From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: VERY fundamental question
Organization: University of Virginia
Date: Thu, 15 Oct 1992 05:33:34 GMT

In article <1992Oct15.020134.8353@nuscc.nus.sg> matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:
>ct@dde.dk (Claus Tondering) writes:
>: A: Would you explain something, please?
>: 
>: B: Certainly, what is it?
>: 
>: A: How does a magnet work? I mean, when I place a magnet close to, say,
>:    a needle, the needles moves. What makes it move? How can the magnet
>:    exert a force on the needle over a distance? It seems like magic to
>:    me.
>
> B: We don't know. Yet. That's all. Now if you ask most people, they
>will go into a long metaphysical diatribe and attempt to dismiss your
>question as "mere" metaphysics: to which you ought to respond:
>physician, heal thyself.  However, you do of course need to understand
>what is meant by "explanation". As everyone knows, any series of "why"
>questions can be extrapolated arbitrarily far. Contrary to popular
>belief, however, this does not mean that "why" questions are outside the
>province of physics. For in any such series there will come a point at
>which the appropriate response is "why not?".

     The difficulty with admitting 'why' questions of a certain nature
     is that you get answers like Albian's.  At some point it stops
     being 'how' and becomes 'why'.  You apparently consider the sequence
     of questions leading to that difficulty a series of 'why' questions,
     rather than a series of 'what' and 'how' questions.  It seems to make
     more sense, though, to admit the different nature of the question
     by describing them as different types of questions.

     And I believe that Mach and other positivists would have held
     to the 'popular' view (actually not so popular when you hear
     some of us speaking or writing).

>To Kepler it seemed perfectly reasonable to ask: why are there six
>planets? Today, with our greater knowledge of the origin of the solar
>system, we would not think this a sensible question. If I were asked why
>there are 9 planets, I should respond: why should it not be nine? It
>could have been 8, etc.
>You could equally well have asked me: why does the Earth go around the
>Sun. I would have replied: because there are no forces acting on it, it
>follows a geodesic in the underlying geometry. Now, before you spring
>another "why" on me , notice that I have answered your first "why". The
>fact that I was able to do so at least proves that your "why" question
>was not meaningless or unphysical. Now, you are going to ask me: why do
>free particles follow geodesics? And I shall reply: what would you have
>them do? Geodesics are the geometrically meaningful curves in a
>semi-Riemannian manifold; thus I feel no surprise at the fact that free
>particles correspond to geodesics. It is deviation from geodesics that
>requires explanation.

     You'll notice that you have no trouble in any of the above situations
     with losing scientific meaning if you simply ask 'How' instead of 'Why'.
     'How did there come to be 9 planets (if there are 9)?' is a perfectly
     reasonable question.

     Also, you beg the question by answering 'Why does the earth go around
     the Sun?' with 'The earth travels along a geodesic.'
     This is the answer to 'How do we think the earth travels around the
     Sun?'   

     The answer to 'Why' is 'Because the Pixies want it to.'

>Finally, to return to your original question. Magnetism is a
>manifestation of the geometry of five-dimensional space-time geometry.
>The motion of a charged particle in an electromagnetic field is
>geodesic, though it seems otherwise to us because we do not perceive the
>5th dimension. Now proceed as above. I must confess to you, A, that I
>myself am not really sure that I believe this explanation. I put it to
>you just to show that a physical answer to your question is by no means
>inconceivable. All such questions seem unanswerable...until they are
>answered. So the correct answwer to your question is as above: We do not
>know, yet.

     When was the last time you saw the 5th dimension?  Your whole
     answer is simply an approximate construct invented by us to explain *what*
     happens, not why it happens.  The phenomenon does not know whether
     we have developed this current explanation or that current
     explanation.  It simply continues to do what it has always been
     doing.

     So the answer is, as with all physics is 'Because it does'.

                            dale bass



-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
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