Perhaps you have some doubt as to exactly what is meant by
music-thinking. Being somewhat acquainted with composers and with
music, the thought may here come to you that all the music we hear in
the world must have been made by somebody--by many somebodies, in
fact. They have had to sit down, and forgetting all things else,
listen intently to the music-thought which fills the mind. If you will
sit quietly by yourself you will discover that you can easily think
words and sentences and really hear them in the mind without
pronouncing anything. In quite the same way the composer sits and
hears music, tone by tone, and as clearly as if it were played by a
piano or an orchestra. And to him the tones have a clear meaning, just
as words have a clear meaning to us. Naturally, one can see that there
could be no other way. Unless the composer can think out everything
exactly there could be no music, for music must be written, and one
can only write what one thinks. So at this point the thought to
remember is this: Music must exist in some one's mind before others
can have it to hear and enjoy.

In like manner--just the same manner, in fact--the painter is one who
thinks pictures; the sculptor, one who thinks statues; the architect,
one who thinks buildings. They think these things just as you think
words; and as you tell your thoughts in spoken words, so they tell
their thoughts in printed music, in painted pictures, in chiseled
statues, and in erected buildings. Now, from all this it should be
clear to you that there can be nothing which has not first been
thought of by some one. You _think_ the door must be closed and you
close it; you _think_ you must know the time and you look at the
clock; you _think_ the one hand should play more loudly than the other
and you try to do it.