From Wikipedia, on the definition of music:
"[there are] those that seek a platonic or quasi-platonic ideal of music which is not rooted in specifically physical or mental terms, but in a higher truth. "
"The platonic ideal of music is currently the least fashionable in the philosophy of criticism and music, because it is crowded on one side by the physical view - what is the metasubstance of music made of, if not sound? - and on the other hand by the constructed view of music - how can one tell the difference between any metanarrative of music and one which is merely intersubjective? However, its appeal, finding unexpected mathematical relationships in music, and finding analogies between music and physics, for example string theory, means that this view continues to find adherents, including such critics and performers as Charles Rosen and Edward Rothstein."