Meanwhile, I cannot think of a previous time in our culture when significant composers in numbers evolved their identities outside (and in such hostility to) the norms of peers, training and institutions. Even those confirmed radicals Debussy and Stravinsky, busy renouncing much of what their recent past offered, managed to continue the embodiment of cultural identities that we still recognise respectively as “French” and “Russian”. More recently, however, we note a cohort of composers whose well-spring seems located in their very alienation from previous art musics; the biographies of figures like Cowell, Scelsi, Partch, Sorabji and Nancarrow (all of them born within about 20 years) begin with phrases like “although having no formal training” or “rejecting much of the classical mainstream”. I’m not sure we could find that narrative in previous ages, imbued as they were with a sense of craft and social function more than by the otherness of a new music. That “The Shock Of The New”, in Robert Hughes’s phrase, is a modern priority in art will surprise no one, but the uprooting of time-honoured assumptions that it brings was so extensive that it is worth revisiting the profound imprint of this on today’s mindset. To make a start: if this tangled environment, this cat’s cradle of individuated cultural filaments, really is distinctive from its predecessors in this respect, I think one specific trait in the fraying of any mainstream in music will be the disintegration of instrumental medium (or genre) — though this in itself is only a reflection of a wider shift, to “the new individuation” in art.

The creeping loss of instrumental genre in art music to me stands as a fascinating and elusive spectre amid our cultural space, strongly indicative but strangely undiscussed — an eloquent elephant in our front room. Of course, instrumental genres continue to survive among modern composers — notably the symphony, whose adherents are impressively diverse and individual: Vaughan Williams, Shostakovich, Gerhard, Harris, Henze, Tippett, Maxwell Davies, Nørgård, Rautavaara, Kalevi Aho, Daniel Börtz, Christopher Rouse, Lutosławski — the exceptions are impressive. Nor is canonic string quartet production gone, with  Bartók and Shostakovich being followed by multiple works by Tippett, Britten, Nørgård, Rihm, Harvey, Ferneyhough and Carter, to name only a few. Yet these continuing “collected” expressions are exceptions, even striking ones; it is not unusual for a premiere of a new symphony to be accompanied by a panel on “the survival of the symphony”, with a debate over what it continues to offer the composer. The composer of a fifth string quartet will be asked “why do you continue to return to this medium?”, as if perpetrating another quartet is like a reckless entanglement in a further, ill-advised marriage (which of course it can be). But questions about “the survival” of the symphony were probably not asked regularly of Brahms, as he struggled to be worthy of Beethoven’s legacy. His doubts, in turn, were about working in the shadow of Beethoven, rather than about the wider validity of continuing with the symphony per se.

So let me invoke a modern neurosis — which I’m going to term genre-panic — around instrumental media. In a century blessed by the hyper-facility of neo-classical figures like Milhaud and Hindemith, compositional genre has not aged well — sounding warning bells, for our individuated age, about mass production and “sewing-machine music”. In the 2013 BBC Reith Lectures Grayson Perry quoted the radical artist Marcel Duchamp as saying, “Abundant production can only result in mediocrity” — a clear expression of the modernist division between artefact and product, between individuation and mass-participation. Such a division would have baffled the productive Haydn, the prodigious Mozart or the phenomenal Schubert, many of whose works were instantly digestible to their public but still hardly separable in style from their most experimental masterpieces.