🚀 go-pugleaf

In article <schiller.726316570@hpas5>, schiller@prl.philips.nl (schiller c) writes:

|> However my son ! Facts are never presecribed by theory, facts are the 
|> results of observation.

I don't have much of a clue what "prescribed" means here.  Perhaps
what is meant is that the range of "possible facts" or the range
of "descriptions of facts" is limited by theory.  That wouldn't be
*so* bad a claim.

|> For example, electrons were there much before quantum mechanics
|> (at least 30 years before) when they were observed in Braun tubes

Ummm.  Something was there.  But were they *electrons*?  Phlogiston
was there much before the phlogiston theory.  Then it seems to have
disappeared post Priestley and Lavoisier.  Of course oxygen was there
prior to the oxidation theory as well.  Hasn't disappeared yet.

|> and similar devices. By the way, your TV and your terminal
|> (except if LCD) is a Braun tube, and a
|> ray of electrons produces the image. No quantum mechanics is
|> necessary to observe this fact ... :-)

Which fact?  The images on the screen or the "fact" that it is
a ray of electrons that produces the image?  (Actually, I don't
like talking about observing facts.  Better to observe phenomena
and treat the descriptions of these phenomena as facts.)

|> Your (wrong) statement that "if we didn't invent QM then we wouldn't have   
|> electrons" is a nice example which shows the difference between a
|> fact (based on observation) and a speculation "prescribed" by 
|> what you (but not scientists) call a "theory", namely your 
|> conviction that theories precede facts ... :-)

Well, I'm not sure the claim was that theories *precede* facts
(certainly not in a temporal sense, perhaps not in a logical sense).
The more sophisticated form of this claim is that the relation of
fact to theory is a kind of mutually parasitic one.  Certainly,
for example, whatever *sense* the term "electron" now has, it has
in virtue of QM.  This doesn't mean that if we didn't have QM
we wouldn't have electrons, but it does mean something to the
effect that if we didn't have *some* theory in which "electron"
appears as a term, then it wouldn't make much sense to speak of
electrons.

However electrons are observed, this is not precisely in the same
manner as cows are observed (you don't need much of a "cow detecting
imaging aparatus" under normal circumstances).  A great deal of
*theory* needs to come into play in order to describe how an electron
is observed (if indeed we want to say that this is possible) or
what "observed" *means* when applied to electrons.
-- 
Gary H. Merrill  [Principal Systems Developer, C Compiler Development]
SAS Institute Inc. / SAS Campus Dr. / Cary, NC  27513 / (919) 677-8000
sasghm@theseus.unx.sas.com ... !mcnc!sas!sasghm