What is music for?  What purposes do its performers achieve, or intend to achieve?  What purposes do its listeners use it for?  Why do composers or song-writers write it?
These seem to me fundamental questions in any discussion about (say) the public funding of music performances and music education, or (say) the apparent lack of knowledge that some people in Britain have about some types of music, or (say) how to increase audiences for particular types of music.   But no-one seems to debate these questions, or even to raise them.  As a result, there seems to be little awareness that aims and purposes may vary, both across cultures, and over time.   (I am reminded of Alfred Gell’s anthropological theory of art which understands art as the creation of objects liable to be perceived by their audience as objects with intentionality, that is, objects carrying some purpose.)

• To entertain, to give pleasure. The pleasure may arise from the sounds themselves (eg, elements such as the sound qualities, the melodies, the harmonies, the overtones, the timbres, the beat, the rhythms, the combinations or interplay of the various elements), or the performance of the music (the skills of the performers may provide pleasure), or the construction of the music (eg, repetition or novelty, contrapuntalism or other structural features, the composition or improvisation techniques evident to a listener), or allusions to other sounds and music.
• To express some emotion or mood in the composer/writer, or in the performer.  Indeed, music may be a form of encrypted communication, with messages able to be understood by the target audience but not by any others who hear it.   According to Larry Todd, Fanny Mendelssohn wrote lieder (art-songs) to communicate to Wilhelm Hensel her feelings about him; he was later to become her husband, but at this time her parents had forbidden them to meet or to write to one another, even on occasion intercepting a letter he had had written against this order.
• To evoke some emotion or mood in the listener.  The sturm-und-drang movement in the mid-18th century, for example, led symphony writers to imitate thunderstorms and other effects, often seeking to frighten or surprise listeners.
• To express solidarity and communality, whether by performers or by listeners.  See, for instance, Mark Evan Bonds’ great book on how Beethoven’s symphonies were perceived by their audience as expressions of and occasions for communality.  John Miller Chernoff’s observation that African people express their opinion of a musical performance by joining in (themselves performing, singing, beating time, or dancing) is an example of this particular aesthetic of music.  Other examples include the playing of the US national anthem at the Changing of the Guard at Buckingham Palace, London, on 13 September 2001, and the programming of music by American composers for the Last Night of the Proms in London that same week, both acts of solidarity with the USA after the 9/11 attacks.  Given the fact that the US had to fight a war against the British crown to achieve Independence, and indeed had fought a subsequent war with Britain, these were very strong statements of solidarity.
• To inspire listeners to action, as, for example, with the music of the 19th century nationalists such as Verdi, Chopin, Dvorak, Smetana, Sibelius, Hill, etc.   Such nationalist aesthetics may be very powerful:  The white minority regime in South Africa, for example, banned the singing of the hymn, Nkosi Sikelel’ iAfrika (“God Bless Africa”), because of its association with the movement for majority rule. (The hymn is now the national anthem of South Africa.)   Similarly, although Japan’s illegal military occupation of Korea ended in 1945 and both countries are now democracies, Japanese pop music is still banned in the ROK (South Korea).
• To induce altered mental states in listeners, for example, as an aid to entering a trance or to prepare them for some other spiritual experience.  In words of Indian musician Gita Sarabhai (1922-2011) that influenced John Cage, for example, music’s function is “to sober and quiet the mind, thus rendering it susceptible to divine influences.”
• To facilitate some other activity, such as dancing, singing or the recital of poetry, or the ready memorizing of secret espionage codes.
• To think.  Contrapuntal music, in the North German tradition that reached its peak in the middle of the 18th century, used fugal writing as a way of articulating the possible mathematical manipulations (eg, overlay, delay, inversion, reversion) of the theme.  These manipulations may be viewed mathematically as group actions on a musical space.  Similarly, the tradition of western art music from the mid 18th century through to the present day has focused on the articulation of the musical consequences of a theme or motif.   Beethoven, who was never very good at melody-making, was perhaps the best composer ever at development, with Mendelssohn a very close second.  Chopin, by contrast, was good with melodies, but not at complex development.   The development of musical material during improvised performances of modern jazz, of Indian ragas, or of Balinese gamelan scales are further examples.  See, for instance, Paul Berliner’s account of his learning to improvise in jazz.   Likewise, much minimalist music forces performer and listener to pay careful mental attention to aspects of music ignored in the dominant uptown tradition, such as rhythm and metre, and how these vary, concatenate and interleave with one another.  Similarly, the focus, particularly by composers in the American experimental tradition this last 100 years (eg, Cowell, Varese, Cage), on the materiality of sounds is another form of thinking; it is the intelligent exploration of the features of sounds and sound-generating mechanisms, and the consequences of these features.
• To facilitate thinking. I have a computer scientist friend whose attempts to prove mathematical theorems is greatly enhanced if he listens to Bach fugues while doing so.  Likewise, many large corporations transmit low-decibel, high-frequency white noise through their office speaker systems to facilitate work in open-plan offices.
• To come to know oneself.   Using music (or any form of human expression) as a form of thinking, one learns about oneself:   how one thinks, about what one is thinking or obsessing, and what one perceives.  Many visual artists draw or paint to know themselves better, with the resulting drawing or painting a mere by-product of the process.  The same is true of musicians and composers and listeners, and it is why people may be drawn to life as a musician (or artist) despite the consequences.   (I am grateful to conversations with Patricia Cain for this insight.)
• To enable one to seek mastery of the skills and arts involved in composing, performing and/or listening, to train oneself in these arts, to undertake a practice (in the Zen sense of that word)
• To pray.   Much western religious music is expressed in a form of supplication or worship to a deity.  Composing, performing or listening to music may also be understood as acts of piety in themselves, akin to the copying out of sacred texts which some religions, for example, Nichiren Shu Buddhism, consider to be pious actions.
• To channel messages from the spirit world, as Zimbabwean mbira players are aiming to do when playing.   Jazz pianist Craig Taborn has said that he believes “creative endeavours are informed by the interaction with metaphysical forces” and that “Music functions as a means to ‘call down’ those spirits [the spirits of the black improvisational music tradition], so in a very real sense I am not doing anything when the music is truly being made.  It isn’t really me doing it.”
• To communicate with non-material (ie, spirit) realms. Much prayer, indeed, perhaps the overwhelming majority, is not intended to be entreaty or worship of a deity, but communion with spiritual entities.  Music can be a form of such communion.
• To provide soteriological guidance to performers or listeners. Composing, playing, or listening may help one achieve or progress towards salvation. Jazz pianist Craig Taborn again: “All the things people say when they talk about music have to do with entertainment, or some kind of aesthetic advancement.  Yet when they talk  about how music moves them, they talk about other  things:  feelings, times of life, etc.  So I  suppose that for me, music is one of the things we use to get ourselves through life.”
• To provide an unobtrusive background to other events, as Muzak seeks to do, and as much film music appears to be seeking to do.
• To pass the time.  It is true that time would have passed anyway, but one’s perception of the duration and speed of its passage may be altered.

These goals may overlap.  For instance, music may entertain by providing an opportunity for musical thinking.  For musics such as modern jazz improv or classical Indian ragas, the composers, performers or listeners may gain considerable pleasure from the thinking they undertake in order to write, to perform, or to listen to the music.  A listener to music may gain intellectual pleasure by discerning and re-creating the thinking that the composer undertook when writing a piece, or that was undertaken by a performer engaged in an improvisation.  Such pleasure at thinking, in my experience, is similar to the pleasures which people gain by doing crosswords or doing Sudoku puzzles; it may also be a form of mathmind.   This is (writing, performing or hearing) music as thinking, in exactly the same way that drawing is a form of thinking.   As with drawing, the cognitive abilities required to think via music, especially on the fly, should not be underestimated.