From: schiller@prl.philips.nl (schiller c)
Subject: Re: Which theory before observation ?
Organization: Philips Research Laboratories Eindhoven, Netherlands
Date: Tue, 12 Jan 1993 08:36:05 GMT

sasghm@theseus.unx.sas.com (Gary Merrill) writes:

>In article <schiller.726741786@hpas5>, schiller@prl.philips.nl (schiller c) writes:
>|> 
>|> Wow ! When a sientist pretends to "see" an alpha-particle, in a Wilson chamber,
>|> what he says is an abbreviated form of the following:
>|> 
>|> We see a track. There is a ray of something producing a track. Now let's see if
>|> one can describe this thing in more detail. Let's put the chamber in a magnet.
>|> Ah, the track bends. Ah, the particle is positively charged. The mass over
>|> charge ratio has a certain value. Then one measures the mass. One gets a
>|> certain value. Ah, in the beginning of the century, particles with the same
>|> properties had already been seen, and then such a particle, with that charge and
>|> that mass, was named an "alpha particle". 
>|> 
>|> (This actually was the historical path.)
>|> 
>|> No theory is involved. Just the idea that you see again what you had seen
>|> before. Naturally, you need the concept of mass and charge, and of magnetic
>|> field. But you can repeat the same reasoning for these concepts, just as done
>|> for the concept "alpha particle".

>I love it!  Instrumentalism lives!  Not only is no theory "involved"
>according to this account.  No theory is even *necessary*.  I will not
>attempt to repeat here all of the (well known and telling) criticisms
>of such positions which date back to at least the '30s.  We seem, along
>the way, to have lost track of various claims concerning "facts" and their
>relation to theory.  Perhaps this is because the position has now been
>exposed as the most naive of instrumentalist or operationalist views.  If
>every claim of a scientist that employs a theoretical term (such as
>'alpha particle', 'mass', 'charge', etc.) is simply *shorthand* for
>a "real" observation statement, then of course there is nothing but
>facts.  (Of course we are still left with those thorny questions pertaining
>to why some of these facts seem more factual than others, and why some
>of these facts can be used as *evidence* for others.)


Obviously I embrace the idea that no theory is necessary. (This is to
make you angry a little more ... :-) The historical account even prooves
this to be so. 
Alpha particles have been discovered, not invented. The term "discovery"
expresses the fact that the observation was *unexpected*, in other words,
that there was *no* theory beforehand. They were found by serendipity.

Your position amounts to the denial that discoveries are possible. As a
scientist, I disagree completely. The question if such a thing as a "discovery"
is possible or not is a deep one, but science takes the clear stand that it is.
I am always interested to hear from people who deny the existence of the
possibility of discoveries.  But in my experience, and in that of the people I
see, "discovery" has a real meaning, independent of theory.

I also subscribe to the idea that every theoretical term (such as
'alpha particle', 'mass', 'charge', etc.) is simply *shorthand* for
observations. This is the way physics and the other sciences have grown
and have been developed. 

Btw, "mass of an object"  means "difficulty to move it",
"charge of an object" means "strength with which it moves when approached 
by a stick which was previously stroken by a cat fur". 
These *are* shorthand for observations.

So let me sum with a challenge : can you give a concept in physics which 
is NOT a shorthand for observations ?


 
	  		Christoph Schiller