Ancient philosophers such as Aristotle and Plato recognised the unity between music and philosophy.

The artistic expression of a piece of music could be described as philosophy using sound. Instrumental Classical music can be a very profound experience and the content of the music can be incredibly descriptive. Instruments playing characters, melodic themes reproduced in a variety of ways during the course of the piece, these are left to the audience’s imagination. This can provide the listener with a wide range of conclusions; from purely enjoying the music, to a deeper understanding of themselves.

Hans Christian Anderson was quoted saying “Where words fail, music speaks” – This is a common feeling between musicians. If asked what music is to them they rarely can give a coherent and descriptive answer. The Film ‘Music’ directed by Andrew Zuckerman 2010 (Also a book of the same name) is a documentary interviewing successful musicians about their lives with music. The film starts with short clips of various artists contemplating in silence; it then becomes apparent the question was ‘What is Music’.
Popular Music is full of song lyrics which border on philosophy. For example Michael Jackson’s song ‘Man in the Mirror’ has the lyric; ‘If you want to make the world a better place take a look at yourself and make the change’. This is a very direct philosophical statement with little room for interpretation. Whereas ancient philosophy can be multi-faceted, a lyric is often much more direct with its message.
Commenting on the social status in the 1970’s Pink Floyd’s song ‘Time’ contained the lyric ‘Hanging on in quiet desperation is the English Way’. This was a commentary of the apathy that was contained within England at that time.
Music allows a platform for artists to directly confront issues which are outside of their music. Often, these philosophical thoughts are the influence for the music rather than the other way around. The album by Pink Floyd ‘Darkside of the Moon’ was very much a context applied to create the music with, rather than a fit to the music that had already been created.
The Beatles lyric ‘Love is all you need’ from the song ‘All you need is love’ is possibly the most simplistic message that a lyric can contain, but the impact felt on the audience of that time was a deep resonance. Brian Epstein describes this “It was an inspired song and they really wanted to give the world a message. The nice thing about it is that it cannot be misinterpreted. It is a clear message saying that love is everything.” From this example it can be assumed that music for many artists is a vehicle of expressing thought and thus creating the reason for the creation of music.
Aristotle discusses this in his Politics Book VIII Chapters 5-7. This dialogue attempts to make sense of the value music holds and its place within education. “There seems to be a certain connection between harmony and rhythm; for which reason some wise men held the soul itself to be harmony; others, that it contains it.” Aristotle acknowledges here the mystery of music and its larger relationship with life itself rather than a form of pleasure akin to wine and sleep.
Arthur Schopenhauer was quoted with this statement.  “Music expresses the inner being, the world-as-such in a most general language, namely in mere tones: but it does this with greatest determination and truth. The composer reveals the innermost being of the world and expresses the deepest wisdom.”
“Just for this reason the effect of music is so much more mighty and vivid, than the effect of the other arts: they only talk about the shadow, but music about the essence. Supposed we were successful, in giving a totally right, complete and detailed explanation of music …, then this would be … the true philosophy.”
A reoccurring theme in philosophical thought seems to be that music is the key to understanding our deepest questions about life. The interesting aspect to pre-modern philosophers is that they are commenting on music that generally had no lyrical content, surmising that composition is more than adequate at posing questions and answers that other forms of expression cannot.