Bill Pirkle wrote:

>My whole thrust in examining the underlying feeling that motivated a
>composer to do this or that is to better understand how to write it
>(or have my computer write it).  I am amazed at the difference between
>wandering through a museum looking at paintings and taking the tour and
>having them explained by experts.  They point out things that I never
>noticed and I enjoy the painting more by knowing these things.  I was
>wondering if the same thing could be done with music.

Perhaps it has, although not in just the way you describe.  You might take
a look at Deryck Cooke's The Language of Music.  I haven't looked at it
in years but as I recall he discusses the various emotional "meanings" of
various types of melody.  Anyone more familiar with the work, please help
us out here!  But for a good discussion in purely musical terms of why some
music is so moving, I like Tovey's essays and those of Charles Rosen.  For
the latter I recommend three books:  The Classical Style, Sonata Forms,
and Romantic Music.  Another important work that takes a totally different
approach is Leonard B.  Meyer's Emotion and Meaning in Music.  Meyer comes
somewhat from the behaviorist school and tends to explain music in terms
of its building of expecatations and then either fulfilling them or denying
them.  It is when the latter takes place that we have affect, according to
Meyer.  We don't get the expected event, and then we are forced to keep
listening because we are interested that the composer has "fooled" us, and
want to know why.  That's way oversimplified, but that's the approach.
For classics in the philosophy of music, which may touch on meaning and
signification, there are Langer's Philosophy in a New Key, and a sequel
whose title I forget just now.

>I can't help think that the composer's subconscious was actually
>controlling the effort, unbeknownst to the composer.  Freud and the now
>widely accepted notion of a subconscious ...

Not so widely anymore, I'm led to believe.

>...  occurred at the end of the 19th Century after all those 17th, 18th,
>and 19th century composers may have not themselves understood their true
>motivations.

Let's go slowly here.  Is there a risk in saying that there may be
meanings in Bach that he himself wasn't aware of? How can we eliminate
the possibility that we MAY be reading our own feelings and thoughts into
the music instead? The way people hear and respond to music changes over
time.  I sometimes get the feeling you're arguing from the premise that
the meanings (perhaps I should say feelings) in music are necessarily
universal across time and distance.  I think it likely that Bach and his
contemporaries responded to music in ways very similar to each other, and
this is why there was a commonality of style.  If somehow Wagner's Prelude
to Tristan und Isolde were dropped into their midst (this is a thought
experiment I like to use now and then), they probably wouldn't have known
what to make of it, at least for a long while.  What might they say if they
were told "This is what German music will sound like 120 years from now!"
Almost every piece ever written acknowledges in some way what has come
before it--either affirming or denying its heritage, in some measure.
Music has meaning and we respond to it only in a context of shared
conventions.  Shatter too many of those conventions, remove the
culturally-supplied context of meaning, and we find nothing but stray
sounds, that might as well be atoms "whirling in the void" as Whitehead
wrote.

Chris Bonds