From: platt@watson.ibm.com (Daniel E. Platt)
Subject: Re: STRUCTURE OF TIME
Date: Fri, 09 Oct 1992 13:49:54 GMT
Disclaimer: This posting represents the poster's views, not necessarily those of IBM
Organization: IBM T.J. Watson Research Center

In article <1992Oct8.212221.5633@murdoch.acc.Virginia.EDU>, crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:
|> In article <1992Oct08.200637.162851@watson.ibm.com> platt@watson.ibm.com (Daniel E. Platt) writes:
|> 
|> >|> >A gedanken experiment is an act of faith.
|> >|> 
|> >|>      A gedanken experiment is a construct that admits falsifiability if
|> >|>      it is physics.  It is not an act of Faith.
|> >
|> >Now this I feel misses the point.  I think gedanken experiments are
|> >ways of exploring the consequences of principles or theories in a
|> >more practical setting.  Einstein's relativistic railroads were never
|> >things that one could do falsifiable tests on.  However, they did
|> >provide a good way to articulate consequences.
|> 
|>      I feel compelled to point out that falsifiability does not
|>      necessarily imply that you need to perform the experiment, or even
|>      that you know how.  A mental construct can admit falsifiability, even if
|>      you do not actually know how to falsify it.  If it does not
|>      admit falsifiability, it is not physics.  
|> 
|>      On a more concrete level, these consequences of which you speak
|>      can falsify your gedankenexperiments.  The ability is sufficient.

No.  A Gedankenexperiment can never falsify anything.  It can be used to
analyze consequences.  If those consequences violate other experimental
results, then it is the comparison with THOSE real experimental results that
falsifies the theory.

|> 
|> >These constructs also allowed the exploration of the consequences of
|> >quantum mechanics in areas that lay at the foundation of the field,
|> >such as EPR, Bell's theorems, etc.  So, in this sense, they provide
|> >a way of exploring the scope of theories more than being a way of
|> >enforcing falsifiability.
|> 
|>       Every time you 'explore the scope' you submit your construct
|>       to falsifiability.  That is the whole point of the construct.

No.  None of the results of gedanken experiments falsify anything unless
they are compared to real experiments.

|> 
|> >|>      There is a great deal of difference between Faith and blindly
|> >|>      treading down the path.  Faith is actually the antithesis of
|> >|>      blind treading.  However the discussion of such issues
|> >|>      is certainly best left elsewhere.
|> >
|> >It sounds like you are on the edge of saying faith is not blind, but has
|> >an origin and direction...  Some people have based theology on an idea like
|> >'the universe was created good' ("In the beginning...").  While the textual
|> >sources are flasified (the Babylonian cosmology in the P source, and the more
|> >primitive J source doesn't hold water, even if creationsists want equal time
|> >in our schools), the intent that the universe is good is not
|> >falsifiable; yet it is something derived from experience.  People spend
|> >lots of time talking about it in communicating their experience. 
|> 
|>      I don't want to go too deeply into religion, but I do hope that you'll 
|>      understand.  
|> 
|>      No text or concept taken on Faith has ever been falsified, by physics or 
|>      by anything else.  Try to rid yourself of the rules by which you
|>      are thinking of this.  If one of my tenets of Faith was that the moon 
|>      was made of green cheese, no amount of 'evidence' to the contrary
|>      would suffice to falsify this tenet, simply because evidence does
|>      not matter with Faith.  Evidence has absolutely nothing to do with 
|>      Faith. 

A more liberally theological position would disagree with your definition
of faith.  However, the same problem (situation?) exists in physics today,
when people insist that my coffee cup has a state vector.  Insisting that
the state vector is some substantial thing is a leap of faith, and is
not falsifiable (both those who consider state vectors to be descriptions
and those that believe the coffee cup HAS a state vector would agree on
their observations, and would construct substantively similar descriptions
of the physics).

On the other hand, when I was growing up, a friend of mine said they couldn't
have flown to the moon since 'heaven was in the way.'  Now THAT's a statement
of faith along the lines you're speaking of.  My response was, 'well, where
did they go then?'

|> 
|>      And the creationists should not be allowed ANY time in science classes
|>      because what they preach is not science, it is Faith.  They are
|>      welcome to take their place in the comparative religion class with
|>      the scores of other religions.
|> 
|> >Here's a point I tend to agree with.  One point I feel worth making is
|> >that science is description.  There's lots of people who feel very 
|> >confident in talking about the characteristics of my coffee cup's
|> >quantum state vector, without reference to the idea that this kind of
|> >language presupposes that quantum state vectors are real tangible things
|> >with substance.  I'd tend to say that they are descriptions, just as
|> >'mass', 'momentum', 'temperature', and even 'time' are descriptions
|> >constructed to understand, organize, and predict the behavior of the
|> >universe around us.  Attaching substance to these descriptions is a
|> >*non-falsifiable* interpretation of the descriptions, and seems to 
|> >fall into the area of 'faith.'
|> 
|>      All of these descriptions are certainly falsifiable in that they
|>      are all tentative.  They do not generally fall into the category
|>      of Faith.

As descriptions, they are falsifiable.  Investing them with concrete reality,
beyond simple description, is not falsifiable; it also does not contribute
or detract from the descriptive power of the concepts.

Dan
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