Music and philosophy is very important. All musical styles have a philosophy, both practical and "spiritual".
Practical philosophy:
Is the musical language, how you use, harmony/progression, form, counterpoint, dissonances/consonance, rhythm, use of strong beats, , etc, all the practical tools of composition.
stylus fantasticus for example, is another philosophy of composition;
Athanasius Kircher described it this way :
The fantastic style is especially suited to instruments. It is the most free and unrestrained method of composing, it is bound to nothing, neither to any words nor to a melodic subject, it was instituted to display genius and to teach the hidden design of harmony and the ingenious composition of harmonic phrases and fugues.
Affects (Baroque)
The tools to "paint pictures" with music, the different affects describes different thing, like chromatic passages, dotted rhythms, time signature, key signature, melodic movement, dialogues between voices.
"Spiritual" philosophy:
Was is the aim of music, and was is the music purpose.
Its music about self-realization, God , describe nature, to bring forward the national feelings (like the use of folk tunes etc, Grieg and Chopin is very good examples for that kind of philosophy)
And there is philosophy in performance:
Should we use much vibrato, less vibrato, long phrasing (like linear thinking), short phrasings, articulation, legato, staccato, rubato.
Every trademark of styles is philosophy, there are some styles that have more and some have less.
All the subculture of "shall do, or shall not do" is philosophy, If you read Persichettis book on modern harmony, you can see how modern music has its own philosophy on dissonance and consonance.
What is accepted in music is an philosophy too, many say if you write in an older style, they refer to its as pastiche, and say that the music does not represent our time, which is nothing more then a philosophy. Some say yes, and some say that methods of composition is not limited by time, nor by what era we are in (as a matter of fact, time is always moving, and when we are in the present, an era has not been made yet), another philosophy have your own mind and can choose what ever language and practical methods you want to use, because we are at the climax of musical evolution.
I think every composer should be aware of the this, if a composer is not aware of hes:
Practical Philosophy
"Spiritual" Philosophy
Performance Philosophy
I think the music and its integrity is at stake, how can one write music with so little thought?
Music is so much more then just notes and sound, but what all philosophies, old and present agree on is that music have to express something.
But the differ in the tools, harmony, melodic construction, counterpoint, views on tonality, views on dissonance, views on what the it shall express/describe.
But the goal of music an a wide sense is the same.
Sadly there seem to be many that dont think of this, i read posts where people state that music and philosophy has nothing to do with each other.
" i do it because i like it, or what im told to do", seems like art has become mindless. "Robo-art :(