Inside Llewyn Davis, the latest from the Coen Brothers, is playing in cinemas at a time when folk legend Pete Seeger has just died. This import from the real world contextually foreshadows a movie already dense with ideas and subtle artistry. It’s a reminder of what the folk revival meant in the ‘60s. Yes there were beards, polo necks and the gentle wanking of guitars but underpinning it all was disaffection and the sense that music could act as a balm, bringing together those who for one reason or another felt disenfranchised by cultural upheaval and political change.

The wonderful thing about Davis is that it manages to both evoke and tap into all of this without being didactic or revisionist from a modern perspective. In what is a nigh on plotless affair, Oscar Issac’s solo singer, a partner down since a suicide on the George Washington Bridge, goes on a personal odyssey, in hoc to a cat portentously, metatextually named Ulysses, sifting through the detritus of an unfulfilled, fragmented life; frustrated artistic ambitions, a lost child, a woman  – Carey Mulligan, who doesn’t want his next child, an estranged family and suppressed rage at a dead partner. In short it’s the type of film that’s ostensibly about very little but in reality touches everything; it’s an excavation of a life.

Davis is the perhaps the most jaded, cynical and aggressive folk singer-songwriter you’ve ever encountered, but therein you feel is the comment on a burgeoning scene. Davis is the kind of guy he may be tempted to sing about; hard up, powerless, screwed by the government (red tape prevents his escape into naval service) – a prophet no one listens to and no one’s interested in, in search of a kindred spirit. It might be tragic if it wasn’t so good humoured and this is where the Coen’s offbeat sensibility and predilection for leftfield characters is a perfect fit for the world they’ve chosen to explore.

Photographed to be as placid and earthy as a stereotypical folk record, Inside Llewyn Davis is invested with the all the characteristics of a great song. It’s heartfelt, moving, changes key a few times before ending as it began, and all the while retaining a degree of ambiguity that will bring people back to it many times over. In the past Joel and Ethan Coen have sometimes erred as they’ve over indulged on their kooky schick but here all is balanced, all is rounded.