The release of the South Bank Centre's programme for The Rest Is Noise is cause for celebration: here is a national institution committing a year of events to the idea that the culture of the 20th century cannot be neatly divided into high- and lowbrow, difficult and popular. The festival takes its name and its curatorial principles from a book and blog by a music critic. By happy coincidence, Alex Ross's The Rest Is Noise won the Guardian first book award four years ago this week; his catholic taste was evident that night in a guestlist ranging from classical luminaries to Radiohead's Jonny Greenwood. Its success and influence places Ross in a line of critic proselytisers that stretches back to Ken Tynan and George Bernard Shaw. It's in the nature of a proselytising festival to be controversial, so let us pause, before the dissonance begins, to consider what an achievement this is, in an age when the critic is sometimes written off as a cultural irrelevance.