thousands of years.  At the
> other extreme, scientists use the word "theory"
> to mean a grand collection of rules / laws /
> formulas / whatever, giving a coherent view of
> a subject.
>
> We ought to find or invent a new word for the
> latter meaning, to prevent unnecessary confusion
> among non-scientists.

Yes, in a case like this it is the minority (scientists)
and not majority (general population) that should
invent a distinctive way to avoid confusion. What
about a rule that "a qualifier should be used next to
the word theory?" For example, classical theory,
newtonian theory, theory of collisions, theory of
electromagnetism, etc.
> Ludwik Kowalski wrote:
> > This is true for a THEORY. But what about a model?
> > A model, I think, is acceptable even if it is not able to
> > agree with all known facts.
>
> Whoa, be careful.  Remember:
>    "No theory should fit all the facts,
>    because some of the facts are wrong."
>                 -- attributed to Fritz Zwicky

OK, the word "all" was not the most appropriate. A better
way would be to say "facts validated by many qualified
scientists," or something like this. Controversial facts,
such as "cold fusion" should not be included, unless
they become reproducible.

> There are rules, laws, formulas, equations,
> principles, equalities, identities, et cetera.
> I don't see much point in drawing fine
> distinctions among these concepts.
>
> >  A model is acceptable if its predictions agree with
> > facts not explainable by existing theories and
> > models. It is not as good as a theory but it is better
> > than nothing. I would say that a model is a
> > hypothesis, not a theory. Right or wrong?
>
> It depends.  Some models are well-nigh exact.
> Some models are quite sketchy, qualitative,
> and/or hypothetical.  There's a continuum.
> To my ears, calling something a model doesn't
> imply much about where it sits on this continuum.

There is a continuum about nearly everything. This
does not prevent us from trying to define terms as
accurately as possible. Is it OK to use the word "model"
and the phrase "scientific theory" interchangeably?
I do not think so. But many do.
Ludwik Kowalski