Classical: On Air

SETTLING THE Score last Sunday afternoon on Radio 3 surveyed the bewildering world of 20th-century harmony. Harmony, Stephen Sondheim said, is what gives a composer particular character - and went on to challenge that assertion by confessing he took some of his chords from Ravel. The result didn't remind me of Ravel.

There was a substantial sequence of extracts from pieces written by Stravinsky at different periods, putting his character to the test. But the most characteristic thing about Stravinsky is his method of continuity - or discontinuity - and his character is not reducible to any of the single elements of rhythm, harmony or melody.

Then there was a telling editorial juxtaposition of music from Stockhausen's Stimmung and Debussy's Fetes to show, without a word being said, that identical pitches don't necessarily make for similar music. What's in a chord?

Anyway, "What do we mean by harmony?" enquired Harrison Birtwistle, sounding slightly put upon. This was a real question, for Birtwistle has almost as little harmonic sense as any 20th-century composer, and there was a touching eloquence in his absence from the next 20 minutes or more, before he popped up again, explaining, "What I control is intervals!" - as if some unseen or unheard inspector from the Arts Council had accused him of laxity.

Schoenberg's 12-note method bypassed an independent grammar of harmony altogether, even though Schoenberg himself was a connoisseur of harmony. But then James Wood was confident that Schoenberg's method would not turn out to have been one of the most significant innovations of the century, as we once thought.

Alexander Goehr - franker than you expect a Cambridge professor to be - confessed he had been to see Sir Michael Tippett (before he died) and told him he was worried about his (Goehr's) lack of harmonic sense. He would write something but not be able to remember the harmonies the following day. "Funny you should say that," returned Tippett. "I've been trying to write coherent and expressive music without harmony all my life."

But then the harmonic series, or overtones present in a note, do suggest that some sort of tonality is natural, even if it isn't the system of major and minor scales or the harmonic vocabulary built upon them that European theorists codified a few hundred years ago. French avant-garde composers such as Gerard Grisey and Tristan Murail have explored the higher regions of the harmonic series, beyond the bounds of tempered tuning systems, and John Tavener mumbled benevolently about the "harmony of the spheres".

The rediscovery of clear and simple harmonies in composers such as Arvo Part, Steve Reich and Tavener came with a sigh of relief, said James Wood. Or a groan of boredom in the case of Pierre Boulez, who said he didn't like being able to predict what he would hear, hinting at a subject for a whole new programme.

It was all very well for Debussy to shock a conservative professor by saying, "There is no theory, you merely have to listen", for the boat he was rocking hadn't yet sunk. Nearly a hundred years later, Gyorgy Ligeti admitted that in the Sixties he had thought clusters the new language, only to realise they were a mirage, although those weren't exactly his words. "I was lost, and I am still lost."