Townes van Zandt, the man Steve Earle thought to be the greatest songwriter of his generation, was once asked why he only wrote sad songs. “Well,” he answered, “many of the songs, they’re not sad, they’re hopeless.”

This remark is somewhat misleading with regard to van Zandt’s work: listening to one of his many available live shows from start to finish is a varied experience, for he can be hilariously funny as well as hopelessly sad, and he finds room for many worlds in between. But in a sense “hopeless” is right: many of van Zandt’s songs mourn or celebrate our inability to hold on to things – love, each moment as it passes, life itself. As he puts it in The Highway Kind, one of his most memorable songs, “My days they are the highway kind / They only come to leave. / But the leaving I don’t mind / It’s the coming that I crave.”

If you can’t get what you want (or, just as often, don’t know what you want), there are a few strategies open to you: you can move on or stay put, negotiating a relationship between you and the world, or you can surrender to nostalgia and/or madness.

Townes himself wrote his share of songs about moving on, often in a voice that manages to be wistful and heroic at the same time. “To live’s to fly / All low and high / So shake the dust off of your wings / And the sleep out of your eyes”, one of them counsels, and the way his voice stops just short of the appropriate note at times hints that just getting off the ground is not going to be easy.

Another heroic lyric about moving on and somehow staying behind at the same time was written by Barbara Fairhead about two years ago and entrusted to me to set to music. It was called Dark Mercy, and it describes two people, probably lovers, standing together at the edge of an expanse of water as the sun sets over it. The first-person speaker wants to hold on to this moment, but knows that night will claim it in the end. This realization is somehow both chilling and merciful – hence the title.

The mad song about holding on to the impossible dream is exemplified for me by a Richard Thompson track that never made it onto an official studio release, From Galway to Graceland. It is a song about a woman who leaves the life she knows without a second thought in order to be with her beloved: “To be with her sweetheart / Ah, she left everything / From Galway to Graceland to be with the king.” I sing it compulsively, just to make sure it is still as wonderful as I remember it. Needless to say, it always is.

From Galway to Graceland is poignantly double-edged: the sense of release at the beginning of the song is palpable in Thompson’s lilting voice as well as in the lyrics: “And silver wings carried her over the sea / From the west coast of Ireland to West Tennessee.” Gradually it emerges that the object of her affections, her king, is in fact the long-dead Elvis Presley.

The irony is a cruel one, but that sense of release stays with you, too. In the end it is the lass from Galway who has the last word, and her stubborn refusal to accept things as they are feels heroic as well as tragic: “I’ve come from Galway to Graceland to be with the king.” That mad, hopeless journey is redeemed because it is more imaginative than the people who judge or ignore it.

What these songs share is a kind of generosity. In chronicling these fraught negotiations with time and place, they give us strength for the long road ahead – that is the dark mercy they show us.