I found the following quote at:

   http://www.musicforthesoul.org/quotes.html

   "All art constantly aspires toward the condition of music"
   "The School of Giorgione," Walter Pater

And at http://www.umass.edu/umpress/fall_99/kirbysmith.html  a reference
to a book, which I'll probably order myself.  Forgive me for quoting so
much of it:

   The Celestial Twins
   Poetry and Music through the Ages

   H. T. Kirby-Smith

   A sweeping historical survey of the relation of poetry to music
   in Western culture

   "All art constantly aspires toward the condition of music,"
   wrote Walter Pater. The Celestial Twins, while recognizing many
   affinities between music and poetry, argues that poetry in Western
   culture has repeatedly separated itself from musical contexts
   and that the best poetry is a purely verbal art.

   H. T. Kirby-Smith makes his case with wit and erudition,
   proceeding chronologically and citing numerous examples of
   specific poems-from Latin, Old French, Italian, Anglo-Saxon,
   modern French, and English. He points out that ancient Greek
   poetry, including the epics, was part of a musical context.  By
   contrast, almost no surviving Latin poetry was written for musical
   performance, but the meters of Latin poetry were borrowed from
   Greek musical meters. Similarly, in their own ways, Thomas Hardy,
   T. S. Eliot, and Langston Hughes all wrote out of musical contexts:
   Hardy from west-of-England songs and dances; Eliot from Wagnerian
   opera and late Beethoven chamber music; and Hughes from blues,
   jazz, and spirituals.

   Although poets from Horace to Shakespeare to Dickinson have
   instinctively recognized the separation of music and poetry,
   there have also been well-meaning attempts to bring these
   allied arts back into close association with each other.
   But in Kirby-Smith's view, poetry of the highest order has
   always maintained a respectful distance from music, even
   while retaining some memory of musical rhythms and organization.

The question of the connection between music and poetry has been on my
mind.  I am reminded of the text by Herman Broch "The Death Of Virgil"
which he wrote with music constantly as a backround structural inspiration.
Awesome text.  Claude Levi-Strauss in the four parts of his Mythologiques
took up the relation between mythological structures of the mind, concrete
categories of perceptions specific to differenct cultural groups, and
musical theory.  He's a little rough on "ritual" and seems to corral it
in with post-modernist attempts to dissolve and disintegrate everything
into the nonsense out of which it came.  But that is just my "first"
impression.

The quote above makes it difficult to determine whether Walter Pater
originated the sentiment or if he was quoting, say, Plato.

The quote is also in Pater's "The Renaissance":

   "That the mere matter of a poem, for instance, its subject,
   namely, its given incidents or situation--that the mere matter
   of a picture, the actual circumstances of an event, the actual
   topography of a landscape--should be nothing without the form,
   the spirit, of the handling, that this form, this mode of handling,
   should become an end in itself, should penetrate every part of
   the matter: this is what all art constantly strives after, and
   achieves in different degrees.  (Renaissance 95)"

This last material was poached or snatched from the following site
http://www.english.uiuc.edu/maps/poets/s_z/zukofsky/scroggins.htm

Which looks very, very interesting.

Otherwise, I have only heard of Walter Pater through the Rhetorical Works
of Kenneth Burke, who had been the "Musical Chronicler" on "The Dial"
an artistic and literary publication in the 20's and 30's based in
Grenwich Village.

Sorry I haven't been able to be more specific about Pater himself.  I'm
ordering the books.  Perhaps more later,

Sincerely

Leslie Bruder