“Rattle big black bones / in the danger zone / there’s a rumblin’ groan / down below / there’s a big dark town / it’s a place I’ve found / there’s a world going on / Underground …” So begins the opening track of Tom Waits’ magnificent Swordfishtrombones. The underground world itself is not described to us, but we are told that it is inhabited: “they’re alive, they’re awake / while the rest of the world is asleep”, roars Waits to a relentlessly marching accompaniment. We are left in no doubt that this hidden world will infringe on our own in way we cannot, dare not imagine. But the rest of the album (and every subsequent album by him) serves as a map to the big dark town he has discovered. He had always sought out dark corners to explore, but with Swordfishtrombones it is as if a whole dark universe is illuminated for the first time.

Music survives because it takes us places, illuminates new worlds of experience. Sometimes it does this hand in hand with language; sometimes it wells up from and fills places where language cannot go.

Of course most music does nothing of the sort: any ill-advised foray into local radio will reveal that music is most often meant to soothe and calm us, to help us forget the big, dark towns of our imagination.

It might be difficult to say without sounding elitist, but much music that is good is not immediately accessible, and possibly never will be to most people. For one thing, you need to know where to look for it, and for another, much fascinating music poses sonic and imaginative challenges. There is something troublesome about people that confront us with our nightmare imaginings, with the beautiful and the sublime, as the title character in Nick Cave’s song The Lyre of Orpheus finds out. Cave’s Orpheus is a gloomy man who creates a lyre out of sheer boredom. The music he plays is so overwhelmingly beautiful that animals detonate in the sky or dash out their brains against the trees in order to avoid it, and his wife Eurydice’s head bursts open at the sound. Orpheus follows her down to hell, still with his lyre in hand. When Eurydice sees him, she says: “If you play that fucking thing down here / I’ll stick it up your orifice!”

But if music can take us down into our own personal underworld, it can also take us to places of such ecstatic beauty that the world seems to be transformed while we listen. Waits himself wrote such a song in Come On Up To the House, the track that closes 1999’s Mule Variations. Dylan’s Mr Tambourine Man never fails to lift my spirits, and every time I listen to Van Morrison’s Astral Weeks or to Emmylou Harris’ Wrecking Ball I feel myself to be in the presence of something exquisitely rare and fine.

When we say that music moves us, we mean that it opens us up to our own experience, to moments of intense pleasure or pain or a mixture of both, when we feel the possibility of something new in our lives. What is at stake is nothing less than our ability to feel, so often numbed through choice or necessity. It is this ability that music protects, expands and illuminates.