This enigmatic piece of advice was given by the Hungarian professor György Sebök, whose masterclasses I attended in Switzerland, Canada and Holland in the 1980s. Like many of his aphorisms it was casually delivered with a wry smile, a curl of cigarette smoke and a look that said, ‘If you think about this for as long as I have, it may make sense to you.’

I used it as the title of a talk I gave not long ago at King's College, London, where my academic audience was vexed by Sebök's words. For them, the division into ‘container’ and ‘contents’ cut across the fashionable theory of semiotics, the study of sign and communication. Music is an example of a ‘sign’. The ‘sign’ can be divided into the ‘signifier’ (in the case of music, the sound) and the ‘signified’ (the sense). Some think that music, the least representational of the arts, has no ‘sense’ of its own, and that it is only we who feel an irresistible need to give it meaning. Certain composers have appeared to lend weight to this argument by refusing to say what the meaning of their music is, or even by claiming that there is none.