The Meaning of Music 
The Meaning of Music Is it possible that the meaning of music is related to evolution, and that music is a song that we sing to attract others sympathetic to our songs? In this case, do we not include in our songs details including who it's for, why it's there, how complex it is? In other words: if we want to be popular, we include within it...
xxxx in his book, The Muse in the Machine, suggests that thought occurs on a scale with extremes at 'high' level and 'low level thinking. Examples of areas requiring the former he places science, logic and mathematics; examples of areas requiring the latter are, according to the book, creative thoughts and activities. His use of the terms high and low is not intended to indicate a qualitative distinction, merely a different emphasis. One of the principal arguments of the book is that artificial intelligence must come to terms with each 'level' if it is ever to truly succeed. The argument is an interesting one, although I feel that his inclusion of 'creativity' as a block in one level is misleading, and one that Richard Dawkins has rather bitterly considered (or at least considered the normal divisions between 'art' and 'science') in Unweaving the Rainbow. Similarly, as xxxx points out, Penrose (as he quotes) often has mathematical ideas 'while shaving' and so maybe the point should be emphasised that creativity happens in science too.
Bearing all this in mind, I think it is interesting to consider the uses of music in society and from this information try to come up with a workable understanding as to at least one of its meanings. Many commentators have done similar things, but, ironically, usually either ignore the stylistic component or try to accommodate stylistic diversity in a single 'theory'. In my opinion, this is extremely difficult as I think it is probably the case that different sorts of music utilise different parts of this thought-level scale and that people use different parts when they listen to music.
A simple example is to investigate the 'use' of simple background effects. Under some circumstances, silence can be desirable and delightful and any sound can be irritating and unnecessary. Under other circumstances the reverse is true and many people prefer to 'use' background sound - music and/or speech in order to counteract te more negative possible qualities of silence: boredom, lonliness, emptiness, etc.
In a very similar way, music can be welcome, actively enjoyed, very irritating, actively disliked, liked under certain circumstances but not at others. This is, of course, true of many activities and artifacts to some extent, but there is a way in which music seems to have a particularly strong effect. People commonly use music as a personal or group identifier and, as has been stated by other commentators, as a way of bringing about feelings of unity.
Music, like any other form of technology, is the application of energy, and thus order, to (musically) disordered systems.