>>But our accumulated scientific knowledge is a collection of theories!
> It is simply not true that our scientific knowledge is produced by
> theories. Most of our knowledge is non-theoretical and even most of our
> scientific knowledge is non-theoretical.
Philosophers of science from Hesse to Hanson to Kuhn have made compelling arguments debunking the notion that there is any "non-theoretical" scientific knowledge. Theories are the foundation of scientific practice; without theories, we cannot even measure anything!
>
> But most scientific knowledge is simply descriptive and observational.
--And this is the crux: we need theories to effectively observe the world and describe what we observe. Logical positivists tried to create nontheoretical "protocol sentences" that describe observations devoid of theoretical content, and they failed miserably.
>>I think this hinges on different definitions of "theory". Put most
>>simply, a theory explains the observed relationships among two or more
>>variables. I suspect Jerry is working with a different definition.
>
> Your suspicion is correct. Your definition is so minimal as to make
> absolutely any observation a theory. This definition is fine with me but if
> so we will have to find another definition for the kind of "theory" that
> Chomsky discusses when he says that "universal grammar" is more a "research
> program" than a theory; or the kind of theory that S. J. Gould discussed in
> his long chapter One of "The Structure of Evolutionary Theory." Or the kind
> of discussion about theory that revolved around the scientific debates over
> the meaning and theoretical basis of the periodic table that took place in
> the first forty years of the 20th century.
Following Carrol, try this on for size: just like any other word, the word "theory" can have different meanings in different contexts. Above, I provided a simple definition of theory in the sciences, but that is not the only way the word theory is used in our society. If I use the word "culture" one way in microbiology and other way in anthropology, it's silly for me to get indignant because anthropologists use the word differently than microbiologists do. --And just so with the word theory.
Miles