What's the score?

Nearly 12 years after John Cage's death, in August 1992, many of the opinions about the significance, or insignificance, of this maverick genius among American composers remain unshakeable. Steve Reich, for instance, affirms a real love for the melodic or highly rhythmic, sometimes gamelan-influenced percussion and prepared-piano music that Cage wrote before 1951. In that year, Cage began using chance operations, and Reich completely denigrates everything he did during the ensuing four decades.

In the John Cage Uncaged weekend, Reich would be happiest at Sunday lunchtime with Rolf Hind's selection of the 1946-48 Sonatas and Interludes, Cage's magnificent collection of pieces for a piano modified with all manner of bits and pieces between its strings. Or, possibly, with the all-night performance beginning on Saturday evening of Satie's Vexations, with its 840 repetitions of the same weirdly mournful piano sequence.

John Adams admits to having given his soul over to Cage in his youth. But in the programme book for John Cage Uncaged, he writes that "while young composers were tossing coins and juggling numbers to void the ego, the rest of our contemporaries, unencumbered by theory or musical politics, were simply having a great time listening to Miles Davis, the Stones, Aretha Franklin or - horror of horrors - Glenn Gould playing Bach. In the end, it seems that the expressive potential of music - call it the 'ego' if you will - is what makes it meaningful." For Adams today, "Cage's life and work stand as a kind of spiritual house-cleaning."

Even Earle Brown, who when young was a close associate of Cage's (his own, very beautiful, and very un-Cagean, 1973 composition, Centering, will be heard on Sunday afternoon), was critical of his colleague from early on. And ruminating shortly before his own death, 18 months ago, about who were the artistic geniuses of the 20th century, he particularly praised Picasso, Pollock and Rauschenberg, and then added: "They didn't spend 40 years tossing coins and calling the results music." Ouch!

Yet Brown could be very generous about Cage and, as with many other composers, his line was similar to that of Morton Feldman, another of Cage's 1950s associates. "Quite frankly," Feldman once wrote, "I sometimes wonder how my music would have turned out if John had not given me those early permissions to have confidence in my instincts." Three works by Feldman, who died in 1987, will also be heard next weekend.

The story of the revolution Cage wrought at the beginning of the 1950s usually focuses on the matter of chance operations - often involving the tossing of coins to make musical decisions. Later, what is often called "indeterminacy" saw a greater, but often misunderstood and abused, flexibility deriving from notations that are sometimes much more ambiguous in nature.

John Cage Uncaged contains many such examples, especially of the latter, including Song Books (promised in a very theatrical interpretation as part of the concluding concert on Sunday night). A previously unperformed one is Variations I for Stephen Montague, a graphic interpretation by Cage himself, made in 1990, of his classic 1958 work Variations I. This was written in response to frequent requests for a piece from Stephen Montague, the artistic adviser to John Cage Uncaged. It will be sung on Sunday at lunchtime.

The crucial matters, however, are not precisely how Cage used chance or indeterminacy, but why he didn't want to make choices himself, and how we should listen to the results. For by freeing his music from the baggage of his own expressive concerns, Cage was able to make fresh discoveries that literally couldn't have arisen through the agency of human selection. And in listening to Cage's later music, we are, it seems to me, entering a delightfully varied musical landscape in which the best pieces - such as Atlas Eclipticalis, Winter Music and Cartridge Music, all to be heard simultaneously on Saturday evening - are marked by the way in which they draw you into sound itself, and even into perceiving new kinds of relationships between sounds (something Cage himself tended to decry).

Cage's influence may, as Adams suggests, be most lasting on art forms other than music: Cage has an enormous, and continuing, impact on performance art, on multimedia work, on film and even on the more fixed forms of painting and sculpture. He also has ongoing consequences, however, for musicians and music students who, in my experience both here and in the USA, are currently turning enthusiastically to the composer's ideas, reviving the notion of "experimental music" with a fresh approach.

Some of these enthusiasts will doubtless be among the 341 performers (at the last count) in Montague's latest realisation of Cage's Musicircus, which promises to fill the foyers and gallery of the Barbican Centre with even more glorious mayhem than the last one there in 1998. (Preceding this, Stefan Buczacki gives a lecture on the mushroom garden he has provided for the occasion; Cage himself was a well-informed mycologist.)

Yet, 12 years after his death, Cage remains more talked about than performed, especially in Britain: something that Ann McKay, the chief producer of the BBC Symphony Orchestra and the brains behind John Cage Uncaged, is particularly keen to change.

As the bizarre concluding item to a bizarrely un-Cagean programme including Aaron Copland and William Schuman on the opening night, Lawrence Foster will conduct Cage's infamous "silent piece", 4'33" using for perhaps the first time anywhere a large orchestra for the performance. The piece is in three movements and is completely lacking any intended sounds from the performers, making one listen to natural and unintended sounds in a new way. It seems that Foster is among the many who believe in the old adage that Cage's ideas are more interesting than his music; though he has some interesting ideas of his own about performing 4' 33" which it would perhaps be wrong to reveal here.

As for the BBC Symphony Orchestra, heaven only knows what they will make of it, even if professional decorum carries the day. One of McKay's and Montague's biggest challenges in organising this event - which, in common every BBC/Barbican January weekend, is built around the BBCSO - has been that Cage's utopian visions never cut much ice with orchestras and orchestral players.

You can decide about all this for yourself next weekend, even if you can't be at the Barbican. For the BBC Radio 3 broadcast of the "silent piece", the sound engineers have even been cajoled into taking offline the usual emergency systems that normally kick in after 45 seconds of "dead time". In life, as in art, Cage continues to make an impact.

John Cage Uncaged is at the Barbican, London EC2 (0845 120 7596) from Friday to Sunday and on BBC Radio 3 and BBC 4